If your antivirus or scanner gives you an alert indicating that the keygen is a virus. It's a false alarm!
"Some anti-virus programs detect false positives when .exe's are PEcompacted and even when not. BTW, false positive is often called heuristic by AV scanners (ie:- not sure if it is or not). The majority of keygen/crack release groups are actually very professional and would never tarnish their own reputation."