A Provably Secure Trapdoor Hash Function Based on k-ECAA

The integration of trapdoor hash function and scheme of digital signature not only enhances the security of the signature scheme, but also reduces the online computation during the construction of signatures. Many schemes of trapdoor hash function have been proposed. However, many of them are not provably secure. This paper proposes a trapdoor hash function based on an extension of k-CAA assumption, i.e. k-ECAA. On the assumption of random oracle model and adaptively chosen message attack, a forgery of collision implies solution of k-ECAA instanc