Research On Complex Digital Signature Schemes And Security Authentication

Digital signature as one of the main research contents in modern cryptography, is applied in wide fields such as information security, identity authentication, data integrality, undeniableness and anonymity, especially plays a great role in large network security and electronic business system. Digital Signature has become a necessary safety precaution in computer network, and been an important tool to assure data integrality and implement authentication.Complex signature is the result of combining typical signature schemes, and the conception is put forward with practical work condition. Complex signature plays an important role in information security and access control.In this dissertation, some complex signature systems are discussed in detail, including multi-signature, proxy-signature, group-signature, authenticated encryption signature and a secure authentication access control scheme based on digital signature. The main contributions are as follows:1. The security of common sequential multi-signature scheme based on discrete logarithm is analysed, and a new improved scheme is presented. And then Elgamal type sequential digital signature scheme based on RSA is presented, whose security are both based on large prime factorization and discrete logarithm,so as to is more secure and practical. Based on multi-signature scheme with distinguished signing authorities, a multi-signature scheme is introduced with undistinguished signing authorities.2. The security of proxy multi-signature is analyzed, a new proxy multi-signature scheme based on original Membo proxy multi-signature is presented. The strong proxy Multi-Signature scheme based on LKK is analyzed, and two types of forge attacks are proposed, by taking advantage of which, the attackers can forge a valid a proxy multi-signature. A new modified and secure strong proxy multi-signature scheme is presented to solve the corresponding security proplem. A group proxy multi-signature scheme based on threshold multi-proxy and proxy multi-signature is presented. In this scheme, a group of original signers can authorize a group of proxy signers, and only the cooperation of all signers in a proxy group can generate group-proxy multi-signature. A time stamped proxy signatures scheme with traceable receiver based on the Guillou-Quisquater digital signature has been proposed, whose security is based on large prime factorization, not only can commit the exact time when the proxy signers signed, but also can trace the figure of receiver.3. A irreciprocal group signature scheme is proposed, the scheme inherents in previously proposed schemes, and solves the anonymity problem. A scheme of group signature is proposed, which can prevent digital signatures from discretionarily spreading, the signers can be proved to own the signatures by zero-knowledge, not to show the signatures directly. A new threshold signature scheme is proposed, it can be validated simply, requires less computational cost, and has the virtues of anonymity, traceability, stability and so on. A new threshold signature scheme is presented, which is secure, validated efficiently, and as the same complexity of computing as the individual signature in many aspects.4. Based on discrete logarithms, a secure (t,n) threshold shared verification signature scheme is proposed in this paper, which integrates signature scheme with message recovery and the (t,n) threshold scheme. Two valid schemes are presented, to solve the problem that the recipient can not prove the honesty to any verifier if the signer denies the signatures in common authenticated encryption scheme. The first is a new convertible authenticated encryption scheme, the other is a new convertible authenticated encryption scheme with message linkages. And the two schemes is prior to similar schemes in computing characteristic. Finally, after analysing an publicly authenticated encryption scheme and pointing out its leak, an improved publicly authenticated encryption scheme is proposed.5. A secure authentication access control scheme based on digital signature is proposed, combining Harn digital signature scheme and the thought of zero-knowledge proof.