In order to Decrypt the encrypted text, you must know what type of encryption it is. Then you work onto decrypting it manually, it will take hours, days or even weeks. Or you can search the google for a tutorial (if there is any), or don't click me a program that does it for you in seconds.
You could ask the makers of the cdkey changer (Or cdkey grabber, but shadowfrench is gone). But you'd have to find that out yourself, I've got no idea who they are.
