Research Of Proxy Signature Scheme

Proxy signatures are signature schemes in which an original signer delegatesher signing capability to a proxy signer, and then the proxy signer creates a proxysignature on behalf of the original signer. When a receiver verifies a proxy signature, hecan verify both the signature itself and original signer's agreement together.In 1996, proxy signature and its efficient solution were introduced by Mambo etc.Since then proxy signature schemes have enjoyed a considerable amount of interestfrom the research institute. New proxy signature schemes have been proposed.Furthermore, various extensions of the basic proxy signature have been considered.These include threshold proxy signatures, nominative proxy signatures and proxymulti-signatures etc. Proxy signatures have been applied in many actual fields,particularly in distributed computing, e-vote, e-payment, grid computing, mobilecommunications etc, where delegation of rights is quite common.Based on the existent proxy signatures, our research focus on the forward-secureproxy schemes. At the same time, we solved the problems existed in e- vote and mobilecommunications.Main contributions of this paper are summarized as follows:1. Analyzed the securities of Shum-Wei scheme, P-L scheme and S-L scheme.2. Improved the W-C-F scheme, proposed a forward-secure proxy multi-signaturescheme, and a forward-secure proxy signature scheme based on elliptic curvecryptosystem.Aiming at the flaws in W-C-F scheme, an improved forward secure proxy signaturescheme was proposed. The new scheme proposed an evolution on proxy signer's key,under the strong RSA assumption and Diffie-Hellman problem, the new scheme wastruly forward secure.A forward-secure proxy multi-signature scheme was proposed on the basis of theforward-security and proxy multi-signature schemes. The new scheme satisfiessecurities of general proxy multi-signature schemes and forward-security.A forward-secure proxy signature scheme based on elliptic curve cryptosystem wasproposed. The new scheme is secure under the strong RSA assumption and the difficulty of elliptic curve discrete logarithm problem.3. Solved the problems existed in e-vote and mobile communications.Analyzed the security of D-Y-D scheme, and proposed a message protection proxysignature scheme with designated verifier. Under the assumption of the discretelogarithms' security, the scheme is secure and valid.A new desinated verifier proxy signature scheme with message recovery is proposedto reduces the commcication cost. Under the assumption of the discrete logarithms'security, the scheme is secure and valid.