Research On Identity-based Signatures

Digital signature, which can provide authentication, integrity and non-repudiation, is a key technique of information security. Compared with the Certificated Authority based (CA-based) cryptography, Identity-based (ID-based) signature can simplify the key management procedure from the view point of the efficiency and convenience.In this thesis we discuss ID-based signature schemes and ID-based threshold signature schemes. The main contributions are as follows:Discuss two classic ID-based signature schemes in detail. And compare their computation efficiency. Present the security proof for ID-based signature. Point out Some open problems in ID-based signature.Discuss the ID-based threshold signature and secret sharing which is used to construct the threshold cryptography. Analyze the security of the present ID-based threshold signature schemes, and then modify one of them to improve its security.Propose a new ID-based signature which can prevent the PKG from forging the signature.On basis of our new ID-based signature, two efficient ID-based threshold signature schemes are proposed, and their efficiency and security is analyzed.