Object Details Author Churchhouse, R. F Contents 1. Introduction -- 2. From Julius Caesar to simple substitution -- 3. Polyalphabetic systems -- 4. Jigsaw ciphers -- 5. Two-letter ciphers -- 6. Codes ...

"This book is a continuation of The history of codes and ciphers in the United States prior to World War I ... and is essentially volume 2 of Historical background of the Signal Security Agency, ...

From bizarre ancient markings to random numbers and letters, codes and ciphers have been used for millennia to send secret messages, hide identities and operate outside the law. Unravelling these ...