Cryptology ePrint Archive: Report 2004/115

Provably-Secure and Communication-Efficient Scheme for Dynamic Group Key Exchange

Junghyun Nam, Sungduk Kim, Seungjoo Kim, and Dongho Won

Abstract: Group key agreement protocols are designed to solve the fundamental problem of securely establishing a session key among a group of parties communicating over a public channel. Although a number of protocols have been proposed to solve this problem over the years, they are not well suited for a high-delay wide area network; their communication overhead is significant in terms of the number of communication rounds or the number of exchanged messages, both of which are recognized as the dominant factors that slow down group key agreement over a networking environment with high communication latency. In this paper we present a communication-efficient group key agreement protocol and prove its security in the random oracle model under the factoring assumption. The proposed protocol provides perfect forward secrecy and requires only a constant number of communication rounds for any of group rekeying operations, while achieving optimal message complexity.

Category / Keywords: cryptographic protocols / group key agreement, authenticated key agreement, provable security, factoring

Date: received 17 May 2004

Contact author: jhnam at dosan skku ac kr

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Version: 20040517:124109 (All versions of this report)

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