[..] : > 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. HDD space is -cheap- 2 gig drives sell voor 350 usd in Holland, most music cd's contain 70 minutes of recording thus -at your 20 Mb per minute rate- would require 1.4 gigs. So basicly 'CD-pirates' need to buy a PC with a 2 gig HDD and a CD-R, a 'one-off' investment of say 5000 usd; besides their normal cd maunfacturing, packaging and transportation, those additional 5000 usd are peanuts compared to the total investment for pirating CD's. : 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. : 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, : only MASS market piraters would be investigated. (Another example of : a law creating it's own violators. Don't make the law, there won't : be mass piratingof "clean CDs" bEST Regards, -- -AJ-