DomainKeys Identified Mail (DKIM) is an email authentication system used to prove that an e-mail has been sent by an authenticated server or person. An electronic signature is attached to the header of the message by using a private cryptographic key. When the email is received, a public key that is available in the global DNS database is used to validate who actually sent it and if the content has been altered in some way. The chief job of DKIM is to obstruct the widely spread scam and spam emails, as it makes it impossible to forge an email address. If an email is sent from an address claiming to belong to your bank, for instance, but the signature does not match, you will either not get the email at all, or you’ll receive it with a warning notification that most probably it is not an authentic one. It depends on email service providers what exactly will happen with an email which fails to pass the signature test. DomainKeys Identified Mail will also supply you with an added layer of security when you communicate with your business allies, for instance, since they can see that all the e-mails that you send are genuine and haven’t been meddled with on their way.