DomainKeys Identified Mail (DKIM) is a validation system used to prove that an e-mail message has been sent by an authorized mail server or person. An e-signature is attached to the email’s header by 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 confirm who actually sent it and if its content has been edited in any way. The essential job of DomainKeys Identified Mail is to block the widespread scam and spam email messages, as it makes it impossible to fake an email address. If an email message is sent from an email address claiming to belong to your bank, for example, but the signature doesn’t match, you will either not receive the email message at all, or you’ll receive it with a warning alert that most probably it is not authentic. It depends on email providers what exactly will happen with an email message which fails the signature test. DomainKeys Identified Mail will also give you an extra layer of protection when you communicate with your business partners, for example, as they can see for themselves that all the messages that you send are authentic and haven’t been modified in the meantime.