Secure and Efficient Proxy Signature Scheme in the Standard Model

Existing proxy signature schemes are not proved to have complete security in the provable security model for proxy signature, whether the schemes are secure needs to be further studied. We show a generalized provable security model for proxy signature. Comparing with Boldyreva's security model, we introduce Schuldt's work to our security model. We propose a secure proxy signature scheme, which is based on Waters' signature scheme in the standard model. Comparing with other proxy signature schemes having a reduction to CDH assumption in the standard model, our scheme is more secure and efficient.