Cryptology ePrint Archive: Report 2004/104
Efficient and Provably Secure Trapdoor-free Group Signature Schemes from Bilinear Pairings
Lan Nguyen and Rei Safavi-Naini
Abstract: Group signature schemes are cryptographic systems that
provide revocable anonymity for signers. We propose a group
signature scheme with constant-size public key and signature
length that does not require trapdoor. So system parameters can be
shared by multiple groups belonging to different organizations.
The scheme is provably secure in the formal model recently
proposed by Bellare, Shi and Zhang (BSZ04), using random oracle
model, Decisional Bilinear Diffie-Hellman and Strong
Diffie-Hellman assumptions. We give a more efficient variant
scheme and prove its security in a formal model which is a
modification of BSZ04 model and has a weaker anonymity
requirement. Both schemes are very efficient and the sizes of
signatures are approximately one half and one third, respectively,
of the sizes of the well-known ACJT00 scheme. We will show that
the schemes can be used to construct a traceable signature scheme
and identity escrow schemes. They can also be
extended to provide membership revocation.
Category / Keywords: Group signatures, traceable signatures, identity escrow,identity escrow, privacy and anonymity.
Publication Info: An extended abstract appears in ASIACRYPT 2004
Date: received 4 May 2004, last revised 1 May 2005
Contact author: ldn01 at uow edu au
Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | PDF | BibTeX Citation
Note: This full version provides new signing and verifying algorithms that are secure against the attack in Eprint 2005/122 "Breaking and Repairing Trapdoor-free Group Signature Schemes from Asiacrypt 2004". The new algorithms are more efficient than the improvement proposed in Eprint 2005/122.
Version: 20050501:081915 (All versions of this report)
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