American Scientist is getting a lot of mileage out of Jefferson lately. In the March-April 2009 issue of American Scientist, mathematician Lawren Smithline helps out the folks at the Papers of Thomas Jefferson by decoding a supposedly-unbreakably-encoded message sent to Jefferson by Philadelphia smarty-pants Robert Patterson in 1801.
Thanks to our sources (hey thanks, Dad!) we have a copy of this article at the library for your reading pleasure. Unfortunately it is not freely available online (unless you are a subscriber to American Scientist); you can purchase the article from them for $12, or locate a library near you that subscribes.