[JoGu]

Kryptologie

The Dancing Men

Die Kryptogramme / The Cryptograms
a7Hzq .#5r<
k\as TK$
j(2 w%h:
k{4R f~`z8
+ &D

The first four messages that Holmes used for his successful cryptanalysis:

[Message 1]
[Message 2]
[Message 3]
[Message 4]

Then came message number 5 that Holmes could read almost immediately:

[Message 5]

And this was his answer that trapped the bad guy:

[Message 6]

Let's translate the symbols into simple letters (and the flags into spaces, as Holmes concluded immediately); then the messages look like this:

AB CDED AFD GHAIDJ
AKDHELMDG
NOBD DHGLD
IDPDE
DHGLD QEDQAED KO BDDK KCJ MOR
NOBD CDED AK OIND

Cracking this cipher after the first four messages was by no means trivial; the amount of cipher text was simply too small. The word boundaries that, as Holmes immediately noted, were marked as little flags in the hands of the dancing men were of little help. So was the letter e.

Since we have electronic means at our fingertips, let's use them. A dictionary search for message #4, the one word message IDPDE gives 561 hits. If we assume (as Holmes did) that the most frequent ciphertext letter D represents the plaintext letter e, then 156 hits remain, of which never is virtually the most probable word.

With message #5 we have more luck: The word QEDQAED only gives 4 hits, and prepare seems to be the best. However Holmes had already broken the cipher when message #5 arrived.


Author: Klaus Pommerening, 1 November 2007; last change: 13 November 2007.