Cryptology A Puzzle from a Children's Magazine

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The Cryptogram

Here is an example of cryptanalysis by pattern search. I found the ciphertext in a puzzle magazine for children a long time ago. It caused some headaches even though addressed to children—until it fell into my hands recently and I tried pattern search on it.

The text was printed as some funny picture symbols and illustrated with the picture of a cheerful mountain climber. (Unfortunately I threw away the magazine and only kept the cryptogram transcribed as letters. Therefore I cannot retrace a possible solution by replacing each symbol with its initial letter.) The text transscribed as random letters looked as follows:

  ABC DBEFGHIJKII IJBGLG MEF LGHEG BNO POEG QBFGHICKEF

From the context we guess that this is a monoalphabetic cryptogram. Also the frequency count supports this assumption:

The multiply occuring bigrams are:

The text being quite short there is no hope to crack it by a purely statistical approach. Neverthless we conjecture that G = e, and {B, E, I} is a subset of {n, i, r, s, a, t}.

Pattern Search

The text apparently shows the word boundaries. Therefore we try to find complete words in the dictionary.

The second word DBEFGHIJKII yields the hits Handelsguss, Spitzenmann. Both of them are impossible because the third word begins with IJ. Long words in German often are composed, this gives virtually infinitely many possibilities that are not contained in any dictionary. Not discouraged we search at least for words ending in IJKII, and get the following hits:

tritt, suess, (lvoll,) stoss, (lfell,) (nsinn,) (sguss,) smass, (sfuss,) (lball), (lfall,) spass, (nmann,) ertee, (snuss), rherr, saess

We have another long word to search for, QBFGHICKEF. The dictionary provides several hits:

  abdichtend, Ausgleichs, Autodienst, Bankfirmen, Blumenfrau,
  boesartige, breitmache, Buecklinge, Dankopfern, dienstbare,
  entspricht, Fangquoten, farbigster, farblicher, Farbumkehr,
  Finderlohn, Fischtrans, foermliche, Folterqual, Frauenliga,
  Freistunde, freudigste, freundlose, Fundsachen, gaenzliche,
  Gaskochers, Goldanteil, Grenzwache, Gutschrift, Haeftlinge,
  Haeufigste, haeufigste, Halswirbel, Inspektors, kaergliche,
  kaeufliche, Karolinger, Kinodramen, klebrigste, koernigste,
  Korbmacher, Kunstorgan, Landwirten, mischbares, Mondphasen,
  Mondschein, muendliche, noerdliche, Nordischer, normalster,
  nuetzliche, Ranglisten, Rangstufen, Ruecksitze, rundlichen,
  saemtliche, sorglicher, Stechpalme, Stecklinge, Steinkohle,
  Sterbliche, suendhafte, Taeuflinge, tuerkische, unhoeflich,
  unscharfes, unsoziales, unterzogst, verwundbar, Vokalmusik,
  Waschkorbs, Waschtrogs, Widerstand, widerstand, Windharfen,
  Windpocken, woertliche, Wohlgeruch, wuerzigste, Wunderplan,
  Wundsalben, Zielpunkte, zornigster, Zuschlages.

dienstbare, Halswirbel, Widerstand, widerstand.

Solution

Let's enter our findings into the cryptogram:

  ABC DBEFGHIJKII IJBGLG MEF LGHEG BNO POEG QBFGHICKEF
   it  inders ass s ie e und  erne i     ne widerstand

Now we look again at the hits for second word and see that spass fits. This suggests J = p, and then we guess the words spiele und lerne, and then the complete solution:

  Mit Kinderspass spiele und lerne ich ohne Widerstand