DomainKeys Identified Mail, or DKIM, is a system for confirming the genuineness of an email by using a digital signature. When DomainKeys Identified Mail is activated for a certain domain, a public cryptographic key is published to the global Domain Name System and a private one is kept on the email server. If a new email message is sent, a signature is generated using the private key and when the message is received, the signature is verified by the POP3/IMAP email server using the public key. In this way, the recipient can easily discern if the email message is genuine 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 delivered emails are identical and that nothing has been attached or deleted. This email authentication system will enhance your email security, since you can verify the legitimacy of the important email messages that you receive and your partners can do likewise with the emails that you send them. Based on the given email service provider’s policy, an email message that fails the examination may be removed or may appear in the receiver’s mailbox with a warning symbol.