DomainKeys Identified Mail, or DKIM, is a method for verifying the legitimacy of an email message using an e-signature. When DKIM is activated for a specific domain, 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 is sent, a signature is generated using the private key and when the message is received, the signature is validated by the incoming POP3/IMAP server using the public key. In this way, the receiver can easily distinguish if the message is authentic or if the sender’s email address has been forged. A mismatch will appear if the content of the email has been changed on its way as well, so DKIM can also be used to make sure that the sent and the received email messages are identical and that nothing has been attached or deleted. This authentication system will heighten your email security, since you can validate the genuineness of the important emails that you get and your colleagues can do the exact same thing with the messages that you send them. Based on the given email service provider’s policies, an email message that fails to pass the check may be erased or may appear in the recipient’s inbox with a warning alert.