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comparison content/Coding/029-announcing-my-purple-simulator.rst @ 14:6e0d4799796d
Added a blog post about my PURPLE simulator.
Created the simulator tag.
| author | Brian Neal <bgneal@gmail.com> |
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| date | Thu, 20 Feb 2014 19:47:19 -0600 |
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| 13:bcfe2a2c8358 | 14:6e0d4799796d |
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| 1 Announcing my Purple simulator | |
| 2 ############################## | |
| 3 | |
| 4 :date: 2014-02-20 19:59 | |
| 5 :tags: Python, m209, Enigma, Purple, simulator | |
| 6 :slug: announcing-my-purple-simulator | |
| 7 :author: Brian Neal | |
| 8 :Summary: I recently created a simulation of the Japanese PURPLE cipher machine | |
| 9 in Python. | |
| 10 | |
| 11 After working on a `M-209 simulator`_ last summer and an `Enigma simulator`_ the | |
| 12 year before, I got the World War 2 era cipher machine bug again. It all started | |
| 13 by reading about the `Japanese PURPLE machine`_ at Frode Weierud's excellent | |
| 14 CryptoCellar_ website. I read with great interest a paper available at that | |
| 15 site titled *PURPLE Revealed: Simulation and Computer-aided Cryptanalysis of | |
| 16 Angooki Taipu B* by Wes Freeman, Geof Sullivan, and Frode Weierud. This paper | |
| 17 is a fascinating read, with detailed descriptions of how the machine worked, | |
| 18 the complicated keying system employed by the Japanese, and information on | |
| 19 using a technique known as *hill-climbing* to mount a ciphertext only attack on | |
| 20 a messages. Highly recommended! | |
| 21 | |
| 22 After reading the paper I knew I had to try to write a simulator for the PUPRLE | |
| 23 machine in Python_. Writing these simulators is great fun. You have to | |
| 24 understand how the machine works, get a bunch of tiny details correct, have | |
| 25 a bit of patience, and do a lot of detective work and debugging. Once you have | |
| 26 them built, they aren't all that complicated when coded on a modern computer. | |
| 27 But you get an amazing appreciation for these machines as originally | |
| 28 implemented as electro-mechanical devices. The PURPLE machine, for example, | |
| 29 required almost 2,000 wired connections! It is even more amazing when you know | |
| 30 the U.S. code breakers built replicas without even seeing an original Japanese | |
| 31 machine. When the war ended, only a few parts of one Japanese machine were ever | |
| 32 recovered! | |
| 33 | |
| 34 I had a lot of fun writing this and playing with it. I hope someone else finds | |
| 35 it interesting or educational. Please contact me and let me know if you use it | |
| 36 for anything. Please see these links for documentation, the code, and licensing | |
| 37 details: | |
| 38 | |
| 39 * `Purple simulator on PyPI`_ | |
| 40 * `Purple simulator on Bitbucket`_ | |
| 41 | |
| 42 Once again, many thanks to Frode Weierud, Geoff Sullivan, and Wes Sullivan for | |
| 43 the very interesting paper. I'm also grateful to Messrs. Weierud and Sullivan | |
| 44 who provided me with valuable plaintext, advice and encouragement while | |
| 45 I worked on this project. | |
| 46 | |
| 47 I also recommend the book *Battle of Wits: The Complete Story of Codebreaking | |
| 48 in World War II* by Stephen Budiansky, which details the efforts and the people | |
| 49 behind the cracking of the PURPLE cipher. | |
| 50 | |
| 51 .. _M-209 simulator: https://m209.readthedocs.org/en/latest/ | |
| 52 .. _Enigma simulator: http://py-enigma.readthedocs.org/en/latest/ | |
| 53 .. _Japanese PURPLE machine: http://cryptocellar.web.cern.ch/cryptocellar/simula/purple/ | |
| 54 .. _CryptoCellar: http://cryptocellar.web.cern.ch/cryptocellar/ | |
| 55 .. _Python: http://www.python.org/ | |
| 56 .. _Purple simulator on PyPI: https://pypi.python.org/pypi/purple | |
| 57 .. _Purple simulator on Bitbucket: https://bitbucket.org/bgneal/purple/ |