Any camera does a huge amount of processing before even giving you a raw file, in most cases. And any algorithm for data reduction like converting true raw sensor output to processed data, say JPG, is somewhat hash like. But not a cryptographic hash, more like a locality sensitive hash. Of course this can be exploited to identify cameras.

Really old Sinar digital backs came with a calibration file unique to the CCD serial, newer cameras have it embedded in their firmware typically. You can also build these calibration files, but the way you apply it will still leave processing "marks" that someone will be able to pick up.