## Section: Contracts and Grants with Industry

### The ANR SETIN RAVAJ

Participants : Nicolas Barré, Benoît Boyer, Thomas Genet, Thomas Jensen.

The RAVAJ ANR (http://www.irisa.fr/lande/genet/RAVAJ/ ) started on january 2007, for 3 years. RAVAJ means “Rewriting and Approximation for the Verification of Java Applications”. Thomas Genet is the coordinator of this project that concerns partners from LORIA (Nancy), LIFC (Besançon) and IRISA (Rennes). The goal of this project is to propose a general purpose verification technique based based on approximations and reachability analysis over term rewriting systems. To tackle this goal, the tree automata completion method has to be refined in two different ways. First, though the Timbuk tool is efficient enough to verify cryptographic protocols, it is not the case for more complex software systems. In that direction, we aim at using some results obtained in rewriting [66] to bring the efficiency of our tool closer to what has been obtained in the model-checking domain. Second, automation of approximation has to be enhanced. At present, the approximation automaton construction is guided by a set of approximation rules very close to the tree automata formalism and given by the user of the tool. On the one hand, we plan to replace approximation rules, which are difficult to define by a human, by approximation equations which are more natural. Approximation equations define equivalence classes of terms equal modulo the approximation as in [64] [83] [54] . On the other hand, we will automatically generate approximation equations from the property to be proved, using [42] [43] , and also provide an automatic approximation refinement methodology adapted to the equational approximation framework.