An efficient one-move Nominative Signature scheme

A signer in a Nominative Signature (NS) scheme can arbitrarily choose a nominee, then jointly generate a signature in such a way that the signature can only be verified with the nominee's consent. NS is particularly useful in user certification systems. Currently, the only secure NS scheme available requires multiround communications between the nominator and the nominee during signature generation. This implies that an NS-based user certification system requires a certification issuer to interact with a user using a complicated multiround protocol for certificate issuance. It remains an open problem to construct an efficient and non-interactive NS scheme. In this article, we solve this problem by proposing the first efficient one-move (i.e. non-interactive) NS scheme. In addition, we propose an enhanced security requirement called Strong Invisibility, and prove that our scheme satisfies this strong security requirement.