DomainKeys Identified Mail, or DKIM, is a system for validating the legitimacy of an email using an electronic signature. When DomainKeys Identified Mail is enabled for a specific domain name, a public key is published to the global Domain Name System and a private one is stored on the mail server. When a new email is sent, a signature is issued using the private key and when the email is received, the signature is ‘scanned’ by the receiving server using the public key. In this way, the receiver can easily recognize if the email is legitimate or if the sender’s email address has been forged. A discrepancy will appear if the content of the email has been changed in the meantime as well, so DomainKeys Identified Mail can also be used to ensure that the sent and the delivered emails are identical and that nothing has been added or erased. This email validation system will increase your email security, as you can verify the genuineness of the important email messages that you receive and your partners can do the exact same thing with the email messages that you send them. Depending on the particular mail service provider’s policy, a message that fails to pass the check may be deleted or may end up in the receiver’s mailbox with a warning sign.