Catch up on stories from the past week (and beyond) at the Slashdot story archive


Forgot your password?

Help Break Original Enigma Messages 272

Stereo writes "The Enigma Machine was cracked in Poland in 1932, but three messages remain unbroken, despite having been intercepted in the North Atlantic in 1942. The M4 Project, named after the four rotor Enigma M4 used for encryption, is a distributed computing effort to break them. One message has already been deciphered successfully!"
This discussion has been archived. No new comments can be posted.

Help Break Original Enigma Messages

Comments Filter:
  • by Derling Whirvish ( 636322 ) on Sunday February 26, 2006 @02:56AM (#14802977) Journal
    There are more than just those three message still unbroken. Those were just three that were selected for this project.
    • Besides, what is left to prove for this M4 project?

      The original breakthrough was the deed of one brilliant mind, the Polish matematician Marian Rejewski, and he was helped (however little) by the fact that Hans-Thilo Schmidt sold the Enigma plans to the French secret services.

      The English project was a joint effort of many more minds and succeeded because the Germans did all kinds of mistakes which reduced the scope of the searches. Even so, the encryptions used by the German Navy back then (which didn't ma
  • Error (Score:4, Interesting)

    by c0dedude ( 587568 ) on Sunday February 26, 2006 @02:57AM (#14802981)
    Are they sure they're not just bad data? Wouldn't it be a good idea to send crap through the lines every so often to throw people off the trail?
    • But then wouldn't that confuse the actual recipient as well?
      • It's normal to tell the receiver when the next message will be likely to arrive, or even have a scheduled receive time every week.
    • Re:Error (Score:5, Interesting)

      by Anonymous Coward on Sunday February 26, 2006 @03:22AM (#14803024)
      One of the main reasons the Enigma crypts were breakable with 1940's technology is that the Germans did _not_ do useful things like that. They re-used keys, left cribs in the messages, etc.

      Basically, they put too much faith in the encryption technology, and didn't put enough effort into securing the rest of the process. It's not unusual, many of today's systems have similar issues.

      The comments in Bruce Schneier's blog [] list some more things that went wrong in the Enigma process.

      • Enigma's major weakness, besides the operator's habits, was it's inability to encode the source letter with the same letter. Enigma was mechanically unable to encode a letter with the same letter. Pushing "A" will never ever get you an "A" on the output. This allowed them to check for strings, like ranks and names as the letters in the string will not appear in the encode.
    • Correct, a really good crypto system would be continuously transmitting a constant stream of jibberish and would have a preshared library of start and stop keywords to allow good data to be picked out by automatic means. This would allow a strong cryptographic system to also be resistant to traffic analysis. However the German enigma setup was anything but good.
      • Correct, a really good crypto system would be continuously transmitting a constant stream of jibberish and would have a preshared library of start and stop keywords to allow good data to be picked out by automatic means.

        Kind of looks like Waste to me.

      • Re:Error (Score:2, Informative)

        "If I take a letter, lock it in a safe, hide the safe somewhere in New York, then tell you to read the letter, that's not security. Thats obscurity. On the other hand, if I take a letter and lock it in a safe, and give you the safe along with the design specifications of the safe and a hundred identical safes with their combinations so that you and the worlds best safecrackers can study the locking mechanism - and you still can't open the safe and read the letter - thats security." Applied Cryptography, Bru
        • That's kind of a bold statement -- care to elaborate?

          The design of an encryption system itself -- as in the algorithm or device used for encipherment -- doesn't make it more or less resistant to traffic analysis. You could be using one-time pads, essentially unbreakable encryption, and still be vunerable to traffic analysis if you were using it poorly.
    • Re:Error (Score:3, Interesting)

      by massivefoot ( 922746 )
      The Germans were over-confident to the point of incompetence with their encryption. The British certainly didn't attempt to change this, and ULTRA [] was only declassified in 1974, and it's likely as not that the Germans still thought their ciphers invincible at the end of the war.
      • That's in large part because a big chunk of Europe also belived it -- and used Enigma machines to encrypt diplomatic traffic well into the 1960s.

        We declasified the break because the machines went out of service.
    • Modern military backhaul systems are always transmitting - they never stop. When they are not sending useful data, they send random data.
    • Who said it had to be intentional?
      Maybe someone's cat walked across the keyboard or someone sat on the keyboard or the operator was drunk and forgot how to type or someone set it wrong and sent a useless message, shortly being transfered to the Russian front.
      Well we won't know until these are cracked. What!? no Win2k version, D'oh, must use XP instructions.
    • Are they sure they're not just bad data?

      Reminds me of when somebody showed me what looked like a magic eye [] picture, but wasn't. I'm usually pretty good at getting my eyes focused just right to see the picture, but I was working on this one for 5 minutes before the joker started sniggering.

      Scary thing, I was just about seeing something!

  • This just goes to show the power of properly implemented encryption.
    • by neoform ( 551705 ) <> on Sunday February 26, 2006 @03:00AM (#14802989) Homepage
      So what if it took 60 years to crack, those subs are sitting ducks now! Good encryption my ass..
    • Please tell me you're joking? properly implemented encryption? It was terrible, most likely MMaestro is right, there was no simply pressing need to decrypt them. If you want to know why the encryption wasn't properly implemented, I'd recommend ULTRA [], or The Code Book by Simon Singh.
      • Please tell me you're joking? properly implemented encryption? It was terrible

        Actually, the Germans' use of the Enigma was the most terrible part. Operators using their initials as keys, sending messages that were identical (or nearly so, such as form letters) using different keys, sending messages that consisted of nothing but the same letter, etc etc etc.

        Enigma had its share of design problems, don't get me wrong. But I would hardly call it terrible, especially given the age of the technology. It
      • It is in fact true that the number one flaw of the encryption was its implementation, but lets consider the one message that this project has decrypted. The post-1939 engima encryption, at its greatest strength had 23,276,989,683,567,292,244,023,724,793,447,227,62 8 ,130,289,261,173,376,992,586,381,072,041,865,764,8 82,821,864,156,921,211,571,619,366,980,734,115, 647,633,344,328,661,729,280,000,000,000,000,000 possible configurations, roughly 2×10^145. Which, you must consider that there is roughly 10^8
  • Okay, is this just one big conspiracy or not? I have *NEVER* had a Coral Cache link work. Not once.

    I think you're all just messing with my head. /me reaches for tin foil hat

    • It has worked for me in the past, but it does seem sloooow today. So maybe they're turning against me too '-)
    • Okay, is this just one big conspiracy or not? I have *NEVER* had a Coral Cache link work. Not once.

      You said it. I'm glad I'm not the only one.

      It looks to me like Corel Cache can be Slashdotted as well. Indeed, the only time I ever find that Corel Cache helps me to read a story that /. links to is when someone submits the Corel Cache link, and I can then go to the original story that is supposed to be cached, because the rest of /. is hammering Corel Cache instead.

      Corel Cache doesn't have a special "B

    • Me neither. Meanwhile, the original link is working just fine.
    • I know it's Sunday, but if you're browsing from work or school you need to keep in mind that some places don't allow you to make any connections to port 8090.
  • by Derling Whirvish ( 636322 ) on Sunday February 26, 2006 @02:59AM (#14802987) Journal
    Here's a site where you can order a parts kit to build you own [] Enigma Machine.
  • by Derling Whirvish ( 636322 ) on Sunday February 26, 2006 @03:02AM (#14802992) Journal
    Here's a Java Enigma Simulator [].
  • Why are there still these 3 messages that are unbroken? None of TFA seems to talk about this. Even though it is interesting to note that it's estimated to take 1-10 days of 100 celerons 24/7 to crack a ciphertext of 180 letters long. And that's with computers that are 60 years ahead of the technology that the enigma was made from.
    • If it wasn't for the Enigma machine it is unlikely computers would be as advanced as they are today since cracking the enigma code was THE reason computer development really got started with the Mark I in WWII.
      • If it wasn't for the Enigma machine it is unlikely computers would be as advanced as they are today since cracking the enigma code was THE reason computer development really got started with the Mark I in WWII.

        This is just not true. Enigma was broken using "bombes" which were not computers by any reasonable definition of the term. A bombe was simply an electromechanical device that tested each possible rotor setting. Colossus, OTOH, considered by some to be the first programmable digital computer, was

        • by igb ( 28052 ) on Sunday February 26, 2006 @06:55AM (#14803415)
          Although Colossus was classified, a lot of the people who worked on it went on to become the initial wave of computer builders in UK universities after the war. It's also reputed that at least one Colossus survived at Cheltenham into the 1970s, presumably working on multi-wheel stream ciphers.


    • Enigma wasn't cracked because of weaknesses in the algorithm(although those do exist), it was broken because of the German's sloppy cryptography practices and the fact that the allies found out what process they were using to determine their keys.

      If a cop is wearing body armor, it doesn't mean that he can walk out into a torrent of incoming bullets. Chances are that one of those bullets will find a weakness in his armor, or simply strike him in a place where he's not protected. Similar principle here.

    • by jd ( 1658 ) <> on Sunday February 26, 2006 @03:58AM (#14803099) Homepage Journal
      The Enigma code was broken only in the trivial sense that it was possible to brute-force decrypt the messages, once the algorithm, prng and seed value were known. It was not "broken" in the purist sense of the term, in that there is no shorter method of cracking the messages other than by brute-force.

      The full Enigma code is extremely difficult to break. The machine used by Alan Turing (Colossus) was massively parallel and highly optimized for the task - so much so that it is actually able to compute something like ten times as many keys per second as a modern Pentium 4 using the same algorithm. Not bad, for a machine of that era.

      The Enigma suffered from numerous weaknesses - almost all of them operator error. The encryption mechanism itself was damn good and, if used correctly each time, every time, it would have been horribly difficult for the Bletchley Park team to break.

      The one event that turned Enigma transparent was the re-transmission of a message without the cogs being randomized first. Because a machine had already been recovered, Turing knew what the cogs were, just not where they should be in relation to each other. By having the same message sent twice without change and without a prior reset, it was possible to overlay the two messages and thereby infer virtually everything else.

      This only allows you to crack messages which use the same prng for initialization and identical cogs. Since the cogs were designed to be swappable, non-standard configurations would have been possible. These would not have been crackable - and would likely not be crackable today, if non-standard enough. (The number of arrangements you would need to test increases with the factorial of the number of ways the cogs could be designed, as well as the factorial of the number of ways the cogs could be inserted into the machine.)

      The possibility exists that certain units may have used non-standard Enigma codes, but if that is the case, those codes will NOT be broken by this effort. The groups that spirited high-ranking Germans to South America and other "secure" locations must have had a communication system that the Allies had not yet deciphered, as they must have been able to operate over extremely large distances very quickly, making the use of radio a certainty.

      It is also likely that some units within the German military adopted their own "extra secure" practices when using the Enigma system internally. These may or may not be crackable, depending on how paranoid the commanders were.

      • Colossus had nothing to do with cryptanalysis of any Engima variant. The Colossus machines were used to help break the more advanced Baudot code teleprinter systems used for communications between German command posts - particularly the system known to the Allies as 'TUNNY'
      • by Convergence ( 64135 ) on Sunday February 26, 2006 @04:53AM (#14803199) Homepage Journal
        Enigma has a fatal flaw: No letter could be encyphered to itself. This is an artifact of the 'reflector disc' at the end this means that a known plaintext, or crib, can be ruled out for a particular offset, if any letter of it matches a letter in the cyphertext. This, combined with message statistics, allows for powerful cryptographic techniques to be used. [] These techniques were unavailable in WW2, but they exploit fundamental weaknesses in the design.

        Of course, in WW2, it was the misuse of enigma that made it particularily easy to break --- It might only take one weather report to learn the daily subkey. Had Enigma been properly used, it would probably have been nearly unbreakable with WW2 era technology.

        • Of course, in WW2, it was the misuse of enigma that made it particularily easy to break --- It might only take one weather report to learn the daily subkey. Had Enigma been properly used, it would probably have been nearly unbreakable with WW2 era technology.

          One tactic they used was 'Gardening' where they sent out bombers to mine a particular sea area, then sit back and wait for standard message reporting the new minefield

        • by Peter H.S. ( 38077 ) on Sunday February 26, 2006 @10:15AM (#14803760) Homepage
          While it is true what you say, I will point out that "enigma" messages originated from a lot of different networks, all with their own codebooks, eg. Luftwaffe (airforce), Abwher (intelligence), and Hehr (army) messages etc, where all encoded with different keys. These different networks where further segmented into theater of operations, meaning that breaking Hehr enigma messages from North Africa, would not yield the key for reading Hehr messages originating from France. Further more, all keys would changed daily, meaning that the British would have to start all over every day.

          So getting the daily subkey from a bungled weather report, would only help the British to read messages from a particular branch, in a limited area, for a period of just 24 hours.

          Peter H.S.
      • Have you got a reference for that "10 times faster than a p4" quote? I saw that and was impressed, but I looked colossus up on wikipedia [] and apparently colossus used 1500 valves.
        A valve does the same thing as a transistor, and I find it extremely hard to believe that 1500 transistors, no matter how cunninly arranged to execute a single algorithm, could outperform 55 [] million transistors.

        And I also doubt if they were switching several thousand million times a second.
        Yes, I know, many of those transistors are
      • You're confusing Colossus (with against Baudot codes) with Bombes (used against Enigma) and, indeed, the Baudot Codes (Tunny, Sturgeon) with Engima. It's difficult to unpick your confusions, but I assume that the massively parallel devie you allude to is Turing's Bombe, fitted with Welchman's diagonal board. [[ Before someone comes in with more mis-information, Turing's bombe attacked conjectured plaintext, using the non-clashing property caused by the reflector wheel, while the Polish bomba attacked the
      • > The Enigma code was broken ...

        Lots of errors in your post: All of the methods used in World War II were short-cut algorithms. For example, bombes would search systematically over all starting positions and orderings of the rotors, but not over the billions of plugboard settings. Colossus wasn't used for Enigma. It would seem Alan Turing never used Colossus. Colossus was not faster than a P4 (unless you program in Javascript, as Tony Sale does). Sometimes operators did not randomize their rotors between
  • by rev_sanchez ( 691443 ) on Sunday February 26, 2006 @03:14AM (#14803014)
    Be sure to drink your Ovaltine.
  • by Quiet_Desperation ( 858215 ) on Sunday February 26, 2006 @03:43AM (#14803058)
    Can't I just buy war bonds or something?
  • Isn't it a bit late to be helping the war effort? It's been about 60 years since the war was over.
    • Isn't it a bit late to be helping the war effort?

      You'd think they could just ask the Germans for the cleartext.

    • I wouldn't say that, considering one of the uncracked codes could read:

      "hoax successful... I'm not really dead... several discovery channel specials prepared to skew and obscure my whereabouts... love hitler" :)
  • "The Enigma Machine was cracked in Poland in 1932,"

    I read that and burst out laughing immediately thinking of three Polish soldiers running with the Enigma machine backwards and falling over and cracking the case.

    "oh no we have cracked ze case"

    "lets get out of here"
    • Actually it was 1942 - a rather important typo. Hell, the Nazis had not even come to power in 1932.
      • by kiwi77 ( 957316 ) on Sunday February 26, 2006 @05:21AM (#14803236)
        Actualy, if the Poles hadn't been REALLY proactive about truing to break the German Enigma we (the Allies) would have been really fucked. The French had access to Enigma plans but felt that it was impopssible to crack Enigma so they handed all their data to the Poleish intelligence service (Burio Szyfrow)and siad good luck.. Marian Rejewski of the Burio developed an attack on Enigma (absolutely brilliant!!) that actually suceeded in cracking the cipher. The Poles were decrypting German messages on a daily basis until 1938, when the Germans increased the number of scramblers to 5 so that any 3 were available for encryption and also added new plugboards. When Poland was attacked by the Germans the Poles called in the British and gave them spare Enigma replicas they had built, blueprints, and cracking strategies. They were sent to England in diplomatic pouches via Paris. smuggled across the Channel by a French playwrite and his actress wife, so as not to be detected by Geman spies at the Channel ports. Laugh all you want to, but the Poles made it possible to win World War II.
        • Well, I think the fact that the Germans attacked Russia/Soviet Union, instead of just going on and taking over Britain made it a lot more likely for them to lose WWII...

          Even though they had a chance of winning, the cost was very high.

          If they had done it the other way round, they'd have much of western Europe, and there'll be just USA, Germany, USSR in the North Atlantic.

          • hey, you forgot Canada!

            most people only forget Poland, but Canada?
            • Isn't Canada the northernmost state of the USA? Just like Australia is the southernmost? ;)

              Anyway my point was it would have been much easier for Germany to take all/most(switzerland?) of western europe if they didn't expend so much trying to take the Russians.

              Fighting a war on more than one front is difficult. The Russians weren't going to attack them in the first place. So they should have just gone and taken west europe (including britain and ireland) and that would make it a lot harder for the USA to tr
        • Laugh all you want to, but the Poles made it possible to win World War II.
          You're making a lot of unwarranted assumptions. You're assuming that Britian or the US wouldn't have broken Enigma by themselves, which seems likely given how many other difficult ciphers they broke (e.g. Lorenz, Purple). You are also assuming that without breaking Enigma the Allies would have lost the war. That's extremely contentious.
  • Cool, I'm re-reading Cryptonomicon and this goes right along with that. I like how Neal Stephenson's books merge so well into real science and history. The only trick is in remembering which is true and which is fiction. :)
    • Turing could have accomplished a hell of a lot in the following years. Who knows? We might have seen genuine early advances in AI, since he was showing an interest in it.

      • I think in this there is a lesson, which has something to do with gay people, and no persecuting them.
        Something the US (and Iran!) still hasn't learnt yet. Ah well.
  • asdfasdfahdfhrlfslfdjfjjhsjdgsfduyghsudighsdhgshgs dkghksfdgkjsfgklsdhfglkshglsghgkjldhlkjdhhahahahai rule
  • by Yeechang Lee ( 3429 ) on Sunday February 26, 2006 @06:16AM (#14803348) Homepage
    After putting a Beowulf cluster to work, I've deciphered the remaining two unsolved Enigma messages. It turns out that one is a reply to the other. Of course, one can never be sure whether a decryption is correct, but the perfect German in the messages convinces me that I've got them right, as you can see:

    "Sieg Heil! Zis is U-571. Ze Amerikan destroyer is pwning us! After zat last depth charge, all our blinkenlights are flashing crazily! What do we do?"

    "Achtung! Achtung! Brest here. Unfortunately, ze RAF Bomber Command pwn3d us last night and ze submarine pens are kaput, so you cannot return from your tour early. Remember, Kapitan, what happens to schweinhunds zat are cowards; zhey get sent to the Russian Front! Follow the example of your Luftwaffe friend Colonel Klink and watch out, or you will be given ze boot from Das Boot!"
  • by baudbarf ( 451398 ) on Sunday February 26, 2006 @06:17AM (#14803351) Homepage
    Doesn't the DMCA make it illegal to make tools for breaking encryption or even to discuss how encryption may be broken? Aren't those among us who are americans all conspiring to break federal law by attempting or discussing the possibility of attempting to break these enigma messages?

    You're all terrorists. Off to Guantanamo with you.
    • You may want to read up on the DMCA, which makes it illegal to make or distribute technology that may be used to circumvent copy protection. I know making irrelevant references to DMCA has been flavour de jour on Slashdot for the past 5 years, but it doesn't have much at all to do with encryption in gerenal (only certain kinds/uses of encryption).

      Since it is unlikely that anyone would consider using Enigma for any kind of copy protection or DRM, breaking Enigma would not be a problem for DMCA. Even if som
      • Most distributed projects to crack encryption schemes (which are generally used for copy-protection) are fine, because they only crack the key for a limited set of messages, so cannot directly be used to break copy-protection.

        Well -- I think you may be overstating the case. Notice that you've left out the possiblity that DMCA, while allowing brute force attacks to recover specific plaintexts, makes it illegal to study the cryptographic weaknesses of various algorithms, which so far as I know it does not.

      • The people cracking these messages didn't write them and since they were written in the 1940's the original copyrights haven't expired. The coded messages were obtained, copied and distributed against the wishes of the original author. Certainly the messages were encrypted as a form of rights management and protection. I think breaking the code migt very well violate the DMCA.
    • Doesn't the DMCA make it illegal to make tools for breaking encryption or even to discuss how encryption may be broken?

      No. You're letting them control you because they always use the acronym.

      It is the Digital Millennium Copyright Act. It is first, foremost, and only a copyright act.

      The Enigma messages aren't copyrighted in any real sense (copyrights that belonged to the Nazi Party went to interesting places - at one point they were public-domained by an Allied government as "spoils of war"), and moreover t
  • by droopycom ( 470921 ) on Sunday February 26, 2006 @06:20AM (#14803354)
    I've heard from an anonymous source in the US intelligence community that British Intelligence has informed the White House that the newly decrypted enigma messages contains information regarding Irak WMD locations, and clear indication of the Saddam-Osama link...

  • Enigma simulations (Score:2, Informative)

    by Dirk DefCom ( 957326 )
    I you would like to use an Enigma machine yourself, just go to this website: [] There's an awardwinning Enigma simulation. This program is an exact simulation of the 3-rotor Wehrmacht and the famous 4-rotor Kriegmarine M4 model of the German Enigma cipher machine, used during World War II from 1939 until 1945. You can select between the two models, actually choose different rotors or 'Walzen', preset the rotor wiring positions or 'Ringstellung' and switch letter
  • by Linker3000 ( 626634 ) on Sunday February 26, 2006 @06:40AM (#14803388) Journal
    The second message has now been cracked and it contained three interesting bits of 'technology history'...

    It warned other units that a local garage mechanic had offered to 'improve' their Enigma machine to make it run faster, but after he left they discovered he'd inserted a small additional module which meant that whatever was transmitted, there was an extra last line which read "Come to Fritz's autos for a great deal on used Volkswagens". The cracked message told all other users only to visit trusted garages and not accept any offers of performance upgrades because such offers were the work of 'trojan enemy conspirators that operated like an unwanted virus in the body of our glorious Fatherland'.

    There were also complaints of many false messages being received that decoded into offers to supply the German solders with 'processed meat rations' captured from allied troops - the cracked message warned Enigma users to ignore the flood of 'unwanted messages about spam that deflect focus from our vital war efforts' and not to reply as this only confirmed that the messages were being received, which guaranteed even more 'spam messages'.

    The final bit of the decoded message related to trials with a new rotor wiring system produced by a local engineer. Apparently, the system promised to make the Enigma machines easier to use, but the coloured insulation on the wiring was rubbing away, (presumably an interaction between the synthetic dyes being used with early, less stable plastics), exposing the conductors and causing the whole machine to short circuit and stop working ('die' as the message coldly put it). The cracked message warned other users to check their rotors to see whether they had any of the 'brightly coloured experimental wiring' and if so, to stop using them and return the rotors to 'Wilhelm Gatz' if they identified the so-called 'blue screening of death'.

  • Who says breaking Enigma doesn't take much time???? 4 out of 8 possible naval rotors, 26 positions, each have also 26 internal ringsetting, two different reflectors, you also need the startposition and the plugs, up to 10 pairs of 26 (only the plugboards gives us already 7,905,853,580,625 combinations). Even today, going through all possible keys is a mission impossible. That's why Stefan used the Hill Climbing Algorithm to break those messages. Pure Brute force would take far to much time. More on the Enig
  • by fdiskne1 ( 219834 ) on Sunday February 26, 2006 @08:50AM (#14803613)
    Dear Sir,


    I am certain this message comes as a suprise to you since you do not know me. I have obtained your name from French Resistance fighters as one that can be trusted with my confidence.

    Two months ago, my father was kidnapped and murdered by the Nazi SS. I have need to transfer the sum of US$25,000,000 (twenty-five million) from an account in Credit Lyonnais in France to an account outside of German territory, of which your payment shall be 30% if you agree to our proposal...
  • I'd like to contribute to the project but it doesn't have a Boinc [] client? Other than the original project page, all I could find is this [] and it doesn't say anything about Boinc. Too bad. You'd think they'd try to take advantage of the large install base rather than require people to install an additional client.
  • I plotted the approximate location of the german sub at the time they transmitted the message & were following the "enemy." (Based on information from the translated original enigma text.),+4 1.35+W&ll=51.289406,-41.308594&spn=52.133005,175.7 8125 [] Kind of neat to look at.
  • As usual, site slashdotted. But I get a download, eventually - and it's corrupted. Or is it encrypted ? ;)

    Why can't people just use bittorrent for this sort of thing? Isn't it obvious that coral cache doesn't work?
  • First, nice to see them using Secondly, does anyone know of a good writeup about how a human cryptographer would go about breaking an Enigma code? After reading irst-break.html [], it's left me wondering how the humans did it.
  • There has been lots of history around the Enigma machine, but little surrounding the Allies use of codes? Is that because the Allies didn't use sophisticated coding, or its still classified, or it just isn't as interesting? I'm curious!
  • There were several different systems, used by the Allies. For high level traffic, the US used the very secure SIGABA (never reported to be broken, back then). SIGABA was also a rotor machine, but with three different banks of rotors, each performing their special task. In the field, the US Amry used mostly the M-209 Convertor. This was the US version of the Hagelin C-38. It was a so called pin-and-lug machine. You can try out the M-209 on this website: m []

Sigmund Freud is alleged to have said that in the last analysis the entire field of psychology may reduce to biological electrochemistry.