Abstract: We propose a robust proactive threshold signature scheme, a multisignature scheme and a blind signature scheme which work in any Gap Diffie-Hellman (GDH) group (where the Computational Diffie-Hellman problem is hard but the Decisional Diffie-Hellman problem is easy). Our constructions are based on the recently proposed GDH signature scheme of Boneh, Lynn and Shacham. Due to the nice properties of GDH groups and of the base scheme, it turns out that most of our constructions are much simpler, more efficient and have more useful characteristics than similar existing constructions. We support all the proposed schemes with proofs under the appropriate computational assumptions, using the corresponding notions of security.
Ref: A preliminary version of this paper appeared in Public Key Cryptography 2003 Proceedings, Lecture Notes in Computer Science Vol. 2567, Y. Desmedt ed, Springer-Verlag, 2003. Full paper available below.
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