It’s not really my historical bag, capice?, but some early American ciphers popped their heads over my virtual parapet in the last few days, and I thought I ought to pass them on…
(1) On Christmas Day 1801, Thomas Jefferson received a cipher challenge from “Pennsylvania mathematician Robert Patterson”, that remained unbroken for two centuries. Here’s the cipher itself: according to a comment and example given by “A nonny bunny” on Bruce Schneier’s blog, for “helloworld”, the plaintext would first becomes columnar-transposed to “lrhweollod”, which secondly gets shifted into positions 3 and 2 (the “3” and “2” of the key), and padded with nonsense, before finally being read off in the same c0lumnar-transposed kind of way
1 hw 3 lr 32 ablr 2 eo 1 hw 11 khwl 3 lr 2 eo 20 eoyu 1 ll 1 ll 11 llty 2 od 2 od 20 odtr
I’ve underlined the plaintext (“helloworld”), the key sequence (32,11,20) and the ciphertext (akelobholdlwyttrluyr) to make it a little clearer what’s going on (the original comment lost the formatting). But it’s nice to see a relatively pure transposition cipher out in the wild. 🙂
(2) Here’s a ciphered letter from John Adams to John Jay dating from 1783-1785. There are a fair few web pages on John Jay’s codes and ciphers, as well as on Thomas Jefferson’s own codes and ciphers. John Jay and the agent Silas Deane also used invisible ink-style trickery (according to this CIA page, followed by more on the various ciphers used).