From protocol specifications to flaws and attack scenarios: an automatic and formal algorithm

Abstract

Presents a new approach to the verification of authentication protocols. This approach is formal, fully automatic and does not necessitate any specification of any protocol property or invariant. It takes the protocol specification as the parameter and generates the set of flaws, if any, as well as the corresponding attack scenarios. This approach involves three steps. First, protocol roles are extracted from the protocol specification. Second, the intruder's abilities to perform communication and computation are generated from the protocol specification. In addition to the classical, known intruder computational abilities, such as encryption and decryption, we also consider those computations that result from different instrumentations of the protocol. The intruder's abilities are modeled as a deductive system. Third, the extracted roles as well as the deductive system are combined to perform the verification. The latter consists in checking whether the intruder can answer all the challenges uttered by a particular role. If that is the case, an attack scenario is automatically constructed. To exemplify the usefulness and efficiency of our approach, we illustrate it on the Woo and Lam (1994) authentication protocol.