DomainKeys Identified Mail, or DKIM, is a method for checking the authenticity of an email message by using an e-signature. When DomainKeys Identified Mail is activated for a certain domain name, a public encryption key is published to the global DNS system and a private one is stored on the mail server. When a new message is sent, a signature is issued using the private key and when the message is received, the signature is checked by the incoming server using the public key. Thus, the recipient can easily discern if the message is genuine or if the sender’s email address has been forged. A mismatch will occur if the content of the email has been edited on its way as well, so DKIM can also be used to ensure that the sent and the received email messages are identical and that nothing has been attached or removed. This authentication system will strengthen your email security, as you can verify the legitimacy of the important email messages that you receive and your colleagues can do likewise with the messages that you send them. Based on the particular mail service provider’s adopted policies, an email that fails to pass the examination may be removed or may end up in the recipient’s mailbox with a warning sign.