A Forward-Secure Ring Signature Scheme Based on Bilinear Pairing in Standard Model

Since the proposed ring signatures has the key exposure problem, a new forward-secure ring signature scheme based on bilinear pairings is proposed. Forward security of the scheme means that even if the secret key of current time period is compromised, some security remains. It is impossible to forge the signature relating to the past. Secret key is evolved with different period time while the public key is fixed in the life time. The scheme is proven to be secure against adaptive chosen message attack in the standard model.