Keygen

A license or product key generator (usually stylized as keygen) is either a computer program that generates a licensing key, serial number, or some other registration information necessary to activate for use a software application, or a program that generates public-key data for cryptographic application such as the ssh-keygen utility. Most of the anti-virus programs will detect it as a trojan because it patches other programs (assembly or registry entries). Any application that isn’t signed by a reputable author and attempts to modify the structure of other applications is usually classified as ‘potentially malicious’. It may be a false positive (meaning it’s not actually a virus, but the anti-virus thinks it is) or it may actually be malicious. Keygens are often accompanied by Chiptune-music.