1. Mutual authentication and group key agreement for low-power mobile devices Authors: Emmanuel Bresson, Olivier Chevassut, Abdeilah Essiari, David Pointcheval Source: Computer communications 27, 2004

2. Group key agreement protocol Client U  Server  LLK Key generation algorithm  Group  Server  Setup algorithm sk Remove algorithm   Group  Server sk  Join algorithm

3. Adversary  Advarsary Client U  Server Message M  SK Known key attack  LLK Forward-secrecy

4. Key generation  Secret key=x Public key=y=g x

5. Setup algorithm

6. Remove algorithm

7. Join algorithm

8. Authentication

9. Security Result

10. Improvement  