DomainKeys Identified Mail, or DKIM, is a method for validating the authenticity of an email using a digital signature. When DKIM is enabled for a certain domain, a public cryptographic 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 issued using the private key and when the email is delivered, the signature is authenticated by the incoming mail server using the public key. Thus, the recipient can easily discern if the email is legitimate or if the sender’s email address has been forged. A mismatch will occur if the content of the email message has been modified on its way as well, so DomainKeys Identified Mail can also be used to ensure that the sent and the delivered messages are identical and that nothing has been added or removed. This email authentication system will boost your email security, as you can verify the legitimacy of the important emails that you get and your partners can do the same with the emails that you send them. Depending on the particular mail service provider’s policy, an email that fails the test may be removed or may appear in the receiver’s inbox with a warning flag.