Delegatability of an ID-based designated verifier signature scheme
Yun Ling, Yiming Xiang, Xun Sun · 2008
In this paper we criticize the claimed security of an identity-based strong designated verifier signature (IBSDVS) scheme proposed recently based on bilinear pairings. In particular, we show that, contrary to the authors’ claim, this scheme is delegatable if the computational Diffie-Hellman problem in the underlying group is intractable. We also explain why the claimed proof fails, in the hope that similar mistake is not repeated in future research.