By Gordon Rugg and Gavin Taylor
So why should anyone care about a short cipher that was published in a 1939 textbook? There’s a good reason, and it’s very different from the reasons for caring about the Voynich Manuscript.
With the Voynich Manuscript, there was a tantalising possibility that it might just be the key to a new approach to code making. With the D’Agapeyeff Cipher, the issue is about code breaking.
If you’re a codebreaker, then one of the things you hope for is large quantities of coded material, which give you a better chance of finding those few key points where the code is weak, so you have a chance to break in. Unfortunately for codebreakers, that doesn’t always happen. Often, you’re having to deal with a small quantity of text, but that text is important – maybe a warning of an imminent attack – so codebreakers are very keen to have better ways of getting into short coded texts.
The D’Agapeyeff Cipher is a classic test case for new ways of tackling this problem. It’s short; it was almost certainly written using one of the codes described in the book where it appears; it’s still uncracked, over seventy years later. Gordon had already had one attempt at cracking it, with his student Stephen Antrobus, using a method suggested by our colleague Dr Robert Matthews. It was a high-tech software approach that hadn’t been widely used for this type of problem before. It was well worth a try, and Stephen did an excellent job of building the software, but it didn’t crack the code. We’ll return to that story in a later episode.
So, this time round, we tried a different approach. We still started in the same place, though. Gavin bought a second-hand copy of the first edition of D’Agapeyeff’s book Codes and Ciphers.
Book collectors like first editions because the first edition of a major book can be worth a lot of money, as well as being a rare object that gives its owner more status among other book collectors.
The first edition of Codes and Ciphers isn’t like that. It’s a respectable, very ordinary hardback book from the 1930s. The reason Gavin bought a first edition was that the first edition contains the D’Agapeyeff Cipher. It’s the only edition that does.