CD-reading for random keys

Sonic Purity sonicpty at sirius.com
Sat Mar 23 00:07:27 PST 1996


In article <4i91h4$lp5 at nero.omega.co.nz>, bruce at omega.co.nz wrote:

>>Doe anyone know where sample code exists to enable one to read the digital
>>stream from an audio CD? <edit>
>>crypto system.  You merely start reading at a specific spot, tossing away
>>bytes using a reproducable random number generator, then permuting
>>those to form a XOR one time key of any length you want.
>
>The "entropy" or randomness of audio data is LOW. That's why audio compresses
>so well. However, the idea of keeping a one-time key on CD-ROM is good.

   CD-ROM--good. CD-Audio--weeeelll...could be trouble. Keep in mind Red
Book audio does not require 100% error correction, so it would be pretty
likely the keys would not match given the tiniest data hiccup. A data mode
should work (i'd think).

<edit>Then you can send up to 600M of totally secure data before you
>dispose of the disks (Microwave oven is fun :) and write a new pair.

   3-4 sec. on High; no more, no less. Remove the oven bulb beforehand for
best viewing:)

))Sonic((
over 1192 CD players served, but who's counting?

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