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The National Cipher Challenge

BOSS Technical Notes

In our Library you will find a series of PDFs called the BOSS technical notes. These cover a whole range of topics related to codebreaking and they are free to download. Here is a list, but it is probably worth heading over to the bookcase to browse them for yourself:

  • Technical Note 000 – BOSS Cryptanalyst Handbook. A beginner’s guide to codebreaking
  • Technical Note 001 – Programming for Cryptologists. An introduction to coding (as in, writing software) in Python, designed for the aspiring codebreaker.
  • Technical Note 002 – Two Attacks on Tableau Based Ciphers. A short note on methods for attacking more advanced ciphers like the Vigenere, Beaufort and Gronsfeld. This takes you beyond the standard substitution ciphers.
  • Technical Note 003 – A Book on Classical Cryptography. This is almost an encyclopedia of codebreaking. With examples taken from our previous competitions it introduces a wide range of methods for tackling ciphers ranging from the simplest to some of our more devilish challenges.
  • Technical Note 004 – Breaking Compound Ciphers. One of the best ways to harden a cipher is to combine it with a different one, perhaps combining a substitution with an anagramming cipher to make something much tougher than both. In this note you are introduced to methods that can be used to tackle even them.
  • Technical Note 005 – A mono literal-biliteral-triliteral cipher. This one is a bit of a curiosity, belonging more in the library of a cryptologist than a cryptanalyst. It discusses the construction of a new cipher.
  • Technical Note 006 – Breaking a Porter Cipher with statistics. Frequency analysis is a major tool in the cryptanalyst’s arsenal, and here there is a discussion of how to expand on that technique to break the infamous Porta Cipher
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