The Design And Analysis Of Proxy Signature Schemes

In 1996, Mambo, Usuda and Okamoto proposed the concept of the proxy signature, in which a designated proxy signer can create valid signatures on messages on behalf of the orginal signer. To guarantee its security, they also pointed out that proxy signature schemes should satisfy the secure properties of undeniability, verifiability, unforgeability, indistinguishablity etc. Because the proxy signature has many important applications, such as E-commerce, E-government, E-cash, E-voting and Mobile Agent. Since it was proposed, home and overseas scholars have paid much attention to it.The main research results of the paper are stated in the following:1. Proxy signature scheme has the defect that it cannot solve the proxy revocation problem. Based on the idea of threshold, a new threshold proxy signature scheme is proposed in this paper, which key is consultated by all the participators; in cooperation with the signers, it can complete the eligibility to be reviewed without a trusted party, and check an effective and fast revocation of a proxy signer. It can help proxy signers to generate valid proxy signatures. At the same time, it can avoid legal signature by deception between each other.2. Curently, all of threshold proxy signature schemes are based on discrete logarithm problems. When the standard binary notation system was adopted to compute the integral multiple of an element of a group, Proxy signature based on the conic curve over Zn, by which time can be saved, so the scheme has advantages of speedy operation and easy realization. And while retaining the original signature of its merits, the scheme made comprehensively use of the difficulties in factorizing large and computing discrete logarithm, thereby increasing the performance of security and anti-deciphering.