I was reading the Military Cryptanalysis Field Manual at ftp://ftp.ox.ac.uk/pub/crypto/cryptanalysis/ basic_cryptanalysis.ps.tar.gz and was reminded of a book I had partly read a while ago, Doug Hofstadter's _Fluid Concepts & Creative Analogies : Computer Models of the Fundamental Mechanisms of Thought_ (http://www.amazon.com/exec/obidos/ISBN=0465024750/r/0509-6726066-321937). 'Hofstadter and his colleagues created a variety of computer programs that extrapolate sequences, apply pattern-matching strategies, make analogies, and even act "creative." ' For instance, he developes a model that solves a type of newspaper-puzzle cryptogram. The interplay between levels of abstraction ---recognizing words in the plaintext language, and reconstructing the key together from statistical and other constraints (Ch. 4)--- is what's similar between Hofstadter's model and what the field manual describes. Caveats: Hofstadter's book is very dry. The Field Manual only mentions that computers may be useful, and gives advice that may have been useful 70 years ago. ------------------------------------------------------------ David Honig Orbit Technology honig@otc.net Intaanetto Jigyoubu "Windows 95 is a technologically complex product that is best left alone by the government..." ---MSFT Atty B. Smith