A METHOD FOR PREVENTING REPUDIATION OF AN EXECUTED TRANSACTION WITHOUT A TRUSTED THIRD PARTY

摘要

A protocol for prohibiting subsequent denial by one of the transacting partiesof an already executed electronic transaction. This protocol enables secureInternet electronic commerce without the necessity of using a trusted thirdparty. In this protocol, a sending party transmits to a receiving party, anencrypted first message that includes a desired product encrypted with arequired key, but that does not include the required key. The receiving partyuses the encrypted first message as evidence of non-repudiation of origin,i.e., evidence of non-repudiation that the sending party sent the transaction.The receiving party transmits to the sending party a second message requestingfor the required key. The sending party may use the second message as evidenceof non-repudiation of receipt, i.e., evidence of non-repudiation that thereceiving party received the transaction. Thereafter, the sending partypublishes a third message with the encrypted required key on the sendingparty's web site, and the receiving party is required to go to the web site tofetch the third message. This protocol therefore ensures non-repudiation oforigin and non-repudiation of receipt without a trusted third party involvedin the electronic transaction.