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Cipher Machines Through History

This website tells the story of the ingenuity and advancement of cipher technology throughout history. Equally ingenious is the development of code-breaking technology and espionage in order to counter those advances. The winners in this intellectual arms race enjoy a huge advantage on the battlefield or in the spy vs. spy world of a cold war.

As an example, the German enigma machine was quite an advancement in technology prior to WW2, but the Nazi confidence in its invincibility caused them to ignore some obvious signs of code-breaking. Likewise, the Japanese trusted the integrity of their "Purple Cipher" despite warnings from the Germans the code had been breached by the US. So both the Germans and the Japanese believed their own ciphers were secure throughout WW2 but both were broken by the Allies, which made a significant difference in the outcome of WW2. Breaking the Nazi enigma code also spurred the development of modern computing and the first computers.

The US also used a rotor based cipher machine in WW2, named the M-209 and designed by Boris Hagelin. This cipher was broken by the Germans, but the US was aware of this possibility and only used this machine for tactical messages. Interestingly, the most secure cipher in WW2 was the low-tech "analog" cipher the Navajo Code Talkers used, which was speaking in their native language. The speed and security of this cipher was unmatched by the latest and greatest technological innovations from any country.

The most successful cipher machine after WW2 was sold by Boris Hagelin through his Swiss company, Crypto AG. In 1952, he started selling an improved rotor-based cipher machine to 120 countries which was much more secure than the previous design used by the US military and was called the CX-52. Another reason for his success was due to the perception of neutrality offered by having his company based in Switzerland. In the mid-1970s, an electronic cipher machine was introduced with a "back door" access put in by the US NSA, allowing the US unfettered access to the world's secrets for several decades.

Most of the information on this website will be presented in the form of pictures and presentations to tell the story of this ongoing arms race. Almost all the pictures are from my personal collection of cipher and communications equipment, including a Nazi enigma machine, US M-209 cipher, CX-52 Hagelin cipher machine, Navajo code talker radio and modern ciphers. I have attempted to provide very detailed, close-up photos showing the details of the internals of each of these machines.

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Types of Cipher Machines

Caesar Shift Cipher

One of the earliest recorded examples of using ciphers was employed by Julius Ceasar in communicating with his generals. This cipher was also the simplest, reportedly a shift of the alphabet by 3 characters, so an "a" was enciphered to a "d", a "b" was enciphered to an "e", etc. This shift of characters remained constant throughout the message and is therefore classed as a monoalphabetic cipher. Caesar was also known to have used more complicated ciphers.

Vigenère Cipher

The Vigenère cipher was named for Blaise de Vigenère, even though it was first described by Giovan Battista Bellaso 35 years earlier in 1553. It uses a Caesar cipher with a different shift at each letter in the text, with the amount of the shift defined by a repeating keyword. This is an example of a polyalphabetic cipher and was commonly considered unbreakable even into the 20th century. Keywords shorter than the message (e.g. "Complete Victory" used by the Confederacy during the American Civil War), introduce a cyclic pattern that could be decoded using letter frequency analysis. In fact, the Union regularly decoded the Confederate messages. Pictured is a replica of the Confederate cipher disk, five of which are known to exist.

Jefferson Cipher Wheel

In 1795, Thomas Jefferson invented the "wheel cypher" as he called it, which was a stack of 26 wooden wheels mounted on an axle. Each wheel was unique and had the alphabet arranged randomly around its circumference. The order of each of the wheels on the axle gives the number of possibilities for the key, which is 26! (or 4 X 10**26). For a small number of short messages, this is considered a very strong cipher, even today. The picture shows a replica of Jefferson's invention and is almost identical to the one used by the US military until 1942.

Nazi Enigma Machine

The Nazi Enigma machine is undoubtedly the most famous cipher machine in history. This machine is similar to the Hagelin cipher but uses battery power to light up letters of the message instead of printing and also uses a plugboard. The Polish and later British and then US cryptographers successfully broke the code, shortening WW2 by several years. Despite 11,000 people in Britain and several thousand in the US working on deciphering the Enigma, the secret of the code being broken was not disclosed for almost 30 years, in 1974.

Japanese Purple Cipher

The Japanese Purple Cipher was the diplomatic cipher used by Japan before WW2 and then used by the military throughout the war. This cipher is similar to the Enigma machine and was broken by the US even before the war started. A Japanese diplomat in Germany used this cipher to report back to Japan the Nazi preparations and arms placements to counter the Allies plans for D-Day. The US knowledge that their deception of landing site had worked was a major factor in their confidence to proceed. No intact Purple cipher machines are known to survive the war, pictured is a remnant from the Japanese embassy in Berlin recovered in 1945. The Japanese were told by the Germans that Purple was broken by the US but they refused to believe this until after the war. It was in Congressional hearings about who knew about Pearl Harbor and allowed the Japanese bombings to happen that the Japanese finally discovered their Purple cipher was broken throughout the war.

Navajo Code Talkers

During WW2, the US Marine Corps deployed the American Indian tribe of Navajos to provide "analog" enciphering of military messages. They would talk in their native language and add code words for military terms and armament for which they did not have a translation, for instance they used "iron fish" to mean "submarine". Pictured is the radio used by the Navajo Code Talkers, the ultra-portable TBY radio.

US Army M-209 Cipher

Boris Hagelin developed a mechanical cipher machine that used a series of rotors combined with a "pin and lug" mechanism to allow each character of a message to be enciphered many times. The US military purchased 140,000 of these devices for use during WW2. The US was aware the Germans broke the code, so the use of this machine was limited to tactical battlefield messages. After WW2, Hagelin set up his own company to sell an improved version of this technology with moveable rotors and irregular stepping, which is described below.

Hagelin CX-52 Cipher

In 1952 Hagelin designed an improved version of his cipher machine called the CX-52, which became the most successful cipher machine in history, selling to the military, diplomats and commercial companies in 120 different countries. A later electronic cipher machine was introduced in the 1970s which had a "back door" access inserted by the US NSA, giving the US unfettered access to the world's secrets for several decades.

Modern Ciphers


Modern ciphers use the power of computing to have very secure and user-friendly cryptology. In fact, the enciphering and deciphering is accomplished without the user even aware it is occurring. In addition to the confidentiality the previous cipher machines attempted to provide, modern ciphers add two additional features. They now authenticate (the sender is who he says he is) and provide data integrity (the message has not been altered). An example of this technology is pictured showing a Cisco Systems 2621 router with a Crypto VPN hardware module. Also, you will see the world's first routers, the Cisco AGS+, CGS, IGS, etc.