DomainKeys Identified Mail, or DKIM, is a method for validating the genuineness of an email using a digital signature. When DomainKeys Identified Mail is activated for a given domain name, a public encryption key is published to the global DNS system and a private one is kept on the mail server. When a new email message is sent, a signature is issued using the private key and when the email is delivered, that signature is ‘scanned’ by the POP3/IMAP email server using the public key. Thus, the recipient can easily discern if the email is authentic or if the sender’s address has been spoofed. A mismatch will occur if the content of the email has been modified on its way as well, so DKIM can also be used to make sure that the sent and the delivered emails are identical and that nothing has been attached or removed. This validation system will increase your email security, since you can confirm the authenticity of the important emails that you get and your colleagues can do likewise with the emails that you send them. Based on the particular email service provider’s policies, an email message that fails to pass the check may be erased or may appear in the recipient’s inbox with a warning alert.