Research On Theory And Technology Of Society-Oriented Signature

With the rapid development of the Internet, electronic commerce makes important pattern of business affairs. It is the crux of the electronic commerce how to assure secure data transmission and authenticate the other party identity. That is to say, the crux of electronic commerce is the security. Because digital signature can solve repudiation, forgery, tamper and imitation, it becomes an important part of solving the security of electronic commerce.In this dissertation, we mainly study group signature, multi-signature, multi-signcryption , proxy signature and their application among the group-oriented digital signature, and give security analysis of some digital signature. In this research field, the research works of the author is as follows:1) We give security analysis of two improved group signature and show that they have the link-ability and the universal forgery, and give the corresponding attack to their schemes. At the same time, we analyze reason to produce these flaws. It has reference value to construct a secure group signature.2) To solve two intractable question of group signature: the revocation of group member and leak of private key, we give an efficient group signature: the group signature with forward security based on RSA problem and the difficulty of the solving discrete logarithm. Comparison with Dawn song scheme, the total computation of signing and verifying is only 8 exponentiations in our scheme and further less than 40 exponentiation in Song scheme.3) We give two multi-signature schemes based on RSA: one is the sequence multi -signature, the other is the broadcast multi-signature. Comparison with the others, they have less computation, less communication. Finally, we give a multi-signcryption model combining multi-signature with signcryption.4) We give security analysis to the nominative proxy signature for mobile communication, and show that the scheme don't satisfy non-repudiation, this is to say, the original signer can forge the signature of the proxy signer. At the same time, we create a proxy signature chain to prevent the malicious sever attack the mobile agent by the proxy signature.