Electronic proof of receipt

摘要

A system for use in an electronic cryptosystem for providing a sender with electronic proof of receipt by an intended recipient of an electronic artifact is disclosed. The process is initiated by the recipient's requesting an artifact from the sender, who then obtains the recipient's transmission key and separately encrypts the requested artifact and an acknowledgment such that they are decryptable with first and second strictly private keys, respectively, known to and controlled by the sender. Next, the sender encrypts the encrypted artifact and encrypted acknowledgment together using the transmission key such that the message is decryptable only with a third strictly private key known to and controlled by the recipient, and transmits the encrypted message to the recipient. The recipient decrypts the message to recover the encrypted artifact, as well as the encrypted acknowledgment which is returned to the sender. The sender decrypts the acknowledgment using the second strictly private key to verify receipt by the recipient of the encrypted artifact and then sends the first strictly private key to the recipient to enable decryption of the encrypted artifact. Additionally, at least one alternative embodiment is disclosed for enabling a sender to prove to third parties that the intended recipient in fact received the requested artifact.