Marian Rejewski (probably 1932, the year he first solved the Enigma machine).
Courtesy of Janina Sylwestrzak, Rejewski's daughter.

Marian Adam Rejewski (['marjan re'jefski] (help· info); 16 August 1905 – 13 February 1980) was a Polish mathematician and cryptologist who, in 1932, solved the Enigma machine, the main cipher device used by Germany. The success of Rejewski and his colleagues jump-started British reading of Enigma in World War II, and the intelligence so gained, code-named "Ultra", contributed, perhaps decisively, to the defeat of Nazi Germany^{(Note 1)}. ImageMetadata File history File links MR_1932_small. ... ImageMetadata File history File links MR_1932_small. ... The plugboard, keyboard, lamps and finger-wheels of the rotors emerging from the inner lid of a three-rotor German military Enigma machine (version with labels) For other uses, see Enigma. ... Image File history File links Rejewski. ... August 16 is the 228th day of the year (229th in leap years) in the Gregorian Calendar. ... 1905 (MCMV) was a common year starting on Sunday (see link for calendar). ... February 13 is the 44th day of the year in the Gregorian calendar. ... 1980 (MCMLXXX) was a leap year starting on Tuesday. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... The German Lorenz cipher machine, used in World War II for encryption of very high-level general staff messages Cryptography (or cryptology; derived from Greek κρυπτός kryptós hidden, and γράφειν gráfein to write) is the study of message secrecy. ... The plugboard, keyboard, lamps and finger-wheels of the rotors emerging from the inner lid of a three-rotor German military Enigma machine (version with labels) For other uses, see Enigma. ... This article is about algorithms for encryption and decryption. ... Combatants Major Allied powers: United Kingdom Soviet Union United States Republic of China and others Major Axis powers: Nazi Germany Italy Japan and others Commanders Winston Churchill Joseph Stalin Franklin Roosevelt Harry Truman Chiang Kai-Shek Adolf Hitler Benito Mussolini Hideki Tojo Casualties Military dead: 17,000,000 Civilian dead... Military intelligence (abbreviated MI, int [Commonwealth], or intel [U.S.]), is a military discipline that focuses on information gathering, analysis, and dissemination about enemy units, terrain, and the weather in an area of operations. ... Ultra (sometimes capitalized ULTRA) was the name used by the British for intelligence resulting from decryption of German communications in World War II. The term eventually became the standard designation in both Britain and the United States for all intelligence from high-level cryptanalytic sources. ... The raising of the Red Flag over the Reichstag in Berlin, May 1945. ...

While studying mathematics at Poznań University, Rejewski had attended a secret cryptology course conducted by the Polish General Staff's Cipher Bureau, which he joined full-time in 1932. The Bureau had achieved little success reading Enigma and in late 1932 set Rejewski to work on the problem. After only a few weeks, he deduced the secret internal wiring of the Enigma. Rejewski and two mathematician colleagues then developed an assortment of techniques for the regular decryption of Enigma messages. Rejewski's contributions included devising the cryptologic "card catalog", derived using his "cyclometer", and the "bomba". The University of PoznaÅ„ (Polish: Uniwersytet im. ... Cryptology is an umbrella term for cryptography and cryptanalysis. ... A General Staff is a group of professional military officers who act in a staff or administrative role under the command of a general officer. ... The Biuro Szyfrów ( (?), Polish for Cipher Bureau) was the Polish agency concerned with cryptology between World Wars I and II. The Bureau enjoyed notable successes against Soviet cryptography during the Polish-Soviet War, helping to preserve Polands independence. ... This article is about algorithms for encryption and decryption. ... The card catalog, or catalog of characteristics, in cryptology, was a system designed, and first completed about 1935, by Polish Cipher Bureau mathematician-cryptologist Marian Rejewski to facilitate decrypting German Enigma messages. ... Diagram of cyclometer, from Marian Rejewski’s papers The cyclometer was a cryptologic device designed by the Polish Cipher Bureau (BS-4) to help decrypt the German Enigma machine during the 1930s. ... Cryptologic bomb. ...

Five weeks before the German invasion of Poland in 1939, Rejewski and his colleagues presented their results on Enigma decryption to French and British intelligence representatives. Shortly after the outbreak of war, the Polish cryptologists were evacuated to France, where they continued their work in collaboration with the British and French. They were again compelled to evacuate after the fall of France in June 1940, but within months returned to work undercover in Vichy France. After the country was fully occupied by Germany in November 1942, Rejewski and fellow mathematician Henryk Zygalski fled, via Spain, Portugal and Gibraltar, to Britain. There they worked at a Polish Army unit, solving low-level German ciphers. In 1946 Rejewski returned to his family in Poland and worked as an accountant, remaining silent about his cryptologic work until 1967. Combatants Poland Nazi Germany Soviet Union Slovakia Commanders Edward Rydz-Śmigły Fedor von Bock (Army Group North) Gerd von Rundstedt (Army Group South) Mikhail Kovalov (Belorussian Front) Semyon Timoshenko (Ukrainian Front) Ferdinand Čatloš (Field Army Bernolak) Strength Poland: 39 divisions 16 brigades 4,300 guns 880 tanks 400 aircraft... Military intelligence (abbreviated MI, int [Commonwealth], or intel [U.S.]), is a military discipline that focuses on information gathering, analysis, and dissemination about enemy units, terrain, and the weather in an area of operations. ... In World War II, Battle of France or Case Yellow (Fall Gelb in German) was the German invasion of France and the Low Countries, executed 10 May 1940 which ended the Phony War. ... For other uses of Vichy, see Vichy (disambiguation). ... Henryk Zygalski, about 1930. ...

Education and early work

Rejewski's Master of Philosophy diploma in mathematics, Poznań University, March 1, 1929.

Warsaw's Saxon Palace, where the Biuro Szyfrów was housed in 1932, when Rejewski began his work on Enigma.

Marian Rejewski was born August 16, 1905, in Bydgoszcz.^{(Note 2)} His parents were Józef, a cigar merchant, and Matylda, née Thoms. He attended a German-speaking Königliches Gymnasium zu Bromberg (Royal Grammar School in Bydgoszcz) and completed high school with his matura in 1923. Rejewski then studied mathematics at Poznań University, graduating on March 1, 1929. Image File history File links Download high resolution version (545x800, 101 KB) This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... Image File history File links Download high resolution version (545x800, 101 KB) This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... For other meanings of mathematics or math, see mathematics (disambiguation). ... The University of PoznaÅ„ (Polish: Uniwersytet im. ... March 1 is the 60th day of the year in the Gregorian calendar (61st in leap years). ... 1929 (MCMXXIX) was a common year starting on Tuesday (link will take you to calendar). ... Image File history File links Palac_Saski_(2). ... Image File history File links Palac_Saski_(2). ... Rendering of the Saxon Palace, as it is to be rebuilt. ... The Biuro Szyfrów ( (?), Polish for Cipher Bureau) was the Polish agency concerned with cryptology between World Wars I and II. The Bureau enjoyed notable successes against Soviet cryptography during the Polish-Soviet War, helping to preserve Polands independence. ... In the history of cryptography, the Enigma was a portable cipher machine used to encrypt and decrypt secret messages. ... August 16 is the 228th day of the year (229th in leap years) in the Gregorian Calendar. ... 1905 (MCMV) was a common year starting on Sunday (see link for calendar). ... Bydgoszcz ( ; German: ; Latin: Bydgostia) is a city in northern Poland, on the Brda and Vistula rivers, with a population of 369,151 (2004). ... Four cigars of different brands (from top: H. Upmann, Montecristo, Macanudo, Romeo y Julieta) An airtight cigar storage tube and a double guillotine-style cutter A cigar is a tightly rolled bundle of dried and fermented tobacco, one end of which is ignited so that its smoke may be drawn... Bydgoszcz ( ; German: ; Latin: Bydgostia) is a city in northern Poland, on the Brda and Vistula rivers, with a population of 369,151 (2004). ... Matura (Matur, Maturita) is the word commonly used in Austria, Bosnia and Herzegovina, Bulgaria, Croatia, Italy, Liechtenstein, Poland, Serbia, Slovenia and Switzerland for the final exams young adults (aged 18 or 19) take at the end of their secondary education. ... For other meanings of mathematics or math, see mathematics (disambiguation). ... The University of PoznaÅ„ (Polish: Uniwersytet im. ... March 1 is the 60th day of the year in the Gregorian calendar (61st in leap years). ... 1929 (MCMXXIX) was a common year starting on Tuesday (link will take you to calendar). ...

In early 1929, shortly before he graduated, Rejewski started attending a secret cryptology course organized for selected German-speaking mathematics students by the Polish General Staff's Cipher Bureau (Biuro Szyfrów). Rejewski and fellow students Henryk Zygalski and Jerzy Różycki were among the few who could keep up with the course while balancing the demands of their normal studies. The Biuro Szyfrów ( (?), Polish for Cipher Bureau) was the Polish agency concerned with cryptology between World Wars I and II. The Bureau enjoyed notable successes against Soviet cryptography during the Polish-Soviet War, helping to preserve Polands independence. ... Henryk Zygalski, about 1930. ... Jerzy Różycki, about 1928. ...

Rejewski graduated with a master's degree in mathematics on 1 March 1929; his thesis was titled, "Theory of double periodic functions of the second and third kind and its applications." A few weeks later, he began the first year of a two-year actuarial statistics course at Göttingen, Germany. He would not complete the course, for, while home for the summer in 1930, he accepted the offer of a mathematics teaching assistantship at Poznań University. At the same time, he also began working part-time for the Cipher Bureau, which by then had concluded the cryptology course and set up an outpost at Poznań to decrypt intercepted German radio messages. Rejewski worked some twelve hours a week near the Mathematics Institute in an underground vault referred to puckishly as the "Black Chamber".^[1] March 1 is the 60th day of the year in the Gregorian calendar (61st in leap years). ... Damage from Hurricane Katrina. ... Göttingen ( ) is a city in Lower Saxony, Germany. ... The University of PoznaÅ„ (Polish: Uniwersytet im. ...

In the summer of 1932, the Poznań branch of the Cipher Bureau was disbanded. On September 1, 1932, as a civilian employee, Rejewski joined the Cipher Bureau at the General Staff building (the Saxon Palace) in Warsaw, as did Zygalski and Różycki. September 1 is the 244th day of the year (245th in leap years) in the Gregorian calendar. ... 1932 (MCMXXXII) was a leap year starting on Friday (the link will take you to a full 1932 calendar). ... Rendering of the Saxon Palace, as it is to be rebuilt. ... Warsaw (Polish: , , in full The Capital City of Warsaw, Polish: Miasto StoÅ‚eczne Warszawa) is the capital of Poland and its largest city. ...

Their first assignment was to work out a four-letter code used by the Kriegsmarine (German Navy). Progress on solving this system was initially slow, but sped up considerably after a test coded-message exchange was received—a six-group signal, followed by a four-group response. The cryptologists guessed correctly that the first signal was the question, "When was Frederick the Great born?" followed by the response, "1712."^[2] In the context of cryptography, a code is a method used to transform a message into an obscured form, preventing those not in on the secret from understanding what is actually transmitted. ... The Kriegsmarine (or War Navy) was the name of the German Navy between 1935 and 1945, during the Nazi regime, superseding the Reichsmarine. ... Frederick the Great Frederick II of Prussia (Friedrich der Große, Frederick the Great, January 24, 1712 – August 17, 1786) was the Hohenzollern king of Prussia 1740–86. ...

The Enigma machine

In October 1932, while work on the Naval code was still underway, Rejewski was set to work, alone and in secret, on the output of the new standard German cipher machine, the Enigma I, which was coming into widespread use. While the Cipher Bureau had, by later report, succeeded in solving an earlier, plugboard-less Enigma^{(Note 3)}, it had had no success with the Enigma I^[3]. The plugboard, keyboard, lamps and finger-wheels of the rotors emerging from the inner lid of a three-rotor German military Enigma machine (version with labels) For other uses, see Enigma. ...

The Enigma machine, solved by Rejewski in 1932, was widely used by Germany's military services to secure their communications.

The Enigma machine was an electromechanical device, equipped with a 26-letter keyboard and a set of 26 lamps, corresponding to the letters of the alphabet. Inside was a set of wired drums ("rotors" and a "reflector") that scrambled the input. The machine also featured a plugboard to swap pairs of letters. To encipher a letter, the operator pushed the relevant key and noted down which of the lamps lit. Each key press caused one or more rotors to advance, and thus the encipherment varied from one key press to the next. In order for two operators to communicate, both Enigma machines had to be set up in exactly the same way. The large number of possibilities for setting the rotors and the plugboard combined to form an astronomical number of configurations, each of which would produce a different cipher. The settings were changed daily, with the consequence that the machine had to be "broken" anew each day if the messages were to be read continually. Image File history File links Download high resolution version (1414x1886, 745 KB) Enigma Machine at the Imperial War Museum, London. ... Image File history File links Download high resolution version (1414x1886, 745 KB) Enigma Machine at the Imperial War Museum, London. ... The plugboard, keyboard, lamps and finger-wheels of the rotors emerging from the inner lid of a three-rotor German military Enigma machine (version with labels) For other uses, see Enigma. ... In engineering, electromechanics combines electromagnetism and mechanics. ... an index typewriter with a circular keyboard The 1874 Sholes & Glidden typewriters established the QWERTY layout for the letter keys that is used nowadays in Anglophone countries for virtually all computer keyboards and the majority of other keyboards. ... The Latin alphabet, also called the Roman alphabet, is the most widely used alphabetic writing system in the world today. ... In cryptography, a rotor machine is a electro-mechanical device used for encrypting and decrypting secret messages. ... A reflector, in cryptology, is a component of some rotor cipher machines, such as the Enigma machine, that sends electrical impulses that have reached it from the machines rotors, back in reverse order through those rotors. ... In cryptography, a plugboard (sometimes stecker or comutator) was a component of certain rotor machines, including some Enigma models, that exchanged letters of the alphabet. ...

To decrypt Enigma messages, three pieces of information were needed:

1. A general understanding of how Enigma functioned
2. The wiring of the rotors
3. The daily settings: the sequence and orientations of the rotors (of which there were three initially), and the plug connections on the plugboard

Rejewski had only the first at his disposal, based on information already acquired by the Cipher Bureau^[4].

Solution of the Enigma wiring

A cycle formed by the first and fourth letters of a set of indicators. Rejewski exploited these cycles to deduce the Enigma rotor wiring in 1932, and thereafter to solve the daily message settings.

First, Rejewski tackled the problem of finding the wiring of the rotors. To do this, he pioneered the use of pure mathematics in cryptanalysis. Previous methods had largely exploited linguistic patterns and the statistics of natural-language texts — letter-frequency analysis. Rejewski, however, applied techniques from group theory — theorems about permutations — in his attack on Enigma. These mathematical techniques, combined with material supplied by French military intelligence, enabled him to reconstruct the internal wirings of the machine's rotors and nonrotating reflector. "The solution", historian David Kahn writes, "was Rejewski's own stunning achievement, one that elevates him to the pantheon of the greatest cryptanalysts of all time"^[5]. Rejewski used a mathematical theorem that one mathematics professor has since described as "the theorem that won World War II"^[6]. Image File history File links Download high resolution version (800x689, 25 KB) A 4-cycle formed from the first and fourth letters of four Enigma message indicators, as used before 1938 by the German military. ... Image File history File links Download high resolution version (800x689, 25 KB) A 4-cycle formed from the first and fourth letters of four Enigma message indicators, as used before 1938 by the German military. ... Let be a set. ... Broadly speaking, pure mathematics is mathematics motivated entirely for reasons other than application. ... Cryptanalysis (from the Greek kryptós, hidden, and analýein, to loosen or to untie) is the study of methods for obtaining the meaning of encrypted information, without access to the secret information which is normally required to do so. ... Linguistics is the scientific study of language. ... A graph of a bell curve in a normal distribution showing statistics used in educational assessment, comparing various grading methods. ... The term natural language is used to distinguish languages spoken and signed (by hand signals and facial expressions) by humans for general-purpose communication from constructs such as writing, computer-programming languages or the languages used in the study of formal logic, especially mathematical logic. ... In mathematics, physics and signal processing, frequency analysis is a method to decompose a function, wave, or signal into its frequency components so that it is possible to have the frequency spectrum. ... Group theory is that branch of mathematics concerned with the study of groups. ... A theorem is a proposition that has been or is to be proved on the basis of explicit assumptions. ... Permutation is the arrangement of symbols or objects into distinguishable orderings. ... Military intelligence (abbreviated MI, int. ... David Kahn is a US historian, journalist and writer. ...

Rejewski studied the first six letters of all the Enigma messages intercepted on a single day. For security, each message sent on Enigma was encrypted using a different starting position of the three rotors, chosen by the operator. This was termed the message setting, and was three letters long. To convey this to the receiving operator, a sending operator began each message by sending the message setting in a disguised form — a six-letter indicator. The indicator was formed using the Enigma with the rotors set to a common global setting for that day, termed the ground setting, shared by all operators. Unfortunately for the Germans, the particular way the indicator was constructed introduced a fundamental weakness into the system.

For example, suppose the operator chose the message setting KYG for a message. The operator would first set the Enigma's rotors to the ground setting, which might be GBL on that particular day, and then encrypt the message setting on the Enigma twice; that is, the operator would enter KYGKYG (which might come out to something like QZKBLX). The operator would then reposition the rotors at KYG, and encrypt the actual message. A receiving operator could reverse the process to recover first the message setting, then the message itself. The repetition of the message setting was apparently meant as an error check to detect garbles, but it had the unforeseen effect of greatly weakening the cipher. Due to the indicator's repetition of the message setting, Rejewski knew that, in the plaintext of the indicator, the first and fourth letters were the same, the second and fifth were the same, and the third and sixth were the same. These relations could be exploited to break into the cipher. In telecommunication, the term garble has the following meanings: Garble in transmissions: An error in transmission, reception, encryption, or decryption that changes the text of a message or any portion thereof in such a manner that it is incorrect or undecryptable; Garble in telephone circuits: In a telephone circuit or... The plain text term has a different meaning. ...

Rejewski studied these related pairs of letters. For example, if there were four messages that had the following indicators on the same day: BJGTDN, LIFBAB, ETULZR, TFREII, then by looking at the first and fourth letters of each set, he knew that certain pairs of letters were related. B was related to T, L was related to B, E was related to L, and T was related to E: (B,T), (L,B), (E,L), and (T,E). If he had enough different messages to work with, he could build entire sequences of relationships: the letter B was related to T, which was related to E, which was related to L, which was related to B (see diagram). This was a "cycle of 4", since it took four jumps until it got back to the start letter. Another cycle on the same day might be AFWA, or a "cycle of 3". If there were enough messages on a given day, all the letters of the alphabet might be covered by a number of different cycles of various sizes. The cycles would be consistent for one day, and then would change to a different set of cycles the next day. Similar analysis could be done on the 2nd and 5th letters, and the 3rd and 6th, identifying the cycles in each case and the number of steps in each cycle.

Using the data thus gained, combined with Enigma operators' tendency to choose predictable letter combinations as indicators (such as girlfriends' initials or a pattern of keys that they saw on the Enigma keyboard), Rejewski was able to deduce six permutations corresponding to the encipherment at six consecutive positions of the Enigma machine. These permutations could be described by six equations with various unknowns, representing the wiring within the entry drum, rotors, reflector, and plugboard^[7]. Permutation is the arrangement of symbols or objects into distinguishable orderings. ... An equation is a mathematical statement, in symbols, that two things are the same. ...

Assistance from French Intelligence

At this point Rejewski ran into difficulty: the large number of unknowns made the equations complex. He would later comment in 1980 that it was still not known whether such a set of six equations was solvable without further data. But he was assisted by cryptographic documents that a section of the French intelligence organization (the Deuxième Bureau), under future General Gustave Bertrand, had obtained and passed on to the Polish Cipher Bureau. The documents had been procured from a traitor in the German cipher office, Hans-Thilo Schmidt, and included the Enigma settings for the months of September and October 1932. On December 9 or 10^{(Note 4)}, 1932, the documents were given to Rejewski, who used their information to eliminate the effect of the plugboard from the equations. With the reduced number of unknowns, solving the equations became a tractable problem. Gustave Bertrand (died 1976) was a French military intelligence officer who made a vital contribution to the decryption, by Polands Cipher Bureau, of German Enigma ciphers beginning in December 1932. ... In law, treason is the crime of disloyalty to ones nation. ... Hans Thilo-Schmidt (born 1888) was an employee at the German Armys cryptographic headquarters in the early 1930s when, shortly after the Army version of the Enigma cypher machine was introduced, he decided to make some money. ...

Another obstacle had to be overcome, however. The military Enigma had been modified from the commercial Enigma, of which Rejewski had had an actual example to study. In the commercial machine, the keys were connected to the entry drum in German keyboard order ("QWERTZU…"). However, in the military Enigma, the connections had instead been wired in alphabetical order: "ABCDEF…" This new wiring sequence foiled British codebreakers working on Enigma, who dismissed the "ABCDEF…" wiring as too obvious. Rejewski, perhaps guided by an intuition about a German fondness for order, simply guessed that the wiring was the normal alphabetic ordering. He later recalled that, after he had made this assumption, "from my pencil, as by magic, began to issue numbers designating the connections in rotor N. Thus the connections in one rotor, the right-hand rotor, were finally known"^[8].

The settings provided by French Intelligence covered two months which straddled a changeover period for the rotor ordering. A different rotor happened to be in the right-hand position for the second month, and so the wirings of two rotors could be recovered by the same method^{(Note 5)}. This simplified the analysis, and by the end of the year, the wirings of all three rotors and the reflector had been recovered. An example message in an Enigma instruction manual provided a sequence of plaintext and corresponding ciphertext enciphered at a given setting; this helped Rejewski eliminate remaining ambiguity from the wiring^[8]. The plain text term has a different meaning. ... This article is about algorithms for encryption and decryption. ...

There has been speculation as to whether the rotor wirings could have been solved without the documents supplied by French Intelligence. Rejewski recalled in 1980 that another way had been found that could have been used to achieve this, but that the method was "imperfect and tedious" and relied on chance. In 2005, mathematician John Lawrence published a paper arguing that it would have taken four years for this method to have had a reasonable likelihood of success^[9]. Rejewski wrote that "the conclusion is that the intelligence material furnished to us should be regarded as having been decisive to solution of the machine"^[8].

Methods for solving the daily Enigma settings

After Rejewski had determined the wiring in the remaining rotors, he was joined in early 1933 by Różycki and Zygalski in devising methods and equipment to break Enigma ciphers routinely^{(Note 6)}. Rejewski later recalled:

Now we had the machine, but we didn't have the keys and we couldn't very well require Bertrand to keep on supplying us with the keys every month ... The situation had reversed itself: before, we'd had the keys but we hadn't had the machine — we solved the machine; now we had the machine but we didn't have the keys. We had to work out methods to find the daily keys.^[10] A key is a piece of information that controls the operation of a cryptography algorithm. ...

Early methods

Cyclometer (mid-1930s), devised by Rejewski to catalogue the cycle structure of Enigma permutations.

A number of methods and devices had to be invented in response to continual improvements in German operating procedure and to the Enigma machine itself. The earliest method for reconstructing daily keys was the "grill", based on the fact that the plugboard's connections exchanged only six pairs of letters, leaving fourteen letters unchanged. Next was Różycki's "clock" method, which sometimes made it possible to determine which rotor was at the right-hand side of the Enigma machine on a given day.^[11] Image File history File links Download high resolution version (800x626, 82 KB) Diagram of Marian Rejewskis cyclometer (Inkscape). ... Image File history File links Download high resolution version (800x626, 82 KB) Diagram of Marian Rejewskis cyclometer (Inkscape). ... Diagram of cyclometer, from Marian Rejewski’s papers The cyclometer was a cryptologic device designed by the Polish Cipher Bureau (BS-4) to help decrypt the German Enigma machine during the 1930s. ... The grill (Polish: ruszt), in cryptology, was a method used, chiefly early on, by the mathematician-cryptologists of the Polish Cipher Bureau in decrypting German Enigma machine ciphers. ... The clock, in cryptology, was a method devised by Polish mathematician-cryptologist Jerzy Różycki, at the Polish General Staffs Cipher Bureau, to facilitate decrypting German Enigma messages. ...

After 1 October 1936, German procedure changed, increasing the number of plugboard connections. As a result, the grill method became considerably less effective. However, a method using a card catalog had been devised around 1934 or 1935, and was independent of the number of plugboard connections. The catalog was constructed using Rejewski's "cyclometer", a special-purpose device for creating a catalog of permutations. Once the catalog was complete, the permutation could be looked up in the catalog, yielding the Enigma rotor settings for that day.^[12] October 1 is the 274th day of the year (275th in leap years) in the Gregorian calendar. ... 1936 (MCMXXXVI) was a leap year starting on Wednesday (link will take you to calendar). ... The card catalog, or catalog of characteristics, in cryptology, was a system designed, and first completed about 1935, by Polish Cipher Bureau mathematician-cryptologist Marian Rejewski to facilitate decrypting German Enigma messages. ... Diagram of cyclometer, from Marian Rejewski’s papers The cyclometer was a cryptologic device designed by the Polish Cipher Bureau (BS-4) to help decrypt the German Enigma machine during the 1930s. ...

The cyclometer comprised two sets of Enigma rotors, and was used to determine the length and number of cycles of the permutations that could be generated by the Enigma machine. Even with the cyclometer, preparing the catalog was a long and difficult task. Each position of the Enigma machine (there were 17,576 positions) had to be examined for each possible sequence of rotors (there were 6 possible sequences); therefore, the catalog comprised 105,456 entries. The preparation of the catalog took over a year, but when it was ready about 1935, it made obtaining daily keys a matter of 12–20 minutes.^[13] However, on November 1 or 2, 1937, the Germans replaced the reflector in their Enigma machines, which meant that the entire catalog had to be recalculated from scratch. Nonetheless, by January 1938 the Cipher Bureau's German section was reading a remarkable 75% of Enigma intercepts, and according to Rejewski, with only a minimal increase in personnel, this could easily have been increased to 90%.^[14] A reflector, in cryptology, is a component of some rotor cipher machines, such as the Enigma machine, that sends electrical impulses that have reached it from the machines rotors, back in reverse order through those rotors. ...

Rejewski's bomba and Zygalski's sheets

Cryptologic bomb.
1: Rotors (for clarity, only one 3-rotor set is shown).
2: Electric motor.
3: Switches.

In 1937 Rejewski, along with the German section of the Cipher Bureau, transferred to a secret facility near Pyry in the Kabaty Woods south of Warsaw. On September 15, 1938, new rules for enciphering message keys (a new "indicator procedure") were put into effect by the Germans, making the techniques then in use obsolete.^{(Note 7)} The Polish cryptanalysts rapidly responded with new techniques. One was Rejewski's bomba, an electrically powered aggregate of six Enigmas, which enabled the daily keys to be solved in about two hours. Six bombas were built and ready for use by mid-November 1938.^[15] The bomba exploited the fact that the plugboard connections did not affect all the letters; therefore, when another change to German operating procedure occurred on 1 January 1939, increasing the number of plugboard connections, the usefulness of the machines was greatly reduced. The British bombe, the main tool that would be used to break Enigma messages during World War II, would be named after, and likely inspired by, the Polish bomba, although the cryptanalytic methods embodied by the two machines were very different.^[16] Image File history File links Download high resolution version (445x640, 65 KB) Description: 1: Rotors (for clarity, only one 3-rotor set is shown). ... Image File history File links Download high resolution version (445x640, 65 KB) Description: 1: Rotors (for clarity, only one 3-rotor set is shown). ... Cryptologic bomb. ... Pyry ( (?)) is one of the southernmost neighborhoods of the city of Warsaw. ... Kabaty is the southernmost neighborhood of the city of Warsaw, located in its Ursynów district. ... September 15 is the 258th day of the year (259th in leap years). ... 1938 (MCMXXXVIII) was a common year starting on Saturday (link will take you to calendar). ... Cryptologic bomb. ... January 1 is the first day of the calendar year in both the Julian and Gregorian calendars. ... 1939 (MCMXXXIX) was a common year starting on Sunday (link will take you to calendar). ... The Bombe replicated the action of several Enigma machines wired together. ...

A manual method was invented around the same time by Zygalski, that of "perforated sheets" ("Zygalski sheets"), which was independent of the number of plugboard connections. However, application of both the bomba and Zygalski's sheets was complicated by yet another change to the Enigma machine on 15 December 1938. The Germans had supplied Enigma operators with an additional two rotors to supplement the original three, and this increased the complexity of decryption tenfold. Building ten times as many bombes was beyond the Biuro's ability—that many bombes would have cost fifteen times their entire annual equipment budget. The following month, things became even worse when the number of plugboard cables increased from six to ten. Instead of twelve letters being swapped before entering the rotor scrambler, there were now twenty swapped letters, reducing the effectiveness of the bomba and increasing the number of possible plugboard settings by more than a thousandfold.^[17] The method of perforated sheets was a codebreaking technique used against the Enigma machine (see Cryptanalysis of the Enigma). ... December 15 is the 349th day of the year (350th in leap years) in the Gregorian calendar. ... 1938 (MCMXXXVIII) was a common year starting on Saturday (link will take you to calendar). ...

Results given to the British and French

The 1979 Polish film Sekret Enigmy (The Enigma Secret) reenacted the Polish Enigma story. Here Rejewski (left, played by Tadeusz Borowski) explains the working of the Enigma machine to British and French representatives at the July 1939 meeting at Pyry, south of Warsaw.

As it became clear that war was imminent and Polish resources were insufficient to keep pace with the evolution of Enigma encryption (ie due to the Poles' difficulty in producing in time the required 60 series of "Zygalski sheets"), the Polish General Staff and government decided to let their Western allies in on the secret. The Polish methods were revealed to British and French intelligence representatives in a meeting at Pyry on 26 July 1939.^[18] Image File history File linksMetadata SekretEnigmyRejewski. ... Image File history File linksMetadata SekretEnigmyRejewski. ... // Directors Józef Arkusz Stanisław Bareja Aleksander Ford Wojciech Has Agnieszka Holland Jerzy Hoffman Jerzy Kawalerowicz Krzysztof Kieślowski -- The Three Colors trilogy, The Decalogue Jan Jakub Kolski Kazimierz Kutz Andrzej Munk Marek Piwowski Roman Polański Ladislas Starevich Wladyslaw Starewicz Andrzej Wajda Krzysztof Zanussi Andrzej Zulawski Actors and... Pyry ( (?)) is one of the southernmost neighborhoods of the city of Warsaw. ... Warsaw (Polish: , , in full The Capital City of Warsaw, Polish: Miasto Stołeczne Warszawa) is the capital of Poland and its largest city. ... The method of perforated sheets was a codebreaking technique used against the Enigma machine (see Cryptanalysis of the Enigma). ... Pyry ( (?)) is one of the southernmost neighborhoods of the city of Warsaw. ... July 26 is the 207th day (208th in leap years) of the year in the Gregorian Calendar, with 158 days remaining. ... 1939 (MCMXXXIX) was a common year starting on Sunday (link will take you to calendar). ...

The Poles' gift of Enigma decryption to their Western allies, a month before the outbreak of World War II, came not a moment too soon. Knowledge that the cipher was crackable was a morale boost to Allied cryptanalysts. The British were able to manufacture at least two complete sets of perforated sheets—they sent one to PC Bruno, outside Paris, in mid-December 1939—and began reading Enigma within months of the outbreak of war. PC Bruno was the code name for the intelligence station operated at a farmhouse in the west of France to which French cryptanalysts retired after Paris was captured by the Germans in 1940. ...

Without the Polish assistance, British code-breakers would, at the very least, have been considerably delayed in reading Enigma. Author Hugh Sebag-Montefiore concludes that substantial breaks into German Army and Air Force Enigma ciphers by the British would have occurred only after November 1941 at the earliest, after an Enigma machine and key lists had been captured, and similarly Naval Enigma only after late 1942.^[19] Former Bletchley Park cryptologist Gordon Welchman goes further, writing that the Army and Air Force Enigma section, Hut 6, "would never have gotten off the ground if we had not learned from the Poles, in the nick of time, the details both of the German military ... Enigma machine, and of the operating procedures that were in use".^[20] During World War II, codebreakers at Bletchley Park solved messages from a large number of Axis code and cipher systems, including the German Enigma machine. ... William Gordon Welchman (15 June 1906–8 October 1985) was a British mathematician and World War II codebreaker at Bletchley Park. ... Hut 6 at Bletchley Park in 2004 Hut 6 was a wartime section of Bletchley Park tasked with the solution of German Army and Air Force Enigma machine ciphers. ...

Intelligence gained from solving high-level German ciphers—intelligence codenamed "Ultra" by the British and Americans—came chiefly from Enigma decrypts. While the exact contribution of Ultra intelligence to Allied victory is disputed, Kozaczuk and Straszak note that "it is widely believed that Ultra saved the world at least two years of war and possibly prevented Hitler from winning."^[21] The English historian Sir Harry Hinsley, who worked at Bletchley Park, similarly assessed it as having "shortened the war by not less than two years and probably by four years". ^[22] The availability of Ultra was due in large part to the early Polish work on Enigma. Ultra (sometimes capitalized ULTRA) was the name used by the British for intelligence resulting from decryption of German communications in World War II. The term eventually became the standard designation in both Britain and the United States for all intelligence from high-level cryptanalytic sources. ... Adolf Hitler Adolf Hitler (April 20, 1889 – April 30, 1945, standard German pronunciation in the IPA) was the Führer (leader) of the National Socialist German Workers Party (Nazi Party) and of Nazi Germany from 1933 to 1945. ... Sir Francis Harry Hinsley (26 November 1918–16 February 1998) was an English historian and cryptanalyst who worked at Bletchley Park during the Second World War and wrote widely on the history of international relations and British Intelligence during the Second World War. ...

Work in France and Britain

PC Bruno

In September 1939 after the outbreak of World War II, Rejewski and his fellow Cipher Bureau workers were evacuated from Poland to Romania. Rejewski, together with Zygalski and Różycki, managed to avoid being interned in a refugee camp and made their way to Bucharest, where they contacted the British embassy. Having been told by the British to "come back in a few days", they next tried the French embassy, introducing themselves as "friends of Bolek" (Bertrand's code name). The French army officer on duty called Paris for instructions and immediately had the three mathematicians evacuated to France. They arrived in Paris by the end of September.^[23]. Combatants Poland Germany Soviet Union Slovakia Commanders Edward Rydz-ÅšmigÅ‚y Fedor von Bock (Army Group North) Gerd von Rundstedt (Army Group South) Ferdinand ÄŒatloÅ¡ (Field Army Bernolak) Strength 39 divisions 16 brigades 4,300 guns 880 tanks 400 aircraft Total: 1,000,000[1] 56 German divisions, 33+ Soviet... Status Capital of Romania Mayor Adriean Videanu, since 2005 Area 228 km² Population (2003) 1,929,615[1] Density 9131. ...

On 20 October they resumed their work on German ciphers at a joint French-Polish-Spanish radio intelligence unit stationed at Château de Vignolles, forty kilometers northeast of Paris, code-named "PC Bruno". Enigma keys were being broken again by December 1939 or January 1940. The staff at PC Bruno collaborated by teletype with their opposite numbers at Bletchley Park in England. For communications security the allied Polish, French and British cryptological agencies used the Enigma machine itself closing Bruno's Enigma-encrypted messages to Britain with an ironic "Heil Hitler!"^[24]. On 24 June 1940, Bruno was disbanded after Germany's victory in the Battle of France, and Rejewski and his colleagues were evacuated to Algeria. October 20 is the 293rd day of the year (294th in leap years) in the Gregorian Calendar, with 72 days remaining. ... PC Bruno was the code name for the intelligence station operated at a farmhouse in the west of France to which French cryptanalysts retired after Paris was captured by the Germans in 1940. ... A teleprinter (teletypewriter, teletype or TTY) is a now largely obsolete electro-mechanical typewriter which can be used to communicate typed messages from point to point through a simple electrical communications channel, often just a pair of wires. ... The Hitler salute (Hitlergruß) is the embodiment of the Hitler cult of personality. ... June 24 is the 175th day of the year (176th in leap years) in the Gregorian Calendar, with 190 days remaining. ... Year 1940 (MCMXL) was a leap year starting on Monday (the link is to a full 1940 calendar). ... Combatants France United Kingdom Canada Czechoslovakia Poland Belgium Netherlands Luxembourg Germany Italy Commanders Maurice Gamelin, Maxime Weygand (French) Lord Gort (British Expeditionary Force) H.G. Winkelman (Dutch) Gerd von Rundstedt (Army Group A) Fedor von Bock (Army Group B) Wilhelm von Leeb (Army Group C) H.R.H. Umberto di...

Cadix

Rejewski (right) with colleagues Henryk Zygalski (left) and Jerzy Różycki in the gardens at Cadix (photo taken between September 1940 and June 1941).

During September 1940 they returned to work in secret in unoccupied southern (Vichy) France. Rejewski's cover was as Pierre Ranaud, a lycée professor from Nantes. A radio intelligence station was set up at the Château des Fouzes near Uzès, code-named "Cadix". Cadix began operations on 1 October. Rejewski and his colleagues solved German telegraph ciphers, and also the Swiss version of the Enigma machine (which had no plugboard). Rejewski may have had little or no involvement in working on German Enigma at Cadix ^{(Note 8)}. Image File history File links Zygalski-rozycki-rejewski. ... Image File history File links Zygalski-rozycki-rejewski. ... Henryk Zygalski, about 1930. ... Jerzy Różycki, about 1928. ... PC Bruno was the code name for the intelligence station operated at a farmhouse in the west of France to which French cryptanalysts retired after Paris was captured by the Germans in 1940. ... In France, secondary education is divided into two schools: the collège (IPA: ) (somewhat comparable to U.S. junior high school) for the first four years directly following primary school; the lycée (IPA: ) (comparable to a U.S. high school) for the next three years. ... Traditional city flag City coat of arms Motto: (Latin: Shall Neptune favour the traveller) Coordinates : , Time Zone : CET (GMT +1) Administration Département Loire-Atlantique (44) Région Pays-de-la-Loire Mayor Jean-Marc Ayrault (PS) (since 1989) Intercommunality Urban Community of Nantes City (commune) Characteristics Land Area 65. ... Uzès is a picturesque town and commune in the Gard département, Languedoc, France, located about 15 miles north-northeast of Nîmes. ... Polish-French Cadix radio-intelligence team, southern France, 1940-1942. ... October 1 is the 274th day of the year (275th in leap years) in the Gregorian calendar. ... Optical Telegraf of Claude Chappe on the Litermont near Nalbach, Germany Telegraph and telegram redirect here. ...

In early July 1941, Rejewski and Zygalski were asked to try solving messages enciphered on the secret Polish Lacida cipher machine, which was used to secure communications between Cadix and the Polish General Staff in London. Lacida was a rotor machine based on the same cryptographic principle as Enigma, yet had never been subjected to a rigorous security analysis. The two cryptologists created consternation by breaking the first message within a couple of hours; further messages were solved in a similar way^[25]. The Lacida (or LCD) was a rotor cipher machine designed before World War II by the Polish Cipher Bureau for wartime use by Polish higher commands. ... In cryptography, a rotor machine is a electro-mechanical device used for encrypting and decrypting secret messages. ...

On January 9, 1942, Różycki, the youngest of the three mathematicians, died in the sinking of a French passenger ship as he was returning from a stint in Algeria to Cadix in southern France^[26]. January 9 is the 9th day of the year in the Gregorian calendar. ... Year 1942 (MCMXLII) was a common year starting on Thursday (the link is to a full 1942 calendar). ... Jerzy Różycki, about 1928. ... A passenger ship is a ship whose primary function is to carry passengers. ...

By summer 1942 work at Cadix was becoming dangerous, and plans for evacuation were drawn up. Vichy France itself was liable to be occupied by German troops, and Cadix's radio transmissions were increasingly at risk of detection by the Funkabwehr, a German unit tasked with locating enemy radio transmitters. Indeed, on 6 November a pickup truck equipped with a circular antenna arrived at the gate of the chateau where the cryptologists were operating. The visitors, however, did not enter, and merely investigated — and terrorized — nearby farms. Nonetheless, the order to evacuate Cadix was given, and this was done by 9 November. The Germans occupied the chateau only three days later^[27]. November 6 is the 310th day of the year (311th in leap years) in the Gregorian Calendar, with 55 days remaining. ... Mazda compact Pickup truck with extended cabin and homebuilt lumber rack. ... A Yagi-Uda beam antenna Short Wave Curtain Antenna (Moosbrunn, Austria) A building rooftop supporting numerous dish and sectored mobile telecommunications antennas (Doncaster, Victoria, Australia) An antenna or aerial is an arrangement of aerial electrical conductors designed to transmit or receive radio waves which is a class of electromagnetic waves. ... November 9 is the 313th day of the year (314th in leap years) in the Gregorian Calendar, with 52 days remaining. ...

Escape from France

The Poles were split into twos and threes. Rejewski and Zygalski were sent to Nice on 11 November, which was in a zone occupied by the Italians. They had to flee again after coming under suspicion, constantly moving or staying in hiding, to Cannes, Antibes, Nice again, Marseilles, Toulouse, Narbonne, Perpignan and Aix-les-Thermes, close to the Spanish border. City flag City coat of arms Motto: [1] (Latin: Nice the city) Location Coordinates Time Zone CET (GMT +1) Administration Country France Région Provence-Alpes-Côte dAzur Département Alpes-Maritimes (06) Intercommunality Community of Agglomeration Nice Côte dAzur Mayor Jacques Peyrat  (UMP) (since 1995... November 11 is the 315th day of the year (316th in leap years) in the Gregorian Calendar, with 50 days remaining. ... For the annual festival, see Cannes Film Festival. ... Antibes (Provençal Occitan: Antíbol in classical norm or Antibo in Mistralian norm) is a resort town of southeastern France, on the Mediterranean Sea in the Côte dAzur, located between Cannes and Nice. ... Marseilles redirects here. ... New city flag (Occitan cross) Traditional coat of arms Motto: (Occitan: For Toulouse, always more) Location Coordinates Time Zone CET (GMT +1) Administration Country France Region Midi-Pyrénées Department Haute-Garonne (31) Intercommunality Community of Agglomeration of Greater Toulouse Mayor Jean-Luc Moudenc  (UMP) (since 2004) City Statistics... Narbonne (Narbona in Catalan and in Occitan, commonly Narbo especially when referring to the Ancient Rome era) is a town and commune of southwestern France in the Languedoc-Roussillon région. ... Perpignan (French: Perpignan; Catalan Perpinyà) is a commune and the préfecture (administrative capital city) of the Pyrénées-Orientales département in southern France. ...

The plan was to smuggle themselves over the Pyrenees across into Spain. Accompanied by a local guide, Rejewski and Zygalski began their trek through the Pyrenees on 29 January 1943. They avoided German and Vichy patrols, but near midnight and near the border, their guide pulled out a pistol and demanded they hand over the rest of their money. Despite being robbed, they succeeded in reaching the Spanish side of the border, only to be arrested by Spanish security police within hours. The Poles were sent first to a prison in Séo de Urgel until 24 March, then moved to a prison at Lerida. The pair were eventually released on 4 May, after the intervention of the Polish Red Cross, and sent to Madrid^[28]. Leaving Madrid on 21 July, they made it to Portugal; from there, aboard HMS Scottish, to Gibraltar; and thence, aboard an old Dakota, to Britain, arriving 3 August 1943. Central Pyrenees. ... January 29 is the 29th day of the year in the Gregorian calendar. ... A Browning 9 millimeter Hi-Power Ordnance pistol of the French Navy, 19th century, using a Percussion cap mechanism Derringers were small and easily hidden. ... March 24 is the 83rd day of the year in the Gregorian Calendar (84th in leap years). ... La Seu Vella, the Romanesque-Gothic Cathedral of Lleida Lleida (Catalan: Lleida, Spanish: Lérida) is a city in the west of Catalonia, Spain. ... May 4 is the 124th day of the year in the Gregorian calendar (125th in leap years). ... Location Coordinates : 40° 23’N , 3°43′0″W Time Zone : CET (GMT +1) - summer: CEST (GMT +2) General information Native name Villa de Madrid (Spanish) Spanish name Villa de Madrid Founded 9th century Postal code 28001-28080 Area code 34 (Spain) + 91 (Villa de Madrid) Website http://www. ... July 21 is the 202nd day (203rd in leap years) of the year in the Gregorian Calendar, with 163 days remaining. ... The Douglas DC-3 is a fixed-wing, propeller-driven aircraft, which revolutionized air transport in the 1930s and 1940s and is generally regarded as one of the most significant transport aircraft ever made (also see Boeing 707 and Boeing 747). ... August 3 is the 215th day of the year in the Gregorian Calendar (216th in leap years), with 150 days remaining. ... Year 1943 (MCMXLIII) was a common year starting on Friday (the link is to a full 1943 calendar). ...

Marian Rejewski as second lieutenant (signals), Polish Army in Britain, in late 1943 or in 1944, some 11 or 12 years after he first broke Enigma.

Image File history File linksMetadata Download high resolution version (482x608, 99 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File linksMetadata Download high resolution version (482x608, 99 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... The plugboard, keyboard, lamps and finger-wheels of the rotors emerging from the inner lid of a three-rotor German military Enigma machine (version with labels) For other uses, see Enigma. ...

Britain

On 16 August Rejewski and Zygalski were inducted as privates into the Polish Army and employed at cracking German SS and SD hand ciphers at Boxmoor. The SS and SD ciphers were largely based on the Doppelkassettenverfahren system (a double Playfair scheme). On October 10, 1943, Rejewski was commissioned a second lieutenant, and on January 1, 1945, he was promoted to lieutenant. August 16 is the 228th day of the year (229th in leap years) in the Gregorian Calendar. ... A Private is a soldier of the lowest military rank (equivalent to Nato Rank Grades OR-1 to OR-3 depending on the force served in). ... Polish Army (Polish Wojsko Polskie) is the name applied to the military forces of Poland. ... SS or ss or Ss may be: The Schutzstaffel, a Nazi paramilitary force Steamship (SS) (ship prefix) The United States Secret Service A submarine not powered by nuclear energy (SS) (United States Navy designator), see SSN A Soviet/Russian surface-to-surface missile, as listed by NATO reporting name Shortstop... Sicherheitsdienst (SD) sleeve insignia. ... Boxmoor is a small suburb of Hemel Hempstead in Hertfordshire, England. ... The Playfair system was invented by Charles Wheatstone, who first described it in 1854. ... October 10 is the 283rd day of the year (284th in Leap years). ... Year 1943 (MCMXLIII) was a common year starting on Friday (the link is to a full 1943 calendar). ... Second Lieutenant is the lowest commissioned rank in many armed forces. ... January 1 is the first day of the calendar year in both the Julian and Gregorian calendars. ... Year 1945 (MCMXLV) was a common year starting on Monday (the link is to a full 1945 calendar). ... Lieutenant is a military, naval, paramilitary, fire service or police officer rank. ...

Enigma decryption, however, had become an exclusively British and American domain; the two mathematicians who, with their late colleague, had laid the foundations for Allied Enigma decryption were now excluded from the opportunity of making further contributions to their métier. British code-breaker Alan Stripp suggests that by that time, at Bletchley Park, "very few even knew about the Polish contribution" because of the strict secrecy and the observance of the "need-to-know" principle. Stripp comments further that "setting them to work on the Doppelkassetten system was like using racehorses to pull wagons"^[29]. Need To Know, also known as NTK, is an email newsletter, published late on Fridays, written by former Wired journalist and Irish Times columnist Danny OBrien and former Wired and Future journalist Dave Green. ...

Postwar life and recognition

Sculptural memorial to Marian Rejewski in his home city, Bydgoszcz, Poland, unveiled on the 100th anniversary of his birth (2005). This memorial strikingly resembles the one to Rejewski's contemporary, Alan Turing, at Whitworth Gardens, Manchester, England.

On November 21, 1946, Rejewski, having been discharged from the Polish Army in Britain, returned to Poland to be reunited with his wife, Irena Maria Rejewska (née Lewandowska, whom Rejewski had married on 20 June 1934) and their two children, Andrzej (born 1936) and Janina (born 1939, who would follow in her father's footsteps to become a mathematician). One option now open to Rejewski was to resume teaching mathematics at a university in Poznań or Szczecin, as suggested by his old Poznań University professor, Zdzisław Krygowski. Taking a university post, however, would have entailed yet another separation from his family and his elderly in-laws, with whom the Rejewskis were now living in Bydgoszcz. A grievous blow to Rejewski, too, soon after his return, was the death in summer 1947 of his 11-year-old son Andrzej from poliomyelitis. Instead, Rejewski took a position in Bydgoszcz as a supervisor in the sales section of a cable manufacturing plant, Kabel Polski (Polish Cable). Image File history File linksMetadata Download high resolution version (2560x1920, 1012 KB) Marian Rejewski Monument in Bydgoszcz, Poland, 2005 File links The following pages link to this file: Marian Rejewski Talk:Marian Rejewski Metadata This file contains additional information, probably added from the digital camera or scanner used to create... Image File history File linksMetadata D