DomainKeys Identified Mail (DKIM) is an email validation system used to confirm that an email has been sent by an authenticated person or server. An e-signature is added to the header of the message using a private key. When the message is received, a public key that is available in the global DNS database is used to verify who exactly sent it and whether its content has been edited in some way. The fundamental task of DKIM is to block the widely spread spam and scam emails, as it makes it impossible to forge 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 doesn’t match, you will either not receive the email at all, or you’ll receive it with a warning notice that most likely it’s not an authentic one. It depends on email service providers what exactly will happen with an email which fails the signature test. DomainKeys Identified Mail will also supply you with an added layer of safety when you communicate with your business associates, for instance, since they can see that all the email messages that you exchange are authentic and haven’t been manipulated in the meantime.