Overview of Civil War Codes and Ciphers

Codes, Ciphers and Secret Writing – tenyps

The Secret History of the Civil War: The Thomas T. Eckert Archive of Civil War Codes and Ciphers (SOLD)

Civil War Ciphers Teaching Resources

History of Codes and Ciphers in the United States Prior to World War One (Cryptographic Series): United States Army Security Agency Historical Section, Barker, Wayne G.: 9780894120268: : Books

The Pacific War Online Encyclopedia: Codes

ciphers Decoding the Civil War

Codes, Ciphers and Other Cryptic and Clandestine Communication : Making & Breaking Secret Messages from Hieroglyphs to the Internet (Hardcover)

Decoding a Civil War Cipher - Country Roads Magazine

Code Breaker – The Rosenbach

Union Army Cipher Disk- American Civil War flag telegraphy