**2.5 Review of commercial quantum secure telecommunication systems**

The world's first commercial quantum cryptography solution was *QPN Security Gateway (QPN-8505)* (QPN Security Gateway, 2011) proposed by *MagiQ Technologies (USA).* This system (fig. 5 a) is a cost-effective information security solution for governmental and financial organisations. It proposes VPN protection using QKD (up to 100 256-bit keys per second, up to 140 km) and integrated encryption. The QPN-8505 system uses BB84, 3DES (NIST, 1999) and AES (NIST, 2001) protocols.

The Swiss company *Id Quantique* (Cerberis, 2011) offers a systems called *Clavis2* (fig. 5 b) and *Cerberis*. Clavis2 uses a proprietary auto-compensating optical platform, which features outstanding stability and interference contrast, guaranteeing low quantum bit error rate. Secure key exchange becomes possible up to 100 km. This optical platform is well documented in scientific publications and has been extensively tested and characterized. Cerberis is a server with automatic creation and secret key exchange over a fibre channel (FC-1G, FC-2G and FC-4G). This system can transmit cryptographic keys up to 50 km and carries out 12 parallel cryptographic calculations. The latter substantially improves the system's performance. The Cerberis system uses AES (256-bits) for encryption and BB84 and SARG04 protocols for quantum key distribution. Main features:

• Future-proof security.

Quantum Secure Telecommunication Systems 227

simple "one-way" architecture, in which the photons travel from sender to receiver. This design has been rigorously proven as secure from most types of eavesdropping attack. Toshiba has pioneered active stabilisation technology that allows the system to distribute key material continuously, even in the most challenging operating conditions, without any user intervention. This avoids the need for recalibration of the system due to temperatureinduced changes in the fibre lengths. Initiation of the system is also managed automatically, allowing simple turn-key operation. It has been shown to work successfully in several network field trials. The system can be used for a wide range of cryptographic applications, e.g., encryption or authentication of sensitive documents, messages or transactions. A

a) b) c)

Another British company, *QinetiQ*, realised the world's first network using quantum cryptography—*Quantum Net (Qnet)* (Elliot et al., 2003; Hughes et al., 2002). The maximum length of telecommunication lines in this network is 120 km. Moreover, it is a very important fact that Qnet is the first QKD system using more than two servers. This system

In addition the world's leading scientists are actively taking part in the implementation of projects such as *SECOQC (Secure Communication based on Quantum Cryptography)* (SECOQC White Paper on Quantum Key Distribution and Cryptography, 2007), *EQCSPOT (European Quantum Cryptography and Single Photon Technologies)* (Alekseev & Korneyko, 2007) and

SECOQC is a project that aims to develop quantum cryptography network. The European Union decided in 2004 to invest € 11 million in the project as a way of circumventing espionage attempts by ECHELON (global intelligence gathering system, USA). This project combines people and organizations in Austria, Belgium, the United Kingdom, Canada, the Czech Republic, Denmark, France, Germany, Italy, Russia, Sweden and Switzerland. On

Following no-cloning theorem, QKD only can provide point-to-point (sometimes called "1:1") connection. So the number of links will increase *N N*( 1) / 2 − as *N* represents the number of nodes. If a node wants to participate into the QKD network, it will cause some issues like constructing quantum communication line. To overcome these issues, SECOQC was started. SECOQC network architecture (fig. 6) can by divided by two parts. Trusted private network and quantum network consisted with QBBs (Quantum Back Bone). Private network is conventional network with end-nodes and a QBB. QBB provides quantum

programming interface gives the user access to the key material.

Fig. 5. Some commercial quantum secure telecommunication systems.

has six servers integrated to the Internet.

*SwissQuantum* (Swissquantum, 2011).

October 8, 2008 SECOQC was launched in Vienna.


Fig. 4. Methods of quantum secure telecommunication systems construction.

*Toshiba Research Europe Ltd (Great Britain)* recently presented another QKD system named *Quantum Key Server* (QKS, 2011). This system (fig. 5 c) delivers digital keys for cryptographic applications on fibre optic based computer networks. Based on quantum cryptography it provides a failsafe method of distributing verifiably secret digital keys, with significant cost and key management advantages. The system provides world-leading performance. In particular, it allows key distribution over standard telecom fibre links exceeding 100 km in length and bit rates sufficient to generate 1 Megabit per second of key material over a distance of 50 km — sufficiently long for metropolitan coverage. Toshiba's system uses a

• Cost-effectiveness: one quantum key server can distribute keys to several encryptors.

**METHODS OF QUANTUM SECURE TELECOMMUNICATION SYSTEMS CONSTRUCTION**

**QSS** using single

qubits

**QUANTUM TECHNOLOGIES**

*Toshiba Research Europe Ltd (Great Britain)* recently presented another QKD system named *Quantum Key Server* (QKS, 2011). This system (fig. 5 c) delivers digital keys for cryptographic applications on fibre optic based computer networks. Based on quantum cryptography it provides a failsafe method of distributing verifiably secret digital keys, with significant cost and key management advantages. The system provides world-leading performance. In particular, it allows key distribution over standard telecom fibre links exceeding 100 km in length and bit rates sufficient to generate 1 Megabit per second of key material over a distance of 50 km — sufficiently long for metropolitan coverage. Toshiba's system uses a

Fig. 4. Methods of quantum secure telecommunication systems construction.

D-LEVEL QUANTUM SYSTEMS TRANSFER

*Entangled states protocols*

*for d-level quantum systems*

*QUANTUM SECRET SHARING*

**QSS** using

entangled states

*Ping-pong*

*protocol with qubits*

*Ping-pong*

*protocols with d-level quantum* 

*systems*

*QUANTUM STREAM CIPHER*

Yuen 2000 protocol

(Y-00, αη-scheme )

*QUANTUM SECURE DIRECT COMMUNICATION*

**QSDC** using single

**Ping-pong** protocol

qubits

**QSDC**

with block

transfer

PROPERTIES OF QUANTUM ENTANGLED STATES (QUANTUM CORRELATION)

• Scalability: encryptors can be added when network grows. • Versatility: encryptors for different protocols can be mixed.

> *QUANTUM KEY DISTRIBUTION*

> > **QKD** using

entangled states

*Ekert protocol (Е91)*

**QKD** using single

qubits and qudits

*QUANTUM DIGITAL SIGNATURE*

**QDS** using

entangled states

**QDS** using single

qubits and qudits

*ВВ84,* 

*Six-states protocol*

 *, 4+2 protocol,* 

*Goldenberg-Vaidman protocol,* 

*Koashi-Imoto protocol*

*В92, Decoy states protocols,* 

SINGLE QUBITS TRANSFER (NON-CLONING THEOREM)

*ВВ84* 

*protocol and*

 *Six-states*  *protocol for d-level quantum* 

*systems*

simple "one-way" architecture, in which the photons travel from sender to receiver. This design has been rigorously proven as secure from most types of eavesdropping attack. Toshiba has pioneered active stabilisation technology that allows the system to distribute key material continuously, even in the most challenging operating conditions, without any user intervention. This avoids the need for recalibration of the system due to temperatureinduced changes in the fibre lengths. Initiation of the system is also managed automatically, allowing simple turn-key operation. It has been shown to work successfully in several network field trials. The system can be used for a wide range of cryptographic applications, e.g., encryption or authentication of sensitive documents, messages or transactions. A programming interface gives the user access to the key material.

Fig. 5. Some commercial quantum secure telecommunication systems.

Another British company, *QinetiQ*, realised the world's first network using quantum cryptography—*Quantum Net (Qnet)* (Elliot et al., 2003; Hughes et al., 2002). The maximum length of telecommunication lines in this network is 120 km. Moreover, it is a very important fact that Qnet is the first QKD system using more than two servers. This system has six servers integrated to the Internet.

In addition the world's leading scientists are actively taking part in the implementation of projects such as *SECOQC (Secure Communication based on Quantum Cryptography)* (SECOQC White Paper on Quantum Key Distribution and Cryptography, 2007), *EQCSPOT (European Quantum Cryptography and Single Photon Technologies)* (Alekseev & Korneyko, 2007) and *SwissQuantum* (Swissquantum, 2011).

SECOQC is a project that aims to develop quantum cryptography network. The European Union decided in 2004 to invest € 11 million in the project as a way of circumventing espionage attempts by ECHELON (global intelligence gathering system, USA). This project combines people and organizations in Austria, Belgium, the United Kingdom, Canada, the Czech Republic, Denmark, France, Germany, Italy, Russia, Sweden and Switzerland. On October 8, 2008 SECOQC was launched in Vienna.

Following no-cloning theorem, QKD only can provide point-to-point (sometimes called "1:1") connection. So the number of links will increase *N N*( 1) / 2 − as *N* represents the number of nodes. If a node wants to participate into the QKD network, it will cause some issues like constructing quantum communication line. To overcome these issues, SECOQC was started. SECOQC network architecture (fig. 6) can by divided by two parts. Trusted private network and quantum network consisted with QBBs (Quantum Back Bone). Private network is conventional network with end-nodes and a QBB. QBB provides quantum

Quantum Secure Telecommunication Systems 229

The primary objective of EQCSPOT project is bringing quantum cryptography to the point of industrial application. Two secondary objectives exist to improve single photon technologies for wider applications in metrology, semiconductor characterisation, biosensing etc and to assess the practical use of future technologies for general quantum processors. The primary results will be in the tangible improvements in key distribution. The overall programme will be co-ordinated by British Defence Evaluation and Research Agency and the work will be divided into eight workparts with each workpart co-ordinated by one organisation. Three major workparts are dedicated to the development of the three main systems: NIR fibre, 1.3-1.55 µm fibre and free space key exchange. The other five are dedicated to networks, components and subsystems, software development, spin-off

One of the key specificities of the SwissQuantum project is to aim at long-term demonstration of QKD and its applications. Although this is not the first quantum network to be deployed, it wills the first one to operate for months with real traffic. In this sense, the

• *Key Management Layer.* This layer manages the quantum keys in key servers and provides secure key storage, as well as advanced functions (key transfer and routing). • *Application Layer.* In this layer, various cryptographic services use the keys distributed

There are many practical and theoretical research projects concerning the development of quantum technology in research institutes, laboratories and centres such as Institute for Quantum Optics and Quantum Information, Northwestern University, SmartQuantum, BBN Technologies of Cambridge, TREL, NEC, Mitsubishi Electric, ARS Seibersdorf Research

This chapter presents a classification and systematisation of modern quantum technology of information security. The characteristic of the basic directions of quantum cryptography from the point of view of the quantum technologies used is given. A qualitative analysis of the advantages and imperfections of concrete quantum protocols is made. Today the most developed direction of quantum secure telecommunication systems is QKD protocols. In research institutes, laboratories and centres, quantum cryptographic systems for secret key distribution for distant legitimate users are being developed. Most of the technologies used in these systems are patented in different countries (mainly in the U.S.A.). Such QKD systems can be combined with any classical cryptographic scheme, which provides information-theoretic security, and the entire cryptographic scheme will have informationtheoretic security also. QKD protocols can generally provide higher information security

SwissQuantum network presents a major impetus for the QKD technology.

• Quantum Layer. This layer performs Quantum Key Exchange.

transfer mode.

technologies and dissemination of results.

The SwissQuantum network consists of three layers:

to provide secure communications.

and Los Alamos National Laboratory.

level than appropriate classical schemes.

**3. Conclusion** 

assistant, and Bob's module consists of a fixed device such as a bank asynchrone

channel communication between QBBs. QBB is consisted with a number of QKD devices that are connected with other QKD devices in 1:1 connection. From this, SECOQC can provide easier registration of new end-node in QKD network, and quick recovery from threatening on quantum channel links.

Fig. 6. Brief network architecture of SECOQC.

We also note that during the project SECOQC the seven most important QKD systems have been developed or refined (Kollmitzer & Pivk, 2010). Among these QKD systems are *Clavis2*  and *Quantum Key Server* described above and also:


channel communication between QBBs. QBB is consisted with a number of QKD devices that are connected with other QKD devices in 1:1 connection. From this, SECOQC can provide easier registration of new end-node in QKD network, and quick recovery from

We also note that during the project SECOQC the seven most important QKD systems have been developed or refined (Kollmitzer & Pivk, 2010). Among these QKD systems are *Clavis2* 

1. *The coherent one-way system (time-coding)* designed by GAP-Universite de Geneve and idQuantique realizes the novel distributed-phase-reference coherent one-way

2. *The entanglement-based QKD system* developed by an Austrian–Swedish consortium. The system uses the unique quantum mechanical property of entanglement for transferring

3. *The free-space QKD system* developed by the group of H. Weinfurter from the University of Munich. It employs the BB84 protocol using polarization encoded attenuated laser pulses with photons of 850 nm wavelength. Decoy states are used to ensure key security even with faint pulses. The system is applicable to day and night operation using

4. *The low-cost QKD system* was developed by John Rarity's team of the University of Bristol. The system can be applied for secure banking including consumer protection. The design philosophy is based on a future hand-held electronic credit card using free-space optics. A method is proposed to protect these transactions using the shared secret stored in a personal hand-held transmitter. Thereby Alice's module is integrated within a small device such as a mobile telephone, or personal digital

threatening on quantum channel links.

Fig. 6. Brief network architecture of SECOQC.

protocol.

and *Quantum Key Server* described above and also:

the correlated measurements into a secret key.

excessive filtering in order to suppress background light.

assistant, and Bob's module consists of a fixed device such as a bank asynchrone transfer mode.

The primary objective of EQCSPOT project is bringing quantum cryptography to the point of industrial application. Two secondary objectives exist to improve single photon technologies for wider applications in metrology, semiconductor characterisation, biosensing etc and to assess the practical use of future technologies for general quantum processors. The primary results will be in the tangible improvements in key distribution. The overall programme will be co-ordinated by British Defence Evaluation and Research Agency and the work will be divided into eight workparts with each workpart co-ordinated by one organisation. Three major workparts are dedicated to the development of the three main systems: NIR fibre, 1.3-1.55 µm fibre and free space key exchange. The other five are dedicated to networks, components and subsystems, software development, spin-off technologies and dissemination of results.

One of the key specificities of the SwissQuantum project is to aim at long-term demonstration of QKD and its applications. Although this is not the first quantum network to be deployed, it wills the first one to operate for months with real traffic. In this sense, the SwissQuantum network presents a major impetus for the QKD technology.

The SwissQuantum network consists of three layers:


There are many practical and theoretical research projects concerning the development of quantum technology in research institutes, laboratories and centres such as Institute for Quantum Optics and Quantum Information, Northwestern University, SmartQuantum, BBN Technologies of Cambridge, TREL, NEC, Mitsubishi Electric, ARS Seibersdorf Research and Los Alamos National Laboratory.
