Research On Digital Multi-signature And Proxy Signature Algorithm

As one of the key technologies in the field of information security,digital signature can not only realize the user authentication,but also can protect the safety and integrity of the information,and ensure the signer's non-repudiation and traceability.Conventional digital signature algorithms,such as RSA and ECDSA,have been widely used in e-commerce,e-banking and e-government.Nowadays,the conventional digital signature method cannot meet the actual needs of the increasing development of information technology,so that some digital signature schemes with special functions and special properties have become a hot research issue in digital signature.In this thesis,we focus on the research of multi-signature system and proxy multi-signature scheme.The main contents are as follows:1.Aiming at the problem of the general sequential multi-signature scheme had slow signature generation speed,a new multi-signature scheme based on bilinear pairings on elliptic curves is proposed.The new scheme combines the advantages of both sequential and broadcast multi-signature schemes,and improves the signature speed of the sequential multi-signature scheme.Due to the use of bilinear pairings,large integer factorization problem(IFP),discrete logarithm problem(DLP)and computational Diffie-Hellman problem(CDHP),this scheme has higher security compared to the general one.This new digital signature scheme is generated by the trusted third party and the signer,so the signature is more credible.This multi-signature scheme is jointly generated by the trusted third party and the signer,so it is more credible.The efficiency analysis shows that this scheme has less computation than the original scheme.Our security analysis shows that this new scheme can resist the forgery attack and partial member collusion attack.2.To solve the security problem exist in Qi et al.and Wang et al.,a new proxy signature scheme based on discrete logarithm is proposed.By analyzing their proxy signature schemes,we found that their schemes are difficult to effectively resist the collusion attack and forgery attack.In our new scheme,both the user's private key and public key are generated by the mutual supervision and verification between the escrow center and the original signer,and it ensures the security of the keys.In addition,our security analysis shows that our scheme can resist the collusion attack and forgery attack.