Rotor machine
Encyclopedia
Cryptography
Cryptography is the practice and study of techniques for secure communication in the presence of third parties...
, a rotor machine is an electro-mechanical device used for encrypting
Encryption
In cryptography, encryption is the process of transforming information using an algorithm to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information...
and decrypting secret messages. Rotor machines were the cryptographic state-of-the-art for a prominent period of history; they were in widespread use in the 1920s–1970s. The most famous example is the German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
Enigma machine
Enigma machine
An Enigma machine is any of a family of related electro-mechanical rotor cipher machines used for the encryption and decryption of secret messages. Enigma was invented by German engineer Arthur Scherbius at the end of World War I...
, whose messages were deciphered by the Allies during World War II, producing intelligence code-named Ultra
Ultra
Ultra was the designation adopted by British military intelligence in June 1941 for wartime signals intelligence obtained by "breaking" high-level encrypted enemy radio and teleprinter communications at the Government Code and Cypher School at Bletchley Park. "Ultra" eventually became the standard...
.
The primary component is a set of rotors, also termed wheels or drums, which are rotating disks with an array of electrical contacts on either side. The wiring between the contacts implements a fixed substitution of letters, replacing them in some complex fashion. On its own, this would offer little security; however, after encrypting each letter, the rotors advance positions, changing the substitution. By this means, a rotor machine produces a complex polyalphabetic substitution cipher, which changes with every keypress.
Background
Substitution cipher
In cryptography, a substitution cipher is a method of encryption by which units of plaintext are replaced with ciphertext according to a regular system; the "units" may be single letters , pairs of letters, triplets of letters, mixtures of the above, and so forth...
, where letters in a message were systematically replaced using some secret scheme. Monoalphabetic substitution ciphers used only a single replacement scheme — sometimes termed an "alphabet"; this could be easily broken, for example, by using frequency analysis
Frequency analysis
In cryptanalysis, frequency analysis is the study of the frequency of letters or groups of letters in a ciphertext. The method is used as an aid to breaking classical ciphers....
. Somewhat more secure were schemes involving multiple alphabets, polyalphabetic cipher
Polyalphabetic cipher
A polyalphabetic cipher is any cipher based on substitution, using multiple substitution alphabets. The Vigenère cipher is probably the best-known example of a polyalphabetic cipher, though it is a simplified special case...
s. Because such schemes were implemented by hand, only a handful of different alphabets could be used; anything more complex would be impractical. However, using only a few alphabets left the ciphers vulnerable to attack. The invention of rotor machines mechanised polyalphabetic encryption, providing a practical way to use a much larger number of alphabets.
The earliest cryptanalytic technique was frequency analysis
Frequency analysis
In cryptanalysis, frequency analysis is the study of the frequency of letters or groups of letters in a ciphertext. The method is used as an aid to breaking classical ciphers....
, in which letter patterns unique to every language could be used to discover information about the substitution alphabet(s) in use in a mono-alphabetic substitution cipher
Substitution cipher
In cryptography, a substitution cipher is a method of encryption by which units of plaintext are replaced with ciphertext according to a regular system; the "units" may be single letters , pairs of letters, triplets of letters, mixtures of the above, and so forth...
. For instance, in English, the plaintext letters E, T, A, O, I, N and S, are usually easy to identify in ciphertext on the basis that since they are very frequent (see ETAOIN SHRDLU
ETAOIN SHRDLU
ETAOIN SHRDLU is a nonsense phrase that sometimes appeared in print in the days of "hot type" publishing because of a custom of Linotype machine operators. It appeared frequently enough that it became part of the lore of newspapers...
), their corresponding ciphertext letters will also be as frequent. In addition, bigram
Bigram
Bigrams or digrams are groups of two written letters, two syllables, or two words, and are very commonly used as the basis for simple statistical analysis of text. They are used in one of the most successful language models for speech recognition...
combinations like NG, ST and others are also very frequent, while others are rare indeed (Q followed by anything other than U for instance). The simplest frequency analysis relies on one ciphertext
Ciphertext
In cryptography, ciphertext is the result of encryption performed on plaintext using an algorithm, called a cipher. Ciphertext is also known as encrypted or encoded information because it contains a form of the original plaintext that is unreadable by a human or computer without the proper cipher...
letter always being substituted for a plaintext
Plaintext
In cryptography, plaintext is information a sender wishes to transmit to a receiver. Cleartext is often used as a synonym. Before the computer era, plaintext most commonly meant message text in the language of the communicating parties....
letter in the cipher: if this is not the case, deciphering the message is more difficult. For many years, cryptographers attempted to hide the telltale frequencies by using several different substitutions for common letters, but this technique was unable to fully hide patterns in the substitutions for plaintext letters. Such schemes were being widely broken by the 16th century.
In the mid-15th century, a new technique was invented by Alberti
Leone Battista Alberti
Leon Battista Alberti was an Italian author, artist, architect, poet, priest, linguist, philosopher, cryptographer and general Renaissance humanist polymath...
, now known generally as polyalphabetic cipher
Polyalphabetic cipher
A polyalphabetic cipher is any cipher based on substitution, using multiple substitution alphabets. The Vigenère cipher is probably the best-known example of a polyalphabetic cipher, though it is a simplified special case...
s, which recognised the virtue of using more than a single substitution alphabet; he also invented a simple technique for "creating" a multitude of substitution patterns for use in a message. Two parties exchanged a small amount of information (referred to as the key) and used it to create many substitution alphabets, and so many different substitutions for each plaintext letter over the course of a single plaintext. The idea is simple and effective, but proved more difficult to use than might have been expected. Many ciphers were only partial implementations of Alberti's, and so were easier to break than they might have been (e.g. the Vigenère cipher
Vigenère cipher
The Vigenère cipher is a method of encrypting alphabetic text by using a series of different Caesar ciphers based on the letters of a keyword. It is a simple form of polyalphabetic substitution....
).
Not until the 1840s (Babbage) was any technique known which could reliably break any of the polyalphabetic ciphers. His technique also looked for repeating patterns in the ciphertext
Ciphertext
In cryptography, ciphertext is the result of encryption performed on plaintext using an algorithm, called a cipher. Ciphertext is also known as encrypted or encoded information because it contains a form of the original plaintext that is unreadable by a human or computer without the proper cipher...
, which provide clues about the length of the key. Once this is known, the message essentially becomes a series of messages, each as long as the length of the key, to which normal frequency analysis can be applied. Charles Babbage
Charles Babbage
Charles Babbage, FRS was an English mathematician, philosopher, inventor and mechanical engineer who originated the concept of a programmable computer...
, Friedrich Kasiski
Friedrich Kasiski
Major Friedrich Wilhelm Kasiski was a Prussian infantry officer, cryptographer and archeologist. Kasiski was born in Schlochau, West Prussia .-Military service:...
, and William F. Friedman
William F. Friedman
William Frederick Friedman was a US Army cryptographer who ran the research division of the Army's Signals Intelligence Service in the 1930s, and parts of its follow-on services into the 1950s...
are among those who did most to develop these techniques.
Cipher designers tried to get users to use a different substitution for every letter, but this usually meant a very long key, which was a problem in several ways. A long key takes longer to convey (securely) to the parties who need it, and so mistakes are more likely in key distribution. Also, many users do not have the patience to carry out lengthy, letter perfect evolutions, and certainly not under time pressure or battlefield stress. The 'ultimate' cipher of this type would be one in which such a 'long' key could be generated from a simple pattern (ideally automatically), producing a cipher in which there are so many substitution alphabet
Alphabet
An alphabet is a standard set of letters—basic written symbols or graphemes—each of which represents a phoneme in a spoken language, either as it exists now or as it was in the past. There are other systems, such as logographies, in which each character represents a word, morpheme, or semantic...
s that frequency counting and statistical attacks would be effectively impossible. Enigma, and the rotor machines generally, were just what was needed since they were seriously polyalphabetic, using a different substitution alphabet for each letter of plaintext, and automatic, requiring no extraordinary abilities from their users. Their messages were, generally, much harder to break than any previous ciphers.
Mechanization
It is relatively straightforward to create a machine for performing simple substitution. We can consider an electrical system with 26 switches attached to 26 light bulbs; when you turn on any one of the switches, one of the light bulbs is illuminated. If each switch is operated by a key on a typewriterTypewriter
A typewriter is a mechanical or electromechanical device with keys that, when pressed, cause characters to be printed on a medium, usually paper. Typically one character is printed per keypress, and the machine prints the characters by making ink impressions of type elements similar to the pieces...
, and the bulbs are labelled with letters, then such a system can be used for encryption by choosing the wiring between the keys and the bulb: for example, typing the letter A would make the bulb labelled Q light up. However, the wiring is fixed, providing little security.
Rotor machines build on this idea by, in effect, changing the wiring with each key stroke. The wiring is placed inside a rotor, and then rotated with a gear every time a letter was pressed. So while pressing A the first time might generate a Q, the next time it might generate a J. Every letter pressed on the keyboard would spin the rotor and get a new substitution, implementing a polyalphabetic substitution cipher.
Depending on the size of the rotor, this may or may not be more secure than hand ciphers. If the rotor has only 26 positions on it, one for each letter, then all messages will have a (repeating) key 26 letters long. Although the key itself (mostly hidden in the wiring of the rotor) might not be known the methods for attacking these types of codes don't need that information. So while such a single rotor machine is certainly easy to use, it's no more secure than any other partial polyalphabetic cipher system.
But this is easy to correct. Simply stack more rotors next to each other, and gear them together. After the first rotor spins "all the way", make the rotor beside it spin one position. Now you would have to type 26 × 26 = 676 letters (for the Latin alphabet
Latin alphabet
The Latin alphabet, also called the Roman alphabet, is the most recognized alphabet used in the world today. It evolved from a western variety of the Greek alphabet called the Cumaean alphabet, which was adopted and modified by the Etruscans who ruled early Rome...
) before the key repeats, and yet it still only requires you to communicate a key of two letters/numbers to set things up. If a key of 676 length is not long enough, another rotor can be added, resulting in a period 17,576 letters long.
In order to be as easy to decipher as encipher, some rotor machines, most notably the Enigma machine
Enigma machine
An Enigma machine is any of a family of related electro-mechanical rotor cipher machines used for the encryption and decryption of secret messages. Enigma was invented by German engineer Arthur Scherbius at the end of World War I...
, were designed to be symmetrical, i.e., encrypting twice with the same settings recovers the original message (see involution).
Invention
The concept of a rotor machine occurred to a number of inventors independently at a similar time.In 2003, it emerged that the first inventors were two Dutch naval officers
Royal Netherlands Navy
The Koninklijke Marine is the navy of the Netherlands. In the mid-17th century the Dutch Navy was the most powerful navy in the world and it played an active role in the wars of the Dutch Republic and later those of the Batavian Republic and the Kingdom of the Netherlands...
, Theo A. van Hengel (1875 – 1939) and R. P. C. Spengler (1875 – 1955) in 1915 (De Leeuw, 2003). Previously, the invention had been ascribed to four inventors working independently and at much the same time: Edward Hebern
Edward Hebern
Edward Hugh Hebern was an early inventor of rotor machines, devices for encryption.-Background:Edward Hugh Hebern was born in Streator, Illinois on April 23, 1869. His parents were Charles and Rosanna Hebern. They met in Harris County, Texas while Charles was serving as guard and escort from the...
, Arvid Damm, Hugo Koch
Hugo Koch
Hugo Alexander Koch was a Dutch inventor who conceived of and patented an idea for machine encryption — the rotor machine, although he was not the first to do so...
and Arthur Scherbius
Arthur Scherbius
Arthur Scherbius was a German electrical engineer who patented an invention for a mechanical cipher machine, later sold as the Enigma machine.Scherbius was born in Frankfurt am Main and his father was a small businessman...
.
In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
Edward Hugh Hebern built a rotor machine using a single rotor in 1917. He became convinced he would get rich selling such a system to the military, the Hebern Rotor Machine
Hebern rotor machine
The Hebern Rotor Machine was an electro-mechanical encryption machine built by combining the mechanical parts of a standard typewriter with the electrical parts of an electric typewriter, connecting the two through a scrambler...
, and produced a series of different machines with one to five rotors. His success was limited, however, and he went bankrupt in the 1920s. He sold a small number of machines to the US Navy in 1931.
In Hebern's machines the rotors could be opened up and the wiring changed in a few minutes, so a single mass-produced system could be sold to a number of users who would then produce their own rotor keying. Decryption consisted of taking out the rotor(s) and turning them around to reverse the circuitry. Unknown to Hebern, William F. Friedman
William F. Friedman
William Frederick Friedman was a US Army cryptographer who ran the research division of the Army's Signals Intelligence Service in the 1930s, and parts of its follow-on services into the 1950s...
of the US Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
's SIS
Signals Intelligence Service
The Signals Intelligence Service was the United States Army codebreaking division, headquartered at Arlington Hall. It was a part of the Signal Corps so secret that outside the office of the Chief Signal officer, it did not officially exist. William Friedman began the division with three "junior...
promptly demonstrated a flaw in the system that allowed the ciphers from it, and from any machine with similar design features, to be cracked with enough work.
Another early rotor machine inventor was Dutchman Hugo Koch
Hugo Koch
Hugo Alexander Koch was a Dutch inventor who conceived of and patented an idea for machine encryption — the rotor machine, although he was not the first to do so...
, who filed a patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
on a rotor machine in 1919. At about the same time in Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
, Arvid Gerhard Damm
Arvid Gerhard Damm
Arvid Gerhard Damm was a Swedish engineer and inventor. He designed a number of cipher machines, and was one of the early inventors of the wired rotor principle for machine encipherment. His company, AB Cryptograph, was a predecessor of Crypto AG....
invented and patented another rotor design. However, the rotor machine was ultimately made famous by Arthur Scherbius
Arthur Scherbius
Arthur Scherbius was a German electrical engineer who patented an invention for a mechanical cipher machine, later sold as the Enigma machine.Scherbius was born in Frankfurt am Main and his father was a small businessman...
, who filed a rotor machine patent in 1918. Scherbius later went on to design and market the Enigma machine
Enigma machine
An Enigma machine is any of a family of related electro-mechanical rotor cipher machines used for the encryption and decryption of secret messages. Enigma was invented by German engineer Arthur Scherbius at the end of World War I...
.
The Enigma machine
- Main article: Enigma machineEnigma machineAn Enigma machine is any of a family of related electro-mechanical rotor cipher machines used for the encryption and decryption of secret messages. Enigma was invented by German engineer Arthur Scherbius at the end of World War I...
Enigma machine
An Enigma machine is any of a family of related electro-mechanical rotor cipher machines used for the encryption and decryption of secret messages. Enigma was invented by German engineer Arthur Scherbius at the end of World War I...
used during World War II, of which there were a number of variants.
The standard Enigma model, Enigma I, used three rotors. At the end of the stack of rotors was an additional, non-rotating disk, the "reflector," wired such that the input was connected electrically back out to another contact on the same side and thus was "reflected" back through the three-rotor stack to produce the ciphertext
Ciphertext
In cryptography, ciphertext is the result of encryption performed on plaintext using an algorithm, called a cipher. Ciphertext is also known as encrypted or encoded information because it contains a form of the original plaintext that is unreadable by a human or computer without the proper cipher...
.
When current was sent into most other rotor cipher machines, it would travel through the rotors and out the other side to the lamps. In the Enigma, however, it was "reflected" back through the disks before going to the lamps. The advantage of this was that there was nothing that had to be done to the setup in order to decipher a message; the machine was "symmetrical" at all times.
The Enigma's reflector guaranteed that no letter could be enciphered as itself, so an A could never turn back into an A. This helped Polish and, later, British efforts to break the cipher. (See Cryptanalysis of the Enigma
Cryptanalysis of the Enigma
Cryptanalysis of the Enigma enabled the western Allies in World War II to read substantial amounts of secret Morse-coded radio communications of the Axis powers that had been enciphered using Enigma machines. This yielded military intelligence which, along with that from other decrypted Axis radio...
.)
Scherbius joined forces with a mechanical engineer named Ritter and formed Chiffriermaschinen AG in Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
before demonstrating Enigma to the public in Bern in 1923, and then in 1924 at the World Postal Congress in Stockholm
Stockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...
. In 1927 Scherbius bought Koch's patents, and in 1928 they added a plugboard, essentially a non-rotating manually-rewireable fourth rotor, on the front of the machine. After the death of Scherbius in 1929, Willi Korn was in charge of further technical development of Enigma.
As with other early rotor machine efforts, Scherbius had limited commercial success. However, the German armed forces, responding in part to revelations that their codes had been broken during World War I, adopted the Enigma to secure their communications. The German Navy
Kriegsmarine
The Kriegsmarine was the name of the German Navy during the Nazi regime . It superseded the Kaiserliche Marine of World War I and the post-war Reichsmarine. The Kriegsmarine was one of three official branches of the Wehrmacht, the unified armed forces of Nazi Germany.The Kriegsmarine grew rapidly...
adopted Enigma in 1926, and the German Army
Reichswehr
The Reichswehr formed the military organisation of Germany from 1919 until 1935, when it was renamed the Wehrmacht ....
began to use a different variant around 1928.
The Enigma (in several variants) was the rotor machine that Scherbius' company and its successor, Heimsoth & Reinke, supplied to the German military and to such agencies as the Nazi party security organization, the SD
Sicherheitsdienst
Sicherheitsdienst , full title Sicherheitsdienst des Reichsführers-SS, or SD, was the intelligence agency of the SS and the Nazi Party in Nazi Germany. The organization was the first Nazi Party intelligence organization to be established and was often considered a "sister organization" with the...
.
The Poles
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
broke the German Army Enigma beginning in December 1932, not long after it had been put into service. On July 25, 1939, just five weeks before Hitler's invasion of Poland, the Polish General Staff's Cipher Bureau shared its Enigma-decryption methods and equipment with the French and British as the Poles' contribution to the common defense against Nazi Germany.
A few months later, using the Polish techniques, the British began reading Enigma ciphers in collaboration with Polish Cipher Bureau cryptologists who had escaped Poland, overrun by the Germans, to reach Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
. The Poles continued breaking German Army Enigma — along with Luftwaffe
Luftwaffe
Luftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....
Enigma traffic — until work at Station PC Bruno
PC Bruno
PC Bruno was a Polish-French intelligence station that operated outside Paris during World War II, from October 1939 until June 9, 1940. It decrypted German ciphers, most notably messages enciphered on the Enigma machine.-History:...
in France was shut down by the German invasion of May–June 1940.
The British continued breaking Enigma and, assisted eventually by the United States, extended the work to German Naval Enigma traffic (which the Poles had been reading before the war), most especially to and from U-boat
U-boat
U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...
s during the Battle of the Atlantic
Second Battle of the Atlantic
The Battle of the Atlantic was the longest continuous military campaign in World War II, running from 1939 to the defeat of Germany in 1945. At its core was the Allied naval blockade of Germany, announced the day after the declaration of war, and Germany's subsequent counter-blockade. It was at its...
.
Various machines
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
(WWII), both the Germans and Allies developed additional rotor machines. The Germans used the Lorenz SZ 40/42 and Siemens and Halske T52
Siemens and Halske T52
The Siemens and Halske T52, also known as the Geheimfernschreiber , or Schlüsselfernschreibmaschine , was a World War II German teleprinter cipher machine...
machines to encipher teleprinter traffic which used the Baudot code
Baudot code
The Baudot code, invented by Émile Baudot, is a character set predating EBCDIC and ASCII. It was the predecessor to the International Telegraph Alphabet No 2 , the teleprinter code in use until the advent of ASCII. Each character in the alphabet is represented by a series of bits, sent over a...
. The Allies developed the Typex
Typex
In the history of cryptography, Typex machines were British cipher machines used from 1937. It was an adaptation of the commercial German Enigma with a number of enhancements that greatly increased its security....
(British) and the SIGABA
SIGABA
In the history of cryptography, the ECM Mark II was a cipher machine used by the United States for message encryption from World War II until the 1950s...
(American). During the War the Swiss
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
began development on an Enigma improvement which became the NEMA machine which was put into service after WWII. There was even a Japanese developed variant of the Enigma in which the rotors sat horizontally; it was apparently never put into service. The Japanese PURPLE
PURPLE
In the history of cryptography, 97-shiki ōbun inji-ki or Angōki Taipu-B , codenamed Purple by the United States, was a diplomatic cryptographic machine used by the Japanese Foreign Office just before and during World War II...
machine was not a rotor machine, being built around electrical stepping switch
Stepping switch
In electrical controls, a stepping switch, also known as a stepping relay, is an electromechanical device which allows an input connection to be connected to one of a number of possible output connections, under the control of a series of electrical pulses. It can step on one axis , or on two axes...
es, but was conceptually similar.
Rotor machines continued to be used even in the computer age. The KL-7
KL-7
The TSEC/KL-7, code named ADONIS and POLLUX, was an off-line non-reciprocal rotor encryption machine. The KL-7 had eight rotors to encrypt the text, seven of which moved in a complex pattern, controlled by notched rings. The non-moving rotor was in fourth from the left of the stack. The encrypted...
(ADONIS), an encryption machine with 8 rotors, was widely used by the U.S. and its allies from the 1950s until the 1980s. The last Canadian
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
message encrypted with a KL-7 was sent on June 30, 1983. The Soviet Union and its allies used a 10-rotor machine called Fialka
Fialka
In cryptography, Fialka is the name of a Cold War-era Soviet cipher machine. A rotor machine, the device uses 10 rotors, each with 30 contacts along with mechanical pins to control stepping. It also makes use of a punched card mechanism. "Fialka" means "violet" in Russian...
well into the 1970s.
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
-based Tatjana van Vark http://www.tatjavanvark.nl/index.html. This unusual device is inspired by Enigma, but makes use of 40-point rotors, allowing letters, numbers and some punctuation; each rotor contains 509 parts http://www.tatjavanvark.nl/tvv1/pht10.html.
A software implementation of a rotor machine was used in the crypt
Crypt (Unix)
In Unix computing, crypt is the name of both a utility program and a C programming function. Though both are used for encrypting data, they are otherwise essentially unrelated...
command that was part of early UNIX
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
operating systems. It was among the first software programs to run afoul of U.S. export regulations which classified cryptographic implementations as munitions.
List of rotor machines
- Combined Cipher MachineCombined Cipher MachineThe Combined Cipher Machine was a common cipher machine system for securing Allied communications during World War II and for a few years after amongst NATO...
- Enigma machineEnigma machineAn Enigma machine is any of a family of related electro-mechanical rotor cipher machines used for the encryption and decryption of secret messages. Enigma was invented by German engineer Arthur Scherbius at the end of World War I...
- Lorenz SZ 40/42
- Siemens and Halske T52Siemens and Halske T52The Siemens and Halske T52, also known as the Geheimfernschreiber , or Schlüsselfernschreibmaschine , was a World War II German teleprinter cipher machine...
- FialkaFialkaIn cryptography, Fialka is the name of a Cold War-era Soviet cipher machine. A rotor machine, the device uses 10 rotors, each with 30 contacts along with mechanical pins to control stepping. It also makes use of a punched card mechanism. "Fialka" means "violet" in Russian...
- Hebern rotor machineHebern rotor machineThe Hebern Rotor Machine was an electro-mechanical encryption machine built by combining the mechanical parts of a standard typewriter with the electrical parts of an electric typewriter, connecting the two through a scrambler...
- HX-63HX-63The HX-63 was an advanced rotor machine designed by Crypto AG, who started the design in 1952. The machine had nine rotors, each with 41 contacts. There were 26 keyboard inputs and outputs, leaving 15 wires to "loop back" through the rotors via a different path. Moreover, each rotor wire could be...
- KL-7KL-7The TSEC/KL-7, code named ADONIS and POLLUX, was an off-line non-reciprocal rotor encryption machine. The KL-7 had eight rotors to encrypt the text, seven of which moved in a complex pattern, controlled by notched rings. The non-moving rotor was in fourth from the left of the stack. The encrypted...
- LacidaLacidaThe Lacida was a Polish rotor cipher machine. It was designed and produced before World War II by Poland's Cipher Bureau for prospective wartime use by Polish military higher commands.-History:...
- M-325M-325In the history of cryptography, M-325, also known as SIGFOY, was an American rotor machine designed by William F. Friedman in 1936. Between 1944 and 1946, more than 1,100 machines were deployed within the United States Foreign Service. Its use was discontinued in 1946 because of faults in operation...
- MercuryMercury (cipher machine)Mercury was a British cipher machine used by the Air Ministry from 1950 until at least the early 1960s. Mercury was an online rotor machine descended from Typex, but modified to achieve a longer cycle length using a so-called double-drum basket system....
- NEMANEMA (machine)In the history of cryptography, the NEMA , also designated the T-D , was a 10-wheel rotor machine designed by the Swiss Army during World War II as a replacement for their Enigma machines.-History:The Swiss became aware that their current machine, a commercial Enigma , had been broken by...
- OMI cryptographOMI cryptographThe OMI cryptograph was a rotor cipher machine produced and sold by Italian firm Ottico Meccanica Italiana in Rome.The machine had seven rotors, including a reflecting rotor. The rotors stepped regularly...
- PortexPortexPortex was a British cipher machine. A rotor machine, the device used eight rotors each with a tyre ring and an insert. The machine was used mainly by the secret services from the late 1940s to the early 1950s.-References:...
- REDRed (cipher machine)In the history of cryptography, 91-shiki injiki or Angōki Taipu-A , codenamed Red by the United States, was a diplomatic cryptographic machine used by the Japanese Foreign Office before and during World War II. A relatively simple device, it was quickly broken by western cryptographers...
- SIGABASIGABAIn the history of cryptography, the ECM Mark II was a cipher machine used by the United States for message encryption from World War II until the 1950s...
- SIGCUMSIGCUMSIGCUM, also known as Converter M-228, was a rotor cipher machine used to encrypt teleprinter traffic by the United States Army. Hastily designed by William Friedman and Frank Rowlett, the system was put into service in January 1943 before any rigorous analysis of its security had taken place...
- Hagelin'sBoris HagelinBoris Caesar Wilhelm Hagelin was a Swedish businessman and inventor of encryption machines.Born of Swedish parents in the Caucasus , Hagelin attended Lundsberg boarding school and later studied mechanical engineering at the Royal Institute of Technology in Stockholm, graduating in 1914...
family of machines including the C-36C-36 (cipher machine)The C-35 and C-36 were cipher machines designed by Swedish cryptographer Boris Hagelin in the 1930s. These were the first of Hagelin's cipher machines to feature the pin-and-lug mechanism...
, the C-52C-52 (cipher machine)The C-52 and CX-52 were cipher machines manufactured by Crypto AG starting 1951/1952. These pin-and-lug type cipher machines were advanced successors of the C-38/M-209. The machine measures 8 1/2in × 5 3/8in × 4 3/8in...
the CD-57CD-57The CD-57 was a portable, mechanical cipher machine manufactured by Crypto AG, first produced in 1957.The CD-57 was a portable, mechanical cipher machine manufactured by Crypto AG, first produced in 1957....
and the M-209M-209In cryptography, the M-209, designated CSP-1500 by the Navy is a portable, mechanical cipher machine used by the US military primarily in World War II, though it remained in active use through the Korean War... - BID/60BID/60BID/60 was a British encryption machine. It was used by the British intelligence services from around 1949 or 1950 onwards. The system is a rotor machine, and would appear to have used 10 rotors...
(Singlet) - TypexTypexIn the history of cryptography, Typex machines were British cipher machines used from 1937. It was an adaptation of the commercial German Enigma with a number of enhancements that greatly increased its security....