Cloud computing system based on data centers has recently attracted considerable attention. In that system, all data are communicated via a high speed optical network between a customer and data center or between data centers. There is a serious threat so called "Eavesdropper data center business", which means the eavesdropper can get all data from the transmission line and sell specific data selected by the protocol analyzer to malicious people who want to get the secret data. So we need to consider cyber attack against Layer-1 (physical layer). Quantum cryptography has been developed to protect such an attack. In order to apply such a new security technologies, the communication performance is very important as well as its security, because the data speed is more than several Gbit/sec. This research note III will discuss communication performances of quantum key distribution (QKD) and quantum enigma cipher, and explaines that QKD based on single photon signals cannot realize appropriate data speed, but quantum enigma cipher can.
Cloud computing system based on data centers has recently attracted considerable attention. In that system, all data are communicated via a high speed optical network between a customer and data center or between data centers. There is a serious threat so called "Eavesdropper data center business", which means the eavesdropper can get all data from the transmission line and sell specific data selected by the protocol analyzer to malicious people who want to get the secret data. So we need to consider cyber attack against Layer-1 (physical layer). Quantum cryptography has been developed to protect such an attack. In order to apply such a new security technologies, the communication performance is very important as well as its security, because the data speed is more than several Gbit/sec. This research note III will discuss communication performances of quantum key distribution (QKD) and quantum enigma cipher, and explaines that QKD based on single photon signals cannot realize appropriate data speed, but quantum enigma cipher can.
This research note suggests a new way to realize a high speed direct encryption based on quantum detection theory. The conventional cipher is designed by a mathematical algorithm and its security is evaluated by the complexity of the algorithm for cryptanalysis and ability of computers. This kind of cipher cannot exceed the Shannon limit of cryptography, and it can be decrypted with proba- bility one in principle by trying all the possible keys against the data length equal to the secret key length. A cipher with quantum effect in physical layer may exceed the Shannon limit of cryptography. The quantum stream cipher by α/η or Yuen-2000 protocol (Y-00) which operates at Gbit/sec is a typical example of such a cipher. That is, ciphertext of mathematical cipher with a secret key is masked by quantum noise of laser light when an eavesdropper observes optical signals as a ciphertext of the mathematical cipher, while the legitimate receiver does not suffer the quantum noise effect. As a result, the inherent difference of accuracy of ciphertext between eavesdropper and legitimate receiver arises. This is a necessary condition to exceed the Shannon limit of cryptography. In this note, we present a new method to generate an inherent difference of accuracy of the ciphertext, taking into account a fundamental properties of quantum detection schemes.
This research note suggests a new way to realize a high speed direct encryption based on quantum detection theory. The conventional cipher is designed by a mathematical algorithm and its security is evaluated by the complexity of the algorithm for cryptanalysis and ability of computers. This kind of cipher cannot exceed the Shannon limit of cryptography,and it can be decrypted with probability one in principle by trying all the possible keys against the data length equal to the secret key length. A cipher with quantum effect in physical layer may exceed the Shannon limit of cryptography. The quantum stream cipher by α/η or Yuen-2000 protocol (Y-00) which operates at Gbit/sec is a typical example of such a cipher. That is, ciphertext of mathematical cipher with a secret key is masked by quantum noise of laser light when an eavesdropper observes optical signals as a ciphertext of the mathematical cipher, while the legitimate receiver does not suffer the quantum noise effect. As a result, the inherent difference of accuracy of ciphertext between eavesdropper and legitimate receiver arises. This is a necessary condition to exceed the Shannon limit of cryptography. In this note, we present a new method to generate an inherent difference of accuracy of the ciphertext, taking into account a fundamental properties of quantum detection schemes.
This research note II introduces a way to understand a basic concept of the quantum enigma cipher. The conventional cipher is designed by a mathematical algorithm and its security is evaluated by the complexity of the algorithm in security analysis and ability of computers. This kind of cipher can be decrypted with probability one in principle by the Brute force attack in which an eavesdropper tries all the possible keys based on the correct ciphertext and some known plaintext. A cipher with quantum effects in physical layer may protect the system from the Brute force attack by means of the quantum no cloning theorem and randomizations based on quantum noise effect. The randomizations for the ciphertext which is the output from the mathematical encryption box is crucial to realize a quantum enigma cipher. Especially, by randomizations, it is necessary to make a substantial difference in accuracy of ciphertext in eavesdropper's observation and legitimate user's observation. The quantum illumination protocol can make a difference in error performance of the legitimate's receiver and the eavesdropper's receiver. This difference is due to differences in ability of the legitimate's receiver with entanglement and the eavesdropper's receiver without entanglement. It is shown in this note that the quantum illumination can be employed as an element of the most simple quantum enigma cipher.
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.
The security issue for the next generation optical network which realizes Cloud Computing System Service with data center" is urgent problem. In such a network, the encryption by physical layer which provide super security and small delay should be employed. It must provide, however, very high speed encryption because the basic link is operated at 2.5 Gbit/sec or 10 Gbit/sec. The quantum stream cipher by Yuen-2000 protocol (Y-00) is a completely new type random cipher so called Gauss-Yuen random cipher, which can break the Shannon limit for the symmetric key cipher. We develop such a cipher which has good balance of the security, speed and cost performance. In SPIE conference on quantum communication and quantum imaging V, we reported a demonstration of 2.5 Gbit/sec system for the commercial link and proposed how to improve it to 10 Gbit/sec. This paper reports a demonstration of the Y-00 cipher system which works at 10 Gbit/sec. A transmission test in a laboratory is tried to get the basic data on what parameters are important to operate in the real commercial networks. In addition, we give some theoretical results on the security. It is clarified that the necessary condition to break the Shannon limit requires indeed the quantum phenomenon, and that the full information theoretically secure system is available in the satellite link application.
Current communication systems predominantly operate using classical bits, with security mechanisms grounded in traditional cryptographic techniques. These conventional methods rely on the computational difficulty of discrete mathematical problems, which are expected to be vulnerable in the emerging quantum era. The advent of quantum computing poses a significant threat to existing cryptographic protocols, as quantum algorithms can potentially break schemes once considered computationally intractable. This scenario has accelerated interest in quantum cryptography, an advanced paradigm that leverages the fundamental laws of quantum mechanics to ensure secure data transmission. Quantum cryptography, and in particular Quantum Key Distribution (QKD), offers a robust alternative to classical key exchange methods. Unlike classical schemes, QKD’s security is rooted in the physical properties of quantum states, making it immune to computational advancements, including those offered by quantum computers. Among the various QKD protocols, the E91 protocol, based on quantum entanglement, demonstrates significant potential for enhancing communication security and resilience against cyber-attacks. This study investigates the role of quantum cryptography in safeguarding data transfer, with a specific focus on the E91 QKD protocol. It explores the operational principles, security advantages, and practical considerations of E91 in the context of evolving cybersecurity threats. By providing a detailed examination of E91’s implementation and performance, this research contributes novel insights into its feasibility as a cornerstone technology for building secure communication frameworks in the post-quantum era.