Research On Group Digital Signature

The hard problem of computation of mathematics is the basic of cryptology theory. Signature of knowledge is one of important primes of cryptology. Because of special digital signatures, digital signatures are used widely and deeply in practice. In this paper, the idea and characteristic, which were provided in special digital signatures, are summed up; the hard problem of mathematics and classical signature of knowledge are analyzed and studied in detail. The main results are the following:1. A new type signature of knowledge--a signature of knowledge of thediscrete logarithm of a blinded representation, which provides the verifier trusts the prover has the knowledge of the discrete logarithm when the knowledge is unknown, is proposed. The new signature of knowledge is necessary for the solution of the problem of member deletion in group signature;2. Construct an efficient and secure solution scheme of member deletion problem in group signature. The signature of knowledge of the discrete logarithm of a blinded representation, the idea of evolution of secret and the concept of bulletin are used in this scheme. And the schemeis relatively independent so it can be transplanted to anther group signature scheme to practice the member deletion.