Partially Blind Signature Research Based On Bilinear Parings

Blind signature is a special kind of digital signature, in which the signer can’t learn the messages to be signed. Because of the blindness property of blind signature, the signer has no control over the messages to be signed, and the secret keys management becomes complex. Partially blind signature is an extension of the blind signature. It allows the signer explicitly embed a pre-agreed common infor-mation into a blind signature, which effectively solves the problems in blind signature. Bilinear paring has become a crucial tool for constructing the signatures in recent years. The bilinear paring-based digital signatures have the advantages of higher security and shorter key size.This dissertation lays emphasis on the bilinear paring-based partially blind signatures, and trys to solve the problem of "reduction attack". The main contri-butions are as follows:(1)Three partially blind signature schemes that can’t resist the tampering common information attacks are compared, and the principium and similarity of the attack methods are analyzed. Then the concept of "reduction attack" is proposed. The condition of making "reduction attack" is given and proved.(2)Two partially blind signature schemes proposed in classic literature are attacked using "reduction attack" method, which further verifies the condition of making "reduction attack".By destroying the conditions to make "reduction attack" a bilinear paring-based partially blind signature scheme is proposed, which not only meets the security requirements of partially blind signature, but also can resist "reduction attack".(3)A prototype system based on the scheme proposed in this dissertation is designed and realized in Visual Studio2010. The results of the experiment show that the scheme is correct and feasible,and can resist "reduction attack".