DomainKeys Identified Mail (DKIM) is an email validation system used to verify that an email message has been sent by an authorized mail server or person. An electronic signature is attached to the header of the message by using a private encryption key. When the email message is received, a public key that’s available in the global Domain Name System is used to verify who actually sent it and if the content has been altered in some way. The principal task of DKIM is to hinder the widely spread spam and scam email messages, as it makes it impossible to fake an email address. If a message is sent from an address claiming to belong to your bank or financial institution, for instance, but the signature does not correspond, you will either not get the email message at all, or you will get it with a warning that most likely it’s not genuine. It depends on email providers what exactly will happen with an email that fails the signature test. DKIM will also provide you with an extra layer of protection when you communicate with your business partners, for example, as they can see that all the e-mail messages that you exchange are legitimate and haven’t been manipulated on their way.
