A Game Theoretic Model and Tree Analysis Method for Fair Exchange Protocols

Exchange protocols are an important theoretic basis to make secure electronic commerce and electronic business transactions possible, in which the fairness is a crucial property. To ensure and verify the property, a specific model is proposed, based on the extensive game with imperfect information. Fairness is built in the protocol game and the corresponding game tree. To verify the property, a tree analysis method is offered, and a linear time algorithm is given. As a case study, some flaws of ASW protocol are found.