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December 5, 2012

Roger Williams' Cipher Cracked

Another historical cipher, this one from the 1600s, has been cracked:

Senior math major Lucas Mason-Brown, who has done the majority of the decoding, said his first instinct was to develop a statistical tool. The 21-year-old from Belmont, Mass., used frequency analysis, which looks at the frequency of letters or groups of letters in a text, but initially didn't get far.

He picked up critical clues after learning Williams had been trained in shorthand as a court stenographer in London, and built his own proprietary shorthand off an existing system. Mason-Brown refined his analysis and came up with a rough key.

Williams' system consisted of 28 symbols that stand for a combination of English letters or sounds. How they're arranged is key to their meaning; arrange them one way and you get one word, arrange them another, you get something different. One major complication, according to Mason-Brown: Williams often improvised.

Tags: encryption, history of cryptography

Posted on December 5, 2012 at 6:01 AM • 15 Comments

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