The History and Mathematics of Codes and Code Breaking

Expository Essay - The Dorabella Cipher

Here's Courtney's paper on the Dorabella cipher [PDF].


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  1. Tanner Strickland

    This essay was really interesting. I liked how it included multiple possibilities regarding the true plaintext of the Dorabella cipher, but it also recognized the fact that it is quite likely that no solution to the cipher has been found. Also, I thought that the paper was extremely clear and well-written. It was not nearly as dry as it would have been in a textbook, so it is an appropriate essay for students to read.

    The history and background of the Dorabella cipher were the most clearly explained aspects of this essay, in my opinion. I think the essay does a good job of illustrating events leading up to the creation of the cipher as well as describing the people involved. I found the possibility that the cipher represented a melody to be extremely interesting, too.

    After the discussion of this topic in the paper, I have very few questions that remain unanswered. The only thing that I wondered at the end of the paper was whether there was any amount of notable consensus in the field of cryptography about if the cipher had been cracked, and if so, which plaintext was correct.

    The topic that we have studied in cryptography to which I immediately connected this cipher was the Kryptos cipher. This is because both of these ciphers were created to serve only as a challege to others. They were never a vital means of communication, nor do they reveal the location of anything valuable. Although it is likely that they both contain a message, this message is not important, and the main purpose of these ciphers are to cause others to think creatively to crack them.

  2. Sam Mallick

    This paper does a great job of tying the Dorabella Cipher into other themes from the course. Most fascinating, I believe, is the reference to the Bletchley Park recruitment process. I was left somewhat curious about some of the results these world-renowned cryptographers came up with when they took a crack at the Dorabella.
    It is also interesting that you chose to take a look at a particular cipher that has almost no significance regarding military, politics, or security. This paper reminds us that cryptography can be used as a source of amusement and entertainment by ordinary people. Sometimes in all the seriousness of or class discussions, we forget why people are fascinated with Sherlock Holmes and Edgar Allen Poe.
    One area where I would like to know a little more is Elgar's biographical background. We all know and most have marched to 'Pomp and Circumstance' but what made Elgar interested in cryptology?
    Finally, given the unsolved nature of the cipher, describing the technical aspects of it must have been difficult, but the paper does a good job through use of diagrams and examples of scholarly speculation of explaining what technicalities of the cipher can be understood.

  3. Jonathan O'Hara

    Overall, this essay was a very engaging and interesting read. Courtney did a great job of explaining the cipher itself and it's history. It was interesting how she took a cipher that was not one of extreme significance to national security and safety, but rather a more playful one. Furthermore, she did a good job of not understating the extreme complexity of the cipher. All of her examples of possible solutions to the cipher gave very different, yet very interesting perspectives on how the cipher could possibly be solved.

    The way Courtney delved into the different possibilities of deciphering the Dorabella was, in my opinion, the strongest aspect of her paper. There are not many unsolved ciphers, so learning about all the different attempts and interpretations of the cipher was very interesting and informative. My favorite part of her paper was the connection to music. I cannot think of any other connection between cryptography and music other than Edward Elgar. I also found it interesting how there was multiple interpretations by different cryptographers of the construction of the melody.

    The only 2 weak points of the paper (which were not very weak at all) were some sentence structure errors and the conclusion. Sometimes the sentences were slightly hard to follow and took two or three times to read through in order to understand. This can be fixed quite easily, however, and did not detract much from the paper itself. Also, it seemed that the paper ended a bit abruptly and there was not any sense of a true conclusion.

    Courtney did a great job of including ample information in her paper, which kept me, as the reader, engaged throughout. She was very clear and did not include any extraneous information that did not aid her paper.

  4. Rick Henderson

    I have a high degree of certainty that I have solved Dorabella. Please see:

    Comments and (intelligent) criticisms welcome.

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