DomainKeys Identified Mail, or DKIM, is a system for checking the genuineness of an email message by using an electronic signature. When DKIM is activated for a specific domain, a public encryption 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 message is delivered, the signature is authenticated by the POP3/IMAP mail server using the public key. Thus, the receiver can easily know if the email message is genuine or if the sender’s address has been forged. A mismatch will appear if the content of the email has been altered on its way as well, so DomainKeys Identified Mail can also be used to make sure that the sent and the delivered messages are identical and that nothing has been added or deleted. This validation system will heighten your email security, since you can validate the authenticity of the important emails that you receive and your partners can do likewise with the email messages that you send them. Depending on the particular email provider’s policy, an email that fails to pass the test may be erased or may show up in the receiver’s mailbox with a warning notification.