Comprehensive message control and assurance with the secure email transport protocol

Conventional email communications suffer from a myriad of vulnerabilities due to the inherent security shortcomings of SMTP. Various attributes of messages may be vulnerable to falsification, interception, and/or modification. Messages face threats from both network intruders as well as legitimate communicating parties. SETP mitigates the threats by combining a variety of security techniques into a unified system that provides the basic properties of privacy, data integrity verification, and non-repudiation. SETP goes beyond these basic assurances and also provides proof of delivery using certified timestamps, and message lifetime control using a custom-designed message key management protocol. The salient feature of SETP is its innovative addressing scheme that allows several email users to share a single transport-level email address and mailbox, providing message flow confidentiality. Every individual user can reliably retrieve their own messages from the mailbox while being restricted from compromising messages destined for any other user.