Cipher Machines



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Cipher Machines Through History

This website tells the story of the ingenuity and advancement of cipher technology throughout history. Maybe even more ingenious is the development of code-breaking technology and espionage in order to counter those advances. The winners in this intellectual arms race enjoyed a huge advantage on the battlefield or in the spy vs. spy world of a cold war, which led to a direct impact on the course of history.

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 ciphers were secure throughout WW2 but both were broken by the Allies, which made a significant difference during WW2. Breaking the Nazi Enigma code also spurred the development of modern computing.

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 called the CX-52, which was more secure than the previous Hagelin design used by the US military. This new cipher device was used by the diplomats, military and commercial companies of 120 different countries. In addition to the technological advances of this new cipher machine, another reason for its success was due to the perception of neutrality offered by having Crypto AG based in Switzerland. Hagelin betrayed this trust and made a secret deal with the US NSA in the late 1950s, allowing the US government unfettered access to the world's secrets for many decades.

US government agents working as spies for Russia and Israel disclosed this secret, which became public in 1992. This resulted in most countries abandoning their Hagelin cipher machines and the near collapse of Crypto AG. Marc Rich, an Israeli billionaire investor and fugitive from US justice, made a "sweetheart deal" with Crypto AG and the controversy and suspicion surrounding this company continues.

The story of the "Clipper chip" is a little-known intrigue of the most far-reaching proportions. In 1993, the US government attempted to require all US manufacturers to install this chip with a proprietary cipher algorithm designed by the NSA in all communications devices; phones, PCs, routers, switches, etc. This would give the US government a public "back door" access into all communications and outlaw the use of all other public key encryption systems.

This egregious intrusion into the personal privacy of every US citizen was thwarted at the last minute by two major developments. Matt Blaze of AT&T, the only company to have a product using this chip, found a vulnerability in the Clipper chip. Before the NSA could correct this design flaw, a new encryption program was offered as open-source code and was quickly adopted by many companies around the world. This software was modestly (or maybe ironically) called PGP for Pretty Good Privacy, which is still in use today.

This brazen attempt by the US government to trample the privacy rights of its citizens has never been widely reported, but luckily the codebreakers won this battle. After the terrorist attack of September 11, 2001, the US Congress hastily passed the "Patriot Act" which allows the US government complete access to all US communications, without any judicial oversight. This law was recently extended to 2014, so the battle by the US government against the 4th amendment rights of its citizens continues.

As far as we know, the current public key cipher systems are secure. They are all based on the one-way mathematical function of finding the prime factors of large numbers. Multiplying two large prime numbers is easy, finding the factors of the resulting number is not as easy. Currently, there is no known algorithm to find the prime factors of a large number and a brute force attack is also not feasible with current computer speeds. So the coders now have the advantage unless a mathematical way of finding prime factors is discovered or until massively parallel computing is developed, such as with DNA computing. Who knows, we may find out 30 years from now that the US or some other government had this technology all along. This is not paranoia, just a reasoned study of history, which has shown the pendulum will eventually swing to the side of the codebreakers.

Most of the information on this website will be an overview of the technology and history of a variety of specific cipher machines, encompassing the major types of ciphers used throughout history. The very detailed and high resolution pictures, including the internals of these devices, are from my personal collection of cipher and communications equipment. Included are the Nazi Enigma machine, US M-94 cipher wheel, US M-209 ciphers, CX-52 & CD-57 Hagelin cipher machines, NEMA cipher, Transvertex cipher, aircraft IFF cipher, Navajo code talker radio, rare Japanese field radios, burst encoders, voice scramblers, the Clipper chip and other modern ciphers.

Cipher Machines

Caesar Cipher
Julius Caesar
One of the earliest recorded examples of using ciphers was employed by Julius Caesar in communicating with his generals. This cipher was also the simplest, a shift of the alphabet by 3 characters, so "a" was enciphered to "d", "b" was enciphered to "e", etc. This shift of characters remained constant throughout the message and is therefore classed as a monoalphabetic cipher. The solution for this type of cipher, even if the alphabet is mixed randomly, is considered trivial today but served its purpose in the time of Julius Caesar and for many hundreds of years thereafter.

Vigenère Cipher
Vignère Cipher
The Vigenère cipher was named for Blaise de Vigenère, even though it was invented by Leon Battista Alberti in 1467, 56 years before Vigenère was born. It uses a Caesar cipher, but with a different Caesar shift for 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 which can be exploited to decode the message using letter frequency analysis. In fact, the Union regularly decoded the Confederate messages throughout the Civil War. Pictured is a Confederate cipher disk, only five of which are known to exist.

Code Books
Code Book
Codes have been used for centuries and were the preferred method of secret communications well into the 20th century. The difference between a cipher and a code is a cipher typically changes a message on a character by character basis while a code subsitutes a few characters or numbers for whole words or sentences. Often, the code is a 4 or 5 digit number and the sender and receiver must have a code book with thousands or up to many tens of thousands of codes. In the age of telegraph messages, codes were also used to reduce the length of messages, with significant savings from telegraph fees.

Jefferson Wheel Cypher & US M-94 Cipher
Jefferson Wheel Cypher
In the 1790s, Thomas Jefferson invented the "wheel cypher" as he called it, which was a stack of 36 wooden wheels mounted on an axle. Each wheel was unique, with a different random alphabetic arrangement on its circumference. For a small number of short messages, this is considered a very strong cipher, even today. This picture shows a cipher wheel found in a home near Jefferson's mansion in Virginia, which looks exactly like the description given by Jefferson. It now resides in the NSA National Cryptologic Museum in Fort Meade, Maryland. Jefferson's invention was lost to history, until discovered in his papers in 1922. Coincidentally, it was independently re-invented and entered service in the US military in that same year and remained in active use until 1943.

One-Time Pad Cipher
One-Time Pad Cipher
The one-time pad is the only theoretically unbreakable cipher, deriving its name from the use of pads of paper with random numbers or letters written on them which are added to the plaintext message to create the ciphertext. The one-time pad is required to be random, have as many characters as the plaintext message and must be used only once (hence the shorthand description, "endless and senseless"). This was a popular cipher system used by spies in both world wars. See examples of the one-time pad using manual paper pads as well as automated teletype and cipher machines.

Nazi Enigma Machine
The Nazi Enigma machine is undoubtedly the most famous cipher machine in history. This machine, first offered commercially in 1923, looked like a typewriter keyboard with a light panel to display rather than print the output. It used three interchangeable rotors to encipher each letter of a message multiple times with a different cipher alphabet. The Polish and later British and then US cryptographers successfully broke the code, which had a significant effect on the outcome of WW2. 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. An estimated 100,000 Enigma machines were made but now only about 200 are known to exist, of which 80 are in private hands. This is a collector's item for the über-geek, with one selling at auction in Sept. 2011 for $208,000. See close-up pictures of the internals of one of those 80 machines here.

Japanese Purple Cipher
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 public Congressional hearings into who in the US government had warnings about the upcoming attack that the Japanese finally discovered their Purple cipher was broken throughout the war.

Navajo Code Talkers
Navajo TBY Radio
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" or "hummingbird" to mean "fighter plane". They were able to cipher, send and decipher a 3 line message in 20 seconds, the less-secure M-209 required 30 minutes. 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 encipher each character of a message. The US military purchased 140,000 of these devices, named the M-209, 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. By 1943 the M-94 wheel cipher was phased out and replaced by the M-209. Despite being less secure, this cipher did have some advantages over the Enigma on the battlefield. It was light, small, did not need battery power and provided a paper strip printout so it could be operated more quickly and by one person.

Aircraft IFF Code Wheels
IFF Radio
During WW2, advances in radar and faster airplanes meant pilots could no longer depend on sight to identify enemy aircraft in time to engage in battle. The result was many incidents of "friendly fire". In 1940 the IFF radio was invented, which stands for "Identification, Friend or Foe". This automated challenge and response system also required an encryption mechanism so the enemy would not be able to spoof a valid response or use an IFF radio from a downed enemy plane. The IFF radio was the precursor to the transponder, which is in all commercial and military aircraft today.

Swiss NEMA Cipher
Swiss NEMA Cipher
The Swiss NEMA (NEue MAschine) is a 10 wheel cipher machine used by the Swiss Army and Diplomatic Corp, replacing the "Swiss K" version of the commercial Enigma machine, which was the "old machine". The NEMA was first deployed in 1947 and shared many features with the commercial Enigma, including the lack of a plugboard, but used 5 rotors for enciphering the alphabet and 5 paired rotors to give irregular stepping of the rotors. This corrected a major vulnerability of the odometer style stepping of the Enigma machine. Only 640 of these devices were made, which were discontinued in 1975 after the British success in deciphering the Enigma during WW2 was made public.

Swedish Transvertex Cipher
Transvertex HC-9
The Swedish company AB Transvertex developed an all-mechanical, rotor based cipher machine in the early 1950s. The commercial version of this cipher is called the HC-9 and the military version is the KRYAPP 301. This cipher machine uses 5 rotors and a punched card to select one of 16 enciphered alphabets from a second card. The inventor of the HC-9 previously worked for Hagelin's Swedish cipher company, so the HC-9 shares some heritage from the mechanical Hagelin ciphers. The use of the two cards in the machine was designed to make it much faster and simpler to set up and operate compared to the Hagelin cipher machines. The HC-9 remained in service for the Swedish Army until the late 1970s.

Hagelin CX-52 and CD-57 Ciphers
Hagelin CX-52
In 1952 Hagelin designed an improved version of his M-209 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 hand-held version was called the CD-57, which was compatible with its larger brother but small enough for spies and other portable requirements. Basing his company in Switzerland gave an aura of neutrality and precision Swiss engineering, allowing his company to have the confidence of all the countries in the world. It turns out this confidence was betrayed by Hagelin. A secret deal was made with the US NSA, allowing the US unfettered access to all the world's secrets for many decades.

Burst Encoders
Burst Encoders
Burst encoders were important tools for the spies or commandos working behind enemy lines. The RT3 is a post-WW2 West German cipher and burst encoder, developed by the BND (West German CIA). It mechanically stores 25 numbers at a time, requiring the messages to be in code. By attaching the burst encoder to a small, hand-held radio and manually cranking the drum, a coded message is enciphered and sent as morse code at a fraction of a second. It is capable of sending 750 wpm, earning the descriptor of "burst". Not only is the message in code, it is sent in such a short burst the enemy has a hard time picking up the correct signal or finding the spy by direction finding. Also see the Russian magnetic tape burst encoder, the US GRA-71 and the UK Racal MA-4450 burst encoders.

NASA Mercury Coder
NASA Mercury Coder
The NASA Mercury Project was the first human spaceflight program, highlighted by John Glenn's historic flight in 1962. Radio telemetry communication was extremely sensitive and kept secure with a radio tube-based audio encryption device built by Collins Radio Company, the KY-171 Audio Frequency Coder. The decoder was the KY-172 and both were part of the AN/FRW-2 Radio Set, used previously for the secure communication of telemetry data and commands to missiles and drones prior to being used in the Mercury Project.

Voice Scramblers
Voice Scramblers
Early voice scramblers used various methods to alter the analog voice patterns being sent across the radio or wire lines. Some examples of this type of voice scrambler are the KY-57, KY-28 and the MSC-2001 voice encryption units. One strategy was to invert the voice frequency over time splices, another was to mix in a separate sound track which would then be subtracted to decipher the original voice message. Voice scramblers were notoriously unsecure and they later were replaced by digital voice encrption, which could encipher both data and voice.

Clipper Chip
Clipper Chip
The Clipper chip used a cipher algorithm hard-wired on a silicon chip which was developed in 1993 by the US NSA. This chip has a back door which was designed to be used only with a Federal Wiretap authorization. The Clipper chip was required by Presidential decree for all US manufactured communication devices, including phones, PCs, routers, switches, faxes, etc. The only device produced with this chip was the AT&T secure phone which was sold to the US government, until a vulnerability was discovered which immediately obsoleted the chip. The availability of open-source PGP security software doomed the Clipper chip before it could get re-started.

Modern Ciphers
Cisco Router
[Coming Soon] Modern ciphers use the power of computing for very secure and user-friendly cryptography. In fact, the enciphering and deciphering is accomplished without the user even aware it is occurring. In addition to the message privacy the previous cipher machines attempted to provide, modern cryptography adds two additional features, it now authenticates (the sender is who he says he is) and provides data integrity (the message has not been altered). Highlighting this new public key encryption will be the world's first routers, switches,
PIX firewalls, intrusion detection devices, etc., including the history and pictures of each device.

Spy Cameras
Spy Cameras
Spy cameras were essential accessories for the battle of wits game of the spy world. Spy cameras span a gamut of mostly small, concealable cameras used to take pictures of people, scenes and documents. Some cameras were designed to be hidden, such as inside a briefcase, behind a button on a coat or as a pocket watch. Other cameras only needed to be inconspicuous when carried. by Ralph Simpson is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License
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