NO doubt you have on many occasions observed the odd looking groups of letters, figures, or other symbols, used by shopkeepers in marking the prices of their merchandise. But perhaps it has never occurred to you that they had any connection whatever with ciphers.
Nevertheless, such devices are legitimate cryptographic systems, and in them will be found many methods of encipherment known to ordinary ciphers. In fact, the main difference between price mark ciphers and those of the ordinary run lies in the nature of the intelligence to be communicated.
In the ordinary cipher, for example, the message is expressed in the letters, words, et cetera, of some language. In the price mark cipher the "message" is the cost or selling price of merchandise, expressed in an "alphabet" made up of the ten digits.
Of the numerous types of price mark ciphers, those based on substitution principles are the most widely employed. Some systems, however, utilize mere transpositions of the figures, such as writing them backward, or otherwise changing their order. Other systems use nulls, usually figures, intermixed with the significant figures. Sometimes two or more of these principles will be found in the same system, just as they are combined in ordinary ciphers. Representative examples of these various types will be given in subsequent articles.
A common type of price mark cipher, however, is one of the simple substitution variety in which a word or phrase of ten different letters is used as a key to the ten digits. For example, with BLACKSMITH as key we would have B=1, L=2, and so forth, as shown below. With this key an article costing two dollars and fifty cents would be marked LKH; and so on.
1 2 3 4 5 6 7 8 9 0 B L A C K S M I T H
It was a price mark system of this kind that proved to be the undoing of a New York City clothing merchant during the World War. Government agents on the lookout for profiteers happened to notice a raincoat priced by this dealer at an exceptionally high figure.
Suspecting that all was not as it should be, they worked out the key—which turned out to be "God help us" (X for zero)—and found that the price asked for the article was out of all proportion to its cost. Faced with the evidence, the shopkeeper was so distraught that he shot himself to death, a tragic finale which had by no means been anticipated.
Despite the fact that ciphers of this kind are easy to solve, you will, nevertheless, find them in use at every turn. In fact, almost any shop window will provide material for an interesting problem in decipherment.
In Cipher No. 159, herewith, we are offering you a bona fide price mark cipher of this type. The cost prices are given in cipher above the line, and the selling prices in ordinary figures below the line. See if you can discover the word or phrase used as key. Methods of solving the cipher will be given next week.
Besides No. 159, this week's bill also includes interesting ciphers by L. J. Talbot and Philip J. Crotty. Mr. Talbot's is a straight substitution cipher, and his first contribution. Welcome to the mystic circle, L. J. Let us hear from you often! Mr. Crotty's cipher is easy to use and remember, but will probably prove difficult to solve without any hints.
As crypts come and go, we venture to say that most of you found last week's No. 155, by Mrs. M. L. Fowler, somewhat of a sizzler. Of course, if you were lucky enough to get the first part, the translation of the second part would necessarily follow, even though the two parts used different simple substitution alphabets. But we'll wager that this one stopped more than one persistent fan, anyway.
Question: FOUR THOUSAND SIX HUNDRED SEVENTY-TWO PLUS THIRTY-ONE EQUALS WHAT ? Answer: FORTY-SEVEN HUNDRED THREE.
The answer to C. E. Roe's "limerick crypt," last week's No. 156, is next in order. This cipher was intended more to show you a good time than to present any particular difficulty in solution. Several other exceptionally interesting crypts and ciphers by Mr. Roe will be published in forthcoming articles.
Miranda, who lived in Antigua,
Remarked to her spouse, "What a pig you
are!"
And he said, "O my queen,
Is it manners you mean.
Or do you refer to my figure?"
No. 157, Dr. Ferrell's numerical cipher, was a digraph system in which each pair of numbers represented two letters of the following message: "A long message like this could be solved by digraphs, but without the rule a short message would be quite difficult."
To encipher, take the message by twos (a) and substitute in a straight 1-to-26, A-to-Z alphabet, as shown at (b). Next, transform the simple substitution cipher so obtained into a digraph substitution cipher by taking the sum and difference of the numbers in each pair, placing the sum under the larger of the two numbers, and the difference under the smaller, as at (c). Finally, regroup as at (d), to conform with normal word divisions.
(a) A L O N G M E S ... (b) 1 12 15 14 7 13 5 19 ... (c) 11 13 29 1 6 20 14 24 ... (d) 11—13.29.1.6—20.14.24. etc.
In deciphering, take one-half of the sum and one-half of the difference of the pairs of numbers (c) and you will obtain the pairs at (b), which, by simple substitution, gives the message (d). Once the secret to a system like this is exposed, it can, of course, be easily solved. The trick lies in penetrating the method of encipherment.
CIPHER No. 158 (L. J. Talbot, Detroit, Michigan).
WILY KYAINWD: HMAD VAOMIY AD ZQ KAYDH LHHIZOH DC OJIL- DI WCNH UI HCC MLYW CN ZI.
CIPHER No. 159.
CTWR OWW DWW WNW —————— —————— —————— —————— $32.50 $4.50 $8.00 $9.00 XEWR DOW CWR OER —————— —————— —————— —————— $17.50 $4.00 $2.75 $4.50 XTWR IWR —————— —————— $15.00 $10.00
CIPHER No. 160 (Philip J. Crotty, Charlestown, Massachusetts).
ALJ FTH BWO UJB GHO BIT
CBS VTP ERN ZYA ZEP PSE
ARO UEN JOT SFX TRK LAN
IWG EZR THS ZIN NOG SSF
APF IPE IFA RHW