On Signatures of Knowledge

In a traditional signature scheme, a signature on a message m is issued under a public key PK, and can be interpreted as follows: "The owner of the public key PK and its corresponding secret key has signed message m." In this paper we consider schemes that allow one to issue signatures on behalf of any NP statement, that can be interpreted as follows: "A person in possession of a witness w to the statement that x L has signed message m." We refer to such schemes as signatures of knowledge. We formally define the notion of a signature of knowledge. We begin by extending the traditional definition of digital signature schemes, captured by Canetti's ideal signing functionality, to the case of signatures of knowledge. We then give an alternative definition in terms of games that also seems to capture the necessary properties one may expect from a signature of knowledge. We then gain additional confidence in our two definitions by proving them equivalent. We const...

• Type: Conference
• Year: 2006
• Where: CRYPTO
• Authors: Melissa Chase, Anna Lysyanskaya
• Keywords: CRYPTO 2006, Cryptology, Public Key Pk, Signature, Signature Schemes