Amazon.com, Inc.
Electronic message authentication

Abstract:

An electronic message delivery service receives a request to transmit an electronic message to a recipient. In response to the request, the electronic message delivery service determines first information from the electronic message usable to uniquely identify the electronic message. The electronic message delivery service obtains, based at least in part on the first information and a cryptographic key, cryptographic information that can be inserted into the electronic message. The electronic message delivery service inserts the cryptographic information and second information usable to validate at least a portion of the electronic message with the cryptographic information into the electronic message. The electronic message is transmitted to the recipient.