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 centuries, spies have used many different ways to pass secret information. Codes and ciphers keep information safe from the enemy. Author Susan K. Mitchell uncovers the secrets to the amazing world of spy codes and ciphers.

Spy Codes and Ciphers 2011, Enslow Publishers

ISBN-13: 9780766037090

Hardcover

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Spy Codes and Ciphers 2011, Enslow Publishers

ISBN-13: 9781598453539

Trade paperback

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