The Kryptos sculpture at CIA Headquarters has 4 sections of code on it. The first three have been solved. In 1999 there was a big media splash as Jim Gillogly announced his solution, which had been obtained via a computer attack. Part 4 (the last 97 characters) is as yet unsolved.

I wish I could say that I'd solved Part 4, but I haven't (yet). What I *did* do this week though, was come up with a new solution technique for part 3 which I believe to be the "pencil and paper" method that the original authors of the sculpture intended to be used. It's a way of eyeballing the code, such that anyone with access to the ciphertext ( http://www.washingtonpost.com/wp-srv/national/daily/july99/kryptoscode19.htm ) could quickly make a grid and check the letters off to get the entire message. -- no elaborate mathematical formulae or number-crunchers required.

I've written to Gillogly and a couple other cryptographers to check my work. If anyone else would like to take a look in the meantime, I've got a page describing the technique which is posted at my Kryptos site:

Elonka's Solution to Part 3 of Kryptos