domain keys identified mail (DKIM)

Domain Keys Identified Mail (DKIM) is a method to distinguish spam from legitimate messages.

DKIM is an alternative to Sender Policy Framework( SPF) and was proposed to the Internet Engineering Task Force( IETF) by Cisco and Yahoo for standardization.

With DKIM, outgoing mail is signed with a private key. The recipient-side mail clients verify that the key in the message comes from the known source. To do this, they use a combination of the Domain NameSystem( DNS) and public key. DKIM can therefore also evaluate the integrity of the message.

The DKIM procedure requires that both the mail server and the mail client support the procedure.