DomainKeys Identified Mail, or DKIM, is a system for checking the legitimacy of an email message by using an electronic signature. When DKIM is activated for a particular domain name, a public key is published to the global DNS database and a private one is stored on the email server. If a new email message is sent, a signature is generated using the private key and when the email is delivered, that signature is authenticated by the POP3/IMAP email server using the public key. In this way, the receiver 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 changed in the meantime 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 authentication system will heighten your email safety, since you can verify the legitimacy of the important emails that you receive and your colleagues can do the exact same thing with the messages that you send them. Depending on the given email provider’s policy, an email message that fails the test may be deleted or may enter the receiver’s inbox with a warning notification.