Encryption is the process of converting text into code. Encryption devices are the machines that perform the actual encrypting. Such machines have existed throughout history. Though encryption began more as a need in war than commerce, in the late twentieth century, the latter has taken precedent, especially as more and more business is conducted electronically and digitally.

One of the first encryption devices, the skytale, was devised by the Spartans in the fifth century b.c.. The skytale was a wooden staff, and text was written length-wise on papyrus or the like wrapped tightly around the staff. When the papyrus was unwrapped and delivered, it looked nonsensical until rewrapped around a skytale of the similar thickness. By the late nineteenth century, Thomas Jefferson invented a cipher wheel, a simple encryption device which featured two disks. The alphabet was on one, and the other featured its scrambled...