The Chaocipher Clearing House

What's New?

Moshe Rubin (

I began this website update history in October 2009.  The purpose is to enable returning visitors to easily track new changes and discover the latest additions.  Be sure to use your browser's 'Refresh' button to view the latest version of this page.

Date Page Link Update Description
16 November 2019 Returned to updating this page after a hiatus.  Several uploads:
  • Diagram of Chaocipher wheels inserted at top of home page
  • Color scan of chapter 21 ("Chaocipher") from John F. Byrne's "Silent Years"
  • Byrne's worksheet dated Monday, 5 July 1937 enciphering the first line of Exhibit #1
18 January 2013 Progress Report #21 x Updated the page to note that the Chaocipher article in Cryptologia can now be downloaded for free.
27 April 2012 Progress Report #21 x Chaocipher paper published in Cryptologia, Patricia Byrne passes away at 92
7 April 2011 Information about Henry E. Langen x Henry E. Langen's complete notes and summary of all his dealings with John F. Byrne and Chaocipher.
1 April 2011 Historical Correspondences x Added original Hitt-Byrne letter corresponding to the quotes brought in Silent Years, page 273.
18 December 2010 Progress Report #20 x Mike Cowan submits a new paper: "Chaocipher: Solving Exhibits 1 and 4"
19 November 2010 Progress Report #19 x Uploaded Jeff Calof's paper ""Silent Years" - Chapter 21 (Chaocipher) Examined: Analyzing Byrne’s Assertions".
8 August 2010 Progress Report #18 x Uploaded a paper providing an in-depth analysis of Exhibit 1 found in Byrne's "Silent Years".
2 July 2010 Progress Report #17 x Chaocipher revealed: the actual algorithm is described publicly for the first time.
1 June 2010 Progress Report #16 x The National Cryptologic Museum Foundation (NCMF) acquires the Chaocipher machine and papers
29 March 2010 Progress Report #15 x Initial uploading.
18 December 2009 Progress Report #11 x Mike Cowan correctly pointed out an error in the analysis that ruled out a C98 MM2 model with steps of 1/1/2/4.  The error and correction are now noted on the page.  The result that this model is ruled out remains unchanged even after the corrections.
20 November 2009 Information about Henry E. Langen x Two articles from the American Cryptogram Association's periodical "The Cryptogram": a biography when he became editor in 1952, and an obituary in 1962.
19 November 2009 List of pt/ct indentities in Exhibit 1 x Four intervals were not sorted by offset.
31 October 2009 Progress Report #14 x Added Mike Cowan's opinion regarding the significance or insignificance of no intervals less than 9.
30 October 2009 Progress Report #14 x
24 October 2009 Historical Correspondences x Added link to 6 February 1957 letter from WFF to JFB
23 October 2009 TCCH homepage x Added link to J. F. Byrne chronology

Copyright (c) 2009-2019 Moshe Rubin
Created: 23 October 2009
Updated: 16 November 2019

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