Basically, the problem decomposes into two areas:
1)Can you protect the information from being distributed.
2)Can you mark the information such that if it is distributed, you can
track the one who distributed it.
In each area one must consider audio, video, text, and images.
Area 1:
If the content provider encrypts the information with a user's public
key and provides a viewer that decrypts the information using the
user's private key, then ostensibly the information will be somewhat
secure if there is no way to save a deciphered version of the
information from the viewer.
Of course, other programs can grab the information off whatever output device
is being used. Image grabs are trivial to do, video grabs and audio
grabs are somewhat harder. A text grab would take some effort and
some OCR, but is possible. However, one can imagine stumbling blocks
being put in place that would deter some of these, e.g. ignore certain
X events etc.
Area 2:
Well, how do you protect information if someone can grab it? Chiefly,
I'm looking to see if anyone has investigated schemes to sign an
image/video/audio with the user's key that are not perceptible and
can't be removed from the information.
If anybody knows of people working on this problem, of papers that
exist, etc. Please give me some pointers to the info. Also, if
anyone knows of products that are being developed/exist in Area 1, I'd
be interested in this information also. (are the commercial web
browser people looking at this?)
Thanks,
David Berger
Graduate Student Researcher
University of California at Berkeley