Fermat's Library | Frank Miller: Inventor of the One-Time Pad annotated/explained version.

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The 1882 monograph that Steven Bellovin (author of. this paper) stu...

**Superencipherment** generally means encrypting an already encrypt...

Part of the reason for the poor cryptography was the relative perio...

### Vignère cipher The Vignère cipher is an encryption method t...

After the assassination of Lincoln, a handwritten Vigenère square w...

#### Stager's cipher Stager's cipher was a route transposition cip...

An optical telegraph is a line of stations, typically towers, for t...

William Frederick Friedman was a US Army cryptographer who ran the ...

Frank Miller: Inventor of the One-Time Pad

∗

Steven M. Bellovin

Department of Computer Science

Columbia University

http://www.cs.columbia.edu/

smb

CUCS-009-11

Abstract

The invention of the one-time pad is generally credited to Gilbert S. Vernam and Joseph O. Mauborgne. We

show that it was invented about 35 years earlier by a Sacramento banker named Frank Miller. We provide a tentative

identiﬁcation of which Frank Miller it was, and speculate on whether or not Mauborgne might have known of Miller’s

work, especially via his colleague Parker Hitt.

1 Introduction

One-time pads are in theory the strongest possible algorithmic cipher: if the key is used properly, they cannot be

broken, even in theory. The invention of the one-time pad is generally credited to Gilbert S. Vernam of Bell Telephone

Laboratories and Joseph O. Mauborgne of the U.S. Army Signal Corps [29, 60]. Vernam invented a device that would

exclusive-OR keystream bits from a paper tape with the Baudot code generated by letters typed on a keyboard; he

and Mauborgne realized that if the keystream tape characters were (a) perfectly random, and (b) never reused, “the

messages are rendered entirely secret, and are impossible to analyze without the key” [60]. (To be sure, others have

made similar assertions about their ciphers; Vernam and Mauborgne’s claim has the advantages of being both correct

and mathematically provable.)

In fact, they were anticipated by about 35 years. In 1882, a California banker named Frank Miller published

Telegraphic Code to Insure Privacy and Secrecy in the Transmission of Telegrams. In it, he describes the ﬁrst one-time

pad system, as a superencipherment mechanism for his telegraph code [42]. If used properly, it would have had the

same property of absolute security.

Although in theory Miller can claim priority, reality is more complex. As will be explained below, it is quite

unlikely that either he or anyone else ever used his system for real messages; in fact, it is unclear if anyone other than

he and his friends and family ever knew of its existence. That said, there are some possible links to Mauborgne. It

thus remains unclear who should be credited with effectively inventing the one-time pad.

We start by describing and analyzing Miller’s codebook. We then explain our tentative identiﬁcation of the author,

and speculate on possible linkages to Mauborgne.

2 The State of 19th Century Cryptography

It is worth discussing common 19th century cryptography, to better understand Miller’s starting point. The state of the

art, at least in the United States, was very poor [14, Lecture V]. Broadly speaking, two principle systems were in use,

straight-forward ciphers and superenciphered codes. Both were rather simple. (For further background, also see [62]

and [63].)

∗

Note: this is a preprint copy of a paper that has been submitted for publication. The ﬁnal form may vary signiﬁcantly.

During the Civil War, the Confederacy primarily used a Vign

ere cipher (which they often called a “court” or “diplo-

matic” cipher) [49], via manual tables [14, Lecture IV]. A Vign

ere square was also used by John Wilkes Booth and

others in their plot against Lincoln. The Confederacy often used meaningful phrases as high-level keys; in February

1865 they switched to “Come Retribution” from “Complete Victory” [59].

The Union employed a cipher disk to implement an easy-to-change monoalphabetic substitution. The key — that

is, the rotation — could be changed in mid-message, or by switching disks. It also employed Stager’s route trans-

position cipher [29, 49, 63], which combined a codebook for (many) proper names with a word-based transposition.

(An advantage of transposing words, rather than characters, is that it allowed telegraph operators to correct many

transmission errors.)

Codebooks were certainly not new. In some form, they go back to the optical telegraphs of the 18th century [57];

superencipherment goes back to the very ﬁrst telegraph codebook, compiled by Smith in 1845 [54]. His codebook

represented each word as a letter/number pair. He described using an additive to provide conﬁdentiality, and even

described using different additives for different codewords:

For instances, instead of conﬁning the pre-agreements of the parties, to the deduction or addition of one

number only, let one number be agreed on, for every alternate word sent in ﬁgures, and another number

for every other word; or, by the same rule, let several numbers be used for addition or deduction, in any

order that may be agreed on.

In addition, he suggested the use of a monoalphabetic substitution of the code letter.

Few late-19th century codebooks were much better at superencryption. The 1899 U.S. War Department code

[25], though intended primarily for administrative use, did provide for superencipherment; it was less sophisticated

than Smith’s. It suggested adding or subtracting a “key number or series of key numbers”, and gave as examples

the sequence “25, 50, 75, 100”. It did, however, note that “the use of 50 or 100, while easy to remember, should be

avoided”.

One well-known codebook stood out. Slater’s Telegraphic Code, to Ensure Secresy in the Transmission of Tele-

grams [sic] [52] talked about simple additives, but he also described a variety of more complex transforms. For

example, he suggested transposing digits in code numbers, or regrouping the 5-digit code numbers into 4-digit ones.

In addition, he suggested using combinations of these methods. Despite its limitations, Slater’s codebook became the

basis of a War Department code [14, 63]. (Curiously, Friedman’s discussion of Slater’s superencipherment focuses

only on the use of additives, and misses the more complex transformations [14, p. 96].)

None of these schemes were that sophisticated. Friedman conjectures that European cryptanalysts were able to

read American State Department correspondence with little trouble.

3 Miller’s Codebook

Miller’s codebook has two independent components, a conventional telegraph code intended for message compression

and a superencipherment system. The telegraph code is conventional for its time: it mapped phrases into both English

words and 5-digit code groups. While an 1882 codebook cannot be rated against the very sophisticated works produced

in the 1920s and 1930s, it does not appear to be a particularly good compression system even when ranked against its

peers. Contrast a page from Miller’s book (Figure 1) with one from Bloomer’s 1874 codebook (Figure 2), another one

intended to provide conﬁdentiality [19]; in general, Miller maps a single plaintext word into a single codeword, though

there are glaring exceptions such as the entire paragraphs that are represented by FESTIVAL or FESTIVITY, while

most of Bloomer’s code words represented phrases. (Bloomer also understood security better than most. Although

he did not carry out the work himself, he apparently recognized the virtue of two-part codes; the book provides

instructions on how to generate one and blank columns in which to write alternate code numbers.)

One of Miller’s codewords, GUINEAPIG, is interesting both because it shows the limitations of the code but also

for what it says about authentication over the years:

Figure 1: A sample page from Miller’s codebook. Note the general lack of compression; most codewords, with a few

exceptions and a few glaring exceptions, represent a single plaintext word rather than a phrase.

‘

Figure 2: A sample page from Bloomer’s codebook. The blank columns permit conversion into a two-part code.

Figure 3: Blank codewords, for use with a particular correspondent.

Mother’s maiden name, that old standby “secret”, was used that way at least as early as 1882.

Note, though, that there is a crucial security failure here: that codeword, suitably shifted, is to be followed by the

secret, and the secret almost certainly has to be in plaintext: there won’t be a codeword for most family names. The

appearance of something that looks like a family name and is a word not in the codebook would quite likely be of

interest to any eavesdropper. The alternative is using codewords to spell out the name, but that will result in a large

expansion of the message and hence an increase in cost. This, of course, is a failure mode of all codebooks, not just

Miller’s, but it does show the limitations of Miller’s code for one of its intended purposes. (We note that the 1899

Preliminary War Department Telegraphic Code [25] included codewords for all ofﬁcers then in the Army, to avoid

precisely this problem.)

Miller’s codebook was not as easy to use as some. It mostly lacked subject divisions; encoders would have had to

ﬁnd each phrase alphabetically, and perhaps guess at precisely which word the phrase was indexed under. A clerk who

is experienced with a given codebook would be less inconvenienced; this, however, creates a bias in favor of sticking

with more familiar works. (Familiarity can help. Lord Nelson’s famous signal “England expects that every man will

do his duty” originally started “England conﬁdes that. . . ”. However, his signal ofﬁcer pointed out that “conﬁdes” was

not in the codebook, and hence would be slower to send, whereas “expects” was. Nelson agreed to the change [24].)

Given the poor compression and usability, and given that telegraph codebooks are subject to a network effect — a

codebook owned by many recipients is more valuable to a sender than one owned by just a few — we suspect that it

was little-used in practice. The problem was likely exacerbated by a lack of marketing: Miller had a full-time job as a

banker, and probably couldn’t spend his time persuading other banks to use his code book. As in so many other ﬁelds,

marketing is extremely important when selling codebooks [29, 30].

One unusual feature of the codebook does warrant further attention. As with virtually all codebooks, this one

has blank positions for user-supplied plaintext; see, for example, the middle section of Figure 2. Miller, by contrast,

provided about 20 pages of pair-wise lists of extra words; each such page was intended for correspondence with a

different individual (Figure 3). This clearly shows his orientation towards point-to-point communication, rather than

one-to-many or many-to-many. Any realistic use of one-time pads would indeed require point-to-point messaging. A

broadcast scenario, where one party sent to multiple others, would require everyone to have a receive-only list; Miller

does not describe any such thing. Given the lack of broadcast transmission media then, this is not surprising.

Miller’s superencipherment, by means of additives and modular arithmetic, is much more interesting. As noted

earlier, additives were well-known. Miller, however, identiﬁed the essence of the one-time pad: randomness and

non-repetition [emphasis in the original]:

A banker in the West should prepare a list of irregular numbers, to be called “shift-numbers,” such as 483,

281, 175, 892, &c.

The differences between such numbers must not be regular.

When a shift-number has been applied, or used, it must be erased from the list and not used again.

A copy of the list is to be sent to the New York Banker, who prepares a different list and sends copy

thereof to the Western Banker.

It seems clear that Miller understood the threat he was countering: “Any system which allows a cipher word to be

used twice with the same signiﬁcation is open to detection. A little talk with a telegraph operator will convince one of

this fact.” One can, of course, question how deep his understanding was of the cryptanalytic threat, but it’s hard to be

clearer than that in a single sentence.

Is this a true one-time pad? Kahn deﬁnes such a system as one consisting of “a random key used once, and only

once” [29, p. 398]. That Miller understood the “once, and only once” part is clear. But is “the differences . . . must not

be regular” equivalent to “random”? We submit that it is. He stressed the phrase, showing that he thought patterns

were a serious, exploitable ﬂaw. It would have been nice, though, if he had explained techniques for generating the

additives, and if his samples had not all been 3-digit numbers. (According to Kahn, Vernam and his colleagues used

“characters drawn from a hat” for keying material.)

Miller also thought about the threat model. He suggested that messages that could be sent verbally by a messenger

need not be encrypted, though he also noted that as a practical matter not many people in a town would possess the

codebook. Even then, however, he realized that messages needed to be authenticated, even if not encrypted. To this

end, he provided a list of 100 “test words”; a sender would take the next available shift-number modulo 100 and use

that to select the appropriate test word. The receiver would verify the test word against his list of shift-numbers; both

parties, of course, would cancel that value. Miller does not seem to have considered that a telegraph operator could

substitute a different message to one protected by a simple authenticator, nor does he mention that receivers must be

properly trained to insist that all messages be authenticated. By contrast, Slater’s authentication codebook recognizes

both problems [51, pp. 4-5]:

In very many cases, however, and it is surprising in how many, the receivers of messages purporting to

come from some well-known correspondent, take it for granted that every telegram which so reaches their

hand must be genuine, and, without further consideration of the consequences, act upon it.

. . .

There still remains, however, the possibility of a fraud being committed, as it were, over the blank signa-

ture of the sender, by a dishonest servant who may be entrusted to carry to the telegraph ofﬁce the message

it is intended to transmit, inasmuch as he would have it in his power to substitute another message drawn

up in his own interests and certiﬁed by his master’s test, or to interpolate some additional words of his

own.

and

Nothing then is easier for a dishonest cable operator than the commission of a fraud of gigantic extent.

The concept of the test word as a message authenticator appears to have been relatively new to telegraphy at the

time. “Test word” itself appears to have been a reasonably-common 19th century phrase for actions or writing designed

to prove something or someone authentic or genuine. The Freemasons are claimed have employed a secret test word

[18, p. 86], as did the Templars [21, p. 122] and the Ku Klux Klan [15, p. 24]. (Though [18] and [15] are works by

outsiders attacking the Freemasons and the Klan, that does not affect our point: both works use the phrase “test word”

without further explication, buttressing our assertion that readers were familiar with the concept.) The earliest use we

have found in telegraphy was just six years before Miller, by Slater [51]; in essence, he suggests use of a book code

to authenticate messages. He also gives a number of variants to protect the date, word count, etc. Interestingly, he

suggests using sentences; this way, a missing word can indicate that a particular message was never received. Miller

put the phrase “test word” in quotes, as if his audience might not be familiar with it in this context. It is unclear if

Miller was familiar with Slater’s book (which was much less well known than his secrecy code [52]). While we do

not know if Miller was a member of any quasi-secret fraternal organization, he was an ofﬁcer of the Grand Army of

the Republic [47], a Civil War veterans’ association which is said to have used Masonic rituals [33] and certainly kept

them secret [17].

Use of test words in telegrams did become commonplace later on. Lieber [41] references the phrase, though

without explanation. [22, p. 155] describes how Wells Fargo used test words on internal telegrams. By the time of

World War I, test words were sufﬁciently common that there were special provisions in the censorship regulations to

accept such words that were not in the standard codebooks [13, p. 40]. A banking textbook [40, p. 170] gives a detailed

explanation of how test words are added and veriﬁed by a special department in the bank.

Checksums appear to date from the same period as Miller’s book. For example, during an 1881 meeting of the

Royal Astronomy Society, Lord Crawford said [48, p. 170]

Mr. Ritchie opened a communication with me a short time ago, with a view of introducing a method,

which he and Mr. Chandler had contrived, for the despatch of astronomical information of interest.

By this method the elements and the ephemeris, which are comprised in twelve lines of printing, were

transmitted in sixteen words on a cipher telegram. We cannot go wrong in the telegram, because one

test-word checks the whole message.

The full scheme was published a few years later by Chandler and Ritchie [20].

For all its cryptographic sophistication, we doubt that Miller’s superencipherment system was ever used in prac-

tice: there are some serious operational deﬁciencies. The most important is the lack of any indicators to show where

in the shift-number list the sender started; the scheme as described assumes that all messages are delivered, received,

and decrypted in order. This is not a realistic assumption; a high-priority telegram composed late in the day would

arrive before a “night letter” composed earlier. Real-world one-time pads generally use something like a page num-

ber/additive number pair to show where to start decrypting. There is one nod in that direction — the codeword

PECCADILLO means “For this and all other dispatches from us we beg that you will use ‘shift-numbers’ from our

list commencing next below Number ” — but that is rather clumsier than using indicators routinely.

There are also two codewords to deal with a shortage known to one side but not the other. PEBBLES means “send

more shift numbers”; PECANA means “No shift numbers here available, so use the ‘plain cipher’ [the codebook

without superencryption] or English”. However, the sender’s list has to be in synchrony with the receiver’s; one side

can’t run out without the other knowing it [61]. Possibly, the intent was to deal with exception cases, such as loss

or compromise of an additive list; if so, one would expect special codegroups to indicate the problem, and most like

coupled with the “send more” message.

4 Who Was Frank Miller?

It is difﬁcult, at this remove in time, to be certain just which Frank Miller developed the one-time pad system. (To

avoid confusion, in this section we will refer to the author of [42] as the “compiler”, and reserve the proper name

“Frank Miller” for a particular historical ﬁgure.) That said, there are enough clues that — aided by happenstance —

we have come to a strong, albeit not certain, conclusion. We believe that the compiler is the Frank Miller who later

became the president of the National Bank of D.O. Mills & Co. in Sacramento, as well as one of the founding trustees

of Stanford University.

The codebook itself offers a few concrete details. The copyright page identiﬁes the compiler as living in Sacra-

mento. In the preface, he describes himself as having “sixteen years’ banking experience”. Sixteen years before the

publication date was 1866, immediately after the U.S. Civil War ended; this would be a logical time for a young man

leaving the army to have started a permanent job. It also seems likely that the compiler had at least some acquaintance

with cryptanalysis.

The population of Sacramento was not large at the time, probably around 35,000–36,000 given the 1880 and 1890

census ﬁgures.

There were 14,526 males over 21 years old in 1880, reducing the set still further. (That ﬁgure was not

collected in 1890.)

Data retrieved from the University of Virginia Library Historical Census Browser, http://mapserver.lib.virginia.edu/.

Figure 4: Frank Miller in 1896. (Picture taken from [47],

from an electronic copy held by the University of Michigan

Digital Library.)

We know that there were not many banks in Sacra-

mento then [16, 64]. Conceivably, of course, some-

one could have worked at other banks before moving

to Sacramento; that said, a Frank Miller who did start

at a Sacramento bank in 1866 would very likely be the

person we are looking for. Assorted Internet searches

turned up a published genealogical history [50] that de-

scribes a person with precisely those characteristics; ex-

cept as otherwise indicated, the biographical informa-

tion in the remainder of this chapter is taken from it.

(The other valuable source was a brief 1896 biography

of Miller in Overland Monthly [47]. To modern eyes,

that one starts strangely, addressing him as “Comrade

Frank Miller” and describing him as coming from “good

old revolutionary stock”, phrases we would regard as

more apt for a descendant of a veteran of Mao’s Long

March than for a California banker.) Additionally, cen-

sus record searches via www.familysearch.org

show just two Frank Millers in Sacramento in 1880;

one worked at the D.O. Mills bank and the other was

a “laboror” [sic].

Frank (or Franklin) Miller was born in Milwaukee on

18 January, 1842, the son of Henry and Nancy Robinson

Miller. His family moved to Sacramento in 1856 [50]

or 1857 [47] (though [1], an obituary for his father from

the Sacramento Record-Union, says 1850). He attended

Phillips Academy in Exeter, New Hampshire, enrolled at

Yale in 1861, and enlisted in the Second Wisconsin Vol-

unteer Infantry regiment in 1862. He fought at Antietam

and was wounded at the Second Battle of Bull Run.

In 1863, Miller, by then a sergeant, was transferred

to clerical duties in the Inspector General’s ofﬁce. The

following year he was “promoted to a civil clerkship” in New York [47] working for Colonel Henry Steel Olcott, a

prominent investigator of fraud and corruption during the Civil War [43, 58].

Olcott offered to assist in investigating

Lincoln’s assassination; Secretary of War Stanton replied, “come and bring your force of detectives” [23, 43]. He was

apparently effective, being described as “the most conscientious member of the investigative team” [32]. Miller ap-

parently came with that “force of detectives”, though we do not know what his role was. We suspect that it was during

the 1863-1865 period, investigating various crimes and peculations, that Miller became acquainted with encryption

and perhaps cryptanalysis.

Miller’s father was the founding vice president of the D.O. Mills bank; Frank Miller was the “cashier”. On

his father’s death in 1878 he became vice president; he became president in 1893 when Edgar Mills, the founding

president, died. Miller retired as president in 1904 [3]. After that, he was no longer resided full-time in Sacramento;

he and his wife traveled a great deal and resided in a number of different places before settling down in Berkeley in

1910 or 1911. He and his wife moved to the Pendleton Hotel in San Francisco in 1905 [34] after spending a year or

so in Europe; they moved to Sausalito for the summer of 1906 [35] and ended up staying there [37], probably because

The census record for the banker Frank Mills at

https://www.familysearch.org/s/recordDetails/show?uri=http://pilot.familysearch.org/records/trk:

/fsrs/rr_206956290/p_334654861&hash=HloWXpZgU9zB10k5M56iYku8TUc%253D shows a birth year of 1850, which is

inconsistent with other sources and difﬁcult to reconcile with Civil War service. The other data listed agree so well with [50] that we suspect an

error in the record or in its digitization.

Olcott himself had a very colorful career. After the war, he became a lawyer. He grew interested in spiritualism, converted to Buddhism, and

was one of the founders of the American Theosophical Society. Most of the published information on him concentrates on his religious career.

of the 1906 earthquake and ﬁre. Fortuitously, that move took place a few days before the quake [36]. He did plan to

return frequently to San Francisco; he was one of the guests of honor at a banquet scheduled for 20 April 1906 [5], and

he and his wife had purchased opera tickets for the forthcoming season [8]. They also returned to Sacramento often

[4, 6, 7, 36], as well as traveling to Oregon where Miller had signiﬁcant business interests [3].

We know little of Miller as a person. Examination of his correspondence to and from the president and trustees

of Stanford University [2, 9] suggests that he was a forthright, blunt, almost brusque individual; he concluded more

than one letter with “do not bother to answer this” or similar words. Another letter, evaluating a proposed personnel

policy, concluded with “He is not so competent, nor is any other man.” He resigned as a trustee in 1916 — a post that,

from his resignation letter, he valued highly — because of ill health [9] and failing eyesight [50]. His relations with

one of his sons was strained, apparently over ﬁnancial issues but with the sense that he thought this son was rather

irresponsible.

At some point, the compiler acquired an interest in communications. The codebook’s preface quotes a “Colonel

Myers” [sic] on the value of cryptography; this is Albert J. Myer, the father of the U.S. Army Signal Corps, and the

quote is slightly paraphrased from from Myer’s classic work “A Manual of Signals” [45]. (Myer is also considered

the father of the Weather Bureau; as a result, he was sometimes known as “Old Probabilities” [63].) It is worth noting

that the passage does not appear in the 1864 version of the Manual [44], the only one Miller might have seen while in

the service; it does appear in the 1866 and later editions. It is unclear whether an ordinary soldier would have known

of or remembered Myer, or been familiar with that book; someone who had worked in intelligence or cryptanalysis

almost certainly would. Myer was reasonably prominent after the war, though; it is conceivable that the 1879 edition

[46] — the ﬁrst to be issued by the Government Printing Ofﬁce — or Myer’s death in 1880 stimulated the creation of

the codebook.

We suspect that the compiler did not have hands-on experience as a code or communications clerk or as a crypt-

analyst; such a person would have been more familiar with indicators, message serial numbers, telegrams being sent

out of order, etc. On the other hand, the preface does discuss common transmission errors on telegraph systems (e.g.,

confusing some Morse symbols with others). It was comparatively unusual to see such discussions in codebooks of

that era; this may indicate more than usual familiarity with telegraphy.

It is fortunate indeed for our research that Frank Miller was a prominent person. He was sufﬁciently important that

he was one of the original trustees of Stanford University and left a considerable paper trail, including coverage on

the Society pages of the San Francisco Chronicle. Even more important, his descendants preserved information about

him and someone compiled it all [50].

5 Linkages

The compiler of this codebook — we are certain that it was this Frank Miller — clearly developed the one-time pad;

his inﬂuence on history, however, is much less clear. It is much like the old philosophical conundrum of a tree falling

in a forest with no one around: does it make a sound? Did Vernam or Mauborgne ever learn of Miller’s work? Again,

there are no ﬁrm answers; the best we can do is to speculate.

We can almost certainly rule out contact with Vernam [31]. Vernam was an electrical engineer whose specialty

was the encryption hardware; he was not a cryptologist. Kahn concluded long ago that Mauborgne, not Vernam,

had the essential cryptologic insight on non-reuse of keys; see the endnote discussion about the development of the

non-repeating key for a Vernam machine in [29].

There was not much more chance of direct contact between Miller and Mauborgne. Mauborgne was not stationed

in San Francisco until 1932 [55], well after the period of interest. He did pass through the port of San Francisco en

route to the Philippines [11], but any encounter with Miller would have been pure coincidence. There does, though,

appear to have been one possible opportunity. Mauborgne’s ship was scheduled to sail on November 5, 1913; there

was a large ball to open the Portola Festival on October 23, and ofﬁcers were invited [12]. However, we have not found

any evidence that either he or Miller attended it. Neither is in the attendee list given in [10], though that article lists

people who were “among the invited guests” [emphasis added]. Furthermore, a quick scan of the Society columns of

the San Francisco Chronicle shows very few mentions of Miller after 1910.

A more intriguing possibility is contact between Miller and Parker Hitt. Hitt, an expert cryptologist and the author

of Manual for the Solution of Military Ciphers [27], was Mauborgne’s mentor and colleague. In 1914, he took a major

step towards development of the one-time pad when he wrote “No message is safe in the Larrabee cipher unless the

key phrase is comparable in length with the message itself” [29]; his ﬁrst observations along that line were presented

a few years earlier at an Army Signal School Technical Conference [28].

(The text makes it clear that he was worried

about Kasicki superimpositions in what was essentially a Vign

ere cipher, rather than any more general principle. The

text also notes that multiple encryption with keys of different lengths is not that strong, either; this was later relearned

by Vernam and Mauborgne.) Kahn has conjectured that this observation resulted from joint work with Mauborgne;

again, see the endnote discussion mentioned above. It is quite clear that if Hitt knew of Miller’s system, he would have

shared the information with Mauborgne when they were together at the Army Signal School in Fort Leavenworth.

Crucially, it is virtually certain that Miller and Hitt did meet, and under circumstances where the codebook could

very easily have come up in conversation. Hitt was stationed at the Presidio in San Francisco February–July 1906;

according to his diary, he did attend a number of social functions during that time [26], though we do not know if

Miller was at any of them. More importantly, Hitt and Miller both attended “the most brilliant military ball which

San Franciscans remember to have seen in many years” [38]. This party was hosted by “the bachelor ofﬁcers of the

Twenty-Second Infantry”, including Hitt. The hosts “received the guests at the entrance to the hall, then escorting

them to the ladies of the receiving party”. Given that this was a party by “bachelor ofﬁcers”, and given that Miller and

his wife were accompanied by their daughter Edith, it is hard to imagine that Hitt and Miller did not talk. Edith would

have been regarded as highly eligible; she was 25, single, an “unusually attractive, charming girl” [39] (also see her

picture at [50, p. 445]), a former Stanford student, and from a prominent, well-to-do family. She may herself have

been looking; marriages to ofﬁcers of that regiment were regarded as quite desirable [39]. Indeed, six months later she

married another ofﬁcer listed as a host, Lieutenant Matthew H. Thomlinson [37].

Given this, we are convinced that Miller and Hitt at least exchanged greetings and probably chatted more. Fur-

thermore, given that the ball was partly to celebrate the ﬁrst anniversary of the regiment’s return from the Philippines,

we assume that Miller asked Hitt about his activities there. As it turns out, among other activities Hitt had set up

communications lines. He was also very interested in telecommunications [56]. Had this come up at all in conversa-

tion, it strikes us as highly probable that Miller — a man who was interested in the subject, and knew of and quoted

Myer’s book — would have recounted his own efforts in the ﬁeld. But Miller was brusque; it is also easy to imagine

that his manner in speaking could have put off Hitt, who could easily have treated this as an amateur giving advice on

telecommunications to someone who had done it in the real world.

Speculation can only take us so far. Simply mentioning authorship of a codebook, or even a codebook and su-

perencipherment system, is very different from trying to explain shift-numbers at a party. Based on the evidence

available thus far, we cannot quite conclude that Hitt knew enough about Miller’s system to have been inﬂuenced by

it. Conversely, of course, we also cannot conclude that he was ignorant of it. Perhaps one aspect — keying material as

long as the plaintext — stayed with him and inﬂuenced his comments about the Larrabee system.

Our overall verdict is “not proven”. For effective transmission to have happened, Miller would have had to tell

Hitt of his idea in some detail. Hitt would have had to retain enough memory of it to use in in formulating his maxim

about key length, but not enough to actually credit Miller. Thus, though Miller’s idea may have lived on, if so it it was

via a subconscious channel, and almost certainly through Hitt. (We also note that Mauborgne told Kahn that he came

up with the idea himself while working with Vernam [29].)

Drawing any further conclusions will be difﬁcult unless more documentation is unearthed. Hitt’s papers have been

scrutinized by many historians; they are unlikely to hold any surprises, unless there are cryptic references to Miller

that would have been meaningless without the context supplied here. Miller’s papers and diary may hold clues; they

existed at least as late as 1987 [50], but we have been unable to locate them. (Neither of the two obvious repositories,

Stanford University and the California State Library, has them.) We leave these matters to other historians who are

more diligent, or who have access to resources that we do not.

Kahn had speculated that Hitt formulated this precept before 1914. Research by Craig Bauer and Drew Wicke of York College of Pennsylvania

and John W. Dawson, Jr., retired from Penn State University at York, has conﬁrmed this. However, the note is by Hitt and Lieutenant Karl Truesdell,

rather than with Mauborgne. Truesdell compiled the ﬁrst set of multilingual frequency for the U.S. Army [29].

6 Conclusions

It is clear that Miller invented the one-time pad: res ipsa loquitur. His work was remarkable, not just because he

invented a secure encryption scheme 35 years before it was reinvented, but also because it came out of the blue.

Vernam and Mauborgne were working in the ﬁeld; Vernam was trying to build a secure communications system and

Mauborgne was the head of research and engineering for the U.S. Army Signal Corp. They were the sort of people

one would expect to invent such a thing. Miller, on the other hand, was a banker, whose only ﬁrst-hand experience

with cryptology (if any) was likely 16 years earlier. Still, he was not the ﬁrst amateur to make a signiﬁcant contribution

to the ﬁeld. Indeed, Kahn has a chapter entitled “The Contribution of the Dilettantes”. The most remarkable tale in

that chapter is that of Thomas Jefferson, who invented a wheel cipher in the 1790s, an invention that was promptly

forgotten and not rediscovered in his papers until 1922. Ironically enough, Jefferson’s cipher was reinvented a few

years before that by French cryptologist

Etienne Bazeries; it was brought to the U.S. and reﬁned by none other than

Parker Hitt and Joseph Mauborgne.

One can also speculate on the risks of tying a bad system — the conventional codebook Miller authored — to

a good one. Had Miller published — and marketed — his superencipherment independently from his codebook, it

might have succeeded. Robert Slater’s codebook [52], intended only for conﬁdentiality, was even worse than Miller’s

for compression (though it had 25,000 words, compared with Miller’s 12,800); despite that, the work went through

nine editions, the last published in 1938 [53], and even was the basis for a U.S. government codebook [14, 63]. The

difference was likely marketing — Slater was secretary of the French Atlantic Telegraph Company —but regardless,

Slater’s work survived and was inﬂuential; Miller’s work has been forgotten.

It is tempting to speculate on how history may have been different had people paid attention. Almost certainly,

one-time pads would never have been employed for most military communications; the operational difﬁculties, then

as now, would have been prohibitive. But what of high-level diplomatic correspondence? Kahn tells many tales of

cryptanalysis of such messages between 1882 and 1918; might things have been different? Might the German Foreign

Ministry been able to protect Zimmernan’s fateful telegram with a one-time pad if they had known of Miller’s work?

And if so, would the U.S. have entered World War I when it did? History might not have been changed — years later,

the Japanese used their PURPLE machine for diplomatic messages, rather than a Vernam machine — but perhaps it

might have been.

Finally, it takes nothing away from Vernam or Mauborgne’s own creativity to acknowledge that Miller had the

same idea. If nothing else, their system — an online, automated mechanism that operated on the 0s and 1s of Baudot

code — was far more usable and was the precursor to today’s computerized stream ciphers.

Acknowledgments

As always when we are doing historical research, we must ﬁrst thank the generations of librarians and archivists who

have collected, indexed, and preserved crucial documents over the decades. At least as important, they help me ﬁnd

obscure materials. We are especially indebted to the staffs of the Library of Congress (where we ﬁrst found Miller’s

book), the Columbia University Library Network, the Stanford University Library, and the California State Library.

Google Books also deserves a mention for its role in making many rare works easily available.

William Shurtleff’s genealogy book was an extremely valuable resource; his private comments were also helpful.

I had limited time to travel; I was aided in “remote research” by Roy Frostig of Stanford University.

Craig Bauer and Drew Wicke of York College of Pennsylvania and John W. Dawson, Jr., retired from Penn State

University at York found Hitt’s paper at the Army Signal School Technical Conference, conﬁrming Kahn’s opinion on

when the observation on key length was made, but also showing the context of that opinion.

We have received a lot of useful information and guidance from many historians, most especially Betsy Rohaly

Smoot of the NSA Center for Cryptologic History, David W. Gaddy, and Dr. Edgar F. Raines, Jr. and Rebecca Robbins

Raines of the U.S. Army Center of Military History. Norman Polmar of the U.S. Naval Institute and David Kahn also

provided very important advice and pointers. Errors, of course, are all ours.

One should not draw the conclusion that Hitt was a habitual plagiarist who stole from both Miller and Bazeries. Kahn quotes Hitt’s memo as

explicitly crediting Bazeries for the wheel cipher.

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The Preface to Miller’s Codebook

**Superencipherment** generally means encrypting an already encrypted message one or more times either using the same or a different algorithm. After the assassination of Lincoln, a handwritten Vigenère square was found in John Wilkes Booth’s (Lincoln's assassin) hotel room. ![](https://i.imgur.com/cSugMZM.jpg) *Vigenère square by John Wilkes Booth’s* Part of the reason for the poor cryptography was the relative period of pease the came after the American civil war. For decades there was little or no need for cryptology in the United States government, except for the communications of the Department of State. An optical telegraph is a line of stations, typically towers, for the purpose of conveying textual information by means of visual signals. The Semaphore Optical Telegraph was invented by the Chappe brothers in France in 1792. Claude Chappe, the primary inventor, first called this device a tachygraph, ‘that which writes fast.’ ![](https://i.imgur.com/2CaSfuE.jpg) *Signalling by semaphore in 18th-century France* ![](https://i.imgur.com/IgdiSR2.png) *Development of the Chappe Network of optical telegraphs in France* The Baudot code is an early character encoding for telegraphy invented by French engineer. J. M. E. Baudot in the 1870s. In Baudot code each character is alloted five units, or pulses. Each unit consists of either an electrical current or its absence in a given time. It was the predecessor to the International Telegraph Alphabet No. 2 (ITA2), the most common teleprinter code in use until the advent of ASCII. ![](https://i.imgur.com/mMVtWQR.png) *Baudot Code* The 1882 monograph that Steven Bellovin (author of. this paper) stumbled across in the Library of Congress: ![](https://i.imgur.com/3i0ieQb.jpg) *Telegraphic Code to Insure Privacy and Secrecy in the Transmission of Telegrams* William Frederick Friedman was a US Army cryptographer who ran the research division of the Army's Signal Intelligence Service (SIS) in the 1930s. In a lecture on the topic of cryptography in America in the period he states: > in Europe more complicated cases were often solved, and I imagine that European cryptanalysts could have read, and perhaps did read, State Department messages as a more or less routine matter. I think I am warranted in assuming that what I have just said is true because, in Europe, cryptanalytic studies were going on apace during the years of American neglect of such studies. The turning point from neglect to a renaissance of interest in cryptographic studies in Europe is said by some One-time pads are "information-theoretically secure" in that the encrypted message provides no information about the original message to a cryptanalyst (except the maximum possible length of the message), irregardless of the computational power under their control. #### Random Number Generators Generating truly random numbers turns out to be a fairly hard problem. The ability to generate randomness is essential to areas such as computer simulation and cryptography. There are two principal types of random numbers: - **Pseudo-random numbers**: These are generated based solely on deterministic logic. In other words, computational algorithms are used to produce long sequences of apparently random numbers, which are in fact determined by a short initial value know as seed. These are appropriate for applications that only need a modest amount of unpredictability (e.g. Random Fact of the day). - **"True" Random numbers**: These are produced by measuring some physical phenomena that is recognized to be random. Example sources include atmospheric noise, cosmic background radiation and radioactive decay. ### Vignère cipher The Vignère cipher is an encryption method that relies on a series of interwoven Caesar ciphers, based on the letters of a keyword. It was actually first described by Italian cryptographer Giovan Bellaso in 1553, but it was misattributed to French diplomat and cryptographer Blaise de Vigenère. #### Caesar cipher In a Caesar cipher, each letter of the alphabet is shifted along some number of places. For example, in a Caesar cipher of shift 3, A would become D, B would become E, Y would become B and so on. ![](https://i.imgur.com/L36uCQl.png) *Caesar cipher of shift 3* Here is an example: ``` fermat ------ ihupdw ``` The **Vigenère cipher** has several Caesar ciphers in sequence with different shift values. To encrypt, a tabula recta (aka Vigenère square) can be used. It has the alphabet written out 26 times in different rows, each alphabet shifted cyclically to the left compared to the previous alphabet, corresponding to the 26 possible Caesar ciphers. At different points in the encryption process, the cipher uses a different alphabet from one of the rows. The alphabet used at each point depends on a repeating keyword (which you can think of as the key). In other words, for encryption you can just use the corresponding letter of the plaintext and the keyword as coordinates in the Vigenère square and that will give you the corresponding ciphertext. ``` fermat ------ runrun ------ wyedug ``` ![](https://i.imgur.com/9kMmvME.png) #### Stager's cipher Stager's cipher was a route transposition cipher, whereby words are reordered according to a predefined route. It was invented by Anson Stager who worked at the Western Union Company. Here's an example of how it worked. Let's say the message you want to transmit the following message: *"Let's meet tomorrow after school at the park to play baseball."* 1 - **Replace important words (such as places, people, events and times.) with code words** ``` Baseball = soccer Park = bridge After school = morning Tomorrow = Monday ``` Now we have: *"Let's meet Monday morning at the bridge to play soccer."* 2 - **Make a route cipher** To make a route cipher, you need to put your message in a table. The sample message above has 10 words. Your grid can have spaces for more words than your message, but not less. You can pad the blanks with "null" or meaningless words (e.g. umbrella, cat). You can make a grid for 12 words: four across, three deep. ![](https://i.imgur.com/YbLpYw4.png) 3 - **Decide on a route to use in your cipher** The simplest route path is to go down each row in order instead of across. Your message now becomes: *"Let's at play meet the soccer Monday bridge umbrella morning to cat."* More complicated ways of traversing the table are entirely possible and would make it even harder to try to decrypt the message.

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