DomainKeys Identified Mail, or DKIM, is a method for verifying the genuineness of an email message using an e-signature. When DomainKeys Identified Mail is enabled for a given domain name, a public cryptographic key is published to the global DNS database and a private one is kept on the mail server. If a new email message is sent, a signature is issued using the private key and when the email message is received, that signature is authenticated by the POP3/IMAP server using the public key. In this way, the recipient can easily distinguish if the email message is legitimate or if the sender’s address has been spoofed. A discrepancy will appear if the content of the email message has been changed on its way as well, so DomainKeys Identified Mail can also be used to ensure that the sent and the received emails are identical and that nothing has been added or removed. This email authentication system will boost your email security, since you can validate the genuineness of the important email messages that you get and your colleagues can do the same with the messages that you send them. Depending on the given email provider’s policy, an email message that fails to pass the test may be removed or may be delivered to the receiver’s inbox with a warning symbol.
