DomainKeys Identified Mail, or DKIM, is a method for verifying the genuineness of an email message by using an electronic signature. When DKIM is activated for a certain domain, a public 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 message is delivered, the signature is authenticated by the POP3/IMAP email server using the public key. Thus, the recipient can easily know if the email is authentic or if the sender’s address has been forged. A mismatch will occur if the content of the email message has been changed on its way as well, so DKIM 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 enhance your email security, as you can confirm the authenticity of the important email messages that you get and your colleagues can do likewise with the emails that you send them. Based on the given mail service provider’s adopted policies, a message that fails the test may be erased or may end up in the receiver’s inbox with a warning symbol.