DomainKeys Identified Mail, or DKIM, is a system for validating the legitimacy of an email message by using an e-signature. When DKIM is enabled for a given domain, a public cryptographic key is published to the global DNS system and a private one is stored on the email server. If a new message is sent, a signature is generated using the private key and when the message is received, the signature is checked by the incoming POP3/IMAP email server using the public key. In this way, the receiver can easily recognize if the message is authentic or if the sender’s email address has been spoofed. A mismatch will occur if the content of the email message has been edited in the meantime as well, so DKIM can also be used to make sure that the sent and the received messages are identical and that nothing has been attached or erased. This email authentication system will strengthen your email security, since you can verify the legitimacy of the important email messages that you get and your associates can do likewise with the messages that you send them. Based on the given mail service provider’s policies, an email that fails to pass the test may be removed or may emerge in the receiver’s mailbox with a warning symbol.
