DKIM, which stands for DomainKeys Identified Mail, is an authentication system, which hinders email addresses from being spoofed and email content from being manipulated. This is done by adding a digital signature to each email sent from an address under a given domain name. The signature is issued on the basis of a private encryption key that’s available on the outgoing SMTP server and it can be validated by using a public key, which is available in the global Domain Name System. In this way, any message with changed content or a spoofed sender can be recognized by mail service providers. This approach will strengthen your online security significantly and you’ll be sure that any e-mail message sent from a business ally, a banking institution, etc., is authentic. When you send email messages, the recipient will also know for sure that you are indeed the one who has sent them. Any mail that turns out to be fraudulent may either be marked as such or may never end up in the recipient’s mailbox, based on how the particular provider has decided to handle such messages.