Cryptography and Cryptanalysis Articles, Volume 1

A collection of previously classified cryptology articles from the Army's Signal Corps Bulletin. William F. Friedman gathered and edited them; Aegean Park Press reprinted the set as Volume 1 of two, meant as collateral reading for students of cryptography and cryptanalysis.

This volume contains four articles: Friedman's own "Cryptanalysis," Marcel Givierge's "Problems of Code," Alf Monge's "Solution of the Playfair Cipher," and Howell C. Brown's "Analysis Versus the Probable Word." It closes with an appendix of Playfair cipher problems added for the student. It appeared in 1976 as No. 5 in Aegean Park Press's Cryptographic Series; a companion Volume 2 followed as No. 6.

Friedman edited and largely wrote the material collected here during his years directing Army cryptologic training between the world wars. He had come to cryptology as a geneticist at George Fabyan's Riverbank Laboratories, where he and his wife Elizebeth Smith Friedman did wartime code-breaking work. He then joined the Army's Signal Intelligence Service, which he founded and led starting in 1929. His Signal Corps training texts, including these Bulletin articles, shaped how a generation of American cryptanalysts learned the field before Friedman went on to direct the breaking of the Japanese PURPLE cipher.