Why aren't known-plaintext attacks against digital media trivial ?
Shawn K. Quinn
skquinn at speakeasy.net
Thu Oct 8 00:14:16 PDT 2009
On Thu, 2009-10-08 at 05:39 +0000, John Case wrote:
> Let's say I am authoring a video clip for blu-ray. I have a scene
> transition that goes to solid black. Let's further say that the tool I am
> using allows me to insert such "screens" and I define them with hex color
> values ... so I simply say "fill screen with #000000 for 2 seconds".
> Which essentially turns into a display resulting in 1920x1080 pixels of
> that hex code. For 30-60 frames per second.
> Why aren't events like this huge sources of known-plaintext ?
They are. This was how the 40-bit cipher used for DVD's CSS was cracked.
With modern 128-bit ciphers it's a lot harder to crack even with known
plaintext; the MPAA learned their lesson.
Shawn K. Quinn <skquinn at speakeasy.net>
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