Tuesday, July 09, 2013

The Dorabella Cipher (Part 1)

Below, in Figure 1, you can see the famous Dorabella Cipher, which Edward Elgar wrote to Miss Dora Penny 1897.
Figure 1. The Dorabella Cipher (1897)
You can read more details about the background of Elgar, Penny and their families in the linked wikipedia article.

What makes this cipher so special is, that it was send from Elgar (who liked to play around with ciphers and word puzzles) to a Lady, which did not have any particular background or interest in ciphers. They only met a few times and still Elgar was sure that she could somehow decipher his message.

During the years there were several proposed solutions for the cipher, but none of them got accepted by the community as being correct. It is assumed that it is a simple monoalphabetic substitution cipher and it has not been solved because of the short ciphertext, which neglects attacks based on letter frequencies.

So far, there is only one solution which seems somehow promising to me (Tim S. Roberts, Solution). It is because of the very meaningful recovered plaintext, but it still contains some really strange inconsistencies and doubtful steps. There are many websites that discussed his solution and i will not restate any of them here.

The symbols used in the Dorabella Cipher reminds one of a Pigpen Cipher. And this theory could be supported with some further hints:

The E-like symbols from the Dorabella Cipher also appear in some of Elgar's notebooks, see for example Figure 2. You can see, that Elgar is playing around in order to find a suitable letter-to-symbol configuration. On the bottom left you can see circles with a cross in it and those little marks at eight distinct positions.
Figure 2. Notes from Elgar (from 1920?) where he plays around with the same symbols.
This looks very much like a Pigpen Cipher approach to arrange symbols in a certain way to find a easy to recognize mapping from the alphabet to the cipher symbols. He also used the symbol-to-alphabet mapping, that is shown in the top left, to encode three messages on the page:
  1. "MARCO ELGAR" (the name of his dog)
  2. "A VERY OLD CYPHER"
  3. "DO YOU GO TO LONDON"
In the 3. message, some symbols seem to be quite wrong or at least ambiguous, if we assume that he really wants to encode "DO YOU GO TO LONDON" as written in plaintext on the right side. And I have no clue why he adds the word "TOMORROW" on the right. Note that these notebook entries are made 23 years after the Dorabella cipher. Perhaps he was trying to remember his method.

Elgar used three different types of cipher symbols and each one could be oriented in eight different directions, thus in total 24 possible symbols. As usual, see also Figure 2, the letters I and J as well as U and V are combined to reduce the alphabet from 26 to 24 characters.
Figure 3. A Pigpen circle and a possible symbol mapping.
For such a Pigpen circle, there are \(2^8\) ways to orient the little marks on that \(8\) segments, either on the left or on the right side of the corresponding line. In Figure 3, you can see a possible configuration of the Pigpen circle. Since Elgar drew such circles several times, it is possible that he also used such circles for the Dorabella Cipher.

But even if he used this circles as the base for his Pigpen Cipher, in what order did he assign the letters to the circles segments? And did he used the same Pigpen circle for all 24 symbols or do they differ for the three different symbol types? Or did he somehow encoded all 24 symbols in one such circle? The last question is backed-up by the fact, that there are exactly 24 little lines on that circle. So each such line could represent a symbol rather than three of them.

This approach was also taken by Tony Gaffney and produced the, so called, Hellcat Solution.
Figure 4. Tony Gaffney's Pigpen circle for his solution.
The outcome is the text:

"B Hellcat ie a war using effin henshells! Why your antiquarian net diminuendo? Am sorry you theo o’ tis god then me so la deo da — aye"

I can not believe that this is the correct message, although i like the approach using this particular Pigpen circle.
Surprisingly, in 1885, already a decade before writing the Dorabella cipher, Elgar used these symbols to make an annotation against a couple of lines of music.

Figure 5. Elgar's annotation from 1885.
You have to rotate the page about 90 degrees clockwise in order to read the cipher symbols correctly as done in Figure 6.
Figure 6. Rotated annotation text. Known as the "Liszt Fragment".
The Pigpen circle that Elgar used for this ciphertext is nowhere shown. This fragment became known under the name Liszt Fragment. Tony Gaffney suggest for this one to use a similar Pigpen circle as for his Hellcat solution, that produces the plaintext:

"Mes it's one Frn seezhup"

Other annotations or pieces of text along the music lines in his notebook are said to be something like "Very good performance", "slightly out of tune", "poor", "beautiful", "I think you know this a little", "very well done august" and so on. Why should he wrote the itself rather cryptic sentence "Mes it's one Frn seezhup"? And why would he encrypt an musical annotation at all while leaving many others in plaintext?


3 comments:

  1. .... Actually looking at that sheet than looking at the letter its pretty clear at a single glance he has outlined those notes to which correspond to his anots and than later wrote her a song using the anots as a shortened version of the full music sheet.

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  2. The Dorabella Cipher Solution

    Ciphertext (transcribed):
    AIBJQCUJTDKEWXENEECIIEXSDSVKL
    UEUCUJTHJBEEBCVWUEKECFLWXSTTSKL
    BLCFLBXFMVLBECFWLXJIVLCJXSJ

    Key:
    PSTYEHKWBARIGMXJFVOLDUNCZQ

    Plaintext:
    PBS AFT DALYRENCE MEET B BECO YOUR IDEDTD ALWASE
    E STUNDER E THINC OLL OR IS IT HIS CH GUISE
    THNIC ABU IT ACOA

    Message:
    Problems after dalliance meet is because your identity always
    a stutter I think all or is it his charming guise?
    Think about it acolyte.

    ReplyDelete
  3. It's time to stop using the same methods that don't produce a clear message or offering random decryptions with no explanation as to how they arrive at their cleartext. Please visit https://jamesmulliss.wordpress.com/a-new-approach/ for a solution that doesn't muck around in well worn tracks.

    ReplyDelete