Proxy re-signature Scheme Based on Quadratic Residues
In 1998, Blaze, Bleumer, and Strauss (BBS) proposed proxy re-signatures, in which a semi trusted proxy acts as a translator between Alice and Bob. The proxy re-signature schemes can be applied in many applications. However, the existing proxy re-signature schemes were all based on Diffie-Hellman assumption. In this paper, we present a proxy re-signature scheme based on quadratic residues, which is Bidirectional. The scheme is safety under the random oracle model. At the same time, the definition of forward-secure proxy re-signature is given, then a corresponding scheme is presented which can maintain the former signature’s safety even if current cycle’s Signature key has been leaked.