I co-authored and developed the Message Level Authentication Protocol (MLAP) in early 2003, which was an end-to-end email authentication protocol designed to stop spoofing and thus spam. This was before DKIM and SenderID and a real shame that patents and investors couldn’t get behind it fast enough. I still have hope in the technology and long to see it solve the spam problem. Now all that is left is remnants of several free applications that I developed including a Mozilla Thunderbird add-on, https://addons.mozilla.org/en-US/thunderbird/addon/2260.
The core question of the protocol was
“Did you (the purported sender) send me this message?”
The protocol then went to query the purported sender and got an answer to this question. If you sent the message you have a record of sending it and using MLAP this record was easy to look up. And if you didn’t send it you now had a copy of the message, which could then be posted to anti-phishing mechanisms.
Launched: Mar 2003