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Thursday, December 4, 2014

Cryptanalyst finds familiar text in old cipher

July 2, 2009 — A couple of days ahead of the 233rd birthday of the United States of America, here's an interesting item from today's Wall Street Journal.

As far as scholars can tell, an enciphered letter received by President Thomas Jefferson in 1801 from his friend, Robert Patterson, had gone unsolved for over two centuries — until code-breaker Lawren Smithline took a shot at it in 2007.

Smithline, 36, a mathematician and now a professional cryptanalyst, recently published his solution. It's not quite the "perfect cipher" that the nineteenth-century puzzle's author thought it was: although quite possibly unbreakable in its time, it would have been impractical for everyday use as a quill-and-parchment system. Even though Patterson had a systematic method for sprinkling the ciphertext with numerous nulls, his cryptogram is readily identifiable as a transposition cipher.

Readers will find the content of the letter to be a paraphrased excerpt from a well-known document — one that was written largely by Jefferson himself.


BreakingCodes said...

Immediately after I had posted this item, I found that several other readers had sent me e-mails about the subject during the half-hour or so that I had been researching and writing about it.

Thanks to everyone for your great efforts at helping me get the news out when it happens!

mosherubin said...

David Kahn, in his monumental book "The Codebreakers", states that the underlying crypto-system was known. The solving is still valuable, but certainly doable with today's computers.

For quotes and references in The Codebreakers see a related discussion on "The Crypto Forum".

P.S. Very useful and interesting site -- good luck!

Ken Bauman said...

OK, Robert Patterson's cryptogram is deciphered by Dr. Smithline. What must one do to get the Beale Papers cryptogram C1 looked at? I have published the short plain text: ere fen due red knee ....which can be googled for online viewing. There is an incredible amount of information that is associated with this discovery. Please contact me to discuss this project.

[Editor’s note: A copy of this comment has been moved to a separate post, where a discussion of the topic it presents has been started.]