CRYPTANALYSIS OF A TYPE OF FORWARD SECURE SIGNATURES AND MULTI-SIGNATURES

摘要

Sunitha and Amberker proposed a type of forward-secure signature and forward-secure multi-signature schemes like ElGamal signature scheme in ICDCIT2008. They claimed that their schemes satisfied forward security assuming discrete logarithm problem is hard. Since then, multiple papers based on these schemes have been published. In this paper, we analyse the security of their schemes and provide five algorithms to attack the security of these schemes. We make a conclusion that none of these schemes satisfies the forward security.