An Efficient and Secure Identity-Based Strong Designated Verifier Signature Scheme

A strong designated verifier signature scheme makes it possible for a signer to convince a designated verifier that she has signed a message in such a way that the designated verifier cannot transfer the signature to a third party, and no third party can even verify the validity of a designated verifier signature. In 2008, Zhang and Mao proposed a novel IDbased strong designated verifier signature scheme based on bilinear pairings by combining ID-based cryptosystem with the designated verifier signature. However, Kang et al. pointed out that Zhang-Mao scheme did not satisfy the strong designated verifier signature property and then proposed an efficient ID-based designated verifier signature scheme that is strong and unforgeable. Nevertheless, this paper demonstrates that Kang et al.’s scheme is still vulnerable to universal forgery attacks and then proposes an improved scheme that not only can overcome such forgery attacks but also can provide more efficiency.