book cover
From FLYNN's September 22, 1928


Edited by M. E. Ohaver
Mr. Ohaver Presents Some Ingenious Solu-
tions to Previous Brain-Racking Ciphers

BEFORE taking up the new ciphers in this issue, let us first consider the solutions to those of the preceding article, published in the August 11 issue.

Crypt No. 200, by M. Walker, affords an excellent example of the message that can be broken by comparison of prefixes and suffixes. Thus the fifth and ninth groups ended with -UIX, the third and tenth began with UI-, and the tenth ended -URSN. These suggest -ING, IN-, and -IBLE, respectively, with USING as the probable meaning of TVUIX.

Substituting in UIBOONVVURSN we have IN ESSIBLE, obviously INACCESSIBLE. After this all is over but the shouting, for the rest can easily be developed in a similar manner. The translation: "Stalwart, sturdy, intrepid explorers, using alpenstocks, courageously attempted scaling inaccessible Himalayan heights."A fine crypt, this, and not too difficult.

C. E. Roe's Cipher No. 201, as you may recall, used a key word of ten letters for the ten digits, a given message letter being represented in cipher by the key letter or letters indicating its alphabetical place. The remaining letters of the alphabet were used as word spaces.

A frequency table here shows that A, B, C, E, K, L, and U, predominate. This indicates that these are letters of the key word, since space symbols would not be used as much as letter symbols. Looking for doubled letters to represent K—11 and V—22, we find LL, UU, BB, and OO, the first two of which are the most likely on account of the higher frequencies.

Of these two letters, L is followed in the cipher by A, B, C, E, J, K, M, and R; while U is followed bv E, K, L, M. P, and R. This fixes'L as J and U as 2; and further limits E, K, M, and R—which occur after both L and U—to 3, 4, 5, 6, and o, leaving A, B, C, J, L, and P from which to select 7, 8, and 9.

From frequency VK becomes T — 20—and so on. Or, thus closely determined, the key word, LUMBERJACK, may readily be found by the anagram route. No difficulty is experienced in translating with the key, since all two-letter symbols must begin either with L or U. The message: "He kept vexing me with frantic journeys hidden by quiet zeal."

Cipher No. 202 employed the subjoined key and conveyed this information: "Context, frequency, and numerical place in the vocabulary are three factors in the determination of word symbols in this type of cipher"

A—15.16.       N—32.33.       51—and        64—the
B—17.          O—34.35.       52—as         65—was
C—18.          P—36.          53—at         66—we
D—19.          Q—37.          54—be         67—will
E—20.21.22.    R—38.39.       55—for        68—with
F—23.          S—40.41.       56—have       69—you
G—24.          T—42.43.44.    57—in         70—your
H—2S.          U—45.          58—is
I—26.27.       V—46.          59—it
J—28.          W—47.          60—not
K—29.          X—48.          61—of
L—30.          Y—49.          62—on
M—31.          Z—50.          63—that

Besides solution by alphabetical approximation and context, as described in the last article, this kind of cipher offers another, and even more interesting mode of solution which will here be briefly outlined.

The method in question is based on comparison of cipher sequences, which, through the relatively small differences existing between corresponding numbers, may be assumed to signify repetitions of the same letters or words in the message.

Cipher No. 205, herewith, will serve to illustrate this method. For example, at about the halfway mark, and along toward the end of this cipher you will find the following two sequences:

The differences between numbers signifying the same letter will, of course, vary according to the size of the alphabet. Here the alphabet appears to run from about 5 up to 60. Hence, no great differences may be expected, and it may be assumed with some degree of certainty that the above two series of numbers represent the same letters.

If this is so, we know that 20 and 21 stand for the same letter. Also that 37 to 40, inclusive, likewise stand for only one letter; and so on. When two more such series overlap they may be combined. Thus 45-48 and 44-46 indicate that all numbers from 44 to 48, inclusive, signify the same letter.

No. 205 offers several such points of comparison. And it is evident that by a continuation of the process the alphabetical part of the cipher may be reduced, in effect, to a simple substitution system, and then solved by theusual methods. The vocabulary, consisting of common short words and represented by letters combined with figures, may then be determined by context.

Cipher No. 205, like No. 202, is also modeled after an old Charles I cipher. But there is this important difference. In No. 202 the alphabet runs in numerical order from A to Z, as previously shown. In No. 205, however, the series is transposed. For example, A might be represented by 54, 55, 56, or 57; B by 7, 8, or 9; C by 40 or 41; and so on.

Other ciphers on this week's bill include a clever crypt by Fred M. Holmes, and an intriguing numerical cipher by Kenneth Clear. The crypt is calculated to keep you guessing for awhile.

So look sharp, and let us know how you solved it! The alphabet in No. 204 is based on a key phrase, which you are bound to get if you solve the cipher. What is it ?

CIPHER No. 203, by Fred M. Holmes, Burdett, New York.


CIPHER No. 204, by Kenneth Clear, Winchester, Indiana.


CIPHER No. 205.