Strategy for Flaws Detection based on a Services-driven Model for Group Protocols

Group key agreement is important in many modern public and dedicated applications. Nevertheless, as they have to be secure, their design is not straightforward. As such, the modelling and the verification of such protocols are necessary in order to avoid eventual weaknesses. This paper investigates a strategy for flaws detection for group protocols properties. The strategy is based on both a services driven model for group protocols and constraint solving. Our strategy has been applied to several group protocols such as GDH.2 and the Asokan-Ginzboorg protocol. This permits to pinpoint new attacks on them. The result found for the case of GDH.2 with four participants can be generalized to n participants. Another general attack has also been found for the case of the A-GDH.2 protocol.