19th–20th century Around 1790, Thomas Jefferson theorized a cipher to encode and decode messages to provide a more secure way of military correspondence. The cipher, known today as the Wheel Cipher or the Jefferson Disk, although never actually built, was theorized as a spool that could jumble an English message up to 36 characters. The message could be decrypted by plugging in the jumbled message to a receiver with an identical cipher.
19th–20th century around 1790 thomas jefferson theorized a cipher to encode and decode messages to provide a more secure way of military correspondence the cipher known today as the wheel cipher or the jefferson disk although never actually built was theorized as a spool that could jumble an english message up to 36 characters the message could be decrypted by plugging in the jumbled message to a receiver with an identical cipher