Fair payment protocol with semi-trusted third party

摘要

Described is an optimistic fair payment protocol in electronic commerce that provides fair payment while resisting an unconscious double spending attack and other attacks. A buyer receives encrypted e-goods from a merchant, and sends payment to the merchant. If decryption information is not received in exchange for the payment, or the decryption information does not render the e-goods useable, the buyer launches a dispute with a third party dispute resolution service. If the decryption information is received and renders the e-goods useable, the buyer determines whether the e-goods are valid, according to a corresponding description. If not valid, the buyer launches a dispute and provides the e-goods and the description. The third party uses the description to evaluate the validity of the goods to determine whether to refund the payment to the buyer or release it to the merchant.

主权项

1. A computer-implemented method performed by a buyer apparatus, the computer-implemented method comprising:
receiving encrypted e-goods, a transaction agreement including a description of the e-goods, and a digital signature from a merchant as part of a transaction; validating the transaction agreement including the description of the e-goods using the digital signature; when the transaction agreement is validated, sending payment from the buyer apparatus to the merchant; determining whether decryption data has been received from the merchant in exchange for the payment; in a first instance, responsive to determining that the decryption data has not been received from the merchant, launching a dispute with a third party other than the merchant; in a second instance, responsive to determining that the decryption data has been received from the merchant, determining whether the decryption data received from the merchant is sufficient for the buyer apparatus to decrypt the encrypted e-goods without obtaining further decryption data, and:
a) responsive to determining that the decryption data received from the merchant is not sufficient for the buyer apparatus to decrypt the e-goods, launching the dispute with the third party, orb) responsive to determining that the decryption data is sufficient for the buyer apparatus to decrypt the encrypted e-goods, determining whether the e-goods received from the merchant are valid by decrypting the e-goods with the decryption data and comparing the e-goods to the description of the e-goods in the transaction agreement, and:
i) when the e-goods are not valid, launching the dispute with the third party; andii) when the e-goods are valid, terminating the transaction without launching the dispute, wherein the payment is sent from the buyer apparatus to the merchant after the buyer apparatus receives the encrypted e-goods and before the buyer apparatus determines whether the decryption data has been received.