DomainKeys Identified Mail, or DKIM, is a system for verifying the legitimacy of an email using an electronic signature. When DKIM is enabled for a given domain name, a public key is published to the global Domain Name System and a private one is kept on the email server. When a new email is sent, a signature is issued using the private key and when the email message is received, the signature is ‘scanned’ by the incoming POP3/IMAP email server using the public key. Thus, the receiver can easily discern if the email 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 altered in the meantime as well, so DKIM 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 authentication system will heighten your email security, as you can confirm the genuineness of the important email messages that you receive and your colleagues can do likewise with the messages that you send them. Depending on the given mail service provider’s adopted policy, an email that fails to pass the check may be removed or may end up in the recipient’s mailbox with a warning alert.