Verification of Security Protocols with Lists:

We present a novel, simple technique for proving secrecy properties for security protocols that manipulate lists of unbounded length, for an unbounded number of sessions.<br/> More specifically, our technique relies on the Horn clause approach used in the automatic verifier ProVerif: we show that if a protocol is proven secure by our technique with lists of length one, then it is secure for lists of unbounded length.<br/> Interestingly, this theorem relies on approximations made by our verification technique: in general, secrecy for lists of length one does not imply secrecy for lists of unbounded length.<br/> Our result can be used in particular to prove secrecy properties for group protocols with an unbounded number of participants and for some XML protocols (web services) with ProVerif.