An efficient ID-based partially blind signature scheme and application in electronic-cash payment system

IntroductionBlind signature is a new kind of digital signature with additional property that is, it allows a user to get a signature on message without leaking any information about message to Signatory authority.The notion of Blind signature is first introduced by Chaum [1,2].With the incorporated properties of blindness and Untraceability, it plays an important role in many e-commerce applications where user anonymity is the main concern such as e-payment system, e-wallet [3,4].However, experts feel that fully blinded signature have some disadvantages, for example, except the public information; bank could not access the malicious customer for double spent money [5][6][7][8].A kind of Blind Signature, partially blind signature allows a user to request the signatory authority on some pre-shared information such that signatory authority only sign the message but could not able to see to message's content except the preshared information.Abe et al [9] was the first to propose the idea of PBS scheme which tackles the issues of fully blinded signature.To design an efficient, secure and flexible electronic cash payment, PBS scheme play an exceptional role.