Quantum key distribution (QKD) is the objects of close attention and rapid progress due to the fact that once first quantum computers are available – classical cryptography systems will become partially or completely insecure. The potential threat to today’s information security cannot be neglected, and efficient quantum computing algorithms already exist. Quantum cryptography brings a completely new level of security and is based on quantum physics principles, comparing with the classical systems that rely on hard mathematical problems. The aim of the article is to overview QKD and the most conspicuous and prominent QKD protocols, their workflow and security basement. The article covers 17 QKD protocols and each introduces novel ideas for further QKD system improvement.
Quantum key distribution (QKD) is the objects of close attention and rapid progress due to the fact that once first quantum computers are available – classical cryptography systems will become partially or completely insecure. The potential threat to today’s information security cannot be neglected, and efficient quantum computing algorithms already exist. Quantum cryptography brings a completely new level of security and is based on quantum physics principles, comparing with the classical systems that rely on hard mathematical problems. The aim of the article is to overview QKD and the most conspicuous and prominent QKD protocols, their workflow and security basement. The article covers 17 QKD protocols and each introduces novel ideas for further QKD system improvement.
Quantum technology, and especially quantum computing, is advancing rapidly. Our every-day secure communication infrastructure relies heavily on public key cryptography; unfortunately, many public key schemes are in fact insecure against quantum algorithms. Furthermore, adversaries who, today, capture information encrypted using classical key distribution systems, can wait and, as soon as quantum computers of sufficient power become available, they may decipher all previously captured information. While some new “post-quantum” public key systems are assumed to be secure against quantum computers, this is only an assumption and, even if the assumption remains valid, still results in systems that are less efficient for end-users than the more commonly used public key systems employed today. While the advent of quantum technology may seem detrimental to security, in fact, one may harness the power of quantum through quantum key distribution (QKD) for stronger security guarantees. Such QKD protocols allow two (or more) parties to establish a shared secret key, secure against an all-powerful adversary. Perhaps surprising is that QKD technology is already here both experimentally and commercially. This tutorial serves as an introduction to basic QKD along with QKD technology from a practical perspective. Quantum communication is a highly interdisciplinary field of research and one of the goals of this article is to introduce a larger set of researchers and practitioners to its study in the hopes of furthering its progress and eventual wide-scale adoption.
The security strength of key distribution of most conventional cryptography is relied on mathematical complexity and the irrational time needed to break the algorithm. But it will be ineffective if the secret key distribution procedure is weak. In 1994 Peter Shor proposed an algorithm that can factorize great integer number efficiently by using principle of quantum computer, this algorithm poses a threat to some of the conventional cryptography. Recently, Quantum Key Distribution (QKD) is drawing much attention of researcher as a solution of that problem of key distribution. Theoretically, QKD have been proven can be provide unconditionally secure communication based on quantum mechanics laws. In this article we survey the QKD protocols. Also, we present a little experiment of some QKD protocols that we discussed on this paper.
Data protection and information security have been the essence of communication in today's digital era. Authentication and secrecy of secure communication are achieved using key-based cryptographic primitives; the security of which significantly relies upon the underlying computationally complex mathematics. Moreover, these existing cryptographic primitives are considered to be non-deterministic on the basis of the existing computational capabilities. However, the considerable advancements in the development of quantum computers have significantly enhanced parallel computations; thereby, posing a great threat to these existing encryption primitives. Thus, in the future, the physical manifestation of a large successful quantum computer is likely to break all the existing public-key encryption algorithms in no time. This has led to a remarkable surge of interest in propelling quantum mechanics into existence; subsequently, leading cryptographers to research various viable domains to offer quantum-resistant secure communications. Resultantly, quantum cryptography/quantum key distribution has emerged as a futuristic replacement for classical cryptography as it offers unconditionally secure communication along with the inherent detection of any unintended user. Thus, keeping in view the significance of this relatively newer domain of cryptography, this research focuses on presenting a consolidated review of the various Quantum Key Distribution (QKD) protocols. A comparative analysis of the working mechanism of the prominent QKD protocols is presented along with an overview of the various emerging trends that have been proposed to optimize the implementational efficiency of the BB84 protocol.
The rapid advancement of quantum computing poses a significant threat to classical cryptographic systems that rely on the computational hardness of mathematical problems such as integer factorization and discrete logarithm problems. In this context, quantum cryptography has emerged as a promising paradigm for secure communication based on the fundamental principles of quantum mechanics rather than on computational assumptions. This paper presents a comprehensive review of quantum cryptography, with a particular focus on Quantum Key Distribution (QKD), the most mature application. The study discusses the theoretical foundations of quantum security, including superposition, entanglement, and the No-cloning theorem, which collectively enable eavesdropping detection and guarantee information-theoretic security. Furthermore, the review examines major QKD protocols, such as BB84 and E91, as well as their advanced variants designed to address practical vulnerabilities and enhance performance. Recent progress in real-world implementations, including fiber-optic networks, free-space communication, and satellite-based systems such as the Micius satellite, is also analyzed. In addition, the paper highlights critical challenges related to scalability, hardware limitations, and security loopholes arising from imperfect devices. Finally, emerging research directions, including hybrid cryptographic frameworks that integrate quantum and post-quantum approaches, are discussed to provide insights into the future of secure communication. This review aims to provide a structured, up-to-date understanding of quantum cryptography, bridging the gap between theoretical developments and practical implementations, and emphasizing its crucial role in shaping next-generation cybersecurity systems.
Quantum cryptography is an emerging field that ensures secure communication by leveraging principles of quantum mechanics. Unlike classical cryptography methods that rely on mathematical complexity, quantum cryptographic protocols, Quantum Key Distribution (QKD) protocols derive their security from the fundamental laws of physics. Among these, the BB84 protocol is widely recognized for enabling secure key exchange between communicating parties, with any eavesdropping attempts being inherently detectable. The invention of quantum computing poses a significant threat to classical encryption algorithms, and thereby necessitating both post-quantum cryptography and quantum-based approaches. This paper presents a comprehensive overview of quantum cryptography, emphasizing its theoretical principles foundations of quantum cryptography, emphasizing its advantages over traditional encryption methods, implementation challenges, and real-world application. It also outlines the limitations of quantum technology, e.g., hardware limitations and interference by noise, which restrict large-scale application. A detailed comparison between classical, quantum, and hybrid cryptographic approaches is presented to highlight the key advancement, including improved eavesdropping detection, enhanced key generation rates, and security through quantum entanglement. As quantum networks evolve rapidly, quantum cryptography is poised to become a cornerstone of nextgeneration ultra-secure communication systems.
The last decade, the evolution in quantum computing has been enormous and real and reliable quantum computers are being developed quickly. One of the consequences of the upcoming quantum era is to make key distribution protocols insecure, as most of them are based on discrete algorithm problems. On the other hand, quantum computing provides a powerful and prominent tool for the safe transmission of information and cryptographic schemes and many of them have already been proposed. In this work, we discuss about quantum cryptography and we present certain quantum key distribution protocols. We also discuss about ‘potential attacks that can be performed against the quantum cryptographic schemes which are based on quantum system’s imperfections and loopholes.