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SOLVING CIPHER SECRETS Edited by M . E . Ohaver HOW TO DETERMINE THE LITERAL KEYS FROM WHICH THE NUMERICAL KEYS TO TRANSPOSITION CIPHERS ARE DERIVED, WITH SOLUTION TO No. 115 T HE various methods of solving single and double transposition ciphers re- cently discussed in this department have so far not considered the determina- tion of the literal keys from which the nu- merical keys to these ciphers are derived. A few words on this interesting feature of the solution should therefore not be amiss. As our readers have already been in- formed, a numerical key of this type if formed by numbering the letters of the lit- eral key from / up, according to their rela- tive positions in the alphabet, taking re- peated letters, if any, from left to right. In the key w o r d C O M M U N I C A T I O N , for example, A would be numbered i. Next, since there are no B's, the two C's would be numbered 2 and y, left to right, respectively. The /'s, next in alphabetical order, would similarly be assigned the num- bers 4 and 5. The whole key, treated in the same manner, stands as follows: C O M M U N I C A T I O N 2-10-6 - 7-lJ -8 -4-3 - 1-12-5-11 -9 The preparation of a numerical key from the literal key is thus a very simple mat- ter. But the determination of a literal key from a given numerical key is not so easy. Numerous methods may be applied, de- pending upon the length of the key, letter frequencies, sequences, terminations, et cetera. But each key will present its in- dividual problems to tax the ingenuity of the solver. A good way to begin, especially with longer keys, is to find the alphabetical limits for each number. I n the above key, for example, it will thus be seen that the first key number, 2, must represent some letter between B and U, inclusive; that 10 must stand for a letter between E and X, inclusive; and so on. 2-10-6-7 - 13-8 - 4- 3 - 1 -12 -5-11 -9 B E D D G D C B A F . C E D U X W W Z W V U T Y V X W These limits will, of course, decrease as the key increases in length. But in any event, the process may be further simpli- fied by guessing one or more letters. Here, for example, looking for a probable suffix, we find that ION—probably SIGN or TION—fits like an old shoe, at the same time regulating the limits in the remaining columns as follows: 2 -10-.6 - 7-13 -»8 - 4 - 3 - 1 - 12 - 5 -11 - 9 B 0 J J T J C B A S I 0 M C K K U K D C B r D L L V L E D O E MM w M F E D F N N X A- G F E G Y H G F H Z / K G I I H I The literal key may now be further de- veloped, by trying various combinations of
Transcript of SOLVING CIPHER SECRETS - Toebes.com
SOLVING CIPHER S E C R E T S Edited by M. E . Ohaver
H O W T O D E T E R M I N E T H E L I T E R A L K E Y S F R O M W H I C H T H E N U M E R I C A L K E Y S T O T R A N S P O S I T I O N C I P H E R S A R E D E R I V E D , W I T H S O L U T I O N T O N o . 1 1 5
TH E various methods of solving single and double transposition ciphers recently discussed in this department
have so far not considered the determination of the literal keys from which the numerical keys to these ciphers are derived. A few words on this interesting feature of the solution should therefore not be amiss.
A s our readers have already been informed, a numerical key of this type if formed by numbering the letters of the literal key from / up, according to their relative positions in the alphabet, taking repeated letters, if any, from left to right.
I n the key word C O M M U N I C A T I O N , for example, A would be numbered i. Next , since there are no B's, the two C's would be numbered 2 and y , left to right, respectively. T h e / 's , next in alphabetical order, would similarly be assigned the numbers 4 and 5. T h e whole key, treated in the same manner, stands as follows:
C O M M U N I C A T I O N 2 - 1 0 - 6 - 7 - l J - 8 - 4 - 3 - 1 - 1 2 - 5 - 1 1 - 9
T h e preparation of a numerical key from the literal key is thus a very simple matter. B u t the determination of a literal key from a given numerical key is not so easy. Numerous methods may be applied, depending upon the length of the key, letter frequencies, sequences, terminations, et cetera. B u t each key wi l l present its in
dividual problems to tax the ingenuity of the solver.
A good way to begin, especially w i t h longer keys, is to find the alphabetical l imits for each number. I n the above key, for example, i t wi l l thus be seen that the first key number, 2, must represent some letter between B and U, inclusive; that 10 must stand for a letter between E and X, inclusive; and so on.
2 - 1 0 - 6 - 7 - 13-8 - 4 - 3 - 1 - 1 2 - 5 - 1 1 - 9 B E D D G D C B A F . C E D U X W W Z W V U T Y V X W
These l imits w i l l , of course, decrease as the key increases in length. B u t in any event, the process may be further simplified by guessing one or more letters. Here, for example, looking for a probable suffix, we find that I O N — p r o b a b l y S I G N or T I O N — f i t s like an old shoe, at the same time regulating the limits in the remaining columns as follows:
2 -10-.6 - 7-13 -»8 - 4 - 3 - 1 - 12 - 5 -11 - 9
B 0 J J T J C B A S I 0 M C K K U K D C B r D L L V L E D O E MM w M F E D F N N X A- G F E G Y H G F H Z / K G
I I H I
T h e literal key may now be further developed, by trying various combinations of
960 F L Y N N ' S W E E K L Y D E T E C T I V E F I C T I O N
letters in the several columns. T h u s , r j probably stands for the vowel, U, since the adjacent columns contain only consonants. Again, if 2 and 6 are given the values C and M, respectively, we have the prefix COM. T h e whole key may be evolved in the same manner.
Short keys are often capable of more than one interpretation. T h u s , the key to Cipher No. 90, of November 5, was C I P H E R . B u t one reader submitted the key D O R M E R . Both of these words give rise to the same numerical key, 1-4-5-3-2-6. And without doubt there are still other words that would do the same thing.
T o afford the reader some fun in experimenting with keys of this sort, we are offering three examples under Cipher No. 121. T h e first of these (a) may provide several answers. T h e second (b) should prove no more difficult than the example i n this article. T h e third key (c) is practically of message length, and in some ways should prove most interesting of a l l . At any rate, fans, search out these keys, and send us your findings.
D i d you get al l tangled up in last week's No. 116? Here is the solution: Q: What is a labyrinth? A: A place full of intricate windings which render it difficult to find the way between the entrance and central compartment.
No. 117, by P a u l Napier, conveyed the message, " Solving ciphers is a fascinating task." T h i s system used the well known Vigetiere square of twenty-six alphabets w-ith the numbers i to 26 down the side, and—beginning with A=ij—across the top.
E a c h pair of numbers acted as symbol for a letter. T h u s , 14-ig stood for S, found at the intersection of the 14th row and the jgth column. An interesting peculiarity of this system is that it permits a repetition of numbers in the cryptogram quite baffling to the uninitiated, perhaps, but offering no difficulty to one having the key. H o w did you make out with i t?
No. 118, double transposition cipher, used the key word S K I R M I S H — 7 - 4 - 2 - 6 - 5 -3-8-1—and conveyed the message: " F r u s trate the enemy's attempts to organize re-treat.s under cover of darkness." Through
the omission of the nul l required to fill out the last cipher group of five letters, this cryptogram formed an eight by eight square, easily decipherable by the method given last week. ^
Double transposition Cipher No. 115, of two weeks ago, used the key word F I E L D -P I E C E — 6 - 7 - 3 - 9 - 2 - 1 0 - 8 - 4 - 1 - 5 . T h e message: " Scouting planes report reenforce-ment of enemy line on five mile front extending from railway junction west to r i v e r . " T h i s cryptogram formed a ten by ten square, also decipherable by last week's method.
T u r n i n g now to this week's ciphers, t ry James McGuire 's No. 119 if you want something good, but not too difficult in a straight substitution cipher. T h e n let M r . Bel lamy keep you guessing for awhile with the apparent words I T E M , M E R I T , DAT.A,, et cetera, scattered throughout his transposition Cipher No. 120. We have a lready covered No. 121.
C I P H E R No; n o (James McGuire, Benton, Illinois).
4628164648503730582739301048482759164628 5048471710571957101710384716584048164747
19501830
C I P H E R No. 120 (Arthur Bellamy, Boston, Massachusetts).
I T E M T T I I A E S M E R I T G R O T S T A O H Z D A T A H N N A A E I S O P SCSGS W R E H P I C M T Z F O E M E I I E H S I E G A S S
C I P H E R No. 121. (a) 4 - 3 - 1 - 6 - 5 - 2 . (b) 2-8-11-6-10-5-3-9-1-7-4-12. (c) 52-21-7-8-62-27-33-53-22-1-54-35-9-37-
4 - 4 0 - 3 4 - 2 8 - 6 3 - 1 0 - 4 9 - 2 - 1 8 - 5 5 - 1 1 - 4 5 - 5 6 -2 3 - 1 2 - 3 6 - 5 7 - 2 4 - 1 3 - 2 0 - 4 1 - 4 2 - 5 - 2 9 - 5 0 - 4 3 -1 9 - 5 8 - 3 0 - 3 8 - S 9 - 1 4 - 4 6 - 4 7 - 1 5 - 6 - 6 4 - 3 1 - 6 0 -25-61-26-16-32-48-3-44-39-17-51 .
Y^Tioop 'em up, fans! Keep your answers coming. -And send in your new ciphers, too! B u t remember to include full explanations with them. T h e solutions to this week's ciphers wi l l appear next week.
Letters from cipher fans indicate that Solving Cipher Secrets is sti l l one of the most popular departments of the magazine, and is sti l l growing in the scope of its interest. A n d all of you know that the more readers who make their mterest active, the more readers there wi l l be to enjoy the department to the full.
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