Broadly speaking, cryptography is the problem of doing communication or computation involving two or more parties who may not trust one another. The best known cryptographic problem is the transmission of secret messages. Suppose wish to communicate in secret. For example, you may wish to give your credit card number to a merchant in exchange for goods, hopefully without any malevolent third party intercepting your credit card number. The way this is done is to use a cryptographic protocol. The most important distinction is between private key cryptosystems and public key cryptosystems.
Broadly speaking, cryptography is the problem of doing communication or computation involving two or more parties who may not trust one another. The best known cryptographic problem is the transmission of secret messages. Suppose wish to communicate in secret. For example, you may wish to give your credit card number to a merchant in exchange for goods, hopefully without any malevolent third party intercepting your credit card number. The way this is done is to use a cryptographic protocol. The most important distinction is between private key cryptosystems and public key cryptosystems.
Users of communication channels wish to have their transactions secured. Therefore, it is necessary to develop techniques which can ensure that eavesdroppers cannot intercept the messages transmitted. The technology concerned with the secure communication of data is termed as cryptography [1-3]. It is the art of hiding information in the form of a string of bits to an unauthorized party. To achieve this goal, in a classical cryptography system the message bits are combined with random bits of equal length called a key. The combined data is known as cryptogram. This technique is called encryption. A key can be public or private. The public key is to encode plaintext, while the private key is for decoding the previously encoded plaintext or cryptogram. The cryptogram is generally sent through the communication channel. Because of the randomness of the key the encoded message is completely random. Consequently, the message is untraceable to an eavesdropper. The safety of the transmission completely depends on the safety of the key. Therefore, the key should be kept secret by the users.
Quantum cryptography lies at the intersection of information theory and quantum mechanics. Cryptosystems come in two major classes depending on whether the key is shared in public or in secret. Public key cryptosystems are special in that they allow two people, who have not yet met, to communicate securely by looking-up encryption methods in a public directory. In quantum cryptography, the sender and receiver have two types of communication channels: a classical public channel and a quantum channel. The best application of cryptography is to allow a secure communication. In the near future, quantum cryptography may be used in top-secret applications in the military, for example, as the basis of communication links. The first protocol for quantum cryptography was proposed in 1984 by C. H. Bennett and G. Brassard. Some of the basic quantum cryptographic systems are: four-states protocol, two-states protocol, 4+2 protocol and multi-photon and multi-stage protocol.
This paper summarizes the current knowledge in the field of two-party cryptographic protocols devised from quantum systems. We introduce the reader to the notion of cryptographic protocols and describe a number of simple building blocks to achieve them. We also give pointers for the reader who is interested to the quantum implementation of these building blocks. 1 Introduction Since the 1970's the science of secret writing, cryptography, has changed substantially due to the introduction of "public key cryptosystems" [26, 41]. The many properties of certain instances of these systems have open the door to several new applications (consult [42, 25, 29, 44, 34, 28, 7, 30, 36, 32, 11, 19, 33] for instance, to mention just a few). The initial goal of cryptography, to provide secure communications, has evolved into a variety of tasks involving secret data. The scenario in which such tasks take place involves two participants (say Alice and Bob) who wish to perform some computation involving ...
Quantum computing and quantum cryptography are two areas of research that have the potential to transform modern computing and communication. Quantum computing promises to solve computational problems that are beyond the reach of classical computers, while quantum cryptography provides a way to secure communication channels that is immune to eavesdropping. Quantum cryptography is one of the emerging topics in the field of computer industry. This article focuses on quantum cryptography and how this technology makes a valuable contribution to an intensive defense strategy of completely secure key distribution. The scope of this article covers the weaknesses of modern digital cryptographic systems, the basic concepts of quantum cryptography, the practical implementations of this technology, and its limitations. , and finally the future direction that quantum cryptography is headed. We describe the result of an apparatus and protocol designed to perform quantum key distribution, whereby two users do not share any secret information (no private or public keys are known). previously known) initially exchanges a random quantum transmission consisting of veryweakly polarized light rays. In particular, readers can explore the following topics in depth: current cryptographic schemes (symmetric and asymmetric), the difference between quantum and classical computing, challenges of quantum computing, quantum algorithms (Shor and Grover), public key cryptographic schemes affected, symmetry affected schemes, impact on hash functions and post-quantum cryptography
Cryptography is used for the secure communication in which two parties are involved. The most popular cryptographic issue is the transmission of confidential messages. The privacy is maintained using the cryptographic protocol. The security of quantum cryptography relies more on physics including quantum mechanics and statistics rather than on solving mathematical problems. A well-known application of quantum cryptography is quantum key distribution (QKD) that is used to establish communication by generating cryptographic keys. Moreover, it is based on the Heisenberg uncertainty principle that ensures the security and prevents from eavesdropping. Basically, quantum cryptography with faint laser pulses, polarization coding, phase coding, and frequency coding have been discussed.
Quantum cryptography is known the most up-to-date in domain of realistic cryptography notably the menace of quantum cryptanalysis which threatens security firmness of public key cryptography. Quantum cryptography has a famous scheme known as Quantum Key Exchange (QKE), that administrates generation and distribution of a secured random key between legitimate channel users depicted as sender and receiver. Consequently, such key could be used as a key for one-time pad hybrid cryptosystems to encrypt and authenticate messages over a quantum channel. (QKE) is based on unifying quantum physics concepts and information theory with conventional cryptographic schemes that target to produce a short secret session key between any two legitimate parties. An important phase in key creation of BB84 protocol is Privacy Amplification phase where two interconnecting parties distill highly secret shared key from a larger body of shared key, which is only partially secret. The two legitimate parties publicly exchange information to create a compressed key free from biased bits known by an eavesdropper.