Securom checks for DPM in newest version. Safedisc checks for weak sectors. All they did is mix up the game data and weak sectors... No big trick. And they put the safedisc files at the very end of the disc, and it checks for them... which in my opinion is a really lame trick.
Securom is even lamer tho. Only checks DPM, so you can easily make a maxi image and then compress it to 16 kb so it doesnt take up all that HD space, and you got yourself a mini image. God bless windows on the fly compression