In this paper, we first present a formalized security model for dynamic group blind signatures and then we propose a new group blind signature scheme which has a round-optimal signing protocol and yet does not rely on random oracles which is to the best of our knowledge the first scheme with such properties. Most of the previous schemes in the literature require either lengthy (many-round) signing protocols and/or random oracles to prove their security. Our scheme also allows for concurrent joining and yields signatures of a constant-size. In addition, the new variant of the Camenisch-Lysyanskaya signature scheme which we introduce and use for the joining protocol is of interest in its own right and could be used either on its own to sign group elements or as a building block for other cryptographic constructions.
Category / Keywords: public-key cryptography/ Group Signatures, lind Signatures, Group Blind Signatures, Security Model Date: received 5 Jul 2011, last revised 19 Jul 2011, withdrawn 24 Jul 2011 Contact author: ghadafi at cs bris ac uk Available format(s): (-- withdrawn --) Note: Under update. Will be available shortly. Version: 20110724:090614 (All versions of this report) Discussion forum: Show discussion | Start new discussion