DomainKeys Identified Mail, or DKIM, is a system for checking the genuineness of an email by using a digital signature. When DKIM is activated for a certain domain name, a public key is published to the global DNS system and a private one is kept on the mail server. If a new message is sent, a signature is issued using the private key and when the email is received, that signature is authenticated by the receiving 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 mismatch will appear 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 delivered email messages are identical and that nothing has been attached or deleted. This validation system will strengthen your email security, since you can verify the legitimacy of the important emails that you get and your colleagues can do likewise with the emails that you send them. Based on the given email provider’s policy, an email that fails the examination may be deleted or may reach the receiver’s mailbox with a warning alert.