Cryptology ePrint Archive: Report 2003/259

Attack on Two ID-based Authenticated Group Key Agreement Schemes

Fangguo Zhang and Xiaofeng Chen

Abstract: Authenticated group key agreement problem is important in many modern collaborative and distributed applications. Recently, there are two ID-based authenticated group key agreement schemes have been proposed, one is Choi $et\ al.$'s \cite{CHL04} scheme, the other is Du $et\ al.$'s \cite{Du03} scheme. They are all constructed from bilinear pairings based on Burmester and Desmedt scheme \cite{BD94}. In this paper, we propose an impersonation attack on the two schemes. We show that any two malicious users can impersonate an entity to agree some session keys in a new group if these two malicious users have the previous authentication transcripts of this entity. So, the two ID-based authenticated group key agreement schemes can not provide the authenticity as claimed. We propose a proposal to repair these schemes.

Category / Keywords: Authenticated group key agreement,Bilinear pairings, ID-based cryptography, Attack

Date: received 17 Dec 2003, last revised 19 Dec 2003

Contact author: fangguo at uow edu au

Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | PDF | BibTeX Citation

Version: 20031220:163829 (All versions of this report)

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