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[dvd-discuss] Re: DVD Descrambling Code Not a Trade Secret

On Sat, 24 Jan 2004 13:26:52 -0800, John Schulien <schulien@speakeasy.net> writes:

> Probably HDVD, or whatever they call high definition DVDs.  Besides
> giving the MPAA the chance to reissue their entire catalog in the
> new format and suck in money like a vacuum cleaner, 

> it would also give them the opportunity to replace the failed DRM
> system as part of the new format.

The DVD digital control technology (I refuse to use the phrase 'DRM'.)
was a reasonable design. The hopeless flaw was that their 'one-way
hash function' wasn't very one-way and could be inverted in 2^24
work. Had it been MD5 or SHA-1, things would have been much
different. Without that flaw, they could just revoke all software keys
that got disclosed or reverse-engineered. That would result in a
strong darwinian selection on software decoders to obfuscate the keys
to hell and back.

The 40 bit keys are bruteforcable, but thats still some effort to
obtain a key that can be revoked on future dvd's.