Identity based group-oriented undeniable signature scheme

Group-oriented undeniable signature enables any subset of at least t members to represent a group to generate, confirm and disavow a signature. Several schemes were proposed and many of them are not secure. In this paper, we present an identity based (ID-based) group-oriented undeniable signature scheme which is secure in the random oracle model. To the best of authors' knowledge, our scheme is the first ID-based group-oriented undeniable signature scheme. A great merit of our scheme is that the signature confirmation and disavowal is completely non-interactive: the protocol of the verifier and confirmers is non-interactive and nothing is needed to exchange in between confirmers.