Weakness in Jung et al.'s ID-Based Conference Key Distribution Scheme

Junghyun NAM  Seungjoo KIM  Dongho WON  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E89-A   No.1   pp.213-218
Publication Date: 2006/01/01
Online ISSN: 1745-1337
DOI: 10.1093/ietfec/e89-a.1.213
Print ISSN: 0916-8508
Type of Manuscript: Special Section LETTER (Special Section on Cryptography and Information Security)
Category: Protocol
conference key distribution,  implicit key authentication,  parallel session attack,  

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In 2000, Xu and Tilborg proposed an ID-based conference key distribution scheme which builds on earlier work of Harn and Yang in the 2-party setting. Recently, Jung et al. have discovered security flaws in the Xu-Tilborg scheme and proposed an improvement of this scheme to fix the security flaws. However, Jung et al.'s improvement introduces another security weakness. We demonstrate this by showing that the improved scheme is vulnerable to a parallel session attack mounted by two colluding adversaries. Further, we recommend changes to the scheme that address this vulnerability.