verify security protocols. Many important security properties can be

modelled as observational equivalences in this calculus. An important

part of such an observational equivalence between two processes is to

show that the computational power of an intruder is the same for both

processes. In this talk we give a characterisation the computational

power of an intruder.

This is joint work with Aybkek Mukhamedov and Mark Ryan.

Robert Recorde Room

Department of Computer Science