A method and system is directed to providing authentication of a message, such as email, and the like, by combining Public Key encryption and the Internet Domain Name System (the "DNS"). A domain owner may validate that an email originates from an authorized sender within their domain by using a private key component to digitally sign email outbound from its domain. Employing a public key component, along with a selector, an email recipient may check the validity of the signature, and thus determine that the email originated from a sender authorized by the domain owner. In one embodiment, the public key component used to verify an email signature may be "advertised" or otherwise made available via a TXT record in the DNS.