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Re: Applied Cryptography Questions

Anonymous (hence the public reply) writes:
> A couple questions about Applied Cryptography (Second Edition)

I only have the 1st, but I won't consult it for this anyway....

> 1. What on earth is a Neural Net?

This sounds like a troll, since we recently had a thread about the possible
use of neural nets in cryptographic applications, and the precise text used
in AC2 to discuss this matter. Very roughly, a neural net is an abstract 
model of a network of neurons in a brain, used in artificial intelligence as
a model of computation. I imagine you could easily have found more complete
information by doing some trivial net search for "neural net".

> 2. Consider the Chinese Lottery attack vs a processor bank.
>      Distributed computing, no easy bombing target.
>      39% inefficient
>      Need specialized hardware [for speed] or transmission of alogrithms
>        for any specific alogrithm
>      Not on all the time
>      If value(crack) * cracks/chip > cost of chip, then why not have
>        the gov buy the chips? Its probably cheaper that way.

Well, is it in fact "probably cheaper" ?  If value(crack) > cost(chip) >
cost(attack) then the attack makes more sense....

> 4. Does there exist an n such that a keyspace of 2^n is trivial to crack
>    [ie a matter of miniutes] on a PC but is difficult to crack for a 
>    big commercial company or even a major government? [this question
>    relates to Merkle's puzzles, when a 40-bit key seems a bit weak.]

I think you need to explain more for this question to make sense. Obviously
companies (even big ones) and governments (even major ones) could buy and use
PCs themselves, in the event that conferred some cryptanalytic advantage.

ObLycos: Hey, better still, let's put the archives in an export-controlled
directory. We don't want too many outsiders to hear about the privacy
advantages of strong cryptography, now do we ?

ObAlices: <yawn>

-Futplex <[email protected]>
"I look pretty young but I'm just backdated" -The Who