A New Forward-Secure Proxy Signature Scheme

Based on the shortcomings of WCF scheme, this paper proposed an improved forward-secure proxy signature scheme. The new scheme does not evolve the authorized keys, but the proxy signer's private key, making it have the forward security. Even if the proxy signer's signature key at a certain time segment is given away, the attacker could not get the proxy signer's signature key in the previous time segment. Under these assumptions of strong RSA problem, computational Diffie-Hellman problem being hard, and discrete logarithm problem being hard in a finite field, the scheme has favorable security.