Introductory Chapter: Exploring Cryptography – Examining Its Fundamentals and Potential Applications

*Sudhakar Radhakrishnan and Sherine Jenny Rajan*

## **1. Introduction**

Fast communication between the digital and physical worlds is made possible by the Internet of Things (IoT).

This rapid growth has made everything in the world to get connected. Therefore, it will be essential to secure this growing amount of data while it is being transmitted. Cryptography is a crucial instrument used to protect this data [1].

The study of encrypting and decrypting data using mathematics is known as cryptography. With the use of cryptography, you can send or keep confidential data over unsecure networks, such as the Internet, such that only the intended receiver can read it. In our IoT-connected world, cryptography is utilized to encrypt all transferred data as well as to authenticate individuals, devices, and other gadgets. The study of data security is known as cryptography, and the science of deciphering and intercepting secure communication is known as cryptanalysis. Cryptography and Cryptanalysis together is said to be Cryptology. The history of cryptography is interesting and extraordinarily long and may be found in the book "The Code Book: The Secrets Behind Code breaking" by Simon Singh.

## **2. Fundamentals**

The goals of cryptography are confidentiality, integrity and availability. Information confidentiality is safeguarded by cryptography, which also makes sure data has not been altered and that the information originated from the intended source rather than an unauthorized sender [2].

Symmetric key and asymmetric key cryptography are the two forms of cryptography. Using the same secret key, the sender and the recipient encrypt and decode a message in symmetric cryptography [3]. Refer **Figure 1**. Most widely used AES belongs to symmetric key cryptography. Owing to its less complex mathematical procedures, symmetric key cryptography is typically quicker and more effective than asymmetric encryption. This makes it appropriate for real-time encryption of massive amounts of data, like that needed to secure network connections and data storage.

**Figure 2.** *Asymmetric encryption.*

A pair of keys, private and public key are used by Asymmetric key cryptography. A few of the algorithms are Diffie-Helman key exchange, RSA and others. The private key is kept private and is only known to its owner, but the public key is freely shared and can be circulated broadly [4]. To decrypt messages encrypted with a public key, only the corresponding private key is needed, and vice versa. Digital signatures, the cryptographic equivalent of handwritten signatures, are made possible via asymmetric cryptography [5]. A message or document can be signed by the sender using their private key, and the recipient can verify the authenticity of the signature using the sender's public key. The message's origin and integrity are guaranteed by this procedure. The public key can be provided by a trusted third party like certificate authority (CA). Asymmetric encryption is exemplified in **Figure 2**, where the recipient's public key is used to encrypt the plain text, and the recipient's private key is used to crack it. This provides confidentiality.

## **3. Challenges and research avenue**

The art of secure communication, cryptography, has several theoretical and practical difficulties [6]. Among the major challenges are


*Introductory Chapter: Exploring Cryptography – Examining Its Fundamentals and Potential… DOI: http://dx.doi.org/10.5772/intechopen.114073*


Numerous avenues for research into cryptography have been made possible by the difficulties in creating cryptographic algorithms. A great deal of recent effort has gone into creating post-quantum encryption that is resistant to quantum attacks, aiming to develop workable quantum-resistant cryptographic schemes. Current research examines methods such as homomorphic encryption to perform computations on encrypted data without exposing it. Research concentrating on standardization efforts to promote interoperability while maintaining security is in process. Further research on designing algorithms and implementations resistant to side channel attacks and optimizing cryptographic algorithms and protocols for better performance without compromising security is carried out.

## **4. Applications**

In many real-time applications, cryptography is essential for maintaining data confidentiality and privacy on a variety of digital platforms. Cryptography protects sensitive data in the domain of online banking and financial transactions by using encryption algorithms to prevent theft or unauthorized access to user passwords [12], credit card information, and transactional data. Cryptographic protocols like SSL/ TLS are used by secure communication channels, such email services and instant messaging applications, to encrypt data during transmission, protecting attachments and messages from tampering or eavesdropping. Cryptographic techniques are also used in the healthcare industry to secure electronic health records (EHRs), protecting patient privacy and adhering to legal requirements. Furthermore, encryption plays a major role in the developing field of block chain technology [13] by guaranteeing the immutability and integrity of distributed ledgers, allowing safe transactions. Many real time applications like Web Browsing [14], Messaging Apps [15], Bitcoin Transactions [13], Full Disk Encryption [16], Cloud Storage Encryption [17], Two-Factor authentication [12], Digital Signatures in Emails, Smart Home Devices & IoT devices [1], Military, Document security has increased the significance of encryption.

## **5. Conclusion**

Ultimately, cryptography ought to be viewed as the fundamental component of digital security, a vital tool for safeguarding personal information and ensuring secure communication in a range of settings. An overview of the basic ideas, challenges and applications of cryptographic systems has been given in this introductory chapter. Next chapters will explore the intricacies of encryption algorithms, key management, and real-world applications of cryptography in a variety of sectors as we continue our investigation of this fascinating field. Moreover, the ever evolving technological landscape poses a constant threat to cryptographic systems,

## *Biometrics and Cryptography*

necessitating constant innovation and adaptation to counter new attacks. By carefully examining its roots and applications, this study aims to shed light on how cryptography supports data integrity, confidentiality, and authenticity in our increasingly interconnected world.

## **Author details**

Sudhakar Radhakrishnan\* and Sherine Jenny Rajan Dr. Mahalingam College of Engineering and Technology, Coimbatore Dt, Tamil Nadu, India

\*Address all correspondence to: sudha\_radha2000@yahoo.co.in

© 2023 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.

*Introductory Chapter: Exploring Cryptography – Examining Its Fundamentals and Potential… DOI: http://dx.doi.org/10.5772/intechopen.114073*

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### *Biometrics and Cryptography*

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## **Chapter 2**
