Theoretical Research On Quantum-Cryptography-Based Digital Signature

Digital signature as a branch of cryptography has extensive applications in the field of information security, including identity authentication, data integrity and reliability, non-tampering, non-repudiation and anonymity. Compared with the classical protocols, quantum protocols tend to have higher security. Therefore, the research of digital signature theory based on quantum technology has important significance for the development of quantum cryptography.According to the actual needs and security requirements of different types of quantum signature scheme, we mainly explored and studied the design and security analysis of quantum signature protocol and obtained some results. The main work is as follows:With respect to quantum multi-signature, we analyzed the security of a quantum multi-signature protocol based on controlled quantum teleportation. The protocol has been cited many times as a quantum signature scheme, however, a few security flaws exist in the protocol. We gave some detailed attack strategies from the participants attack and proved that the second signer can obtain the signature key shared between the first signer and the verifier by intercept-resend attack and entangle auxiliary particle attack, so as to forge the first signature about any message, even achieve total break. In addition, the original protocol is vulnerable to external attacks. To solve the above problems, we also proposed the improvement to the scheme with some possible strategies.With respect to quantum blind signature, according to the cryptanalysis of two quantum blind signature schemes and a quantum proxy blind signature scheme, we found a common problem that was the verifier could forge the signature under known message attack in such protocols. This thesis has respectively given the specific elaboration to the proposed attack strategy, and proved that this kind of problem is worth to pay much more attention to the relevant follow-up study. We further proposed that once a dispute occurred, an arbitrator should be introduced. At the same time, we also gave some suggestions on the problem of the blindness.With respect to quantum proxy signature, we analyzed the security of a quantum proxy signature scheme. The scheme combined with the characteristics of group signature and proxy signature and realized the function of proxy group signature scheme. In the scheme, the arbitrator Trent was semi honest, but we found that Trent will have the ability to carry out the signature forgery under the known message attack.With respect to arbitrated quantum signature, a new arbitrated quantum signature scheme based on the x-type entangled state was proposed, which mainly applied in electronic payment system. The x-type entangled state was used to quantum key distribution and quantum signature in this protocol. Contracted to the previous protocols, our scheme has higher efficiency. From the security analysis, we can see that the proposed scheme can resist the forgery of the verifier and the disavowal of the signer.