Solving Bao’s Colluding Attack in Wang’s Fair Payment Protocol

  • M. Magdalena Payeras-Capellà
  • Josep L. Ferrer Gomila
  • Llorenç Huguet Rotger
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4277)


An electronic purchase is an essential operation of electronic commerce. Fairness in the exchange of money and product, as well as anonymity of the buyer, are desirable features. In Asiacrypt 2003, C.H. Wang [8] presented a purchase protocol satisfying both anonymity and fairness, adapting the anonymous payment system of Brands [2], using a restrictive confirmation signature scheme. Later, In Asiacrypt 2004, Feng Bao [1] demonstrated that Wang’s protocol [8] can be vulnerable to attacks produced by colluding users, and he affirmed that the protocol cannot be corrected due to the anonymity of the protocol. We will show that it is possible to correct Wang’s protocol in order to avoid colluding attacks. We present a solution that modifies slightly the original protocol, maintaining the anonymity and untraceability of the original version. Finally, we discuss the convenience to achieve the property of timeliness.


Payment System Dispute Resolution Electronic Commerce Trusted Third Party Digital Product 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • M. Magdalena Payeras-Capellà
    • 1
  • Josep L. Ferrer Gomila
    • 1
  • Llorenç Huguet Rotger
    • 1
  1. 1.Universitat de les Illes BalearsPalma de MallorcaSpain

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