What is DKIM?

DKIM (DomainKeys Identified Mail) – A method created to ensure e-mail receives that a sender is an owner of an address e.g. example@domain.com , and is not trying to spoof it.

How does DKIM work?

Thanks to a properly configured SMTP server a sender inserts ciphered information about an e-mail message in headers. An asymmetric ciphering key is used for it.

Receiver seeing such information encryption, retrieves information regarding this data deciphering from sender’s domains DNS record. When the data is successfully deciphered a receiver can be certain that the message comes from address’ owner.

Naturally one more condition must be met: a key used for encrypting must be only available to the sender.

The whole process of massages deciphering happens automatically in most of e-mail service providers – e.g. Gmail, Yahoo, AOL, Hotmail etc.


DKIM is significant to all institutions that often fall victim to phishing and spoofing attacks.

Nonetheless, as number of SPAM e-mails is increasing, e-mail service providers are starting to require DKIM signature, in order to deliver messages to inboxes. Lack of DKIM signature can result in even the most trusted content ending up in SPAM folder or being blocked, by a provider, on the server level.

DKIM signature is an additional element that decreases the risk of becoming qualified as SPAM. Moreover it is highly likely that it will soon become a standard and a necessary minimum.

How to configure DKIM?

Read the article here.