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No other changes were made, which eased the changeover. Since there were only three pawls, the fourth rotor never stepped, but could be manually set into one of 26 possible positions. It allowed field configuration of notches in all 26 positions. If the number of notches was a relative prime of 26 and the number of notches were different for each wheel, the stepping would be more unpredictable.
Like the Umkehrwalze-D it also allowed the internal wiring to be reconfigured. The current entry wheel Eintrittswalze in German , or entry stator , connects the plugboard to the rotor assembly. If the plugboard is not present, the entry wheel instead connects the keyboard and lampboard to the rotor assembly. While the exact wiring used is of comparatively little importance to security, it proved an obstacle to Rejewski's progress during his study of the rotor wirings.
It took inspired guesswork for Rejewski to penetrate the modification. With the exception of models A and B , the last rotor came before a 'reflector' German: Umkehrwalze , meaning 'reversal rotor' , a patented feature unique to Enigma among the period's various rotor machines.
The reflector connected outputs of the last rotor in pairs, redirecting current back through the rotors by a different route. The reflector ensured that Enigma would be self-reciprocal ; thus, with two identically configured machines, a message could be encrypted on one and decrypted on the other, without the need for a bulky mechanism to switch between encryption and decryption modes.
The reflector allowed a more compact design, but it also gave Enigma the property that no letter ever encrypted to itself.
This was a severe cryptological flaw that was subsequently exploited by codebreakers. In Model 'C', the reflector could be inserted in one of two different positions. In Model 'D', the reflector could be set in 26 possible positions, although it did not move during encryption. In the Abwehr Enigma, the reflector stepped during encryption in a manner similar to the other wheels. In the German Army and Air Force Enigma, the reflector was fixed and did not rotate; there were four versions.
The original version was marked 'A', and was replaced by Umkehrwalze B on 1 November A third version, Umkehrwalze C was used briefly in , possibly by mistake, and was solved by Hut 6. The plugboard Steckerbrett in German permitted variable wiring that could be reconfigured by the operator visible on the front panel of Figure 1; some of the patch cords can be seen in the lid.
It was introduced on German Army versions in , and was soon adopted by the Reichsmarine German Navy. The plugboard contributed more cryptographic strength than an extra rotor. Enigma without a plugboard known as unsteckered Enigma could be solved relatively straightforwardly using hand methods; these techniques were generally defeated by the plugboard, driving Allied cryptanalysts to develop special machines to solve it. A cable placed onto the plugboard connected letters in pairs; for example, E and Q might be a steckered pair.
The effect was to swap those letters before and after the main rotor scrambling unit. For example, when an operator pressed E , the signal was diverted to Q before entering the rotors. Up to 13 steckered pairs might be used at one time, although only 10 were normally used. Current flowed from the keyboard through the plugboard, and proceeded to the entry-rotor or Eintrittswalze. Each letter on the plugboard had two jacks.
Inserting a plug disconnected the upper jack from the keyboard and the lower jack to the entry-rotor of that letter. The plug at the other end of the crosswired cable was inserted into another letter's jacks, thus switching the connections of the two letters.
Other features made various Enigma machines more secure or more convenient. Some M4 Enigmas used the Schreibmax , a small printer that could print the 26 letters on a narrow paper ribbon.
This eliminated the need for a second operator to read the lamps and transcribe the letters. The Schreibmax was placed on top of the Enigma machine and was connected to the lamp panel. To install the printer, the lamp cover and light bulbs had to be removed.
It improved both convenience and operational security; the printer could be installed remotely such that the signal officer operating the machine no longer had to see the decrypted plaintext.
For machines equipped with the extra panel, the wooden case of the Enigma was wider and could store the extra panel. A lamp panel version could be connected afterwards, but that required, as with the Schreibmax , that the lamp panel and light bulbs be removed.
In , the Luftwaffe introduced a plugboard switch, called the Uhr clock , a small box containing a switch with 40 positions. It replaced the standard plugs. After connecting the plugs, as determined in the daily key sheet, the operator turned the switch into one of the 40 positions, each producing a different combination of plug wiring.
Most of these plug connections were, unlike the default plugs, not pair-wise. The Enigma transformation for each letter can be specified mathematically as a product of permutations. Then the encryption E can be expressed as.
After each key press, the rotors turn, changing the transformation. For example, if the right-hand rotor R is rotated n positions, the transformation becomes.
Similarly, the middle and left-hand rotors can be represented as j and k rotations of M and L. The encryption transformation can then be described as. Combining three rotors from a set of five, each of the 3 rotor settings with 26 positions, and the plugboard with ten pairs of letters connected, the military Enigma has ,,,,,, different settings nearly quintillion or about 67 bits.
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. The action of pressing a key also moved one or more rotors so that the next key press used a different electrical pathway, and thus a different substitution would occur even if the same plaintext letter were entered again. For each key press there was rotation of at least the right hand rotor and less often the other two, resulting in a different substitution alphabet being used for every letter in the message.
This process continued until the message was completed. The cyphertext recorded by the second operator would then be transmitted, usually by radio in Morse code , to an operator of another Enigma machine. 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. In use, the Enigma required a list of daily key settings and auxiliary documents.
In German military practice, communications were divided into separate networks, each using different settings. These communication nets were termed keys at Bletchley Park , and were assigned code names , such as Red , Chaffinch , and Shark. Each unit operating in a network was given the same settings list for its Enigma, valid for a period of time. The procedures for German Naval Enigma were more elaborate and more secure than those in other services and employed auxiliary codebooks.
Navy codebooks were printed in red, water-soluble ink on pink paper so that they could easily be destroyed if they were endangered or if the vessel was sunk. For a message to be correctly encrypted and decrypted, both sender and receiver had to configure their Enigma in the same way; rotor selection and order, ring positions, plugboard connections and starting rotor positions must be identical.
Except for the starting positions, these settings were established beforehand, distributed in key lists and changed daily. For example, the settings for the 18th day of the month in the German Luftwaffe Enigma key list number see image were as follows:. Enigma was designed to be secure even if the rotor wiring was known to an opponent, although in practice considerable effort protected the wiring configuration.
Most of the key was kept constant for a set time period, typically a day. A different initial rotor position was used for each message, a concept similar to an initialisation vector in modern cryptography.
The reason is that encrypting many messages with identical or near-identical settings termed in cryptanalysis as being in depth , would enable an attack using a statistical procedure such as Friedman's Index of coincidence. The exact method used was termed the indicator procedure. Design weakness and operator sloppiness in these indicator procedures were two of the main weaknesses that made cracking Enigma possible.
One of the earliest indicator procedures for the Enigma was cryptographically flawed and allowed Polish cryptanalysts to make the initial breaks into the plugboard Enigma. The procedure had the operator set his machine in accordance with the secret settings that all operators on the net shared. The settings included an initial position for the rotors the Grundstellung , say, AOH. The operator turned his rotors until AOH was visible through the rotor windows.
At that point, the operator chose his own arbitrary starting position for the message he would send. An operator might select EIN , and that became the message setting for that encryption session.
This was then transmitted, at which point the operator would turn the rotors to his message settings, EIN in this example, and then type the plaintext of the message. In this example, EINEIN emerged on the lamps, so the operator would learn the message setting that the sender used to encrypt this message.
The receiving operator would set his rotors to EIN , type in the rest of the ciphertext, and get the deciphered message. This indicator scheme had two weaknesses. First, the use of a global initial position Grundstellung meant all message keys used the same polyalphabetic substitution.
In later indicator procedures, the operator selected his initial position for encrypting the indicator and sent that initial position in the clear. The second problem was the repetition of the indicator, which was a serious security flaw.
The message setting was encoded twice, resulting in a relation between first and fourth, second and fifth, and third and sixth character. These security flaws enabled the Polish Cipher Bureau to break into the pre-war Enigma system as early as The early indicator procedure was subsequently described by German cryptanalysts as the "faulty indicator technique".
During World War II, codebooks were only used each day to set up the rotors, their ring settings and the plugboard. For each message, the operator selected a random start position, let's say WZA , and a random message key, perhaps SXT.
Assume the result was UHL. He then set up the message key, SXT , as the start position and encrypted the message. Next, he used this SXT message setting as the start position to decrypt the message. This way, each ground setting was different and the new procedure avoided the security flaw of double encoded message settings. This procedure was used by Wehrmacht and Luftwaffe only.
The Kriegsmarine procedures on sending messages with the Enigma were far more complex and elaborate. Prior to encryption the message was encoded using the Kurzsignalheft code book.
The Kurzsignalheft contained tables to convert sentences into four-letter groups. A great many choices were included, for example, logistic matters such as refuelling and rendezvous with supply ships, positions and grid lists, harbour names, countries, weapons, weather conditions, enemy positions and ships, date and time tables. The Army Enigma machine used only the 26 alphabet characters. Punctuation was replaced with rare character combinations. A space was omitted or replaced with an X.
The X was generally used as full-stop. Some punctuation marks were different in other parts of the armed forces. The Kriegsmarine replaced the comma with Y and the question mark with UD. The Kriegsmarine , using the four rotor Enigma, had four-character groups.
Frequently used names or words were varied as much as possible. To make cryptanalysis harder, messages were limited to characters. Longer messages were divided into several parts, each using a different message key.
The character substitutions by the Enigma machine as a whole can be expressed as a string of letters with each position occupied by the character that will replace the character at the corresponding position in the alphabet. Since the operation of an Enigma machine encoding a message is a series of such configurations, each associated with a single character being encoded, a sequence of such representations can be used to represent the operation of the machine as it encodes a message.
The character mappings for a given configuration of the machine are in turn the result of a series of such mappings applied by each pass through a component of the machine: the encoding of a character resulting from the application of a given component's mapping serves as the input to the mapping of the subsequent component.
For example, the 4th step in the encoding above can be expanded to show each of these stages using the same representation of mappings and highlighting for the encoded character:.
Here the encoding begins trivially with the first "mapping" representing the keyboard which has no effect , followed by the plugboard, configured as AE. The Enigma family included multiple designs.
The earliest were commercial models dating from the early s. Starting in the mids, the German military began to use Enigma, making a number of security-related changes. Various nations either adopted or adapted the design for their own cipher machines. An estimated , Enigma machines were constructed. After the end of World War II, the Allies sold captured Enigma machines, still widely considered secure, to developing countries.
On 23 February , [ failed verification ] Arthur Scherbius applied for a patent for a ciphering machine that used rotors. They approached the German Navy and Foreign Office with their design, but neither agency was interested. Chiffriermaschinen AG began advertising a rotor machine, Enigma model A , which was exhibited at the Congress of the International Postal Union in The machine was heavy and bulky, incorporating a typewriter.
In Enigma model B was introduced, and was of a similar construction. This method of output was much more reliable and cost effective. The Enigma C quickly gave way to Enigma D In Hugh Foss at the British Government Code and Cypher School was able to show that commercial Enigma machines could be broken, provided suitable cribs were available.
Other countries used Enigma machines. The Spanish also used commercial Enigma machines during their Civil War. British codebreakers succeeded in breaking these machines, which lacked a plugboard. In the Polish Cipher Bureau detected that it was in use for high-level military communication, but it was soon withdrawn, as it was unreliable and jammed frequently. An Enigma T model, code-named Tirpitz , was used by Japan. Once the British figured out Enigma's principle of operation, they fixed the problem with it and created their own, the Typex , which the Germans believed to be unsolvable.
The Reichsmarine was the first military branch to adopt Enigma. This Enigma variant was a four-wheel unsteckered machine with multiple notches on the rotors. Enigma machine G was modified to the Enigma I by June The major difference between Enigma I German Army version from , and commercial Enigma models was the addition of a plugboard to swap pairs of letters, greatly increasing cryptographic strength. Other differences included the use of a fixed reflector and the relocation of the stepping notches from the rotor body to the movable letter rings.
By , the Reichswehr had suggested that the Navy adopt their machine, citing the benefits of increased security with the plugboard and easier interservice communications. While the Army used only three rotors at that time, the Navy specified a choice of three from a possible five. In December , the Army issued two extra rotors so that the three rotors were chosen from a set of five. A four-rotor Enigma was introduced by the Navy for U-boat traffic on 1 February , called M4 the network was known as Triton , or Shark to the Allies.
The extra rotor was fitted in the same space by splitting the reflector into a combination of a thin reflector and a thin fourth rotor. Enigma G, used by the Abwehr , had four rotors, no plugboard, and multiple notches on the rotors. It had locally re-wired rotors and an additional lamp panel.
The effort to break the Enigma was not disclosed until the s. Since then, interest in the Enigma machine has grown. Enigmas are on public display in museums around the world, and several are in the hands of private collectors and computer history enthusiasts.
The Deutsches Museum in Munich has both the three- and four-rotor German military variants, as well as several civilian versions.
This machine is on loan from Australia. The International Museum of World War II near Boston has seven Enigma machines on display, including a U-Boat four-rotor model, one of three surviving examples of an Enigma machine with a printer, one of fewer than ten surviving ten-rotor code machines, an example blown up by a retreating German Army unit, and two three-rotor Enigmas that visitors can operate to encode and decode messages. Computer Museum of America in Roswell, Georgia has a three-rotor model with two additional rotors.
The machine is fully restored and CMoA has the original paperwork for the purchase on 7 March by the German Army. Replicas are available in various forms, including an exact reconstructed copy of the Naval M4 model, an Enigma implemented in electronics Enigma-E , various simulators and paper-and-scissors analogues. In early October , Bletchley Park officials announced that they would pay the ransom, but the stated deadline passed with no word from the blackmailer.
Shortly afterward, the machine was sent anonymously to BBC journalist Jeremy Paxman , missing three rotors. In November , an antiques dealer named Dennis Yates was arrested after telephoning The Sunday Times to arrange the return of the missing parts. The Enigma machine was returned to Bletchley Park after the incident.
In October , Yates was sentenced to ten months in prison and served three months. These four-rotor commercial machines had helped Franco's Nationalists win the Spanish Civil War , because, though the British cryptologist Alfred Dilwyn Knox in broke the cipher generated by Franco's Enigma machines, this was not disclosed to the Republicans, who failed to break the cipher. The Nationalist government continued using its 50 Enigmas into the s. The Enigma was influential in the field of cipher machine design, spinning off other rotor machines.
The British Typex was originally derived from the Enigma patents; Typex even includes features from the patent descriptions that were omitted from the actual Enigma machine. The British paid no royalties for the use of the patents, to protect secrecy. The Typex implementation is not the same as that found in German or other Axis versions. Little used, it contained four rotors mounted vertically. In the United States, cryptologist William Friedman designed the M , a machine logically similar, although not in construction.
A unique rotor machine was constructed in by Netherlands-based Tatjana van Vark. This device makes use of point rotors, allowing letters, numbers and some punctuation to be used; each rotor contains parts.
Several software implementations exist, but not all exactly match Enigma behaviour. The most commonly used software derivative that is not compliant with any hardware implementation of the Enigma is at EnigmaCo. Many Java applet Enigmas only accept single letter entry, complicating use even if the applet is Enigma compliant. Technically, Enigma home is the largest scale deployment of a software Enigma, but the decoding software does not implement encipherment making it a derivative as all original machines could cipher and decipher.
A user-friendly three-rotor simulator, where users can select rotors, use the plugboard and define new settings for the rotors and reflectors is available. The "very fast" option produces 26 characters in less than one second. From Wikipedia, the free encyclopedia.
German cipher machine. This article is about the Enigma machine itself. For the Allied cracking of the machine, see Cryptanalysis of the Enigma. Main article: Cryptanalysis of the Enigma. Main article: Enigma rotor details. Play media.
This section possibly contains original research. Please improve it by verifying the claims made and adding inline citations.
Statements consisting only of original research should be removed. April Learn how and when to remove this template message. Electronic implementation of an Enigma machine, sold at the Bletchley Park souvenir shop. This section appears to contain trivial, minor, or unrelated references to popular culture.
Please reorganize this content to explain the subject's impact on popular culture, providing citations to reliable, secondary sources , rather than simply listing appearances. Unsourced material may be challenged and removed. July Retrieved 16 December Intelligence in Warfare. New York: Alfred A. Knopf Doubleday Publishing Group.
ISBN Crypto Museum. Retrieved 1 December Retrieved 31 May Spartacus Educational. Rose-Hulman Institute of Technology. Ultra also encompassed decrypts of the German Lorenz SZ 40 and 42 machines that were used by the German High Command, and decrypts of Hagelin ciphers and other Italian ciphers and codes, as well as of Japanese ciphers and codes such as Purple and JN Archived from the original zip on 19 July Technical Specification of the Enigma.
Retrieved 15 November Retrieved 17 July A boat is best stored under cover or in an enclosed space like a garage or storage unit with the cover off and hatches open to allow water to evaporate.
Routinely check around mounts and fittings attached to the wood. Pay particular attention to any screws in the deck. It is good to apply sealant every few years to these areas to keep out the water. Related to wood rot is a problem with drainage. Reports indicate that some models do not have adequate drainage away from wooden decks and hatches, leading to mold and rot if the wood is not sealed properly. Some areas have spray foam under the decking, which can trap water between the decking and the bilge area and lead to problems.
One solution is to use a funnel that will reach past the vent opening, allowing fuel to enter at full speed. Otherwise, you may have to add fuel slowly when filling the tank.
This is not an issue on all models. Others have said that water scooping over the bow is a problem. In either case, rough water exacerbates the issue. While some of this may be driver related, the reports on different forums indicate that some models have a problem. This might not cause concern in warmer climates, but if you venture out in winter or live in a colder area, being splashed constantly is a real drag.
Some models of Crestliners, in particular smaller ones, have poorly thought out use of space, leading to issues with storage for gear and batteries. Crestliner boats have a long history and a good reputation, but there have been issues over the years. Some boaters are fiercely loyal to the Crestliner brand, while some vow to never buy one. Unfortunately, every brand has unsatisfied customers, but if you arm yourself with knowledge and know what to look out for, you can avoid the problematic models.
Skip to content Crestliner boats are wildly popular in the freshwater world. In this article, we will explore some problems reported by owners. These are the most commonly reported problems with Crestliners: Table of Contents. Was this article helpful? Click to share Did you find wrong information or was something missing?
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