The Chaocipher Clearing House

Progress Report #13

Moshe Rubin (

Mike Cowan submits research paper entitled "A new approach to revealing the Byrne machine"

This afternoon I received a technical submission from Mike Cowan entitled "A new approach to revealing the Byrne machine".  It is a new approach to attacking the Chaocipher, using the plethora of known plain and cipher text letters found in Exhibit #1.  Assuming the underlying system uses two cipher disks, Mike proposes determining the mixed disk alphabets in a novel fashion.

Mike's approach, both drawing on Jeff Hill's work and parallel to it, holds the promise of breaking into Chaocipher in a novel way.  Highly recommended reading.

A C++ file of Mike's prototype program that illustrates the principles of the method can be downloaded from here.

Copyright (c) 2009 Moshe Rubin
Created: 29 July 2009
Updated: 2 September 2009

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