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What is ULTRA/Enigma? A Q/A

Discussion in 'Weapons & Technology in WWII' started by chris the cheese, May 16, 2011.

  1. chris the cheese

    chris the cheese Member

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    I've noticed over the years that a lot of people confuse elements of the ULTRA/ENIGMA story, both in the press, general conversation and indeed on this board.

    So, I've come up with a few Q/As.

    Q. What was ULTRA intelligence?

    A. Ultra actually had different meanings depending on the point of time being discussed. Initially it was a form of secret classification. At the time the highest British security classification for material was 'Most Secret'. The sensitivity of the material gathered from Axis message traffic was deemed to be highly extreme, and to differentiate this material from other 'Most Secret' documents the prefix 'Ultra' was added. Thus material gathered from this source was known as 'Most Secret Ultra'. When the US entered the war the classification was altered to 'Top Secret Ultra' to match US security classification standards. As a result all high-level radio/teleprinter traffic intercepted was placed under the category of Ultra. So when people are talking about 'Ultra' that is what they are talking about.

    Q. What was Enigma?

    A. Enigma was the name of the machine cipher system designed by Arthur Scherbius and first patented in 1918. Initially the system was designed for commercial use to protect corporate wireless traffic. In 1925 the German Navy adopted the enigma system and added a number of features to make the system considerably more secure. By 1928 the German Army had also adopted a version of the system, and by the outbreak of war various versions of the system were in use, not just among the German military, but also the Abwehr, railway system, etc, it was also being widely used by other Axis powers.

    Its advantage was its relative portability combined with what was considered first-rate security.

    Q. Did the Axis powers use any other systems?

    A. Yes. A number of different systems were used, perhaps most notably the Siemens and Halske T52 and the Lorenz SZ/40 and SZ/42 machines. These were teleprinter cipher systems. They were also far more secure than Enigma. Their drawback was a lack of portability. As a result they tended to be used further up the chain of command, namely the German High Command to Generals.

    Q. What is Bletchley Park?

    A. Bletchley Park is a small estate in Buckinghamshire, some 40 miles North of London. Shortly prior to the outbreak of the war it was purchased on the behalf of the Government Code and Cypher School (GC&CS) and the Secret Intelligence Service (SIS, often known as MI6) by Admiral Hugh Sinclair the then head of SIS. Bletchley Park was to serve to house both GC&CS and SIS when they were evacuated from London on the outbreak of the war. However, Bletchley Park served only as the primary war station and head quarters of GC&CS, numerous out stations and offices were maintained in relatively nearby locations.

    Q. What was GC&CS?

    A. As noted GC&CS stood for the Government Code and Cypher School, which was formed in 1919 as an amalgamation of the Army and Royal Navy's cryptanalysis departments. GC&CS had two main roles. Firstly, and ostensibly, it existed to provide advice and training to British state institutions/services in maintaining secure communications. Secondly, and more famously, it served as a centralised cryptanalysis institution for the British state. Following the war it was re-dubbed the Government Communications Headquarters (GCHQ) and moved to Cheltenham.

    Q. What was a Bombe machine?

    A. Named after the Polish machine bomba, which had been used with some success in breaking into Enigma traffic, it was a machine designed by Alan Turing and improved by Gordon Welchman to aid British cryptanalysts in reading Enigma traffic. The machine did not actually break the cipher, rather it was a labour saving device which removed possibilities.

    Q. What was a Colossus Computer?

    A. The Colossus Computers were electro-mechanical machines (some debate exists as to whether they were true computers as we understand the term today) designed to aid cryptanalysts read messages enciphered by Lorenz SZ/40 and SZ/42 machines. It was designed by a team headed by Tommy Flowers (a post office engineer), and contrary to popular belief was not designed by Alan Turing.

    Q. What were Purple and Magic?

    A. In 1939 Germany provided Japan with a modified Enigma system. The traffic emerging from this system was dubbed by American cryptanalysts as 'Purple'. The name derives from the two code names given to the previous Japanese systems, which were Red and Blue. Both systems proved readable, the new system on the other hand was not. The new system was dubbed purple (a mixture of the two other colours used previously). Magic was the code name for the combined US cryptanalysis project during the Second World War.

    Q. The US and Britain were reading Purple traffic before the attack on Pearl Harbour, does that mean that they had prior knowledge of the attack?

    A. No. Purple was confined to Japanese diplomatic traffic. The Japanese military services employed different systems. At the highest level the Navy employed a system known as JN-25. JN-25 was regularly changed and improved making the process of reading traffic much harder. For example, by late 1940 in-roads were beginning to be made and a tiny fraction of traffic was beginning to be read. Then on August 1, 1941 the Japanese introduced a new 50,000-group list of additives which set the cryptanalysts back to the drawing board to start over.
     
  2. TacticalTank

    TacticalTank Member

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    Well, from what I know from U-571, the enigma was the German radio communication code. The code was being changed constantly and if the code is known, you may listen in on all German radio communication from what I've seen in this movie.

    Hope this helped and if im wrong please tell me.
     
  3. chris the cheese

    chris the cheese Member

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    Well, basically a radio bloke would be tapping out the message given to him each letter at a time. What they did with the Enigma machine was put the message through that first then send it once it had been enciphered. That way you wouldn't be sending your messages plain text. The way the enigma system worked is that there were lots (and lots and lots) of different ways the machine could be set up. Each different set up would create a different outcome. In other words, if you change the settings then your message will read differently. They changed the settings every day to a pre-arranged set up.That way even if your opponent worked out the daily set up it wouldn't matter because the next day would be completely different and they would be back to square one.

    In regards to all the German traffic, that isn't quite right either. You could listen in to all the German traffic using that particular set up and that particular Enigma system. The various arms of the German military structure all used different systems, so even if, say, you were reading the Naval Enigma that did not imply that you could read what the Luftwaffe was sending.
     
  4. CPL Punishment

    CPL Punishment Member

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    The function of the "Bombe" machines was to sort candidate solutions by probability. This was done by examining letter groupings. For example, since the plaintext language was assumed to be German a candidate decrypt containing the group UNG, a common sequence in German, would be considered probable, that is, on the right track, whereas a decrypt containing PQD would be considered improbable. This kind of likely/unlikely sorting is common to any cryptanalytic effort. The Bombes automated the lowest order analysis thus freeing human time and resources for more complex tasks.

    I was amused by the reference to U-571, one of the worst movies on the subject of ULTRA and WWII generally. In 2001 a much better film on the subject was released titled, appropriately enough, Enigma. A major plot point revolves around the problem the Bombes were designed to address. Two cryptanalysts are working on a message using a captured Enigma machine. They configure the machine using the rotor and plug board setting they believe are correct but the decrypt begins producing unlikely groups such as CZW. Assuming the plaintext is German they conclude the setting are wrong, but then they realize their assumptions about the plaintext are wrong. I won't go any further because it would be a spoiler. Note to TacticalTank burn that U-571 DVD and get Enigma.
     
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  5. chris the cheese

    chris the cheese Member

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    Thanks for filling in those details. I deliberately avoid trying to explain the technical aspects of the topic because I find that they often defy easy description. It is nice to read a person who clearly can make the complex easy to grasp.

    Incidentally, what is your own interest in the topic?
     
  6. Takao

    Takao Ace

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    just to nitpick,
    The highest level of Japanese naval codes was the "Admirals' Code." It was very cumbersome to encrypt, decypher and coupled with it's importance, it was not often used. JN-25, was the Navy's "operational" code, which they used for almost everything else.
     
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  7. chris the cheese

    chris the cheese Member

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    As I understand it, by 1941 the system was pretty much unused (That said, I also vaguely recall reading a few years ago that despite this a fair amount of resources and expertese were needlessly expended on it). Indeed, I'd forgotten about it. Now that you reminded me of I had a look in a couple of books to hand to get a better idea and could find no trace in the index, but given the scope of the books that doesn't necessarily mean a lot. If you know more or know of a good book I would be glad to hear of it.
     
  8. Takao

    Takao Ace

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    "Combined Fleet Decoded" by John Prados, pub. 1995 by the Naval Institute Press.

    provides excellent coverage of the US intelligence & codebreaking efforts against Japan.

    AFAIK, it is out-of-print, but a used copy should be easily found.
     
  9. Involute

    Involute recruit

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    Newbie here. I was under the impression (having read as much somewhere) that the main reason the Bombes were successful in decrypting Enigma messages, or at least prioritizing keys for their decryption, was that, except for the Navy, the German military services were very sloppy in their key-management: they didn't change the keys often and used proper names, dates, and other "easily" guessed info instead of random characters, significantly constraining the universe of keys to be searched by the Bombes (the Navy's discipline, on the other hand, lead to much fewer Naval decryptions than for the other services). If this is so, however, it implies the key management authority was sloppy, rather than the Enigma operators who would have been issued their keys by the authority. I.e., it's easy to understand a German "grunt" using his girlfriend's name as a key, but then whoever he was transmitting to wouldn't know that, since they'd both have to use the same key and (in the pre-public key days of WWII) there'd be no way to send it. On the other hand, it's hard to fathom a central authority, especially a German one, being so lax. Was that really the case, or am I completely off-base with my initial impression?
     
  10. brndirt1

    brndirt1 Saddle Tramp

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    I have read that the "protocol" that many times gave the boys at Bletchely Park a leg up was using the same name over and over. That meant that no matter what the new key was, there was a clue in the transmission. A favorite sign-off was quite often Heil Hitler, now if that shows up at the end of every transmission, it is a link to the new settings.
     
  11. urqh

    urqh Tea drinking surrender monkey

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    And no discussion on Enigma should pass by without the mention of Gubbins...and his part in the British military mission to Poland 1939. Gubbins of British Auxilleries fame was instrumental in Britain getting that foothold...A good reference for anyones library...The Secret Wireless War
     
  12. urqh

    urqh Tea drinking surrender monkey

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    Sorry..Author...Geoffrey Pidgeon. As an aside Hanslope Park was my last posting a few years back.
     
  13. Artem

    Artem Member

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    i think there's an iTunes lectures on the enigma and how it was decrypted. Alan Turin was a bloody genius.
     
  14. urqh

    urqh Tea drinking surrender monkey

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    A bloody hard done by genius at that. Poor sod.
     
  15. Danny 21

    Danny 21 New Member

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  16. Danny 21

    Danny 21 New Member

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    With so many thousands of units ,regiments,divisions,,,organisations,,,,how did Bletchley Park decide who to concentrate on??
     
  17. Carronade

    Carronade Ace Patron  

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    There were indications from code reading and other information like ship movements that something was about to happen, but nothing specific. It was considered most likely that the Japanese would launch offensives in the Far East, likely including the Philippines - which indeed was their basic strategy; the Pearl Harbor attack was intended to prevent the US Pacific Fleet from intervening before they could complete their conquests.

    The one clue that pointed to Hawaii was the fourteen-part message which the Japanese embassy was instructed to present at 1.30 p.m. Washington time, 7.30 a.m. in Hawaii. This prompted a warning message to all of our commanders in the Pacific which mentioned the time but said we did not know what it might signify. This was the message which was delayed by atmospheric conditions and only reached Admiral Kimmel while the attack was underway.
     
    Last edited: May 7, 2018

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