Thomas Jefferson, Jefferson's Cipher for the Lewis and Clark Expedition, (developed by Robert Patterson), 1803. Manuscript document, Library of Congress Collection.
Were you aware that Thomas Jefferson had a life long-fascination with gadgets and encryption? While serving as President George Washington's secretary in the 1890s, Jefferson devised the wheel cipher, an ingenious and secure method, using 36 disks, each with the 26 letters of the alphabet arranged around its edge, to encode and decode messages. (A version of this cipher system was even used by the U.S. Army from 1923 – 1942).
The cipher see you here is a different type that Jefferson also used. Shortly after the Louisiana Purchase was made, in May of 1804 American explorers Meriwether Lewis and William Clark set out on a historic expedition intended to help establish diplomacy and trade with Native Americans in the West and find a water route to the Pacific Ocean. Before they left, (now) President Jefferson, who commissioned this extensive mission, presented Lewis with this cipher (developed by a mathematician named Robert Patterson), in order to be able to communicate with him in code at seasonable intervals throughout the expedition. The cipher consists of a 28 column alphanumeric table, in which someone writes the first line to be decoded and then writes out the designated keyword, repeating it for an entire line. Jefferson’s choice of keyword for the cipher was “artichokes.” Yes, “artichokes”!