A New Type of Designated Confirmer Signatures for a Group of Individuals

A new concept of society-oriented designated confirmer signatures (SDCS) is introduced in this paper. SDCS is well suited to applications where the capability of the signer and that of the confirmer are both expected to be shared among a group of individuals. The ways to share the signing capability and the confirming capability are different due to the distinct stabilities of the signer group and the confirmer group. Based on the techniques of threshold cryptography, a concrete SDCS scheme is proposed and its security is analyzed. Ordinary designated confirmer signatures and threshold designated confirmer signatures can be regarded as special cases of the proposed society-oriented designated confirmer signatures. Meanwhile, our scheme can be converted into an ordinary signature scheme or a designated verifier signature scheme.