A Cipher to Thomas Jefferson
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On Christmas Day, 1801, Thomas Jefferson received a letter from University of Pennsylvania mathematician Robert Patterson. The last page of that letter employed a cipher described in earlier pages, but Patterson did not include the key. It took more than two centuries for the puzzle to be solved, using a method that has become common in computational biology. The theory behind the cryptanalysis is of the computer age, but the calculating power necessary is of Patterson’s time.