Recently the IETF DKIM Working Group concluded discussion pertaining to Email Authentication. For Email Authentication this was a major win as DKIM shows much promise to help ISPs better understand where a message originated and to help determine such benefits as the potential of recognizing and establishing a protocol for domain reputation.

DKIM provides a reliable identifier which is a sufficient way to determine that the entity which sent this message, also sent this other message which was signed by the same key. It’s also a method of associating a domain name to an email, allowing on organization to assume responsibility that is validated by its recipients. Validation is based on public-key cryptography. This allows MTAs such as Port25 to sign email messages that pass through them and also verify a signature attached to an incoming email. These signatures are linked to domain names and the public keys are published via DNS.

More than one DKIM signature is supported for those that engage in this strategy, as well as to allow for compliance with any Feedback Loop (FBL) requirements set by remote ISPs or mailbox providers.