book cover
From FLYNN's June 23, 1928


Edited by M. E. Ohaver
The Porta Cipher of Last Week Is Solved, With an Interesting
Explanation — Also, Other Solutions and New Ciphers

IN the Porta multiple alphabet system described last week you no doubt observed that all the alphabets were exactly alike in their first lines. Through this peculiarity the table employed by this cipher can be arranged in the more compact form shown herewith , without changing the results in the slightest degree.

    a b c d e f g h i j k l m
AB  n o p q r s t u v w x y z
CD  o p q r s t u v w x y z n
EF  p q r s t u v w x y z n o
GH  q r s t u v w x y z n o p
IJ  r s t u v w x y z n o p q
KL  s t u v w x y z n o p q r
MN  t u v w x y z n o p q r s
OP  u v w x y z n o p q r s t
QR  v w x y z n o p q r s t u
ST  w x y z n o p q r s t u v
UV  x y z n o p q r s t u v w
WX  y z n o p q r s t u v w x
YZ  z n o p q r s t u v w x y

The first, or A-to-M, line, common to all the alphabets, is here placed across the top of the table. And the second lines, beginning successively with each letter of the series N-to-Z, form the square, key letters at the left.

In this condensed table, any given alphabet consists of its proper line in the square used in conjunction with the A-to-M line, letters in the same column acting as substitutes for each other. In the "MN" alphabet, for example, A stands for T, and T for A; B for U, and U for B; and so on. Each alphabet operates in like manner.

Last week's Cipher No. 187 will illustrate the use of the table. The key to this cipher, NAPLES, is repeated, as at (a), above the message (b), so that each message letter is provided with its own key letter. Cipher substitutes (c) are then found in the table as just described.


Thus, C enciphered in the N-alphabet becomes V; I in the A-alphabet is also represented by V; and so on. In translating, the key letters are written above those of the cryptogram, and the message letters are found in the table just as in encipherment. Translation in full of No. 187 is as follows: "Ciphers are twofold in nature, serving both to conceal and to reveal the messages conveyed."

The above cryptogram provided a number of clews to aid in its solution. Thus, the repeated group, AB, at the interval of twelve letters, could be in - terpreted as probably indicating a key of 2, 3, 4, 6, or 12 letters.

In the Porta system, message letters and their cipher equivalents must be in different halves of the alphabet. Hence, AB would probably signify no, so, to, up, us, on, or or. And each of these possibilities could be tried in running down the key.

A quicker solution, however, presents itself in the group MZT, which by the rule just mentioned is the only three-letter group in the cryptogram which could stand for the. This supposition would give three alphabets, OP-KL-EF, of the unknown series.

And application of these alphabets at the intervals named above would indicate a six-letter key by affording the following probable translation at six - letter intervals: -phe-- -re t---old," and so on. By development this becomes, "Ciphers are twofold," etc., and the whole translation is soon before us.

Each alphabet in the Porta system answers to two key letters. Hence, it often happens that a given cipher can be produced by more than one key word. Here, for example, the six alphabets MN-AB-OP-KL-EF-ST have been used. Examination of these letters will show that either MAPLES or NAPLES could be the key. The latter , however, was the one actually used.

Last week's crypt. No. 185, by J. Lloyd Hood, dealt with a long word, in question and answer form: What does philoprogenitiveness mean? Instinctive love of offspring." This crypt affords another interesting example of solution by analysis of suffixes.

Thus, the terminal -UCOO is probably -ness rather than -less on account of the relative frequency of the symbol U. Comparison with this would give -ing for -DUY. Substitute in the sixth group, DUOMDURMDFC, and you have ins-in--i-e, which easily becomes instinctive, unlocking the rest of the cryptogram.

David M. Raymond's concealment cipher. No. 186, used the numerical key 4-312, the 4 indicating the number of nulls at the beginning of the cipher and the number of letters in the significant groups, and the other figures showing the order and length of the nonsignificant groups.

Using capitals for the nulls, and lower case italics for the significant letters, this cipher becomes: WTAZ-numb-TLK-erth-M-reer-TL-epor-CHI-tsth-E-atou-RA, and so on. Divide the four-letter groups into words and you have the message: "Number Three reports that our cipher has been discovered. See me at once." Did you solve it ?

In the first of this week's ciphers. No. 188, you have a crypt of more than ordinary interest. The text is free from obsolete, or other unusual words.

The author of No. 189 says that her cipher has never been solved. Never-the-less, we believe that some of our fans are going to get it. Just wade in and let us know the casualties.

No. 190 is another Porta cipher, but this time without the normal word divisions . We believe, however, that the suggestions offered in connection with No. 187 should also pave the way to a speedy solution of this example.

Answers to this week's ciphers will be published next week. In the mean-time solve what you can and submit your answers. The next solvers' list will appear in an early issue. Watch for it !

CIPHER No. 188, by M. Walker. Akron, Ohio.


CIPHER No. 189, by Mrs. M. B. Parran, St. Leonards, Maryland.

6.  Guvf  flfgrz  vf  rnfl  gb  qrpvcure  vs
htq  wqm  ug  wbckb,  nih  u htubw  htzh  uh
ltww  cdi  zp  pyha  ltisdji  ti.  Lp  sykp
kion  sj  gksjo  x  ysj,  xdn,  ie  pxh,  rxlo
oflez  ef  fen  aqf  yfluz  kiwejuwkn  rk.

CIPHER No. 190.