A revised enhanced short signature scheme with hybrid problems

Knapsack Diffie-Hellman problem with bilinear parings(KDH), proposed by Han et al, has been proved as hard as Subset Sum problem. Enhanced short signature scheme with hybrid problems is a signature scheme proposed by Su based on KDH problem. In this paper, we present a message attack that the adversary can easily forged a signature by capturing only one message and its signature. Then, we present a revised signature scheme against this kind of attack. Finally, we discuss the hardness between problem DLP, k-CAA´ and k-wCDHP.