A Coalgebra as an Intrusion Detection System

In this paper we construct a coalgebra for an intrusion detection system todescribe the behaviour of a packet stream together with selected actions in the case ofintrusions. We start with an extension of the notion of the many-typed signature to thegeneralised signature and we construct the category of packets as a basic structure of ourapproach. A defined endofunctor captures the expected behaviour of the packet stream. Theconstructed coalgebra enables the description of the behaviour of the packet streamtogether with the reaction to intrusions.