Applied Cryptography Questions

[nobody@REPLAY.COM (Anonymous)]

A couple questions about Applied Cryptography (Second Edition)

1. What on earth is a Neural Net?

2. Consider the Chinese Lottery attack vs a processor bank.

   ADVANTAGES
     Distributed computing, no easy bombing target.

   DISADVANTAGES
     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.

3. How does one cryptoanalyize a Feistel Network? I've read a bit
   on this and it doesn't seem that the papers are consistant,
   for example, one claims that 2^32 chosen plaintext is unreasonable
   for a 64-bit block cipher whereas DES's cryptanalysis requires
   something like 2^42.

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.]

5. Is there an errata yet?