Errata Page for

"John F. Byrne's Chaocipher: An Historical and Technical Appraisal"

Moshe Rubin (

This page lists the known errata found in the article "John F. Byrne's Chaocipher:  An Historical and Technical Appraisal".  
For corrected and up-to-date references in the article, see the up-to-date reference page.

Page 349, Figure 13: the step-by-step diagram of right disk permuting as presented in the article is incorrect.  The correct diagram is presented here:

Correct diagram for figure 13 on page 349

On page 331, the article describes Byrne's meeting to demonstrate his machine to the Navy in Washington:

Byrne showed up in Washington on 3 May 1938 to give his demonstration which, according to Byrne, never took place.  The panel of three Commanders included Samuel M. Tucker as an expert in radio and electronics, and Joseph N. Wenger as cipher expert.  After a short meeting Tucker suggested he should take his device either to the War Department or the State Department.

This was written based on Byrne's own description in Silent Years (page 279):

My correspondence with the Navy Department continued for several months; and by appointment, I went to Washington for a preliminary conference on April 4, 1938, and a few weeks later, on May 3, I returned again to Washington to give a demonstration of my device and principle - a demonstration which was not even begun before it ended abruptly.

At the proposed demonstration there were three Commanders - one a senior officer to preside; and two younger Commanders, whose names were Wagner and Tucker, as assayers.  Wagner being a cipher "expert" while Tucker was an expert in radio and electronics.  I can only say about this "conference" that it ended before it began with Commander Tucker sagely suggesting to me that I should take my device and system either to the War Department or to the State Department.

Based on Byrne's comment that "Tucker was an expert in radio and electronics", the article identified him incorrectly as Samuel M. Tucker.  We know today that he was [Rear Admiral] Dundas Preble Tucker.  According to this page:

Dundas Preble Tucker graduated from the U.S. Naval Academy in 1925

from 1934 - 1939 was Fleet Communications Officer and also in charge of electronic research. During World War II he was program director of Electronics and Guided Missiles for the Navy's Bureau of Ordnance, where he developed the BAT Guided Missile System, the first guided missile adopted for service use. From 1950 - 1953 he was director of the Navy's Electronics Laboratory.

He was the last direct descendant of Admiral Edward Preble, an early 19th century naval hero.

We know precisely who Tucker was because he wrote a letter to David Kahn following the publication of Kahn's "The Codebreakers".  In the letter he accurately describes what transpired in that meeting.  As Tucker writes, "I have remembered Byrne because of his lifetime devotion to what he regarded as a major invention, his arrogant condescension towards we smug and unappreciative bureaucrats, and his utter dejection when I made him see its impracticability ...".

The meeting took place in the office of the third, unidentified person.  From Tucker's letter we know that the third person was Lt. Commander Jennings B. Dow, Head of Radio and Sound Division (for a picture and biography from May 1946, see this page).

Copyright (c) 2018 Moshe Rubin
Created: 23 November 2018
Last updated:29 March 2021

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