Battle.net Authenticator is an optional tool that offers an extra layer of security to help prevent unauthorized people from breaking into your Battle.net account (needed to play Blizzard games like Starcraft 2 and World of Warcraft).
With this tool, starting a session with your Battle.net account will not only require your regular password but also a single-use code that will be randomly generated by Battle.net Authenticator. This way, you can be sure no one else can access your Battle.net account.
Battle.net Authenticator is a very interesting tool for regular users of Battle.net which gives you the opportunity to further protect yourself from this particular kind of hacking.
