Optimistic fair exchange [Elektronische Ressource] / eingereicht von Matthias Schunter
259 Pages

Optimistic fair exchange [Elektronische Ressource] / eingereicht von Matthias Schunter

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Optimistic Fair ExchangeDissertation zur Erlangung des GradesDoktor der Ingenieurwissenschaften (Dr. Ing.)der Naturwissenschaftlich Technischen Fakultat¨ Ider Universitat¨ des SaarlandesEingereicht von Matthias SchunterSaarbrucken,¨ October 2000AbstractA fair exchange guarantees that a participant only reveals its items (such assignatures, payments, or data) if it receives the expected items in exchange.Efficient fair exchange requires a so called third party, which is assumed to becorrect. Optimistic fair exchange involves this third party only if needed, i.e.,if the participants cheat or disagree.In Part I, we prove lower bounds on the message and time complexity oftwo particular instances of fair exchange in varying models, namely contractsigning (fair exchange of two signatures under a contract) and certified mail(fair exchange of data for a receipt). We show that all given bounds are tightby describing provably time and message optimal protocols for all consideredmodels and instances.In Part II, we have a closer look at formalizing the security of fair exchange.We introduce a new formal notion of security (including secrecy) for reactivedistributed systems. We illustrate this new formalism by a specification of cer-tified mail as an alternative to the traditional specification given in Part I.In Part III, we describe protocols for generic and optimistic fair exchange ofarbitrary items.



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Published 01 January 2004
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Language English
Document size 2 MB