DomainKeys Identified Mail (DKIM) is an email validation system used to confirm that an email has been sent by an authorized individual or email server. An electronic signature is attached to the message’s header by using a private key. When the message is received, a public key that is available in the global Domain Name System is used to check who actually sent it and whether the content has been altered in any way. The main job of DKIM is to hamper the widespread scam and spam emails, as it makes it impossible to fake an email address. If an email is sent from an 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 message at all, or you’ll get it with an alert that most likely it’s not an authentic one. It depends on mail service providers what exactly will happen with an email which fails the signature examination. DomainKeys Identified Mail will also supply you with an extra layer of security when you communicate with your business associates, for instance, as they can see that all the messages that you send are legitimate and have not been manipulated on their way.