4 ms·

Wouldn’t this be trivial to defeat once you know how it works though? Make a bit-for-bit copy, then overwrite track 9 with the new obfuscated lengths.

Dylan16807 6y ago
The same goes for any copy protection. If you understand how it works, you can change the code to bypass it. So it's "trivial" after you do the hard part. The clever thing is that it forces you to do the hard part without special hardware.
- garmaine 6y ago
  Not really. The PSX copy protection, for example, couldn’t be written by standard CD-R writers.
  - Dylan16807 6y ago
    I'm talking about understanding how it works on a code level. You don't need to write the special disk out if you're patching the code, like this article does.
    - garmaine 6y ago
      Yeah but you'll have to hunt for and fix the code wherever it is on every disk, which could be subtly or completely different between applications. "Recalculate track 9" is a simple program that would have worked on any Western Security DRM disk.
      - Dylan16807 6y ago
        You're assuming it's always in track 9 in the same spot. What if it isn't? And what if different applications use slightly different obfuscation? If we're assuming Western Security DRM is always in the same spot using the exact same method, why not compare it against some other type of copy protection that always puts the exact same checking code in the same spot? It would actually be easier to blot out the other type's code with NOPs than to recalculate obfuscated Western Security track-length tables.
MagnumOpus 6y ago
Once you know how it works, you would just overwrite the checks for track 9 with NOPs (or a fancy picture of your cracking team’s logo)...
- caf 6y ago
  Although the GPs suggestion would stand a chance of creating a generic copier for disks protected using this method, rather than having to individually crack each title.
  - Dylan16807 6y ago
    Only if they use the same obfuscation and put the data in the same spot. So it's like any kind of copy protection, you can make a "generic" copier/patcher if and only if a bunch of titles implement it the same way.
megablast 6y ago
Why not just skip the copy protection routines????
djmips 6y ago
Not the Beeb but this copy protection was also used on the Apple II for example which is why we ran with the cases off so we could adjust the speed screw to match track lengths. There was software that would visually feedback the track length so you could get it spot on.

Dylan16807 6y ago

The same goes for any copy protection. If you understand how it works, you can change the code to bypass it. So it's "trivial" after you do the hard part. The clever thing is that it forces you to do the hard part without special hardware.

garmaine 6y ago
Not really. The PSX copy protection, for example, couldn’t be written by standard CD-R writers.
- Dylan16807 6y ago
  I'm talking about understanding how it works on a code level. You don't need to write the special disk out if you're patching the code, like this article does.
  - garmaine 6y ago
    Yeah but you'll have to hunt for and fix the code wherever it is on every disk, which could be subtly or completely different between applications. "Recalculate track 9" is a simple program that would have worked on any Western Security DRM disk.
    - Dylan16807 6y ago
      You're assuming it's always in track 9 in the same spot. What if it isn't? And what if different applications use slightly different obfuscation? If we're assuming Western Security DRM is always in the same spot using the exact same method, why not compare it against some other type of copy protection that always puts the exact same checking code in the same spot? It would actually be easier to blot out the other type's code with NOPs than to recalculate obfuscated Western Security track-length tables.

MagnumOpus 6y ago

Once you know how it works, you would just overwrite the checks for track 9 with NOPs (or a fancy picture of your cracking team’s logo)...

caf 6y ago
Although the GPs suggestion would stand a chance of creating a generic copier for disks protected using this method, rather than having to individually crack each title.
- Dylan16807 6y ago
  Only if they use the same obfuscation and put the data in the same spot. So it's like any kind of copy protection, you can make a "generic" copier/patcher if and only if a bunch of titles implement it the same way.

megablast 6y ago

Why not just skip the copy protection routines????

djmips 6y ago

Not the Beeb but this copy protection was also used on the Apple II for example which is why we ran with the cases off so we could adjust the speed screw to match track lengths. There was software that would visually feedback the track length so you could get it spot on.