Tutorial:Abstract.Wesurveyprinciplesofmodelcheckingtechniquesfortheautomaticanalysisofreactivesystems.TheuseofmodelcheckingisexemplifiedbyananalysisoftheNeedham-Schroederpublickeyprotocol.Wethenformallydefinetransitionsystems,temporallogic,!-automata,andtheirrelationship.Basicmodelchecki