Verification of Secure Network Protocols in Uncertain Environments

Abstract

In this paper, we present a method for protocol checking and verification using discrete event control. By protocol checking and verification, we mean verifying that a protocol is logically correct, that it does not cause deadlocks, and that it has been defined to respond to uncontrollable events that may occur in a system implementing it. Our approach differs from those previously suggested in two key ways. We extend the elementary theory of discrete event control to allow us to model more complicated protocols, including protocols relying on arbitrary counting models. We then present a maximum probability method for analyzing a protocol's ability to react to a priori unspecified events. Unlike current protocol modeling, we use a pushdown automata for modeling protocols. This allows us to model protocols with greater fidelity. Our methods are illustrated using a simple two-level hierarchical protocol that defines the behavior of ad hoc wireless network nodes as they attempt to establish a secure connection. As wireless networks become more prevalent throughout the world, the off-line verification of protocols before they are implemented will help ensure that wireless network protocols are robust to security intrusions before they are deployed into the field. This will save time and money in the long run.