Abstract If the security assessments are not trusted, especially in cases of very high data security requirements, physical methods must be used for key generation and distribution, data encryption, and integrity and authenticity procedures. This ensures the confidentiality, integrity, and authenticity of the data against computationally powerful adversaries and mathematical attack methods that are still unknown (unpublished) today. This chapter provides an introduction to these topics, briefly compares mathematical methods, and discusses the generation and distribution of cryptographic keys, as well as QKD (Quantum Key Distribution), RKD (Radio signal Key Distribution), and MKD (Memeory Key Distribution).
Abstract If the security assessments are not trusted, especially in cases of very high data security requirements, physical methods must be used for key generation and distribution, data encryption, and integrity and authenticity procedures. This ensures the confidentiality, integrity, and authenticity of the data against computationally powerful adversaries and mathematical attack methods that are still unknown (unpublished) today. This chapter provides an introduction to these topics, briefly compares mathematical methods, and discusses the generation and distribution of cryptographic keys, as well as QKD (Quantum Key Distribution), RKD (Radio signal Key Distribution), and MKD (Memeory Key Distribution).
Following its etymology, the term cryptography denotes the techniques used to ensure the confidentiality of information in its storage or transmission. Besides confidentiality, cryptography also encompasses other important functions such as authentication, signature, non-repudiation or secret sharing, to name just a few. The purpose of this section is to give a short introduction to classical cryptography, but only for areas that are relevant to quantum cryptography. For our purposes, we will only deal with confidentiality and authentication. The former is the most important function that quantum key distribution helps to achieve, while the latter is a requirement for quantum key distribution to work. Also, we will cover some topics on the security of classical cryptographic schemes so as to give some insight when comparing classical and quantum cryptography. The study of cryptography ranges from the analysis of cryptographic algorithms (or primitives ) to the design of a solution to a security problem. A cryptographic algorithm is a mathematical tool that provides a solution to a very specific problem and may be based on premises or on other primitives. A solution can be designed by combining primitives, and the requirements and functions of the primitives have to be combined properly. We will first review the confidentiality provided by ciphers that use the same key for both encryption and decryption, hence called secret-key ciphers . Then, we will discuss authentication techniques. Finally, we will show some aspects of public-key cryptography .
Abstract This book is aimed at anyone interested in high data security in telecommunications and data storage, especially procurers, experts, and decision-makers. Anyone involved in procurement in this field makes decisions about algorithms, technologies, and providers, and thus also about infrastructure and security. The generation and distribution of keys for data encryption play a central role in this. Because security assessments for mathematical methods are based on assumptions, physical methods are becoming interesting in the high-security sector. They promise to link security more closely to the laws of nature. This raises the key question: Which technology is suitable for which application scenario, and what assumptions, costs, and operational risks are involved? This book provides answers and, for the first time, compares QKD (quantum key distribution), RKD (radio signal key distribution), and MKD (memory key distribution) in a common, comprehensible criteria grid: technology-neutral and practical. Secret key rates, ranges/attenuation, robustness, costs/infrastructure, standardization, and risks (implementation, integration, post-processing, side channels) are deliberately evaluated not as a ranking, but as a decision-making aid. QKD derives its security from the laws of quantum physics, but secret key rates decrease with increasing attenuation. Key management systems connect short QKD distances over longer distances, but only at the cost of additional attack surfaces (“trusted nodes”). Its use for mobile applications fails due to a lack of technical maturity. Very high financial costs and high maintenance requirements for QKD solutions make them not very suitable. RKD utilizes the reciprocal physical properties of a radio link and scores points for its low technical complexity, excellent suitability for mobile applications (e.g., vehicles or drones), and very low costs. However, RKD falls far short of the key rates achieved by QKD solutions and is still limited to shorter distances. In addition, there is no established infrastructure for distributing key material to more than two partners. MKD takes a completely different approach: each party produces key material, stores it on a data carrier, and transports it physically to the other party. Because MKD can securely transfer 16 TB of key material in a single transport, only MKD has the potential to continuously provide a one-time pad (OTP) and thus provably 100% secure data encryption. The price is organizational responsibility: secure generation, storage, transport, and documented chain of custody. The book examines data security in telecommunications and data storage, discusses three new encryption methods specifically designed for QKD and RKD, and addresses the question of when “OTP-like” security is more practical than theoretical purity. The result of approximately one year of source-critical research and the comparison of literature, manufacturer specifications, and practical observations with systematic cross-checking and our own R&D activities, this book helps to justify architecture and procurement decisions, locate risks (side channels, misconfigurations, logistical vulnerabilities), and separate “security gains” from “new attack surfaces.”
Abstract This chapter and https://cryptography.study/phys/modes introduce four encryption methods/modes and the one-time pad, all of which are based on the XOR operation. The new methods/modes limit the required key length and are therefore particularly interesting for QKD and RKD. Because hash functions are already used in QKD and RKD, no additional mathematical methods are required for data encryption. One of these four methods/modes also generates a MAC for the security objectives of integrity and authenticity. Because these methods/modes are very simple in structure—they contain only the XOR function for data encryption (like the 100% secure one-time pad) and a hash/MAC algorithm—cryptanalysis is also easily possible.
Abstract Cryptography is a scientific method that is used to transmit secret information. In contrast, quantum cryptography depends on physical laws to encrypt information; when the quantum computer appeared, the classic encryption method becomes inefficient. The quantum method is commonly used to distribute keys, a process called as quantum key distribution (QKD). In this paper, we consider the efficiency of the quantum method compared to classical methods. Also, we discuss the security of QKD against several attacks and provide security analysis based on probabilistic models. Additionally, the paper explains how to encrypt random numbers into a sequence of photons using a QKD system for the distribution of a key. This research demonstrates the efficiency and security of QKD in sending and distributing keys between communication parties. Thus, both the sender and the receiver would be able to obtain a security key using the quantum method rather than classical methods.
Quantum cryptography provides secret communication, which offers various security factors like confidentiality, integrity, and authentication assurance based on the law of physics. The law of physics states that quantum computing can also be applied into the communication sector, which is particularly in the field of cryptography. Then quantum can significantly distribute the data securely by applying quantum key distribution (QKD), quantum key sharing, etc. In the classical cryptography, it is difficult to compute secret keys using security concepts like key exchange and authentication, etc., and it fails to provide adequate protection during data communication as it needs some effective computation in terms of security. The lack of security in the data communication can be overcome by using the concept of quantum computing. Generally, in quantum computing, elementary quantum systems like polarized photons are used to transmit digital information based on the principle of uncertainty as it gives rise to a significant phenomenon of effective security in terms of communication compared to existing concepts related to cryptography. In quantum computing, the detection ratio for identifying the data which are sent through a communication channel is more difficult as it uses qubits and photons to represent the data that are sent. Quantum channels are used to distribute the information between two users as it passes through the unprotected classical channels as it is unknown to anyone else. Assuming that Alice and Bob use a latent noise channel to send a key, reconciliation is the process of correcting errors between Alice and Bob’s version of the key. This is done by public discussion, which leaks some information about the secret key to an undercover. This chapter gives a discussion on QKD concepts as it helps to provide a secure communication, where the information is broadcasting through a quantum channel. Finally, the various existing quantum protocols are described in relation to some security measures based on QKD, and the standard QKD protocol of BB84 is discussed.
Abstract MKD (Memory Key Distribution) takes a completely different approach to QKD and RKD. With MKD, non-deterministic random number generators generate the cryptographic keys, and the keys are transmitted using highly secure hardware tokens (usually smart cards) or special portable storage media (usually SSDs) with highly secure access protection for the data. Only highly secure storage media can be used for a one-time pad and thus for cryptography that is entirely free of mathematics (except for XOR).