AS an improvement upon transposition ciphers using a series of exactly similar transposition cycles, E. Myszkowski offers in his Cryptographie Indéchiffrable—Paris, 1902—a cipher in which the transposition cycle becomes as long as the message itself.
The Myszkowski system is based upon a numerical key, which is formed upon a literal key derived in turn from a word key agreed upon by the communicating parties. To illustrate the system, the message, SEND REINFORCEMENTS, will here be enciphered, using the key word REDAN.
Having first transcribed the message (c) in as many lines as its length may require, the key word is next written letter for letter above it, repeated as many times as necessary, and forming the literal key (a).
Should it happen in any case that the length of the key word is evenly divisible into that of the message, so that the last letters of the key word and message fall together, one or more nulls, at the discretion of the encipherer, must be added at the end of the message before enciphering. Such nulls were unnecessary in the present case, the key word having been used three full times with a remainder of three letters, R-E-D, for the last letters of the message.
The literal key (a) is now transformed into a numerical key by numbering the letters in alphabetical order from 1 up, taking repeated letters from left to right. Here, for example, the A's are numbered 1, 2, and 3, left to right; the D's 4, 5, 6, and 7; and so on, forming the numerical key (b).
This done, the letters of the message are transposed by rearranging them in the order (d) indicated by their individual key numbers, Myszkowski writes his cryptogram continuously, using a numerical prefix— "18" in this example—to indicate the number of letters in the message. If desired, this prefix may be omitted, and the message may be grouped by fives, DFMNN ESEIC TROES ERN, in the usual manner.
(a) r e d a n r e d a n r e d a n r e d (b) 15 8 4 1 12 16 9 5 2 13 17 10 6 3 14 18 11 7 (c) s e n d r e i n f o r c e m e n t s (d) 18.d f m n e s e i c t r o e s e r n
The receiver of the cryptogram prepares a numerical key of the indicated length; and numbering the letters of the cryptogram serially from 1 up, restores them to their original order by merely rearranging them in the order designated by the numerical key.
In enumerating the merits of this cipher, Myszkowski points out that it is not too complicated to be practical, and that it is quite undecipherable, no two messages of different lengths being transposed in the same order even with the same key word.
Nevertheless, the system can be deciphered without the key, and exactly the same order of transposition can be effected by a much more direct method which will be fully described next week. In the meanwhile, fans, see what you can do with Mr. Winsor's No. 70, below. This specimen was actually enciphered by the improved method to be given next week. But it may be treated as if it had been done exactly in accordance with Myszkowski's directions.
Did you succeed in building up the key phrase to cipher No. 61 (J. Levine), published in the August 27 issue?
Key phrase: A quick movement of the enemy would jeopardize six gun-boats.
Message: A sentence containing all the letters of the alphabet is used to encipher this message.
As you may remember, each letter of the message was represented in cipher by the two letters before and after it in the key phrase. Thus, the symbol for Q would be AU; that for U would be QI; and so on. Letters repeated in the key phrase would have more than one substitute. For example, E is variously represented here by VM, MN, HE, EN, NM, JO, and ZS. In some keys the same symbol might stand for different letters. Here OT stands for both F and A; and NO for T and B.
The solution to last week's No. 65:
Question: What was the French cabinet noir?
Answer: An office created during the reign of Louis XV where the letters of suspected persons were opened and read by public officials before being sent on to their destination.
As to No. 66, the colors of the stones, paired off, become substitutes for letters in accordance with the following alphabet, where DD equals A; DG equals B; and so on:
D G B Y P
(drab) D A B C D E
(gray) C F G H IJ K
(brown) B L M N O P
(yellow) Y Q R S T U
(pink) P V W X Y Z
Substitute in this alphabet and you get the message: IF YOU WOULD HAVE MY FORTUNE DISCOVER THE HIDDEN PAPER. In this way the stone wall pictured in the issue of August 20, and explained last week, would have conveyed three different and altogether independent messages, depending upon the shapes, sizes, and colors of the stones.
This week's ciphers begin with another of the "Q. and A." variety in No. 68, after you have solved which you may be willing to believe almost anything.
No. 69 is an original cipher submitted by a fan who is anxious to see his system put to the test. And accordingly a longer time is being allowed before publication of the answer.
Just a word, in this connection, about reader ciphers. Any cipher which you would like to have the fans try out should be accompanied by its solution and explanation. The "test" period will be adjusted to suit the difficulty of your problem. But the solution is necessary so that the cipher can be explained in a subsequent issue.
If you have already submitted a cipher without its explanation, you may send the latter in now, if you wish, calling attention to your previous letter. All communications should be signed with your full name and address. But your name will be withheld from publication if you prefer.
CIPHER No. 68.
Question: PDT ORK RKB ORG PRAX KWKX IWAXL ? Answer: HW OCA TGL JVQTA YVRJL; GHC OGA TGL WHJ YVIJ ZWTCJ ATGH HW OGA; ATJKJIWKJ, GHC OGA TGL HVHJ YVRJL !
CIPHER No. 69 (Myer Stine, Los Angeles, California).
Store No. 1 Store No. 2 Store No. 3 Store No. 4
$.60 $5.60 $3.00 $5.00
5.00 13.50 8.20 11.00
1.30 9.00 .50 9.00
2.00 13.00 13.50 ———————
5.00 10.21 .70 $25.00
11.00 1.00 5.00
5.70 13.60 8.00
.21 ——————— ———————
——————— $65.91 $38.90
$30.81
CIPHER No. 70 (Charles Winsor, Boston, Massachusetts).
RISEE ATFAP IEVAF TPRNN
AEREE RHTTR RHHAO RSCVI
FONYE IETTS ENGSH ODRHO
OOPNE ITITS AOHCI RTCP