Re: CPRM

From: Harvey Newstrom (mail@HarveyNewstrom.com)
Date: Wed Jan 24 2001 - 09:22:45 MST


>Adrian Tymes wrote:
>
>> Eh, even if it does happen: it's either a tax on those who can't look
>> up how to break the copy protection (there's always a way, in the weak
> > schemes that have been deployed on large scales so far), or the demise

Actually there are PGP-like schemes already in use for satellite TV
that are pretty much unbreakable. They use private/public keys to
encrypt the signal so that it can only be decrypted with the proper
key. Then they encrypt the proper decryption key in a short private
message to every box that is subscribed. Each box must decrypt its
own private message to get the decryption key for the signal. Boxes
that are not on the subscription list never get the key sent to them.

Breaking that encryption would require breaking asymmetrical
encryption on very short messages of just the key length. There also
is no good check to tell when you've broken the key. Computers are
not very good at detecting the difference between a clear frame of
video or a frame of random pixels. This slows down the process even
more.

-- 
Harvey Newstrom <HarveyNewstrom.com>



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