At 3:32 PM -0500 12/5/96, Nelson Minar wrote:
Ah, the age-old question. This is the same question as "is there a way for me to show a web page to someone and not let them copy it?", "is there a way I can loan someone my CD and not let them copy it?", etc. If you have control of the viewer, the answer is trivially yes. If you don't, then it's not.
Digital watermarks / fingerprints are one alternative - if someone steals it, you can at least prove whom it was stolen from. Or you ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ might be able to exploit some of the structure of VRML to show people an avatar but not ever reveal the *whole* thing for copying. But in general, this sort of problem seems to demand a social solution (intellectual property law), not technical.
Yes, you can perhaps show whom it was stolen _from_, i.e., the creator, but not _who_ stole it. Even in the case where each end recipient receives a uniquely watermarked or marked image, e.g., where N different instances of the work are instantiated, there are ways to obscure the source of the theft (or leak, when one is using such techniques to detect leaks of confidential information, a la the famous "canary traps"). To whit, M recipients of the work can compare their copies and remove or modify the bits which don't match up. This then yields only a "collusion set" the original creator can narrow things down to. Enough to cast doubt on the M recipients, but probably not enough to "probabalistically convict" them of a crime, unless the crime is "conspiracy." An interesting question. As Nelson notes, not something with easy technical solutions. --Tim May Just say "No" to "Big Brother Inside" We got computers, we're tapping phone lines, I know that that ain't allowed. ---------:---------:---------:---------:---------:---------:---------:---- Timothy C. May | Crypto Anarchy: encryption, digital money, tcmay@got.net 408-728-0152 | anonymous networks, digital pseudonyms, zero W.A.S.T.E.: Corralitos, CA | knowledge, reputations, information markets, Higher Power: 2^1398269 | black markets, collapse of governments. "National borders aren't even speed bumps on the information superhighway."