A formal model of fair exchange protocols  

作　　者：QING Sihan1,2,3 & LI Gaicheng1,2,3 1. Engineering Research Center for Information Security Technology, Institute of Software, Chinese Aca- demy of Sciences, Beijing 100080, China 2. Beijing Zhongke Ansheng Corporation of Information Technology, Beijing 100080, China 3. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China 

出　　处：《Science in China(Series F)》2005年第4期499-512,共14页中国科学（F辑英文版）

基　　金：the Natural Science Foundation ofBeijing(Grant No.4052016);the National Natural Science Foundation of China(Grant No.60083007); the National Grand Fundamental Research 973 Program ofChina(Grant No.G1999035802).

摘　　要：Based on the study of existing fair exchange protocols, this paper sets up an accurate formal model by stepwise refinement. In the process of refinement an unreliable channel is employed to simulate an attack behavior. The model provides a novel formal definition of exchanged items, and presents the formal goals for fairness, accountability, etc., reflecting the inherent requirements for fair exchange protocols across-the-board. In order to check, prove, and design fair exchange protocols effectively and efficiently, the model puts forward a novel property of abuse-freeness which applies to all fair exchange protocols, gives a formal definition for trust strand of the third party, and presents general criteria of designing a secure and effective fair exchange protocol. Taking a typical fair exchange protocol as an example, this paper presents the analysis steps of fair exchange protocols appealing to our model. An unknown attack is uncovered. The analysis reveals the process of a complete attack, discovering deeper reasons for causing an attack. Finally, we modify the flawed protocol and the revised protocol ensures the desirable properties.Based on the study of existing fair exchange protocols, this paper sets up an accurate formal model by stepwise refinement. In the process of refinement an unreliable channel is employed to simulate an attack behavior. The model provides a novel formal definition of exchanged items, and presents the formal goals for fairness, accountability, etc., reflecting the inherent requirements for fair exchange protocols across-the-board. In order to check, prove, and design fair exchange protocols effectively and efficiently, the model puts forward a novel property of abuse-freeness which applies to all fair exchange protocols, gives a formal definition for trust strand of the third party, and presents general criteria of designing a secure and effective fair exchange protocol. Taking a typical fair exchange protocol as an example, this paper presents the analysis steps of fair exchange protocols appealing to our model. An unknown attack is uncovered. The analysis reveals the process of a complete attack, discovering deeper reasons for causing an attack. Finally, we modify the flawed protocol and the revised protocol ensures the desirable properties.

关 键 词：EVENTS local causal relation local temporal relation global relation exchanged item security  goals. 

分 类 号：TN402[电子电信—微电子学与固体电子学]