From: tcmay@got.net (Timothy C. May)
Date: Sun, 10 Mar 1996 11:04:24 +0800
To: cypherpunks@toad.com
Subject: Re: Cryptanalysis
Message-ID: <ad676d9b0c021004b946@[205.199.118.202]>
MIME-Version: 1.0
Content-Type: text/plain


At 11:57 PM 3/9/96, E. ALLEN SMITH wrote:
>From:   IN%"tcmay@got.net"  9-MAR-1996 12:05:04.70
>
>>There are very good reasons to say little about "conventional
>>cryptanalysis": it just doesn't matter much with modern ciphers, such as
>>public key systems. Modern ciphers don't fall to conventional attacks based
>>on word frequency, pattern analysis, etc.
>
>        I realize that this may also be considered an out of date subject,
>but what's a good reference for codes as opposed to cyphers (other than
>the one reference in the Cyphernomicon which includes "codes" in its title)?

The usual: Kahn, Denning, and some of the old Dover Press books on crypto.
Also, Herbert Zim wrote a nice little book about 40-50 years ago on codes.
Some of the standard crypto textbooks will of course have more pointers to
cryptanalysis. (Not to sound harsh to Allen, but why would anyone ask here
on the list for recommendations to such a standard subject when Schneier,
Garfinkel, Denning, etc. all have books listed?)

Again, the reason stuff like "word frequency counts" and "index of
coincidence" notions are so seldom involved in modern crypto--which is what
all public key systems involve--is that they are essentially of no use.
There is no point in doing statistical analysis of patterns on the
ciphertext in an RSA or similar encryption. (Because any "patterns"
discovered are meaningless.)

And there are so many interesting areas to pursue with using and furthering
modern crypto, that I just can't understand how people can think that
classical cryptanalysis is useful. It might be fun, as a hobby, but it has
no bearing on modern systems. (Well, I'm exaggerating a bit. I suspect that
classical cryptanalysts at the NSA or GCHQ might have some insights into
some problems with modern systems, such as traffic analysis. So I shouldn't
say there is "no use" for it. But I hope you all understand my point in
general. It is unlikely in the extreme that anyone who fools around a
little with classical cryptanalysis will have anything important to
contribute as a result of this.)

--Tim May

Boycott "Big Brother Inside" software!
We got computers, we're tapping phone lines, we know that that ain't allowed.
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Timothy C. May              | Crypto Anarchy: encryption, digital money,
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