A Strong Designated Verifier Signature Scheme with Secure Disavowability

Abstract

Designated verifier signature (DVS) is a cryptographic primitive, which allows a signer to convince a designated verifier of the validity of a signed statement and prevents the verifier from convincing any third party about the signature. As a variant of DVS, strong DVS (SDVS), which exhibits perfect non-transferability, does not accommodate secure disavow ability (or non-repudiation). It makes a SDVS more like a message authentication code rather than a digital signature. In this situation, the signer has to bear the responsibility of some "forged" signatures produced by the designated verifier. Therefore, it's interesting to construct a strong DVS scheme with secure disavow ability. In this paper, we address this problem with a novel construction of a SDVS scheme with secure disavow ability. The new scheme utilizes a chameleon hash function and supports the signer to have a complete control of his signature. Our scheme achieves unforgeability, non-transferability and secure disavow ability. Comparisons show that the new scheme outperforms the existing one in terms of computational efficiency and signature length.