Further Analysis of ID-Based Authenticated Group Key Agreement Protocol from Bilinear Maps
K.-A. SHIM · IEICE Transactions on Fundamentals of Electronics Communications and Computer Sciences · 2007
Recently, Choi et al. proposed an ID-based authenticated group key agreement with bilinear maps. Subsequently, Zhang and Chen showed that the protocol does not provide authenticity as claimed by replaying transcripts of the past session. To prevent those replay attacks, they suggest adding a time parameter to the message being signed. However, despite of such a modification, we show that the protocol is still insecure against insider colluding attacks without replaying transcripts of the past session.