DVD Drives Defeat Cactus Data Shield

jsepeta sends in a story about Cactus Data Shield, one of the schemes to be used for copy-protecting compact discs. A reporter for TechTV notes that DVD drives see right through the disc corruption that Cactus uses to supposedly prevent those CDs from being ripped.

Comments

A theory if you will

[HongPong]

I strongly suspect something other than the usual theory of CD-ripping protection is going on here (inserting checksum-foiling bits or some such). These guys switched from Wintels (a lot of Dell-wintels to be even more generic) with CD players to DVD players, controlled by different automatic Windows procedures. No mention is really made of the difference in how DVD players *under windows* play regular CDs differently anyhow.

It seems to me this is just one of those CDAutoStart things that Windows responds to in particular.

I got tipped off to this by when they mention "Track 1" never plays. I BET they didn't notice the total track count go up by one, as the Windows software talking to the DVD player parses its error-handling differently (correctly), and the result is like putting a PC hybrid CD in a Mac. In fact i strongly expect this Cactus lockout thing would not work on a Mac by default, and very very likely Linux/*nix as well. The tracks would appear as normal, though possibly not that first track, because its header DOES get lost in the scrambling, maybe.

Perhaps this is hogwash, but I've heard about Macs seeing through similar schemes before. I think that these TechTV guys sort of percolated through the truth of older reports to home users that are kinda savvy but don't like leaving their Gates Paradigm Computing, thus only the windows DVD stuff, no mention of other platforms at all.

On the other hand, if this is not unique to Windows (I wonder about Mac DVD players) then maybe that program has low-level drivers which affect how the CD drive does checksums, but DVD players do differently anyway.

Yeah, another victory for the Fair Use groups, as the people designing this have their asses backwards because they're counting on all computer users (mass 37331 pirates) to be Windows computers. OOPS...

Universal, i will scout for your discs, and as a Mac user of self-proclaimed badassary, "hack" via insertion your CD, rip, burn and mail to your well-tanned California ass.... Mwahaaha... All right enough fevered fantasies of geek revenge... back to work...

if you can listen to it, you can rip it

[markj02]

I don't understand why the record labels are expending so much effort and political capital on this. I mean, you can rip any CD by just connecting to the analog audio output. Sure, it's 1x, but you can do it while you listen to the CD or automate it with an audio jukebox. Given that MP3 is a bit worse than CD anyway, any theoretical loss in quality doesn't matter (and a bit of analog degradation might do the CD recording some good anyway). And once it's in MP3 format, you can send it to the whole world.

Not even watermarking is going to see them out of this. Watermarks can be removed anyway, and even if they succeed in a lunatic scheme to require that every computer audio board have some kind of watermark detection circuit, A/D and D/A converters that are fast enough and good enough are cheap, widely available, and easily hooked up to a PC.

Are the record labels just clueless or is there some other diabolical plan in the wings?

Perfect copy protection IS possible!

[Tsar]

I have a CD with the only truly unbreakable copy protection I've yet tested. The publisher accomplished it by omitting the CD's the metal layer and, apparently, the dye layer as well. The result is a disc which is almost completely transparent. Sadly, the disc is unplayable on any of my equipment, DVD-ROM drive included. Perhaps the publisher anticipated that problem, and that's why he published it without a label, and distributed it for free with spindles of CD-R's.

All kidding aside— here is a formula that might be useful to publishers of digital data:

Rc = ( Cm + Ce + ( Ca * Pa ) - Cp ) * Vd

where

Rc = Risk of the data being illegally copied
Cm = Cost of recordable media
Ce = Cost of effort needed for duplication
Ca = Cost of being apprehended
Pa = Probability of apprehension
Cp = Cost of purchasing data
Vd = Value of the data

If L > 0, the data will be copied.

A publisher can control the level of his data's protection only to the degree that he can control these variables.

• Cm cannot be kept artificially high, due to market forces to the contrary;
• Ce continues to drop, as coding ingenuity continues to outstrip copy prevention standards almost as quickly as they are developed;
• Ca is relatively low for the end user, since it usually only involves paying for software you had anyway; and
• Pa is low because the crime is widespread and social costs are low, so enforcement at the end user level is minimal.

This leaves a publisher of digital data with two variables he can control: the data's cost and its value. This provides two options for perfect copy protection:

• make the product free, or
• make the product worthless.

Since neither option would be attractive to most publishers, it would appear that widespread copyright violations (and violators) will be with us for a long, long time.

Good for music trading after all?

[jmd!]

By making it slightly harder to turn your CD into mp3/ogg's, by the techniques described above (Macs, binary imaging, then spliting with Cool Edit, etc), groups will end up doing the releasing, like in the warez scene. This will ensure a more organized (complete cd's, as soon as the CD is release), high quality (decent hardware used to extract the audio) music album releases.

The only thing hurting the warez scene is games being so friggin big nowadays... multiple CDs, etc. You can't run bladeenc, or oggenc on a game.

Maybe DVD-Audio will help combat music piracy, but that's a bit off.