This thesis contains an overview of development in cryptography and its uses in everyday life through different models of encryption, also there are examples from history of cryptography such as the Greek model, Cesar’s code and the mechanical cryptography device called Enigma. Using cryptography models such as symmetrical algorithms and asymmetrical algorithms it is shown what performances they have and also how they are used in program logic. The basic principles of quantum mechanics are introduced to describe fundamental physical properties on which quantum cryptography rests. The theoretical principals of quantum cryptography are shown from the aspect of achieving quantum communication, how one can establish that kind of communication with modern technology and why it is impossible to successfully eavesdrop someone from the aspect of quantum physics, or better said in the case of eavesdropping in a quantum communication channel the eavesdropper would be easily and quickly detected. The role of quantum key distribution in process of cryptography is explained and their task in the whole process is shown. In the methodical segment of this thesis preparations are shown which the professor of informatics can use as a helpful tool that will make understanding of cryptography easier for his students while the students work on seminars with different themes in cryptography and the cryptography realization through program code.
This thesis contains an overview of development in cryptography and its uses in everyday life through different models of encryption, also there are examples from history of cryptography such as the Greek model, Cesar’s code and the mechanical cryptography device called Enigma. Using cryptography models such as symmetrical algorithms and asymmetrical algorithms it is shown what performances they have and also how they are used in program logic. The basic principles of quantum mechanics are introduced to describe fundamental physical properties on which quantum cryptography rests. The theoretical principals of quantum cryptography are shown from the aspect of achieving quantum communication, how one can establish that kind of communication with modern technology and why it is impossible to successfully eavesdrop someone from the aspect of quantum physics, or better said in the case of eavesdropping in a quantum communication channel the eavesdropper would be easily and quickly detected. The role of quantum key distribution in process of cryptography is explained and their task in the whole process is shown. In the methodical segment of this thesis preparations are shown which the professor of informatics can use as a helpful tool that will make understanding of cryptography easier for his students while the students work on seminars with different themes in cryptography and the cryptography realization through program code.
Quantum cryptography is a relatively new area of computer security that deals with providing secure communication between the sender and recipient of information, using quantum-mechanical approach. It represents the vision of overcoming the classical methods of cryptography: asymmetric and symmetric algorithms, which have been used for several decades. It involves the establishment of a quantum channel between the participants, in which the transmission of information is realized using photons. The base of the quantum cryptography is formed by appropriate protocols that define the algorithm and method of exchanging and interpreting information. This type of security mechanisms has its undeniable theoretical advantages, but there are a number of problems related to the practical realization. The paper presents an overview of the general quantum principles and their characteristics underlying this form of cryptography and highlights the current advantages and disadvantages of quantum distribution security key.
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.
Quantum Cryptography is based on the use of subatomic particles (photons) and their intrinsic quantum properties (photon polarization) to develop an unbreakable system. It is not possible to measure the quantum state of any system without affecting the system. This property provides secure transmission of key between sender and receiver. Quantum Cryptography is a way to combine the relative ease and convenience of key exchange in public key cryptography with the ultimate security of a one-time pad. Quantum techniques for key distribution, the classically impossible task of distributing secret information over an insecure channel whose transmissions are subject to inspection by an eavesdropper, between parties who share no secret key initially. Quantum Cryptography uses the principles of Quantum Mechanics to implement a cryptographic system. The key problem which is solved by using quantum techniques is that of eavesdropping detection. The bits are represented as qubits, physically modeled by photons, and communicated over a quantum channel. The polarization states of photons represent 0's and 1's. Keyword: Asymmetric key, Cryptography, Protocols, Quantum, symmetric key
Due to the growing need for dana protection, especially nowadays when the Internet is
everywhere, systems are being developed that can enable this secrecy. Nowadays, the most
commonly used are classic cryptographic systems and cryptographic systems that have a public
key. Unfortunately, no cryptographic system can solve a known problem called „handle 22“.
Thanks to the great rise of technology, its development has led to a completely new type of
cryptography, quantum cryptography. With the help of quantum cryptography, we can more easily
detect if someone is eavesdropping on a communication channel. However, although quantum
cryptography is considered very secure, it is not always so, but if it is more secure than classical
why it is not used more often? The aim of this paper is to explain the basic possibilities of quantum
cryptography and its protocols, but also to point out its shortcomings.
The task of thesis is to describe the theory of quantum communications, which introduces the quantum mechanical properties of polarization and entanglement which do not have analogs in classical communications theory. At first, describes Moore's Law, and then the concept of quantum mechanics and its development throughout history. Describes the physical properties of waves and particles, explains electron spin and the postulates of quantum mechanics. Turns communication from classical to quantum and simple examples demonstrate how polarization and entanglement may be exploited to create noise-free channel and to improve channel utilization for distributed MAC protocols. It also describes the principle of quantum cryptography and describes quantum key distribution. Finally, describes how entanglement is used to enhance security and improve key distribution efficiency in symmetric-key cryptography systems used by operational quantum cryptographic networks.
The practical implementation of quantum information technologies requires, for the most part, highly advanced and currently experimental procedures. One exception is quantum cryptography, or quantum key distribution, which has been successfully demonstrated in many laboratories and has reached an advanced level of development. It will probably become the first commercial application of quantum information. In quantum key distribution, Alice and Bob exploit a quantum channel to create a secret shared key comprising a random string of binary digits. This key can then be used to protect a subsequent communication between them. The principal idea is that the secrecy of the key distribution is ensured by the laws of quantum physics. Proving security for practical communication systems is a challenging problem and requires techniques that are beyond the scope of this book. At a fundamental level, however, the ideas are simple and may readily be understood with the knowledge we have already acquired. Quantum cryptography is the latest idea in the long history of secure (and not so secure) communications and, if it is to develop, it will have to compete with existing technologies. For this reason we begin with a brief survey of the history and current state of the art in secure communications before turning to the possibilities offered by quantum communications. The history of cryptography is a long and fascinating one. As a consequence of the success or, more spectacularly, the failure of ciphers, wars have been fought, battles decided, kingdoms won, and heads lost. In the information age, ciphers and cryptosystems have become part of everyday life; we use them to protect our computers, to shop over the Internet, and to access our money via an ATM (automated teller machine). One of the oldest and simplest of all ciphers is the transposition or Caesarean cipher (attributed to Julius Caesar), in which the letters are shifted by a known (and secret) number of places in the alphabet. If the shift is 1, for example, then A is enciphered as B, B→C, · · ·, Y→Z, Z→A. A shift of five places leads us to make the replacements A→F, B→G, · · ·, Y→D, Z→E.