Computer scientist cracks eighteenth-century secret code

Posted by Emma Woollacott

Three hunded years after it was created, the Copiale Cipher has been broken using machine translation techniques.

An international team of cryptographers has discovered that the mysterious cryptogram reveals the rituals of an 18th-century secret society in Germany whose members were obsessed with eye surgery and ophthalmology.
       
The 75,000-character Copiale Cipher, bound in gold and green brocade paper, is a mixture of letters and symbols, with only two unencrypted phrases: 'Phillipp 1866' and Copiales 3'. It wasn't even known in which language the original document was written.

Computer scientist Kevin Knight of the USC Viterbi School of Engineering first transcribed a machine-readable version of the text, using a computer program he'd created to help quantify the co-occurrences of certain symbols and other patterns.

"When you get a new code and look at it, the possibilities are nearly infinite," Knight said. "Once you come up with a hypothesis based on your intuition as a human, you can turn over a lot of grunt work to the computer."

With the original language unknown, the team acted on a hunch and isolated the Roman and Greek characters distributed throughout the manuscript, then attacked it as a true code.

"It took quite a long time and resulted in complete failure," says Knight.

After trying 80 different languages, the team finally realized the Roman characters were there purely to mislead, and that the abstract symbols held the message.

The team then tested the hypothesis that abstract symbols with similar shapes represented the same letter, or groups of letters - and meaningful German words finally emerged - "Ceremonies of Initiation," followed by "Secret Section."

"This opens up a window for people who study the history of ideas and the history of secret societies," says Knight.

"Historians believe that secret societies have had a role in revolutions, but all that is yet to be worked out, and a big part of the reason is because so many documents are enciphered."

Knight's now turning detective, and is examining the ciphers sent by the Zodiac Killer, a serial murderer who sent taunting messages to the press and who has never been caught.

He also hopes to crack the last section of 'Kryptos' - an encrypted message carved into a sculpture at CIA headquarters - and the Voynich Manuscript, a mysterious medieval document.

There's more information here, including an English translation of the document.