A first course in cryptanalysis..

This is a World War II textbook on cryptanalysis by Jack Martin Wolfe, Department of Mathematics, published (at least in part) by the Brooklyn College Press. There are at least three volumes, including an appendix which contains the following: - Playfair Idiomorphs - Lesson 15: four-quadrant matrix digraphic substitution - Lesson 16: polygraphic substitution: An introduction to L. S. Hill's linear transformation apparatus of cryptography Modern computer-based cryptography (i.e., public/private key, DES, elliptic, etc.) this is not. This is old-fashioned pencil-and-paper cryptography and cryptanalysis, much as in William F. Friedman's works -- which were classified at the time and thus not available to the general public.