DomainKeys Identified Mail (DKIM): Using Digital Signatures for Domain Verification

Email protocols were not designed to provide protection against falsification of a message’s address of origin, referred to as “spoofing”. DomainKeys Identified Mail (DKIM) defines a mechanism for using digital signatures on email at the domain level, allowing the receiving domain to confirm that mail came from the domain it claims to. Using the associated DKIM sender signing policy specification, the receiving domain may also have more information for deciding how to treat mail without a valid signature. The use of DKIM signatures and signing policies gives sending domains one tool to help recipients identify legitimate messages from their domain, and a reliable identifier that can be used to combat spam and phishing.

By: Barry Leiba; Jim Fenton

Published in: RC23995 in 2006


This Research Report is available. This report has been submitted for publication outside of IBM and will probably be copyrighted if accepted for publication. It has been issued as a Research Report for early dissemination of its contents. In view of the transfer of copyright to the outside publisher, its distribution outside of IBM prior to publication should be limited to peer communications and specific requests. After outside publication, requests should be filled only by reprints or legally obtained copies of the article (e.g., payment of royalties). I have read and understand this notice and am a member of the scientific community outside or inside of IBM seeking a single copy only.


Questions about this service can be mailed to .