DomainKeys Identified Mail, or DKIM, is a method for validating the genuineness of an email using a digital signature. When DKIM is enabled for a given domain name, a public cryptographic key is published to the global DNS database and a private one is stored on the email server. When a new message is sent, a signature is issued using the private key and when the message is received, that signature is authenticated by the incoming POP3/IMAP email server using the public key. In this way, the recipient can easily know if the message is legitimate or if the sender’s email address has been spoofed. A mismatch will occur if the content of the email has been modified in the meantime as well, so DomainKeys Identified Mail can also be used to make sure that the sent and the received emails are identical and that nothing has been attached or removed. This email authentication system will increase your email safety, since you can confirm the genuineness of the important email messages that you get and your colleagues can do likewise with the email messages that you send them. Based on the particular mail service provider’s policy, an email message that fails to pass the test may be removed or may end up in the recipient’s inbox with a warning notification.
