Provably Secure Short Proxy Signature Scheme from Bilinear Maps

An enhanced formal model of security for proxy signature schemes is presented and a provably secure short proxy signature scheme is proposed from bilinear maps. The proposed proxy signature scheme is based on two short secure signature schemes. One is used for delegating the signing rights and computing the standard signature; the other is used for computing proxy signature. Finally, a security proof of the proposed proxy signature scheme is showed by reducing tightly the security of the proposed proxy signature scheme to the security of the two basic signature schemes. The proposed proxy signature scheme has the shortest ordinary signatures and proxy signatures. Moreover, the proxy signature generation needs no pairing operation and verification needs just two pairing operation.