Computer scientist and cryptographer.

With Jim Reeds founder of the Voynich Manuscript Mailing List in 1991.

Notable for being the first person to publicly solve parts 1-3 on the CIA's (Wikipedia page Kryptos sculpture refers) in 1999. Also debunked the Beale Ciphers.

His page on Wikipedia, including a list of his writings, is [1] and on chess Programming Wiki [2]

A list of his publications here [3] and here [4].