Another Efficient Proxy Signature Scheme in the Standard Model

As a concept of delegating signing rights for digital signatures, proxy signature is a well studied subject in cryptography. Most of proxy signature schemes are only proven to be secure in the random oracle. It is a challenge how to construct an efficient proxy signature in the standard model. To overcome this problem, in this paper, we proposed an efficient and provably secure proxy signature scheme in the standard model. And we show the security of the scheme is related to the hardness assumption of the k-BDHE problem. In terms of computation, no pairing operator is required in the proxy signature phase, and only two parings operators are needed in the verification phase. Thus our scheme is very efficient.