Forward Secure( t,n) Threshold Proxy Signature Scheme with Designated Verifier
The signature scheme's security depends on the security of the secret key. Once the secret key is revealed,the adversary can forge all the previous generated signatures. And it is a great loss to the w hole signature system. According to the threshold proxy signature's key exposure problem,the forw ard security is integrated into it to propose a forw ard secure( t,n) threshold proxy signature scheme w ith designated verifier. Security analysis show s that the new scheme achieves a truly forw ard security. Even if all the signers' current secret keys are revealed also w on't affect the previous generated signatures' validity. The new scheme has a designated verifier,so the signature can only be verified by him,w hich can protect the original signer's privacy w ell. And the signature has the properties of message recovery,so it can be transmitted w ithout the plain message w hich reduces the communication costs of the signature transmission.