A novel blind signature scheme and its variations based on DLP

Blind Signature is an addendum of Digital Signature.It is a two party protocol,in which a requester sends a message to a signer to get the signature without revealing the contents of the message to the signer. The signer puts the signature using his/her private keys and the generated signature can be verified by anyone using signer’s public keys.Blind signature has a major property called as untraceability or unlinkability i.e after the generation of the signature the signer cannot link the message-signature pair. This is known as blindness property. We have proposed blind signature scheme and its variation based on discrete logarithm problem(DLP),in which major emphasis is given on the untraceability property. We have cryptanalyzed Carmenisch et al.’s blind signature scheme and Lee et al.’s blind signature scheme and proposed an improvement over it. It is found that, the proposed scheme has less computational complexity and they can withstand active attacks. Blind signature has wide applications in real life scenarios, such as, e-cash, e-voting and e-commerece applications. ii