Ben Laurie wrote: > The other obvious weakness in such a scheme is that the player can > be modified to ignore the result of the check - rather like > defeating dongles, which have yet to exhibit any noticable > resistance to crackers.
I think though that that weakness is more workablee -- for example playstations can be "chipped" to work from copies of CDs, however probably the proportion of the market willing to make hardware modifications is sufficiently low that the copying rate is not a significant financial loss to the distributor (especially after adjusting for people who wouldn't have bought the work anyway, which is the group most likely to make the modification (students with low budgets etc)). Things which can be defeated in software or firmware upgrades only are for more fragile, and subject to changing user demographics, more internet aware and connected users, increasing scale of file-sharing networks; whereas devices needing hardware modifications have non-zero reproduction costs, and risk of damaging expensive equipment in the operation. On Wed, Oct 17, 2001 at 10:23:03AM +0100, Ben Laurie wrote: > Adam Back wrote: > > [...why copymarks don't work...] > > [...] > It seems to me that putting the details of the purchaser in plaintext on > the beginning of the file and making it illegal to remove it is as good > a protection as you are ever going to get - but that would ruin a whole > bunch of business plans, so I guess no "expert" is going to admit that. It may be more to do with attempts to qualify under legal provisions of DMCA to construct something which is (legally) arguable qualifying as a system intended to prevent copying, so they can sue people who by-pass it. Another argument I've heard for making dumb proprietary schemes is that they ened them to be proprietary so they can make onerous conditions part of the licensing agreement, and sue anyone who makes devices or software without licensing their broken technology from them. In effect that it's utterly broken doesn't matter -- that it's claimable as an "original" work under patent law matters. > In short, the agenda, it seems to me, is the business plans of > companies in the watermarking business. That too is doubtless part of the problem. IBM's cryptolopes lending credibility by brand recognition to related technologically broken efforts such as InterTrust and other watermark related business plan startups "digi-boxes" and the like. SDMI was another broken attempt. > No more, no less. I'm amazed the media moguls are willing to waste > so much of their time and money on it. It could be that the only thing keeping the InterTrust types in business is the patentability and DMCA qualifying legal arguments above. Technologically they are all systemically broken. There may be an element of technological naivete on the part of MPAA RIAA too though, perhaps decision makers were genuinely confused to start with, and crypto-box outfits will have incentives to exaggerage the technological properties of their systems to their customers, the RIAA, DMCA etc. Adam --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]