A CD key is a series of numbers and letters that allow a software purchaser to activate and use the software. CD keys for "Freedom Fighters", as well as most other games, are typically found inside the game's jewel case. The length of the key varies by software title.
In order to receive a valid CD key for "Freedom Fighters", a 2003 first-person shooter game available for a variety of platforms, one must purchase the game from a distributor. CD keys are often required for software in an effort to prevent software piracy and allow the software manufacturer to maintain control of the product.