30 September 1998

Date: Wed, 30 Sep 1998 14:02:49 -0500
To: cypherpunks@toad.com
From: Bruce Schneier <schneier@counterpane.com>
Subject: Announcement: A Self-Study Course in Block Cipher Cryptanalysis

Ever since writing Applied Cryptography, I have been asked to recommend a
book on cryptanalysis.  My unfortunate answer is that while there are
several good books on cryptography, there are no books, good or bad, on

The only way to learn cryptanalysis is through practice.  A student simply
has to break algorithm after algorithm, inventing new techniques and
modifying existing ones.  Reading others' cryptanalysis results helps, but
there is no substitute for experience.

To help in getting this experience, I designed a self-study course in
block-cipher cryptanalysis.  With it, a student can follow an ordered path
through the academic literature and emerge out the other side fully capable
of breaking new algorithms and publishing new cryptanalytic results.

What I have done is to list published algorithms and published
cryptanalyses in a coherent order: by type of cryptanalysis and difficulty.
A student's task is to read papers describing algorithms, and then attempt
to reproduce published cryptanalytic results.  (It is definitely more
difficult to learn cryptanalysis from academic papers than from a distilled
textbook, but the sooner a student gets used to reading academic papers the
better off he will be.)  The results, in other published papers, serve as
an "answer key."

The paper is available in both postscript and pdf formats at:


Comments are always appreciated.

Bruce Schneier, President, Counterpane Systems     Phone: 612-823-1098
101 E Minnehaha Parkway, Minneapolis, MN  55419      Fax: 612-823-1590
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