Improved proof for LWB designated verifier signature scheme
Kangsheng Chen · Journal of Zhejiang University(Engineering Science) · 2008
For a designated verifier signature scheme(i.e.,LWB scheme) which is shown to be not delegatable,because the construction of distinguisher is unreasonable,its unforgeability proof is not correct.To solve this problem,a distinguisher was reconstructed in the random oracle model,which was used to calculate the probability that a tuple is Diffie-Hellman tuple or that a tuple is random tuple by statistical test.LWB scheme was showed to be unforgeable under chosen message attack based on decisional Diffie-Hellman(DDH) assumption in the random oracle model.And the improved distinguisher and this proof guarantee LWB scheme's security.