Active Intruders with Caps
Résumé
We address the insecurity problem for cryptographic protocols, for an active intruder and a bounded number of sessions. By modeling each protocol step as a rigid Horn clause, and the intruder abilities as an equational theory over a convergent rewrite system, the problem of active intrusion is formulated as a Cap Unification problem. Cap Unification is an extension of Equational Unification: we look for a cap to be placed on a given set of terms, so that it unifies with a given term modulo the equational theory.