Security of the communications could be ensured using cryptography protocols. While asymmetrical protocols can be cracked using quantum computers, the symmetrical protocols stand against quantum attacks. However, the keys need to be exchanged in a secure way. A method is offered by the quantum key distribution (QKD) protocols. The QKD system should operate close to the fundamental quantum noise level. A possible attack is to steal some photons during the communication, but every change will result in some excess noise. This is why it is important to know the base noise level of the system, and every possible solutions need to be considered to reduce the noise of the system. To foster the research in this field, we started to develop a second generation QKD system over a 16 km long single mode, ordinary telecommunications fiber and focused on noise reduction.
Security of the communications could be ensured using cryptography protocols. While asymmetrical protocols can be cracked using quantum computers, the symmetrical protocols stand against quantum attacks. However, the keys need to be exchanged in a secure way. A method is offered by the quantum key distribution (QKD) protocols. The QKD system should operate close to the fundamental quantum noise level. A possible attack is to steal some photons during the communication, but every change will result in some excess noise. This is why it is important to know the base noise level of the system, and every possible solutions need to be considered to reduce the noise of the system. To foster the research in this field, we started to develop a second generation QKD system over a 16 km long single mode, ordinary telecommunications fiber and focused on noise reduction.
The exponential growth of global telecommunication networks has heightened the need for robust security frameworks to protect data transmission against evolving cyber threats.Traditional encryption techniques, such as RSA and AES, while effective, are increasingly vulnerable to advances in computational power and the impending threat posed by quantum computing.Quantum cryptography, specifically Quantum Key Distribution (QKD), presents a revolutionary approach to securing telecommunication systems by leveraging the fundamental principles of quantum mechanics.Unlike classical encryption methods, QKD guarantees data security through the use of quantum states that are inherently resistant to interception and eavesdropping due to the no-cloning theorem and Heisenberg's uncertainty principle.From a broader perspective, this paper explores the integration of quantum cryptographic protocols into existing telecommunication infrastructures, emphasizing their potential to safeguard data transmission in fiber-optic and satellite communication networks.It examines the architecture and operational mechanisms of QKD systems, detailing protocols such as BB84 and E91, and evaluates their effectiveness in countering both classical and quantum-enabled cyber-attacks.Additionally, the study delves into the challenges of large-scale deployment, including key distribution range limitations, hardware requirements, and the need for quantum repeaters to support long-distance secure communication.Narrowing the focus, case studies on the implementation of quantum cryptography in 5G networks and global telecommunication hubs are analysed, highlighting their role in enhancing network resilience and ensuring end-to-end encryption.The paper concludes with strategic recommendations for policy development, international standardization, and future research directions to facilitate the widespread adoption of quantum cryptography in the telecommunications sector.
As quantum computing threatens to compromise classical cryptographic systems, the need for future-proof, information-theoretically secure methods of communication has become critical. Quantum Key Distribution (QKD) leverages the fundamental principles of quantum mechanics to enable the secure generation and exchange of encryption keys, immune to computational attacks. This paper investigates the integration of QKD into telecom infrastructures to enable ultra-secure communication. We examine the performance of key QKD protocols, such as BB84 and E91, over fiber-optic and free-space channels, and simulate their deployment within realistic metropolitan network topologies. Results show that secure key rates of up to 10 kbps can be maintained over 50–80 km fiber links with Quantum Bit Error Rates (QBER) below 5%. The study also explores architecture models based on trusted relay nodes and WDM coexistence, highlighting practical deployment considerations. Our findings suggest that QKD is a viable enhancement for telecom security and a necessary foundation for long-term quantum-resilient communication systems.
In a society based on the continuous exchange of sensitive data and information, the importance of secure and trustful communications is essential. Quantum key distribution (QKD) makes it possible to share data in an unconditionally secure way exploiting the basic principles of Quantum Mechanics [1]. During the last 30 years, many QKD protocols have been developed and tested, achieving long distance transmission [2] and secret key rates up to hundreds of Mbits per second [3]. However, this technology is still far from a large-scale deployment in existing fiber networks and telecom infrastructures, due to multiple factors: low secret-key rate, limited distance between users, lack of applications, high costs and high requirements in terms of low noise fiber links.
As more aspects of modern society depend on digital communication, we increasingly rely on infrastructure that ensures the privacy and security of this communication. Classically, this has been provided by cryptographic protocols such as public-key encryption, in which secrets called keys are exchanged between different parties to enable secure communication. The rapid development of quantum algorithms which violate the assumptions of these protocols, however, poses a security challenge to modern cryptography. \n \nQuantum resources can also be used to strengthen cryptographic security, particularly the security of key exchange protocols. This approach, QKD, can be implemented by encoding in quantum systems such as single photons sent through free-space or a fiber. Fiber based QKD devices are already commercially available, but are fundamentally limited to distributing keys over a few hundred kilometers. To address this distance limitation, research QKD systems are being developed to exchange keys through free-space to satellites. This work considers practical challenges to building and testing both types of QKD devices. \n \nFirstly, we consider modeling and mission analysis for airborne demonstrations of QKD to stratospheric balloons and aircraft to simulate a satellite. Based on the mission parameters available for both platforms, we found aircraft platforms were more promising for testing prototype QKD satellite systems. We developed a mission planning tool to help design the flight geometries for testing the device. \n \nNext, we developed three new components for a QKD satellite prototype. The requirements for electro-optical devices in orbit are very different from lab environments, mandating new approaches to designing QKD devices. We developed a quad single photon detector package to meet the requirements for free-space links to low earth orbit. Moreover, we designed and built optical systems for analyzing the polarization of photons and an adaptive optics unit to increase the efficiency of collecting the encoded photons. All three devices were tested in conditions that simulated the time and loss of a satellite pass. \n \nFinally, we demonstrated a laser damage attack on a live commercial QKD system. Our attack injected additional optical power into the sender device to modify security-critical components. Specifically, our attack damaged the PIN diodes which monitor the encoded photon number, reducing their sensitivity or completely blinding them. Our damage could compromise the entire key, and was performed during system operation while raising no alarms. \n \nIn summary, this work shows the trade-offs of testing QKD payloads on different airborne platforms, develops components for a satellite QKD payload, and demonstrates a security vulnerability in a commercial QKD system that can fully compromise the key. These results help address practical challenges to building QKD devices, improving the security of modern cryptography.
Quantum key distribution (QKD) has been developed within the last decade that is provably secure against arbitrary computing power, and even against quantum computer attacks. Now there is a strong need of research to exploit this technology in the existing communication networks. In this paper we have presented various experimental results pertaining to QKD like Raw key rate and Quantum bit error rate (QBER). We found these results over 25 km single mode optical fiber. The experimental setup implemented the enhanced version of BB84 QKD protocol. Based upon the results obtained, we have presented a network design which can be implemented for the realization of large scale QKD networks. Furthermore, several new ideas are presented and discussed to integrate the QKD technique in the classical communication networks.
Quantum cryptography uses the quantum properties of individual photons to provide two or more users with means to communicate securely and efficiently. Specifically, quantum key distribution (QKD) focuses on the secure communication between two distant parties and guarantees the security of a transmitted message between them. Although QKD is the most mature application of quantum cryptography, applications of quantum mechanics in communication systems are not limited to QKD and other cryptographic protocols can be implemented as well. This thesis focuses on the implementation of quantum cryptographic systems over deployed fiber. A first QKD system was built and used to demonstrate the BB84 protocol over deployed fiber between the University of Calgary and SAIT. The system implemented a novel tool called quantum frames that allow for the quantum signals to be routed, for clock synchronization, and for channel stabilization in a network scenario. The same system was used to examine the scalability of the secret key generation rate in different steps of the process in order to detect potential bottlenecks for key generation rate of high speed systems. A second QKD system was developed to demonstrate the measurement-device independent QKD protocol. The system worked over deployed fiber between the University of Calgary, SAIT, and Foothills Hospital in the City of Calgary. The advantage of the measurement-device independent QKD protocol over previous QKD protocols is that it eliminates the possibility of side-channel attacks that target single photon detectors used in QKD systems. This demonstration also involved the first demonstration of a Bell state measurement over deployed fiber. Bell state measurements were further studied by using novel single photon detectors, which allowed demonstrating a highly efficient Bell measurement. Finally, a cryptographic protocol known as private queries was demonstrated between the University of Calgary and SAIT. Quantum private queries were demonstrated for the first time over deployed fiber by developing and implementing an error correction scheme to make the protocol noise and loss tolerant.