Optimizing One Fair Document Exchange Protocol
  This paper presents an efficient fair document exchange protocol. The exchange of the documents will be between two parties. The protocol is based on the verifiable and recoverable encryption of a document's key. This verifiable and recoverable encryption of the document's key will allow one party to verify the encrypted key. It will also ensure this party that the Semi Trusted Third Party will be able to recover the key if the other party misbehaves. The protocol also incorporates the concept of enforcing the honesty of one party. The proposed protocol consists of only three messages and is more efficient than related protocols. 
Abdullah M. Alaraj
cs.CR