
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].
4
(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.
4
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].
10