DomainKeys Identified Mail (DKIM) is an email validation system used to confirm that an email message has been sent by an authenticated person or server. A digital signature is added to the header of the email message by using a private cryptographic key. When the message is received, a public key that is available in the global Domain Name System is used to confirm who actually sent it and whether its content has been edited in some way. The chief job of DomainKeys Identified Mail is to impede the widespread spam and scam messages, as it makes it impossible to fake an email address. If a message is sent from an address claiming to belong to your bank, for example, but the signature does not correspond, you will either not receive the email message at all, or you will get it with a warning that most likely it is not legitimate. It depends on email providers what exactly will happen with an email that fails to pass the signature check. DKIM will also offer you an additional layer of safety when you communicate with your business associates, for instance, as they can see for themselves that all the e-mails that you send are authentic and haven’t been modified on their way.