DomainKeys Identified Mail, or DKIM, is a system for validating the genuineness of an email by using a digital signature. When DKIM is activated for a given domain, a public key is published to the global Domain Name System and a private one is kept on the mail server. When a new email message is sent, a signature is issued using the private key and when the message is received, that signature is verified by the incoming email server using the public key. In this way, the receiver can easily discern if the message is authentic or if the sender’s address has been spoofed. A mismatch will appear if the content of the email has been changed in the meantime as well, so DomainKeys Identified Mail can also be used to ensure that the sent and the delivered emails are identical and that nothing has been attached or deleted. This email authentication system will strengthen your email security, as you can validate the genuineness of the important emails that you receive and your partners can do the exact same thing with the emails that you send them. Based on the particular email provider’s policy, an email message that fails the test may be removed or may reach the receiver’s inbox with a warning notification.
