Cryptology ePrint Archive: Report 2005/188
Group Signature where Group Manager, Members and Open Authority are Identity-Based
Victor K. Wei and Tsz Hon Yuen and Fangguo Zhang
Abstract: We present the first group signature scheme with provable security
and signature size $O(\lambda)$ bits where the group manager, the group
members, and the Open Authority (OA) are all identity-based. We use the security model of Bellare, Shi, and Zhang, except to add three identity managers for manager, members, and OA respectively, and we discard the Open Oracle. Our construction uses identity-based signatures summarized in Bellare, Namprempre, and Neven for manager, Boneh and Franklin's IBE for OA, and we extend Bellare et al.'s group signature construction by verifiably encrypt an image of the member public key, instead of the public key itself. The last innovation is crucial in our efficiency; otherwise, Camenisch and Damgard's verifiable encryption would have to be used resulting in lower efficiency.
Category / Keywords: public-key cryptography / group signatures
Publication Info: ACISP 2005
Date: received 21 Jun 2005
Contact author: thyuen4 at ie cuhk edu hk
Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | PDF | BibTeX Citation
Note: Full version of the paper in ACISP 2005.
Version: 20050622:215451 (All versions of this report)
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