DomainKeys Identified Mail (DKIM) is a validation system used to verify that an email message has been sent by an authenticated email server or person. A digital signature is added to the email message’s header by using a private cryptographic key. When the message is received, a public key that is available in the global DNS database is used to confirm who actually sent it and if its content has been modified in any way. The primary job of DomainKeys Identified Mail is to stop the widespread spam and scam messages, as it makes it impossible to fake an email address. If an email is sent from an email address claiming to belong to your bank or financial institution, for example, but the signature doesn’t match, you will either not get the message at all, or you will get it with a warning that most probably it’s not a genuine one. It depends on mail service providers what exactly will happen with an email that fails to pass the signature check. DomainKeys Identified Mail will also provide you with an added layer of safety when you communicate with your business associates, for example, as they can see for themselves that all the e-mails that you send are authentic and haven’t been tampered with on their way.