Blizzard Entertainment, the company behind Warcraft, Starcraft and Diablo, today informed customers that their internal security network had been breached.

The company doesn't believe that financial information has been compromised but other data including email addresses for all non-China players and scrambled passwords were taken. The company believes it will be extraordinarily difficult for hackers to break into actual accounts, but is recommending that all users change their passwords.

Blizzard does offer the Battle.net Mobile Authenticator [App Store], an iPhone app that dynamically generates a new six-digit code every minute. Users can't log into any Battle.net account -- either through a game or on a website -- without the code. It virtually eliminates unauthorized access to the Battle.net account and it is recommended for all Battle.net accountholders.

Here is the letter from Blizzard CEO Mike Morhaime: