On Thu, Feb 21, 2008 at 06:02:48PM +1100, David Stowe wrote:
> Canon have a "Data Verification Kit" for their pro digital SLRs
Interesting, I took a look at Canon's website they now sell what is
essentially a smart card (OSK-E3). Its about A$750 but it also
works with their new consumer SLR the 450D (about A$1000).
The card does a cryptographic exchange with the SLR and adds signature
to the image file. I don't know if the accompanying image data like
shutter speed is signed. It should you allow you to establish that
your Paradise Parrot picture has not been modfied since it was taken.
This assumes the card and the camera haven't been tampered with. The card
is probably quite tamper resistant as there is big market for this sort
of technology. I'd guess a determined attacker would have much less
trouble tampering with the camera as tamper resistence probably wasn't
an engineering goal for Canon.
You can authenticate time & location - a security company (Qascom) sells
electronics using GPS and SMS to do this. If this was incorporated into a
camera you could verify where & when an image was taken. I'm not sure
how well this works with GPS but Galileo, the European satelite navigation
system schedule to come online in 2013, has features to make it easier.
Incidentally its easy to timestamp digital documents now. For example
suppose you've taken a Night Parrot picture and you don't want to
tell anyone but you want to be able to proof later you were first to
photograph a Night Parrot. You can use a free internet service like
http://www.copyclaim.com/ to get a timestamp for the image without
disclosing the image and this timestamp establishes the image existed
at that point in time.
This underlying methods (asymmetric cryptography) were shiny&new when
I was shown them in the late 70s in an extra-curicular course aimed at
getting year 11&12 students to do tertiary maths. I was interested to
see my nephew was shown the same material and newer stuff like zero
knowledge proofs last year in a similar course
Andrew
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