The research on off-line electronic cash(e-cash) schemes has drawn much attention since Chaum etc [8] presented the first off-line anonymous electronic cash scheme in 1988. However, anonymous electronic cash schemes also facilitate fraud and criminal activities [32], such as money laundering, blackmailing and illegal purchases. Frankel etc [13]. first introduces the concept of fair electronic c...

The fairness of data exchange becomes a key factor for the transaction over the Internet. To ensure the fairness of data exchange, the protocol needs a trusted third party be a judge when the dispute occurs, and has to give a guarantee to main parties during the data exchange. To eliminate the third party’s connectional time and enhance its security, a fair-exchange protocol based on off-line s...

How to sign an electronic contract online between two parties (say Alice and Bob) in a fair manner is an interesting problem, and has been studied for a long time. Optimistic Fair Exchange (OFE) is an efficient solution to this problem, in which a semi-trusted third party named arbitrator is called in to resolve a dispute if there is one during an exchange between Alice and Bob. Recently, sever...

In this paper we consider the optimistic approach of the non-repudiation protocols. We study a non-repudiation protocol with off-line trusted third party and we keep on with the definition of the multi-party non-repudiation, compare it to multi-party fair exchange and show some fundamental differences between these two problems. Finally, we generalize our protocol and propose a multi-party non-...

In this paper we provide protocols for fair lottery and casino games. These fair protocols enable to remove the trust from the casino/lottery without resorting to another trusted third party, by allowing the user playing the game to participate in the generation of the specific run of the game. Furthermore, the user is able to verify the correctness of the execution of the game at the end of th...

This paper proposes a fair electronic gambling scheme for the Internet. The proposed scheme provides a unique link between payment and gambling outcome so that the winner can be ensured to get the payment. Since an optimal fair exchange method is used in gambling message exchange, the proposed system guarantees that no one can successfully cheat during a gambling process. Our system requires an...