DomainKeys Identified Mail, or DKIM, is a method for confirming the authenticity of an email by using a digital signature. When DomainKeys Identified Mail is enabled for a specific domain, a public encryption key is published to the global DNS database and a private one is kept on the mail server. When a new email is sent, a signature is generated using the private key and when the email message is received, the signature is checked by the incoming email server using the public key. Thus, the recipient can easily recognize if the email message is authentic or if the sender’s address has been spoofed. A mismatch will appear if the content of the email message has been modified in the meantime as well, so DomainKeys Identified Mail can also be used to make sure that the sent and the received emails are identical and that nothing has been attached or deleted. This email authentication system will increase your email security, since you can validate the legitimacy of the important emails that you receive and your colleagues can do the exact same thing with the messages that you send them. Depending on the particular email provider’s policy, an email message that fails the examination may be deleted or may show up in the recipient’s inbox with a warning.
