Comment on Lee J-s et al.'s identity-based designated verifer proxy signature scheme and its improvement

摘要

In a designated verifier proxy signature scheme, one can delegate his or her signing capability to another user in such a way that the latter can sign messages on behalf of the former, but the validity of the resulting signatures can only be verified by the designated verifier. Recently, Lee J-s et al. proposed a new ID-Based designated verifier proxy signature scheme. They didn't analysis the security of their scheme. We found out that anyone can generate a valid signature on any message m and mw he choose. To overcome this flaw in Lee J-s et al.'s scheme, we formalized the notion of designated verifier proxy signature scheme, provide a new ID-Based designated verifier proxy signature scheme. We also analyzed the proposed scheme.