DomainKeys Identified Mail, or DKIM, is a system for checking the legitimacy of an email using a digital signature. When DomainKeys Identified Mail is enabled for a given domain name, a public key is published to the global DNS system and a private one is stored on the mail server. When a new email message is sent, a signature is issued using the private key and when the email is received, the signature is authenticated by the POP3/IMAP mail server using the public key. Thus, the receiver can easily tell if the message is authentic or if the sender’s email address has been forged. A discrepancy will appear if the content of the email message has been modified on its way as well, so DomainKeys Identified Mail can also be used to ensure that the sent and the received emails are identical and that nothing has been attached or removed. This validation system will boost your email security, since you can validate the genuineness of the important email messages that you receive and your associates can do the same with the messages that you send them. Based on the particular email service provider’s adopted policy, an email message that fails to pass the check may be removed or may appear in the recipient’s inbox with a warning.