Canon and I imagine the other high end camera companies have a software application that allows the image certified as unchanged. Its good enough to meet court evidence rules. Don't know if this is what TRAINS is looking for though.

The way these thing usually work is to go though the image file and add up the ones and zeros and then embed the "check sum" at some point in the file where it can't be easily discovered. Usually there is some complicated formula that subtracts some value and then divides the remainder or some such to create the check sum. If anyone edits or changes the image, the check sum of the edited photo will not equal the value of the saved check sum showing the photo has been edited.

Well that is interesting. So if that is the case, there is indeed a sort of digital fingerprint embedded in the original RAW file that distinguishes the orginal from copies, as I speculated about back in post #27. If this is the case, then there is a positive method of proving that the photo contest submissions are the original RAW files straight from the camera.

Yesterday, I emailed two differenct offices of TRAINS asking the general question developed here about how they will enforece the rule requiring contest entrants submit only original RAW files. I am waiting for their response.

RTK

No, there isn't.

Canon's "Data Verification Kit" is an add-on product, which includes a special memory card which supports real-time encryption of certain key information, a card reader for that card, and associated software. It's pricey, and only supported by certain Canon digital SLRs (for example, none of the Rebel line is supported). While I've never personally used the kit, I believe its most common use is actually with jpegs, not unprocessed RAW images, as RAW images have to be, well, processed - ie modified - before you can do anything meaningful with them.

In any case, it's hardly a practical solution for a TRAINS type photo contest.

Scott