Cryptology ePrint Archive: Report 2009/291

Modeling Key Compromise Impersonation Attacks on Group Key Exchange Protocols

M. Choudary Gorantla and Colin Boyd and Juan Manuel González Nieto

Abstract: A key exchange protocol allows a set of parties to agree upon a secret session key over a public network. Two-party key exchange (2PKE) protocols have been rigorously analyzed under various models considering different adversarial actions. However, the analysis of group key exchange (GKE) protocols has not been as extensive as that of 2PKE protocols. Particularly, the security attribute of key compromise impersonation (KCI) resilience has so far been ignored for the case of GKE protocols. We first model the security of GKE protocols addressing KCI attacks by both outsider and insider adversaries. We then show that a few existing protocols are not secure even against outsider KCI attacks. The attacks on these protocols demonstrate the necessity of considering KCI resilience for GKE protocols. Finally, we give a new proof of security for an existing GKE protocol under the revised model assuming random oracles.

Category / Keywords: cryptographic protocols / Group Key Exchange, Key Compromise Impersonation, Insider Attacks

Publication Info: PKC 2009

Date: received 17 Jun 2009

Contact author: mc gorantla at isi qut edu au

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

Note: Typos corrected. Notations have been made consistent.

Version: 20090617:151126 (All versions of this report)

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