When the United States declared war on Germany in April 1917, it was woefully unprepared to wage a modern war. Whereas their European counterparts already had t

Can flashing lights send out a secret message? Did a famous spy use sketches of butterflies to hide messages? Can a digital photo hide a secret code? For centur

"In 1953, a man was found dead from cyanide poisoning near the Philadelphia airport with a picture of a Nazi aircraft in his wallet. Taped to his abdomen was an

Explains in simple terms how to encode and decode messages in various ciphers, describes coding machines, and gives formulas for invisible ink.

Secret Codes and Ciphers.