Product key

A product key, also known as a software key, serial key or activation key, is a specific software-based key for a computer program. It certifies that the copy of the program is original.

Product keys consist of a series of numbers and/or letters. This sequence is typically entered by the user during the installation of computer software, and is then passed to a verification function in the program. This function manipulates the key sequence according to an algorithm or mathematical formula and attempts to match the results to a set of valid solutions. If they match, the program is activated, permitting its use or unlocking features. With knowledge about the algorithm used, such as that obtained via reverse engineering of the program, it is possible to create programs called keygens that generate these keys for a particular program.