Sciencemadness Discussion Board - Chemical 'hacking' of self-destructing DVDs

Chemical 'hacking' of self-destructing DVDs

I am a fish - 16-6-2003 at 12:17

Chemistry has many uses. Until now, I didn't think that copyright theft was one of them...

Flexplay Technologies has introduced a time limited DVD that only functions within 48 hours of it being removed from its airtight packaging. After this time, the disc turns black (from its original red colour) and can no longer be played.

Disney is planning to sell cut price DVDs limited with this technology. Presumably, other companies could follow suit. So how do these disks work and how can they be 'hacked' to prevent them from decaying?

Presumably something in the air is initiating the decay reaction. This is probably oxygen, but I suppose it could be carbon dioxide or water vapour. According to New Scientist's Feedback column, the lifetime is increased by keeping the disk in an airtight box in a refrigerator (nice separation of variables). However this is obviously not good enough.

Perhaps a powerful oxygen scrubbing agent such as sodium dithionite could somehow be used as a preservative.

What do other people think?

Organikum - 16-6-2003 at 12:22

Wouldn´t it be easier just to rip the disk?

Blind Angel - 16-6-2003 at 12:30

Sometime the simplest way is the best

If it can be played in DVD player for TV it will be too for Computer DVD...

Organikum - 16-6-2003 at 13:18

Actually if I had to design such a selfdestructing disk I would make it complete selfcontained - no oxygen or else needed, triggered by the light of the laser at first use a avalanche reaction which would cause the disk virtually to blacken from one moment to the other after some days. Keeping in the freezer might prolong the process - but who really minds?

I have a project in mind for some time now: A universal raw-reader for optical media.

It´s a plain electromechanical device doing zero decoding only for to read every single bit on a optical disk. The use of a higher quality laser and optics as in consumer devices should make this possible - regarding the computing power of nowadays PCs the actual decoding should be merely a question of time.
The device should not even try to folow tracks but read the data in overlapping pieces of surface area (0,1mm*0,1mm for example) the first steps of putting pieces together could be made by a graphics software this way, by Fourier transformations also a sound/music software could be used. Leaving the sequential data thinking for patterns. Never forget modern harddisks don´t read single bits - they read wavepatterns and determine probabilities. No shit. True.

Blind Angel - 16-6-2003 at 14:03

GRC (Canadian FBI) has some machine who look like this, it can read broken CD and part of cd...
BTW, it would be the laser because in the text it said that it's decompose itselft in 48 hours even if not played...

I am a fish - 16-6-2003 at 14:33

Quote:

Originally posted by Organikum
Wouldn´t it be easier just to rip the disk?

THAT'S CHEATING :mad:

Plus, a permanent chemical way of preserving the disks could be a lot cheaper than buying a writable DVD.

Blind Angel - 16-6-2003 at 19:15

Maybe a transparent plastic coating like saran wrap glued under vacuum very thin... but it would need to not be scratched...

Iv4 - 18-6-2003 at 06:33

Well a blank DVD costs what 1E in single?That's cheaper than the chemicals and if you'r making copy's....

Anyways does anyone have access to these so they could be placed in gas chambers to see what it reacts to?

Blind Angel - 18-6-2003 at 07:13

blank cd cost ~1$. blank dvd cost ~15-35$

Iv4 - 19-6-2003 at 02:24

Not to insult you or so but I bought a double DVd(maid in manhaten and two weeks notice)for about 2 US.

Blind Angel - 19-6-2003 at 08:34

Not insulting, that simply mean that DVD are costier here

Mumbles - 19-6-2003 at 09:32

Blank DVD's cost less than a dollar a piece. Trust me, I know. I have a DVD burner sitting right next to me. Even the good ones, useful for copying other things I really shouldn't be. Now granted Blank DVD's can still go up into the $20's and even $30's. These are generally Authoring DVD's, or companies who arn't focusing on blank discs. All you need is General Purpose DVD's. Besides Authoring DVD burners are a little on the pricey side, last time I checked. This is at least in the US. I don't know about costs in other countries. Most companies will ship all over the world, so I don't know how much of a factor it really is.

I think i know the problem, the answer avades me

Darkfire - 20-6-2003 at 18:20

Well this is my theory,

The disc should be comprised of an alloy whos state can change from crystaline to anamorphose soilds. This is the way cd-rw's work, the heat of the laser changes the soilds state.

The different states of the 'alloy' will reflect the reading laser at diferent speeds thus causing the laser to get its 1's and 0's.

This leads me to my hypothosis which is, A chemical in the air, likely oxygen shifts the state of the 'alloy' the dvd is made of, after a certain time of exposer the entire dvd is in one physical state meaning it cant work, or the oxygen bonds to a chemical on or in the dvd to form a blanket and will only reflect at one speed again meaning it cant work.

What do you guys think?

Iv4 - 21-6-2003 at 01:42

Probably something like that.Here(south asia-not using a good proxy so please pardon being vague)a dvd burner i about 200 amarican.

I know it's been awhile but I had a thought on this.Th thing uses hemoglobin.

My theory goes like this.Unlike most CD's that have a molded alamuniam surface CD-R's(and RW's)use a dye that changes it's opacity with heat(here's a link).I think that the dye used could be hemoglobin.Well oxyhemoglobin.Im prety sure(not completly)that the hemoglobin/oxy-hemoglobin reaction would be excelelrated by the heat from a laser.Come to think of it it could be made from a master CD where the dots are diferent from the plains.This way one could adiminster oxygen.

Now this being in polymer would slow to about this CD's life span.So all the heoglobin is oxydized.Any credit here?

[Edited on 7-7-2003 by Iv4]

chemoleo - 26-3-2005 at 13:24

I just wondered, wouldnt it be easiest to simply spray the Disc with a fine layer of clear varnish? Sure, it'd need some experimenting, but I am sure this could work, to protect the disc from air.
Ouch. Disney won't be delighted to hear this

Kanem - 26-3-2005 at 16:15

HERE they say how it works:

"The secret to Flexplay discs is an extra layer added to a standard DVD structure. This specialized layer includes a chemical compound that readily combines with oxygen in the atmosphere to form a new chemical compound.

While the original chemical compound is transparent, the new chemical compound is opaque. When the layer is transparent, the laser passes straight through to the reflective layers, reading the DVD as it normally would. When the layer is opaque, the laser can't make it to the inner reflective layer, so the disc is effectively blank to the DVD player. [...] The particular chemicals are balanced so that the reaction proceeds very slowly at first, during the "rental period," and then speeds up."

Kanem

neutrino - 26-3-2005 at 16:20

Do those machines which are designed to remove scratches from CDs work by actually polishing off a layer of plastic? If so, it would be trivial to ‘fix’ a CD: just keep polishing until the black is gone.

cyclonite4 - 27-3-2005 at 04:47

I second that. Why go to all the bother of preserving the disc when you can remove the problem.

Still, ripping is the best way, cheating or not.

Over here in Australia, DVDs were initially expensive, but have dropped to a fair price. Single DVDs are roughly +- $4AUS, but when bought in bulk (which I do), they can cost between $1-2 each, or maybe less. :cool:

Saerynide - 27-3-2005 at 04:47

Or just sand it off, which is faster, then put it into the polishing machine

cyclonite4 - 27-3-2005 at 04:56

Sand it off?
You'll probably crack the disc.

Although that reminds me, one of my uncles (freelance mechanic

), uses a buffing wheel to remove scratches from his CDs. I was actually suprised it works.

Marvin - 27-3-2005 at 05:53

From the description it forms part of the bonding of a dual layer disk, its not an extra coating on the outside. Sanding or polishing until the black goes away would destroy the middle data layer.

sparkgap - 27-3-2005 at 08:38

If you guys are planning to sand them off, you may have to consider how fine the sandpaper would be. Still, I think silica is too abrasive to use for such a fragile disc.

sparky (^_^)

P.S. Why not just try to figure out what they put in those disks? Aren't we chemists or something?

Saerynide - 28-3-2005 at 06:48

I didnt mean sand paper literally. I meant wet/dry paper (silicon carbide paper used for finishing jewelry). The finest grits will bring metal to a mirror shine

cyclonite4 - 28-3-2005 at 07:15

I was thinking Marvin was right for a sec, but the layer must be external in order to react with oxygen.

Use something finer.... like a wet cloth.

Kanem - 28-3-2005 at 10:41

Why?
Are you sure that Makrolon isn't permeable for gases?
I think some polycarbonates are...

And what about an airtight coating for the disc? That would probably render it unreadable...

Or oxidizing the organic stuff with something else than oxigen, so that it stays clear?

Kanem

enima - 28-3-2005 at 10:44

Quote:

Originally posted by I am a fish

Quote:

Originally posted by Organikum
Wouldn´t it be easier just to rip the disk?

THAT'S CHEATING :mad:

Plus, a permanent chemical way of preserving the disks could be a lot cheaper than buying a writable DVD.

Actually in the long term a 50$ dvd writer is going to work out to be cheaper than buying chemicals for all the dvds. IMO chemically 'preserving' the disk is a big waste of time.

Marvin - 28-3-2005 at 17:22

Mr Fish was talking about a writable DVD disc, not a drive.

The amount of dye in a protected layer is miniscule, so a chemical treatment could have a negligable cost.

Best available infomation says the oxygen sensitive dye is leuco-methylene blue with some polyhydroxy aromatics to prevent photochemical bleaching. The key here is that atmospheric oxygen oxidises the molecule, forming a delocalised link between the two benzene rings. The longer the delocalisation, the longer the wavelength it can absorb at. The -N= of the oxidised form is the problem and I'm wondering about a methylating agent. Depends largely what we can get to the layer. The page thats telling us its oxygen activated is the same page thats telling us its part of the resin that bonds the two layers of a dual layer disk together.

If it was possible to polish off the protective layer, somehow I think they would have spotted that flaw by now. They are being sold, so if someone inside the US wants to buy one and report back

Of course under the DCMA and some international laws this conversation itself may be illegal.

trilobite - 28-3-2005 at 18:19

I guess that this technology has been patented.

IrC - 28-3-2005 at 23:31

"this conversation itself may be illegal"

Does this mean free speech is dead, that greedy corporations supercede the first amendment? If so, to hell with their laws.

A: a chemical reaction that leaches out the opaque layer?

B: a chemical reaction that converts the opaque chemical to a non-oxidizing clear product?

C: replace the laser in the DVD drive with a rapidly pulsed YAG?

sparkgap - 29-3-2005 at 02:20

Saerynide, I was thinking silica is bad enough, but carborundum paper is not something to use on polycarbonate discs.

After some research, I have confirmed Kanem's guess that polycarbonate is gas permeable. See here and here.

A reaction that leaches out the opaque layer may render the disc unreadable as well, I think. And how will you source out a YAG laser?

sparky (^_^)

cyclonite4 - 29-3-2005 at 02:33

Even if IrC's methods don't work, the philosophy is right.