Results of the fourth Fahrenheit211 cryptanalysis competition.


I must admit that the puzzle I set this time around was an absolute blinder. Nobody cracked this code at all and bearing in mind that it was a three source book-code cryptogram I’m not at all surprised.

Here’s the original ciphertext followed by the translation and an explanation of how the cryptogram was worked out.

First the original encrypted text

1285234    253513    34422    1364144
253411   2372222    385128    3118115    137815

125529   1375216    368122    37126    249925

2314226   398221

313211 356127 255815 36415 1282113

1375216     329127     3851258     232523

238712    2401215

136412     1362237      310616     36527
331213     2561216     2435113

249925    2314226    382223     1254253
330115    36421    244611    250922    2554214

253513    2354217      249925    1287128     1293143

325231 1287128 2436116 241113 2373117
384213    32813     125124

3105216     3118215     3118122     2298213
1363110    255916    1320134     365114

325231    240510     311818    2432214    1257239
3133112    326121    1354234

1362237   2388212    2561216    2551212    2551112

3102211   235129    1297147   126625

Now we have the plain text message that was encrypted to read as above

We few, we happy few, we band of brothers. For he today that sheds his blood with me shall be my brother; be never so vile. This day shall gentle his condition. And gentlemen in England now abed shall think themselves accursed they were not here, and hold their manhoods cheap whiles any speaks that fought with us upon Saint Crispin’s day.

From Shakespeare’s Henry V

Now we have the method by which the above text was encrypted

To avoid too any repetitions, which can give major clues as to the message structure and content, three source code books were used. I used English/Latin, English/German and English/French dictionaries but I only used the ‘English’ sections of these dictionaries. The use of dictionaries ensures that nearly every word you could possibly want is included in the source code book They were: Cassell’s Compact Latin/English Dictionary originally published in 1963 (Source 1), Larrousse’s French/English dictionary published 1971 (source 2) and Cassell’s compact German/English dictionary published 1970 (source 3) The ‘source number’ is given in brackets after each title.

The cryptogram is structured as follows

Take the first crypto word, 1/285/2/34 broken down into discreet sections as an example. The first figure is the number given to the source books in this case source ‘1’. The second figure to the right of that number, the number ‘285’, refers to which dictionary page is being used. The third figure ‘2’ refers to the column on page in source book ‘1’. The fourth figure ’34’ is the number of words from the top of the column, in this case the word ‘we’.

It was a very interesting puzzle to put together and one that people have found fiendishly difficult to solve. This sort of encryption is time consuming and labour intensive but it is pretty secure provided that the source code books are not disclosed. It isn’t I have to say as secure as a ‘one time pad’ system, but this particular book-code system shows that a considerable degree of message obscuration can be achieved with the right choice of source code books, with the more obscure the books chosen, the better the security.