An Efficient Proxy Signature Scheme for Realizing Generalized Proxy Signing Policy

Proxy signature scheme is a method to delegate the signing authorization to one or more designated proxy signers. Only authorized proxy signers are able to generate a proxy signature on behalf of the original signer. Although many excellent studies on proxy signature schemes have been proposed, most of these schemes are mainly focused on dealing with (1, 1), (1, n), or (t, n) threshold proxy signature schemes. Therefore, in this paper, we are going to propose a novel proxy signature scheme with more generalized signing policy, in which any authorized proxy signing instance can cooperatively generate a valid proxy signature but the unauthorized proxy signing instance can not. Any verifier can not only verify the validity of the proxy signature but also confirm the identities of the actual proxy signers. Furthermore, our feature analysis shows that our scheme meets all the requirements of proxy signature.