mike_311 wrote in post #18088191
has anyone ever modified a .cr2? it would be a pretty big deal if someone was able to since it could have forensic and investigational data implications. Canon has never publicly published its raw format and the only way to get it would be to reverse engineer it which has yet to be done successfully as far as i know or at least hasn't been published.
Luckless wrote in post #18088309
You mean something like the specs shown here: http://lclevy.free.fr/cr2/
Or editing as described here? https://jabriffa.wordpress.com …writing-camera-raw-files/
Canon does/did have a sort of 'security checksum' that the camera can embed along side the image data, but it is almost never used due to being off by default. However even that is possible to reverse engineer for anyone who truly wants to get at it. You can't keep something a secret if you hand it to someone in a box and let them go poke at it in private.
Interesting bit of discussion...
On the fundamental, low level, I'd say yeah, a RAW processing programmer could "force" changes to RAW data. I'm glad that they don't -- I prefer keeping RAW as a non-destructive format, but hey, I never delved into the field of digital image engineering, so who knows?
So maybe, as suggested, Canon and other "makers" established some security to try to prevent "tinkering"? I don't know, but I'm glad that established RAW processors seem to honor it...
It's interesting, though, that Canon and other makers can and do alter the actual data when a shot is passed through the Analog to Digital processor. This is typical for ISO values, for example -- the sensor collects the "raw" exposure/R/G/B data, and it is passed through the processor, where it is amplified according to the ISO settings, and then saved as the raw data (not compiled RGB pixels)!
That all can certainly spin the brain a bit, but it can be fun to contemplate!