Re: Digital Watermarks for copy protection in recent Billbo

["Deranged Mutant" <WlkngOwl@unix.asb.com>]

On 22 Jul 96 at 11:19, Alex F wrote:
[..]
> > Other issues: what if an eavesdropper steals the music or video? It's 
> 
> If they steal it, well, who cares?  If there is something worked out 
> so that they could trace STOLEN (not traded or sold) CDs then fine, 
> arrest them.  Do you really think though that anyone would waste so 
> much time over $8?

Sniffers aren't much effort, and if I sniff your tagged purchases and 
put them out over the net anonymously, they are traced to you.

> > If it uses a credit-card number as (part of) an ID, that's pretty 
> > bad.  Someone can sniff for CC numbers if they know how it's stored.
> 
> Probably not done that way.  My guess is that the disk ID is assigned 
[..]
Probably, but the Billboard article discussed using CC numbers as an 
ID in the online watermarked transactions.  Doesn't mean they were 
correct, of course.

> > The system will have to rely on proprietary tech and security through 
> > obscurity.  Even know how watermarks are stored without understanding 
> > the math, one must be able to somehow garble the sound without 
> > distorting it, but which renders the watermark useless.
> 
> Actually, this would be quite easy.  The "watermark" would be a 
> signal that plays inband, but out of our hearing range during the 
> entire CD.  The human ear can only hear in the 20-20,000 (Hz, KHZ?, 
> whatever) range.  It would be trivial to add a digital ID signal at, 
> say 30,000 or 15 or something like that.  This could then be decoded, 
> if need be.  This seems the easiest and most efficient way.  This 
> could also be defeated with a lot of $$ (and/or a LOT of HD space).  
> If the frequecy is known (it can be found out) it can easily be run 
> through recording studio eqipment that can very effectively isolate 
> the frequency and cut it out.  If you have a LOT of HDD space 
> (digital audio at 2 stereo tracks, not sure of the sampling rate or 
> bit resolution, takes about 20MB of HDD space per minute (2 tracks, 
> good sampling and bit rate) ) you could probably find the freq. 
> fairly easily by isolation and just edit it out, and write the new 
> stuff to a CD-R.  If the signal is purely digital, I would imagine 
> that it might be even easier that if it were an analog signal (?).  
> Someone w/ good equipment (Digital Labs' stuff, or SAW (Software 
> Audio Workshop) would be able to do this w/o much problem.  The 
> question is is the price/effort worth it?  In quantity maybe.  On an 
> individual basis, only if you already happen to have the erquipment.

For someone in the misuc counterfit business, the equipment is 
probably not that expensive.  It's innocuous enough (recording and 
editing equipment) that it wouldn't draw suspicion.

AFAIK, most "bootlegging" is of unreleased concerts or out-takes. 
Digital watermarks would be of little use.

> I have a suspiscion that this type of thing will not really come to 
> any kind of fruition due to not only the ability to defeat this, but 
> mainly due to things like buying at a garage sale, etc.  If it did, 

I think it's intended for tagging online transactions.  You connect 
to a company's site and download the latest album or single by some 
band, presumably with the rights to transfer that to a tape for 
personal use.

If this becomes a predominant way of buying music or movies in an
eventual future (when most people on the planet are wired) and 
anonymous purchases disappear (I doubt it) as well as radio 
broadcasts (another loophole) die out (quite doubtful as well).

Of course you have to be foolish to pirate under such a system using
your own name.



Rob
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