Domain Keys Identified Mail
DKIM is a technology to help prevent domain name impersonation ("phishing") and abuse. DKIM does not directly filter nor identify junk mail, but aids in spam filtering and identity theft by preventing spammers from forging mail from a domain they do not own or belong to. Message headers and content sent by a user within a domain are digitally-signed using private-public key cryptography. The receiver of a message with a DKIM header will use the sender's domain to fetch the associated public key stored within the DNS to verify that the message has been signed by the domain in question and that the message has not been tampered with.