Noun
English Wikipedia has an article on:keygenWikipedia
keygen (plural keygens)
(computing) A small program used to generate a license key used to unlock a trial version of software illegitimately.
Screenshot of Keygen by MESMERiZE * Keygens - Keygen software are tools that replicate the registration/activation process of a genuine software product and generate the necessary keys to activate the software. Source: Internet