DomainKeys Identified Mail, or DKIM, is a method for validating the authenticity of an email by using an electronic signature. When DomainKeys Identified Mail is activated for a given domain name, a public cryptographic key is published to the global DNS system and a private one is stored on the mail server. If a new email message is sent, a signature is issued using the private key and when the message is delivered, that signature is verified by the incoming POP3/IMAP email server using the public key. In this way, the recipient can easily know if the email message is authentic or if the sender’s address has been forged. A mismatch will appear if the content of the email has been changed in the meantime as well, so DKIM can also be used to ensure that the sent and the received emails are identical and that nothing has been attached or deleted. This email validation system will strengthen your email security, as you can confirm the authenticity of the important emails that you get and your partners can do the exact same thing with the emails that you send them. Depending on the given email service provider’s policy, an email message that fails the examination may be erased or may show up in the recipient’s inbox with a warning.