DomainKeys Identified Mail, or DKIM, is a system for verifying the genuineness of an email using a digital signature. When DomainKeys Identified Mail is activated for a certain domain, a public encryption key is published to the global Domain Name System and a private one is kept on the mail server. When a new email is sent, a signature is issued using the private key and when the email is delivered, that signature is ‘scanned’ by the incoming server using the public key. In this way, the recipient can easily know if the message is legitimate or if the sender’s email address has been forged. A discrepancy will occur if the content of the email message has been edited in the meantime as well, so DKIM can also be used to ensure that the sent and the received email messages are identical and that nothing has been added or removed. This email authentication system will increase your email security, since you can validate the legitimacy of the important email messages that you receive and your associates can do the exact same thing with the emails that you send them. Based on the particular email service provider’s policies, a message that fails to pass the check may be deleted or may be delivered to the recipient’s inbox with a warning flag.