DomainKeys Identified Mail (DKIM) is an email authentication system used to verify that an e-mail has been sent by an authorized mail server or individual. An e-signature is attached to the header of the email message using a private cryptographic key. When the email is received, a public key that is available in the global Domain Name System is used to check who actually sent it and if its content has been modified in any way. The prime task of DKIM is to stop the widespread spam and scam messages, as it makes it impossible to forge an email address. If a message is sent from an email address claiming to belong to your bank, for example, but the signature does not correspond, you will either not receive the message at all, or you’ll get it with a warning note that most likely it is not authentic. It depends on email service providers what exactly will happen with an email that fails the signature test. DomainKeys Identified Mail will also provide you with an added layer of security when you communicate with your business allies, for instance, as they can see for themselves that all the emails that you send are authentic and haven’t been manipulated in the meantime.