Like most computer software, Blizzard's games can be easily copied and distributed over the Internet. Blizzard has taken steps to avoid piracy by designing to restrict access and use of the mode feature of the game. Each time a user logs onto , a server examines the user's version of the game software. If a Blizzard game does not have the latest software upgrades and fixes, the service updates the customer's game before allowing the game to play in mode. With the exception of "Diablo," each authorized version of a Blizzard game comes with a "CD Key." A CD Key is a unique.
