Toward Secure Strong Designated Verifier Signature Scheme from Identity-Based System

A Designated Verifier Signature (DVS) scheme has the property of signer ambiguity, which can only convince a designated verifier of the signer's identity. It is not allowed for the designated verifier to transfer the conviction to any third party. A Strong Designated Verifier Signature (SDVS) scheme further requires the designated verifier's private key to perform the signature verification, so as to prevent anyone else from validating the signature. However, once the signer's private key is compromised, the security requirement of signer ambiguity will not be fulfilled. In this paper, we propose an identity-based SDVS scheme which can resist the key-compromise attack. Compared with related works, the proposed scheme also has lower computational costs. Additionally, the security requirement of unforgeability against Existential Forgery on adaptive Chosen-Message Attacks (EF-CMA) is formally proved in the random oracle model.