The Design And Analysis Of Quantum Cryptographic Protocols

Classical cryptography is widely used, but because it is generally based on the large integer factorization and discrete logarithm mathematical problems, therefore, it is computationally secure. With the development of the computer, its safety has been challenged; in particular, after the emergence of quantum mechanics and quantum algorithms, classical cryptography pose a serious threat. The quantum cryptography has unconditional security, because its unconditional security is guaranteed by quantum uncertainty principle, quantum no-cloning theorem, and the principle of quantum indistinguishability, in other words, it is better supe-riority and greater safety than classical cryptography.After decades of the development, not only quantum cryptography has become a new re-search field of the classical cryptography research, known as an important branch in the field of cryptography, and the different application background of various quantum cryptography protocols also spring up to stand out, but also has cause the scholars’ extensive concern and in-depth study. This paper is to study the quantum dialogue protocols, the controlled quan-tum secure direct Communication protocols, quantum signature protocol, and quantum key agreement protocol and so on, and we have obtained some preliminary research results, and the concrete content is as follows:A new controlled quantum secure direct communication (CQSDC) protocol is presented by using a four-particle cluster state as quantum channel and the physical characteristics of controlled quantum teleportation to implement the transmission and the control. In this protocol, the receiver can receive the secret message from the sender and recover the secret message under the permission of the controller. According to the security analysis, the com-munication is secure against both participant and outside attacks, so this CQSDC protocol is secure and feasible.A quantum dialogue protocol is proposed based on four-qubit entangled state, which is con-structed by an EPR pair and two different single qubits through three controlled-not gates. By using Bell measurements and the corresponding unitary operation, two users can ex-change their messages simultaneously and directly without sharing any secret keys before-hand. Security analysis shows that this protocol can resist the-intercept-resend attack and the entanglement-measure attack. The protocol is simple and feasible with current technique. A quantum proxy group signature protocol(QPGS) based on controlled teleportation is pre-sented by using the entangled five-qubit quantum state functions as quantum channel. The scheme uses the physical characteristics of quantum mechanics to implement delegation, signature and verification. The security of the scheme is guaranteed by the entanglemen-t correlations of the entangled five-qubit state, the secret keys based on the QKD and the one-time pad algorithm, all of which have been proven to be unconditionally secure and the signature anonymity.We present a three-party quantum key agreement protocol by using Greenberg-Horne-Zeilinger (GHZ) states and entanglement swapping. The proposed protocol realizes three parties suc-cessfully involve and agree on a key. Consequently, we show that the protocol is secure against the insider and the outsider attacks, such as the-intercept-resend attack,the-measure-resend attack and the-entangle-measure attack and so on, and has higher efficiency than the former work.