The Chaocipher Clearing House

Progress Report #28

12 January 2023

Moshe Rubin (

This Progress Report is a compilation of Chaocipher-related information since Progress Report #27 (August 2020).

Here's a brief listing of items:

Chaocipher and Cryptology

Literary History (John F. Byrne, James Joyce)

Chaocipher and Cryptology

My ICCH (International Conference of Cryptologic History) presentation: "The Hunt for Chaocipher"

On 8 August 2021 I gave a WebEx-based presentation entitled "The Hunt for Chaocipher" to the members of the International Conference of Cryptologic History (ICCH).  In the ICCH's own words:

The International Conference on Cryptologic History (ICCH) is a forum for the discussion of cryptologic history. Established in 2004 as 'Crypto Collectors', the group includes members located in many countries around the world.

Every few weeks another member presents a web-based lecture on a cryptologic topic.  I have found ICCH members to be knowledgeable, interesting, and friendly.

My presentation lasted 1 hour 38 minutes, including Q&A following the presentation.

Several Chaocipher-related posts by Mark VandeWettering on his blog

Mark VanderWettering is the maintainer of a nifty blog called "brainwagon".  Mark jumped on the Chaocipher wagon (pun kind of intended :-)) a few days after I uploaded the first document that revealed how Chaocipher worked.  Over the next week, Mark authored several post related to Chaocipher:
They make interesting reading.  You can access them with the following query link.

Smith & Lewis submit  new cipher scheme

Between January and April of 1954, John F. Byrne attempted to commercialize Chaocipher, and turned to two engineers, Howard N. Smith and Howard W. Lewis, who were employed at Standard Oil, as potential marketers.  You can read John Byrne's (the son) letter to his father about having met the two engineers, and subsequent correspondences between John F. Byrne and Smith & Lewis can be found on the historical correspondence webpage.  It seems that nothing came out of that interaction.

It is therefore of interest to find, on the NSA website, that in November 1954, Smith and Lewis submitted a cipher system of their own to the NSA.  The document (cached here), written on 14 November 1954, uses terms highly reminiscent of Chaocipher as the basis of their cipher invention (pages 1-2).:

In order to describe the cipher, it will first be necessary to describe a simple device which can be used to illustrate the procedures for enciphering and deciphering messages. This device consists of two gears which have twenty-six teeth each or one tooth for each letter of the alphabet. The teeth on each gear are marked from "A" to "Z" in a clockwise direction. One of these gears is called the "message wheel" and the other is called the "cipher wheel" The wheels are free to rotate when engaged, and the cipher wheel can be disengaged from the message wheel, rotated or "indexed" from one to twenty-six teeth in a clockwise direction, and then re-engaged with the message wheel. Thus there are twenty-six possible engagements or the wheels. There are two fixed reference points, one for each wheel, which indicate the message-cipher relationship between the letters on the two wheels. This relationship is fixed for each engagement, and is different for each of the twenty-six possible engagements.

The document is somewhat long-winded, possibly expected for one written by people unschooled in the art of cryptanalysis.

On 21 March 1955, Major General Frank E. Stoner personally submitted Smith and Lewis's cipher proposal to William F. Friedman.  In the related correspondences found on the NSA website (cached here), we read how, on 1 April 1955, Friedman passed the task of investigating their cipher proposal to Col. F. E. Horrelko (USAF).  Col. Horrelko responded on 18 April 1955 that:

The system described in the brochure inclosed with the reference has been examined and found to incorporate no principles which are superior to those presently in use. It is a type of autokey (Vigenere) substitution wherein each key value is determined by the random selection of a letter, conversion of that letter to a displacement interval by a mixed canponent, and the corresponding displacement of the plain and cipher components from their preceeding aligrnnent. Alternate letters of the cipher are the encipherment of the randomly-selected (indicator) letters.

It is not known whether Byrne knew of this proposal made by Smith and Lewis, and one can only imagine what his reaction might have been had he found out.

CrypTool2 supports a Chaocipher visualizer

The CrypTool 2 open-source project is a boon for students of cryptography.  Here's how it describes itself:

CrypTool 2 (CT2) is a modern e-learning program for Windows, which visualizes cryptography and cryptanalysis. It includes not only the encryption and cryptanalysis of ciphers, but also their basics and the whole spectrum of modern cryptography.

CT contains over 200 ready-to-use templates with workflows. You can also easily combine and execute cryptographic functions to create workflows in CT2 by yourself (visual programming). With this approach, complex processes can be easily visualized and thus better understood.

CrypTool 2 provides many built-in functions that implement a plethora of cryptographic processes, and that includes functionality for implementing a Chaocipher system.

Once you've installed CrypTool 2, you can fire up a session, then search for "chaocipher" in the templates search control:

CrypTool 2 opening screen

Double-clicking the "chaocipher" template option opens a pre-written, ready-to-run Chaocipher implementation:

CrypTool 2 Chaocipher template

Take it out for a spin - the results will get you thinking of other uses for CrypTool 2.

Here are some other resources that will help:
If you're a developer or an educator, you will find this product of interest.

Near impossibility of solving Chaocipher without system knowledge

In 2020, the NSA declassified the third book of its awesome trilogy "Military Cryptanalytics".  This series, written byWilliam F. Friedman and his esteemed NSA cryptologist and protege Lambros D. Callimahos, finally revealed most of the cryptanalytic theory and techniques for tackling classic ciphers (tantalizing portions are still redacted for security reasons).

This event elicited an article by Richard Bean, entitled "Declassified Cold War code-breaking manual has lessons for solving ‘impossible’ puzzles" and published on The Conversation website.

Our interest in this article, besides its inttiguing premise, is its highlighting Chaocipher as a

This means you may have to eventually reveal the method you used. One example is a complex algorithm known as Chaocipher. While Chaocipher messages were designed to be highly difficult, they’re virtually impossible to decipher without knowing the method.

Looks like Chaocipher has made it to the big times <g>.

Chaocipher mentioned in "Uncracked Codes and Ciphers" (Ann Byers, 2017)

In "Uncracked Codes and Ciphers" by Ann Byers (2017), we find an intelligent summary of the history of Chaocipher indecipherability.  Byers notes that Byrne's Chaocipger papers were donated to the National Cryptologic Museum in 2012, and that the cipher secret was revealed.  However, she continues, it is not clear whether "the messages would be "absolutely indecipherable" by anyone except the intended recipients?  Cryptographers are still working to see if that is true."

YouTube video "Most DIFFICULT Codes That Were Ever CRACKED!" presents balanced description of Chaocipher

You can watch an intelligent description of Chaocipher in a YouTube video entitled "Most DIFFICULT Codes That Were Ever CRACKED!".  The relevant portion begins at time 8:38 and leasts for 1:11 minutes.

A 2019 Reddit thread entitled "Improving Chaocipher"

A 2019 Reddit thread entitled "Improving Chaocipher" raises interesting points. some that have been known to Chaocipher circles.  Much of the thread is based on PR Ruiz's blog "The Scrabble Cipher".

yamhill_pub wishes to improve Chaocipher by making the scrambling of the left and right wheels/alphabets after each encipherment part of the key.  Byrne's original scheme permutes the alphabets using the following Python-like slicing:

CT scramble: [0:1] [2:14] [1:2] [14:26]
PT scramble: [1:3] [4:15] [3:4] [15:26] [0:1]

Proposes to make the permuting slices part of the key.  So, for example, the permutation might be:

CT scramble: [0:1] [2:11] [1:2] [19:26] [14:19]
PT scramble: [1:3] [4:13] [3:4] [15:26] [0:1] [13:15]

Another topic mentioned is that Chaocipher is susceptible to enciphering a plaintext consisting of only one letter (e.g., all 'A's).

Mention is made to:
It turns out the Byrne used a related method to generate mixed left and right alphabets:

Scrambling left/right alphabet using a keying method

In this example, Byrne chose the keying phrase "CHAOCIPHER".  Beginning with straight A-Z alphabet for both the left and right alphabets, and given a key as to which alphabet would be the plaintext alphabet ("RRLLRRLRLR - right/right/left/left/... etc."), the alphabets are primed by enciphering the keying phrase.  Once enciphered, the remaining alphabets are the starting ones.  This is echoed by the Reddit poster "LolThisGuyAgain".

In the Reddit thread, as well in PR Puiz's blog, they recommend enciphering 20 random characters on left/right straight alphabets, then sharing these 20 random "plaintext" letters with the receiver via a different channel.

The CipherBrain blog presents a Chaocipher-like challenge: Christoph’s Chaotic Caesar Challenge

Claus Schmeh's CipherBrain blog is a fascinating website that features a continuous stream of real-life classical cryptographic puzzles and challenges (some pages are in German, just translate with Google Translate).

In May 2020 a column entitled "Christoph’s Chaotic Caesar Challenge" was presented, in which contributor Christoph Tenzer challenge readers to solve a cipher message using a cipher system of his creation.  Actually, Christoph's cipher system is a stripped-down version of Chaocipher.  Here is how Schmeh describe's Christoph's system:

In the following, we work with the standard English 26-letter alphabet. We need a keyword and a number n. As an example, we take the keyword CHALLENGE and n=3. The keyword is used to rearrange the alphabet in the usual way: Write the keyword first, omit repeating letters, append the remaining letters. For CHALLENGE, we receive:


To encrypt a plaintext, one starts with the first letter and performs the following steps (in the first step, the number n comes into play):
Using the keyword CHALLENGE and n=3, the plaintext TO BE OR NOT TO BE is encrypted as follows:

T returns W and then the positions of T and W are switched, so the alphabet is now: CHALENGBDFIJKMOPQRSWUVTXYZ

O returns R and then the positions of O and R are switched, and the alphabet is now: CHALENGBDFIJKMRPQOSWUVTXYZ

B returns I and then the positions of B and I are switched, and the alphabet is now: CHALENGIDFBJKMRPQOSWUVTXYZ

E returns I and so on ...

Here’s the ciphertext: WRIIUUDXZACMM

The cipher uses Chaocipher's concept of dynamic substitution, this time on a single alphabet.

What TCCH readers will find of interest is the number of high-profile cryptanalysts (e.g., George Lasry, David Oranchak) that weighed in on this challenge, and the discussion that follows on how they solved this and another challenge message.

Literary History (John F. Byrne, James Joyce)

Glenn Johnston's photos of John F. Byrne's places of residence

In August 2020 I received an email from Glenn Johnston, in which he wrote:

I am very interested in John F. Byrne as a result of a passion for James Joyce, and have found it to be a great resource. I have visited Byrne's New York addresses as identified in the Chaocipher letters and have attached pictures of 2069 Nostrand Avenue, 1114 New York Avenue, and 1647 Macombs Rd. (The Wilson St. and Long Island City buildings have been replaced.)

Glenn kindly provide TCCH with high-resolution photographs of three of the buildings that John F. Byrne had resided in.  You can see the images here:

Two photos of John F. Byrne, available on the UCD (University College Dublin) Digital Library website

The Cryptologia paper "John F. Byrne's Chaocipher Revealed: An Historical and Technical Appraisal" (October 2011) presented two photographs of John F. Byrne on page 340:

John F. Byrne circa 1924 John F. Byrne  at La Bergerie

These photos, originally from the Constantine Peter Curran photographic collection, now resides in the UCD (University College Dublin) Digital Library.  Click on either photograph to link to the respective UCD webpage.

The introductory letter sent to Patricia Byrne after locating her

As told over elsewhere on this website, Patricia Byrne, John Byrne's wife and John F. Byrne's daughter-in-law, was located by cold-calling telephone numbers belonging to people named Byrne in the state of Vermont in the United States.  On 9 August 2009 I fortuitously called Patricia Byrne.  Pat Byrne was then almost 90 years old, in frail health, and she wanted to know who I was and what my interest in Chaocipher was.  In the conversation she gave me her post office box address, which enabled me to send her a well-thought out postal letter addressing her suspicions.

I spent the next few weeks investigating the best course of action for her, with a view to enabling her to patent Chaocipher before opening it up to the computer world for evaluation.  Once I had investigated the options, I wrote her a personal letter presenting the options.

You can read this initial letter to Pat Byrne here.

Byrne and Chaocipher mentioned in Leah Culligan Flack's "James Joyce and Classical Modernism"

Leah Culligan Flack's book "James Joyce and Classical Modernism (Classical Receptions in Twentieth-Century Writing)" contains several Chaocipher-related passages.  Here they are for the record:

Leah Flack - Chaocipher on page 23

Leah Flack - Chaocipher on page 24

Leah Flack - Chaocipher on page 39

"The So Called Real Person Who Lived at No.7 Eccles St." (by Elaine Byrne)

Elaine Byrne, a resident of Wicklow County in Ireland, has authored an extended and informative article on the close relationship between James Joyce and Wicklow man, John Francis Byrne, who was a distant relative of Elaine  The article, entitled "The So Called Real Person Who Lived at No.7 Eccles St", fleshes out so many passages found in Byrne's autobiographical "Silent Years", adding invaluable information for those who are fascinated by the biographies of Byrne and Joyce.  The paper adds so much new information pertaining to Byrne's roots in Wicklow.

The paper can be found in Wicklow Roots, The Wicklow County Genealogical Society Journal, No. 9 (2004), published by Wicklow County Genealogical Society, Wicklow Town, Co. Wicklow, Ireland.  The introduction and the genealogical notes on the Byrne Family were added by the editor of the journal, the late Declan Byrne.

John F. Byrne's entry in the Dictionary of Irish Biography

The online Dictionary of Irish Biography carries a page dedicated to John Francis Byrne.

John F. Byrne's official date of death

Until Elaine Byrne shared her "The So Called Person Who Lived at No.7 Eccles St." (see the previous item on this page), I knew that John F. Byrne was born on 11 February 1880, but was only aware that his date of death was in the year 1960.  Nowhere has I come across an obituary or other source that told us his full date of death.

Even the scholarly Dictionary of Irish Biography lists his full date of birth, but mentions only his year of death.

On page 19 of Elaine Byrne's excellent work we find the following letter sent by Byrne's first wife, Alice (Headen) Byrne to Constantine Peter Curran (1883-1972), a lawyer and historian of 18th Century Dublin architecture, sculpture and plasterwork.

John F. Byrne's date of death

Now we know Byrne's full date of death: 29 April 1960.

Two book reviews of John F. Byrne's "Silent Years":

"The Cryptogram In Joyce’s Ulysses: A Misprint" (Publications of the Modern Language Association of America (PMLA) , September 1958)

In Ulysses, Leopold Bloom’s locked private drawer at 7 Eccles Street contains, among other things:

3 typewritten letters, addressee, Henry Flower, c/o P.O. Westland Row, addresser, Martha Clifford, c/o P.O. Dolphin’s Barn: the transliterated name and address of the addresser of the 3 letters in reversed alphabetic boustrophedontic punctated quadrilinear cryptogram (vowels suppressed) N. IGS./WI. UU. OX/W. OKS. MH/Y. IM …

As David Kahn writes (The Codebreakers, page 767, in the footnote):

It may not be coincidence that in Ulysses an inventory of Mr. Leopold Bloom's locked private drawer at 7 Eccles Street included among other things "3 typewritten letters, addressee, Henry Flower, c/o P.O. Westland Row, addresser, Martha Clifford, c/o P.O. Dolphin’s Barn: the transliterated name and address of the addresser of the 3 letters in reversed alphabetic boustrophedontic punctated quadrilinear cryptogram (vowels suppressed) N. IGS./WI. UU. OX/W. OKS. MH/Y. IM …"  "Quadrilinear" meant to set the cipher in four lines; "reversed alphabetic" indicated the key of a = Z, b = Y, etc.; "boustrophodontic," and adjective concocted from the adjective "boustrephodon,", a technical term in paleography referring to writing that runs left and right in alternate lines, indicating that the lines of the cryptogram were to be read in that way.  Unfortunately, Joyce or Bloom forgot about this in the fourth line, which incorrectly reads left to right.  The cryptogram and its solution thus are:

N . I G S .
m a r t h a

W I . U U . O X
d r o f f i l c

W . O K S . M H
d o l p h i n s

Y . I M
b a r n

In the Publications of the Modern Language Association of America (PMLA), 1958-09: Vol 73 Issue 4 (pages 446-447), you can find an interesting article entitled "The Cryptogram in Joyce's "Ulysses": a Misprint", written by Grover Smith, Jr. of Duhe University, which discusses errors in later editions of Ulysses.

Smith notes the following:

As one might suspect upon examining the description and as one learns upon comparing early editions of Ulysses, Joyce did not write "reserved alphabetic," which means nothing; he wrote "reversed alphabetic." Unlike neighboring corruptions in the text, the misprint reserved has obscured the sense and has prompted erroneous interpretation. For example, Stuart Gilbert, supposing that reserved concealed 'a secret name,' has imagined that "the clue to this reservation may be found in the Black Mass of Circe."  Anyone in possession of Joyce’s original phrase can decipher Bloom’s memorandum without any such cross reference, the purport of which remains mysterious.

I bring this item because of footnote number 3 in Smith's article on page 446, which reads:

[3] Ibid. J. F. Byrne, in Silent Years: An Autobiography with Memoirs of James Joyce and Our Ireland (New York: Farrar, Straus and Young, 1953), pp. 161-162. calls Gilbert’s comment “‘odd” and concludes that he is “floundering.” Byrne seems thus unaware of the misprint. Byrne, the model for Cranly in Joyce’s Portrait of the Artist as a Young Man, lived at No. 7 Eccles Street from 1908 to 1910. In 1918 he himself invented a ciphering system called “Chaocipher” (Silent Years, pp. 264-307).

Here's what Byrne wrote in "Silent Years" (pages 161-162):

In that paragraph wherein are detailed the contents of "the first drawer unlocked" there is this item: "the transliterated name and address of the addresser of the 3 letters in reversed alphabetic boustrephodontic punctuated quadrilinear cryptogram (vowels suppressed)    N.IGS./WI.UU.OX/W.OKS.MH/Y.IM"  That the long word "boustrephodontic" is misspealled is of no consequence: but Mr. Gilbert's reference to this cryptogram is odd.  He says of it in a footnote: "The second word, a secret name, is 'reserved'; the clue to this reservation may be found in the Black Mass of Circe.  Here one could charitably suppose that Mr. Gilbert's use of the word "reserved" was a slip of the pen, but when he goes on to amplify his remark by reference to "this reservation"; and when he says vaguely where the "clue may be found" he is clearly floundering."

It is obvious that Byrne was quoting the correct original edition of Ulysses, where the phrase used was "reversed alphabetic", and not "reserved alphabetic".  Smith's point is that Byrne was not aware of corruptions in later editions, and therefore was impatient with Gilbert's "odd" and "floundering" interpretations.

The lesson here is that researchers should always check the first edition of a book they are critipuing to guarantee they are not building on a corruption.

The Harvey Breit Correspondence collection features two letters from 1952

Harvey Breit was an American poet, editor, and playwright as well as reviewer for The New York Times Book Review from 1943 to 1957.  His connection to John F. Byrne is two-fold: "Silent Years" is dedicated to Harvey Breit, and Breit wrote the foreword in "Silent Years.

The Briet's correspondences are located in the Harvey Breit Correspondence, 1940-1965, Manuscript Series I, Charles Deering McCormick Library of Special Collections, Northwestern University Library.  The collection contains two letters sent between them.

John Byrne (the son) sighted at the James Joyce Tower and Museum in 1965

In the article "Early Joyceans in Dublin", written by Vivien Veale Igoe and published in the periodical Joyce Studies Annual, Volume 12, Summer, we find an interesting Byrne-related anecdote.  On page 84 we read about Harry Pollock, the founder of the James Joyce Society in Canada, meeting John Byrne, the son of John F. Byrne:

Harry Pollock meets John Byrne in 1965

The meeting took place in the James Joyce Tower and Museum in Sandycove, Dublin.

John Byrne (the son) Social Security information

John Byrne (the son) Social Security information

National Library of Ireland (NLI) has ten (1) letters related to John Francis Byrne

The National Library of Ireland (NLI) has ten (10) letters related to John Francis Byrne in their possession.  Most of the letters are his correspondences with Francis Sheehy Skeffington, but the last item may hold interesting biographical information about Byrne:

Main Creator Lyng, John J.
Contributors O'Brien, William, 1881-1968
Summary Lyng quotes a passage from Byrne's book, describes some of his life and notes that he wrote under the pseudonym "Renby - an anagram of Byrne".
In collection William O'Brien (1881-1968) Papers, 1898-1969
Format Manuscript
Language English
Subjects Lyng, John J. > Correspondence
O'Brien, William, > 1881-1968 > Correspondence
Connolly, James, > 1868-1916
Byrne, John Francis, > 1880-1960
United States > History > 20th century
Notes Includes annotations by O'Brien of page numbers and the date he replied "2/12/61".
Physical description 1 item (1 page)
Arrangement Item

Here are the bits from the last item relevant to Byrne:

Dear Bill, - The following quotation from “Silent Years” may be new to you.

Page 112 “The head & front of the immediate active group was James Connolly … He was about 40 yrs old, stocky build, earnest, bullet headed, & determined to the degree of obstinacy. He spoke with a pronounced accent which might be North of Ireland, but seemed to me like Scotch.” Page 112 – “Silent Years” by John Francis Byrne, First printing, 1955 in New York by Farras, Straus & Young.

J. F. Byrne worked as a financial writer for the Fairchild Publications under the pen name of J. F. Renby. He stayed5 or 6 years & was eased out during the depression about 1933 after F.D.R. became Pres., U.S.A. I spent 30 yrs. With the same firm. I only knew that Renby was a Dublin man, but never tried to contact him as the firm was averse to “Union men” trying to spread their ideas with the unorganized “Brain Trust”. However, they were later organized by the Newswriter’s Guild, sponsored by Heywood Broun, a columnist of the now defunct, N.Y. World.


J. F. Byrne lived at 7 Eccles St. in the vicinity of 43 Belvidere Place & you probably met him with Joyce, while he stayed there.

Hoping you and Cissy are well and able to keep moving as all here are fairly comfortable.


John J. Lyng

P.S. RENBY – is an “Anagram of Byrne”

Bruce Pandolfini, the chess master and teacher, mentions John F. Byrne

Bruce Pandolfini is an American chess author, teacher, and coach, and is generally considered to be America's most experienced chess teachers.

In 1988, Pandolfini was featured in Fred Waitzkin's book "Searching for Bobby Fischer" (1988), a perceptive narrative on his talented son Josh and Josh's successes in the world of children's chess. The book later (in 1992) became a Paramount Pictures film of the same title, in which Pandolfini, Josh’s real-life teacher, was portrayed by award-winning actor Ben Kingsley.

Pandolfini was a consultant to The Queen's Gambit, a 2020 American Netflix miniseries, where he also had a cameo role as a tournament director. He had also been a consultant to the original 1983 novel, for which he suggested the title.

His connection to Chaocipher can be seen in one of his his 2001 web-based columns entitled "The Q&A Way":

Question In reading one of your past answers it seemed that you might know something about James Joyce and Samuel Beckett as chess players. Somewhere I heard that Joyce and Beckett both played chess. Do you know anything about this? Warren Anderson (USA)

Answer From the little I know Joyce didn’t play chess at all, and though he made several inscrutable references to chess in Finnegan’s Wake, it appears that he actually detested the game and its passionate adherents. I recall some story about his association with J. F. Byrne, an avid chessplayer and owner of 7 Eccles Street, the house where Leopold Bloom “ate with relish the inner organs of beasts and fowls.” Apparently Joyce would meet Byrne at a local pub, which happened to contain a few chess tables. Since Byrne was invariably playing chess, Joyce would have to sit idly by until the session’s completion, no matter how long it took, and there’s no evidence that Joyce ever had an epiphany to participate.

Copyright (c) 2023 Moshe Rubin
Created: 12 January 2023
Last Updated: 15 January 2023

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