DKIM, which stands for DomainKeys Identified Mail, is an email authentication system, which prevents email addresses from being forged and email content from being modified. This is done by attaching an e-signature to every email message sent from an address under a particular domain. The signature is created based on a private encryption key that’s available on the outgoing SMTP mail server and it can be validated with a public key, which is available in the global DNS database. Thus, any message with modified content or a forged sender can be spotted by email providers. This approach will strengthen your online security considerably and you’ll be sure that any e-mail sent from a business ally, a banking institution, etc., is authentic. When you send out email messages, the recipient will also know for sure that you are indeed the one who has sent them. Any email that turns out to be bogus may either be marked as such or may never end up in the recipient’s inbox, depending on how the particular provider has chosen to cope with such emails.