DomainKeys Identified Mail (DKIM) is an email authentication system used to check that an email has been sent by an authorized server or person. An electronic signature is attached to the message’s header 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 exactly sent it and whether its content has been modified in any way. The chief function of DomainKeys Identified Mail is to impede the widespread scam and spam 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 example, but the signature does not match, you will either not get the email message at all, or you’ll receive it with a warning note that most likely it’s not authentic. It depends on email service providers what exactly will happen with an email which fails the signature test. DomainKeys Identified Mail will also provide you with an added safety layer when you communicate with your business associates, for example, as they can see that all the email messages that you send are genuine and haven’t been manipulated in the meantime.