In this paper, we introduce a new and natural paradigm for fair exchange protocols, called verifiable probabilistic signature scheme. A security model with precise and formal definitions is presented, and an RSA-based efficient and provably secure verifiable probabilistic signature scheme is proposed. Our scheme works well with standard RSA signature schemes, and the proposed optimistic fair ex...

This paper introduces a natural paradigm for fair exchange protocols, called ID-based partial proxy signature scheme. A security model with precise and formal definitions is presented, and an efficient and provably secure partial proxy signature scheme is proposed. This is a full ID-based optimistic fair exchange protocol. Unlike the vast majority of previously proposed protocols, this approach...

Optimistic fair exchange (OFE) is a kind of protocols for solving the fair exchange problem between two participants with the help of an arbitrator that only needs to be involved when dispute occurs. As far as we are concerned, all previous work on OFE does not take into account user’s attributes such as nationality and age. We identify that in some applications, the attributes could play an im...

A contract signing protocol lets two parties exchange digital signatures on a pre-agreed text. Optimistic contract signing protocols enable the signers to do so without invoking a trusted third party. However, an adjudicating third party remains available should one or both signers seek timely resolution. We analyze optimistic contract signing protocols using a game-theoretic approach and prove...

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...

Optimistic fair exchange (OFE) is a kind of protocol to guarantee fairness for the parties involved in an exchange with the help of an arbitrator. A fundamental work of optimistic fair exchange is to define security models capturing realistic attacks and design schemes secure in practical models. The security models are very essential to ensure that they capture practical situation, which will ...

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...