CD key is also referred to as product key. CD key is generally a serial key that is used to activate programs and games. CD key is usually generated by software which is included together with the programs or games. CD key is used to verify that the application is not an illegal copy. CD keys are generally unique and one CD key can be only used by one person. CD keys consist of series of number
. and/or letters and are typically entered while performing an installation of computer application.