London Prostitutes at the Trojan War: Betrayals of ESF [part 2 of 3]
Another episode in the cryptographic Bacon-Shakespeare saga, where the main character this time is Elizebeth Smith Friedman. An exceptional woman who managed to deceive almost everyone. That is, except for the NSA...
The first truly substantial book about the life and work of Elizebeth S. Friedman (1892-1980) — the most famous female cryptanalyst in the United States and a devoted wife to the even more renowned cryptologist William F. Friedman — was published by journalist Jason Fagone in 2017 under somewhat tantalizing title: The Woman Who Smashed Codes: a true story of love, spies, and the unlikely heroine who outwitted America’s enemies [o1].
Such biographical works are typically referred to as panegyrics. That is, enthusiastic, generously embellished, and utterly uncritical praise of heroes. Or, in this case, a cryptographic heroine — an exceptionally intelligent, perceptive, and talented woman. The book’s title is given additional piquancy by the fact that Elizebeth S. Friedman managed to successfully deceive not only the "America’s enemies" but also her fellow Americans and nearly everyone else — anyone who has heard of this “unlikely woman”...
To fairly assess both the degree of truth and the significant portion of brazen falsehood or more subtle half-truths extracted by Jason Fagone from memoirs and interviews with ESF, it's necessary to compare his book with another biographical work. Published exactly 40 years earlier, in 1977, and with a not coincidentally similar title: The Man Who Broke Purple: The Life of the World’s Greatest Cryptologist, Colonel William F. Friedman. [o2]
The earlier work — still the only biography of William F. Friedman to date — was written by British journalist and writer Ronald Clark (1916-1987) under significant influence from personal interactions with his widow, Elizebeth S. Friedman. This is precisely why even in the title of his book, the author managed to make at least two serious factual errors and one rather controversial assessment.
For the indisputable facts of history are such that William F. Friedman, firstly, wasn't the person who broke the Japanese Purple cipher. Secondly, he never held the military rank of colonel. And thirdly, the title "world's greatest cryptologist" certainly sounds impressive (especially to the devoted wife, journalists, and their readers), but in relation to WFF's work and achievements, such an assessment can only be interpreted as a somewhat ambiguous spy joke. Especially following the exposure of the greatest (without exaggeration) crypto-deception involving Hagelin Crypto AG cipher machines, in which William Friedman played the leading role. [i1][i2]
Jason Fagone, as a thorough biographer with access to a far greater body of declassified information than Ronald Clark had in the 1970s, doesn't make such serious errors. However, his book still presents the critical early period of the joint biography of the cryptographic couple W.F. and E.S. Friedmans, associated with the Riverbank Laboratories of George Fabyan and Baconian ciphers in Shakespearean texts, in full accordance with Elizebeth S. Friedman's accounts from the twilight of her long life.
This is hardly surprising. For the same has always been done and continues to be done by all other historians of cryptography. To be precise, almost all — except for one notable exception: the NSA’s Center for Cryptologic History. In 2023, they published a work with a new — substantially more truthful — account of the early American history of military-intelligence cryptography. [i1][o3].
Aligned with factual accuracy, the new version of this history delicately refrains from calling everything that was written and said by the Friedmans in their later years about their youth, their work at Riverbank, Fabyan, and Bacon-Shakespearean ciphers, as lies and disinformation. Instead, the new historical book from the NSA does something else. All stories about the deeds and achievements of the most famous pair of cryptologist heroes are now completely separated from the topic of Baconian ciphers in Shakespeare's books and other authors of the Elizabethan era...
Since for our investigation, this topic — the impressive successes of young Elizebeth Smith (not yet Friedman) in deciphering Baconian ciphers — is now central, this is where we'll detail what interesting events took place in 1916 at the Riverbank Laboratories of George Fabyan. And why ESF, in her old age, told so many untruths about it.
As previously noted, every lie, whether big or small, is always, to some extent, an act of betrayal and treachery. Unlike WFF, who desperately sought to "make a name" for himself by any means possible, ESF clearly didn't have the same drive for fame. However, she was an absolutely devoted wife, well aware of her husband's talents, understanding his ambitions, and sharing his constant feeling of being undervalued. Consequently, Elizebeth Smith Friedman was willing to do anything to glorify her husband's name and achievements, both during his life and after his death.
Unfortunately, the main tools in this "quest for glory" turned out to be lies and betrayal. A multi-layered lie about the events at Riverbank and betrayal by cryptographer scientists of the well known to them scientific truth.
The reasons for this unfortunate outcome are generally clear. Due to the deeply secretive, and thus completely obscure, nature of William Friedman's work in military intelligence, the only real opportunity for fame and recognition during his lifetime came from the Bacon-Shakespearean topic. For despite his efforts, the so-called "world's greatest cryptologist" Friedman was unable to decipher any other famous historical mysteries — such as the Voynich manuscript or Maya writing.
Since William Friedman couldn't have been the first, or even the second, to decipher Baconian ciphers in Shakespearean texts — where everything interesting had already been deciphered before his arrival — the path to fame for him opened up in a different way. Clearly dishonest, but quite suitable for the cynical profession of spies. In their work, as is well known, spies constantly rely on the principles of “Denial and Deception.”
As a person undeniably intelligent and perceptive, Friedman always saw that the scientific-historical and literary establishment was originally and categorically unwilling to acknowledge the cryptographic successes of the Riverbank Laboratories in decoding Baconian ciphers. For in the endless debates over Shakespearean authorship, official science always firmly adheres to a single line — maintaining the long-established status quo: Shakespeare was Shakespeare. [i3]
For WFF and his devoted wife, this steadfast scientific line once gave rise to an unconventional path to fame: to present the cryptographic achievements of Riverbank in a way that would please the establishment [i5]. After all, in official scientific circles, there could never have been, and couldn't be, Baconian ciphers in ancient books. The Friedmans took this idea as an offer they could not refuse...
Details about how WFF and ESF created their predictably successful monograph The Shakespearean Ciphers Examined [o4], which was immediately recognized with awards, prizes, and media attention upon its release, can be found in the investigative book 4in1 [i4]. Here, however, we'll focus on the details of how Elizebeth Smith Friedman consolidated the success after her husband’s death.
For William Friedman to appear as the “greatest and most brilliant cryptologist,” it was necessary to depict those around him as petty and insignificant. Therefore, in her interviews and memoirs, ESF regularly added more and more episodes and details designed to discredit both Colonel Fabyan personally and almost everything done in his Riverbank Laboratories before the U.S. entered the war in 1917.
One particularly vivid example of this is the acoustic levitation machine [i6], which in ESF’s recollections was transformed into a perpetual motion machine.
In a major interview from 1974 [o5], this episode of history was presented by ESF as follows:
... Then at twenty three his [Fabyan's] father died and left him three million dollars. I think it was three million. Anyway, it was somewhere in the millions and so with that he started to work up this idea of having all these research departments doing things of one kind or another.
And, of course, one of the things that he fell for which shows his lack of education was the biliteral cipher of Sir Francis Bacon which Mrs. Gallup claimed proved that Bacon wrote Shakespeare. And she had published in 1899, quite a while previous to all this, she’d published a book about this thick and this big.
And he got the idea of getting a number of young college graduates who were interested in the subject of Shakespeare to come out there and learn from Mrs. Gallup, what she had discovered, quote discovered, close quote, and so we began to work.
These crazy ideas even included the fact that Fabyan believed in perpetual motion and he was going to have this person, whomever it was he was going to get, he was going to have him work on theories. He had a thing that he called a perpetual motion machine which was out back of the laboratories. I remember going, looking at it for quite a while, and it just seemed to me like a great, huge metal something-or-other. But he didn’t. I guess he got so much ridicule from the perpetual motion idea that he gave that up shortly and didn’t adhere to it.
In another major interview from 1976 [o6], the same story was recounted as follows:
Valaki: To what extent did he [Fabyan] contribute, himself, in cryptology or, say, in acoustics?
Friedman: Well, now, I can't answer too much on acoustics except to show you that it is true. And he did. Vile creature that he was in many ways, George Fabyan really launched two or three things that were of vital importance to this country. And he stumbled upon these when he was wading his way through this myriad of cipher stuff that he got onto. Of course, the cipher stuff was not so...
Well, I mean, a rarified kind of thing. In other words, the acoustics studies that were made at Riverbank, well, he certainly deserves credit.
And the same way with this ordnance stuff that developed -- not with anything that we had do with at all, although we did have to do with everything except this at Riverbank -- was this ordnance engineer who ... He was kind of a country bumpkin.
You know, he'd never been anywhere or done anything. He just wanted to fiddle around with pieces of iron and this and that. But he developed a lot of stuff for the Army ordnance. And his name was Eisenhaur. E-I-S-E-N-H-A-U-R, I think, it was spelled.
... So there were lots of things ... Somehow we managed to get a lot of fun out of things out at the Riverbank. Because we who really understood the sciences that he [Fabyan] was promoting so vigorously were wondering where it was all going to lead to, convinced that he had something valuable and it should lead somewhere.
And then, others... It was just kind of fiddling... He fiddled around with everything. He had stuff out back of the acoustics chamber, on the ground back there... that had to do with (she pauses) ... Oh, what's that scientific principle that's ... ? Hmm! Well, ... perpetual motion!
Valaki: Oh!
Friedman: He was determined there was such a thing as perpetual motion, and he was going to prove it...
At this point, it is necessary to interrupt such intriguing memories of ESF to present a description of the same episode from Riverbank’s history — the appearance of a rather strange machine — but now from the perspective of other Laboratory staff [o7], current physicists specializing in acoustics:
In 1913, Colonel George Fabyan was in dire need of an acoustical consultant to assist with a scientific project being conducted on his estate. This particular Riverbank project dealt with the building and testing of an acoustical levitating device constructed from a seventeenth-century description of a similar machine written in code by Sir Francis Bacon and deciphered by Elizabeth Wells Gallup.
Mrs. Gallup had come to Riverbank just after the turn of the century to continue her life-long search for proof that it was actually Bacon who had written the Shakespearean plays. During her research, she discovered that Bacon was a member of the Rosicrucian Society of England, a clandestine organization whose activities included conducting scientific experiments. Because this type of activity was interpreted by some to be witchcraft, the Rosicrucians had to carry out the experiments and divulge their findings in secret.
According to Mrs. Gallup, Bacon applied the same coding technique in many of his personal writings. This is referenced in the galley proofs of “The Fundamental Principles of the Baconian Ciphers,” dated 1916, a document the colonel dedicated to his mother. In this work Mrs. Gallup included various poems, short stories, and nursery rhymes, along with explanations of a variety of the society’s experiments — one of which was an experiment with an acoustic levitation device.
Immediately after she deciphered the description of this so-called antigravity machine, Mrs. Gallup informed Colonel Fabyan. The colonel responded by hiring Bert Eisenhour, a civil engineer from a woodworking firm in Chicago, to construct the device.
A significantly more detailed account of this episode can be found in the memoir “Early History of Riverbank Acoustic Laboratories” [o8], published in the early 1970s by Fred W. Kranz, one of the first acoustics staff at Riverbank. In its substantive part, this text is almost entirely quoted in the chapter “Bacon, Rosicrucians and Levitation” [i6] of the book “4in1” [i4].
Comparing the memoirs of the celebrated cryptographer ESF and those of the acoustics scientists, dedicated to the same episode from Riverbank’s history, it's not difficult to see how significantly the facts differ from the fabrications. Among the crucial manipulations of truth are:
- the complete removal of the essence of the Machine (acoustic levitator);
- the history of the Machine's appearance is entirely separated from Elizabeth Gallup’s decryption work;
- engineer Eisenhour is completely separated from the Machine.
The way ESF substituted the Machine’s purpose should be particularly emphasized. For her, it became a laughable perpetual motion machine, rather than an acoustic levitation device, the principle of which was experimentally demonstrated as early as the 1940s. Without any references to Gallup, Bacon, or Rosicrucians, and certainly not for such heavy devices as those at Riverbank...
In intelligence language, such meticulous immersion of an interesting development into deep secrecy — through its fragmentation, renaming, and dispersion of elements into different "compartments" — is referred to as “compartmentalization of information”...
As a result of this trick, if you don't know that the more truthful version of this story is described in its entirety by acoustics scientists, relying solely on Friedmans and their admiring historians of cryptography, you would learn nothing about the Baconian acoustic levitation device. For, according to ESF’s authoritative testimony, everything was different there. That ignorant “vile creature” Colonel Fabyan not only believed in the perpetual motion machine but also tried to build it at Riverbank...
Another vivid example of how deliberate lies and improvisational fabrications constantly intertwined with elements of truth in Elizebeth Friedman's recollections can be seen in this quote from her conversations with biographer Ronald Clark in 1975 [o9]. Here, the feudal conditions at the estate of the despot Fabyan, who attempted to completely control WFF’s talents, are juxtaposed with the career successes of Herbert Osborne Yardley, whom we already know:
He [WFF] finally battled it out with Fabyan and got off for France. He was commissioned but only as a First Lieutenant, and that was Fabyan's doing. Yardley who was nothing but a telegraph operator with no college education and he started off as a Major. And here was the brilliant William F. Friedman sent off as a First Lieutenant...
To immediately clarify the degree of deliberate falsehood in this brief quote, it's sufficient to note that, in reality, Herbert Yardley began his military service as a lieutenant (and ended it as a major — after more than a decade of highly successful work as a department head in the intelligence service). In the version of cryptographic history constructed by the Friedmans, however, WFF's unsuccessful start in his military career was always necessarily linked to the machinations of the despotic and ignorant owner of Riverbank.
Continuing the theme of the Friedmans' highly unflattering remarks and negativity towards George Fabyan and his Laboratories, it's fitting to quote those memories of ESF related to their extremely reluctant return to Riverbank in 1919. The reason for this was that WFF, despite intensive searches, was unable to find employment in either genetics or any other civilian specialty after demobilization (in the subsequent interpretation by the Friedmans, these failures also became the result of Fabyan’s behind-the-scenes machinations).
The episode with the “conditions of return” for the Friedmans to work in the feudal environment of the Riverbank estate is worth examining for this reason. Depending on the context or ESF’s mood at the time of writing her memoirs, there could have been two, three, four, or even five conditions. Moreover, these conditions were often significantly different.
The most plausible — because it aligns well with all other known facts — version of these conditions was recounted to Ronald Clark, the author of WFF’s biography, during his personal conversation with ESF in 1975 [o9]:
In the end we had to agree to have a meeting with him and he paid our expensés to Chicago. And he came forth with his rosy ideas as did offer us a raise, I was to have a salary too, which not flattering was still a good living salary.
So we made certain conditions, finally agreeing on this, such as
(1) we would not live on that estate, and
(2) we would have working hours like anybody else in any other business and
(3) we would have our own car and would be free to roam wherever we pleased outside of working hours.
Well, it all sounds fine and it was held to us as much as any agreement with a man iike Ceorge Fabyan could be held to.
In the unpublished, but preserved in archives, autobiography [o10] of Elizebeth S. Friedman, an attempt is made to depict this episode quite differently (as she had just described in detail the Bacon-Shakespearean delusions of Mrs. Gallup and her sponsor Fabyan):
With Colonel Fabyan importuning us by telegrams, over a period of weeks, demanding William Friedman's return to Riverbank, that May in 1919, we finally agreed to discuss re-employment with him. We made several conditions which we insisted must be met.
The first, that we should not live on the Riverbank estate.
Two, that we should be free to live our personal lives without direction or dictation from Colonel Fabyan.
And three, that we should be permitted absolute freedom to prove or disprove Mrs. Gallup's "cipher".
He quite readily, in fact too readily, we should have suspected, agreed to our conditions.
Shortly thereafter, on the following pages of the same memoir, ESF’s flexible memory prompted her to add yet another, fourth “condition of our return”:
[Later, after the Friedmans had definitively left Riverbank and were working in Washington, Fabyan sent them an important cryptographic booklet by WFF titled "Index of Coincidences."] He had indeed placed Mr. Friedman's name upon the title page. By the way, this was one of the conditions we had made on returning to Riverbank, as well as the others mentioned, namely: that anything which either of us or both of us together wrote while we were at Riverbank would be published with the correct name as author. However, as time went on, this proved to be another example of Colonel Fabyan's deceptions.
In the 1974 interview [o5], Elizebeth Smith Friedman recalled the episode with the conditions of return once again, but slightly differently. Reducing the number of conditions to just two, she developed the theme of “self-deception” regarding Gallup and the “scientific honesty” of her husband, W.F. Friedman:
In the first place, the first condition we made was that we would not live on the estate, that we were insistent that we would live in the little town of Geneva, a mile away, which we did; we did succeed in doing that.
But the second condition on which my husband was adamant was, that we would be given liberty to prove or disprove that bilateral cipher because we had come to be absolutely disillusioned with it.
The same idea — about the supposed early disillusionment of the Friedmans with Mrs. Gallup’s self-deception — also appears in the unpublished autobiography of ESF (taking the form of a “fifth condition”):
We also valiantly tried to get Colonel Fabyan to consent to some psychological tests of Mrs. Gallup. With our limited knowledge of psychology, it seemed to us that her belief in the cipher had been so great that her eyes had been influenced to see things which no other eyes could see.
However, every time arrangements had been made for an expert to come to Riverbank and proceed with such a test, Colonel Fabyan managed somehow to have the plans changed; or cancelled. Thus, as time went on, we began to be convinced that he would never fulfill his promise to permit us to "prove or disprove Mrs. Gallup's cipher".
To give readers of these memoirs a more accurate understanding of the relationship between truth and falsehood in all these versions of the same episode, two explanations are useful.
First, when the Friedmans left Riverbank again in December 1920, extremely dissatisfied with the results of their work for Fabyan, they had more than enough time and opportunities over the next ten years in Washington to “prove or disprove Mrs. Gallup’s cipher.”
It is documented that in the 1920s, when ESF wasn't heavily burdened by state duties, she attempted to become a children’s writer. Meanwhile, her husband WFF, alongside his work in the Signal Corps of the Army (which had no connection to espionage secrets), also became an official cryptographic consultant for American delegations at international communication conferences and an author of an article on codes and ciphers for the Encyclopaedia Britannica.
But despite these favorable positions and activities for publications, as long as Gallup and Fabyan were alive, the Friedmans took no steps to present the version of “their truth” about Riverbank that they would later reveal much later, in the 1950s and subsequent years. When no participants of those events would be alive to challenge or document their lies.
Secondly, returning to the topic of testing Mrs. Gallup’s actual deciphering abilities, it's essential to emphasize that such tests were indeed conducted, and repeatedly. Moreover, Elizebeth Smith Friedman herself underwent similar testing, almost as successfully as her experienced mentors, sisters Elizabeth Wells Gallup and Kate Wells.
However, about these tests, which then became a core part of Riverbank’s [o11] educational materials (largely created and signed by W.F. Friedman), ESF never provided details. Neither in her memoirs nor in numerous interviews.
But since the documents on this matter have been preserved, and cryptographic historians prefer to ignore them, it is clearly useful to delve into the details of this intriguing episode.
In 1915 (and soon with a second edition in 1917), James Phinney Baxter, a well-known American historian, politician, and public figure, published a remarkable book titled The Greatest of Literary Problems: The Authorship Of The Shakespeare Works. An Exposition of All Points at Issue from Their Inception to the Present Moment. [o12]
The most interesting feature of this substantial and very thorough book is that James Baxter, starting his research as a serious and experienced historian, initially approached Mrs. Gallup’s sensational decryptions with considerable skepticism. However, as he delved into the specifics of the material and the evidential strength of the cryptographic arguments, Bacon's biliteral cipher took one of the central places in this story.
Unlike many other supporters (or critics) of Gallup, Baxter didn't merely study the structure of Bacon’s cipher and accept (or completely reject) the results of her decryption. Instead, he decided to personally test the remarkable decryption abilities of this lady. For this purpose, he designed several genuinely sophisticated tests, which are described in Baxter's book as follows [summarizing the essence]:
The biliteral cipher has been applied by Mrs. Gallup both to Bacon's philosophical works and the plays with interesting results.
... First we will examine the adulatory address of I. M. in the First Folio of the "Shakespeare" Works.
... We now have the word "Search." If we apply this process to the entire address, we have this startling message
"Search for keyes the headings of the comedies. Francis Baron of Verulam."
. . .
It occurred to us that the best test of Mrs. Gallup's trustworthiness as a decipherer would be to enfold in the body of the "I. M. Poem" a combination of German words, and submit it to her.
We therefore had a photograph, many times enlarged, made of the poem, from which the letters were cut, and an alphabet made of the two fonts of type in which it was printed.
Though time and patience had been devoted to distinguishing between the letters t, n, e, o, u, and r, the proper ones were selected as nearly as possible, pasted upon a large sheet of cardboard, and then photographed down to the original size as found in the Folio.
This we mailed Mrs. Gallup requesting her to favor us by deciphering it. In due time we received, with an apology for her "rusty German," the following :
Search Kaiser Kultur Krieg Tod gemachten Macht ist Rachen of Verulam.
While this contained several errors, we regarded it as a remarkable exhibition of Mrs. Gallup's skill, for we found that we had misplaced some letters.
To make our test more difficult the words comprising the hidden word "Search" were left unchanged, and were followed by our strange combination of words which used up all the letters in the word "Baron" in the Folio but the last letter n.
... We then corrected the work as carefully as possible and returned it for revision. To our great satisfaction it proved to be correct, and we here give her reply:
Regarding the biliteral example I have examined the corrections and find them quite right.
Everything else being as before, it reads —
Search Kaiser Kultur Krieg und Schlachten Macht ist Recht, n of Verulam.
The quoted test from Baxter's book was the first, but not the only one he constructed to assess Mrs. Gallup’s decryption skills, and then meticulously described in his book. For our story, it's particularly important that Mrs. Gallup successfully passed all of Baxter's tests, and their educational and methodological value was duly recognized at Riverbank.
By the time Colonel Fabyan found and brought young philologist Elizebeth Smith to Riverbank in June 1916 as a potential assistant for Gallup and her sister Kate Wells, Baxter's tests were already being used there as useful educational materials.
And today, in the collections of the New York Public Library, where the Bacon-Shakespeare archive of Riverbank is stored, one can find very special sheets of these educational tests [o13]. Signed personally by Elizebeth Smith, they demonstrate how successfully she mastered the decryption of Bacon's biliteral cipher — using examples from Shakespeare's First Folio and Baxter’s tests.
From the perspective of cryptographic history, this episode from the life and activities of Riverbank in 1916 is particularly interesting and noteworthy for the following reason.
Since the groundbreaking book The Codebreakers by David Kahn, first published in 1967, which broke the walls of secrecy surrounding cryptography and essentially initiated a series of all modern publications on the history of cryptology, the situation in this branch of science has remained consistent.
Although Riverbank and Bacon-Shakespearean ciphers are mentioned in one way or another by almost everyone, from Kahn's "bible" to the present day, no work has managed to uncover information about James Baxter's monograph [o12] and his cryptographic tests.
In fact, this situation mirrors the same kind of taboo that has been established in the history of cryptology (as well as in literary and Shakespearean studies) regarding the mention of General François Cartier’s book The Problem of Cryptography and History [o14].
The reasons why such murky — and very similar to religious — taboos are established and continue to operate in science will not be discussed here. Because enough has been said about this before (see, for example, Undermining the authorities' credibility and Shakespeare as "Our Everything" [i3]).
However, to clarify the mystery of the "London Prostitutes at the Trojan War" and the reasons for other numerous oddities in Shakespeare’s play Troilus and Cressida, the taboo on Cartier’s and Baxter’s books serves as a sort of master key to the solutions.
In other words, these issues appear mysterious to science only as long as the taboo remains in place. Once it is lifted — i.e., simply ignored — powerful cryptographic arguments from the "forbidden" books of Cartier and Baxter come into play for researchers. All these arguments prove the authenticity of Bacon's secret biography encoded in Elizabethan-era books.
And once the authenticity of this document becomes an indisputable scientific fact, it will also become clear that there is actually nothing mysterious about the strangest of Shakespeare’s plays...
Additional Reading
[i1] History Science as an Art of Cutting Out
[i2] Total Hagelin, or Finita la commedia (rus)
[i3] Undermining the authorities' credibility and Shakespeare as "Our Everything"
[i4] 4in1: Mask of Shakespeare, Mysteries of Bacon, Book by Cartier, Secrets of the NSA
[i5] Ibid, chapter "Concealing the Truth"
[i6] Ibid, chapter "Bacon, Rosicrucians and Levitation"
Main Sources
[o1] Jason Fagone. The Woman Who Smashed Codes: a true story of love, spies, and the unlikely heroine who outwitted America’s enemies. New York: Harper Collins. 2017
[o2] Ronald Clark. The Man Who Broke Purple: The Life of the World’s Greatest Cryptologist, Colonel William F. Friedman. London: Weidenfeld & Nicolson, 1977.
[o3] Betsy Rohaly Smoot. From the Ground Up: American Cryptology during World War I. National Security Agency, Center for Cryptologic History, 2023
[o4] William F. Friedman and Elizebeth S. Friedman, The Shakespearean Ciphers Examined: An Analysis Of Cryptographic Systems Used As Evidence That Some Other Author Than William Shakespeare Wrote The Plays Commonly Attributed To Him. Cambridge: Cambridge University Press, 1957
[o5] Elizebeth Smith Friedman. Interview with Marshall Library Staff. 4–6 Jun 1974. Transcripts (5 Parts) Tape #5
[o6] Elizebeth Smith Friedman. NSA Oral History, Interview with Virginia Valaki. Transcripts NSA-OH-16, 11 November 1976
[o7] John W. Kopec. The Sabines at Riverbank: Their Role in the Science of Architectural Acoustics. Woodbury, N.Y.: Acoustical Society of America, 1997
[o8] Fred W. Kranz, Early History of Riverbank Acoustical Laboratories. The Journal of the Acoustical Society of America, Volume 49, Number 2 – Part I, February 1971, pp 381-384
[o9] Elizebeth Smith Friedman. Interview with Ronald W. Clark, March 25, 1975, ESF Collection. George Marshall Foundation Research Library
[o10] Elizebeth S. Friedman, “Autobiography of Elizebeth Smith Friedman – 1st Draft” (Memoir, Lexington, VA, 1966), George Marshall Foundation Research Library
[o11] Twelve lessons in the fundamental principles of the Baconian ciphers; and applications to books of the sixteenth and seventeenth centuries. By George Fabyan. Riverbank Laboratories, 1916
[o12] James Phinney Baxter. The Greatest of Literary Problems: The Authorship Of The Shakespeare Works. New York: Houghton Mifflin, 1915 & 1917
[o13] Elizebeth Smith Friedman, early decipherments at Riverbank (1916-06). New York Public Library Manuscripts & Archives Division
[o14] François Cartier, Un problème de Cryptographie et d’Histoire. Paris: Editions du Mercure de France, 1938