Research On Technique Of Proxy Signature And Blind Signature

With internet becoming more and more popular,people increasingly want to deal with electronic matters in more simple and secure ways.Digital signature is one of the important content of modern cryptography,and is also made to judge the identity of users.Digital signature is a more secure and more effective method of proving the authenticity and validity of the document than traditional hand-written signature.In this thesis,we first introduce research status of digital signatures and the relating mathematic problems corresponding to the ordinary signature scheme,then propose several proxy signature and blind signature schemes by using several new techniques.And we also analyze the security and efficiency of our schemes,and study the delegation and anonymity techniques of our schemes.The main research works of the author are as follows:First,we construct two blind signature schemes based on the difficulty of solving discrete logarithm.By comparison with similar schemes,our schemes have advantages of short signature length and high efficiency.Second,to simplify the chosen course of signing key,we construct a proxy signature scheme based on XTR and extend it into a multi-proxy signature scheme.The proposed schemes are not only proven to be secure in random oracle model,but also have the following advantages:short length of signing key,simple parameters chosen,less computation amount..Third,in order to solve the problem of the contradiction between the authentication and the privacy,we construct a designated-verifier chameleon proxy signature scheme.Only the designated verifier can verify the validity of the signature which can efficiently prevent the forgery from the dishonest verifiers.We also prove the scheme is secure in the random oracle model,the difficulty of forging a signature is equivalent to solving Computational Diffie-Hellman Problem.Fourth,we propose a structured proxy multi-signature scheme based on fingerprint technique,signers obey some orders to sign,the generation of private key depends on the unique of the signer's fingerprint.Besides the ordinary validity verification of the signature,we add fingerprint verification to improve the security of our scheme.