Comparing Methods for the Efficient Analysis of PEPA Models of Non-repudiation Protocols

In this paper we study the overhead introduced by secure functions in considering two models of non-repudiation protocols. The models are specified using the Markovian process algebra PEPA. The basic model suffers from the well known state space explosion problem when tackled using Markov chain analysis. Following previous study of performance modelling on security protocols, mean value analysis and fluid flow approximation based on ordinary differential equations (ODEs) have been chosen as efficient analysis techniques. Mean value analysis is an efficient exact method for deriving a limited set of metrics for large numbers of clients involved in the protocols. Fluid flow approximations can be adopted to solve the system with extremely large populations and potentially derive a wider range of metrics. The models are analyzed numerically and results derived from mean value analysis are compared with the ODE solution.