Abstract:

To overcome the shortcomings of the existing schemes such as strong hardness assumption,long signatures and high compution cost, a new transformation is proposed. It can convert any simulativepartitioned identitybased signature with existentially unforgeable security to a strongly unforgeable signature. And a concrete strongly unforgeable identitybased signature based on Paterson’s scheme is constructed in the standard model. Under computational DiffieHellman assumption, the proposed signature scheme is provably secure against strongly existential forgery under adaptive chosen message attacks. In addition, the new scheme has some advantages over the available schemes, such as short signatures, low computation cost and high security.

Key words: strongly unforgeable signature, identitybased signature, standard model, provable security