DomainKeys Identified Mail, or DKIM, is a method for validating the genuineness of an email by using an electronic signature. When DomainKeys Identified Mail is activated for a given domain, a public key is published to the global DNS database and a private one is kept on the mail server. When a new email message is sent, a signature is generated using the private key and when the email is delivered, the signature is verified by the incoming POP3/IMAP server using the public key. In this way, the recipient can easily tell if the email message is authentic or if the sender’s email address has been spoofed. A mismatch will appear if the content of the email message has been altered 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 attached or erased. This validation system will increase your email security, as you can confirm the legitimacy of the important email messages that you get and your colleagues can do likewise with the messages that you send them. Based on the given mail service provider’s adopted policy, an email message that fails the check may be deleted or may show up in the receiver’s inbox with a warning.