Modeling and analysis of guessing attacks in strand spaces

This paper presents an extension of strand spaces that can reason about various forms of guessing attacks on the authenticated protocol based on password. The sequences of attacker actions corresponding to the forms of guessing attacks are modeled composition strands. We present a systematic way of analyzing a protocol for guessing attacks within our framework. In particular, we argue whether randomly guessing values can be infeasible using the concept of threshold probability which is a measure of the system´s tolerance. We have illustrated these methods on GLNS protocol as an example.