A Few Kinds Of Proxy Blind Signature Scheme

The rapid development of network and information technology has made the world smaller and smaller, and the speed of transmitting information has changed quicker and quicker. Network created by the IT space bring huge social benefits to the people, at the same time, the network and information security issues have become increasingly prominent. As a result, how to ensure the security of information systems has become an important research topic of now and even after quite a long period. The core content of the information system security is how to ensure the confidentiality, authentication and integrity of information in the system. The digital signature is one of the main means of certification, also one of the main contents of modern cryptography.Proxy blind signature, as an important part of digital signature, has always been one of the hot spots of cryptography research. Proxy blind signature is the combination of proxy signature and blind signature, has their both good natures. Although the security requirements of proxy blind signature are higher, but it is not difficult to achieve, and the application prospect is wider. Forward security is extensive researched in recent years, which ensure the validity of the forward signature after the secret key is compromised greatly ensure the security of the signature, and its security is quite high, and therefore of broad interest. The main results of this thesis are as follows:1. On the basis of the ElGamal signature system, a new proxy blind multi signature scheme is proposed. In the new scheme, a proxy signer can represent the signing power of many original signers to generate a valid signature. and the document signed by the signer is not visible. We analyze the correctness and the safety of the program including against internal attacks of the original signers, not can be linked, blindness, unforgeability, can be distinguished, agent authorized security and so on, the final analysis results show that the scheme is secure and practical. 2. We introduce forward security to the proxy blind signature, and so propose a forward secure proxy blind signature scheme. The program ensures that before the attacker cracked the secret key, the proxy signer use its proxy power making blind signatures are valid, they can not be affected, so the impact of this serious security incidents that the secret key is breaked is minimized with update the keys according to the period. This program has the excellent characteristics of the three forward secure, proxy signature and blind signature, and has considerable practical significance.