In
cryptographyCryptography is the practice and study of hiding information. Modern cryptography intersects the disciplines of mathematics, computer science, and engineering...
, a
rotor machine is an electro-mechanical device used for
encryptingIn 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 brief but prominent period of history; they were in widespread use in the 1930s–1950s. The most famous example is the
Enigma machineAn Enigma machine is any of a family of related electro-mechanical rotor machines used for the encryption and decryption of secret messages. The first Enigma was invented by German engineer Arthur Scherbius at the end of World War I...
.
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, scrambling 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.
Background
In classical cryptography, one of the earliest encryption methods was the simple
substitution cipherIn 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 analysisIn 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 cipherA 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 analysisIn 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 monoalphabetic
substitution cipherIn 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 SHRDLUETAOIN SHRDLU is the approximate order of frequency of the twelve most commonly used letters in the English language, best known as a nonsense phrase that sometimes appeared in print in the days of "hot type" publishing due to a custom of Linotype machine operators.-Linotype history:The letters on...
), their corresponding ciphertext letters will also be as frequent. In addition,
bigramBigrams 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
ciphertextIn cryptography, ciphertext is the result of 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. This result is also known as encrypted information...
letter always being substituted for a
plaintextIn cryptography, plaintext is information a sender wishes to transmit to a receiver. Cleartext is, sometimes confusingly, 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 1500s.
In the mid-1400s, a new technique was invented by
AlbertiLeon Battista Alberti was an Italian author, artist, architect, poet, priest, linguist, philosopher, and cryptographer, and general Renaissance humanist polymath...
, now known generally as
polyalphabetic cipherA 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 cipherThe 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
ciphertextIn cryptography, ciphertext is the result of 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. This result is also known as encrypted information...
, 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 BabbageCharles Babbage, FRS was an English mathematician, philosopher, inventor and mechanical engineer who originated the concept of a programmable computer. Parts of his uncompleted mechanisms are on display in the London Science Museum. In 1991, a perfectly functioning difference engine was...
,
Friedrich KasiskiMajor Friedrich Wilhelm Kasiski was a Prussian infantry officer, cryptographer and archeologist. Kasiski was born in Schlochau, West Prussia .-Military service:...
, and
William F. FriedmanWilliam Frederick Friedman was a US Army cryptographer . He 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
alphabetAn alphabet is a standardized set of letters basic written symbols or graphemes each of which roughly 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...
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
typewriterA typewriter is a mechanical or electromechanical device with a set of "keys" that, when pressed, cause characters to be printed on a medium, usually paper...
, 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 an
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 alphabetThe Latin alphabet, also called the Roman alphabet, is the most widely used alphabetic writing system in the world today. It evolved from the western variety of the Greek alphabet called the Cumaean alphabet, and was initially developed by the ancient Romans to write the Latin language.During the...
) 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 machineAn Enigma machine is any of a family of related electro-mechanical rotor machines used for the encryption and decryption of secret messages. The first 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
involutionIn mathematics, an involution, or an involutary function, is a function that is its own inverse, so that-General properties:Any involution is a bijection.The identity map is a trivial example of an 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 officersThe Koninklijke Marine is the navy of the Netherlands.-Bases:The main naval base is Den Helder, Noord Holland.Secondary naval bases are in Amsterdam, Vlissingen, Texel and Willemstad...
, 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 HebernEdward Hugh Hebern was an early inventor of rotor machines, devices for encryption.-Background:Hebern was born in Streator, Illinois on April 23, 1869. He was brought up in the Soldiers' Orphan Home in Bloomington. At the age of 14, he lived and worked on a farm near Odin. Later, he became a...
, Arvid Damm,
Hugo KochHugo 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 ScherbiusArthur 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 and his father was a small businessman...
.
In the
United StatesThe 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 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...
, 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. FriedmanWilliam Frederick Friedman was a US Army cryptographer . He 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 ArmyThe United States Army is the branch of the United States Military responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military and is one of seven uniformed services...
's
SISThe 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 KochHugo 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
patentA patent is a set of exclusive rights granted by a state to an inventor or their assignee for a limited period of time in exchange for a public disclosure of an invention....
on a rotor machine in 1919. At about the same time in
SwedenSweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe...
,
Arvid Gerhard DammArvid 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 ScherbiusArthur 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 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 machineAn Enigma machine is any of a family of related electro-mechanical rotor machines used for the encryption and decryption of secret messages. The first Enigma was invented by German engineer Arthur Scherbius at the end of World War I...
.
The Enigma machine
- Main article: Enigma machine
An Enigma machine is any of a family of related electro-mechanical rotor machines used for the encryption and decryption of secret messages. The first Enigma was invented by German engineer Arthur Scherbius at the end of World War I...
The most widely known rotor cipher device is the German
Enigma machineAn Enigma machine is any of a family of related electro-mechanical rotor machines used for the encryption and decryption of secret messages. The first 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
ciphertextIn cryptography, ciphertext is the result of 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. This result is also known as encrypted information...
.
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 EnigmaCryptanalysis of the Enigma enabled the Allies in World War II to read substantial amounts of secret Morse-coded radio communications of the Axis powers enciphered using Enigma machines...
.)
Scherbius joined forces with a mechanical engineer named Ritter and formed Chiffriermaschinen AG in
BerlinBerlin is the capital city and one of sixteen states of Germany. With a population of 3.4 million within its city limits, Berlin is Germany's largest city. It is the second most populous city and the eighth 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' is the capital and largest city of Sweden. It is the site of the national Swedish government, the Riksdag , and the official residence of the Swedish Monarch as well as the prime minister. The Monarch resides at Drottningholm Palace outside of Stockholm since 1980 and uses the Royal Palace of...
. 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 NavyThe Kriegsmarine was the name of the German Navy between 1935 and 1945, during the Nazi regime, superseding the Reichsmarine, and the Kaiserliche Marine of World War I. The Kriegsmarine was one of three official branches of the Wehrmacht.-Command structure:Adolf Hitler was the commander-in-chief...
adopted Enigma in 1926, and the
German ArmyThe 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
SDThe Sicherheitsdienst was primarily the intelligence service 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 Gestapo, which the SS had infiltrated heavily...
.
The
PolesPoland , officially the Republic of Poland , is a country in Central Europe . Poland is 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
ParisParis is the capital of France and the country's most populous city. It is 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
LuftwaffeLuftwaffe 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 1933 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956.Schweizer Luftwaffe is also the name of the Swiss Air...
Enigma traffic — until work at Station
PC BrunoPC 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-boatU-boat is the anglicized version of the German word , 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 AtlanticThe Battle of the Atlantic was the longest continuous military campaignof World War II,...
.
Various machines
During
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into 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 T52The 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 codeThe 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...
. The Allies developed the
TypexIn 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
SIGABAIn the history of cryptography, the ECM Mark II was a rotor machine used by the United States from World War II until the 1950s. The machine was also known as the SIGABA or Converter M-134 by the Army, or CSP-888/889 by the Navy, and a modified Navy version was termed the CSP-2900.Like many...
(American). During the War the
SwissSwitzerland , officially the Swiss Confederation , is a federal republic consisting of 26 states named cantons, with Bern as the seat of the federal authorities...
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
PURPLEIn 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 switchIn 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 axis...
es, but was conceptually similar.
Rotor machines continued to be used even in the computer age. The
KL-7The TSEC/KL-7, code named ADONIS, was a rotor machine encryption system introduced in the 1950s by the U.S. National Security Agency. It had eight rotors, seven of which moved in a complex pattern. The non-moving rotor was in the middle of the stack. It replaced the SIGABA system developed during...
(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
CanadianCanada is a country occupying most of northern North America, extending 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.
A unique rotor machine was constructed in 2002 by
NetherlandsThe Netherlands is a country in Northwestern Europe, constituting the major portion of the Kingdom of the Netherlands. It is a parliamentary democratic constitutional monarchy. The Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east...
-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
cryptIn 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
UNIXUnix is a 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 Machine
The 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 machine
An Enigma machine is any of a family of related electro-mechanical rotor machines used for the encryption and decryption of secret messages. The first Enigma was invented by German engineer Arthur Scherbius at the end of World War I...
- Lorenz SZ 40/42
- 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...
- 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 punch card mechanism. "Fialka" means "violet" in Russian...
- 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...
- HX-63
The 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-7
The TSEC/KL-7, code named ADONIS, was a rotor machine encryption system introduced in the 1950s by the U.S. National Security Agency. It had eight rotors, seven of which moved in a complex pattern. The non-moving rotor was in the middle of the stack. It replaced the SIGABA system developed during...
- Lacida
The 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-325
In 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...
- Mercury
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....
- NEMA
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 cryptograph
The 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...
- Portex
Portex 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:...
- RED
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...
- SIGABA
In the history of cryptography, the ECM Mark II was a rotor machine used by the United States from World War II until the 1950s. The machine was also known as the SIGABA or Converter M-134 by the Army, or CSP-888/889 by the Navy, and a modified Navy version was termed the CSP-2900.Like many...
- SIGCUM
SIGCUM, also known as Converter M-228, was a rotor cipher machine used to encrypt teletype 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...
- BID/60
BID/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)
- 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....
External links