The HDDVD Processing Key and the colouring revolt
(Please read “What Colour are your bits?” and its followup. They make a great explanation for computer scientists of when a number isn’t a number.)
I’m sure by now everyone has heard of that famous integer and its hex representation that’s been all over digg. It’s the key that can be used to decrypt just about all HD-DVD discs produced before the leak with the help of a program like BackupHDDVD. There, now I can’t post the number.
The number isn’t copyrighted. It’ll probably be posted one day as a MD5 sum of a downloadable chunk of data and things’ll be peachy. No, I’d be in trouble because I’ve given valuable context to the integer. It’s not inherently clear what magic it holds. Without being told what it can do it’s just a number, now it might be a part of a circumvention device. I gave these bits context and colour.
The same thing happened to Phil Carmody’s illegal prime. It’s a notable number because it’s big, but it’s far more known because it can be manipulated pretty easily into giving up DeCSS. That’s the biggest source of its colour and why it might’ve been hunted down if the DVD CCA didn’t give up. The digg revolt’s second biggest accomplishment was adding more colour to the hex key, I’m hoping its biggest accomplishment will be putting it and BackupHDDVD on the same path of acceptance as DeCSS.
Now, just for fun, here’s how to fiddle with the illegal prime to get it to reveal the DeCSS code.
Jamie McCarthy (probably the one at http://mccarthy.vg/) has written a perl script to decode these illegal integers. Unfortunately it scrapes a no longer existent webpage. I’ve modified it to take input from STDIN.
- Go to the illegal primes page on Wikipedia.
- Copy and paste one of the primes into a text file, maybe name it bob.
- cat bob | perl illegalprime.pl | gunzip
