Design And Anaysis Of Quantum Signature Protocols

A digital signature, which is an important branch of cryptography, has been widely applied in in the field of information security. Digital signatures can achieve authentication, data integrity protection and non-repudiation services. With the rapid development of information toward digitization and networking, the problem of information security needs to be solved urgently. Information security in the traditional sense mainly relies on classical cryptography to provide security protection. However, the classical cryptography, based on the computational complexity of a variety of difficult math problems, is encountering an unprecedented impact with the continuous improvement of computing power. Quantum cryptography, which involves the quantum mechanics, can achieve unconditional security with respect to computational security of classical cryptography. Thus, it has received wide attention. Quantum signature, which contains quantum mechanics and digital signature, makes up for the security deficiency of classical digital signature and it is commonly used in electronic payment systems, such as electronic cash and electronic contracts.In this thesis, based on the existing the quantum signature, we have designed and improved a variety of quantum signature protocols according to the different needs of different application scenarios, such as quantum blind signature, quantum group signature and quantum signature with arbitrator. The details are as follows.In quantum blind signature:Firstly, we present the quantum signature protocol based on two-state vector formalism in the first time. By the two-state vector formalism, we can infer the state of the quantum system between two time measurements according to the results of the two measurements. Relative to the general description of the evolution of quantum states, this description is more perfect. We utilize the correlation of the quantum state between the two time measurements to design the quantum blind signature protocol, and the protocol has higher efficiency compared with the existing protocol. Secondly, we analyze the improved protocol based on our protocol proposed by Yang et al. and then we discover and point out that the improved protocol has security vulnerability, it cannot resist the participant attack. Thirdly, for the quantum sessional blind signature, from the perspective of information theory, we point out that information leakage problem is often ignored when designing a quantum signature protocol, especially the key information leakage will be a very important security issues. Then we proposed an improvement by increase the uncertainty to maintain the normal the entropy and to prevent the attacker from acquiring the key information.In quantum group signature:We make an analysis about a quantum group signature based on the teleportation and point out the common security issue of these kinds of protocols is the distribution of the entangled states. We introduce the counterfactual scheme that can safely distribute entangled states by two or three parties without the photon transmission on the quantum channel. As soon as the secure distribution of the entangled states, the security of the protocol is ensured.In quantum signature with arbitrator:We utilize the quantum one-way function to improve a quantum signature protocol with arbitrator. After the improvement, the protocol can resist the attacker to forge the legal signature. The application of quantum one-way function also can effectively avoid the insecurity of the model of quantum signature with arbitrator.