jducoeur

To the extent that noise can be accurately subtracted, even on a probabilistic basis, camera makers already have reason to do that, within the limits of the camera's ability. After all, noise is by definition stuff you didn't want in your picture to begin with. For example, some cameras will already take a pre-exposure with the shutter closed, and subtract off the artifacts from the dark frame (this won't help with all of the non-random noise source in a digital camera, but it's noticeable under some conditions).

I don't think something as simple as a deterministic transform would avoid leaving a fingerprint. At best you'd increase the computational power needed to match the fingerprint (rotating and cropping the picture would be good ways to do that also). That way lies an arms race.