Messages in this thread | | | Date | Wed, 15 Oct 1997 18:08:01 +0100 (MET) | From | Ingo Molnar <> | Subject | Re: monitoring entropy |
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On Wed, 15 Oct 1997, Colin Plumb wrote:
> The important thing is that it's information only in a Shannon sense. > Once you pass 4096 bits of output, it's theoretically possible to > derive the hidden internal state. It's just not remotely practicable. > It's like deriving the key to a cipher from the cipher output. Even with > a huge amount of output, a good cipher prevents you deriving the key.
isnt it so that generating enough cyphertext gives away the key after some time? I'm no cryptography dude, but i did read about the 'black box' attack, when you have a DES (government) hardware box, and you can pass it any known text, this way recovery of the internal state is much easier than a full search.
in a sense, the /dev/urandom thing is basically a black-box interface to some secret key.
Think about it. We cannot generate infinit amount of random output, based on a finit amount of random input. Ie. the output wont be random. The more output you give, the more information you expose, isnt it so?
-- mingo
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