Security Analysis of Authenticated Key Exchange Protocol Based on the q-th Root Problem
K.-A. SHIM · IEICE Transactions on Fundamentals of Electronics Communications and Computer Sciences · 2007
Johnston and Gemmell proposed an authenticated key exchange protocol based on the difficulty of the q-th root problem. They showed that it is provably secure against man-in-the-middle attacks. In this paper we show that the protocol is insecure against an unknown key-share attack and does not achieve forward secrecy.