Tripartite Key Agreement Protocols and Insider Impersonation Attack
Hung‐Yu Chien, Ru-Yu Lin · 朝陽學報 · 2005
Even though several certificate-based tripartite key agreement protocols with pairings have been proposed, the insider impersonation attack was not noticed. This specific threat applies to those key agreement protocols where there are more than two communicating parties. This paper re-examines the previous protocols. We find that both Shim's scheme and the LHL scheme are not secure. The Shim scheme is weak in key-compromise impersonation attack, insider impersonation attack, and replay attack. The LHL tripartite key scheme is vulnerable to insider attack, outsider impersonation attack, and key-compromise impersonation attack. Furthemore, we propose two approaches to improve the security. Our schemes are more efficient than Al-Riyami-Paterson's tripartite key confirmation protocol, which is the most secure one among the referenced works.