Keygen
A key generator is a computer program that generates a product licensing key, such as a serial number, necessary to activate for use of a software application. Keygens may be legitimately distributed by software manufacturers for licensing software in commercial environments where software has been licensed in bulk for an entire site or enterprise, or they may be developed and distributed illegitimately in circumstances of copyright infringement or software piracy. Illegitimate key generators are typically programmed and distributed by software crackers in the warez... Wikipedia