BEFORE beginning the week's cipher department it might be well to remind readers who have lost copies of FLYNN'S WEEKLY DETECTIVE FICTION containing Solving Cipher Secrets that back numbers can still be purchased by writing the publishers at 280 Broadway, New York City. But now go on with the interesting variations that phonetic alphabets bring to cryptography.
The purpose of cryptography is to transform or disguise a communication so that it will be meaningless without the key. And this statement holds good regardless of the alphabet or system of characters in which the communication may have been originally expressed.
Hence, the use of phonetic alphabets is entirely legitimate for cryptographic purposes. Further, such systems are practicable, for phonetic alphabets can easily be adapted to existing methods of encipherment.
For example, last week's Cipher No. 145, by M. Walker, was a phonetic cipher employing the simple substitution principle. That is, a given phonetic character in the alphabet used was represented at each occurrence by the same cipher symbol; and, conversely, a given cipher symbol always signified the same phonetic character or sound.
This week we shall offer a multiple alphabet system..And for this purpose the forty-character phonetic alphabet given last week is here arranged in a diagram of eight rows and five columns, numbered for use with a key word in the manner of the Nihilist cipher.
In this system any phonetic character is signified by the numbers indicating its row and column. Thus, K, which is in the fourth row and second column, is represented by the symbol 42. In the same way, U—short U—is represented by 74; M bv 44; and so on, as shown herewith where the message COME AT ONCE—KUM AT WUNS—has been enciphered with the key word TRAIL—TRAL.
(a) K U M A T W U N S (b) 42 74 44 11 72 82 74 45 65 (c) T R A L T R A L T (d) 72 64 12 43 72 64 12 43 72 (e) 114-138- 56- 54-144-146- 86- 88-137
The message is shown phonetically spelled at (a), with numerical equivalents at (h). Key characters are written below those of the message in line (c), with their numerical equivalents in line (d). The completed cipher (e) is obtained by adding the numbers in lines (b) and (d). In deciphering this system with the key, the process just described is merely reversed. The key numbers are written in rotation beneath the numbers of the cryptogram so that each cipher number will have a key number. The key numbers are then subtracted from the cipher numbers, and phonetic values are substituted from the diagram for the differences so obtained. The message is then divided into words.
Cipher No. 148, below, will afford the reader an opportunity to solve this cipher without the key. And in this connection it may be said that the present system can be resolved by the same methods used for the Nihilist cipher with a 5 x 5 key in the ordinary alphabet, as described in the June 27, 1925, issue of this magazine. Due allowance must be made, of course, for the differences caused by using eight figures instead of five in the key.
But the application of the above method to the present example will reveal the length of the key and nearly half of the key numbers in just a few minutes. The rest of the key will also be indicated within certain limits, which can be rapidly narrowed down by context. Remember, in solving this cipher, that in a phonetic alphabet each character fixedly represents one sound only. In the above alphabet, as explained last week, the long vowel sounds and diphthongs are given in italics to distinguish them from the short vowels.
Cipher No. 147, in this issue, is another example of a phonetic system by M. Walker submitted in response to our call of several weeks ago for speaking or pronounceable ciphers. This cipher, as our correspondent put it, "offers no difficulty to a cipher fan, but it is sufficiently difficult to balk the curiosity of the landlady who likes to read your diary while she rests a few minutes after ridding up your room, or that of the bird who reads over your shoulder in the car the notes you write in your memorandum book."
A well-known jingle has been used for text. And Mr. Walker calls attention to the fact that encipherment has neither hurt the meter nor made the rime any worse than it was in the original. This system can, of course, be used with prose as well as poetry, and in either case it creates the illusion of a foreign language. Can you decipher it?
Last week's straight substitution cipher, No. 143, conveyed the message: "The predominating symbol does not always stand for E in this kind of cryptogram." Did the single-letter "word" and the low frequency of E in this cipher throw you off the track? Another cipher of this type, No. 146, is offered in this issue.
Cipher No. 144, by Philip J. Crotty, conveyed the text: "Cipher Fans: I too am a cipher fan and hope you enjoyed deciphering this." Grouping was arbitrary, and substitutes were found by counting forward in the alphabet as many places as there were letters in the message up to and including the group being enciphered, deducting 26 whenever the count was in excess of that number. Each punctuation mark restored the count to zero.
Thus, the first group of four letters, CIPH, was enciphered by taking the fourth letter in advance for each letter, GMTL. The next group of three, ERF— seven letters in all—similarly became LYM by counting seven letters in advance; and so on. Mr. Crotty says he would like to correspond with any one interested in cryptography. His address is 10 Prospect Street, Charlestown, Massachusetts. Drop him a line.
The answers to Cipher No. 146 and Mr. Walker's phonetic Ciphers Nos. 145 and 147 will appear next week, the latter with complete alphabets. The answer to No. 148 will be published in two weeks.
CIPHER No. 146.
OTDOLWHJGFOCH FCKCD WGPC JIC WGF PX DTSIJ EIX PTPF'J PX DTSIJ TP HYTJC XQ JICW.
CIPHER No. 147 (M. Walker, Akron, Ohio).
ORT NUHUL QUUPALT YEMD DU HI GUPULT DU KED QUUL BUL TAK E POM. QUYEM ZWI KAD HAL HI GUPULT YAS PAL AMT ZO HI BUL TAK QUAT MUM.
CIPHER No. 148.
65-125-70-108-113-108-107-137-42-137-79- 68-135-86-107-99-46-96-117-85-105-48-85- 137-54-78-89-37-136-55-94-146-94-117-97- 56-136-58-107-76-115-87-117-58-156-106- 103-130-103-77-89-47-97-106-77-87-83-134- 68-49-137-58-87-137-106-117-79-108.