In previous posts, we saw how we might establish the length of the key used to encode a periodic cipher, such as Vigenère or Beaufort. I showed two methods, the Index of Coincidences and the Kasiski/Kerckhoff.
This is the cipher we’re trying to solve:
VKMHG QFVMO IJOII OHNSN IZXSS CSZEA WWEXU
LIOZB AGEKQ UHRDH IKHWE OBNSQ RVIES LISYK
BIOVF [...]
Previously I discussed how to attack a repeating key (e.g. Vigenère or Beaufort) using a method called ‘Index of Coincidences’
I’d also like to demonstrate the ‘Kasiski/Kerckoff’ attack. This article was brought forward due to a comment on the Index of Coincidences article.
In preparing this article, I used a javascript tool.
Let’s look once again at the [...]
This article discusses the Index of Coincidences, the first step to cracking Vigenère and Beaufort, or any other cipher where a repeating key is applied letter by letter.
The Pigpen Cipher is a simple monoalphabetic substitution which has persisted over the centuries. For example, Freemasons used it in the 18th century to secure their records.
Pigpen is trivial to read if you know the key, and easy to decipher if you don’t.
The Pigpen is so called because the key looks like an aerial view [...]
This refers back to articles upon Lorenz, as well as One Time Pads.
I’ve been playing with a spreadsheet, and have managed to use it to get a basic implementation of a Lorenz-type cipher. It is far from perfect. The key is not generated ‘on the fly’, instead a repeating key is used. This renders the [...]
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