An efficient forward-secure proxy-protected signature scheme based on the strong RSA assumption

A proxy signature scheme is an important extension of the digital signature scheme, nowadays, is an active research topic, which attracts more researchers´ attentions. As an ordinary digital signature scheme, a proxy signature is a vulnerable to the key exposure problem. In case, the secret signing key of the authorized user is be revealed or stolen. The aim of this paper is to put forth a proxy signature scheme, which has forward secrecy technique to mitigate the damage caused by the key exposure problem, which is proved secure. In this paper, the definition and security model of a forward-secure proxy signature scheme is formalized. Then, a generic forward-secure proxy-protected signature scheme is proposed based on the strong RSA assumption. By the reduction proof technique, the proposed scheme is proved secure against existential forgery adaptive chosen message attacks.