Battle.net is an Internet-based online gaming, social networking, digital distribution, and digital rights management platform developed by Blizzard Entertainment. Platform launched on December 31, 1996, along side the release of Blizzard's action-role-playing video game Diablo. Battle.net was the first online gaming service incorporated directly into the games that make use of it.
Log in to Battle.net
Locate "Add a Game Key" option
Enter your key code