A STUDY ON EFFICIENT GROUP-ORIENTED SIGNATURE SCHEMES FOR REALISTIC APPLICATION ENVIRONMENT

摘要

Rapid development of data processing systems has made digital signatures an essential application. A digital signature basically associates a signer with the message. Its important characteristics are easy verification, unforgeability and undeniability. However, conventional digital signature schemes generally consider only single signer situations; this is impractical, because the authorized signatory in the business world is generally composed of signatures of several people. Therefore, to enable co-signatories on a document, several group signature schemes are hereby proposed in this paper, including threshold group signature, anonymous ring signature, and group signature that incorporates ring signature technology. Since the aforementioned signature schemes are all based on Elliptic Curve Cryptosystem (ECC), they have short key size, low computation load, and little bandwidth requirement. Therefore, all the above schemes are considerably efficient. Finally, analyses are carried out to prove that the proposed schemes can withstand signature forgery attack and are signer undeniable, and thus meet the security requirements.