Quantum cryptography is a relatively new field (which began to be developed in 1984), which seems to be taking its last steps to become commercially available, thus becoming the first directly quantum technology to do so. The motivation behind it is not small, since it will allow coding a message in an absolutely secure and illegible way, due to the laws of quantum mechanics, and independently of the power of any computer, even a quantum one. In what seems like a not-too-distant future, engineers who understand and are able to work with such systems will be needed. Therefore, this Master’s Thesis aims to give an introduction to the current development of the field, from the physical concepts that underlie it, to the state of the art of the technology. The text is intended for people with a background in Electrical Engineering, and little or no knowledge of quantum mechanics. However, other readers with a background in engineering or physics will also be able to take advantage of it. After reading it, the reader will be able to have a good starting point in the field, from which to continue developing their work.
Quantum cryptography is a relatively new field (which began to be developed in 1984), which seems to be taking its last steps to become commercially available, thus becoming the first directly quantum technology to do so. The motivation behind it is not small, since it will allow coding a message in an absolutely secure and illegible way, due to the laws of quantum mechanics, and independently of the power of any computer, even a quantum one. In what seems like a not-too-distant future, engineers who understand and are able to work with such systems will be needed. Therefore, this Master’s Thesis aims to give an introduction to the current development of the field, from the physical concepts that underlie it, to the state of the art of the technology. The text is intended for people with a background in Electrical Engineering, and little or no knowledge of quantum mechanics. However, other readers with a background in engineering or physics will also be able to take advantage of it. After reading it, the reader will be able to have a good starting point in the field, from which to continue developing their work.
The real-world systems of quantum cryptography represent an advancement in the field of communication, wherein the advantages offered by quantum mechanics are used to minimize security threats which are handled with classical computers. This chapter starts with introducing some concepts to the reader about Quantum Cryptography, starting with an overview of classical Cryptography and its limitations in this new era of quantum computing technologies. Certain aspects of quantum mechanics like superposition, quantum entanglement, no-cloning theorem, and their applications for Quantum Key Distribution are also studied. This followed a thorough analysis of key protocols BB84 and E91 to unmask their strengths in securing superior security. Security threats associated with quantum-cryptographic systems and their corresponding provable level of security are considered to strengthen the notion of quantum cryptography as opposed to methods of classical cryptography. The corresponding characteristics of such quantum-cryptographic methods are also discussed for their application in proper targets. By the end of this chapter, we will attempt to explain the conception of some complications regarding quantum mechanics, and how they are now of use in modern practices of quantum cryptography and why such techniques are needed at all.
Several big companies already developed working prototypes of quantum computers, however they are not powerful enough to perform complicated calculations and are very massive, just like the first models of conventional computers in the twentieth century. However, the process of improvement is progressing fast. The growth of quantum computers might take another five or ten years, maybe less, and those machines will be able to help scientists to solve difficult problems. On the other hand, they will endanger some popular cryptographic protocols. \n \nCryptologists around the world are working on an encryption system that will allow people to stay confidential, even when very fast quantum computers will appear. This new type of encryption is differing from every known type of ciphering. It may give people absolute information security. In theory, this new method does not have any weaknesses. Unlike other encryption methods which are based on mathematical functions, the new encryption system is based on a Quantum Physics laws, the same laws which are the foundation of quantum computers. The name of this system is quantum cryptography. \n \nThe main purpose of this work was to research different types of the conventional cryptographic algorithms and the quantum cryptographic algorithms, and a possible future of cryptography.
Lack of understanding of the ideas of quantum physics leads to the fact that the very word "quantum" begins to be perceived as a synonym for something mysterious, incomprehensible, and even doubtful. The arising errors sometimes lead to inadequate media coverage of the development of quantum technologies, as the case with the ignorant reaction of the press in June 2016 to the statement of the Russian authorities about the prospects of quantum teleportation, which some media presented as teleportation from science fiction. Such misunderstandings can impede the formation of the necessary trust in quantum technologies on the part of the business community, politicians and the public. In part, the reason for this state of the art may be the insufficient attention of physicists themselves to the development of popular scientific and pedagogical discourse, which makes it possible to correctly introduce the ideas of quantum mechanics into the context of general culture. For decades, physicists have flaunted the kind of esotericism of quantum mechanics. Journalists love to quote the classics of quantum physics: “Those who are not shocked when they first come across quantum theory cannot possibly have understood it” (Niels Bohr); “I think I can safely say that nobody understands quantum mechanics” (Richard Feynman); “Quantum mechanics is absolutely meaningless” (Roger Penrose) [1]. Indeed, for many quantum-scale phenomena, no analogues have yet been found in the everyday world, and they are difficult to express in our everyday language. As a result, the introduction to quantum mechanics begins with a description of the mathematical formalism, which becomes an obstacle for the untrained listener and is not suitable for popularization. Moreover, such an approach creates problems for physicists themselves: many of them, studying the mathematical formalism of quantum mechanics and being convinced in practice of its effectiveness, do not ask the question of how the founders of this science were able to go in the opposite direction and, starting from experience, find the required formalism. As a result, important problematic and heuristic aspects of the development of science may drop off even professional physicists’ radar. In view of the above, an important task is to find effective explanatory techniques that allow one to talk about quantum phenomena without resorting to mathematical apparatus and without abuse of doubtful metaphors. This article attempts to find such an approach to explaining quantum cryptography. The choice in its favor is determined by the fact that it is one of the most mature quantum technologies of the second generation, which is already beginning to generate a demand for technical specialists to set up and maintain secure quantum communication lines. This activity requires a general understanding of the ideas of quantum mechanics underlying the technology, but at the same time, it does not require full knowledge of the mathematical apparatus that is used in research and development. In accordance with this, the task was set to outline the principle of quantum cryptography without resorting to such abstract concepts as the state space of a quantum system, its bases and the choice between them in quantum measurement. In a popular scientific sense, the advantage of quantum cryptography is a simplicity for understanding. Our experience shows that its main points can be explained to students in about half an hour without extraordinary mental effort. It is also enigmatical and fascinating, since, on the one hand, it is associated with spy codes, and on the other hand, it provides protection based on the laws of nature. Methodologically, the positive aspect of quantum cryptography is valuable. Many fundamental premises of quantum physics are negative: the impossibility of making any measurement without affecting the system, the Heisenberg uncertainty principle, the nocloning theorem. At the same time, quantum cryptography, on the contrary, allows an absolutely secure distribution of the encryption key.
Quantum Cryptography is a novel approach to make the information and network world more secure. Unlike classical cryptography, quantum cryptography ensures the security of communication because it is based on the laws of Quantum Mechanics; a branch of physics that deals with the fundamental behavior of matter and their energies to the levels of subatomic particles. These particles and their intrinsic properties such as photon polarization and entanglement allow us to develop an unbreakable system of cryptographic information. Conventionally, the security has been primarily concerned with the secured distribution of secret key carried over an insecure channel. However, in Quantum Cryptographic systems the transmission of secret key is done using aforementioned laws of nature through a secured quantum channel highly susceptible to intrusion detection. Consequently, the Quantum Key Distribution (QKD), in conjunction with protocols such as BB84 protocol has emerged as an ultimate modern secured communication system. This article concentrates on briefly reviewing quantum cryptography, some recent developments and reports of its vulnerabilities.
A significant topic of contemporary cryptography research and standardization is the development of public key crypto systems that resist attacks from quantum computers. Protocols and applications should start investigating the use of quantum-resistant key exchange and encryption to protect the confidentiality of current communications against future quantum computers utilizing post-quantum cryptography for a particular key exchange. Since they operate harder and need fewer steps compared to conventional computers, quantum algorithms are more secure and robust. Attackers who use quantum computers have powerful computing capabilities, and a quantum allows for simple cryptographic system breaking. Security algorithms that are quantum secure are resistant to attacks from conventional, as well as quantum computers. This work has surveyed, summarized, and analysed previous research to provide readers of this study an integrated understanding of quantum cryptography. It also discusses quantum attacks, which could be used in place of more conventional cryptography techniques, such as quantum key distribution, which takes advantage of quantum mechanics' properties to ensure secure exchanges of the secret keys, and various quantum algorithms. With quantum computation becoming a very real threat, this should motivate more people to show an early interest in the future of cryptography.
Quantum cryptography is a revolutionary field that applies the principles of quantum mechanics to provide secure communication channels. One of the most popular techniques in quantum cryptography is Quantum Key Distribution, which uses quantum states to deliver secure keys. The main advantage of quantum cryptography is that it offers protection against eavesdropping and tampering, which is not possible with classical encryption methods. This is because copying data in a quantum state is virtually impossible, and any attempt to intercept or manipulate the data will result in its complete alteration. As a result, any third-party interference can be detected quickly. Traditional cryptographic algorithms used in modern cryptography are vulnerable to attacks due to the evolution of quantum computers and mathematical advances in the decomposition of large integers. Therefore, the solution to address this vulnerability is to apply the principles of quantum physics to cryptography. The aim of the paper is to survey the current scientific achievements in the field of quantum cryptography and to present some challenging issues.