An efficient protocol for anonymous and fair document exchange

Fairness in document exchange has been well studied, while anonymity in the exchange, which protects the privacy of personal information such as identities and locations, has been either ignored or handled with partial or inappropriate considerations. In this paper we propose a new protocol for anonymous and fair document exchange between two parties with the assistance of an off-line trusted third party. The new protocol treats both fairness and anonymity as essential properties, employs an efficient method for off-line key recovery, and places weak requirements on the security