Proxy Signature Schemes Based on Signature of Zero-Knowledge

In a proxy signature scheme,the original signer delegates its signing power to the proxy singer. Many proxy signature schemes are proposed on basis of Schnorr signature scheme. However,some proxy schemes are insecure against the original's forgery attack. In this paper,we first combine signature of zero-knowledge with proxy signature and propose a secure strong proxy signature scheme with warrants and a secure strong multi-proxy signature scheme. These schemes do not only achieve strong distinguishability and non-repudiation properties but also achieve strong unforgeability property. They are still secure against the original signer's forgery attack. The proposed technique can also be applied to other ElGamal-like proxy signature schemes in which the original signer can impersonate the proxy signer and forge the proxy signature on any message.