Sunnyvale, Calif.--Yahoo! on Monday announced it has implemented DomainKeys, its authentication technology solution, within its servers as part of its e-mail service. DomainKeys, which has been described by e-mail industry experts as a more complex authentication solution than both Microsoft's Sender ID and AOL-endorsed SPF, validates an e-mail's origin through encryption in message headers and technology that matches it with the Internet's DNS (Domain Name System) for decryption. The three authentication protocols were all designed to foil spammers and phishers. Phishing, or online identity theft, has grown rapidly in the past several months. Earthlink and Google have both pledged support for DomainKeys. All of the authentication processes still need approval from the IETF (Internet Engineering Task Force), which is reviewing the three proposals.