DomainKeys Identified Mail (DKIM) is an email validation system used to confirm that an email has been sent by an authenticated individual or email server. A digital signature is attached to the header of the message using a private key. When the email is received, a public key that is available in the global Domain Name System is used to confirm who actually sent it and if the content has been altered in any way. The prime function of DKIM is to block the widespread spam and scam emails, as it makes it impossible to forge an email address. If an email message is sent from an address claiming to belong to your bank or financial institution, for example, but the signature doesn’t match, you will either not get the message at all, or you’ll receive it with an alert that most probably it is not legitimate. It depends on email service providers what exactly will happen with an email which fails to pass the signature test. DKIM will also provide you with an additional layer of safety when you communicate with your business partners, for instance, as they can see that all the email messages that you send are genuine and have not been modified in the meantime.