C I P H E R
During the Civil War, both the Union and Confederate armies had specialized divisions whose job was to relay messages within the army. The main method of communication was by telegraph, but since the enemy could easily intercept these, both sides encoded their messages for secrecy.
The Union Signal Corps, led by Albert J. Meyer, and the Confederate Signal Corps, led by Edward Porter Alexander, both used these signal disks to cipher, or encrypt, their messages.
The Union cipher disk, shown to the left, with Albert J. Meyer’s initials, was used by rotating the letters to the different codes. For example, H could be 1888, 88, or any other number as the inner disk was spun, changing the cipher for different messages. The Confederate cipher, below, worked similarly but with only changes of letters instead (currently shifted back 3 letters, A meaning X). These codes were difficult to break, keeping the battle plans safe and secret.
The Union Signal Corps, led by Albert J. Meyer, and the Confederate Signal Corps, led by Edward Porter Alexander, both used these signal disks to cipher, or encrypt, their messages.
The Union cipher disk, shown to the left, with Albert J. Meyer’s initials, was used by rotating the letters to the different codes. For example, H could be 1888, 88, or any other number as the inner disk was spun, changing the cipher for different messages. The Confederate cipher, below, worked similarly but with only changes of letters instead (currently shifted back 3 letters, A meaning X). These codes were difficult to break, keeping the battle plans safe and secret.
"Discovering the Civil War." Press Kit:. National Archives, n.d. Web. 05 Dec. 2013. <http://www.archives.gov/press/press-kits/civil-war/gallery-page13.html>.
"Confederate Cipher Disc." Confederate Cipher Disc. Crypto Museum, 29 Oct. 2012. Web. 06 Dec. 2013. <http://www.cryptomuseum.com/crypto/usa/ccd/img/301058/001/full.jpg>
"Confederate Cipher Disc." Confederate Cipher Disc. Crypto Museum, 29 Oct. 2012. Web. 06 Dec. 2013. <http://www.cryptomuseum.com/crypto/usa/ccd/img/301058/001/full.jpg>