actionscript for protecting swf?

Hey... I know theres a actionscript to do this but i'm not 100% sure what it is. Basicly if the swf is downloaded or put somewhere else, it gets taken to a page that says something like STOLEN, etc and if it is hosten on the correct site, it continues the movie. I want to do this to my site and anyone know the actionscript for it?

Thanks in advance :)

lets say you load your movie to
http://www.kallok.com/flash/movie.swf
then the actionscript you can use in the first frame is

if (_url != "http://www.kallok.com/flash/movie.swf"){
stop();
getURL("http://www.kallok.com/stolen.html");
}

Now if you move your movies around you might want to use substring on your _url just to check to see if its somewhere in http://www.kallok.com etc