DomainKeys Identified Mail, or DKIM, is a method for validating the legitimacy of an email message using a digital signature. When DomainKeys Identified Mail is activated for a specific domain, a public cryptographic 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 generated using the private key and when the email is received, the signature is checked by the incoming email server using the public key. In this way, the receiver can easily distinguish if the message is genuine or if the sender’s address has been spoofed. A mismatch will appear if the content of the email has been altered in the meantime as well, so DKIM can also be used to ensure that the sent and the delivered emails are identical and that nothing has been added or erased. This authentication system will increase your email security, as you can confirm the legitimacy of the important emails that you receive and your associates can do the exact same thing with the messages that you send them. Depending on the particular email service provider’s policies, a message that fails the test may be deleted or may reach the recipient’s mailbox with a warning.