Hamlet...

> The kind of security key you are advocating doesn't give you any
> protection from falsified or manipulated data from the source.

Sure! There's no such thing as absolute protection. But it would at least
prove that some image was originally produced by ESA or Nasa.

Aerik....

> Another reason there aren't security key's, and Phil goes over this too
> (but not for this reason) is that it would go against the spirit of the
> NASA version of an open information act, which declares that after one
> year, all the data from a particular project on Hubble (or whatever
> instrument) is open business to the public. Watermarking 'original'
> images would be serious trouble.

I'm not talking about a watermark.

Think Open Source software or GPL GNU licenses.

Many of those software projects have SHA to protect their work.

A space image could be compared to a piece of software...as you say
it often goes through a long development life cycle...passing through
many pieces of software and human hands. So why not protect that
work just in case someone alters the image and uses it to make a
false claim. Why not have the capability to verify the data with the
source that produced it ?

~~~

FITS....Obviously a usefull format...but no SHA's!

WITS....secure, yes...but this is for inter agency communications.

I'm talking about a way for a scientist/researcher/member of the public
to confirm an image. For example.


Scenario: An "independent researcher" says that an image was "leaked"
to him from ESA. He uses this image to claim that it shows an artifact
predicted to appear in Islam (for example). The image catches on and
starts causing a serous religious disruption. ESA claims it never released
the image. Without a key to verify the image against, nothing can be
proven.


Scenario: A group produces a satellite image of the Iran/Iraq border
"proving" that the Iranians have started an invasion. The satellite
administrator denies that the image is from their sat and has been doctored
for political purposes. If the sat administrator could produce
a key that he can prove was generated before the event (this assumes
that one of their images was actually used but doctored) then it
can be proved that the image is a fake. An unnecessary international
crisis is avoided :-)

Actually maybe the spy sats do this all the time.


Snarkophilus...

Yes....I saw it in the Mars Global Surveyor (RIP :-( ....) specs. It has error
correction/compression. I don't think it could be used to prove the
worth of an image though (unless any MGS MOC experts say otherwise).

I was actually looking into this after claims in the "anomalist" community
that NASA were "airbrushing" images. I was attempting to compare
their "examples of tampering" with the original raw data...and checking
the error correction.

DJBarney