Convertible Nominative Signatures

Abstract. A feasible solution to prevent potential misuse of signatures is to put some restrictions on their verification. Therefore S.J.Kim, S.J.Park and D.H.Won introduced the nominative signature, in which only the nominee can verify and prove the validity of given signatures, and proposed a nominative signature scheme (called KPW scheme). In this paper, we first show that KPW scheme is not nominative because the nominator can also verify and prove the validity of given signatures. Then we extend the concept of nominative signature to the convertible nominative signature which has an additional property that the nominee can convert given nominative signatures into universally verifiable signatures. We give a formal definition for it and propose a practical scheme that implements it. The proposed scheme is secure, in which its unforgeability is the same as that of the Schnorr’s signature scheme and its untransferability relies on the hardness of the Decision-Diffie-Hellman Prob...

• Type: Conference
• Year: 2004
• Where: ACISP
• Authors: Zhenjie Huang, Yumin Wang
• Keywords: ACISP 2004, KPW Scheme, Nominative Signatures, Security Privacy, Signature