Blizzard Entertainment today announced that an optional extra layer of security have been introduced to World of Warcraft. Designed to attach to a keychain, the lightweight and waterproof Blizzard Authenticator is an electronic device that generates a six-digit security code at the press of a button. This code is unique, valid only once, and active for a limited time; it must be provided along with the account name and password when signing in to the World of Warcraft account linked to it. Press 'read more' for details.