DomainKeys Identified Mail, or DKIM, is a method for validating the legitimacy of an email using an e-signature. When DomainKeys Identified Mail is activated for a particular domain, a public cryptographic key is published to the global DNS system and a private one is kept on the mail server. If a new email is sent, a signature is generated using the private key and when the email is delivered, the signature is authenticated by the POP3/IMAP server using the public key. Thus, the receiver can easily distinguish if the email message is authentic or if the sender’s email address has been forged. A mismatch will appear if the content of the email message has been modified on its way as well, so DomainKeys Identified Mail can also be used to ensure that the sent and the delivered email messages are identical and that nothing has been attached or erased. This email validation system will boost your email security, as you can verify the legitimacy of the important emails 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 adopted policy, an email that fails to pass the test may be removed or may emerge in the recipient’s mailbox with a warning notification.