[oppositelock]

You're referring to GCJ-02. From best as I can figure, it adds some form multi-frequency noise to a shifted WGS84 coordinate, but it also seems that different companies are told to use different coefficients for the different noise frequencies, that's how they can tell if you're doing what you're told.

Regardless, it's difficult to work with. If you have a mapping license, you must also take serious precautions never to let the accurate map data leave China, or your Chinese employees are in deep trouble.