DomainKeys Identified Mail, or DKIM, is a system for checking the authenticity of an email message by using an electronic signature. When DomainKeys Identified Mail is activated for a particular domain name, a public encryption key is published to the global DNS system and a private one is kept on the email server. When a new email is sent, a signature is generated using the private key and when the message is received, that signature is checked by the POP3/IMAP mail server using the public key. Thus, the receiver can easily recognize if the email is legitimate or if the sender’s address has been forged. A discrepancy 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 delivered email messages are identical and that nothing has been attached or deleted. This email authentication system will increase your email safety, as you can verify the legitimacy of the important emails that you receive and your associates can do the same with the email messages that you send them. Depending on the particular email provider’s adopted policy, a message that fails the examination may be removed or may reach the receiver’s mailbox with a warning sign.