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.

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

Comments

GeekbritDecember 5, 2012 6:40 AM

It isn't a particularly good link even within the US - it took me through to the Buffalo News Association website. Another victory for the Dead Tree media.

stvsDecember 5, 2012 8:50 AM

So what did the cipher text say?

Roger Williams's cipher notes from the margins of An Essay Towards the Reconciling of Differences Among Christians:

There iſt no god but God, Lord Muhammad is the meffenger of God. … They surely difbelieve who say: Lo! God is the third of three; when there is no God save the One God. If they defift not from so saying a painful doom will fall on thofe of them who difbelieve. —Qur'an, Sura 5:72–73

Lowell GilbertDecember 5, 2012 8:57 AM

Note that this wasn't intended as a secret cipher. It was really just a personal shorthand system, and based quite clearly on a well-documented and common shorthand of the time. Although these notes are of some historical interest, they were pretty much in accord with things that he (Roger Williams, the founder of my home state -- Rhode Island) had said more publicly in earlier years. What made it difficult to crack was mostly the abbreviations for specialized theological vocabulary.

stvsDecember 5, 2012 9:00 AM

Seriously, there's an excellent On Point radio show about Roger Williams's influential role on Church and State in America, here.

WinterDecember 6, 2012 5:09 AM

"Note that this wasn't intended as a secret cipher. It was really just a personal shorthand system, and based quite clearly on a well-documented and common shorthand of the time."

There is a maxim in (historical) linguistics:
If the underlying language is known, any script can be deciphered.
In most cases, knowing a related or descended language suffices. However, you may need a lot of text.

FigureitoutDecember 6, 2012 3:08 PM

I've always wondered if a code's really been cracked. With an active MiTM attack you could at least test it w/ Bob in real time; but what if the "plaintext" is just another cipher/OTP? Because wouldn't a brilliant bit of code slip right by looking like normal convos? Kind of maddening to think about...

JonadabDecember 11, 2012 1:05 AM

The article has clearly not been checked for accuracy at all. Among other things, it claims that Williams was the first person to argue in favor of separation of church and state. (He wasn't even born until 1603; Menno Simons, just to pick an arbitrary and rather obvious counterexample, had been dead for more than 40 years by then.)

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