It was overtaken, as jvirta says it was cracked, very embarrassingly
It was naive of Canon to think they could make that working, if there's a will there's a way - even if using asymmetric cryptography the private key has to be somewhere in the camera, so it will be found unless using extremely expensive high-security parts.
hmmm i always thought raw is original enough to prove authenticity.
No, if you can de-mosaic it you can re-mosaic it :-) ... But it doesn't matter, it's not difficult today to detect image modifications, a German computer magazine (c't/iX) had a series about it. The only way to fool the detection: Print the tampered original, and re-photograph it in a blurry/shaky way ... but as algorithms evolve also this probably won't work, just as they *might* some day come up with a affordable finger print detector that cannot be easily fooled :-)