keygen.exe is a process registered as a backdoor vulnerability which may be installed for malicious purposes by an attacker allowing access to your computer from remote locations, stealing passwords, Internet banking and personal data.
This process is a security risk and should be removed from your system.
Non-system processes like keygen.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that over time your registry suffers fragmentation and accumulates invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues