Hi,
If you liked this presentation:
http://www.elcomsoft.com/presentations/Forging_Canon_Original_Decision_Data.pdf
maybe you'll be interested by this code:
https://github.com/lclevy/odd_verify
Thanks to Magic Lantern project to let me extract keys from memory!
Laurent
http://lclevy.free.fr/cr2/
Sorry for holding up your post :)
The style of jpge coding could tell whether the jpg file is created by camera or a PC software