DomainKeys Identified Mail, or DKIM, is a system for verifying the legitimacy of an email message using a digital signature. When DKIM is activated for a particular domain, a public encryption key is published to the global DNS database and a private one is kept on the email server. When a new email message is sent, a signature is generated using the private key and when the email is received, the signature is validated by the POP3/IMAP mail server using the public key. Thus, the recipient can easily recognize if the message is genuine or if the sender’s address has been spoofed. A mismatch will appear if the content of the email message has been changed in the meantime as well, so DomainKeys Identified Mail can also be used to make sure that the sent and the received messages are identical and that nothing has been added or removed. This validation system will heighten your email security, as you can validate the genuineness of the important email messages that you get and your partners can do the same with the messages that you send them. Depending on the given email service provider’s policies, an email message that fails to pass the test may be removed or may appear in the recipient’s mailbox with a warning sign.