DomainKeys Identified Mail (DKIM) is an email validation system used to check that an email message has been sent by an authorized individual or mail server. An electronic signature is added to the message’s header using a private encryption key. When the message is received, a public key that’s available in the global DNS database is used to confirm who exactly sent it and whether its content has been modified in any way. The primary function of DKIM is to hinder the widely spread spam and scam email messages, as it makes it impossible to fake an email address. If an email message is sent from an email address claiming to belong to your bank or financial institution, for instance, but the signature doesn’t match, you will either not get the email at all, or you will get it with an alert that most probably it is not a genuine one. It depends on email providers what exactly will happen with an email message that fails to pass the signature examination. DomainKeys Identified Mail will also provide you with an added layer of protection when you communicate with your business partners, for instance, since they can see that all the e-mail messages that you send are authentic and have not been meddled with on their way.