A Certificateless Verifiable Strong Designated Verifier Signature Scheme

Certificateless strong designated verifier signature schemes have realized the merit of CL-PKC against the traditional strong designated verifier signatures. However, when the signer and the designated verifier disagree with the signature, existing schemes cannot distinguish the original signature from the signature transcript. In addition, errors or malicious actions introduced by the designated verifier may lead to the failure of signature verification. To solve these issues, we propose a certificateless verifiable strong designated verifier signature scheme. When disputes arise between the signer and the verifier, the scheme can effectively prevent the signer from denying the signature generated by the signer, as well as the designated verifier from denying valid signatures or invalid ones. Our scheme does not rely on bilinear pairings. The proposed scheme satisfies the requirements of verifiability, unforgeability, non-delegability, non-transferability and signer ambiguity. We also provide formal security proof in the random oracle model for the proposed scheme.