DomainKeys Identified Mail, or DKIM, is a system for confirming the authenticity of an email by using a digital signature. When DKIM is activated for a given domain name, a public cryptographic key is published to the global DNS database 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 message is delivered, that signature is validated by the incoming mail server using the public key. In this way, the recipient can easily distinguish 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 changed in the meantime 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 attached or erased. This authentication system will strengthen your email safety, as you can validate the legitimacy of the important emails that you receive and your partners can do likewise with the messages that you send them. Depending on the given mail service provider’s adopted policies, a message that fails to pass the check may be removed or may show up in the recipient’s mailbox with a warning.