An experienced M-209 operator might spend two to four seconds enciphering or deciphering each letter.
|
|
The deciphering procedure is nearly the same as for enciphering; the operator sets the enciphering-deciphering knob to "decipher", and aligns the key wheels to the same sequence as was used in enciphering. The first letter of the ciphertext is entered via the indicator disk, and the power handle is operated, advancing the key wheels and printing the decoded letter on the paper tape. When the letter "Z" is encountered, a cam causes a blank space to appear in the message, thus reconstituting the original message with spaces. Absent "Z"s can typically be interpreted by the operator, based on context.
|
|
Hallamaa was appointed captain in 1929 and major in 1939. Hallamaa published "Basic Enciphering" (Salakirjoitustaidon perusteet) in 1937 and this publication was used as a training manual within the Finnish Army. It was the first Finnish-language book on the subject.
|
|
This operator would type in the cyphertext and — as long as all the settings of the deciphering machine were identical to those of the enciphering machine — for every key press the reverse substitution would occur and the plaintext message would emerge.
|
|
Their instructors were the privy secretary Hasib Efendi and the Private Enciphering Secretary Kâmil Efendi. Hasib Efendi would give lessons in the Quran, Arabic, and Persian, while Kâmil Efendi was to teach Turkish reading and writing, Ottoman grammar, arithmetic, history, and geography.
|
|
There were special detachable wheel movement bars and their position on the drum could change, interchangeable print wheels, custom pinwheel labels, versions with One-time Tape reader instead of wheels, versions that only enciphered numbers, and many other details that influenced the enciphering process.
|
|
The German navy relied upon the re-enciphering process to ensure security, but the key used for this was not changed until 20 October and then not changed again for another three months. The actual substitution table used for enciphering was produced by a mechanical device with slides and compartments for the letters. Orders to change the key were sent out by wireless, and frequently confusion during the changeover period led to messages being sent out using the new cipher and then being repeated with the old. Key changes continued to occur infrequently, only 6 times during 1915 from March to the end of the year, but then more frequently from 1916.
|
|
For easier recognition, the number eight represented two. The initials A.J.M. represent the Chief Signal Officer General Albert J. Myer. Each disk had a control number used for accountability. A cipher disk is an enciphering and deciphering tool developed in 1470 by the Italian architect and author Leon Battista Alberti.
|
|
The security of passwords is therefore protected only by the one-way functions (enciphering or hashing) used for the purpose. Early Unix implementations limited passwords to eight characters and used a 12-bit salt, which allowed for 4,096 possible salt values. This was an appropriate balance for 1970s computational and storage costs.
|
|
After enciphering a few letters a different uppercase letter (Q) is inserted in the cryptogram and the movable disk is accordingly rotated obtaining a new combination: QRSTVXZ1234ABCDEFGILMNOP Stationary disk gklnprtuz&xysomqihfdbace; Movable disk The encipherment will resume thus: _SIFARÀ Plaintext Qlfiyky Ciphertext The same procedure will be continued with different key letters through the end of the message.
|
|
Of the five rotors, typically the first two were stationary. These provided additional enciphering without adding complexity to the rotor turning mechanisms. Their purpose was similar to the plugboard in the Enigmas, offering additional randomization that could be easily changed. Unlike Enigma's plugboard, however, the wiring of those two rotors could not be easily changed day-to-day.
|
|
Further electrical connections led from the rotors to 26 illuminated letters. When an operator, enciphering a message, pressed a key, an electric current passed through the machine and the rotors turned mechanically, but not in unison. Every time a key was pushed, the first rotor would rotate one letter. This happened 26 times until the first rotor had made a complete revolution.
|
|
The card catalog would index the cycle-length for all starting positions (except for turnovers that occurred while enciphering an indicator). The day's traffic would be examined to discover the cycles in the permutations. The card catalog would be consulted to find the possible starting positions. There are roughly 1 million possible cycle-length combinations and only 105,456 starting positions.
|
|
Cams on wheels 9 and 10 showing their raised (active) and lowered (inactive) positions. An active cam reversed the value of a bit (0→1 and 1→0). Each "Tunny" link had four SZ machines with a transmitting and a receiving teleprinter at each end. For enciphering and deciphering to work, the transmitting and receiving machines had to be set up identically.
|
|
The Beaufort cipher, created by Sir Francis Beaufort, is a substitution cipher similar to the Vigenère cipher, with a slightly modified enciphering mechanism and tableau.Franksen, Ole Immanuel, Babbage and cryptography. Or, the mystery of Admiral Beaufort's cipher. Mathematics and Computers in Simulation 35 (1993) 327-367 Its most famous application was in a rotor-based cipher machine, the Hagelin M-209.
|
|
There are two commonly used sets of initial parameters for GOST R 34.11 94. The starting vector for the both sets is H_1=0x00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000. Although the GOST R 34.11 94 standard itself doesn't specify the algorithm initial value H_1 and S-box of the enciphering transformation E, but uses the following "test parameters" in the samples sections.
|
|
The outcome of these investigations often rested on the assertion that Allied cryptanalysis could only break Enigma messages using pure statistical methods, which the Allies did not use for each possible combination. Instead the Allies used the Enigma design flaws, i.e. Enigma not enciphering a letter as itself, and the operational flaws such as German salutations and built machinery, e.g. Bombes, to facilitate decoding.
|
|
CAPTAIN MIDNIGHT AND DECODER RINGS, Stephen A. Kallis, Jr. The 1934 fan club's member's handbook included a simple substitution cipher with a resulting numeric cipher text. This was followed the next year with a membership badge or pin that included a cipher disk - enciphering the letters A-Z to numbers 1-26. Announcer Pierre Andre often talked about the virtues of the shows' products, sometimes stretching towards three minutes in length.
|
|
This was to stop the enciphering clerk from making up a starting position that was not random, for instance AAA or ABCABC. These were listed in an attached booklet. The last security measure implemented at the time, was classifying messages by grade, i.e. general, officer, staff, with fewer cryptographic resources available to personnel the further down the rank hierarchy, and progressively more power cryptography the higher rank you were.
|
|
Grand Admiral Karl Dönitz Sending a message to a U-boat usually began with Rear Admiral Dönitz (Commander of the Submarines, German: Befehlshaber der U-Boote, abbr. BdU) who maintained tight control on U-boat operations. The Officer of the watch would take the message, timestamp it, and hand it to the duty radio technician watch officer for encryption. Fifteen to twenty radiomen worked per shift enciphering and deciphering messages.
|
|
There were two components to this; setting the patterns of cams on the wheels and rotating the wheels for the start of enciphering a message. The cam settings were changed less frequently before summer 1944. The ψ wheel cams were initially only changed quarterly, but later monthly, the χ wheels were changed monthly but the motor wheel patterns were changed daily. From 1 August 1944, all wheel patterns were changed daily.
|
|
The British first detected T52 traffic in Summer and Autumn of 1942. One link was between Sicily and Libya, codenamed "Sturgeon", and another from the Aegean to Sicily, codenamed "Mackerel". Operators of both links were in the habit of enciphering several messages with the same machine settings, producing large numbers of depths. There were several (mostly incompatible) versions of the T52: the T52a and T52b (which differed only in their electrical noise suppression), T52c, T52d and T52e.
|
|
Vladímir Stepànov Vladimir Ivanovich Stepanov (1866–1896), was a dancer at the Mariinsky Theater in Saint Petersburg. His book, The Alphabet of Movements of the Human Body (French: L'Alphabet des Mouvements du Corps Humain) was published in Paris in 1892. The book describes a notation that encodes dance movements using musical notes instead of pictographs or abstract symbols. Stepanov breaks complex movements down to elementary moves made by individual body parts, enciphering these basic moves as notes.
|
|
A multiple of 100 or 1000 was represented by a modification (or "enciphering") of the sign for the number using the sign for the multiplier number. Such enciphered numerals directly represented the named place-value numerals used verbally. They continued to be used in inscriptions until the end of the 9th century. In his seminal text of 499 CE, Aryabhata devised a novel positional number system, using Sanskrit consonants for small numbers and vowels for powers of 10.
|
|
Following his work at Bell Labs in the US, Turing pursued the idea of electronic enciphering of speech in the telephone system. In the latter part of the war, he moved to work for the Secret Service's Radio Security Service (later HMGCC) at Hanslope Park. At the park, he further developed his knowledge of electronics with the assistance of engineer Donald Bayley. Together they undertook the design and construction of a portable secure voice communications machine codenamed Delilah.
|
|
St. James Press, 1999. Resistance movements in occupied Europe sabotaged communications facilities such as telegraph lines, forcing the Germans to use wireless telegraphy, which could then be intercepted by Britain. The Germans developed a highly complex teleprinter attachment (German: Schlüssel-Zusatz, "cipher attachment") that was used for enciphering telegrams, using the Lorenz cipher, between German High Command (OKW) and the army groups in the field. These contained situation reports, battle plans, and discussions of strategy and tactics.
|
|
Enciphering and deciphering using an Enigma machine A German Enigma operator would be given a plaintext message to encrypt. After setting up his machine, he would type the message on the Enigma keyboard. For each letter pressed, one lamp lit indicating a different letter according to a pseudo-random substitution determined by the electrical pathways inside the machine. The letter indicated by the lamp would be recorded, typically by a second operator, as the cyphertext letter.
|
|
Zygalski sheet 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 15 September 1938, the Germans introduced new rules for enciphering message keys (a new "indicator procedure"), making the Poles' earlier techniques obsolete. The Polish cryptanalysts rapidly responded with new techniques. One was Rejewski's ', an electrically powered aggregate of six Enigmas, which solved the daily keys within about two hours.
|
|
Retrieved July 2, 2010 whereby the two alphabets are slightly modified after each input plaintext letter is enciphered. This leads to nonlinear and highly diffused alphabets as encryption progresses. Deciphering is identical to enciphering, with the ciphertext letter being located in the "left" alphabet while the corresponding plaintext letter being read from the "right" alphabet. A detailed description of the Chaocipher algorithm is available as well as discussions of the deciphered plaintexts and the solution to Byrne's challenge.
|
|
On 15 December 1938, the German Army increased the complexity of Enigma enciphering by introducing two additional rotors (IV and V). This increased the number of possible wheel orders from 6 to 60. The Poles could then read only the small minority of messages that used neither of the two new rotors. They did not have the resources to commission 54 more bombs or produce 58 sets of Zygalski sheets. Other Enigma users received the two new rotors at the same time.
|
|
Ayşe's education took place in a study room in the Lesser Chancellery of the Yıldız Palace, together with her elder sister Şadiye Sultan. Their instructors were the privy secretary Hasib Efendi and the Private Enciphering Secretary Kâmil Efendi. Hasib Efendi would give lessons in the Quran, Arabic, and Persian, while Kâmil Efendi was to teach Turkish reading and writing, Ottoman grammar, arithmetic, history, and geography. Ayşe took her piano lessons from the hazinedar Dürrüyekta (who later became the wife of her eldest brother Şehzade Mehmed Selim).
|
|
During the German re- armament, the Navy continued to evaluate the Enigma and its key processes. A study by Lieutenant Henno Lucan, second radio officer on the battleship SMS Elsass, reported that the Naval Enigma met neither modern physical or cryptographic security. During this time, the Army (Reichswehr) suggested that the Navy use the Army Enigma. The Army's Enigma had the plug board (Enigma machine#Plugboard) which increased the number of enciphering circuits by 2 to 3 billion, and of course lost 5,213 starting positions.
|
|
Dodge would utilize human intelligence from female spies, runaway slaves and unionists living in Confederate territory. He created a Corps of Scouts for special reconnaissance from units of loyal residents of the south in the First Tennessee Cavalry and ex-slaves of the First Alabama Cavalry. He also employed more technical intelligence gathering disciplines such as signals intelligence and counterintelligence by tapping telegraph wires while enciphering the Union Army's own dispatches. He was infamously obsessed with operational security and corresponded by courier rather than telegraph.
|
|
The clock method exploited the three rotors (I, II, III) having different turnover positions. The rightmost rotor moved as each character was enciphered. At a certain position on the ring, enciphering the character would also cause the next rotor to the left to move one position (a turnover). The ring position that caused the next rotor to move was different for each rotor: rotor I advanced at the Q-R transition ("royal"); rotor II advanced at E-F ("flags"); rotor III advanced at V-W ("wave").
|
|
Members of Combined Operations Pilotage Parties clandestinely prepared detailed harbour maps, including depth soundings. An appeal for holiday pictures and postcards of Europe announced on the BBC produced over ten million items, some of which proved useful. Information collected by the French resistance helped provide details on Axis troop movements and on construction techniques used by the Germans for bunkers and other defensive installations. Many German radio messages were encoded using the Enigma machine and other enciphering techniques and the codes were changed frequently.
|
|
The second development, in 1976, was perhaps even more important, for it fundamentally changed the way cryptosystems might work. This was the publication of the paper New Directions in Cryptography by Whitfield Diffie and Martin Hellman. It introduced a radically new method of distributing cryptographic keys, which went far toward solving one of the fundamental problems of cryptography, key distribution, and has become known as Diffie–Hellman key exchange. The article also stimulated the almost immediate public development of a new class of enciphering algorithms, the asymmetric key algorithms.
|
|
In order to carefully conceal them, the other huts were given wooden exteriors and located in the wooded area to the rear of the hall on its western side. These huts were lettered A, B, C, D, E and F. The wireless listeners were uniformed women of the ATS (Auxiliary Territorial Service), who had been trained on the Isle of Man. They intercepted German and Italian messages, many of which had been enciphered on Enigma machines. It was the most difficult of signals intelligence gathering, because the enciphering meant that no prediction was possible.
|
|
The British first detected T52 traffic in the summer and autumn of 1942 on a link between Sicily and Libya, codenamed "Sturgeon", and another from the Aegean to Sicily, codenamed "Mackerel". Operators of both links were in the habit of enciphering several messages with the same machine settings, producing large numbers of depths. These depths were analysed by Michael Crum.The SAVILLE cryptographic algorithm; see note concerning Crum's career The British at Bletchley Park later also broke into Sturgeon, although they did not break it as regularly as they broke Enigma or Tunny.
|
|
WT traffic that had already been solved, by establishing what language was the cipher in, or by collating agents' code names, signatures and other magic numbers and letters as revealed by interrogation and traffic evaluation. Once these inroads were achieved they could be cryptographically exploited. A special weakness of Allied agents' ciphers that was discovered was the use of books for enciphering. Usually only a minor inroad or other clue was enough to reproduced a piece of the cipher text, and conclusions could thence be drawn as to which book was used.
|
|
Fritz Erich Fellgiebel (4 October 1886 – 4 September 1944) was a German Army general and a conspirator in the 20 July plot to assassinate Nazi dictator Adolf Hitler. In 1929, Fellgiebel became head of the () cipher bureau of the Reichswehrministerium, which would eventually become the OKW/Chi. He was a signals specialist and was instrumental in introducing a common enciphering machine, the Enigma machine. However, he was unsuccessful in promoting a single cipher agency to coordinate all operations, as was demanded by OKW/Chi and was still blocked by Joachim von Ribbentrop, Heinrich Himmler and Hermann Göring until autumn 1943.
|
|
Once he made contact with Red Army intelligence, the strict discipline under which he was held was relaxed and he was allowed visits by his wife Margaret. On 4 January 1943, Gurevich was returned Fresnes Prison in France where he began the playback operation. However, he took up so much time enciphering and deciphering the messages that he was moved back to the house on Rue des Saussaies in Paris, where he was given a cell next to Trepper. The ciphering undertaken by Gurevich was checked at first by Gestapo officer Waldemar Lentz and then later by Hans Kurfess.
|
|
The breaking of the Allied Naval Cipher was perhaps also the biggest achievement of B-Dienst. The Combined Naval Cipher No. 3, introduced on 20 January 1941, was set aside for both American and British use, for enciphering communications to and from Atlantic convoys. The USA's entry into the war increased the number of messages B-Dienst were handling, as the number of target areas rose from 136 to 237 at the end of the war. By the end of 1943, the number of intercepts were more than 3,101,831 a year, or 8,500 per day, although duplicates were common.
|
|
Japanese radio security was good; rather than cipher machines such as the Enigma machine, which the Ultra operation was able to decipher on a large scale, they used "code books and then extremely tough enciphering methods to conceal the coded text..." Japanese formation headquarters also sent far less compromising radio traffic than their German (or Allied) counterparts. Only near the end of the battle, when the Japanese signal and staff arrangements largely collapsed, did the Allies gain significant signals intelligence. Also, the Allied armies in the field had too few Japanese linguists, to translate intercepted messages and captured documents.Allen, pp.
|
|
An enciphering- deciphering knob on the left side of the machine is set to "encipher". A dial known as the indicator disk, also on the left side, is turned to the first letter in the message. This letter is encoded by turning a hand crank or power handle on the right side of the machine; at the end of the cycle, the ciphertext letter is printed onto a paper tape, the key wheels each advance one letter, and the machine is ready for entry of the next character in the message. To indicate spaces between words in the message, the letter "Z" is enciphered.
|
|
Repeating the process for the remainder of the message gives a complete ciphertext, which can then be transmitted using Morse code or another method. Since the initial key wheel setting is random, it is also necessary to send those settings to the receiving party; these may also be encrypted using a daily key or transmitted in the clear. Printed ciphertext is automatically spaced into groups of five by the M-209 for ease of readability. A letter counter on top of the machine indicated the total number of encoded letters, and could be used as a point of reference if a mistake was made in enciphering or deciphering.
|
|
The presence of the letter s enciphering the number 3 indicates the need for turning the movable disk to a new position. The letter s is then moved under the letter A. ABCDEFGILMNOPQRSTVXZ1234 Stationary disk somqihfdbacegklnprtuz&xy; Movable disk The encipherment will resume thus: _SIFARÀ Plaintext sndhsls Ciphertext The same procedure will be continued through the end of the message, using the four numbers to designate the alphabet shifts. The Alberti disk encipherment has nothing to do with Affine Shifts, Keyword shifts, Caesar shift or Vigenère ciphers. Caesar’s cipher is a simple substitution based on the sliding of a single ordinary alphabet with fixed key.
|
|
The greatest weakness in using books for enciphering lay in the fact that, once the book was compromised, an entire transmission could be solved automatically. Th weakness existed even if the book in question could not be secured in the same edition or impression. It was still possible for Referat Vauck, although after considerable research to find the right place in the book and to secure fluent deciphering systems by means of conversion tables. As a rule, the cipher discipline of Allied agents was good, with security breaches seldom committed, and if mistakes were made could usually be traced back to a weakness in the cipher system itself.
|
|
The Funkabwehr was never primarily concerned with the intelligence aspects of double-crosses, though where cooperation with the C.E. service was good, officers of the Aussenstellen were often more or less fully in the picture. Generally speaking the Funkabwehr units supervised the technical WT aspects of such cases and where Referat Vauck cryptanalysts were available at the Aussenstellen these handled the cipher details. In the Operation Nordpol case in the Netherlands, the Orpo unit was entirely responsible for transmission and enciphering although there were no cryptanalysts available. Plaintext messages were received from the Sonderführer Huntemann of Abwehr III but the actual working of the agents concerned was handled by the Orpo.
|
|
There was very little in terms of organization in Pers Z S, in April 1945, when World War II was coming to an end. Working conditions meant that all elements of the unit were working in the same general area, since the evacuation of Berlin in November 1943. However, one cardinal organization rule was followed: the rule was that mathematical cryptanalysis involving the initial solution of extremely difficult systems, the solutions of complex encipherments and additives and the application of machine systems and techniques to these problems should be kept separate from linguistic cryptanalysis. This was defined as current solutions of known additive and enciphering systems, code-book reconstruction, translation and publication.
|
|
The Enigma operator could rotate the wheels by hand to change the letter of the alphabet showing through a window, to set the start position of the rotors for enciphering a message. This three-letter sequence is the "message key". There are 26 × 26 × 26 17,576 possible positions of the set of three rotors, and hence different message keys. By opening the lid of the machine and releasing a compression bar, the set of three rotors on their spindle could be removed from the machine and their sequence (called the "wheel order" at Bletchley Park) could be altered. Multiplying 17,576 by the six possible wheel orders gives 105,456 different ways that the scrambler could be set up.
|
|
The Red machine encrypted and decrypted texts written in Latin characters (alphabetic only) for transmission through the cable services. These services charged a lower rate for texts that could be pronounced than for random strings of characters; therefore the machine produced telegraph code by enciphering the vowels separately from the consonants, so that the text remained a series of syllables. (The letter "Y" was treated as a vowel.) Per International Telegraph Union regulations at the time, pronounceable words in telegrams were charged a lower rate than unpronounceable code groups. The "sixes and twenties" effect (as American analysts referred to it) was a major weakness which the Japanese continued in the Purple system.
|
|
Fleet paymaster C. J. E. Rotter, a German expert from the naval intelligence division, was tasked with using the SKM codebook to interpret intercepted messages, most of which decoded as nonsense since initially it was not appreciated that they were also enciphered. An entry into solving the problem was found from a series of messages transmitted from the German Norddeich transmitter, which were all numbered sequentially and then re-enciphered. The cipher was broken, in fact broken twice as it was changed a few days after it was first solved, and a general procedure for interpreting the messages determined. Enciphering was by a simple table, substituting one letter with another throughout all the messages.
|
|
To decrypt a Tunny message required knowledge not only of the logical functioning of the machine, but also the start positions of each rotor for the particular message. The search was on for a process that would manipulate the ciphertext or key to produce a frequency distribution of characters that departed from the uniformity that the enciphering process aimed to achieve. While on secondment to the Research Section in July 1942, Alan Turing worked out that the XOR combination of the values of successive characters in a stream of ciphertext and key emphasised any departures from a uniform distribution. The resultant stream (symbolised by the Greek letter "delta" Δ) was called the difference because XOR is the same as modulo 2 subtraction.
|
|
The search was on for a process that would manipulate the ciphertext or key to produce a frequency distribution of characters that departed from the uniformity that the enciphering process aimed to achieve. Turing worked out that the XOR combination of the values of successive (adjacent) characters in a stream of ciphertext or key, emphasised any departures from a uniform distribution. The resultant stream was called the difference (symbolised by the Greek letter "delta" Δ) because XOR is the same as modulo 2 subtraction. So, for a stream of characters S, the difference ΔS was obtained as follows, where _underline_ indicates the succeeding character: :::: ΔS = S ⊕ _S_ The stream S may be ciphertext Z, plaintext P, key K or either of its two components \chi and \psi.
|
|
The U-570 papers included all supporting documentations for the Naval Key M ciphers. Maertens's verdict in his final report had some very worrying conclusions: > We have to accept that the U-570 might have been captured by the enemy > without anything having been destroyed. In these circumstances it cannot be > ruled out that... a large amount of cipher documents are in enemy's hands. > If this is true, the security of our enciphering procedure has been > weakened... Out cipher will have been compromised if, as well as the enemy > capturing the codebooks, our officers, who are now POW's have told the enemy > the keyword, which since June 1941 has been given verbally to the U-boat > commander so that he could alter the printed list of Enigma settings.
|
|
Roessler, and Rado's network, particularly Allan Foote, Rado's main radio operator, were prepared to work flat out to maintain the speed and flow of the information. At the peak of its operation, Rado's network was enciphering and sending several hundred messages per month, many of these from "Lucy". Meanwhile, Roessler alone had to do all the receiving, decoding and evaluating of the "Lucy" messages before passing them on; for him during this period it became a full-time operation. In the summer of 1943, the culmination of "Lucy's" success came in transmitting the details of Germany's plans for Operation Zitadelle, a planned summer offensive against the Kursk salient, which became a strategic defeat for the German army--the Battle of Kursk gave the Red Army the initiative on the eastern front for the remainder of the war.
|
|
However, acrostics may also be used as a form of steganography, where the author seeks to conceal the message rather than proclaim it. This might be achieved by making the key letters uniform in appearance with the surrounding text, or by aligning the words in such a way that the relationship between the key letters is less obvious. This is referred to as null ciphers in steganography, using the first letter of each word to form a hidden message in an otherwise innocuous text. Using letters to hide a message, as in acrostic ciphers, was popular during the Renaissance, and could employ various methods of enciphering, such as selecting other letters than initials based on a repeating pattern (equidistant letter sequences), or even concealing the message by starting at the end of the text and working backwards.
|
|
Actually the table can be compiled by heart by moving the lower list one place to the right following the alphabetic order of the index letters, firstly the vowels, then the consonants: A, E, I, O, V, C, G, M, Q, S, Y. Encipherment is performed by using an agreed-upon phrase called countersign, placed over the plaintext. With reference to the table, one substitutes the plaintext letter with the letter that is above or under it in the alphabet identified by the capital letter of the countersign. Enciphering: `VIRTVTIOMNIAPARENT VIRTVTIOMNIAPARENT VI Countersign` `larmataturchescapa rtiraacinquedilugl io Plaintext` `SYBOVEYLDANVOFSZLP IINCVPNSHMLRNXOIZN RD Ciphertext` Deciphering: `VIRTVTIOMNIAPARENT VIRTVTIOMNIAPARENT VI Countersign` `SYBOVEYLDANVOFSZLP IINCVPNSHMLRNXOIZN RD Ciphertext` `larmataturchescapa rtiraacinquedilugl io Plaintext` This cipher is a letter- by-letter polysubstitution using a long literal key string. The system is still periodic although the use of one or more long countersigns makes it sufficiently secure.
|
|
The first clue came from the British, who had noticed that the code's letters did not change randomly. If A changed to P, then elsewhere P was replaced by A. The British made no further headway, but the Poles realized that what was manifesting was Enigma's exclusivity principle that they had discovered in 1932. The Germans' carelessness meant that now the Poles, having after midnight solved Enigma's daily setting, could with no further effort also read the Luftwaffe signals. The Germans, just before opening their 10 May 1940 offensive in the west that would trample Belgium, Luxembourg and the Netherlands in order to reach the borders of France, once again changed their procedure for enciphering message keys, rendering the Zygalski sheets "completely useless" and temporarily defeating the joint British-Polish cryptologic attacks on Enigma. According to Gustave Bertrand, "It took superhuman day-and-night effort to overcome this new difficulty: on May 20, decryption resumed."Bertrand (1973) pp. 88–89 Following the capitulation of France in June 1940, the Poles were evacuated to Algeria. On October 1, 1940, they resumed work at "Cadix", near Uzès in unoccupied southern, Vichy France, under the sponsorship of Gustave Bertrand.
|
|
He was a resourceful, inventive and practical engineer. He patented an enciphering and deciphering machine,GB patent 1605232, 30-5-85 Encyphering and Decyphering Machines assigned to the Ministry of Supply with no financial benefit to himself; and he had so many ideas for civilian projects which could not be exploited within the service that he resigned his commission in 1947 in order to set up as a consulting engineer. Partly as a result of his wartime contacts, his company, Henn-Collins Associates, undertook a wide range of projects for government agencies and commercial organisations worldwide, mostly in the field of telecommunications,GB patent GB846895, 29-6-65 Electronic indicator system more particularly for use in mines but he had other interests as well, and in the 1950s and 60s he patented a number of devices of an electro-mechanical nature.US patent 2900848, 25-8-59 Mechanical selective positioning mechanismGB Patent GB807672, 25-8-59 Selective positioning mechanismsGB patent 778408, 10-7-57 Improvements in and relating to mechanical selective positioning mechanisms In his workshop he developed his idea for a quartz crystal clock which by using transistors in place of thermionic valves, made possible a much smaller quartz clock than was previously feasible.
|
|