Preface

The book focuses on different areas of recent developments in communication research. Topics that are covered in the book comprise secure communication, error control, different generations of communication networks, software-defined networks, communication protocols, circuit design issues for communication, and multimedia data communication. All these research methodologies indicate how computing and communication technology complement each other. Communication technology has greatly enhanced computing power from stand-alone computers to networked systems to distributed systems. Advanced computing techniques have supplemented this development, thus ensuring secure, error-free, and uninterrupted transmission in different communication environments. The book presents different recent research problems in the area of communication. The content of the book will be beneficial for future generations of communication research.

I would like to express my sincere thanks to my postdoctoral fellow Dr. Behrouz Zolfaghari for carrying out several reviews that helped me in editing the book. Last but not least I would like to convey my sincere thanks to Mrs. Dolores Kuzelj, the Author Service Manager, who had provided constant support in the entire editing process of the book.

**II**

**Chapter 8 121**

Electronic Circuit Design **147**

**Chapter 9 149**

**Chapter 10 169**

Multimedia Communication **183**

**Chapter 11 185**

Network Routing Protocols **203**

**Chapter 12 205**

**Chapter 13 225**

Design Principles of 5G NR RoF-Based Fiber-Wireless Access Network *by Mikhail E. Belkin, Tatiana N. Bakhvalova and Alexander S. Sigov*

Design and Analysis of Analog to Digital Converter System Clock

Understanding of On-Chip Power Supply Noise: Suppression

*by Pritam Bhattacharjee, Prerna Rana and Alak Majumder*

*by Kunwar Pal, Mahesh Chandra Govil, Mushtaq Ahmed* 

Secure and Energy-Efficient Communication in IoT/CPS *by Saad Alharthi, Princy Johnson and Martin Randles*

A Mobile Ad Hoc Network Routing Protocols: A Comparative Study

Source Using Direct Digital Synthesizer

Methodologies and Challenges

*by Alagan Ramasamy Rajeswari*

*by Desmond Tung and Rosmiwati Mohd-Mokhtar*

A Survey on Adaptive Multimedia Streaming

**Section 4**

**Section 5**

**Section 6**

*and Tanvi Chawla*

**Pinaki Mitra** Professor, Department of Computer Science and Engineering, Guwahati, India

**1**

Section 1

Introductory Chapter

Section 1

## Introductory Chapter

**3**

**Figure 1.**

**Chapter 1**

Networks

*Pinaki Mitra*

**1. Introduction**

communication technology.

and packet switching.

to perform modulation and demodulation.

*Illustration of data communication in computer networks.*

Introductory Chapter: Recent

With the emergence of distributed computing platforms and computer networks in the last few decades, there is almost no stand-alone computer anymore. In the last few decades, stand-alone computers in a distributed system communicate in order to share computing power. Communication in computer networks was initially aiming at resource sharing, but nowadays it serves to a variety of functions including computing power sharing. There has been plenty of research works in the area of communications focusing on the development of new networking protocols, transmission media, and different generations of

**Figure 1** shows the communication between two hosts in its simplest form. Hosts in computer networks are no longer confined to computers; they can be cell phones, tablets, smart sensors, and so on. In **Figure 1**, the function of the modem is

During the course of time, different types of networks evolved. The initially existing telephone network was used for the purpose of computer communication. This was circuit-switched. There was no buffering in intermediate nodes. Subsequently message-switched network evolved that used the concept of storing in buffer and forwarding. Then packet-switched network came, where messages are fragmented into small-sized packets that can be stored in primary memory, unlike earlier messages that needed secondary storage. Subsequently, we had frame relay, ATM, and virtual circuit packet switching that is a combination of circuit switching

Moreover, a variety of multiplexing techniques are used in data communications. Some commonly used multiplexing techniques are frequency division multiplexing or FDM, time division multiplexing or TDM, and statistical time-division multiplexing. Frequency-division multiplexing used modulation at sender end and demodulation at the receiving end. But it was not very popular like TDM. But in the recent generation of communication, networks are using orthogonal

Trends in Communication

#### **Chapter 1**

## Introductory Chapter: Recent Trends in Communication Networks

*Pinaki Mitra*

#### **1. Introduction**

With the emergence of distributed computing platforms and computer networks in the last few decades, there is almost no stand-alone computer anymore. In the last few decades, stand-alone computers in a distributed system communicate in order to share computing power. Communication in computer networks was initially aiming at resource sharing, but nowadays it serves to a variety of functions including computing power sharing. There has been plenty of research works in the area of communications focusing on the development of new networking protocols, transmission media, and different generations of communication technology.

**Figure 1** shows the communication between two hosts in its simplest form. Hosts in computer networks are no longer confined to computers; they can be cell phones, tablets, smart sensors, and so on. In **Figure 1**, the function of the modem is to perform modulation and demodulation.

During the course of time, different types of networks evolved. The initially existing telephone network was used for the purpose of computer communication. This was circuit-switched. There was no buffering in intermediate nodes. Subsequently message-switched network evolved that used the concept of storing in buffer and forwarding. Then packet-switched network came, where messages are fragmented into small-sized packets that can be stored in primary memory, unlike earlier messages that needed secondary storage. Subsequently, we had frame relay, ATM, and virtual circuit packet switching that is a combination of circuit switching and packet switching.

Moreover, a variety of multiplexing techniques are used in data communications. Some commonly used multiplexing techniques are frequency division multiplexing or FDM, time division multiplexing or TDM, and statistical time-division multiplexing. Frequency-division multiplexing used modulation at sender end and demodulation at the receiving end. But it was not very popular like TDM. But in the recent generation of communication, networks are using orthogonal

**Figure 1.** *Illustration of data communication in computer networks.*

frequency-division multiplexing (OFDM). Also in communication technology, we had the development of GSM, spread spectrum, and CDMA.

Another aspect of data communication which has witnessed a variety of developments is the technology of the transmission media. It can be either wired or wireless. For wired transmission media, we had twisted pair, coaxial, and fiber-optic cables. Research had been carried out to reduce signal distortion due to attenuation, delay, and interference of different types of noise. Equalization techniques are used to avoid different distortions. In wireless communication, we use microwave communication or satellite communication using geostationary satellites.

The next important issue related to the communication network is the development of network protocols. Initially, we had seven-layered ISO/OSI protocols. After that five-layered TCP/IP protocol evolved. The purpose of these protocols was to ensure error control, flow control, and routing and congestion control. In these protocols, there is a virtual communication between corresponding layers in two different nodes. This takes place through the appending of packet headers, while the information moves down the layer at the source node and removal/stripping of the packet header by the corresponding layer, while the information flows up in the destination node. With recent developments of the Internet of things (IOT), a modified version of TCP/IP protocol evolved named 6LoWPAN. These protocols are not only implemented in the communicating nodes/computers of the communication network but also at routers and switches.

With the increased use of communication networks in day to day life, they became susceptible to attacks from malicious users. There are usually two different types of attacks, namely, passive attacks and active attacks. In passive attacks, the transmitted information is leaked to the eavesdropper but the transmitted message remains unaltered. This can be avoided by using sophisticated encryption and decryption methodologies. In contrast, active attacks involve modification of message content, masquerade, non-repudiation, and denial of service. The modification of message content can be handled using different error detection and error correction methods. There had been several works related to different types of coding in the field of communication research. Nonrepudiation can be handled by the cryptographic technique of digital signatures or message authentication code (MAC). Denial of service involves flooding of networks with garbage packets from malicious users. Several machine learning techniques for outlier or anomaly detection are used to detect such attacks.

Performance evaluation of different communication techniques can be carried out using the following four quality of service or QoS parameters. They are throughput, packet loss, delay, and jitter/delay variation. We have to suitably adjust the trade-off between these parameters to optimize the quality of service.

Nowadays, we use several mini handheld devices that use the features of the mobile communication network. These devices usually have very limited storage, computing power, and energy. For this purpose, several types of research had been carried out to reduce the computation and communication overheads without compromising accuracy, security, etc. Another important difference in the area of the mobile communication networks is unlike earlier networks whose topology is always fixed; here we have to handle the problem of variable topology. The interconnecting link between two nodes of the network may or may not exist during the course of time. Usually, each node in the network has a limited transmission range. Connections are established between two mobile nodes that are within the range. These links will cease to exist when these two nodes go out of range of each other. These networks are also called MANET or mobile ad hoc networks. There are several issues that are different for routing of packets in MANET as compared to fixed interconnection networks. Several types of research had been carried out

**5**

*Introductory Chapter: Recent Trends in Communication Networks*

for the design of routing protocols in MANET that are also susceptible to various attacks. A recent development in the area of MANET is the vehicular ad hoc networks (VANET). Since a huge amount of data and computation is involved here, several techniques from big data analytics are employed to improve efficiency.

existing disciplines of computing like operating systems, database, and communication. Multimedia data involves a mixture of image, text, audio, video, and graphics data. These are usually referred to as multimedia content. In the field of operating systems, the advent of multimedia had led to the development of realtime operating systems. Different scheduling algorithms like the earliest deadline first or EDF and rate monotonic algorithm or RMA are adopted for these applications. In the field of the database due to multimedia, we had seen the development of object-relational DBMS where we can efficiently perform content-based retrieval. In the area of communication, the advent of multimedia had led to video on demand. The communication protocol that is used for multimedia communication is RTP that usually runs over UDP that is a simplified version of TCP. We had seen the development of different types of a content distribution network or CDN for this purpose. Since in communication video data involve large uplink/ downlink bandwidth, research had been carried out to transmit these data as a mix of different definitions. High-definition video is meant for nodes having large bandwidth for downlink purposes. Medium-definition video is meant for nodes having moderate bandwidth for downlink purposes. Low-definition video is meant for nodes having low bandwidth for downlink purposes. In content distribution network in addition to four quality of service, an additional parameter is introduced that measures the user's feeling or experience of the displayed video satisfying the bandwidth constraint. This is also known as the Quality of Experience (QoE). Usually, this parameter is quantified using peak signal-to-noise ratio or PSNR value

Recent developments in different branches of communications technologies have led to hybrid technologies such as mobile satellite communication (SATCOMM) which are finding their applications in several environments such as

one can refer to security and specially copyright protection issues.

In recent years, there has been a fruitful interaction between computer network technology and other emerging technologies. Computer networks are now used to provide cloud services. They are interacting with fog computing technology to build content delivery networks. The latter networks provide a lot of services including social networking, digital cinema, etc. But with the development of the ecosystem of these networks, a variety of challenges and requirements are raised among which

For recent developments related to communication and networks readers are suggested to refer to [1–4]. For recent developments in the area of network security,

In the field of computers with the advent of the Internet, the topic of computer communication gained significant importance. Different modulation and demodulation techniques evolved for improved long-distance communication. Switching techniques handled efficient data transmission. Different generations of communication networks like 3G, 4G, 5G, and so on evolved in the course of time. Different communication network protocols evolved. These networks got susceptible to various types of attacks. The theory of cryptography and coding theory evolved to handle many

Recently the development of multimedia had enhanced developments of various

*DOI: http://dx.doi.org/10.5772/intechopen.90856*

of the displayed video stream.

unmanned aerial vehicle (UAV) systems.

readers are suggested to refer to [5].

**2. Conclusion**

#### *Introductory Chapter: Recent Trends in Communication Networks DOI: http://dx.doi.org/10.5772/intechopen.90856*

*Recent Trends in Communication Networks*

frequency-division multiplexing (OFDM). Also in communication technology, we

Another aspect of data communication which has witnessed a variety of developments is the technology of the transmission media. It can be either wired or wireless. For wired transmission media, we had twisted pair, coaxial, and fiber-optic cables. Research had been carried out to reduce signal distortion due to attenuation, delay, and interference of different types of noise. Equalization techniques are used to avoid different distortions. In wireless communication, we use microwave com-

The next important issue related to the communication network is the development of network protocols. Initially, we had seven-layered ISO/OSI protocols. After that five-layered TCP/IP protocol evolved. The purpose of these protocols was to ensure error control, flow control, and routing and congestion control. In these protocols, there is a virtual communication between corresponding layers in two different nodes. This takes place through the appending of packet headers, while the information moves down the layer at the source node and removal/stripping of the packet header by the corresponding layer, while the information flows up in the destination node. With recent developments of the Internet of things (IOT), a modified version of TCP/IP protocol evolved named 6LoWPAN. These protocols are not only implemented in the communicating nodes/computers of the communi-

With the increased use of communication networks in day to day life, they

became susceptible to attacks from malicious users. There are usually two different types of attacks, namely, passive attacks and active attacks. In passive attacks, the transmitted information is leaked to the eavesdropper but the transmitted message remains unaltered. This can be avoided by using sophisticated encryption and decryption methodologies. In contrast, active attacks involve modification of message content, masquerade, non-repudiation, and denial of service. The modification of message content can be handled using different error detection and error correction methods. There had been several works related to different types of coding in the field of communication research. Nonrepudiation can be handled by the cryptographic technique of digital signatures or message authentication code (MAC). Denial of service involves flooding of networks with garbage packets from malicious users. Several machine learning techniques for outlier or anomaly detection are used to detect such attacks. Performance evaluation of different communication techniques can be carried out using the following four quality of service or QoS parameters. They are throughput, packet loss, delay, and jitter/delay variation. We have to suitably adjust

the trade-off between these parameters to optimize the quality of service.

Nowadays, we use several mini handheld devices that use the features of the mobile communication network. These devices usually have very limited storage, computing power, and energy. For this purpose, several types of research had been carried out to reduce the computation and communication overheads without compromising accuracy, security, etc. Another important difference in the area of the mobile communication networks is unlike earlier networks whose topology is always fixed; here we have to handle the problem of variable topology. The interconnecting link between two nodes of the network may or may not exist during the course of time. Usually, each node in the network has a limited transmission range. Connections are established between two mobile nodes that are within the range. These links will cease to exist when these two nodes go out of range of each other. These networks are also called MANET or mobile ad hoc networks. There are several issues that are different for routing of packets in MANET as compared to fixed interconnection networks. Several types of research had been carried out

had the development of GSM, spread spectrum, and CDMA.

cation network but also at routers and switches.

munication or satellite communication using geostationary satellites.

**4**

for the design of routing protocols in MANET that are also susceptible to various attacks. A recent development in the area of MANET is the vehicular ad hoc networks (VANET). Since a huge amount of data and computation is involved here, several techniques from big data analytics are employed to improve efficiency.

Recently the development of multimedia had enhanced developments of various existing disciplines of computing like operating systems, database, and communication. Multimedia data involves a mixture of image, text, audio, video, and graphics data. These are usually referred to as multimedia content. In the field of operating systems, the advent of multimedia had led to the development of realtime operating systems. Different scheduling algorithms like the earliest deadline first or EDF and rate monotonic algorithm or RMA are adopted for these applications. In the field of the database due to multimedia, we had seen the development of object-relational DBMS where we can efficiently perform content-based retrieval. In the area of communication, the advent of multimedia had led to video on demand. The communication protocol that is used for multimedia communication is RTP that usually runs over UDP that is a simplified version of TCP. We had seen the development of different types of a content distribution network or CDN for this purpose. Since in communication video data involve large uplink/ downlink bandwidth, research had been carried out to transmit these data as a mix of different definitions. High-definition video is meant for nodes having large bandwidth for downlink purposes. Medium-definition video is meant for nodes having moderate bandwidth for downlink purposes. Low-definition video is meant for nodes having low bandwidth for downlink purposes. In content distribution network in addition to four quality of service, an additional parameter is introduced that measures the user's feeling or experience of the displayed video satisfying the bandwidth constraint. This is also known as the Quality of Experience (QoE). Usually, this parameter is quantified using peak signal-to-noise ratio or PSNR value of the displayed video stream.

Recent developments in different branches of communications technologies have led to hybrid technologies such as mobile satellite communication (SATCOMM) which are finding their applications in several environments such as unmanned aerial vehicle (UAV) systems.

In recent years, there has been a fruitful interaction between computer network technology and other emerging technologies. Computer networks are now used to provide cloud services. They are interacting with fog computing technology to build content delivery networks. The latter networks provide a lot of services including social networking, digital cinema, etc. But with the development of the ecosystem of these networks, a variety of challenges and requirements are raised among which one can refer to security and specially copyright protection issues.

For recent developments related to communication and networks readers are suggested to refer to [1–4]. For recent developments in the area of network security, readers are suggested to refer to [5].

#### **2. Conclusion**

In the field of computers with the advent of the Internet, the topic of computer communication gained significant importance. Different modulation and demodulation techniques evolved for improved long-distance communication. Switching techniques handled efficient data transmission. Different generations of communication networks like 3G, 4G, 5G, and so on evolved in the course of time. Different communication network protocols evolved. These networks got susceptible to various types of attacks. The theory of cryptography and coding theory evolved to handle many

such problems. More recently with the advancement of mobile technologies and IoT, these algorithms had to take into consideration limited resources like battery power, storage, and processor capabilities. This had led to the development of new communication technologies for resource-constrained devices. Also in MANET due to time-varying interconnection, there is a necessity to maintain proper integrity and consistency in the distributed data. Due to large volume of data efficient computational techniques from big data analytics are adopted. Also in the recent development of multimedia communication, different adaptive streaming of multimedia content over different types of networks had evolved that would optimize different quality of service and quality of experience parameters. The book addresses these issues that arise in present-day research in the field of communication and networking and also presents several possible directions for future research.

#### **Author details**

Pinaki Mitra Department of Computer Science and Engineering, IIT Guwahati, Guwahati, India

\*Address all correspondence to: pinaki@iitg.ac.in

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**7**

*Introductory Chapter: Recent Trends in Communication Networks*

*DOI: http://dx.doi.org/10.5772/intechopen.90856*

[1] Stallings W. Data and Computer Communications. 8th ed. Pearson;

[2] Gupta P. Data Communications and Network. India: Prentice Hall; 2014.

[3] Pal A. Data Communications and Computer Networks. India: Prentice Hall; 2014. ISBN: 9788120348455

[4] Bertsekas D, Gallager R. Data Networks. 2nd ed. India: Prentice Hall;

[5] Stallings W. Cryptography and Network Security: Principles and Practice. 4th ed. India: Prentice Hall; 2005. ISBN: 978-0-13-111502-6

1992. ISBN: 0-13-200916-1

2006. ISBN: 0-13-243310-9

ISBN: 13: 978-8120348646

**References**

*Introductory Chapter: Recent Trends in Communication Networks DOI: http://dx.doi.org/10.5772/intechopen.90856*

#### **References**

*Recent Trends in Communication Networks*

such problems. More recently with the advancement of mobile technologies and IoT, these algorithms had to take into consideration limited resources like battery power, storage, and processor capabilities. This had led to the development of new communication technologies for resource-constrained devices. Also in MANET due to time-varying interconnection, there is a necessity to maintain proper integrity and consistency in the distributed data. Due to large volume of data efficient computational techniques from big data analytics are adopted. Also in the recent development of multimedia communication, different adaptive streaming of multimedia content over different types of networks had evolved that would optimize different quality of service and quality of experience parameters. The book addresses these issues that arise in present-day research in the field of communication and network-

ing and also presents several possible directions for future research.

**6**

**Author details**

Department of Computer Science and Engineering, IIT Guwahati, Guwahati, India

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: pinaki@iitg.ac.in

provided the original work is properly cited.

Pinaki Mitra

[1] Stallings W. Data and Computer Communications. 8th ed. Pearson; 2006. ISBN: 0-13-243310-9

[2] Gupta P. Data Communications and Network. India: Prentice Hall; 2014. ISBN: 13: 978-8120348646

[3] Pal A. Data Communications and Computer Networks. India: Prentice Hall; 2014. ISBN: 9788120348455

[4] Bertsekas D, Gallager R. Data Networks. 2nd ed. India: Prentice Hall; 1992. ISBN: 0-13-200916-1

[5] Stallings W. Cryptography and Network Security: Principles and Practice. 4th ed. India: Prentice Hall; 2005. ISBN: 978-0-13-111502-6

**9**

Section 2

Security Issues in

Communication

Technology

Section 2

Security Issues in Communication Technology

**11**

**Chapter 2**

**Abstract**

distribution

**1. Introduction**

A Survey on Piracy Protection

Techniques in Digital Cinema

Watermarking is used in several areas such as CDNs (Content Delivery Networks), as part of the rights management system for counterfeit prevention. Watermarking schemes need some additional features in order to be used in digital cinema. In fact, extra watermarks are added to movies by cinema projectors in projection time, which help identify the cinema hall in which the illegal copy has been recorded. But distortions caused by hand vibrations and the point of view angle make it difficult to recover the watermark. This makes it necessary to be distortionresistant for the watermarking schemes used in digital cinema. On the other hand, theatre owners would like to locate the camcorder that has recorded the pirate copy. This requires watermarking schemes to be able to estimate the distance and angle using the distributed pirate copy. In this chapter, we present a review on watermarking techniques specifically designed to attack the aforementioned problems.

**Keywords:** watermarking, piracy, digital cinema, copyright, survey, digital

internet made security more and more challenging [15].

Digital distribution has been considered by researchers since four decades ago [1–3]. With the growth of available bandwidth in the telecommunications infrastructures, it gradually appeared as one of the main purposes of communication during two decades. This encouraged a lot of research on different aspects of digital distribution over internet [4–6]. Digital distribution brings about several challenges among which one can refer to performance, but in this chapter, we are more interested in security. Security of digital distribution has been investigated from different aspects [7–9]. One of the most challenging aspects in digital distribution security is digital rights management, which has been the topic for several research works [10, 11]. With the emergence of internet, online digital distribution found its applications in a variety of environments [12–14]. Meanwhile, the public access to

Content delivery is a branch of digital distribution, which is growing very fast in different aspects [16, 17]. The more content delivery systems grow, the more complex security their security management becomes [18]. Among advances in content delivery, one may mention CDNs [19–21]. These networks serve to high-performance delivery of digital contents as well as streaming of audio and video in collaboration with other technologies such as cloud computing [22, 23].

Watermarking Schemes

*Behrouz Zolfaghari and Pinaki Mitra*

#### **Chapter 2**

## A Survey on Piracy Protection Techniques in Digital Cinema Watermarking Schemes

*Behrouz Zolfaghari and Pinaki Mitra*

#### **Abstract**

Watermarking is used in several areas such as CDNs (Content Delivery Networks), as part of the rights management system for counterfeit prevention. Watermarking schemes need some additional features in order to be used in digital cinema. In fact, extra watermarks are added to movies by cinema projectors in projection time, which help identify the cinema hall in which the illegal copy has been recorded. But distortions caused by hand vibrations and the point of view angle make it difficult to recover the watermark. This makes it necessary to be distortionresistant for the watermarking schemes used in digital cinema. On the other hand, theatre owners would like to locate the camcorder that has recorded the pirate copy. This requires watermarking schemes to be able to estimate the distance and angle using the distributed pirate copy. In this chapter, we present a review on watermarking techniques specifically designed to attack the aforementioned problems.

**Keywords:** watermarking, piracy, digital cinema, copyright, survey, digital distribution

#### **1. Introduction**

Digital distribution has been considered by researchers since four decades ago [1–3]. With the growth of available bandwidth in the telecommunications infrastructures, it gradually appeared as one of the main purposes of communication during two decades. This encouraged a lot of research on different aspects of digital distribution over internet [4–6]. Digital distribution brings about several challenges among which one can refer to performance, but in this chapter, we are more interested in security. Security of digital distribution has been investigated from different aspects [7–9]. One of the most challenging aspects in digital distribution security is digital rights management, which has been the topic for several research works [10, 11]. With the emergence of internet, online digital distribution found its applications in a variety of environments [12–14]. Meanwhile, the public access to internet made security more and more challenging [15].

Content delivery is a branch of digital distribution, which is growing very fast in different aspects [16, 17]. The more content delivery systems grow, the more complex security their security management becomes [18]. Among advances in content delivery, one may mention CDNs [19–21]. These networks serve to high-performance delivery of digital contents as well as streaming of audio and video in collaboration with other technologies such as cloud computing [22, 23].

Different aspects of security in CDNs such as privacy [24], digital property management [25], intrusion detection [26], trust [27], and eavesdropping protection [28] have been studied by researchers.

Digital cinema is a service that can be provided using CDNs. It is an online video streaming and projection service gaining a research focus in recent years [29–31]. Security is a serious challenge in digital cinema [32–34] like other services provided over CDNs. One of the most important aspects of digital cinema security is digital rights management [35, 36], which is about preserving the publication rights for the generator of contents. Counterfeit protection is one of the most challenging problems in the area of digital cinema rights management.

Digital property management and especially counterfeit protection mostly depend on watermarking in a variety of environments [37–39]. Digital watermarking has been finding its applications in digital cinema in recent years [40, 41]. But, there is a delicate challenge faced by watermarking systems used in digital cinema. In the absence of proper protective measures, counterfeit copies of movies can be recorded by handheld cameras in the cinema hall. Movie theater holders are obliged to take preventive measures in this regard. This creates two problems, which need to be taken into consideration while designing watermarking schemes for digital cinema. These problems are explained in the following.

The first problem is faced by movie providers. When a pirate copy is distributed, providers would like to identify the theatre where the copy has been recorded. Then they can sue the identified theatres as they have not fulfilled their legal obligations. One way to approach this problem is to add watermarks to the movie by the projector in projection time. This watermark carries some identification information about the cinema hall as well as the projection time. This makes it possible to identify the hall in which a counterfeit copy has been recorded. But, the distortions made by hand vibrations and point of view angle, makes it difficult to recover the watermark from the movie. Thus, watermarking schemes designed for digital cinema should be specifically resistant against these distortions.

The second problem is to locate the seat on which the camcorder has been recording. This problem is to be solved by cinema holders as they are legally responsible for illegally recorded copies. Solving this problem requires digital cinema watermarking schemes to be able to calculate distance and angle.

There are some surveys on techniques used to solve the two problems mentioned above. But, they are outdated for such a fast-growing area [42, 43]. This motivates our work in this chapter, which is a comparative review on watermarking schemes used in digital cinema and the methods used by these schemes in order to achieve the mentioned goals.

The rest of this chapter is organized as follows. Section 2 presents an introduction to digital cinema. Section 3 discusses watermarking and related concepts. Section 4 presents a survey on watermarking in digital cinema. Section 5 concludes the chapter and suggests further research.

#### **2. Digital cinema**

Digital cinema refers to the set of processes, tools, and components which aim at the preparation, transmission, and projection of digital movies in cinema. This system is taking the place of traditional cinema which depends on reels of film being projected by film projectors.

In digital cinema, 2K (2048 × 1080 or 2.2 megapixels) or 4K (4096 × 2160 or 8.8 megapixels) resolutions are commonly used.

**13**

standard.

**Figure 1.**

*A typical digital cinema system.*

**3. Digital watermarking**

*A Survey on Piracy Protection Techniques in Digital Cinema Watermarking Schemes*

Among the advantages of digital cinema, we can point out reduction in time to

A digital cinema system consists of three main processes. In the first process, the film is converted to a digital print called DCP (Digital Cinema Package). The DCP is then delivered to the theatres and ingested (stored) by the related servers. This can be done through physical transportation of hard disks or through a digital distribution system. A content delivery network can serve to this purpose [44]. The DCP is often encrypted, and the keys required to decrypt the file are ingested in the screening tools to prevent theater owners from illegal screen extensions. In the third process, the movie is played back using a digital video projector. The aforemen-

The first system specification for digital cinema was published in 2005 by a consortium of six major studios. This specification is referred to as DCI (Digital Cinema Initiatives) and uses JPG 2000 video encoding with XML playback

Watermarking is a copyright ownership identification method used for noisetolerant media such as video, image, and audio. In this technique, an intentional noise is added to the signal in the form of covertly embedded information. In most cases, the hidden information is normally not perceptible. Rather it requires some revealing process to be extracted from the carrying content file. However, in some cases, it can be perceptible. For example, it can be visibly added to a film or image in

The hidden information should be robust (resistant) against simple modifications normally used to the media type. For example, a marker hidden in an image

Steganographic techniques such as watermarking and steganography are evaluated using measures like robustness, imperceptibility, and capacity. In watermarking, the main objective is robustness. It should not be confused with steganography

**Figure 2** shows how the character "a" can be watermarked in a video using a

order to encourage the user to buy the original version without the mark.

should not be removed when the image is converted from Bitmap to JPG.

market, reduction in cost per print, greater reach, and piracy control.

tioned three processes are shown in **Figure 1**.

where imperceptibility is the main goal [45].

simple watermarking scheme.

*DOI: http://dx.doi.org/10.5772/intechopen.92412*

*A Survey on Piracy Protection Techniques in Digital Cinema Watermarking Schemes DOI: http://dx.doi.org/10.5772/intechopen.92412*

**Figure 1.** *A typical digital cinema system.*

*Recent Trends in Communication Networks*

[28] have been studied by researchers.

lems in the area of digital cinema rights management.

cinema. These problems are explained in the following.

cinema should be specifically resistant against these distortions.

watermarking schemes to be able to calculate distance and angle.

The second problem is to locate the seat on which the camcorder has been recording. This problem is to be solved by cinema holders as they are legally responsible for illegally recorded copies. Solving this problem requires digital cinema

There are some surveys on techniques used to solve the two problems mentioned above. But, they are outdated for such a fast-growing area [42, 43]. This motivates our work in this chapter, which is a comparative review on watermarking schemes used in digital cinema and the methods used by these schemes in order to achieve

The rest of this chapter is organized as follows. Section 2 presents an introduction to digital cinema. Section 3 discusses watermarking and related concepts. Section 4 presents a survey on watermarking in digital cinema. Section 5 concludes

Digital cinema refers to the set of processes, tools, and components which aim at the preparation, transmission, and projection of digital movies in cinema. This system is taking the place of traditional cinema which depends on reels of film

In digital cinema, 2K (2048 × 1080 or 2.2 megapixels) or 4K (4096 × 2160 or 8.8

Different aspects of security in CDNs such as privacy [24], digital property management [25], intrusion detection [26], trust [27], and eavesdropping protection

Digital property management and especially counterfeit protection mostly depend on watermarking in a variety of environments [37–39]. Digital watermarking has been finding its applications in digital cinema in recent years [40, 41]. But, there is a delicate challenge faced by watermarking systems used in digital cinema. In the absence of proper protective measures, counterfeit copies of movies can be recorded by handheld cameras in the cinema hall. Movie theater holders are obliged to take preventive measures in this regard. This creates two problems, which need to be taken into consideration while designing watermarking schemes for digital

The first problem is faced by movie providers. When a pirate copy is distributed, providers would like to identify the theatre where the copy has been recorded. Then they can sue the identified theatres as they have not fulfilled their legal obligations. One way to approach this problem is to add watermarks to the movie by the projector in projection time. This watermark carries some identification information about the cinema hall as well as the projection time. This makes it possible to identify the hall in which a counterfeit copy has been recorded. But, the distortions made by hand vibrations and point of view angle, makes it difficult to recover the watermark from the movie. Thus, watermarking schemes designed for digital

Digital cinema is a service that can be provided using CDNs. It is an online video streaming and projection service gaining a research focus in recent years [29–31]. Security is a serious challenge in digital cinema [32–34] like other services provided over CDNs. One of the most important aspects of digital cinema security is digital rights management [35, 36], which is about preserving the publication rights for the generator of contents. Counterfeit protection is one of the most challenging prob-

**12**

the mentioned goals.

**2. Digital cinema**

the chapter and suggests further research.

being projected by film projectors.

megapixels) resolutions are commonly used.

Among the advantages of digital cinema, we can point out reduction in time to market, reduction in cost per print, greater reach, and piracy control.

A digital cinema system consists of three main processes. In the first process, the film is converted to a digital print called DCP (Digital Cinema Package). The DCP is then delivered to the theatres and ingested (stored) by the related servers. This can be done through physical transportation of hard disks or through a digital distribution system. A content delivery network can serve to this purpose [44]. The DCP is often encrypted, and the keys required to decrypt the file are ingested in the screening tools to prevent theater owners from illegal screen extensions. In the third process, the movie is played back using a digital video projector. The aforementioned three processes are shown in **Figure 1**.

The first system specification for digital cinema was published in 2005 by a consortium of six major studios. This specification is referred to as DCI (Digital Cinema Initiatives) and uses JPG 2000 video encoding with XML playback standard.

#### **3. Digital watermarking**

Watermarking is a copyright ownership identification method used for noisetolerant media such as video, image, and audio. In this technique, an intentional noise is added to the signal in the form of covertly embedded information. In most cases, the hidden information is normally not perceptible. Rather it requires some revealing process to be extracted from the carrying content file. However, in some cases, it can be perceptible. For example, it can be visibly added to a film or image in order to encourage the user to buy the original version without the mark.

The hidden information should be robust (resistant) against simple modifications normally used to the media type. For example, a marker hidden in an image should not be removed when the image is converted from Bitmap to JPG.

Steganographic techniques such as watermarking and steganography are evaluated using measures like robustness, imperceptibility, and capacity. In watermarking, the main objective is robustness. It should not be confused with steganography where imperceptibility is the main goal [45].

**Figure 2** shows how the character "a" can be watermarked in a video using a simple watermarking scheme.

**Figure 2.** *Watermarking the character "a" in a movie.*

In the example shown in **Figure 2**, the video is first decomposed into **n** segments. Then two different variants of the video represented by *A* and **B** are prepared which are imperceptibly different in each segment. Each segment can be chosen from the variant *A* or *B*. The choice of *A* for a segment watermarks the bit value "**0,**" and choosing **B** means watermarking "1." In this example, the ASCII code "**01000001**" assigned to the character "*a*" has been watermarked to the video by choosing segments **2** and **8** from the variant **B** and the others from *A*.

#### **4. Survey on watermarking in digital cinema**

Illegal recording from the cinema screen using handheld cameras is a serious problem encountered by film makers. Watermarking, as a fingerprinting method aiming at piracy protection is a promising method for attacking this problem in the context of digital cinema. The watermarking process can be performed in show time and embed information regarding the projector and the playback time into the video. Since theatre owners are obliged to prevent handheld cameras in their premises, they are responsible for the pirate copies, and the watermark extracted from the pirate copies can specify the theatre where the copy has been recorded.

One of the most serious problems in the application of watermarking in digital cinema is that perspective, zoom, and some other parameters can be changed by the handheld camera, which leads to geometrical distortions. These distortions make it difficult to recover the watermark. This problem is faced by movie providers as they need to identify the theatre from which the pirate copy has been recorded. A watermarking system should guarantee distortion resistance in order to be capable of being used in digital cinema. In fact, old correlation-based watermark schemes are unable to prevent piracy because they are not robust to geometric distortions created by the handheld camera [46, 47].

The second challenge, which is faced by theatre owners, is locating the pirate in the theatre. Since theatre owners are sued when a pirate copy is distributed, they need mechanisms to identify the person who has recorded the illegal copy. To do this, they need to locate the camcorder. This way, they can identify the criminal using their ticket databases. This raises the need for watermarking methods capable of locating the camcorder.

The two aforementioned challenges have been part of the topic in several research works since early 2000s [48, 49], and they are still considered as research concerns in this area [42, 50]. In the following, we separately review the methods used by different watermarking schemes in order to attack each of the problems.

**15**

*A Survey on Piracy Protection Techniques in Digital Cinema Watermarking Schemes*

geometric process while storing or detecting the watermark.

In this section, we study the methods used in order to identify the theatres wherein hand camera copies are recorded. These methods mainly depend on

One solution to the aforementioned problem is to design methods which use only the temporal access to embed the watermark. A watermarking scheme of this kind was proposed in [51, 52], which modifies the mean luminance value in each frame of the video according to the samples of the watermark. In this research report, it has been taken into consideration that the human visual system is sensitive to flickers in low spatial frequencies. Thus, the proposed scheme attempts at avoiding this kind of flickers. To do this, the same watermark is applied to a certain

In the aforementioned scheme, the watermark is considered as a pseudo-random

sequence of length *n* consisting of **1** and *−***1** values. Embedding the watermark causes the luminance of each pixel to increase or decrease. But the change depends on a local scaling factor which has higher values for moving textual areas and lower values for non-moving flat areas. This scaling factor is defined as the minimum of a spatial scaling factor and a motion scaling factor. Moreover, there is a maximum

The motion scaling factor for each pixel is calculated as the difference from the corresponding pixel in the previous frame. On the other hand, the spatial scaling factor is calculated using a Laplacian filter. **Figure 3** shows this watermark-

In **Figure 3**, *TTexture* and *TTexture* are predefined thresholds and ∣*ABS*∣ represents the absolute operator. Moreover, **0** *≤ q <* **1***, k* is the number of the frame among the selected set of consecutive frames for embedding the watermark, and *K* is the

The authors of this report successfully tested the robustness of their watermark under several conditions such as changing the zoom and angle of the camera in addition to handheld camera recording and people walking between the camera and

Compensation is another solution to the geometrical distortion problem. In this method, a pre-process is used to restore the geometrical distortions before watermark extraction. A method based on compensation was proposed in [53]. The authors of this report made a simplifying assumption in order to make it easier to model the nonlinear distortions. They assumed that the handheld camera is located far from the screen at the back of the movie theatre but not so far from the center line of theatre. The authors of [53] present a parameterized mathematical model that compares the pirate copy with its original in a general case. For each specific pair of pirateoriginal pair, the compensation method tries to find the values for the parameters such that the model best matches the case. They modeled the distortions with four

• Affine transformations: there is assumed to be six degrees of parameters for this kind of transformations, which model rescaling (zooming), translation

*DOI: http://dx.doi.org/10.5772/intechopen.92412*

**4.1 Identifying the theatre**

*4.1.1 Temporal watermarking*

number of consequent frames.

number of consecutive frames.

ing scheme.

the screen.

*4.1.2 Compensation*

allowable change that cannot be violated.

mathematical transformations as follows.

*A Survey on Piracy Protection Techniques in Digital Cinema Watermarking Schemes DOI: http://dx.doi.org/10.5772/intechopen.92412*

#### **4.1 Identifying the theatre**

*Recent Trends in Communication Networks*

*Watermarking the character "a" in a movie.*

In the example shown in **Figure 2**, the video is first decomposed into **n** segments. Then two different variants of the video represented by *A* and **B** are prepared which are imperceptibly different in each segment. Each segment can be chosen from the variant *A* or *B*. The choice of *A* for a segment watermarks the bit value "**0,**" and choosing **B** means watermarking "1." In this example, the ASCII code "**01000001**" assigned to the character "*a*" has been watermarked to the video by

Illegal recording from the cinema screen using handheld cameras is a serious problem encountered by film makers. Watermarking, as a fingerprinting method aiming at piracy protection is a promising method for attacking this problem in the context of digital cinema. The watermarking process can be performed in show time and embed information regarding the projector and the playback time into the video. Since theatre owners are obliged to prevent handheld cameras in their premises, they are responsible for the pirate copies, and the watermark extracted from the pirate copies can specify the theatre where the copy has been

One of the most serious problems in the application of watermarking in digital cinema is that perspective, zoom, and some other parameters can be changed by the handheld camera, which leads to geometrical distortions. These distortions make it difficult to recover the watermark. This problem is faced by movie providers as they need to identify the theatre from which the pirate copy has been recorded. A watermarking system should guarantee distortion resistance in order to be capable of being used in digital cinema. In fact, old correlation-based watermark schemes are unable to prevent piracy because they are not robust to geometric distortions

The second challenge, which is faced by theatre owners, is locating the pirate in the theatre. Since theatre owners are sued when a pirate copy is distributed, they need mechanisms to identify the person who has recorded the illegal copy. To do this, they need to locate the camcorder. This way, they can identify the criminal using their ticket databases. This raises the need for watermarking methods capable

The two aforementioned challenges have been part of the topic in several research works since early 2000s [48, 49], and they are still considered as

research concerns in this area [42, 50]. In the following, we separately review the methods used by different watermarking schemes in order to attack each of the

choosing segments **2** and **8** from the variant **B** and the others from *A*.

**4. Survey on watermarking in digital cinema**

created by the handheld camera [46, 47].

of locating the camcorder.

**14**

problems.

recorded.

**Figure 2.**

In this section, we study the methods used in order to identify the theatres wherein hand camera copies are recorded. These methods mainly depend on geometric process while storing or detecting the watermark.

#### *4.1.1 Temporal watermarking*

One solution to the aforementioned problem is to design methods which use only the temporal access to embed the watermark. A watermarking scheme of this kind was proposed in [51, 52], which modifies the mean luminance value in each frame of the video according to the samples of the watermark. In this research report, it has been taken into consideration that the human visual system is sensitive to flickers in low spatial frequencies. Thus, the proposed scheme attempts at avoiding this kind of flickers. To do this, the same watermark is applied to a certain number of consequent frames.

In the aforementioned scheme, the watermark is considered as a pseudo-random sequence of length *n* consisting of **1** and *−***1** values. Embedding the watermark causes the luminance of each pixel to increase or decrease. But the change depends on a local scaling factor which has higher values for moving textual areas and lower values for non-moving flat areas. This scaling factor is defined as the minimum of a spatial scaling factor and a motion scaling factor. Moreover, there is a maximum allowable change that cannot be violated.

The motion scaling factor for each pixel is calculated as the difference from the corresponding pixel in the previous frame. On the other hand, the spatial scaling factor is calculated using a Laplacian filter. **Figure 3** shows this watermarking scheme.

In **Figure 3**, *TTexture* and *TTexture* are predefined thresholds and ∣*ABS*∣ represents the absolute operator. Moreover, **0** *≤ q <* **1***, k* is the number of the frame among the selected set of consecutive frames for embedding the watermark, and *K* is the number of consecutive frames.

The authors of this report successfully tested the robustness of their watermark under several conditions such as changing the zoom and angle of the camera in addition to handheld camera recording and people walking between the camera and the screen.

#### *4.1.2 Compensation*

Compensation is another solution to the geometrical distortion problem. In this method, a pre-process is used to restore the geometrical distortions before watermark extraction. A method based on compensation was proposed in [53]. The authors of this report made a simplifying assumption in order to make it easier to model the nonlinear distortions. They assumed that the handheld camera is located far from the screen at the back of the movie theatre but not so far from the center line of theatre.

The authors of [53] present a parameterized mathematical model that compares the pirate copy with its original in a general case. For each specific pair of pirateoriginal pair, the compensation method tries to find the values for the parameters such that the model best matches the case. They modeled the distortions with four mathematical transformations as follows.

• Affine transformations: there is assumed to be six degrees of parameters for this kind of transformations, which model rescaling (zooming), translation (shifting caused by shakes of the camera), rotation (caused by the angle of the camera), and shearing (caused by cropping).


They tested their method via simulating a handheld camera. The simulation process applies a curved-bilinear transformation along with converting from 1920 × 1980 resolution to 1024 × 576 and then cropping to 720 × 576. **Figure 4** shows this transformation. Their method successfully recovered a 64-bit watermark from the transformed video.

**Figure 3.**

*The watermarking scheme presented in [51, 52].*

**17**

**Figure 5.**

*A Survey on Piracy Protection Techniques in Digital Cinema Watermarking Schemes*

original video and it is robust to a variety of signal processing transforms.

A hardware-based watermarking scheme named "Additional Watermarking" was presented in [54–56], which does not require the original movie for the recovery of the watermark. This method uses DWT (Discrete Wavelet Transform) instead of the Laplacian transforms. In this scheme, watermarks are added to the video in both the encoding and the decoding processes. This method uses CRC32 as a hash function for selecting random places in the video to embed the watermark. This method places the mark in the lowest frequency components of the video. It was shown in the research that the proposed method does not make any perceptible change in the

The problem of tradeoff between fidelity and robustness was posed in [57]. A watermarking scheme based on STDM (Spread Transform Dither Modulation) was proposed in this research which uses the HVS (Human Visual System) properties of wavelet in order to resolve the tradeoff. These properties include the following facts.

• HVS is less sensitive to changes to very high or very low brightness portions of

• HVS is not very sensitive to changes in highly textured portions unless they are

In this scheme, the watermark is embedded during the JPEG2000 decoding phase. **Figure 5** shows a screen shot from Big Buck Bunny film before and after

In [53] another application for watermarking in digital cinema was proposed. This report proposes a watermarking method based on spread spectrum. This method is not only robust to geometric distortions, but also able to estimate the position of the handheld camera that has recorded the pirate copy. This may help

identifying the ticket number and the credit card number of the person.

*A screenshot from Big Buck Bunny before and after watermarking (Courtesy to [57]).*

• Noise in high resolution bands is not clearly perceptible to human eyes.

*DOI: http://dx.doi.org/10.5772/intechopen.92412*

*4.1.4 Spread transform dither modulation*

the video.

close to the borders.

watermarking with this method.

*4.1.5 Spread spectrum watermarking*

*4.1.3 Hardware-based additional watermarking*

**Figure 4.** *The curved-bilinear transformation in [48].*

#### *4.1.3 Hardware-based additional watermarking*

*Recent Trends in Communication Networks*

transformed video.

camera), and shearing (caused by cropping).

quadrilateral with eight degrees of freedom.

transform as well as the curved transform.

impacts of the lens properties such as short focal length.

(shifting caused by shakes of the camera), rotation (caused by the angle of the

• Bilinear transform: this kind of transform can convert a square to an ordinary

• Curved transform: tt is a simple mathematical transform that models the

• Curved-bilinear transform: it has been designed to compensate the bilinear

They tested their method via simulating a handheld camera. The simulation process applies a curved-bilinear transformation along with converting from 1920 × 1980 resolution to 1024 × 576 and then cropping to 720 × 576. **Figure 4** shows this transformation. Their method successfully recovered a 64-bit watermark from the

**16**

**Figure 4.**

**Figure 3.**

*The curved-bilinear transformation in [48].*

*The watermarking scheme presented in [51, 52].*

A hardware-based watermarking scheme named "Additional Watermarking" was presented in [54–56], which does not require the original movie for the recovery of the watermark. This method uses DWT (Discrete Wavelet Transform) instead of the Laplacian transforms. In this scheme, watermarks are added to the video in both the encoding and the decoding processes. This method uses CRC32 as a hash function for selecting random places in the video to embed the watermark. This method places the mark in the lowest frequency components of the video. It was shown in the research that the proposed method does not make any perceptible change in the original video and it is robust to a variety of signal processing transforms.

#### *4.1.4 Spread transform dither modulation*

The problem of tradeoff between fidelity and robustness was posed in [57]. A watermarking scheme based on STDM (Spread Transform Dither Modulation) was proposed in this research which uses the HVS (Human Visual System) properties of wavelet in order to resolve the tradeoff. These properties include the following facts.


In this scheme, the watermark is embedded during the JPEG2000 decoding phase. **Figure 5** shows a screen shot from Big Buck Bunny film before and after watermarking with this method.

#### *4.1.5 Spread spectrum watermarking*

In [53] another application for watermarking in digital cinema was proposed. This report proposes a watermarking method based on spread spectrum. This method is not only robust to geometric distortions, but also able to estimate the position of the handheld camera that has recorded the pirate copy. This may help identifying the ticket number and the credit card number of the person.

**Figure 5.** *A screenshot from Big Buck Bunny before and after watermarking (Courtesy to [57]).*

The method proposed in [58] embeds the watermark in the payload in a way that the geometric transformation applied by the handheld camera can be identified in addition to the position of the camera. This method requires the watermark payload to follow a periodic pattern. A basic pattern is generated using a secret key in a way that it follows a periodic Gaussian distribution with the mean equal to zero and the variance equal to one. Then the payload, which contains the serial number of the projector as well as a time stamp is embedded into the video after the modulation process using an additive spread-spectrum method.

The authors of [58] tested the accuracy of their method in a small seminar room as well as a large auditorium. The mean absolute error was at maximum 6.87 cm for the small-scale test and 50.38 cm for the large-scale test.

Another watermarking scheme based on spread spectrum techniques was introduced in [59]. This method stores the watermark in the YCbCr color space using translation, rotation, scaling or composite operations.

**Table 1** compares the methods used to identify the theatre. The parameters used in this comparison are as follows.


One point to note here is that the distortion factors studied in **Table 1** are not the only factors that make it complex to recover the projection time watermark from pirate copies. For example, it was shown in [60] that the lamination flickers, induced by the interplay between an LCD and a camcorder can cause some difficulties in the recovery of the watermark. In addition to temporal luminance variations studied in [60], spatial luminance variations induced by camcorder recording have been studied in [61].

#### **4.2 Locating the camcorder**

In this section, we study the methods that can be used by cinema owners in order to locate the pirate camera.


**19**

*A Survey on Piracy Protection Techniques in Digital Cinema Watermarking Schemes*

An approach to estimating the camcorder location has been proposed in [62]. In this method, unlike previous methods, audio is watermarked in the movie soundtrack instead of images, numbers or text messages being watermarked in the video itself. Most of the methods introduced in the literature avoid audio watermarking because of its complexity. In fact, it is difficult to hide any audio in soundtracks as they contain different types of audio such as voices, sound effects,

The method proposed in [62] depends on a stochastic analysis in the watermark detection process. This method uses the audio watermarking technique introduced in [63]. The idea behind this method is that the attenuation of an audio signal depends on the distance. Thus, a few watermarked audio signals played from different locations can provide adequate information for locating the pirate. The advantage of this method is that audio is not prone to geometric distortion.

Some recent research works such as the one reported in [50] have combined video watermarking and audio watermarking in order to achieve the advantages of both methods. Audio watermarking is not affected by geometric distortions resulting from perspective, zoom, and vibrations. On the other hand, video watermarking is not affected by distance. Thus, it looks pertinent to combine them to achieve

In the method proposed in [50], audio is watermarked in the video itself instead

In this chapter, we introduced the challenges faced by watermarking schemes in digital cinema. Then, we presented a review on watermarking methods specifically designed to confront these challenges. We focused on two main problems, first of which is the geometric distortion problem which and the second is camcorder location estimation. Our work in this chapter can be continued by studying other

of the soundtrack. This way, there is no need for the watermarked audio to be

watermarked in the soundtrack and in the movie itself.

security and performance aspects of digital cinema.

Another hybrid audio-video watermarking scheme was introduced in [64]. In this method unlike the one presented in [50], audio and video are separately

*DOI: http://dx.doi.org/10.5772/intechopen.92412*

*4.2.2 Hybrid audio-video watermarking*

played from different sources.

*4.2.1 Audio watermarking*

and music.

better results.

**5. Conclusion**

**Table 1.**

*A comparison among watermarking schemes used in digital cinema.*

*A Survey on Piracy Protection Techniques in Digital Cinema Watermarking Schemes DOI: http://dx.doi.org/10.5772/intechopen.92412*

#### *4.2.1 Audio watermarking*

*Recent Trends in Communication Networks*

process using an additive spread-spectrum method.

the small-scale test and 50.38 cm for the large-scale test.

translation, rotation, scaling or composite operations.

in this comparison are as follows.

• Resistance against hand vibrations

• Resistance against perspective drifts

the handheld camera and the screen

• Resistance against zoom changes

been studied in [61].

**4.2 Locating the camcorder**

order to locate the pirate camera.

*A comparison among watermarking schemes used in digital cinema.*

The method proposed in [58] embeds the watermark in the payload in a way that the geometric transformation applied by the handheld camera can be identified in addition to the position of the camera. This method requires the watermark payload to follow a periodic pattern. A basic pattern is generated using a secret key in a way that it follows a periodic Gaussian distribution with the mean equal to zero and the variance equal to one. Then the payload, which contains the serial number of the projector as well as a time stamp is embedded into the video after the modulation

The authors of [58] tested the accuracy of their method in a small seminar room as well as a large auditorium. The mean absolute error was at maximum 6.87 cm for

Another watermarking scheme based on spread spectrum techniques was introduced in [59]. This method stores the watermark in the YCbCr color space using

**Table 1** compares the methods used to identify the theatre. The parameters used

• Resistance against obstacles such as people's heads or people walking between

One point to note here is that the distortion factors studied in **Table 1** are not the only factors that make it complex to recover the projection time watermark from pirate copies. For example, it was shown in [60] that the lamination flickers, induced by the interplay between an LCD and a camcorder can cause some difficulties in the recovery of the watermark. In addition to temporal luminance variations studied in [60], spatial luminance variations induced by camcorder recording have

In this section, we study the methods that can be used by cinema owners in

Presented in [51, 52] [53] [54–56] [57] [58, 59]

**Method**

**transform**

**Spread spectrum**

**Temporal Compensation Additional Spread** 

Vibration NO NO YES YES NO Angle YES YES YES YES YES Obstacles YES YES YES YES YES Zoom YES YES YES YES YES

**18**

**Table 1.**

Robust Against

An approach to estimating the camcorder location has been proposed in [62]. In this method, unlike previous methods, audio is watermarked in the movie soundtrack instead of images, numbers or text messages being watermarked in the video itself. Most of the methods introduced in the literature avoid audio watermarking because of its complexity. In fact, it is difficult to hide any audio in soundtracks as they contain different types of audio such as voices, sound effects, and music.

The method proposed in [62] depends on a stochastic analysis in the watermark detection process. This method uses the audio watermarking technique introduced in [63]. The idea behind this method is that the attenuation of an audio signal depends on the distance. Thus, a few watermarked audio signals played from different locations can provide adequate information for locating the pirate. The advantage of this method is that audio is not prone to geometric distortion.

#### *4.2.2 Hybrid audio-video watermarking*

Some recent research works such as the one reported in [50] have combined video watermarking and audio watermarking in order to achieve the advantages of both methods. Audio watermarking is not affected by geometric distortions resulting from perspective, zoom, and vibrations. On the other hand, video watermarking is not affected by distance. Thus, it looks pertinent to combine them to achieve better results.

In the method proposed in [50], audio is watermarked in the video itself instead of the soundtrack. This way, there is no need for the watermarked audio to be played from different sources.

Another hybrid audio-video watermarking scheme was introduced in [64]. In this method unlike the one presented in [50], audio and video are separately watermarked in the soundtrack and in the movie itself.

#### **5. Conclusion**

In this chapter, we introduced the challenges faced by watermarking schemes in digital cinema. Then, we presented a review on watermarking methods specifically designed to confront these challenges. We focused on two main problems, first of which is the geometric distortion problem which and the second is camcorder location estimation. Our work in this chapter can be continued by studying other security and performance aspects of digital cinema.

*Recent Trends in Communication Networks*

#### **Author details**

Behrouz Zolfaghari† and Pinaki Mitra\* Department of Computer Science and Engineering, Indian Institute of Technology Guwahati, India

\*Address all correspondence to: pinaki@iitg.ac.in

† Equally contributed.

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**21**

*A Survey on Piracy Protection Techniques in Digital Cinema Watermarking Schemes*

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1980;**9**:951-962

Sciences; 2003

Supply; 2009

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*A Survey on Piracy Protection Techniques in Digital Cinema Watermarking Schemes DOI: http://dx.doi.org/10.5772/intechopen.92412*

#### **References**

*Recent Trends in Communication Networks*

**20**

**Author details**

Guwahati, India

Behrouz Zolfaghari†

† Equally contributed.

and Pinaki Mitra\*

\*Address all correspondence to: pinaki@iitg.ac.in

provided the original work is properly cited.

Department of Computer Science and Engineering, Indian Institute of Technology

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

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[19] Chen M, Wang L, Chen J, Wei X, Lei L. A computing and content delivery network in the smart city: Scenario, framework, and analysis. IEEE Network. 2019;**33**(2):89-95

[20] Bilen T, Canberk B. Handoveraware content replication for mobile-CDN. IEEE Networking Letters. 2019;**1**(1):10-13

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[23] Taleb T, Frangoudis PA, Benkacem I, Ksentini A. CDN slicing over a multidomain edge cloud. IEEE Transactions on Mobile Computing (Early Access). 2019:1-1

[24] Cui S, Asghar MR, Russello G. Multi-CDN: Towards privacy in content delivery networks. IEEE Transactions on Dependable and Secure Computing (Early Access). 2018:1-1

[25] Chattopadhyay T, Sinha A, Hardikar A. H.264 compressed domain watermarking in content delivery network (CDN) environment. In: Proceedings of 2nd International Conference on Computational Intelligence, Communication Systems and Networks; 2010

[26] Fiadino P, D'Alconzo A, Bär A, Finamore A, Casas P. On the detection of network traffic anomalies in content delivery network services. In: Proceedings of 6th International Teletraffic Congress (ITC); 2014

[27] Li S, Doh I, Chae K. Non-redundant indirect trust search algorithm based on a cross-domain trust model in content delivery network. In: Proceedings of 19th International Conference on Advanced Communication Technology (ICACT); 2017

[28] Huang T-C, Shieh C-K, Miao Y-B. Java Application's Packet Eavesdropper for content delivery network. In: Proceedings of International Conference on Advanced Information Networking and Applications (AINA); 2005

[29] Boitard R, Jacquemin J-P, Damberg G, Stojmenovik G, Ballestad A. Evaluation of color pixel representations for high dynamic range digital cinema. SMPTE Motion Imaging Journal. 2018;**127**(2):46-56

[30] Gong B, Qin H, Chen D, Wang F. A study of stereoscopic digital cinema in china including new standards and recommendations. SMPTE Motion Imaging Journal. 2016;**125**(3):1-7

[31] Schuck M, Ludé P. An analysis of system contrast in digital cinema

**23**

*A Survey on Piracy Protection Techniques in Digital Cinema Watermarking Schemes*

comparison. International Journal of Computer, Electrical, Automation, Control and Information Engineering.

[42] Dubey NK, Modi H. Comparatives study of various techniques against camcorder piracy in theater. In: 6th International Conference on Multimedia Computing and Systems

[43] Dubey NK, Kumar S. A review of watermarking application in digital cinema for piracy deterrence. In: ourth International Conference on Communication Systems and Network

Charvillat V. The DCP bay: Toward an art-house content delivery network for digital cinema. In: Proceedings of 7th International Conference on Advances in Multimedia (MMEDIA); 2015

2017;**11**(2):256-261

(ICMCS); 2018

Technologies; 2014

[44] Bertrand N, Durou J-D,

[45] Sharifzadeh M, Aloraini M,

and Security. 2020;**15**:867-879

for broadcast monitoring. In:

Schonfeld D. Adaptive batch size image merging steganography and quantized gaussian image steganography. IEEE Transactions on Information Forensics

[46] Kalker T, Depovere D, Haitsma J, Maes M. A video watermarking system

Proceedings of IS&T/SPIE/EI25; 1999

[47] Bender W, Gruhl D, Morimoto N. Techniques for data hiding. In: Proceedings of the SPIE; 1995

[48] Lubin J, Bloom JA, Cheng H. Robust content-dependent highfidelity watermark for tracking in digital cinema. Proceedings of SPIE.

[49] Nguyen P, Balter R, Montfort N, Baudry S. Registration methods for nonblind watermark detection in digital cinema applications. Proceedings of

2003;**5020**(1):536-545

SPIE. 2003;**5020**(1):553-562

*DOI: http://dx.doi.org/10.5772/intechopen.92412*

auditoriums. SMPTE Motion Imaging

[32] Stone JJ. A new integrated system for digital cinema projection and security. In: Proceedings of The IEE 2-Day Seminar on IT to HD; 2004

[33] Bloom JA. Digital Cinema Content Security and the DCI. In: Proceedings of Annual Conference on Information

[34] Stone JJ, David MWA. An integrated system for digital cinema projection and security. SMPTE Motion Imaging

[35] Bloom JA. Security and rights management in digital cinema. In: Proceedings of IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP); 2003

[36] Bloom JA. Security and rights management in digital cinema. In: Proceedings of International Conference on Multimedia and Expo. (ICME); 2003

[38] Kricha Z, Kricha A, Sakly A. Accommodative extractor for QIMbased watermarking schemes. IET Image Processing. 2019;**13**(1):89-97

[39] Shayan M, Bhattacharjee S, Tang J, Chakrabarty K, Karri R. Bio-protocol watermarking on digital microfluidic biochips. IEEE Transactions on Information Forensics and Security.

[40] Shukla D, Sharma M. A novel scenebased video watermarking scheme for copyright protection. Journal of Intelligent Systems. 2017;**27**(1):47-66

[41] Kelkoul H, Zaz Y. Digital cinema watermarking state of art and

[37] Ma H, Jia C, Li S, Zheng W, Xmark W. Dynamic software watermarking using Collatz conjecture. IEEE Transactions on Information Forensics and Security.

Journal. 2016;**125**(4):40-49

Sciences and Systems; 2006

Journal. 2005;**114**:10-11

2019;**14**(11):2859-2874

2019;**14**(1):625-639

*A Survey on Piracy Protection Techniques in Digital Cinema Watermarking Schemes DOI: http://dx.doi.org/10.5772/intechopen.92412*

auditoriums. SMPTE Motion Imaging Journal. 2016;**125**(4):40-49

*Recent Trends in Communication Networks*

[15] Lo SW. Towards secure online distribution of multimedia codestreams [thesis]. Singapore: Management

[24] Cui S, Asghar MR, Russello G. Multi-CDN: Towards privacy in content delivery networks. IEEE Transactions on Dependable and Secure Computing

(Early Access). 2018:1-1

and Networks; 2010

(ICACT); 2017

[25] Chattopadhyay T, Sinha A,

Hardikar A. H.264 compressed domain watermarking in content delivery network (CDN) environment. In: Proceedings of 2nd International Conference on Computational

Intelligence, Communication Systems

[26] Fiadino P, D'Alconzo A, Bär A, Finamore A, Casas P. On the detection of network traffic anomalies in content delivery network services. In: Proceedings of 6th International Teletraffic Congress (ITC); 2014

[27] Li S, Doh I, Chae K. Non-redundant indirect trust search algorithm based on a cross-domain trust model in content delivery network. In: Proceedings of 19th International Conference on Advanced Communication Technology

[28] Huang T-C, Shieh C-K, Miao Y-B. Java Application's Packet Eavesdropper for content delivery network. In: Proceedings of

Information Networking and Applications (AINA); 2005

[29] Boitard R, Jacquemin J-P, Damberg G, Stojmenovik G,

Journal. 2018;**127**(2):46-56

International Conference on Advanced

Ballestad A. Evaluation of color pixel representations for high dynamic range digital cinema. SMPTE Motion Imaging

[30] Gong B, Qin H, Chen D, Wang F. A study of stereoscopic digital cinema in china including new standards and recommendations. SMPTE Motion Imaging Journal. 2016;**125**(3):1-7

[31] Schuck M, Ludé P. An analysis of system contrast in digital cinema

[16] Kuang J, Yu S-Z. Broadcast-based content delivery in information-centric hybrid multihop wireless networks. IEEE Communications Letters.

[17] Xiao X, Ahmed M, Chen X,

delivery via efficient resource allocation for network coding aided D2D communications. IEEE Access.

Zhao Y, Li Y, Han Z. Accelerating content

[18] Azogu IK, Ferreira MT, Liu H. A security metric for VANET content delivery. In: Proceedings of IEEE Global Communications Conference

[19] Chen M, Wang L, Chen J, Wei X, Lei L. A computing and content delivery network in the smart city: Scenario, framework, and analysis. IEEE Network. 2019;**33**(2):89-95

[20] Bilen T, Canberk B. Handoveraware content replication for mobile-CDN. IEEE Networking Letters.

[21] Al-Abbasi A, Aggarwal V, Lan T, Xiang Y, Ra M-R, Chen Y-F. Fasttrack: Minimizing stalls for cdn-based overthe-top video streaming systems. IEEE Transactions on Cloud Computing.

[22] Tang G, Wang H, Wu K, Guo D. Tapping the knowledge of dynamic traffic demands for optimal CDN design. IEEE/ACM Transactions on Networking. 2019;**27**(1):98-111

[23] Taleb T, Frangoudis PA, Benkacem I, Ksentini A. CDN slicing over a multidomain edge cloud. IEEE Transactions on Mobile Computing (Early Access).

University; 2016

2017;**21**(4):889-9892

2019;**7**:115783-115796

(GLOBECOM); 2012

2019;**1**(1):10-13

2019;**27**(2):835-847

**22**

2019:1-1

[32] Stone JJ. A new integrated system for digital cinema projection and security. In: Proceedings of The IEE 2-Day Seminar on IT to HD; 2004

[33] Bloom JA. Digital Cinema Content Security and the DCI. In: Proceedings of Annual Conference on Information Sciences and Systems; 2006

[34] Stone JJ, David MWA. An integrated system for digital cinema projection and security. SMPTE Motion Imaging Journal. 2005;**114**:10-11

[35] Bloom JA. Security and rights management in digital cinema. In: Proceedings of IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP); 2003

[36] Bloom JA. Security and rights management in digital cinema. In: Proceedings of International Conference on Multimedia and Expo. (ICME); 2003

[37] Ma H, Jia C, Li S, Zheng W, Xmark W. Dynamic software watermarking using Collatz conjecture. IEEE Transactions on Information Forensics and Security. 2019;**14**(11):2859-2874

[38] Kricha Z, Kricha A, Sakly A. Accommodative extractor for QIMbased watermarking schemes. IET Image Processing. 2019;**13**(1):89-97

[39] Shayan M, Bhattacharjee S, Tang J, Chakrabarty K, Karri R. Bio-protocol watermarking on digital microfluidic biochips. IEEE Transactions on Information Forensics and Security. 2019;**14**(1):625-639

[40] Shukla D, Sharma M. A novel scenebased video watermarking scheme for copyright protection. Journal of Intelligent Systems. 2017;**27**(1):47-66

[41] Kelkoul H, Zaz Y. Digital cinema watermarking state of art and

comparison. International Journal of Computer, Electrical, Automation, Control and Information Engineering. 2017;**11**(2):256-261

[42] Dubey NK, Modi H. Comparatives study of various techniques against camcorder piracy in theater. In: 6th International Conference on Multimedia Computing and Systems (ICMCS); 2018

[43] Dubey NK, Kumar S. A review of watermarking application in digital cinema for piracy deterrence. In: ourth International Conference on Communication Systems and Network Technologies; 2014

[44] Bertrand N, Durou J-D, Charvillat V. The DCP bay: Toward an art-house content delivery network for digital cinema. In: Proceedings of 7th International Conference on Advances in Multimedia (MMEDIA); 2015

[45] Sharifzadeh M, Aloraini M, Schonfeld D. Adaptive batch size image merging steganography and quantized gaussian image steganography. IEEE Transactions on Information Forensics and Security. 2020;**15**:867-879

[46] Kalker T, Depovere D, Haitsma J, Maes M. A video watermarking system for broadcast monitoring. In: Proceedings of IS&T/SPIE/EI25; 1999

[47] Bender W, Gruhl D, Morimoto N. Techniques for data hiding. In: Proceedings of the SPIE; 1995

[48] Lubin J, Bloom JA, Cheng H. Robust content-dependent highfidelity watermark for tracking in digital cinema. Proceedings of SPIE. 2003;**5020**(1):536-545

[49] Nguyen P, Balter R, Montfort N, Baudry S. Registration methods for nonblind watermark detection in digital cinema applications. Proceedings of SPIE. 2003;**5020**(1):553-562

[50] Kelkoul H, Zaz Y, Tribak H, Schaefer G. A robust combined audio and video watermark algorithm against cinema piracy. In: 6th International Conference on Multimedia Computing and Systems (ICMCS); 2018

[51] Kalker T, Haitsma J. A watermarking scheme for digital cinema. In: Proceedings of International Conference on Image Processing; 2001

[52] Van Leest A, Haitsma J, Kalker T. On digital cinema and watermarking. In: Proceedings of SPIE 5020; 2003

[53] Delannay D, Delaigle J-F, Barlaud M. Compensation of geometrical deformations for watermark extraction in the digital cinema application. In: Proceedings of SPIE Security and Watermarking of Multimedia Contents; 2003

[54] Vural S, Tomii H, Yamauchi H. Traceable robust watermarking for digital cinema system. In: Proceedings of International Symposium on Signal Processing and Its Applications; 2005

[55] Vural S, Tomii H, Yamauchi H. Video watermarking for digital cinema contents. In: Proceedings of European Signal Processing Conference; 2005

[56] Vural S, Tomii H, Yamauchi H. Robust digital cinema watermarking. International Journal of Computer and Information Engineering. 2008;**2**(10):3606-3611

[57] Darazi R, Callau P, Macq B. Secure and HVS-adaptive exhibition spread transform dither modulation watermarking for digital cinema. In: Proceedings of First IEEE International Workshop on Information Forensics and Security (WIFS); 2009:1-12

[58] Callau P, Darazi R, Macq B. Exhibition QIM-based watermarking for digital cinema. Proceedings of SPIE. 2009;**7254**(1):1-12

[59] Dubey NK, Kumar S. An effective approach of distortion-resistant video watermarking for piracy deterrence. International Journal of Security and Its Applications. 2015;**9**(1):283-294

**Chapter 3**

*Tri Ngo Minh*

**Abstract**

covering design

**1. Introduction**

**1.1 Confidentiality**

tion systems.

**25**

Confidentiality and Integrity for

This chapter discusses how to ensure confidentiality and integrity for data flow in IoT applications. While confidentiality could be assessed by access control, cryptography, or information flow analysis, integrity is still an open challenge. This chapter proposes to use error-correcting codes to guarantee integrity, i.e., to maintain and assure the errorless state of data. Besides errors, many communication channels also cause erasures, i.e., the receiver cannot decide which symbol the received waveform represents. The chapter proposes a method that might correct both errors and erasures together. Our method is efficient in reducing memory

**Keywords:** confidentiality, integrity, information flow, erasure, separating matrix,

It is estimated that Internet of Things (IoT) will generate billions of dollars in profit for industries over the next two decades. Many organizations have started to develop and implement their own IoT strategies. IoT enables devices would generate and transmit so many data such that security should be a top concern. IoT users require that communication technologies have to guarantee both efficiency and security. This chapter discusses how to guarantee two main properties of security,

Securing the data manipulated by information systems has been a challenge in the past few years. Several methods to limit the information disclosure have been proposed, such as *access control* and *cryptography*. These are useful approaches, i.e.,

*unauthorized* users. However, they still have a fundamental limitation, i.e., they do not regulate the information propagation after it has been released. For example, access control prevents unauthorized file access, but is insufficient to control how the data is used afterwards. Similarly, cryptography provides a shield to exchange information privately across a nonsecure channel, but no guarantee about the confidentiality of private data is given after it is decrypted. Thus, neither access control nor encryption provides a *complete* solution to protect confidentiality for informa-

they can prevent confidential information from being read or modified by

IoT/Mobile Networks

storage as well as decoding complexity.

i.e., *confidentiality* and *integrity*, for IoT applications.

[60] Hajj-Ahmad A, Baudry S, Chupeau B, Doerr G, Wu M. Flicker forensics for camcorder piracy. IEEE Transactions on Information Forensics and Security. 2017;**12**(1)

[61] Kelkoul H, Zaz Y. Registration methods for nonblind watermark detection in digital cinema applications. International Journal of Computer, Electrical, Automation, Control and Information Engineering. 2003;**11**(2):2107

[62] Nakashima Y, Tachibana R, Babaguchi N. Watermarked movie soundtrack finds the position of the camcorder in a theater. IEEE Transactions on Multimedia. 2009;**11**(3)

[63] Tachibana R, Shimizu S, Kobayashi S, Nakamura T. An audio watermarking method using a twodimensional psuedo-random array. Signal Processing. 2002;**82**(1):1455-1469

[64] Gosavi CS, Mali SN. Secure, robust video watermarking to prevent camcorder piracy. Indian Journal of Science and Technology. 2017;**10**(18):1-10

#### **Chapter 3**

*Recent Trends in Communication Networks*

[50] Kelkoul H, Zaz Y, Tribak H, Schaefer G. A robust combined audio and video watermark algorithm against cinema piracy. In: 6th International Conference on Multimedia Computing

and Systems (ICMCS); 2018

scheme for digital cinema. In:

on Image Processing; 2001

[53] Delannay D, Delaigle J-F, Barlaud M. Compensation of geometrical deformations for watermark extraction in the digital cinema application. In: Proceedings of SPIE Security and Watermarking of

Multimedia Contents; 2003

[54] Vural S, Tomii H, Yamauchi H. Traceable robust watermarking for digital cinema system. In: Proceedings of International Symposium on Signal Processing and Its Applications; 2005

[55] Vural S, Tomii H, Yamauchi H. Video watermarking for digital cinema contents. In: Proceedings of European Signal Processing Conference; 2005

[56] Vural S, Tomii H, Yamauchi H. Robust digital cinema watermarking. International Journal of Computer and Information Engineering.

[57] Darazi R, Callau P, Macq B. Secure

and HVS-adaptive exhibition spread transform dither modulation watermarking for digital cinema. In: Proceedings of First IEEE International Workshop on Information Forensics and

Security (WIFS); 2009:1-12

2009;**7254**(1):1-12

[58] Callau P, Darazi R, Macq B. Exhibition QIM-based watermarking for digital cinema. Proceedings of SPIE.

2008;**2**(10):3606-3611

[51] Kalker T, Haitsma J. A watermarking

[59] Dubey NK, Kumar S. An effective approach of distortion-resistant video watermarking for piracy deterrence. International Journal of Security and Its

Applications. 2015;**9**(1):283-294

[60] Hajj-Ahmad A, Baudry S, Chupeau B, Doerr G, Wu M. Flicker forensics for camcorder piracy. IEEE Transactions on Information Forensics

[61] Kelkoul H, Zaz Y. Registration methods for nonblind watermark detection in digital cinema applications. International Journal of Computer, Electrical, Automation, Control and Information Engineering.

[62] Nakashima Y, Tachibana R, Babaguchi N. Watermarked movie soundtrack finds the position of the camcorder in a theater. IEEE

[63] Tachibana R, Shimizu S, Kobayashi S, Nakamura T. An audio watermarking method using a twodimensional psuedo-random array. Signal Processing. 2002;**82**(1):1455-1469

[64] Gosavi CS, Mali SN. Secure, robust video watermarking to prevent camcorder piracy. Indian Journal of Science and Technology.

2017;**10**(18):1-10

Transactions on Multimedia. 2009;**11**(3)

and Security. 2017;**12**(1)

2003;**11**(2):2107

Proceedings of International Conference

[52] Van Leest A, Haitsma J, Kalker T. On digital cinema and watermarking. In: Proceedings of SPIE 5020; 2003

**24**

## Confidentiality and Integrity for IoT/Mobile Networks

*Tri Ngo Minh*

#### **Abstract**

This chapter discusses how to ensure confidentiality and integrity for data flow in IoT applications. While confidentiality could be assessed by access control, cryptography, or information flow analysis, integrity is still an open challenge. This chapter proposes to use error-correcting codes to guarantee integrity, i.e., to maintain and assure the errorless state of data. Besides errors, many communication channels also cause erasures, i.e., the receiver cannot decide which symbol the received waveform represents. The chapter proposes a method that might correct both errors and erasures together. Our method is efficient in reducing memory storage as well as decoding complexity.

**Keywords:** confidentiality, integrity, information flow, erasure, separating matrix, covering design

#### **1. Introduction**

It is estimated that Internet of Things (IoT) will generate billions of dollars in profit for industries over the next two decades. Many organizations have started to develop and implement their own IoT strategies. IoT enables devices would generate and transmit so many data such that security should be a top concern. IoT users require that communication technologies have to guarantee both efficiency and security. This chapter discusses how to guarantee two main properties of security, i.e., *confidentiality* and *integrity*, for IoT applications.

#### **1.1 Confidentiality**

Securing the data manipulated by information systems has been a challenge in the past few years. Several methods to limit the information disclosure have been proposed, such as *access control* and *cryptography*. These are useful approaches, i.e., they can prevent confidential information from being read or modified by *unauthorized* users. However, they still have a fundamental limitation, i.e., they do not regulate the information propagation after it has been released. For example, access control prevents unauthorized file access, but is insufficient to control how the data is used afterwards. Similarly, cryptography provides a shield to exchange information privately across a nonsecure channel, but no guarantee about the confidentiality of private data is given after it is decrypted. Thus, neither access control nor encryption provides a *complete* solution to protect confidentiality for information systems.

To ensure confidentiality for an information system, i.e., IoT system, it is necessary to show that the system *as a whole* enforces a confidentiality policy, i.e., by analysing how information flows within the system. The analysis must show that information controlled by a confidentiality policy cannot flow to a place where that policy is violated. Thus, the confidentiality policy we wish to enforce is an *information flow policy*, and the method that enforces them is an *information flow analysis*.

Error-correcting codes are often applied in telecommunications. Many early applications of coding were developed for deep-space and satellite communication systems. For example, signals from satellites and space crafts are sent back to earth. The channel for such transmission is space and the earth's atmosphere. These communication systems not only have limitations on their transmitted power, but also introduce errors, due to solar activity and atmospheric conditions, into weak signals. Error-correcting codes are an excellent method to guarantee the integrity of these communication links. With the applications of error-correcting codes, most of the data sent could be correctly decoded here on earth. As examples, a binary (32,6,16) Reed-Muller code was used during the Mariner and Viking mission to Mars around 1970 or a convolutional code was used on the Pioneer 10 and 11 missions to Jupiter and Saturn in 1972. The (24,12,8) Golay code was used in the Voyager 1 and Voyager 2 spacecrafts transmitting color pictures of Jupiter and Saturn in 1979 and 1980. When Voyager 2 went on to Uranus and Neptune, the code was switched to a concatenated Reed-Solomon code for its substantially more

The block and convolutional codes are also applied to the global system for mobile communications (GSM) which is the most popular digital cellular mobile communication system. Reed Solomon and Viterbi codes have been used for nearly 20 years for the delivery of digital satellite TV. Low-density parity-check codes (LDPC codes) are now used in many recent high-speed communication standards, such as Digital video broadcasting-S2 (DVB-S2), WiMAX, 10GBase-T Ethernet [9]. Most error correcting codes, in general, are designed to correct or detect errors.

However, many channels cause erasures, i.e., the demodulator cannot decide whether the received waveform represents bit 0 or 1, in addition to errors. Basically, decoding over such channels can be done by: firstly, deleting erased symbols and then, decoding the resulting vector with respect to the punctured code, i.e., the code in which all erasures have been removed. For any given linear code and any given maximum number of correctable erasures, in [7], Abdel-Ghaffar and Weber introduced a parity-check matrix yielding parity-check equations that do not check any of the erased symbols and which are sufficient to characterize the punctured code. This allows for the *separation* of erasures from errors to facilitate decoding. However, these parity-check matrices have too many redundant rows. To reduce decoding complexity, parity-check matrices with small number of rows are preferred. This chapter proposes a method that can build a matrix with a smaller

**Organization of the paper**: The rest of this chapter is organized as follows. Section 2 introduces the main ideas of error-correcting codes, errors and erasures. Section 3 presents methods to construct a parity-check matrix that can correct both errors and erasures. Section 4 discusses a general solution for the covering design,

Let *C* be an ½ � *n; k; d* linear block code. It means that *C* is a *k*-dimensional subspace of the *n*-dimensional vector space. The set of codewords of *C* can be defined as the

Since a vector **<sup>x</sup>** is a codeword of *<sup>C</sup>* iff **<sup>x</sup>***H<sup>T</sup>* <sup>¼</sup> 0, where the superscript *<sup>T</sup>* denotes the

of rank *<sup>n</sup>* � *<sup>k</sup>*.

which is used in the proposal. Finally, Section 5 concludes the chapter.

null space of the row space of an *r* � *n* parity-check matrix *H* ¼ *hi,j*

transpose, we can derive *r* parity-check equations PCE, as follows,

powerful error correcting capabilities.

*Confidentiality and Integrity for IoT/Mobile Networks DOI: http://dx.doi.org/10.5772/intechopen.88011*

number of rows.

**2. Codes, errors and erasures**

**2.1 Linear block codes**

**27**

Information flow analysis is a technique that has recently become an active research topic. In general, the approach of information flow security is based on the notion of *interference* [1]. Informally, *interference* exists inside a system when private data affect public data, e.g., an attacker might guess private data from observing public data. *Noninterference*, i.e., the absence of interference, is often used to prove that an information system is secured.

Noninterference is required for applications where the users need their private data strictly protected. However, many practical IoT applications might leak *minor* information. Such systems include password checkers, cryptographic operations, etc. For instance, when an attacker tries to guess the password: even when the attacker makes a wrong guess, secret information has been leaked, i.e., it reveals information about what the real password is not. Similarly, there is a flow of information from the plain-text to the cipher-text, since the cipher-text depends on the plain-text. These applications are rejected by the definition of noninterference.

However, the insecure property will happen only when it exceeds a specific threshold, or amount of interference. If the interference in the system is small enough, e.g., below a threshold given by specific security policy, the system is considered to be secure. The security analysis that requires to determine how much information flows from high level, i.e., secret data, to low level, i.e., public output, is known as *quantitative information flow*. It concerned with measure the leakage of information in order to decide if the leakage is tolerable.

*Qualitative* information flow analysis, i.e., noninterference, aims to determine whether a program leaks private information or not. Thus, these absolute security properties always reject a program if it leaks any information. *Quantitative* information flow analysis offers a more general security policy, since it gives a method to tolerate a minor leakage, i.e., by computing how much information has been leaked and comparing this with a threshold. By adjusting the threshold, the security policy can be applied for different applications, and in particular, if the threshold is 0, the quantitative policy is seen as a qualitative one. The idea of quantitative information flow analysis has been discussed in details in [2], one of our papers; readers can refer to it for more information.

#### **1.2 Integrity**

Integrity means maintaining and assuring accuracy and completeness of data. However, during the wireless transmission in IoT applications, messages can be erroneous due to many reasons, e.g., attenuation, distortion or the addition of noise. Error means the receiver cannot decode correctly the signal to get the right symbol. In order to protect data against errors, channel coding, i.e., error-correcting codes are required. Error-correcting codes ensure proper performance of IoT systems. They ensure the integrity of communication links in the presence of noise, distortion, and attenuation [3–6]. The use of a parity-bit as an error-detecting mechanism is one of the simplest and most well-known schemes used in digital communication. Data is portioned into blocks. To each block, an additional bit is appended to make the number of bits which are 1 in the block, including the appended bit, an even number. If a single bit-error occurs, within the block, the number of 1's becomes odd. Hence, this allows for detection of single errors [7, 8].

*Confidentiality and Integrity for IoT/Mobile Networks DOI: http://dx.doi.org/10.5772/intechopen.88011*

To ensure confidentiality for an information system, i.e., IoT system, it is necessary to show that the system *as a whole* enforces a confidentiality policy, i.e., by analysing how information flows within the system. The analysis must show that information controlled by a confidentiality policy cannot flow to a place where that policy is violated. Thus, the confidentiality policy we wish to enforce is an *information flow policy*, and the method that enforces them is an *information flow analysis*. Information flow analysis is a technique that has recently become an active research topic. In general, the approach of information flow security is based on the notion of *interference* [1]. Informally, *interference* exists inside a system when private data affect public data, e.g., an attacker might guess private data from observing public data. *Noninterference*, i.e., the absence of interference, is often used to prove

Noninterference is required for applications where the users need their private data strictly protected. However, many practical IoT applications might leak *minor* information. Such systems include password checkers, cryptographic operations, etc. For instance, when an attacker tries to guess the password: even when the attacker makes a wrong guess, secret information has been leaked, i.e., it reveals information about what the real password is not. Similarly, there is a flow of information from the plain-text to the cipher-text, since the cipher-text depends on the plain-text. These applications are rejected by the definition of noninterference. However, the insecure property will happen only when it exceeds a specific threshold, or amount of interference. If the interference in the system is small enough, e.g., below a threshold given by specific security policy, the system is considered to be secure. The security analysis that requires to determine how much information flows from high level, i.e., secret data, to low level, i.e., public output, is known as *quantitative information flow*. It concerned with measure the leakage of

*Qualitative* information flow analysis, i.e., noninterference, aims to determine whether a program leaks private information or not. Thus, these absolute security properties always reject a program if it leaks any information. *Quantitative* information flow analysis offers a more general security policy, since it gives a method to tolerate a minor leakage, i.e., by computing how much information has been leaked and comparing this with a threshold. By adjusting the threshold, the security policy can be applied for different applications, and in particular, if the threshold is 0, the quantitative policy is seen as a qualitative one. The idea of quantitative information flow analysis has been discussed in details in [2], one of our papers; readers can

Integrity means maintaining and assuring accuracy and completeness of data. However, during the wireless transmission in IoT applications, messages can be erroneous due to many reasons, e.g., attenuation, distortion or the addition of noise. Error means the receiver cannot decode correctly the signal to get the right symbol. In order to protect data against errors, channel coding, i.e., error-correcting codes are required. Error-correcting codes ensure proper performance of IoT systems. They ensure the integrity of communication links in the presence of noise, distortion, and attenuation [3–6]. The use of a parity-bit as an error-detecting mechanism is one of the simplest and most well-known schemes used in digital communication. Data is portioned into blocks. To each block, an additional bit is appended to make the number of bits which are 1 in the block, including the appended bit, an even number. If a single bit-error occurs, within the block, the number of 1's becomes

that an information system is secured.

*Recent Trends in Communication Networks*

refer to it for more information.

**1.2 Integrity**

**26**

information in order to decide if the leakage is tolerable.

odd. Hence, this allows for detection of single errors [7, 8].

Error-correcting codes are often applied in telecommunications. Many early applications of coding were developed for deep-space and satellite communication systems. For example, signals from satellites and space crafts are sent back to earth. The channel for such transmission is space and the earth's atmosphere. These communication systems not only have limitations on their transmitted power, but also introduce errors, due to solar activity and atmospheric conditions, into weak signals. Error-correcting codes are an excellent method to guarantee the integrity of these communication links. With the applications of error-correcting codes, most of the data sent could be correctly decoded here on earth. As examples, a binary (32,6,16) Reed-Muller code was used during the Mariner and Viking mission to Mars around 1970 or a convolutional code was used on the Pioneer 10 and 11 missions to Jupiter and Saturn in 1972. The (24,12,8) Golay code was used in the Voyager 1 and Voyager 2 spacecrafts transmitting color pictures of Jupiter and Saturn in 1979 and 1980. When Voyager 2 went on to Uranus and Neptune, the code was switched to a concatenated Reed-Solomon code for its substantially more powerful error correcting capabilities.

The block and convolutional codes are also applied to the global system for mobile communications (GSM) which is the most popular digital cellular mobile communication system. Reed Solomon and Viterbi codes have been used for nearly 20 years for the delivery of digital satellite TV. Low-density parity-check codes (LDPC codes) are now used in many recent high-speed communication standards, such as Digital video broadcasting-S2 (DVB-S2), WiMAX, 10GBase-T Ethernet [9].

Most error correcting codes, in general, are designed to correct or detect errors. However, many channels cause erasures, i.e., the demodulator cannot decide whether the received waveform represents bit 0 or 1, in addition to errors. Basically, decoding over such channels can be done by: firstly, deleting erased symbols and then, decoding the resulting vector with respect to the punctured code, i.e., the code in which all erasures have been removed. For any given linear code and any given maximum number of correctable erasures, in [7], Abdel-Ghaffar and Weber introduced a parity-check matrix yielding parity-check equations that do not check any of the erased symbols and which are sufficient to characterize the punctured code. This allows for the *separation* of erasures from errors to facilitate decoding. However, these parity-check matrices have too many redundant rows. To reduce decoding complexity, parity-check matrices with small number of rows are preferred. This chapter proposes a method that can build a matrix with a smaller number of rows.

**Organization of the paper**: The rest of this chapter is organized as follows. Section 2 introduces the main ideas of error-correcting codes, errors and erasures. Section 3 presents methods to construct a parity-check matrix that can correct both errors and erasures. Section 4 discusses a general solution for the covering design, which is used in the proposal. Finally, Section 5 concludes the chapter.

#### **2. Codes, errors and erasures**

#### **2.1 Linear block codes**

Let *C* be an ½ � *n; k; d* linear block code. It means that *C* is a *k*-dimensional subspace of the *n*-dimensional vector space. The set of codewords of *C* can be defined as the null space of the row space of an *r* � *n* parity-check matrix *H* ¼ *hi,j* of rank *<sup>n</sup>* � *<sup>k</sup>*. Since a vector **<sup>x</sup>** is a codeword of *<sup>C</sup>* iff **<sup>x</sup>***H<sup>T</sup>* <sup>¼</sup> 0, where the superscript *<sup>T</sup>* denotes the transpose, we can derive *r* parity-check equations PCE, as follows,

$$\text{PCE}i: \sum\_{j=1}^{n} h\_{i,j} \boldsymbol{\chi}\_{j} = \mathbf{0} \text{ for } i = 1, 2, \ldots, r. \tag{1}$$

and these codewords are the same, then this is the transmitted codeword. If they are different, then there is one, and only one, vector requiring at most *t<sup>ε</sup>* changes in nonerasure positions to become the right codeword. More information on this

Abdel-Ghaffar and Weber proposed another way of decoding over such channels [7]. First, all erasures are deleted from the received message. Errors in the resulting codeword will be corrected based on the punctured code, i.e., codewords consist of symbols in positions which are not erased. After all errors have been

The decoder can compute a parity-check matrix for the punctured code after receiving the codeword. However, this leads to time delay which is unacceptable specially in IoT applications. To reduce time delay, we can store parity-check matrices of all punctured codes corresponding to all erasure patterns. The drawback

Abdel-Ghaffar and Weber proposed using a *separating matrix* with redundant rows, providing enough parity-check equations which do not check any of the erased symbols and are sufficient to form a parity-check matrix for the punctured code obtained by deleting all erasures [7]. Having these parity-check equations not checking any of the erased symbols lead to the concept of *separation* of errors from

The basic concept of this decoding technique can be illustrated by an example as follows. We consider an (8,4,4) binary extended Hamming code with the following

A normal parity-check matrix just has only four rows as the first four rows in this separating matrix. Allowing redundant rows simplifies the decoding of erasures in addition to errors. Assume that we get a codeword **r** = 0 ∗ 011000 with one erasure in the second position. Applying the decoding technique mentioned above, firstly we delete the erasure and the resulting vector is **r**' = 0011000. This vector **r**' can be considered as a codeword of the (7,4,3) punctured code. In *H*, the first, the second and the sixth row have zeros in the second position. It means that three corresponding parity-check equations do not check the erased symbol. Based on these three rows, we can form a parity-check matrix *H*' for the punctured code, as

Using *H*', **r**' is decoded into 0011010. Putting back the erasure, we get 0\*011010. The third row of *H*, which checks the erased symbol, can be used to recover the

A normal parity-check matrix cannot be used for decoding of both errors and erasures together. Decoding is feasible when we pay the price of storing a paritycheck matrix with more rows than a normal one. In order to reduce the memory

erasure. Thus, the decoded codeword corresponding to **r** is 01011010.

of this solution is the requirement of huge memory storage at the decoder.

corrected, erasures will be recovered by the iterative decoding.

algorithm can be found in [6].

*Confidentiality and Integrity for IoT/Mobile Networks DOI: http://dx.doi.org/10.5772/intechopen.88011*

parity-check matrix, **Figure 1**.

erasures.

follows **Figure 2**.

**Figure 1.**

**29**

*A parity check matrix for the code C.*

An equation PCE*i*(**x**) is said to check **x** in position *j* iff *hi,j* 6¼ 0.

#### **2.2 Erasures**

Sometimes, at the receiver, the demodulator cannot decide which symbol the received waveform represents. In this case, we declare the received symbol as an *erasure*. When the received codeword contains erasures instead of errors, the iterative decoding can be used [8].

Here, we summarize the iterative decoding procedure using an example of the (7,4,3) binary Hamming code with the following parity-check matrix,


Since a vector **<sup>x</sup>** <sup>¼</sup> ð Þ *<sup>x</sup>*1*x*2*x*3*x*4*x*5*x*6*x*<sup>7</sup> is a codeword iff **<sup>x</sup>***H<sup>T</sup>* <sup>¼</sup> 0. Hence, every codeword has to satisfy three parity-check equations as follows.

Assume that the received vector is ∗ 010 ∗ 0, where the erased symbol is denoted by Equation A checks on *x*1, *x*3*, x*<sup>4</sup> and *x*5. If exactly one of these four symbols is erased, it can be retrieved from this equation. Thus, *x*<sup>1</sup> ¼ 1 since *x*<sup>3</sup> ¼ 0, *x*<sup>4</sup> ¼ 1, and *x*<sup>5</sup> ¼ 0. Similarly, we can derive that *x*<sup>2</sup> ¼ 1, and *x*<sup>6</sup> ¼ 0 from Equation B and C. Therefore, the iterative decoding decided that the transmitted codeword is 1101000.

Iterative decoding is successful iff erasures do not fill the positions of a *nonempty stopping set*. A stopping set is a set of positions in which there is no parity-check equation that checks exactly one symbol in these positions. The performance of iterative decoding techniques for correcting erasures depends on the sizes of the stopping sets associated with the parity-check matrix representing the code. The parity-check matrix with redundant rows could benefit the decoding performance, i.e., reducing the size of stopping sets, while increasing the decoding complexity. More information on stopping set can be found in [2, 10, 11].

#### **2.3 Separation of errors from erasures**

In this part, we discuss how to handle errors together with erasures. In this case, we can apply an algorithm using trials in which erasures are replaced by 0 or 1; and the resulting vector is decoded by a decoder which is capable of correcting errors. For binary code, two trials are sufficient [8, 12].

For example, if *C* is a binary ð Þ *n; k* -code with a Hamming distance *d* ¼ 2*t<sup>ε</sup>* þ *t*? þ 1, then *C* can correct *t<sup>ε</sup>* errors and *t*? erasures. In the presence of *no* erasures, *C* is able to correct up to *t<sup>ε</sup>* þ b c *t*?*=*2 errors. Let **r** be a received vector having at most *t<sup>ε</sup>* errors and at most *t*? erasures. Suppose the decoder constructs two vectors **r**0 and **r**1, where **r***i* is obtained by filling all erasure positions in **r** with the symbols *i, i* ¼ 0*,* 1. Since *C* is binary, in either **r**0 or **r**1, at least half of the erasure locations has the right symbols. Hence, either **r**0 or **r**1 has a distance at most *t<sup>ε</sup>* þ b c *t*?*=*2 from the transmitted codeword. Thus, any standard error correction technique can be applied. If the correction decodes both **r**0 and **r**1 to codewords,

PCE*i* :

*Recent Trends in Communication Networks*

**2.2 Erasures**

1101000.

**28**

tive decoding can be used [8].

X*n j*¼1

An equation PCE*i*(**x**) is said to check **x** in position *j* iff *hi,j* 6¼ 0.

(7,4,3) binary Hamming code with the following parity-check matrix,

codeword has to satisfy three parity-check equations as follows.

More information on stopping set can be found in [2, 10, 11].

**2.3 Separation of errors from erasures**

For binary code, two trials are sufficient [8, 12].

Sometimes, at the receiver, the demodulator cannot decide which symbol the received waveform represents. In this case, we declare the received symbol as an *erasure*. When the received codeword contains erasures instead of errors, the itera-

Here, we summarize the iterative decoding procedure using an example of the

Since a vector **<sup>x</sup>** <sup>¼</sup> ð Þ *<sup>x</sup>*1*x*2*x*3*x*4*x*5*x*6*x*<sup>7</sup> is a codeword iff **<sup>x</sup>***H<sup>T</sup>* <sup>¼</sup> 0. Hence, every

Assume that the received vector is ∗ 010 ∗ 0, where the erased symbol is denoted by Equation A checks on *x*1, *x*3*, x*<sup>4</sup> and *x*5. If exactly one of these four symbols is erased, it can be retrieved from this equation. Thus, *x*<sup>1</sup> ¼ 1 since *x*<sup>3</sup> ¼ 0, *x*<sup>4</sup> ¼ 1, and *x*<sup>5</sup> ¼ 0. Similarly, we can derive that *x*<sup>2</sup> ¼ 1, and *x*<sup>6</sup> ¼ 0 from Equation B and C. Therefore, the iterative decoding decided that the transmitted codeword is

Iterative decoding is successful iff erasures do not fill the positions of a *nonempty stopping set*. A stopping set is a set of positions in which there is no parity-check equation that checks exactly one symbol in these positions. The performance of iterative decoding techniques for correcting erasures depends on the sizes of the stopping sets associated with the parity-check matrix representing the code. The parity-check matrix with redundant rows could benefit the decoding performance, i.e., reducing the size of stopping sets, while increasing the decoding complexity.

In this part, we discuss how to handle errors together with erasures. In this case, we can apply an algorithm using trials in which erasures are replaced by 0 or 1; and the resulting vector is decoded by a decoder which is capable of correcting errors.

For example, if *C* is a binary ð Þ *n; k* -code with a Hamming distance

*d* ¼ 2*t<sup>ε</sup>* þ *t*? þ 1, then *C* can correct *t<sup>ε</sup>* errors and *t*? erasures. In the presence of *no* erasures, *C* is able to correct up to *t<sup>ε</sup>* þ b c *t*?*=*2 errors. Let **r** be a received vector having at most *t<sup>ε</sup>* errors and at most *t*? erasures. Suppose the decoder constructs two vectors **r**0 and **r**1, where **r***i* is obtained by filling all erasure positions in **r** with the symbols *i, i* ¼ 0*,* 1. Since *C* is binary, in either **r**0 or **r**1, at least half of the erasure locations has the right symbols. Hence, either **r**0 or **r**1 has a distance at most *t<sup>ε</sup>* þ b c *t*?*=*2 from the transmitted codeword. Thus, any standard error correction technique can be applied. If the correction decodes both **r**0 and **r**1 to codewords,

*hi,j xj* ¼ 0 for *i* ¼ 1*,* 2*,* …*, r:* (1)

and these codewords are the same, then this is the transmitted codeword. If they are different, then there is one, and only one, vector requiring at most *t<sup>ε</sup>* changes in nonerasure positions to become the right codeword. More information on this algorithm can be found in [6].

Abdel-Ghaffar and Weber proposed another way of decoding over such channels [7]. First, all erasures are deleted from the received message. Errors in the resulting codeword will be corrected based on the punctured code, i.e., codewords consist of symbols in positions which are not erased. After all errors have been corrected, erasures will be recovered by the iterative decoding.

The decoder can compute a parity-check matrix for the punctured code after receiving the codeword. However, this leads to time delay which is unacceptable specially in IoT applications. To reduce time delay, we can store parity-check matrices of all punctured codes corresponding to all erasure patterns. The drawback of this solution is the requirement of huge memory storage at the decoder.

Abdel-Ghaffar and Weber proposed using a *separating matrix* with redundant rows, providing enough parity-check equations which do not check any of the erased symbols and are sufficient to form a parity-check matrix for the punctured code obtained by deleting all erasures [7]. Having these parity-check equations not checking any of the erased symbols lead to the concept of *separation* of errors from erasures.

The basic concept of this decoding technique can be illustrated by an example as follows. We consider an (8,4,4) binary extended Hamming code with the following parity-check matrix, **Figure 1**.

A normal parity-check matrix just has only four rows as the first four rows in this separating matrix. Allowing redundant rows simplifies the decoding of erasures in addition to errors. Assume that we get a codeword **r** = 0 ∗ 011000 with one erasure in the second position. Applying the decoding technique mentioned above, firstly we delete the erasure and the resulting vector is **r**' = 0011000. This vector **r**' can be considered as a codeword of the (7,4,3) punctured code. In *H*, the first, the second and the sixth row have zeros in the second position. It means that three corresponding parity-check equations do not check the erased symbol. Based on these three rows, we can form a parity-check matrix *H*' for the punctured code, as follows **Figure 2**.

Using *H*', **r**' is decoded into 0011010. Putting back the erasure, we get 0\*011010. The third row of *H*, which checks the erased symbol, can be used to recover the erasure. Thus, the decoded codeword corresponding to **r** is 01011010.

A normal parity-check matrix cannot be used for decoding of both errors and erasures together. Decoding is feasible when we pay the price of storing a paritycheck matrix with more rows than a normal one. In order to reduce the memory


**Figure 1.** *A parity check matrix for the code C.*

• In case *l*≤ minf g *d; n* � *k* � 1, *H* has no stopping set of size *l* or less. For any pattern of *l* or fewer erasures, not only are there enough parity-check equations that do not check any of the erased symbols characterize the punctured code, but also there is a parity-check equation that checks exactly one of the erased symbols. It means that after all errors have been corrected, erasures can be

Let *H*' be a full rank parity-check matrix, *Si*⊆f g 1*;* 2*;* …*; n* , in which

that its last *n* � *k* � *l* rows have zeros in positions indexed by *Si* **Figure 3**.

, be distinct subsets of 1f g *;* <sup>2</sup>*;* …*; <sup>n</sup>* of size *<sup>l</sup>*, For each *<sup>i</sup>*, it is trivial

*Si* has rank *l* (*l* ≤ minf g *d; n* � *k* � 1). By elementary row operations on *H*', we

Let *HI* be a matrix which rows is the union of sets of the last *n* � *k* � *l* rows in

*<sup>i</sup>*, for each *<sup>i</sup>* <sup>¼</sup> <sup>1</sup>*,* <sup>2</sup>*,* …*, <sup>n</sup>*

. *HI* is an *<sup>l</sup>*-separating matrix of the code *<sup>C</sup>*, and it has at

*l*

, of rank *<sup>n</sup>* � *<sup>k</sup>*, such

recovered by the iterative decoding procedure.

*Confidentiality and Integrity for IoT/Mobile Networks DOI: http://dx.doi.org/10.5772/intechopen.88011*

**3.2 Separating matrix**

*l*

*<sup>i</sup>*, for *<sup>i</sup>* <sup>¼</sup> <sup>1</sup>*,* <sup>2</sup>*,* …*, <sup>n</sup>*

*n l* 

can obtain an ð Þ� *n* � *k n* matrix *H*<sup>0</sup>

*l*

ð Þ *n* � *k* � *l* rows [7] **Figure 4**.

*<sup>i</sup>* <sup>¼</sup> <sup>1</sup>*,* <sup>2</sup>*,* …*, <sup>n</sup>*

that *H*<sup>0</sup>

*H*0

most

**Figure 3.**

**Figure 4.**

**31**

*An* l*-separating matrix.*

*Independent-row separation.*

**Figure 2.**

*A parity check matrix for the punctured code.*

storage as well as the decoding complexity, a parity-check matrix with small number of rows is preferred.

Given any linear code and any given maximum number of correctable erasures, Abdel-Ghaffar and Weber introduced separating matrices yielding parity-check equations that do not check any of the erased symbols and which are sufficient to characterize all punctured codes corresponding to this maximum number of erasures [7]. This allows for the separation of erasures from errors to facilitate decoding. However, their proposal yields separating matrices which typically have *too many* redundant rows. The following part of this chapter discusses an improved method to construct such separating matrices, applying covering design, with a *smaller number of rows*.

#### **3. How to build an** *l***-separating matrix**

#### **3.1 Set separation**

Let *H* ¼ *hi,j* � � of rank *<sup>n</sup>* � *<sup>k</sup>* be an (*<sup>r</sup>* �*n*) parity-check matrix of *<sup>C</sup>*, *<sup>r</sup>*<sup>≥</sup> *<sup>n</sup>* � *<sup>k</sup>*. Let *<sup>S</sup>* be a subset of 1f g *;* <sup>2</sup>*;* …*; <sup>n</sup>* and *<sup>T</sup>* be a subset of 1f g *;* <sup>2</sup>*;* …*;<sup>r</sup>* , define *<sup>H</sup><sup>T</sup> <sup>S</sup>* ¼ *hi,j* � � with *i* ∈*T* and *j*∈*S*, be a *T* ∨ � ∨ *S*∨ submatrix of *H*. For the code *C* with the length *n*, define *C*� *<sup>S</sup>* ¼ *c*� *<sup>S</sup>* : *<sup>c</sup>*∈*C*<sup>g</sup> � be the punctured code consisting of all codewords of *<sup>C</sup>* in which the symbols in positions indexed by *S, S* ¼ f g 1*;* 2*;* …*; n* f*S* are deleted. Clearly, *C*� *<sup>S</sup>* is a linear code over *GF q*ð Þ of length *<sup>n</sup>*' <sup>¼</sup> � *S* ∨, dimension *k*'≤*k*, and Hamming distance *<sup>d</sup>*'<sup>≤</sup> *<sup>d</sup>* � � *<sup>S</sup>* <sup>∨</sup>. Let <sup>e</sup>*<sup>S</sup>* <sup>¼</sup> *<sup>i</sup>* : <sup>1</sup><sup>≤</sup> *<sup>i</sup>*<sup>≤</sup> *<sup>r</sup>; hij* <sup>¼</sup> <sup>0</sup>∀*j*∈*<sup>S</sup>* � �, define *H S*ð Þ¼ *<sup>H</sup>*<sup>~</sup> *S S*� .

**Definition 1** [7]: A parity-check matrix *H* separates *S*⊆ f g 1*;* 2*;* …*; n* iff *H S*ð Þ is a parity-check matrix of *CS*� .

**Theorem 1** [7]: A parity-check matrix *H* of an ½ � *n; k; d* linear code *C* separates a set *S* of size j j *S* ≤*d* � 1 iff *H S*ð Þ has rank *n* � *k* � j j *S* .

**Definition 2** [7]: If *H* separates all sets *S* of size *l* for a fixed *l* ≤ minf g *d; n* � *k* � 1, it is *l*-separating.

If *H* is an *l*-separating parity-check matrix of the code *C*, based on *H*, we can construct a parity-check matrix for any code punctured up to a fixed number *l* of symbols. *H* has two features:

• *H* can separate erasures from errors, since *H* has enough parity-check equations that do not check any erased symbols, and are sufficient to characterize the punctured code. It means that the punctured code, which is formed by deleting erased symbols, can be corrected errors by a sub-matrix of *H*.

*Confidentiality and Integrity for IoT/Mobile Networks DOI: http://dx.doi.org/10.5772/intechopen.88011*

• In case *l*≤ minf g *d; n* � *k* � 1, *H* has no stopping set of size *l* or less. For any pattern of *l* or fewer erasures, not only are there enough parity-check equations that do not check any of the erased symbols characterize the punctured code, but also there is a parity-check equation that checks exactly one of the erased symbols. It means that after all errors have been corrected, erasures can be recovered by the iterative decoding procedure.

#### **3.2 Separating matrix**

storage as well as the decoding complexity, a parity-check matrix with small num-

decoding. However, their proposal yields separating matrices which typically have *too many* redundant rows. The following part of this chapter discusses an improved method to construct such separating matrices, applying covering design, with a

*<sup>S</sup>* be a subset of 1f g *;* <sup>2</sup>*;* …*; <sup>n</sup>* and *<sup>T</sup>* be a subset of 1f g *;* <sup>2</sup>*;* …*;<sup>r</sup>* , define *<sup>H</sup><sup>T</sup>*

*<sup>S</sup>* is a linear code over *GF q*ð Þ of length *<sup>n</sup>*' <sup>¼</sup> �

**Definition 2** [7]: If *H* separates all sets *S* of size *l* for a fixed

erased symbols, can be corrected errors by a sub-matrix of *H*.

set *S* of size j j *S* ≤*d* � 1 iff *H S*ð Þ has rank *n* � *k* � j j *S* .

*l* ≤ minf g *d; n* � *k* � 1, it is *l*-separating.

*i* ∈*T* and *j*∈*S*, be a *T* ∨ � ∨ *S*∨ submatrix of *H*. For the code *C* with the length *n*,

**Definition 1** [7]: A parity-check matrix *H* separates *S*⊆ f g 1*;* 2*;* …*; n* iff *H S*ð Þ is a

**Theorem 1** [7]: A parity-check matrix *H* of an ½ � *n; k; d* linear code *C* separates a

If *H* is an *l*-separating parity-check matrix of the code *C*, based on *H*, we can construct a parity-check matrix for any code punctured up to a fixed number *l* of

• *H* can separate erasures from errors, since *H* has enough parity-check equations that do not check any erased symbols, and are sufficient to characterize the punctured code. It means that the punctured code, which is formed by deleting

in which the symbols in positions indexed by *S, S* ¼ f g 1*;* 2*;* …*; n* f*S* are deleted.

� � of rank *<sup>n</sup>* � *<sup>k</sup>* be an (*<sup>r</sup>* �*n*) parity-check matrix of *<sup>C</sup>*, *<sup>r</sup>*<sup>≥</sup> *<sup>n</sup>* � *<sup>k</sup>*. Let

*<sup>S</sup>* : *<sup>c</sup>*∈*C*<sup>g</sup> � be the punctured code consisting of all codewords of *<sup>C</sup>*

*<sup>S</sup>* <sup>∨</sup>. Let <sup>e</sup>*<sup>S</sup>* <sup>¼</sup> *<sup>i</sup>* : <sup>1</sup><sup>≤</sup> *<sup>i</sup>*<sup>≤</sup> *<sup>r</sup>; hij* <sup>¼</sup> <sup>0</sup>∀*j*∈*<sup>S</sup>* � �, define

*<sup>S</sup>* ¼ *hi,j*

*S* ∨, dimension *k*'≤*k*, and

� � with

Given any linear code and any given maximum number of correctable erasures, Abdel-Ghaffar and Weber introduced separating matrices yielding parity-check equations that do not check any of the erased symbols and which are sufficient to characterize all punctured codes corresponding to this maximum number of erasures [7]. This allows for the separation of erasures from errors to facilitate

ber of rows is preferred.

*A parity check matrix for the punctured code.*

*Recent Trends in Communication Networks*

**Figure 2.**

*smaller number of rows*.

**3.1 Set separation**

Let *H* ¼ *hi,j*

*<sup>S</sup>* ¼ *c*�

*S S*� .

Hamming distance *<sup>d</sup>*'<sup>≤</sup> *<sup>d</sup>* � �

parity-check matrix of *CS*� .

symbols. *H* has two features:

define *C*�

Clearly, *C*�

*H S*ð Þ¼ *<sup>H</sup>*<sup>~</sup>

**30**

**3. How to build an** *l***-separating matrix**

Let *H*' be a full rank parity-check matrix, *Si*⊆f g 1*;* 2*;* …*; n* , in which *<sup>i</sup>* <sup>¼</sup> <sup>1</sup>*,* <sup>2</sup>*,* …*, <sup>n</sup> l* , be distinct subsets of 1f g *;* <sup>2</sup>*;* …*; <sup>n</sup>* of size *<sup>l</sup>*, For each *<sup>i</sup>*, it is trivial that *H*<sup>0</sup> *Si* has rank *l* (*l* ≤ minf g *d; n* � *k* � 1). By elementary row operations on *H*', we can obtain an ð Þ� *n* � *k n* matrix *H*<sup>0</sup> *<sup>i</sup>*, for each *<sup>i</sup>* <sup>¼</sup> <sup>1</sup>*,* <sup>2</sup>*,* …*, <sup>n</sup> l* , of rank *<sup>n</sup>* � *<sup>k</sup>*, such that its last *n* � *k* � *l* rows have zeros in positions indexed by *Si* **Figure 3**.

Let *HI* be a matrix which rows is the union of sets of the last *n* � *k* � *l* rows in *H*0 *<sup>i</sup>*, for *<sup>i</sup>* <sup>¼</sup> <sup>1</sup>*,* <sup>2</sup>*,* …*, <sup>n</sup> l* . *HI* is an *<sup>l</sup>*-separating matrix of the code *<sup>C</sup>*, and it has at most *n l* ð Þ *n* � *k* � *l* rows [7] **Figure 4**.

**Figure 3.** *Independent-row separation.*

**Figure 4.** *An* l*-separating matrix.*

#### **3.3 A more efficient separating matrix**

In this section, we propose a method that can construct an *l*-separating matrix with a smaller number of rows. This method implements the idea of *covering design* [13, 14]. Basically, given 1≤*t*≤ *u*≤*v*, a ð Þ *v; u; t* covering design is a collection of *u*-element subsets of *V* ¼ f g 1*;* 2*;* …*; v* , called blocks, such that each *t*-element subset of *V* is contained in at least one block, e.g., 1f g *;* 2 is contained in 1f g *;* 2*;* 3 .

For our specific situation, consider an ð Þ *n; b; l* covering design. Let *B* ¼ f g *Bi* be a set of *b*-element subsets, 1≤ *l*≤*b*≤ minf g *d; n* � *k* � 1, such that every *l*-element subset *Si* is contained in at least one member of *B*. Assign to each *Si*,

*<sup>i</sup>* <sup>¼</sup> <sup>1</sup>*,* <sup>2</sup>*,* …*, <sup>n</sup> l* , an element *Bj* of *<sup>B</sup>* such that *Si* is contained in *Bj*. *<sup>H</sup>*<sup>0</sup> *Bj* has rank *b*. For any *Bj*, by elementary row operations on *H*', we can obtain an ð Þ� *n* � *k n*matrix of rank *n* � *k* such that its last *n* � *k* � *b* rows have zeros in positions indexed by *Bj*. After arranging columns, we obtain a matrix *H*<sup>1</sup> *<sup>j</sup>* with the following format (Step 1) **Figure 5**.

Consider the set *Si* assigned to *Bj*, by further elementary row operations, *H*<sup>1</sup>

Following this method, if *Si* and *Si*<sup>0</sup> belong to the same *Bj*, the last *n* � *k* � *b* rows

number of rows in Approach 2 is strictly smaller than in Approach 1. In case *b* ¼ *l*, two approaches are the same. For a given *l*, we can choose an appropriate *b* to

need at most 21 subsets of 3-elements, i.e., {{1,2,3}, {1,2,4}, {1,2,5}, {1,2,6}, {1,2,7}, {1,2,8}, {1,3,4}, {1,3,5}, {1,3,6}, {1,3,7}, {1,3,8}, {1,4,5}, {1,4,6}, {1,4,7}, {1,4,8}, {1,5,6}, {1,5,7}, {1,5,8}, {1,6,7}, {1,6,8}, {1,7,8}}, to form all 28 subsets of 2 elements. For example, based on the subset {1,2,3}, we can form {1,2}, {2,3}, {1,3}. Using 21 subsets of size 3 mentioned above, we can construct all 28 subsets

The covering design problem has been investigated since many years ago. However, until now, there is no general *optimal* solution for all triples ð Þ *v; u; t* . In this section, we propose a *covering design* valid for all triples ð Þ *v; u; t* . This design is

*<sup>i</sup>*<sup>0</sup> are the same. It follows that the matrix which rows is the union of the

, is an *<sup>l</sup>*-separating parity-check matrix of *<sup>C</sup>*. Let *B n*ð Þ *; <sup>b</sup>; <sup>l</sup>* denote

*<sup>j</sup>*, *j* ¼ 1*,* 2*,* …*,* ∨*B*∨, and the rows *l* þ 1*, l* þ 2*,* …*, b* of *H*<sup>0</sup>

ð Þ *b* � *l* rows. It is obvious to see that the upper bound on

8 2

= 56 subsets of 3-elements of *<sup>V</sup>* <sup>¼</sup> <sup>f</sup>1,2,…,8g. However, we only

= 28 subsets of 2-

be changed into a matrix such that rows *l* þ 1*, l* þ 2*,* …*, b* have zeros in positions indexed by *Si*, and rows *b* þ 1*, b* þ 2*,* …*, n* � *k* have zeros in positions indexed by *Bj*. After column arrangement, we obtain a matrix with the following format (Step 2),

the *minimum* size of *B*, i.e., *B n*ð Þ¼ *; b; l* min |*B*|. This matrix has at most

Consider a ð Þ *v; u; t* covering design, where 1≤ *t*≤*u*≤ *v*.

not optimal but it can give a general solution for the problem.

**Example 1**: Given that *v* ¼ 8*, u* ¼ 3*, t* ¼ 2. There are

*n l* 

*Confidentiality and Integrity for IoT/Mobile Networks DOI: http://dx.doi.org/10.5772/intechopen.88011*

**Figure 6**.

**Figure 7.**

*<sup>i</sup>* and *H*<sup>0</sup>

*<sup>i</sup>* <sup>¼</sup> <sup>1</sup>*,* <sup>2</sup>*,* …*, <sup>n</sup>*

last *n* � *k* � *l* rows in *H*<sup>0</sup>

ð Þ *n* � *k* � *b B n*ð Þþ *; b; l*

**4. Covering design**

elements, and

of size 2.

**33**

*l*

*A more efficient* l*-separating matrix.*

achieve the best result **Figure 7**.

8 3

in *H*<sup>0</sup>

*<sup>j</sup>* can

*i*,

**Figure 5.** *Row separation—Step 1.*

**Figure 6.** *Row separation—Step 2.*

*Confidentiality and Integrity for IoT/Mobile Networks DOI: http://dx.doi.org/10.5772/intechopen.88011*

#### **Figure 7.**

**3.3 A more efficient separating matrix**

*Recent Trends in Communication Networks*

*<sup>i</sup>* <sup>¼</sup> <sup>1</sup>*,* <sup>2</sup>*,* …*, <sup>n</sup>*

(Step 1) **Figure 5**.

**Figure 5.**

**Figure 6.**

**32**

*Row separation—Step 2.*

*Row separation—Step 1.*

*l* 

In this section, we propose a method that can construct an *l*-separating matrix with a smaller number of rows. This method implements the idea of *covering design* [13, 14]. Basically, given 1≤*t*≤ *u*≤*v*, a ð Þ *v; u; t* covering design is a collection of *u*-element subsets of *V* ¼ f g 1*;* 2*;* …*; v* , called blocks, such that each *t*-element subset

For our specific situation, consider an ð Þ *n; b; l* covering design. Let *B* ¼ f g *Bi* be a set of *b*-element subsets, 1≤ *l*≤*b*≤ minf g *d; n* � *k* � 1, such that every *l*-element

, an element *Bj* of *B* such that *Si* is contained in *Bj*. *H*<sup>0</sup>

For any *Bj*, by elementary row operations on *H*', we can obtain an ð Þ� *n* � *k n*matrix of rank *n* � *k* such that its last *n* � *k* � *b* rows have zeros in positions indexed

*Bj* has rank *b*.

*<sup>j</sup>* with the following format

of *V* is contained in at least one block, e.g., 1f g *;* 2 is contained in 1f g *;* 2*;* 3 .

subset *Si* is contained in at least one member of *B*. Assign to each *Si*,

by *Bj*. After arranging columns, we obtain a matrix *H*<sup>1</sup>

*A more efficient* l*-separating matrix.*

Consider the set *Si* assigned to *Bj*, by further elementary row operations, *H*<sup>1</sup> *<sup>j</sup>* can be changed into a matrix such that rows *l* þ 1*, l* þ 2*,* …*, b* have zeros in positions indexed by *Si*, and rows *b* þ 1*, b* þ 2*,* …*, n* � *k* have zeros in positions indexed by *Bj*. After column arrangement, we obtain a matrix with the following format (Step 2), **Figure 6**.

Following this method, if *Si* and *Si*<sup>0</sup> belong to the same *Bj*, the last *n* � *k* � *b* rows in *H*<sup>0</sup> *<sup>i</sup>* and *H*<sup>0</sup> *<sup>i</sup>*<sup>0</sup> are the same. It follows that the matrix which rows is the union of the last *n* � *k* � *l* rows in *H*<sup>0</sup> *<sup>j</sup>*, *j* ¼ 1*,* 2*,* …*,* ∨*B*∨, and the rows *l* þ 1*, l* þ 2*,* …*, b* of *H*<sup>0</sup> *i*, *<sup>i</sup>* <sup>¼</sup> <sup>1</sup>*,* <sup>2</sup>*,* …*, <sup>n</sup> l* , is an *<sup>l</sup>*-separating parity-check matrix of *<sup>C</sup>*. Let *B n*ð Þ *; <sup>b</sup>; <sup>l</sup>* denote the *minimum* size of *B*, i.e., *B n*ð Þ¼ *; b; l* min |*B*|. This matrix has at most ð Þ *n* � *k* � *b B n*ð Þþ *; b; l n l* ð Þ *b* � *l* rows. It is obvious to see that the upper bound on number of rows in Approach 2 is strictly smaller than in Approach 1. In case *b* ¼ *l*, two approaches are the same. For a given *l*, we can choose an appropriate *b* to achieve the best result **Figure 7**.

#### **4. Covering design**

Consider a ð Þ *v; u; t* covering design, where 1≤ *t*≤*u*≤ *v*.

**Example 1**: Given that *v* ¼ 8*, u* ¼ 3*, t* ¼ 2. There are 8 2 = 28 subsets of 2-

elements, and 8 3 = 56 subsets of 3-elements of *<sup>V</sup>* <sup>¼</sup> <sup>f</sup>1,2,…,8g. However, we only need at most 21 subsets of 3-elements, i.e., {{1,2,3}, {1,2,4}, {1,2,5}, {1,2,6}, {1,2,7}, {1,2,8}, {1,3,4}, {1,3,5}, {1,3,6}, {1,3,7}, {1,3,8}, {1,4,5}, {1,4,6}, {1,4,7}, {1,4,8}, {1,5,6}, {1,5,7}, {1,5,8}, {1,6,7}, {1,6,8}, {1,7,8}}, to form all 28 subsets of 2 elements. For example, based on the subset {1,2,3}, we can form {1,2}, {2,3}, {1,3}. Using 21 subsets of size 3 mentioned above, we can construct all 28 subsets of size 2.

The covering design problem has been investigated since many years ago. However, until now, there is no general *optimal* solution for all triples ð Þ *v; u; t* . In this section, we propose a *covering design* valid for all triples ð Þ *v; u; t* . This design is not optimal but it can give a general solution for the problem.

#### **4.1 Approach 1**

Firstly, we show that with at most *v* � ð Þ *u* � *t t* subsets of size *<sup>u</sup>*, we can form all *v t* subsets of size *<sup>t</sup>*.


#### **4.2 Approach 2**

By modifying *Approach 1*, we show that some *u*-element subsets can be *merged* to reduce *B*∨.

	- Elements in each subset are arranged in ascending order, e.g., {1,2,3}.
	- Subsets are arranged into columns. Subsets are in one column iff their first *t* � 1 elements are the same (except the *special column* mentioned below). Hence, subsets in one column are different from each other only in the last element. The subset with the smaller last element will be listed above.

We can merge the last two subsets in each column (except the special column) because: (a) the first *u* � 1 elements in the last two subsets are also in another subset in the columns. Thus, any subset of size *t* formed by using these *u* � 1 elements can be form by any other subset in the column; (b) any subset of size *t* containing

**Example 2**: Given that *v* ¼ 9*, u* ¼ 5*, t* ¼ 4. Following the first three steps of

First, take {1} out of the set. Following Step 2, form all subsets of size 4, and arrange them into columns. Put {1} back into each subset of size 4 to have subsets of size 5. We denote subsets in boxes are subsets which can be merged **Figure 8**.

the box are {1*,* 2*,* 3*,* 4*,* 8} and {1*,* 2*,* 3*,* 4*,* 9}. First, take the union of the two, i.e., {1*,* 2*,* 3*,* 4*,* 8*,* 9}, and then eliminate the first element; thus, this results in {2*,* 3*,* 4*,* 8*,* 9}. Therefore, Step 4 of Approach 2 gives the following result. It is easy to see that

The merged step (Step 4): For example, consider the first column, two subsets in

f g 1*; v* � 1 or 1f g *; v* can be formed by subsets in the *special column*.

any subset of size 4 can be formed by subsets in **Figure 9**.

Approach 2, we get:

*The first three steps of Approach 2.*

*Confidentiality and Integrity for IoT/Mobile Networks DOI: http://dx.doi.org/10.5772/intechopen.88011*

**Figure 8.**

**35**

	- Take the union of two subsets, i.e., the size of the union subset is *u* þ 1.
	- Eliminate the first element of the union subset, i.e., its size is now *u*.

*Confidentiality and Integrity for IoT/Mobile Networks DOI: http://dx.doi.org/10.5772/intechopen.88011*

**4.1 Approach 1**

With these

*v t* 

**4.2 Approach 2**

reduce *B*∨.

rules:

that there are

*merged set*, by this rule

**34**

*v t* 

all

Firstly, we show that with at most

*Recent Trends in Communication Networks*

*v* � ð Þ *u* � *t t* 

subsets of size*t:*

subsets of size *t*.

*v* � ð Þ *u* � *t t* 

1. Take the first *u* � *t* elements, i.e., 1f g *;* 2*; ::u* � *t* , out of *V* ¼ f g 1*;* 2*;* …*; v* .

form all subsets of size *<sup>t</sup>*. The number of subsets is *<sup>v</sup>* � ð Þ *<sup>u</sup>* � *<sup>t</sup>*

2. The rest of the set is f g *u* � *t* þ 1*; u* � *t* þ 2*;* …*; v* � 1*; v* . Based on these elements,

3. Put the first *u* � *t* elements into each subset of size *t* to have subsets of size *u*.

By modifying *Approach 1*, we show that some *u*-element subsets can be *merged* to

2. The rest of the set is f g *u* � *t* þ 1*; u* � *t* þ 2*;* …*; v* � 1*; v* . Based on these elements, form all subsets of size *t* and arrange them into columns based on the following

• Elements in each subset are arranged in ascending order, e.g., {1,2,3}.

• *Special column*: In case *t*≥2, we arrange all subsets containing both

3. Put the first *u* � *t* elements into each subset of size *t* to have subsets of size *u*.

4.If the number of subsets in the *longest column* is greater or equal to three and the *special column* exists, we can merge the last two subsets, which contain either *v* � 1 or *v*, in each column (except the *special column*) into one, i.e., the

• Take the union of two subsets, i.e., the size of the union subset is *u* þ 1.

• Eliminate the first element of the union subset, i.e., its size is now *u*.

*v* � ð Þ� *u* � *t* 2 *t* � 2 

• Subsets are arranged into columns. Subsets are in one column iff their first *t* � 1 elements are the same (except the *special column* mentioned below). Hence, subsets in one column are different from each other only in the last element. The subset with the smaller last element will be listed above.

element *v* � 1*, v* in a column and name it special column. It is easy to see

subsets in this column.

1. Take the first *u* � *t* elements, i.e., 1f g *;* 2*; ::u* � *t* , out of *V* ¼ f g 1*;* 2*;* …*; v* .

subsets of size *u*, we can form

.

*t* 

subsets of size *u*, it is easy to see that we can form all

**Figure 8.** *The first three steps of Approach 2.*

We can merge the last two subsets in each column (except the special column) because: (a) the first *u* � 1 elements in the last two subsets are also in another subset in the columns. Thus, any subset of size *t* formed by using these *u* � 1 elements can be form by any other subset in the column; (b) any subset of size *t* containing f g 1*; v* � 1 or 1f g *; v* can be formed by subsets in the *special column*.

**Example 2**: Given that *v* ¼ 9*, u* ¼ 5*, t* ¼ 4. Following the first three steps of Approach 2, we get:

First, take {1} out of the set. Following Step 2, form all subsets of size 4, and arrange them into columns. Put {1} back into each subset of size 4 to have subsets of size 5. We denote subsets in boxes are subsets which can be merged **Figure 8**.

The merged step (Step 4): For example, consider the first column, two subsets in the box are {1*,* 2*,* 3*,* 4*,* 8} and {1*,* 2*,* 3*,* 4*,* 9}. First, take the union of the two, i.e.,

{1*,* 2*,* 3*,* 4*,* 8*,* 9}, and then eliminate the first element; thus, this results in {2*,* 3*,* 4*,* 8*,* 9}. Therefore, Step 4 of Approach 2 gives the following result. It is easy to see that any subset of size 4 can be formed by subsets in **Figure 9**.

way to build a separating parity-check matrix with a smaller set of rows. This method reduces both decoding complexity and memory storage. Besides, we also present a covering design. This design is not optimal but it gives a general solution

Faculty of Electronic and Telecommunication Engineering, The University of

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Danang—University of Science and Technology, Vietnam

\*Address all correspondence to: tringominh@gmail.com

provided the original work is properly cited.

and Technology through the grant T2019-02-13 and T2019-02-14.

*Confidentiality and Integrity for IoT/Mobile Networks DOI: http://dx.doi.org/10.5772/intechopen.88011*

The authors are supported by The University of Danang—University of Science

for all triple ð Þ *v; u; t* .

**Acknowledgements**

**Author details**

Tri Ngo Minh

**37**

**Figure 9.** *The last step of Approach 2.*

The number of reduced subsets is equal to the number of subsets that contain the elements *<sup>v</sup>* � 1 or *<sup>v</sup>*. Thus, the number of reduced subsets is *<sup>v</sup>* � ð Þ� *<sup>u</sup>* � *<sup>t</sup>* <sup>2</sup> *t* � 1 . Therefore, with at most *<sup>v</sup>* � ð Þ *<sup>u</sup>* � *<sup>t</sup> t* � *<sup>v</sup>* � ð Þ� *<sup>u</sup>* � *<sup>t</sup>* <sup>2</sup> *t* � 1 subsets of size *<sup>u</sup>*, we can form all *<sup>v</sup> t* subsets of size *<sup>t</sup>*.

#### **5. Conclusions**

This chapter discusses how to ensure confidentiality and integrity for data in IoT systems. The chapter focuses more on integrity which can be ensured via the implementation of error-correcting codes. Separating parity-check matrices are useful for decoding over channels causing both errors and erasures. We propose a

*Confidentiality and Integrity for IoT/Mobile Networks DOI: http://dx.doi.org/10.5772/intechopen.88011*

way to build a separating parity-check matrix with a smaller set of rows. This method reduces both decoding complexity and memory storage. Besides, we also present a covering design. This design is not optimal but it gives a general solution for all triple ð Þ *v; u; t* .

#### **Acknowledgements**

The authors are supported by The University of Danang—University of Science and Technology through the grant T2019-02-13 and T2019-02-14.

### **Author details**

The number of reduced subsets is equal to the number of subsets that contain the elements *<sup>v</sup>* � 1 or *<sup>v</sup>*. Thus, the number of reduced subsets is *<sup>v</sup>* � ð Þ� *<sup>u</sup>* � *<sup>t</sup>* <sup>2</sup>

This chapter discusses how to ensure confidentiality and integrity for data in IoT

systems. The chapter focuses more on integrity which can be ensured via the implementation of error-correcting codes. Separating parity-check matrices are useful for decoding over channels causing both errors and erasures. We propose a

� *<sup>v</sup>* � ð Þ� *<sup>u</sup>* � *<sup>t</sup>* <sup>2</sup> *t* � 1 

*t* 

subsets of size *t*.

Therefore, with at most *<sup>v</sup>* � ð Þ *<sup>u</sup>* � *<sup>t</sup>*

*Recent Trends in Communication Networks*

*t* 

can form all *<sup>v</sup>*

**Figure 9.**

*The last step of Approach 2.*

**5. Conclusions**

**36**

*t* � 1 

subsets of size *u*, we

.

Tri Ngo Minh Faculty of Electronic and Telecommunication Engineering, The University of Danang—University of Science and Technology, Vietnam

\*Address all correspondence to: tringominh@gmail.com

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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[5] Mac Williams FJ, Sloane NJA. The Theory of Error-Correcting Codes. North-Holland Publishing Company; 1977

[6] Vanstone SA, van Oorschot PC. An Introduction to Error-Correcting Codes with Applications. Norwell, MA: Kluwer; 1989

[7] Abdel-Ghaffar KAS, Weber JH. Separating erasures from errors for decoding. In: Proceedings of the IEEE International Symposium on Information Theory; Toronto, Canada; 2008. pp. 215-219

[8] Weber JH. Lecture Notes: Error-Correcting Codes. Delft University of Technology; 2007

[9] Di C, Proietti D, Telatar IE, Richardson TJ, Urbanke RL. Finitelength analysis of low-density paritycheck codes on the binary erasure channel. IEEE Transactions on Information Theory. 2002;**48**(6): 1570-1579

[10] Schwartz M, Vardy A. On the stopping distance and the stopping redundancy of codes. IEEE Transactions on Information Theory. 2006;**52**(3): 922-932

[11] Weber JH, Abdel-Ghaffar KAS. Results on parity-check matrices with optimal stopping and/or dead-end set enumerators. IEEE Transactions on Information Theory. 2008;**54**(3): 1368-1374

[12] Hollmann HDL, Tolhuizen LMGM. On parity check collections for iterative erasure decoding that correct all correctable erasure patterns of a given size. IEEE Transactions on Information Theory. 2007;**53**(2):823-828

[13] Dinitz JH, Stinson DR. Contemporary Design Theory: A Collection of Surveys. A Wiley-Inter-Science Publication; 1992

[14] La Jolla Covering Repository. Available from: http://www.ccrwest. org/cover.html

**39**

**Chapter 4**

**Abstract**

**1. Introduction**

*Ireneusz Kubiak*

Electromagnetic Eavesdropping

expensive solutions based on shielding, zoning and filtering.

**Keywords:** electromagnetic eavesdropping, leakage information, protection of information, valuable (sensitive) emission, electromagnetic infiltration process,

Protection of information against electromagnetic eavesdropping in modern electronic systems is a big challenge. Such kind of eavesdropping is connected with electromagnetic emissions which are correlated with processed information [1–3]. This problem increases with a higher and higher use of electronic devices for processing and transmitting information. It results from the fact that each electronic device is the source of electromagnetic disturbances in particular unintentional emission of electromagnetic energy transited in surrounding space. Very often signals of unintentional emission could be correlated with processed information. The electromagnetic emissions with distinctive features can arise at any stage of processing of information (e.g. transmission, displaying on screen, printing) which occur in the electric form [1, 4–8]. Video signals are particularly dangerous (**Figure 1**) [9, 10]. Video graphics array (VGA) and digital video interface (DVI) [11, 12] are video standards currently used among other things in nonpublic information systems (other elements—keyboard, screen and main unit—of computer station could be also sources of sensitive emissions [13, 14]). But the graphic lines (VGA, DVI and laser printers) are most susceptible to electromagnetic eavesdropping. These

image and signal processing, data acquisition, identification, recognition

Protection of information against electromagnetic penetration is a huge challenge. Especially this issue applies to computer station that processes protected information and that is a source of electromagnetic disturbances. These disturbances could be correlated with processed graphic information. Therefore, very often, they are called valuable or unintentional emissions. To protect the information, different methods of engineering of electromagnetic compatibility are used, e.g. electromagnetic gaskets, signal and power filters and electromagnetic shielding. The use of these methods causes a special device to become very heavy, and the looks of such device aren't nice. A new universal solution based on safe fonts is proposed. Safe fonts protect processed information against electromagnetic penetration in each case of graphic source of valuable emissions. These fonts protect not only Video Graphics Array (VGA) but also Digital Video Interface (DVI) standards. These fonts are also useful from electromagnetic protection's point of view in the case of the use of laser printers. All analyses are based on images reconstructed from valuable emissions. These emissions are measured in a range of frequencies from 100 MHz to 1.5 GHz. Safe fonts are simple solution that counteract electromagnetic eavesdropping process. They can replace

### **Chapter 4** Electromagnetic Eavesdropping

*Ireneusz Kubiak*

### **Abstract**

**References**

1982. pp. 11-20

**226**(10):2375-2392

University Press; 2006

International; 2004

1977

Kluwer; 1989

2008. pp. 215-219

Technology; 2007

1570-1579

**38**

Coding. Pearson Education

[1] Goguen JA, Meseguer J. Security policies and security models. In: IEEE Symposium on Security and Privacy;

*Recent Trends in Communication Networks*

redundancy of codes. IEEE Transactions on Information Theory. 2006;**52**(3):

[11] Weber JH, Abdel-Ghaffar KAS. Results on parity-check matrices with optimal stopping and/or dead-end set enumerators. IEEE Transactions on Information Theory. 2008;**54**(3):

[12] Hollmann HDL, Tolhuizen LMGM. On parity check collections for iterative

erasure decoding that correct all correctable erasure patterns of a given size. IEEE Transactions on Information

Theory. 2007;**53**(2):823-828

[13] Dinitz JH, Stinson DR. Contemporary Design Theory: A Collection of Surveys. A Wiley-Inter-

Science Publication; 1992

org/cover.html

[14] La Jolla Covering Repository. Available from: http://www.ccrwest.

922-932

1368-1374

[2] Ngo TM, Huisman M. Complexity and information flow analysis for multithreaded programs. The European Physical Journal Special Topics. 2017;

[3] Roth RM. Introduction to Coding Theory. Cambridge, UK: Cambridge

[4] Lin S, Costello DJ Jr. Error Control

[5] Mac Williams FJ, Sloane NJA. The Theory of Error-Correcting Codes. North-Holland Publishing Company;

[6] Vanstone SA, van Oorschot PC. An Introduction to Error-Correcting Codes with Applications. Norwell, MA:

[7] Abdel-Ghaffar KAS, Weber JH. Separating erasures from errors for decoding. In: Proceedings of the IEEE

Information Theory; Toronto, Canada;

[8] Weber JH. Lecture Notes: Error-Correcting Codes. Delft University of

[9] Di C, Proietti D, Telatar IE, Richardson TJ, Urbanke RL. Finitelength analysis of low-density paritycheck codes on the binary erasure channel. IEEE Transactions on Information Theory. 2002;**48**(6):

[10] Schwartz M, Vardy A. On the stopping distance and the stopping

International Symposium on

Protection of information against electromagnetic penetration is a huge challenge. Especially this issue applies to computer station that processes protected information and that is a source of electromagnetic disturbances. These disturbances could be correlated with processed graphic information. Therefore, very often, they are called valuable or unintentional emissions. To protect the information, different methods of engineering of electromagnetic compatibility are used, e.g. electromagnetic gaskets, signal and power filters and electromagnetic shielding. The use of these methods causes a special device to become very heavy, and the looks of such device aren't nice. A new universal solution based on safe fonts is proposed. Safe fonts protect processed information against electromagnetic penetration in each case of graphic source of valuable emissions. These fonts protect not only Video Graphics Array (VGA) but also Digital Video Interface (DVI) standards. These fonts are also useful from electromagnetic protection's point of view in the case of the use of laser printers. All analyses are based on images reconstructed from valuable emissions. These emissions are measured in a range of frequencies from 100 MHz to 1.5 GHz. Safe fonts are simple solution that counteract electromagnetic eavesdropping process. They can replace expensive solutions based on shielding, zoning and filtering.

**Keywords:** electromagnetic eavesdropping, leakage information, protection of information, valuable (sensitive) emission, electromagnetic infiltration process, image and signal processing, data acquisition, identification, recognition

#### **1. Introduction**

Protection of information against electromagnetic eavesdropping in modern electronic systems is a big challenge. Such kind of eavesdropping is connected with electromagnetic emissions which are correlated with processed information [1–3]. This problem increases with a higher and higher use of electronic devices for processing and transmitting information. It results from the fact that each electronic device is the source of electromagnetic disturbances in particular unintentional emission of electromagnetic energy transited in surrounding space. Very often signals of unintentional emission could be correlated with processed information. The electromagnetic emissions with distinctive features can arise at any stage of processing of information (e.g. transmission, displaying on screen, printing) which occur in the electric form [1, 4–8]. Video signals are particularly dangerous (**Figure 1**) [9, 10].

Video graphics array (VGA) and digital video interface (DVI) [11, 12] are video standards currently used among other things in nonpublic information systems (other elements—keyboard, screen and main unit—of computer station could be also sources of sensitive emissions [13, 14]). But the graphic lines (VGA, DVI and laser printers) are most susceptible to electromagnetic eavesdropping. These

#### **Figure 1.**

*Examples of reconstructed images for sources of sensitive emissions in the form of (a) VGA standard (receiving frequency fo = 681 MHz, measure bandwidth BW = 10 MHz) and (b) DVI standard (receiving frequency fo = 852 MHz, measure bandwidth BW = 50 MHz).*

standards are the object of the research on solutions that effectively protect processed graphical data. Most frequently, the only solutions used for electromagnetic data protection are those design-related which decrease the level of unwanted emissions at a source. Many people consider which standard is safer.

Another no less dangerous source of electromagnetic emission, formidable from the point of view of the possibility of conducting electromagnetic "watch", are computer laser printers [15, 16]. They translate the electronic form of processed data into graphical form during the printing process. As with every electronic device, printers are sources of electromagnetic emanations [17]. Besides control signals, which carry no information (e.g. directing the operation of stepper motors or heaters), there are other signals (useful signals) that are correlated with the information being processed. Such emissions are called "sensitive" or "valuable" or "compromising" emanations from the point of view of electromagnetic protection of processed information. Processed data may be information displayed on a computer screen or printed (**Figure 2**).

Organizational and technical solutions are the most often used methods for limiting infiltration sensitivity of devices. Technical solutions are limited to changes in

**41**

*Electromagnetic Eavesdropping*

by users of these devices.

**Figure 2.**

of font characters.

nition (OCR).

the signal *y*(*t*) exists:

printed information was described in [18].

*DOI: http://dx.doi.org/10.5772/intechopen.86478*

*Sources of sensitive emissions on an example of a personal computer (PC).*

the design of devices that typically increase the cost of such devices and sometimes limit their functionality. Therefore, it is desirable to find solutions that avoid these drawbacks and at the same time allow "safe" processing of classified information. An example of an organizational solution might be the establishment of a "control zone" around susceptible devices, relying on distance to attenuate signals below levels that can be received outside the control zone. Both solutions aren't acceptable

Note that the costs of acquiring a single computer set, referred to as TEMPEST class, are an expense of several of thousand dollars. That is why "software solutions", based on the use of "safe fonts", are mentioned more and more often. As shown by the results of conducted studies, classified information processed with the use of them becomes safe for sources in both the form of video track standard VGA and DVI and video track of laser printers. In the case of laser printers, one technical method that is commonly used in the field of electromagnetic compatibility—both to reduce the amount of electromagnetic interference emitted

Currently there are new searched methods based on software solutions. Such solutions could change the character of radiation source. The methods could be used to support other solutions or they could be used alone. One of them is safe fonts [19, 20]. Very often such fonts are called TEMPEST fonts. There are three proposed sets of such fonts: Symmetrical Safe font, Asymmetrical Safe font and Simply Safe font (**Figure 3**). These sets of fonts differ in properties of construction

Usefulness of these fonts was confirmed from electromagnetic protection's point of view for analogue graphic standard VGA, digital graphic standard DVI and laser printers. The collections of these fonts also are resistant to optical character recog-

A side-channel attack (SCA) plays a very important role in the electromagnetic eavesdropping process. The SCA is built from a source of emission, a receiver of

This type of SCA has the characteristics of a high-pass filter, which is an important property from the protection of information against electromagnetic infiltra-

where *y*(*t*) is the signal (sensitive emission) on the output of SCA and *x*(*t*) is the signal on the input of SCA. Very often on the output of receiver, a module *y*"(*t*) of

\_\_\_\_\_\_\_\_\_\_\_ *x*(*t* − ∆*t*) − *x*(*t*)

<sup>∆</sup>*<sup>t</sup>* , (1)

emission and space between these two mentioned elements (**Figure 4**).

∆*t*→0

tion process' point of view. The SCA is described by formula.

*y*′(*t*) = lim

from the device and the susceptibility of the device to electromagnetic disturbance—is the use of differential-mode signals. This solution protecting *Electromagnetic Eavesdropping DOI: http://dx.doi.org/10.5772/intechopen.86478*

#### **Figure 2.**

*Recent Trends in Communication Networks*

standards are the object of the research on solutions that effectively protect processed graphical data. Most frequently, the only solutions used for electromagnetic data protection are those design-related which decrease the level of unwanted

*Examples of reconstructed images for sources of sensitive emissions in the form of (a) VGA standard (receiving frequency fo = 681 MHz, measure bandwidth BW = 10 MHz) and (b) DVI standard (receiving frequency* 

Another no less dangerous source of electromagnetic emission, formidable from the point of view of the possibility of conducting electromagnetic "watch", are computer laser printers [15, 16]. They translate the electronic form of processed data into graphical form during the printing process. As with every electronic device, printers are sources of electromagnetic emanations [17]. Besides control signals, which carry no information (e.g. directing the operation of stepper motors or heaters), there are other signals (useful signals) that are correlated with the information being processed. Such emissions are called "sensitive" or "valuable" or "compromising" emanations from the point of view of electromagnetic protection of processed information. Processed data

Organizational and technical solutions are the most often used methods for limiting infiltration sensitivity of devices. Technical solutions are limited to changes in

emissions at a source. Many people consider which standard is safer.

may be information displayed on a computer screen or printed (**Figure 2**).

**40**

**Figure 1.**

*fo = 852 MHz, measure bandwidth BW = 50 MHz).*

*Sources of sensitive emissions on an example of a personal computer (PC).*

the design of devices that typically increase the cost of such devices and sometimes limit their functionality. Therefore, it is desirable to find solutions that avoid these drawbacks and at the same time allow "safe" processing of classified information. An example of an organizational solution might be the establishment of a "control zone" around susceptible devices, relying on distance to attenuate signals below levels that can be received outside the control zone. Both solutions aren't acceptable by users of these devices.

Note that the costs of acquiring a single computer set, referred to as TEMPEST class, are an expense of several of thousand dollars. That is why "software solutions", based on the use of "safe fonts", are mentioned more and more often. As shown by the results of conducted studies, classified information processed with the use of them becomes safe for sources in both the form of video track standard VGA and DVI and video track of laser printers. In the case of laser printers, one technical method that is commonly used in the field of electromagnetic compatibility—both to reduce the amount of electromagnetic interference emitted from the device and the susceptibility of the device to electromagnetic disturbance—is the use of differential-mode signals. This solution protecting printed information was described in [18].

Currently there are new searched methods based on software solutions. Such solutions could change the character of radiation source. The methods could be used to support other solutions or they could be used alone. One of them is safe fonts [19, 20]. Very often such fonts are called TEMPEST fonts. There are three proposed sets of such fonts: Symmetrical Safe font, Asymmetrical Safe font and Simply Safe font (**Figure 3**). These sets of fonts differ in properties of construction of font characters.

Usefulness of these fonts was confirmed from electromagnetic protection's point of view for analogue graphic standard VGA, digital graphic standard DVI and laser printers. The collections of these fonts also are resistant to optical character recognition (OCR).

A side-channel attack (SCA) plays a very important role in the electromagnetic eavesdropping process. The SCA is built from a source of emission, a receiver of emission and space between these two mentioned elements (**Figure 4**).

This type of SCA has the characteristics of a high-pass filter, which is an important property from the protection of information against electromagnetic infiltration process' point of view. The SCA is described by formula.

$$y'(t) = \lim\_{\Delta t \to 0} \frac{x(t - \Delta t) - x(t)}{\Delta t},\tag{1}$$

where *y*(*t*) is the signal (sensitive emission) on the output of SCA and *x*(*t*) is the signal on the input of SCA. Very often on the output of receiver, a module *y*"(*t*) of the signal *y*(*t*) exists:

$$\mathcal{Y}^{\prime\prime}(t) = \left| \lim\_{\Delta t \to 0} \frac{\mathbf{x}(t - \Delta t) - \mathbf{x}(t)}{\Delta t} \right|. \tag{2}$$

In real conditions we cannot forget about noises *s*(*t*) and electromagnetic disturbances *d*(*t*) which could disturb sensitive emissions *y*"'(*t*) measured on the output of the SCA [21]. Then.

$$\mathcal{X}^{'(t)} = \mathcal{X}(t) + \mathfrak{s}(t) + d(t),\tag{3}$$

$$\mathcal{Y}^{\prime\prime\prime}(t) = \left| \lim\_{\Delta t \to 0} \frac{\mathbf{x}^{\prime}(t - \Delta t) - \mathbf{x}^{\prime}(t)}{\Delta t} \right|. \tag{4}$$

On the output of SCA, only vertical and diagonal edges (rising edges and falling edges of pulses of electrical video signals, as on **Figure 1a**) are visible on reconstructed images. There are no visible horizontal edges. It is a very important feature from electromagnetic penetration process' point of view.

**Figure 3.**

*Examples of characters of safe fonts: (a) symmetrical safe font, (b) asymmetrical safe font and (c) simply safe font.*

**Figure 4.** *A scheme of side-channel attack.*

#### **2. TEMPEST fonts**

#### **2.1 Introduction**

An important element of daily processing of text information is the use of computer fonts. Traditional Arial and Times New Roman fonts are the most

**43**

**Figure 5.**

*Electromagnetic Eavesdropping*

characteristics of this signal.

process as well as OCR process.

**2.2 Symmetrical safe font**

**2.3 Asymmetrical safe font**

*DOI: http://dx.doi.org/10.5772/intechopen.86478*

popular. Characters of these fonts have decorative elements such as an ear, a bowl, an eye, a serif, a tail, a terminal, a bracket, a loop, etc. The characters are oval, and angles between the individual elements of characters aren't equal to 90° [22, 23]. In addition, the widths of lines building characters are variable. During the processing of text data, each character of font has its representation in the form of electrical signal. This signal is transmitted from a computer to a screen or to a laser printer. In this case, this signal becomes a source of electromagnetic emissions which have

• Lines building the characters intersect at a right angle (each character is built

The safe fonts are fully usable. They are resistant to electromagnetic infiltration

The traditional fonts do not meet the mentioned requirements (**Figure 5**).

The font characters are devoid of decorative and diagonal elements. The lines building the characters intersect at a right angle. Each character is built from lines about two widths (**Figure 6**). Wider lines are vertical lines of the character; thinner lines are horizontal lines of the character. Simultaneously the right proportions of the line width and the clearance of each character of the font are maintained. It means that the distance between two wider vertical lines is equal to the width of vertical line. The corresponding characters have ascender and descender. There aren't unnecessary decorative elements. This makes that the characters of the font are similar with each

Similar to the Symmetrical Safe font, this font could be used in printing process and computer techniques. The characters of this font are devoid of decorative and diagonal elements. The lines building the characters intersect at a right angle. Each character is also built from lines about two widths (**Figure 7**). However, the location of the lines in the characters is different than for the Symmetrical Safe font. Wider lines are vertical lines but only as a left part of the character. Thinner lines appear as horizontal lines of the character and as a right element of the character. It means that the width of wider vertical line is the equal sum of distance between vertical lines and width of thinner vertical line. Simultaneously the right proportions of the width of the lines and the clearance of each character of font are maintained. The

Safe fonts are designed according to safety criteria [24, 25]:

• Font characters are devoid of decorative and diagonal elements.

• General contour of characters of safe font has a rectangle shape.

other with high values of correlation coefficient between characters.

corresponding characters have ascender and descender.

*Distinctive features of times new Roman font on an example of "a" character.*

only from vertical and horizontal lines).

#### *Electromagnetic Eavesdropping DOI: http://dx.doi.org/10.5772/intechopen.86478*

*Recent Trends in Communication Networks*

*x*′(*t*)

*y*′′′(*t*) = | lim

from electromagnetic penetration process' point of view.

of the SCA [21]. Then.

*y*′′(*t*) = | lim

∆*t*→0

∆*t*→0

edges of pulses of electrical video signals, as on **Figure 1a**) are visible on reconstructed images. There are no visible horizontal edges. It is a very important feature

An important element of daily processing of text information is the use of computer fonts. Traditional Arial and Times New Roman fonts are the most

\_\_\_\_\_\_\_\_\_\_\_ *x*(*t* − ∆*t*) − *x*(*t*)

*x*′(*t* − ∆*t*) − *x*′(*t*)

In real conditions we cannot forget about noises *s*(*t*) and electromagnetic disturbances *d*(*t*) which could disturb sensitive emissions *y*"'(*t*) measured on the output

On the output of SCA, only vertical and diagonal edges (rising edges and falling

*Examples of characters of safe fonts: (a) symmetrical safe font, (b) asymmetrical safe font and (c) simply safe font.*

<sup>∆</sup>*<sup>t</sup>* |. (2)

= *x*(*t*) + *s*(*t*) + *d*(*t*), (3)

\_\_\_\_\_\_\_\_\_\_\_\_\_ <sup>∆</sup>*<sup>t</sup>* |. (4)

**42**

**2. TEMPEST fonts**

*A scheme of side-channel attack.*

**2.1 Introduction**

**Figure 4.**

**Figure 3.**

popular. Characters of these fonts have decorative elements such as an ear, a bowl, an eye, a serif, a tail, a terminal, a bracket, a loop, etc. The characters are oval, and angles between the individual elements of characters aren't equal to 90° [22, 23]. In addition, the widths of lines building characters are variable. During the processing of text data, each character of font has its representation in the form of electrical signal. This signal is transmitted from a computer to a screen or to a laser printer. In this case, this signal becomes a source of electromagnetic emissions which have characteristics of this signal.

Safe fonts are designed according to safety criteria [24, 25]:


The safe fonts are fully usable. They are resistant to electromagnetic infiltration process as well as OCR process.

The traditional fonts do not meet the mentioned requirements (**Figure 5**).

#### **2.2 Symmetrical safe font**

The font characters are devoid of decorative and diagonal elements. The lines building the characters intersect at a right angle. Each character is built from lines about two widths (**Figure 6**). Wider lines are vertical lines of the character; thinner lines are horizontal lines of the character. Simultaneously the right proportions of the line width and the clearance of each character of the font are maintained. It means that the distance between two wider vertical lines is equal to the width of vertical line. The corresponding characters have ascender and descender. There aren't unnecessary decorative elements. This makes that the characters of the font are similar with each other with high values of correlation coefficient between characters.

#### **2.3 Asymmetrical safe font**

Similar to the Symmetrical Safe font, this font could be used in printing process and computer techniques. The characters of this font are devoid of decorative and diagonal elements. The lines building the characters intersect at a right angle. Each character is also built from lines about two widths (**Figure 7**). However, the location of the lines in the characters is different than for the Symmetrical Safe font. Wider lines are vertical lines but only as a left part of the character. Thinner lines appear as horizontal lines of the character and as a right element of the character. It means that the width of wider vertical line is the equal sum of distance between vertical lines and width of thinner vertical line. Simultaneously the right proportions of the width of the lines and the clearance of each character of font are maintained. The corresponding characters have ascender and descender.

**Figure 5.** *Distinctive features of times new Roman font on an example of "a" character.*

#### **Figure 6.**

*A construction of characters of symmetrical safe font.*

#### **Figure 7.**

*A construction of characters of asymmetrical safe font.*

#### **Figure 8.**

*A construction of characters of simply safe font.*

#### **2.4 Simply safe font**

The Simply Safe font is the third set of safe fonts. The characters of this font are devoid of decorative and diagonal elements. The lines building the characters intersect at a right angle. Each character is built from lines about one width (**Figure 8**). This feature distinguishes this font from two others. Simultaneously the right proportions of the width of the lines and the clearance of each character of font are maintained. The corresponding characters have ascender and descender.

#### **3. Sensitive emissions and possibilities of reconstruction of primary information**

#### **3.1 Introduction**

To assess sensitive emissions from electromagnetic protection of information's point of view, a lot of tests were carried out. The tests were conducted in special conditions without additional unwanted sources of electromagnetic disturbances [26, 27]. Such conditions exist inside an anechoic chamber (**Figure 9**). Such type of chamber is built from metal sheets. Internal walls of the chamber are covered with special hybrid material. These materials (graphite tiles and so-called cones containing graphite compounds) absorb an energy of electromagnetic waves. There is lack of secondary electromagnetic waves.

Sensitive emissions are measured in the range of frequency from about 100 to 1500 MHz. The upper limit of frequency is pointed by digital video standard. For analogue standard the upper limit is equal to about 800 MHz. Of course, it depends on the parameters of image displayed on a screen.

Corresponding tests were carried out to show the effectiveness of the tempest fonts in the protection of information against electromagnetic penetration process. In

**45**

*Electromagnetic Eavesdropping*

*DOI: http://dx.doi.org/10.5772/intechopen.86478*

Parameters of displayed image:

*A view of anechoic chamber with hybrid material.*

• Resolution (1024 × 768/60 Hz)

• Size of font characters (22 p.)

Very often a coefficient of character error rate (CER)

*CER* = \_\_\_\_

tion [28–30] which was shown on **Figure 11**.

• Magnification (600%)

**Figure 9.**

were shown on **Table 1**.

the frequency domain.

**3.2 VGA standard**

analyses we can use a visual method. It applies to images obtained based on sensitive emissions measured on corresponding frequencies (**Figure 10**, selected frequencies).

Analyzing the images we have to remember the size of characters and the magnification. For typical parameters, i.e. 12 p. of the size and 200% of the magnification, the recognition process is much harder and even impossible for safe fonts.

*m* + *k*

where *u* is the number of characters looked for in an analyzed image, *m* is the number of characters incorrectly recognized, *n* is the number of characters correctly recognized, *k* is the number of unrecognized but looked for characters in an analyzed image (*k = u – n*), and *q* is the number of all characters existing in an analyzed image and is used for precise assessment. The values of this parameter

Signal compatible with the VGA standard has an amplitude ranging from 0 to 0.7 V, and the maximum number of signal levels, when using all 8-bits to encode the brightness of each component of the pixel's color, is equal to 256. This means 16, 777, 216 colors are possible to be displayed with the red, green and blue (RGB) color palette and correspond to the true color (24-bits) graphic card work mode. Video signal of the VGA standard has a characteristic structure which enables to distinguish unique signatures, which allow its identification, both in the time and

A sensitive emission was measured among other things on the frequency equal to 417 MHz (**Figure 10a**). The emission allowed to reconstructed primary informa-

*<sup>q</sup>* <sup>=</sup> \_\_\_\_\_\_\_\_ *m* + (*u* − *n*)

*<sup>q</sup>* , (5)

*Recent Trends in Communication Networks*

*A construction of characters of symmetrical safe font.*

*A construction of characters of asymmetrical safe font.*

*A construction of characters of simply safe font.*

of secondary electromagnetic waves.

on the parameters of image displayed on a screen.

The Simply Safe font is the third set of safe fonts. The characters of this font are devoid of decorative and diagonal elements. The lines building the characters intersect at a right angle. Each character is built from lines about one width (**Figure 8**). This feature distinguishes this font from two others. Simultaneously the right proportions of the width of the lines and the clearance of each character of font are maintained. The corresponding characters have ascender and

**3. Sensitive emissions and possibilities of reconstruction of primary** 

To assess sensitive emissions from electromagnetic protection of information's point of view, a lot of tests were carried out. The tests were conducted in special conditions without additional unwanted sources of electromagnetic disturbances [26, 27]. Such conditions exist inside an anechoic chamber (**Figure 9**). Such type of chamber is built from metal sheets. Internal walls of the chamber are covered with special hybrid material. These materials (graphite tiles and so-called cones containing graphite compounds) absorb an energy of electromagnetic waves. There is lack

Sensitive emissions are measured in the range of frequency from about 100 to 1500 MHz. The upper limit of frequency is pointed by digital video standard. For analogue standard the upper limit is equal to about 800 MHz. Of course, it depends

Corresponding tests were carried out to show the effectiveness of the tempest fonts in the protection of information against electromagnetic penetration process. In

**44**

**Figure 8.**

**Figure 7.**

**Figure 6.**

descender.

**information**

**3.1 Introduction**

**2.4 Simply safe font**

**Figure 9.** *A view of anechoic chamber with hybrid material.*

analyses we can use a visual method. It applies to images obtained based on sensitive emissions measured on corresponding frequencies (**Figure 10**, selected frequencies).

Parameters of displayed image:


Analyzing the images we have to remember the size of characters and the magnification. For typical parameters, i.e. 12 p. of the size and 200% of the magnification, the recognition process is much harder and even impossible for safe fonts. Very often a coefficient of character error rate (CER)

$$\text{CER} = \frac{m+k}{q} = \frac{m+(n-n)}{q},\tag{5}$$

where *u* is the number of characters looked for in an analyzed image, *m* is the number of characters incorrectly recognized, *n* is the number of characters correctly recognized, *k* is the number of unrecognized but looked for characters in an analyzed image (*k = u – n*), and *q* is the number of all characters existing in an analyzed image and is used for precise assessment. The values of this parameter were shown on **Table 1**.

#### **3.2 VGA standard**

Signal compatible with the VGA standard has an amplitude ranging from 0 to 0.7 V, and the maximum number of signal levels, when using all 8-bits to encode the brightness of each component of the pixel's color, is equal to 256. This means 16, 777, 216 colors are possible to be displayed with the red, green and blue (RGB) color palette and correspond to the true color (24-bits) graphic card work mode.

Video signal of the VGA standard has a characteristic structure which enables to distinguish unique signatures, which allow its identification, both in the time and the frequency domain.

A sensitive emission was measured among other things on the frequency equal to 417 MHz (**Figure 10a**). The emission allowed to reconstructed primary information [28–30] which was shown on **Figure 11**.

**Figure 10.**

*Levels of electromagnetic emissions measured in frequency domain: (a) VGA standard (b) DVI standard.*

#### **3.3 DVI standard**

DVI standard specification, developed by the Digital Display Working Group (DDWG), gathering many leading hardware manufacturers, was published in 1999 [11]. In this encoding method, 8-bit RGB data are converted in the graphic card's transmitter into a 10-bit format using transition minimalization and constant component balancing (DC-balanced sequence) techniques. However, that does not mean that transition-minimized differential signalling (TMDS) encoding and extension DVI standard are impervious to electromagnetic eavesdropping. An electric signal in the form of a series of zeros and ones is a source of sensitive emissions. Radiated emission propagates in the space surrounding the source and is subjected to the effects of a highpass filter (SCA). As a result of the original signal (TMDS) distortions of this kind, the form of sensitive emission signal becomes usable for electromagnetic eavesdropping.

Time series of signals responsible for transmission of information on pixels' color components in DVI standard show that the DVI interface retains the framing principles of signals from the VGA interface. Bit (impulse) series corresponding to individual pixels of the image are transmitted in accordance with the TMDS clock in

**47**

**Figure 11.**

strictly defined time periods. Those periods reflect horizontal and vertical synchro-

*Fragments of reconstructed images including characters of (a) symmetrical safe font, (b) asymmetrical safe* 

nization signals of the analogue VGA signal.

*font, (c) simply safe font and (d) Arial font.*

*Electromagnetic Eavesdropping*

**Character Arial** 

*VGA standard*

*DVI* (*HDMI*) *standard*

**Table 1.**

*DOI: http://dx.doi.org/10.5772/intechopen.86478*

**font**

**Times new roman font**

*Values of character error rate for selected characters of traditional and safe fonts.*

**Symmetrical safe font**

d 0 0 0 371 1 e 1 6 122 354 48 i 43 17 1 128 115 o 3 9 339 212 174 u 1 2 369 45 107

d 4 4 25 95 72 e 4 4 140 45 65 i 46 14 42 15 153 o 36 7 60 236 351 u 7 3 104 562 6

**Asymmetrical safe font**

**Simply safe font** *Electromagnetic Eavesdropping DOI: http://dx.doi.org/10.5772/intechopen.86478*


**Table 1.**

*Recent Trends in Communication Networks*

**46**

**3.3 DVI standard**

**Figure 10.**

DVI standard specification, developed by the Digital Display Working Group (DDWG), gathering many leading hardware manufacturers, was published in 1999 [11]. In this encoding method, 8-bit RGB data are converted in the graphic card's transmitter into a 10-bit format using transition minimalization and constant component balancing (DC-balanced sequence) techniques. However, that does not mean that transition-minimized differential signalling (TMDS) encoding and extension DVI standard are impervious to electromagnetic eavesdropping. An electric signal in the form of a series of zeros and ones is a source of sensitive emissions. Radiated emission propagates in the space surrounding the source and is subjected to the effects of a highpass filter (SCA). As a result of the original signal (TMDS) distortions of this kind, the form of sensitive emission signal becomes usable for electromagnetic eavesdropping. Time series of signals responsible for transmission of information on pixels' color components in DVI standard show that the DVI interface retains the framing principles of signals from the VGA interface. Bit (impulse) series corresponding to individual pixels of the image are transmitted in accordance with the TMDS clock in

*Levels of electromagnetic emissions measured in frequency domain: (a) VGA standard (b) DVI standard.*

*Values of character error rate for selected characters of traditional and safe fonts.*

#### **Figure 11.**

*Fragments of reconstructed images including characters of (a) symmetrical safe font, (b) asymmetrical safe font, (c) simply safe font and (d) Arial font.*

strictly defined time periods. Those periods reflect horizontal and vertical synchronization signals of the analogue VGA signal.

#### **Figure 12.**

*Fragments of reconstructed images including characters of (a) symmetrical safe font, (b) asymmetrical safe font, (c) simply safe font and (d) Arial font.*

A sensitive emission was measured among other things on the frequency of 926 MHz (**Figure 10b**). The emission allowed to reconstructed primary information which was shown in **Figure 12**.

#### **4. Conclusions**

In this chapter the possibilities of electromagnetic penetration for sources of sensitive emissions in the form of analogue (VGA) and digital (DVI, HDMI) video standards were described. A solution, which protects processed text information, was shown. The solution is based on three sets of tempest font: Symmetrical Safe font, Asymmetrical Safe font and Simply Safe font.

Each font is free from distinctive features. Characters of fonts are characterized by very high level of similarity. Values of correlation coefficient are more than 0.7, but the level of legibility is acceptable by potential users. The high level of similarity of characters on the input of SCA causes that on the output of SCA the recognition of characters is very difficult. For traditional fonts (e.g. Arial or Times New Roman), the infiltration process is possible and data acquisition is not difficult (**Figure 13**) [31, 32]. Additionally the tempest fonts counteract the penetration process of laser printers. Therefore the new solution is called as a universal solution.

An application of new solution is very easy. Only an installation corresponding set font on a computer is necessary [19]. The solution can replace present solutions basing on shielding (very heavy elements), filtering, grounding and so on.

The safe fonts obtained protection of the Polish Office Pattern in the form of Industrial Design (No. 24487, **Figure 14a**) and Patent (No. 231691, **Figure 14b**) [24, 25].

**49**

**Conflict of interest**

**Figure 14.**

The author declares no conflict of interest of this book chapter.

*A certificate of Industrial Design (a) and a Patent (b) for safe fonts.*

*Example of reconstructed image for text size 14 p. and magnification 160% written using safe and traditional fonts.*

*Electromagnetic Eavesdropping*

**Figure 13.**

*DOI: http://dx.doi.org/10.5772/intechopen.86478*

#### *Electromagnetic Eavesdropping DOI: http://dx.doi.org/10.5772/intechopen.86478*

#### **Figure 13.**

*Recent Trends in Communication Networks*

which was shown in **Figure 12**.

*font, (c) simply safe font and (d) Arial font.*

font, Asymmetrical Safe font and Simply Safe font.

**4. Conclusions**

**Figure 12.**

A sensitive emission was measured among other things on the frequency of 926 MHz (**Figure 10b**). The emission allowed to reconstructed primary information

*Fragments of reconstructed images including characters of (a) symmetrical safe font, (b) asymmetrical safe* 

In this chapter the possibilities of electromagnetic penetration for sources of sensitive emissions in the form of analogue (VGA) and digital (DVI, HDMI) video standards were described. A solution, which protects processed text information, was shown. The solution is based on three sets of tempest font: Symmetrical Safe

Each font is free from distinctive features. Characters of fonts are characterized by very high level of similarity. Values of correlation coefficient are more than 0.7, but the level of legibility is acceptable by potential users. The high level of similarity of characters on the input of SCA causes that on the output of SCA the recognition of characters is very difficult. For traditional fonts (e.g. Arial or Times New Roman), the infiltration process is possible and data acquisition is not difficult (**Figure 13**) [31, 32]. Additionally the tempest fonts counteract the penetration process of laser printers. Therefore the new solution is called as a universal solution. An application of new solution is very easy. Only an installation corresponding set font on a computer is necessary [19]. The solution can replace present solutions

basing on shielding (very heavy elements), filtering, grounding and so on. The safe fonts obtained protection of the Polish Office Pattern in the form of Industrial Design (No. 24487, **Figure 14a**) and Patent (No. 231691, **Figure 14b**) [24, 25].

**48**

*Example of reconstructed image for text size 14 p. and magnification 160% written using safe and traditional fonts.*

**Figure 14.** *A certificate of Industrial Design (a) and a Patent (b) for safe fonts.*

#### **Conflict of interest**

The author declares no conflict of interest of this book chapter.

*Recent Trends in Communication Networks*

#### **Author details**

Ireneusz Kubiak Military Communication Institute, Poland

\*Address all correspondence to: i.kubiak@wil.waw.pl

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**51**

*Electromagnetic Eavesdropping*

**References**

*DOI: http://dx.doi.org/10.5772/intechopen.86478*

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[8] Boitan A, Bărtușică R, Halunga S, Bîndar V. Video signal recovery from the laser printer LCD display, Proceedings Volume 10977, Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies IX, 2018. Event: Advanced Topics in Optoelectronics, Microelectronics and Nanotechnologies IX, 2018, Constanta, Romania. DOI:

[9] Butnariu V, Trip B, Macovei A, Rosu G,

Halunga S. Detection of electromagnetic emissions transmitted on the power line through electrical conduction. In: International Conference on Applied and Theoretical Electricity (ICATE 2018); DOI: 10.1109/

Boitan A, Halunga S. Power line compromising emanations analysis. Annals of the University of Craiova, Electrical Engineering Series. Vol. 48. 2018

[10] Macovei A, Boitan A, Trip B,

[11] Digital Visual Interface DVI Revision 1.0. Available from: http:// www.cs.unc.edu/~stc/FAQs/Video/

[12] HDMI Specification Ver.1.3a. Available from: https://www.hdmi.org/ manufacturer/specification.aspx

[13] Jun S, Yongacoglu A, Degang S, Dong W. Computer LCD recognition based on the compromising emanations

in cyclic frequency domain. In: IEEE International Symposium on Electromagnetic Compatibility, Ottawa, Canada; 25-29 July 2016;

[14] Kubiak I. Video signal level (colour intensity) and effectiveness of

2016;**9**:09-19

10.1117/12.2324759

ICATE.2018.8551437

dvi\_spec-V1\_0.pdf

pp. 164-169

2013;**E96-B**(10):2639-2649. DOI: 10.1587/transcom.E96.B.2639

[2] Nan Z, Yinghua L, Qiang C, Yiying W. Investigation of unintentional video emanations from a VGA connector in the desktop computers. IEEE Transactions on Electromagnetic Compatibility. 2017;**59**(6):1826-1834

[3] Jinming L, Jiemin Z, Taikang L, Yongmei L. The reconstitution of LCD compromising emanations based on wavelet denoising. In: 12th International Conference on Computer Science and Education (ICCSE); 22-25 August 2017; Houston, USA. pp. 294-297. DOI:

10.1109/ICCSE.2017.8085505

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elk-1701-128

CIS.2011.146

[4] Kubiak I. Laser printer as a source of sensitive emissions. Turkish Journal of Electrical Engineering and Computer Sciences. 2018;**26**(3):1354-1366. DOI:

[5] Kubiak I. LED printers and safe fonts as an effective protection against the formation of unwanted emission. Turkish Journal of Electrical Engineering and Computer Sciences. 2017;**25**(5):4268-4279. DOI: 10.3906/

[6] Litao W, Bin Y. Analysis and measurement on the electromagnetic compromising emanations of computer keyboards. In: Seventh International Conference on Computational

[7] Tokarev AB, Pitolin VM,

of informative components of compromising electromagnetic

Intelligence and Security; 3-4 December 2011; Sanya. pp. 640-643. DOI: 10.1109/

Beletskaya SY, Bulgakov AV. Detection

### **References**

*Recent Trends in Communication Networks*

**50**

**Author details**

Ireneusz Kubiak

Military Communication Institute, Poland

provided the original work is properly cited.

\*Address all correspondence to: i.kubiak@wil.waw.pl

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

[1] Lee HK, Kim JH, Kim SC. Emission security limits for compromising emanations using electromagnetic emanation security channel analysis. IEICE Transactions on Communications. 2013;**E96-B**(10):2639-2649. DOI: 10.1587/transcom.E96.B.2639

[2] Nan Z, Yinghua L, Qiang C, Yiying W. Investigation of unintentional video emanations from a VGA connector in the desktop computers. IEEE Transactions on Electromagnetic Compatibility. 2017;**59**(6):1826-1834

[3] Jinming L, Jiemin Z, Taikang L, Yongmei L. The reconstitution of LCD compromising emanations based on wavelet denoising. In: 12th International Conference on Computer Science and Education (ICCSE); 22-25 August 2017; Houston, USA. pp. 294-297. DOI: 10.1109/ICCSE.2017.8085505

[4] Kubiak I. Laser printer as a source of sensitive emissions. Turkish Journal of Electrical Engineering and Computer Sciences. 2018;**26**(3):1354-1366. DOI: 10.3906/elk-1704-263

[5] Kubiak I. LED printers and safe fonts as an effective protection against the formation of unwanted emission. Turkish Journal of Electrical Engineering and Computer Sciences. 2017;**25**(5):4268-4279. DOI: 10.3906/ elk-1701-128

[6] Litao W, Bin Y. Analysis and measurement on the electromagnetic compromising emanations of computer keyboards. In: Seventh International Conference on Computational Intelligence and Security; 3-4 December 2011; Sanya. pp. 640-643. DOI: 10.1109/ CIS.2011.146

[7] Tokarev AB, Pitolin VM, Beletskaya SY, Bulgakov AV. Detection of informative components of compromising electromagnetic

emanations of computer hardware. International Journal of Computer Technology and Applications. 2016;**9**:09-19

[8] Boitan A, Bărtușică R, Halunga S, Bîndar V. Video signal recovery from the laser printer LCD display, Proceedings Volume 10977, Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies IX, 2018. Event: Advanced Topics in Optoelectronics, Microelectronics and Nanotechnologies IX, 2018, Constanta, Romania. DOI: 10.1117/12.2324759

[9] Butnariu V, Trip B, Macovei A, Rosu G, Boitan A, Halunga S. Power line compromising emanations analysis. Annals of the University of Craiova, Electrical Engineering Series. Vol. 48. 2018

[10] Macovei A, Boitan A, Trip B, Halunga S. Detection of electromagnetic emissions transmitted on the power line through electrical conduction. In: International Conference on Applied and Theoretical Electricity (ICATE 2018); DOI: 10.1109/ ICATE.2018.8551437

[11] Digital Visual Interface DVI Revision 1.0. Available from: http:// www.cs.unc.edu/~stc/FAQs/Video/ dvi\_spec-V1\_0.pdf

[12] HDMI Specification Ver.1.3a. Available from: https://www.hdmi.org/ manufacturer/specification.aspx

[13] Jun S, Yongacoglu A, Degang S, Dong W. Computer LCD recognition based on the compromising emanations in cyclic frequency domain. In: IEEE International Symposium on Electromagnetic Compatibility, Ottawa, Canada; 25-29 July 2016; pp. 164-169

[14] Kubiak I. Video signal level (colour intensity) and effectiveness of electromagnetic infiltration. Bulletin of the Polish Academy of Sciences— Technical Sciences. 2016;**64**:207-2018. DOI: 10.1515/bpasts-2016-0023

[15] Kubiak I. The influence of the structure of useful signal on the efficacy of sensitive emission of laser printers. Measurement. 2018;**119**:63-76. DOI: 10.1016/j. measurement.2018.01.055

[16] Loughry J, Umphress DA. Information leakage from optical emanations. ACM Transactions on Information and System Security. 2002;**5**:262-289

[17] Michael JM. The pentagon worries that spies can see its computer screens, someone could watch what's on your VDT. The Wall Street Journal. 2000;**8**:1-2

[18] Kubiak I, Loughry J. LED Arrays of Laser Printers as Sources of Valuable Emissions for Electromagnetic Penetration Process, arXiv:1808.03007v1 [cs.CR]; 9 August 2018

[19] Kubiak I. TEMPEST font counteracting a non-invasive acquisition of text data. Turkish Journal of Electrical Engineering and Computer Sciences. 2018;**26**(1):582-592. DOI: 10.3906/elk-1704-9

[20] Kubiak I. Influence of the method of colors on levels of electromagnetic emissions from video standards. IEEE Transactions on Electromagnetic Compatibility. 2018:1-9. DOI: 10.1109/ TEMC.2018.2881304

[21] Song TL, Jeong YR, Jo HS, Yook JG. Noise-jamming effect as a countermeasure against TEMPEST during high-speed signaling. IEEE Transactions on Electromagnetic Compatibility. 2015;**57**(6):1491-1500

[22] Shainir A, Rappoport A. Extraction of typographic elements from outline

representations of fonts. Computer Graphics Forum. 1996;**15**(3):259-268. DOI: 10.1111/1467-8659.1530259

[23] Nanxuan Z, Ying C, Lau WH. Modeling fonts in context: Font prediction on web designs. Computer Graphics Forum. 2018;**37**(7):385-395. DOI: 10.1111/cgf.13576

[24] Kubiak I. Industrial Design No. 24487, Polish Pattern Office, 10 September 2018

[25] Kubiak I. Pattern No. P.408372 Method for protecting transmission of information, Polish Pattern Office, 3 December 2018

[26] Song TL, Jong-Gwan Y. Study of jamming countermeasure for electromagnetically leaked digital video signals. In: IEEE International Symposium on Electromagnetic Compatibility; 1-4 September 2014; DOI: 10.1109/EMCEurope.2014.6931078

[27] Yuan K, Grassi F, Spadacini G, Pignari SA. Crosstalk-sensitive loops and reconstruction algorithms to eavesdrop digital signals transmitted along differential interconnects, IEEE Transactions on Electromagnetic Compatibility. 2017;**59**(1):256-265

[28] Juric I, Nedeljkovic U, Novakovic D, Pincjer I. Visual experience of noise in digital images. Tehnicki Vjesnik-Technical Gazette. 2016;**23**(5):1463-1467

[29] Lorencs A, Sinica-Sinavskis J. One method of image processing and its numerical analysis. Elektronika IR Elektrotechnika. 2010;**103**(7):25-30

[30] Manson J, Schaefer S. Wavelet rasterization. Computer Graphics Forum. 2011;**30**(2):395-404. DOI: 10.1111/j.1467-8659.2011.01887.x

[31] Zoric A, Perisic D, Obradovic S, Spalevic P. Virtual multisensors data

**53**

*Electromagnetic Eavesdropping*

eee.116.10.879

2010;**105**(9):97-100

*DOI: http://dx.doi.org/10.5772/intechopen.86478*

acquisition and analysis system design. Elektronika IR Elektrotechnika. 2011;**116**(10):49-54. DOI: 10.5755/j01.

[32] Kuusik A, Reilent E, Lõõbas I, Luberg A. Data acquisition software architecture for patient monitoring devices. Elektronika IR Elektrotechnika. *Electromagnetic Eavesdropping DOI: http://dx.doi.org/10.5772/intechopen.86478*

*Recent Trends in Communication Networks*

electromagnetic infiltration. Bulletin of the Polish Academy of Sciences— Technical Sciences. 2016;**64**:207-2018. DOI: 10.1515/bpasts-2016-0023

representations of fonts. Computer Graphics Forum. 1996;**15**(3):259-268. DOI: 10.1111/1467-8659.1530259

[23] Nanxuan Z, Ying C, Lau WH. Modeling fonts in context: Font prediction on web designs. Computer Graphics Forum. 2018;**37**(7):385-395.

[24] Kubiak I. Industrial Design No. 24487, Polish Pattern Office, 10

[25] Kubiak I. Pattern No. P.408372 Method for protecting transmission of information, Polish Pattern Office, 3

[26] Song TL, Jong-Gwan Y. Study of jamming countermeasure for electromagnetically leaked digital video signals. In: IEEE International Symposium on Electromagnetic Compatibility; 1-4 September 2014; DOI: 10.1109/EMCEurope.2014.6931078

[27] Yuan K, Grassi F, Spadacini G, Pignari SA. Crosstalk-sensitive loops and reconstruction algorithms to eavesdrop digital signals transmitted along differential interconnects, IEEE Transactions on Electromagnetic Compatibility. 2017;**59**(1):256-265

[28] Juric I, Nedeljkovic U, Novakovic D, Pincjer I. Visual experience of noise in digital images. Tehnicki Vjesnik-Technical Gazette. 2016;**23**(5):1463-1467

[29] Lorencs A, Sinica-Sinavskis J. One method of image processing and its numerical analysis. Elektronika IR Elektrotechnika. 2010;**103**(7):25-30

[30] Manson J, Schaefer S. Wavelet rasterization. Computer Graphics Forum. 2011;**30**(2):395-404. DOI: 10.1111/j.1467-8659.2011.01887.x

[31] Zoric A, Perisic D, Obradovic S, Spalevic P. Virtual multisensors data

DOI: 10.1111/cgf.13576

September 2018

December 2018

[15] Kubiak I. The influence of the structure of useful signal on the efficacy of sensitive emission of laser printers. Measurement. 2018;**119**:63-76. DOI: 10.1016/j. measurement.2018.01.055

[16] Loughry J, Umphress DA. Information leakage from optical emanations. ACM Transactions on Information and System Security.

[17] Michael JM. The pentagon worries that spies can see its computer screens, someone could watch what's on your VDT. The Wall Street Journal.

[18] Kubiak I, Loughry J. LED Arrays of Laser Printers as Sources of Valuable Emissions for Electromagnetic

Penetration Process, arXiv:1808.03007v1

counteracting a non-invasive acquisition

[20] Kubiak I. Influence of the method of colors on levels of electromagnetic emissions from video standards. IEEE Transactions on Electromagnetic Compatibility. 2018:1-9. DOI: 10.1109/

[22] Shainir A, Rappoport A. Extraction of typographic elements from outline

2002;**5**:262-289

2000;**8**:1-2

[cs.CR]; 9 August 2018

10.3906/elk-1704-9

TEMC.2018.2881304

[21] Song TL, Jeong YR, Jo HS, Yook JG. Noise-jamming effect as a countermeasure against TEMPEST during high-speed signaling. IEEE Transactions on Electromagnetic Compatibility. 2015;**57**(6):1491-1500

[19] Kubiak I. TEMPEST font

of text data. Turkish Journal of Electrical Engineering and Computer Sciences. 2018;**26**(1):582-592. DOI:

**52**

acquisition and analysis system design. Elektronika IR Elektrotechnika. 2011;**116**(10):49-54. DOI: 10.5755/j01. eee.116.10.879

[32] Kuusik A, Reilent E, Lõõbas I, Luberg A. Data acquisition software architecture for patient monitoring devices. Elektronika IR Elektrotechnika. 2010;**105**(9):97-100

**55**

**Chapter 5**

**Abstract**

**1. Introduction**

Geo Location of Mobile Device

The proliferation of cellular network enabled users through various positioning tools to track locations; location information is being continuously captured from mobile phones, where a prototype is created that enables to detect locations based on using the two invariant models for Global Systems for Mobile (GSM) and Universal Mobile Telecommunications System (UMTS). The smartphone application on an Android platform applies the location-sensing run as a background process, and the localization method is based on cell phones. The proposed application is associated with remote server and used to track a smartphone without permissions and Internet. Mobile stores data location information in the database (SQLite) and then transfers it into location API to obtain locations' result implemented in Google Maps. Track a smartphone with fixed identifiers mostly SSN (SIM (Subscriber Identity Module) Serial Number) and IMEI (International Mobile Equipment Identity) derived from an identifying string unique to the user's device. The location result is moderately correct according to the cellular networks GSM

*Bashar M. Nema and Ali Nafaa Jaafar*

and UMTS, which are used for obtaining location information.

exploiting a permanent mobile data link [3].

in mobile device periodically [4].

**Keywords:** tracking, GSM/UMTS, Web services, MySQL, Mobile device

Engineers and researchers have studied the cellular wireless systems offering reliable mobile location estimates for the past few years because of its temporal/ spatial nature and rich context [1]. The mobile device's location has become an important topic in wireless communication despite its low cost and transmission over the control channel owning short response time. The GSM/UMTS can be used to obtain location information without additional external hardware when there is cellular coverage [2]. Location-based services (LBS) for mobile devices have grown rapidly over the past few years and forecasts show similar growth in the future. As the need for tracking mobiles in our daily life is increasing, it became tracking thousands of users periodically; tracking mobiles by cellular networks does not need any hardware change within the core network. Tracking a smartphone is possible by

The mobile device used the location information consisting of Cell Identifier (cell ID), Location Area Code (LAC), Mobile Network Code (MNC), and Mobile Country Code (MCC). The location information is stored inside the SQLite database

The contributions in this chapter can be summarized as follows: we utilize location information for a mobile device that is always available in the cellular network. We create an application of an efficient, easy-to-use, and inexpensive mobile device tracking system; the application provides the better balance between

#### **Chapter 5**

## Geo Location of Mobile Device

*Bashar M. Nema and Ali Nafaa Jaafar*

#### **Abstract**

The proliferation of cellular network enabled users through various positioning tools to track locations; location information is being continuously captured from mobile phones, where a prototype is created that enables to detect locations based on using the two invariant models for Global Systems for Mobile (GSM) and Universal Mobile Telecommunications System (UMTS). The smartphone application on an Android platform applies the location-sensing run as a background process, and the localization method is based on cell phones. The proposed application is associated with remote server and used to track a smartphone without permissions and Internet. Mobile stores data location information in the database (SQLite) and then transfers it into location API to obtain locations' result implemented in Google Maps. Track a smartphone with fixed identifiers mostly SSN (SIM (Subscriber Identity Module) Serial Number) and IMEI (International Mobile Equipment Identity) derived from an identifying string unique to the user's device. The location result is moderately correct according to the cellular networks GSM and UMTS, which are used for obtaining location information.

**Keywords:** tracking, GSM/UMTS, Web services, MySQL, Mobile device

#### **1. Introduction**

Engineers and researchers have studied the cellular wireless systems offering reliable mobile location estimates for the past few years because of its temporal/ spatial nature and rich context [1]. The mobile device's location has become an important topic in wireless communication despite its low cost and transmission over the control channel owning short response time. The GSM/UMTS can be used to obtain location information without additional external hardware when there is cellular coverage [2]. Location-based services (LBS) for mobile devices have grown rapidly over the past few years and forecasts show similar growth in the future. As the need for tracking mobiles in our daily life is increasing, it became tracking thousands of users periodically; tracking mobiles by cellular networks does not need any hardware change within the core network. Tracking a smartphone is possible by exploiting a permanent mobile data link [3].

The mobile device used the location information consisting of Cell Identifier (cell ID), Location Area Code (LAC), Mobile Network Code (MNC), and Mobile Country Code (MCC). The location information is stored inside the SQLite database in mobile device periodically [4].

The contributions in this chapter can be summarized as follows: we utilize location information for a mobile device that is always available in the cellular network. We create an application of an efficient, easy-to-use, and inexpensive mobile device tracking system; the application provides the better balance between location accuracy and battery power. The location information collected during the mobile device roaming between the base stations connects them and the location information enables us to track the mobile device to see the historical location; the application can be used in any place in world covered by cellular network GSM/ UMTS, compared to the information of location with the location APIs to provide the mobile device location. This work offers proactive services of assistance that consequently tell their users when they enter or leave the limits of pre-characterized focal points.

#### **2. Structural GSM/UMTS architecture**

The GSM network structure is divided into a base station subsystem and core network, which is shown in the **Figure 1**. The Base Transceiver Station (BTS) is a main communication area with mobile phones. BTS is linked to the Base Station Controller (BSC), which controls the small set of BTSs. These are linked using an interface known as the (A-bis) interface. The BSC handles the radio channel setup and frequency hopping control and links with a Mobile Switching Center (MSC) via the interface termed the (A interface). The core of a network subsystem is an Authentication Center (AuC) that provides authentication, allowing users to access the network. MSC via interfaces with the Visitor Location Register (VLR) and Home Location Register (HLR) provides location information for a network [5].

The connections originate in the fixed network (Public Switched Telephone Network (PSTN) and Integrated Services Digital Network (ISDN)). The connections have to pass through a dedicated Gateway Mobile Switching Center (GMSC). SIM card Serial Number (SSN) is stored on the SIM card. SIM is inserted to the mobile for providing information around the subscriber. IMEI consists of 15 digit number to identify a mobile phone. IMEI is checked when the mobile phone is

**57**

**Figure 2.**

*Geo Location of Mobile Device*

interface (Iur) between RNCs.

**3. GSM/UMTS-based localization**

portable terminals [5].

NodeBs [7].

*DOI: http://dx.doi.org/10.5772/intechopen.92154*

trying to access the network and compared with an Equipment Identity Register (EIR) database. EIR registers equipment data rather than subscriber data [6]. UMTS network structure is divided into the UMTS Terrestrial Radio Access Network (UTRAN) and core network. UTRAN includes two nodes (the NodeB and Radio Network Controller (RNC)). Each RNC controls one or more NodeBs and is responsible for the control of radio resource parameters of cells managed by those

The Home Subscriber Server (HSS) is a database that communicates directly with a Gateway GPRS Support Node (GGSN) and Service GPRS Support Node (SGSN). SGSN, HSS, and GGSN exchange signaling messages only. Every GGSN can serve multiple SGSNs and every SGSN can serve multiple RNCs. RNC provides an air interface (Iub) between a mobile terminal and a core network, and an air

There are two fundamental differences among GSM and UMTS systems. GSM networks use a methodology of more than one database communication (HLR and VLRs). The neighboring RNCs can ability to communicate with one another. In GSM systems, there is no immediate correspondence between neighboring VLRs and the correspondence is occurring just through the HLR. UMTS systems utilize a methodology with just a single database (HSS) to record the movements of the

Cell-ID (ID) in combination with the MCC, the LAC, and the MNC is the unique identifier of the BTS. The Cell-ID of the BTS has the association with certain Mobile Station (MS), which is known by the mobile device and can be utilized to appraise the position of the mobile device [8]. GSM/UMTS service zone is separated into Location Areas (LAs), where every LA incorporates at least one radio cells. Every

BTS covers the set of cells, each of them identified by the unique Cell-ID (C1, C2, and C3 as shown in **Figure 2**). MS persistently chooses a cell and trades information and signaling traffic with the relating BTS. The cells are assembled into groups, every one of them distinguished by a Location Area Identifier (LAI). So as to maintain a strategic to avoid excessive signaling traffic, as long as the MS is in idle mode, the system knows just the LAI. The network gets mindful of the Cell-ID just when the MS switches into a dedicated mode, in particular when the channel is utilized to

LA and radio cell has a unique identifier named Cell-ID and LAC [9].

*A simplified view of the cellular network and the mobile station is within the cell C3 [10].*

**Figure 1.** *The architecture GSM/UMTS network [5].*

#### *Geo Location of Mobile Device DOI: http://dx.doi.org/10.5772/intechopen.92154*

*Recent Trends in Communication Networks*

**2. Structural GSM/UMTS architecture**

focal points.

location accuracy and battery power. The location information collected during the mobile device roaming between the base stations connects them and the location information enables us to track the mobile device to see the historical location; the application can be used in any place in world covered by cellular network GSM/ UMTS, compared to the information of location with the location APIs to provide the mobile device location. This work offers proactive services of assistance that consequently tell their users when they enter or leave the limits of pre-characterized

The GSM network structure is divided into a base station subsystem and core network, which is shown in the **Figure 1**. The Base Transceiver Station (BTS) is a main communication area with mobile phones. BTS is linked to the Base Station Controller (BSC), which controls the small set of BTSs. These are linked using an interface known as the (A-bis) interface. The BSC handles the radio channel setup and frequency hopping control and links with a Mobile Switching Center (MSC) via the interface termed the (A interface). The core of a network subsystem is an Authentication Center (AuC) that provides authentication, allowing users to access the network. MSC via interfaces with the Visitor Location Register (VLR) and Home Location Register (HLR) provides location information for a network [5]. The connections originate in the fixed network (Public Switched Telephone Network (PSTN) and Integrated Services Digital Network (ISDN)). The connections have to pass through a dedicated Gateway Mobile Switching Center (GMSC). SIM card Serial Number (SSN) is stored on the SIM card. SIM is inserted to the mobile for providing information around the subscriber. IMEI consists of 15 digit number to identify a mobile phone. IMEI is checked when the mobile phone is

**56**

**Figure 1.**

*The architecture GSM/UMTS network [5].*

trying to access the network and compared with an Equipment Identity Register (EIR) database. EIR registers equipment data rather than subscriber data [6].

UMTS network structure is divided into the UMTS Terrestrial Radio Access Network (UTRAN) and core network. UTRAN includes two nodes (the NodeB and Radio Network Controller (RNC)). Each RNC controls one or more NodeBs and is responsible for the control of radio resource parameters of cells managed by those NodeBs [7].

The Home Subscriber Server (HSS) is a database that communicates directly with a Gateway GPRS Support Node (GGSN) and Service GPRS Support Node (SGSN). SGSN, HSS, and GGSN exchange signaling messages only. Every GGSN can serve multiple SGSNs and every SGSN can serve multiple RNCs. RNC provides an air interface (Iub) between a mobile terminal and a core network, and an air interface (Iur) between RNCs.

There are two fundamental differences among GSM and UMTS systems. GSM networks use a methodology of more than one database communication (HLR and VLRs). The neighboring RNCs can ability to communicate with one another. In GSM systems, there is no immediate correspondence between neighboring VLRs and the correspondence is occurring just through the HLR. UMTS systems utilize a methodology with just a single database (HSS) to record the movements of the portable terminals [5].

#### **3. GSM/UMTS-based localization**

Cell-ID (ID) in combination with the MCC, the LAC, and the MNC is the unique identifier of the BTS. The Cell-ID of the BTS has the association with certain Mobile Station (MS), which is known by the mobile device and can be utilized to appraise the position of the mobile device [8]. GSM/UMTS service zone is separated into Location Areas (LAs), where every LA incorporates at least one radio cells. Every LA and radio cell has a unique identifier named Cell-ID and LAC [9].

BTS covers the set of cells, each of them identified by the unique Cell-ID (C1, C2, and C3 as shown in **Figure 2**). MS persistently chooses a cell and trades information and signaling traffic with the relating BTS. The cells are assembled into groups, every one of them distinguished by a Location Area Identifier (LAI). So as to maintain a strategic to avoid excessive signaling traffic, as long as the MS is in idle mode, the system knows just the LAI. The network gets mindful of the Cell-ID just when the MS switches into a dedicated mode, in particular when the channel is utilized to


#### **Table 1.**

*The size range of cell type [10].*

really establish a call. MS always knows the Cell-ID of the cell it is in. The size of a cell may range some meters; accuracy depends on cell size (illustrate in **Table 1**) [10].

#### **4. Android platform**

Android is the platform introduced in 2007 for devices such as smartphones or tablets developed by Google, which is a Linux-based operating system and an open source code designed for touch screen mobile device. The applications were developed in Java language, which allows the software to be freely modified using the Android Studio software development kit (SDK). The SDK contains a comprehensive set of software libraries supported by integrated development environment (IDE), the Android Studio (Android 7.0) to get the cell ID, LAC, MMC, MNC, IMEI, and SSN of an Android mobile, and the database (SQLite) used to store this cell ID, LAC, MMC, and MNC values into periodical processes that are running as background process by applying Android service; Google Maps get from Web service the latitude and longitude in the format of a Java Script Object Notation (JSON) file, the Android mobile support from both Google Maps and third-party developers (remotely connect to a MySQL database) [11].

#### **5. Web service**

A Web service is the software designed to support communication between mobile application and remote server and location API over a network. The Web service designed to provide compute location information results in obtaining specific geographic regions (longitude and latitude) after connected with location API according to request by users; the Web service uses an online portal developed in the PHP which is an open source general; the Web service sends and receives data with insert/delete, and the Web service performs the tasks and generates output in the JSON format [12]:

[{"gsmlatitude":"33.24567","gsmlongitude":"44.362478","datetime":"2017/12/22 17:17:26"}, {"gsmlatitude":"33.245621","gsmlongitude":"44.362425","datetime":"2017/12/22 17:22:12"}, {"gsmlatitude":"33.245621","gsmlongitude":"44.362425","datetime":"2017/12/22 17:28:36"}, {"gsmlatitude":"33.249792","gsmlongitude":"44.358406","datetime":"2017/12/22 17:33:19"},

**59**

**Figure 3.**

*Proposed tracking system.*

*Geo Location of Mobile Device*

17:38:55"}]

information [13].

**6. Tracking system**

*DOI: http://dx.doi.org/10.5772/intechopen.92154*

{"gsmlatitude":"33.249792","gsmlongitude":"44.358406","datetime":"2017/12/22

Representational State Transfer (REST) is a structural style for creating Web services and exploits the advances and conventions of the World Wide Web, the relationship between the mobile and remote server by volley technique method proposed by Google 2013. The plan utilizes POST and JSON configurations to move

In order to implement a mobile tracking system with a GSM/UMTS network of detection of mobile location for places visited through your phone, the mobile device tracker connects with the tower BTS and stores location information (cell id, LAC, MCC, MNC) continuously for each specific period (5 minutes) in

*Geo Location of Mobile Device DOI: http://dx.doi.org/10.5772/intechopen.92154*

{"gsmlatitude":"33.249792","gsmlongitude":"44.358406","datetime":"2017/12/22 17:38:55"}]

Representational State Transfer (REST) is a structural style for creating Web services and exploits the advances and conventions of the World Wide Web, the relationship between the mobile and remote server by volley technique method proposed by Google 2013. The plan utilizes POST and JSON configurations to move information [13].

### **6. Tracking system**

*Recent Trends in Communication Networks*

**4. Android platform**

*The size range of cell type [10].*

**Table 1.**

database) [11].

**5. Web service**

the JSON format [12]:

17:17:26"},

17:22:12"},

17:28:36"},

17:33:19"},

really establish a call. MS always knows the Cell-ID of the cell it is in. The size of a cell may range some meters; accuracy depends on cell size (illustrate in **Table 1**) [10].

**Cell type Cell dimension (meter)**

Nanocell 1–10 Picocell 10–100 Microcell 100–1000 Small macrocell 1000–3000 Large macrocell 3000–30,000

Android is the platform introduced in 2007 for devices such as smartphones or tablets developed by Google, which is a Linux-based operating system and an open source code designed for touch screen mobile device. The applications were developed in Java language, which allows the software to be freely modified using the Android Studio software development kit (SDK). The SDK contains a comprehensive set of software libraries supported by integrated development environment (IDE), the Android Studio (Android 7.0) to get the cell ID, LAC, MMC, MNC, IMEI, and SSN of an Android mobile, and the database (SQLite) used to store this cell ID, LAC, MMC, and MNC values into periodical processes that are running as background process by applying Android service; Google Maps get from Web service the latitude and longitude in the format of a Java Script Object Notation (JSON) file, the Android mobile support from both Google Maps and third-party developers (remotely connect to a MySQL

A Web service is the software designed to support communication between mobile application and remote server and location API over a network. The Web service designed to provide compute location information results in obtaining specific geographic regions (longitude and latitude) after connected with location API according to request by users; the Web service uses an online portal developed in the PHP which is an open source general; the Web service sends and receives data with insert/delete, and the Web service performs the tasks and generates output in

[{"gsmlatitude":"33.24567","gsmlongitude":"44.362478","datetime":"2017/12/22

{"gsmlatitude":"33.245621","gsmlongitude":"44.362425","datetime":"2017/12/22

{"gsmlatitude":"33.245621","gsmlongitude":"44.362425","datetime":"2017/12/22

{"gsmlatitude":"33.249792","gsmlongitude":"44.358406","datetime":"2017/12/22

**58**

In order to implement a mobile tracking system with a GSM/UMTS network of detection of mobile location for places visited through your phone, the mobile device tracker connects with the tower BTS and stores location information (cell id, LAC, MCC, MNC) continuously for each specific period (5 minutes) in

**Figure 3.** *Proposed tracking system.*

SQLite Database. All these processes run as background by applying Android service which is without a suspect by the mobile user. When mobile connected with internet can retrieve location information from SQLite Database of the mobile device, the location information transfer into the remote server during synchronizing between SQLite and MySQL. The server uses PHP and MySQL and can get all the necessary data to locate the phone. The PHP file will compute both latitude and longitude for location information that is stored in MySQL during which connections are created with location API to obtain the locations visited by the mobile device and the results are stored in MySQL. The data (latitude and longitude) is then transferred to the mobile device in the form of the JSON format and Google Maps is used that will plot the locations. **Figure 3** shows the tracking system.

In this section, we propose a tracking system algorithm to develop models of the relationship between the mobile application and the server site. The proposed algorithm can be implemented in six steps, which are described in Algorithm (1):

**Algorithm (1):** Description of the tracking system:

**Step 1:** The mobile device can read the location information (cell id, LAC, MCC, MNC) using cellular network (GSM/UMTS) every 5 minutes. The location information, IMEI, SSN, and current date&time were stored in the SQLite database every 5 minutes. Note IMEI, SSN, and current date&time can be obtained from the mobile device.

**Step 2:** Always have 100 records inside the SQLite database to maintain the storage space of the mobile device. In case of addition, the first field is deleted to guarantee nonexceeded 100 fields.

**Step 3:** Transfer location information, IMEI, SSN, and date&time from SQLite into the remote database MySQL using Volley Technologies and Web services, the server has received (IMEI, SSN, cell ID, LAC, MNC, MCC) via POST.

**Step 4:** The Web services provided communication between MySQL and the location API; the location information is then transferred into a location API for obtaining latitude and longitude of each record; the link location API uses URL= http://us1.unwiredlabs.com/process.php to obtain the latitude and longitude.

**Step 5:** The results store latitude and longitude received from the location API in the MySQL database and create a JSON file.

**Step 6:** Through the mobile application, the data location is queried from the external database MySQL and received in the form of the JSON file format; the results use a JSON parser to display the location on Google Maps.

The tracking system can be separated into two parts that are mobile application and server site.

#### • Mobile application

The Android mobile application obtains IMEI, SSN, and current location information (cell id, LAC, MNC, MCC) in the four parameters; the four parameters are considered the basic and latitude and longitude can be found.

These application processes are run in a background service using the Android service. This allows it to run operations without affecting your user so that it can continue to update current location information of the four parameters at specific intervals and periodically for a particular time to be designated by request service while device users move around towers of the mobile phone. After obtaining four parameters it stored in the SQLite database of the internal storage with the IMEI number and the SIM card serial number and the current date and time, this continues to store inside SQLite even if the mobile becomes the screen off and without the need to connect the mobile phone to the Internet, the **Figure 4** shows sequence diagram the mobile tracking.

**61**

**Table 2**.

• Server site

**Figure 4.**

JSON format.

**7. Results**

*Geo Location of Mobile Device*

*DOI: http://dx.doi.org/10.5772/intechopen.92154*

*A sequence diagram of mobile tracking using GSM/UMTS.*

The SQLite database can store a maximum of 100 records which does not affect the storage capacity of the mobile device with the increasing data stored; in case if the record number inside SQLite database exceeds 100 records, the application deletes the first record and adds the current record at the end of the table. After connecting to the Internet, the mobile device can synchronize data

The server side includes a scripting language to be embedded into a PHP source document and a MySQL that is uses the open source relational database management system. After transferring four parameters to MySQL, create a connection between database MySQL and location API site http://us1. unwiredlabs.com so as to retrieve latitude/longitude from four parameters in all records and the output is stored in MySQL database. All records in a table have a specific IMEI number, this send the data to the Android mobile application in

We have successfully implemented an Android application of a mobile tracking system by using a GSM/UMTS network; the application was run on December 21, 2017, for the distance from Baghdad to Samarra, the location information was recorded every 5 minutes, that can find the nearest position visited, the mobile was not connected with Internet. Some results were shown in **Figure 5**. The results we see after calculating latitude and longitude depending on the location information of the GSM/UMTS network are described in

between SQLite and MySQL using the JSON format as intermediate.

#### *Geo Location of Mobile Device DOI: http://dx.doi.org/10.5772/intechopen.92154*

*Recent Trends in Communication Networks*

shows the tracking system.

from the mobile device.

MNC, MCC) via POST.

and create a JSON file.

**Algorithm (1):** Description of the tracking system:

SQLite Database. All these processes run as background by applying Android service which is without a suspect by the mobile user. When mobile connected with internet can retrieve location information from SQLite Database of the mobile device, the location information transfer into the remote server during synchronizing between SQLite and MySQL. The server uses PHP and MySQL and can get all the necessary data to locate the phone. The PHP file will compute both latitude and longitude for location information that is stored in MySQL during which connections are created with location API to obtain the locations visited by the mobile device and the results are stored in MySQL. The data (latitude and longitude) is then transferred to the mobile device in the form of the JSON format and Google Maps is used that will plot the locations. **Figure 3**

In this section, we propose a tracking system algorithm to develop models of the relationship between the mobile application and the server site. The proposed algorithm can be implemented in six steps, which are described in Algorithm (1):

**Step 1:** The mobile device can read the location information (cell id, LAC, MCC, MNC) using cellular network (GSM/UMTS) every 5 minutes. The location information, IMEI, SSN, and current date&time were stored in the SQLite database every 5 minutes. Note IMEI, SSN, and current date&time can be obtained

**Step 2:** Always have 100 records inside the SQLite database to maintain the storage space of the mobile

**Step 3:** Transfer location information, IMEI, SSN, and date&time from SQLite into the remote database MySQL using Volley Technologies and Web services, the server has received (IMEI, SSN, cell ID, LAC,

**Step 4:** The Web services provided communication between MySQL and the location API; the location information is then transferred into a location API for obtaining latitude and longitude of each record; the link location API uses URL= http://us1.unwiredlabs.com/process.php to obtain the latitude and longitude. **Step 5:** The results store latitude and longitude received from the location API in the MySQL database

**Step 6:** Through the mobile application, the data location is queried from the external database MySQL and received in the form of the JSON file format; the results use a JSON parser to display the location on

device. In case of addition, the first field is deleted to guarantee nonexceeded 100 fields.

The tracking system can be separated into two parts that are mobile application

The Android mobile application obtains IMEI, SSN, and current location information (cell id, LAC, MNC, MCC) in the four parameters; the four param-

These application processes are run in a background service using the Android service. This allows it to run operations without affecting your user so that it can continue to update current location information of the four parameters at specific intervals and periodically for a particular time to be designated by request service while device users move around towers of the mobile phone. After obtaining four parameters it stored in the SQLite database of the internal storage with the IMEI number and the SIM card serial number and the current date and time, this continues to store inside SQLite even if the mobile becomes the screen off and without the need to connect the mobile phone to the Internet,

eters are considered the basic and latitude and longitude can be found.

the **Figure 4** shows sequence diagram the mobile tracking.

**60**

and server site.

Google Maps.

• Mobile application

**Figure 4.** *A sequence diagram of mobile tracking using GSM/UMTS.*

The SQLite database can store a maximum of 100 records which does not affect the storage capacity of the mobile device with the increasing data stored; in case if the record number inside SQLite database exceeds 100 records, the application deletes the first record and adds the current record at the end of the table. After connecting to the Internet, the mobile device can synchronize data between SQLite and MySQL using the JSON format as intermediate.

• Server site

The server side includes a scripting language to be embedded into a PHP source document and a MySQL that is uses the open source relational database management system. After transferring four parameters to MySQL, create a connection between database MySQL and location API site http://us1. unwiredlabs.com so as to retrieve latitude/longitude from four parameters in all records and the output is stored in MySQL database. All records in a table have a specific IMEI number, this send the data to the Android mobile application in JSON format.

#### **7. Results**

We have successfully implemented an Android application of a mobile tracking system by using a GSM/UMTS network; the application was run on December 21, 2017, for the distance from Baghdad to Samarra, the location information was recorded every 5 minutes, that can find the nearest position visited, the mobile was not connected with Internet. Some results were shown in **Figure 5**. The results we see after calculating latitude and longitude depending on the location information of the GSM/UMTS network are described in **Table 2**.

**Figure 5.**

*Display result in Google Maps: (a) when the first marker is clicked, data&time are displayed; (b) with middle marker, title is displayed; (c) with the last marker, the title marker data and time is displayed.*

The application updates a location information that can also cause heavy battery consumption; this can be lowered to achieve better battery efficiency. The location information updates every 5 minutes the interval at which the current location is updated. **Table 3** illustrates the different intervals that can affect the battery life. The work creates new opportunities to perform tracking on remote servers, using a mobile device only to capture the location information and display the output results. The Volley Technologies provided the good communication infrastructure to transfer a data to the remote server and vice versa. When is receiving 25 requests for transferring the data between the mobile device and the remote server, compare a sync task and volley technology, a sync discussion 13.957 milliseconds and the volley discussion 4.275 milliseconds. Some tracking applications depended on GPS; there exist situations where GPS is not available, and the solution is to combine the GPS measured values with the measured values from the GSM/UMTS. This work provides a service that automatically tells their users when they enter or leave a boundary of predefined points of interest such as application Tammini from Zain.

#### **8. Conclusion**

The application showed a low-cost tracking system using a GSM/UMTS network, which is suitable for the works all over the world with the combination of the Android mobile phone and Web services. The overhead is much lower compared to average battery consumption, and the application successfully tracks mobile across a single sensing. We demonstrated tracking using a cheap hardware with open source projects and showed mapping techniques with cell tower databases to take advantage of tracking a mobile device. Finally, we proposed an improvement in location accuracy by using GSM/UMTS tracking that could be implemented without connecting to API location, thus using external geographical information and achieving the best performance for mobile dynamic location with Kalman filters.

**63**

**id** 855 856 857 858 859 860 861 862 863 864 865 866 867 868 **Table 2.** *Computing latitude and longitude from basis parameters.*

418

05

7096

51317

359435058919189

418

05

7096

53415

359435058919189

418

05

7096

53415

359435058919189

418

05

7096

53415

359435058919189

418

05

7096

50555

359435058919189

418

05

14008

19820716

359435058919189

418

05

14008

19813445

359435058919189

418

05

14008

19807215

359435058919189

418

05

14008

19807215

359435058919189

418

05

14002

19946338

359435058919189

418

05

14003

19943755

359435058919189

418

05

14003

19949440

359435058919189

418

05

14003

19945609

359435058919189

418

05

14003

19945606

359435058919189

**MCC**

**MNC**

**LAC**

**Cell ID**

**IMEI**

**Sim serial** 8996405440003317062

8996405440003317062

8996405440003317062

8996405440003317062

8996405440003317062

8996405440003317062

8996405440003317062

8996405440003317062

8996405440003317062

8996405440003317062

8996405440003317062

8996405440003317062

8996405440003317062

8996405440003317062

**Date&time** 21/12/2017 6:12:11

21/12/2017 6:17:04

21/12/2017 6:22:47

21/12/2017 6:27:52

21/12/2017 6:32:37

21/12/2017 6:37:24

21/12/2017 6:42:22

21/12/2017 6:47:06

21/12/2017 6:52:41

21/12/2017 6:57:28

21/12/2017 7:02:37

21/12/2017 7:07:24

21/12/2017 7:12:11

21/12/2017 7:17:04

33.855946

44.242762

33.782224

44.259622

33.782224

44.259622

33.782224

44.259622

33.647154

44.237929

33.52829

44.240307

33.489079

44.226421

33.44942

44.26146

33.449417

44.261456

33.30084

44.323802

33.279606

44.349513

33.254439

44.358063

33.245144

44.362708

33.245665

**Latitude**

**Longitude**

*Geo Location of Mobile Device*

*DOI: http://dx.doi.org/10.5772/intechopen.92154*

44.362809


*Recent Trends in Communication Networks*

application Tammini from Zain.

**8. Conclusion**

**Figure 5.**

The application updates a location information that can also cause heavy battery consumption; this can be lowered to achieve better battery efficiency. The location information updates every 5 minutes the interval at which the current location is updated. **Table 3** illustrates the different intervals that can affect the battery life. The work creates new opportunities to perform tracking on remote servers, using a mobile device only to capture the location information and display the output results. The Volley Technologies provided the good communication infrastructure to transfer a data to the remote server and vice versa. When is receiving 25 requests for transferring the data between the mobile device and the remote server, compare a sync task and volley technology, a sync discussion 13.957 milliseconds and the volley discussion 4.275 milliseconds. Some tracking applications depended on GPS; there exist situations where GPS is not available, and the solution is to combine the GPS measured values with the measured values from the GSM/UMTS. This work provides a service that automatically tells their users when they enter or leave a boundary of predefined points of interest such as

*marker, title is displayed; (c) with the last marker, the title marker data and time is displayed.*

*Display result in Google Maps: (a) when the first marker is clicked, data&time are displayed; (b) with middle* 

The application showed a low-cost tracking system using a GSM/UMTS network, which is suitable for the works all over the world with the combination of the Android mobile phone and Web services. The overhead is much lower compared to average battery consumption, and the application successfully tracks mobile across a single sensing. We demonstrated tracking using a cheap hardware with open source projects and showed mapping techniques with cell tower databases to take advantage of tracking a mobile device. Finally, we proposed an improvement in location accuracy by using GSM/UMTS tracking that could be implemented without connecting to API location, thus using external geographical information and achieving the best performance for mobile dynamic location with Kalman

**62**

filters.

**Table 2.**

*Computing latitude and longitude from basis parameters.*


**Table 3.**

*Computing frequency update intervals.*

#### **Author details**

Bashar M. Nema1 \* and Ali Nafaa Jaafar2

1 College of Science, Mustansiriyah University, Baghdad, Iraq

2 Electrical Engineering Technical College, Middle Technical University, Baghdad, Iraq

\*Address all correspondence to: bashar\_sh77@uomustansiriyah.edu.iq

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**65**

*Geo Location of Mobile Device*

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[8] Andreas W, Shangbo W, Guido Bruck H, Peter J. Traffic congestion estimation service exploiting mobile assisted positioning schemes in GSM networks. Procedia Earth and Planetary

### **References**

*Recent Trends in Communication Networks*

**Time interval Details**

*Computing frequency update intervals.*

**Table 3.**

Every 5 seconds This provides heavy consumption of battery power

Every 30 minutes This provides better battery efficiency

Every 1 minutes This is the default setting, which provides a better battery power

**64**

Iraq

**Author details**

Bashar M. Nema1

\* and Ali Nafaa Jaafar2

provided the original work is properly cited.

1 College of Science, Mustansiriyah University, Baghdad, Iraq

\*Address all correspondence to: bashar\_sh77@uomustansiriyah.edu.iq

2 Electrical Engineering Technical College, Middle Technical University, Baghdad,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

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Section 3

Wireless Communication

**67**

Section 3
