A new and efficient fail-stop signature scheme

The security of ordinary digital signature schemes relies on a computationa l assumption. Fail-stop signature schemes provide security for a sender aga inst a forger with unlimited computational power by enabling the sender to provide a proof of forgery if it occurs. In this paper we give an efficient fail-stop signature scheme that uses two hard problems, discrete logarithm and factorization, as the basis of a receiver's security. We show that the scheme has provable security against adaptively chosen message attack, and is the most efficient scheme with respect to the ratio of the message leng th to the signature length. The scheme provides an efficient solution to si gning messages up to 1881 bits.