Keeping Fairness Alive Design and formal verification of optimistic fair exchange protocols

The work in this thesis has been carried out at the centre for mathematics and computer science (CWI), under the auspices of the research school IPA (Institute for Programming research and Algorithmics). The research has been funded by the Dutch organisation for scientific research (NWO) in the context of the ACCOUNT project on accountability in electronic commerce protocols. Acknowledgements This thesis is the result of my research in the last four years at CWI. In the following, I mention some of those who helped me in doing this research. First comes Wan Fokkink, my supervisor and promotor. The liberty Wan gave me to follow my research interests and his constant encouragement were of great importance to me, both personally and professionally. A large part of the results that I report in the thesis has been produced jointly with Jan Cederquist. Jan has been the first critic of my work, besides being a very supportive friend. I would like to thank the members of the reading committee of my thesis, Bruno Crispo, Sandro Etalle, Joshua Guttman and Sjouke Mauw. Their feedback in many ways improved the quality of the thesis. I am also grateful to Jan Cederquist and Felix Freiling for participating in my promotion committee as opponent members. Among other colleagues, my promotor Jaco van de Pol and Michael Weber answered a lot of my questions and commented on my raw ideas. I very much appreciate their enthusiasm. I attended several herfstdagen and lentedagen schools organised by IPA, in which I was a member of the PhD council for the last three years. I also participated in two courses at the Vrije Universiteit, one on type theory taught by Freek Wiedijk and one on distributed algorithms taught by Wan Fokkink. It was very kind of them to let me participate in these courses. I sincerely thank Paul Klint, the current head of our team, for his support in facilitating my stay at CWI in the last few months. I co-wrote a few papers, some of which presented in this thesis. I enjoyed the time we spent together discussing " work " at CWI and elsewhere. A special gratitude goes to my parents, my brother Hesam and my sister Sanaz, with whom I shared my up and down times. I could not have led any kind of productive life in these four years without the huge amount of support that I …