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Initial problems[edit]

A good start to this page. There are some problems, however. From memory then,

1). The bombe (in any Polish, British, US variation and whatever the spelling) was not a computing device in any signficant sense. No programmable operation, no decision elements (ie, branching on a condition), etc. It (they) were essentially reverse Enigma machines (in multiples per bombe), and served only to test possible keys (ie ground settings plus whatever message key (ie session key in modern terms) might be used. Saved much time and very valuable and so on, but not computing devices.

Well, there was STOP condition there. But even if not computing in the "calculation" sense, definitely it was an information processing device (input->processing->output) ?
Lysy 09:01, 30 Apr 2004 (UTC)
Well... Depends on your definition, of course. But by a sufficiently broad definition my cat is a computer when she decides there's not enough of her favorite food and protests. The general definition is now programability, memory, branching capability, and so on. See the article on the Colossus and its Talk page for some discussion on this point. Likewise, some of the history of computing hardware articles. ww 14:15, 30 Apr 2004 (UTC)
I also think "computer" is too strong a term here, but it was a device for mechanising deductions (in the case of the UK and US bombes). — Matt 02:47, 20 Aug 2004 (UTC)

2). The first widget used by the Polish BS was called 'cyclometer'. It became unusable as the Germans changed their procedures from '32 on and was replaced by the first bomba (s).

Cyclometer was useful until September 15th 1938, when German coding procedures were changed. It had to be replaced by "perforated sheets" and bombas.
Lysy 09:01, 30 Apr 2004 (UTC)
We should say so, and say why (briefly, if possible). ww 14:15, 30 Apr 2004 (UTC)
I believe the cyclometer was used only to generate the catalog of cycle characteristics corresponding to various rotor orders and positions. This catalog was then the tool which was used to break Enigma settings. The reason it was replaced was that, rather than using a common, global ground setting to encrypt the indicator, the operator chose his own setting at random, and sent it in the clear, along with the encrypted indicator. I'll try and work on this article soon. — Matt 02:47, 20 Aug 2004 (UTC)

3). When the German Army went from 3 possible rotors in some specified order to 3 out of 5 rotors in some specified order, the increased problem faced by the Poles was not a theoretical one, it was a practical engineering one. The bombas they had would take too long against the increased possibilites (the 3 of 5 rotors) and new bombas which would take a practical time would be far more complex and take too long to design and build then they thought they had either time or money to handle. Hence, much of the reason for the handoff to the British and French in mid '39.

I think the Poles preferred the perforated sheets to the bomby, especially when the number of plugboard connections were increased. But yes, they didn't have the resources to make 60 (instead of 6). — Matt 02:47, 20 Aug 2004 (UTC)

4). Bomba/bombe/bomb (s) continued to be used against Enigma traffic till the end of the War. They were not made obsolete by the acquisition of an Enigma plus auxiliary material from any source, including a U-boat.

5). The problem confronted by Turing et al in Hut 6 at BP had been different in kind and difficulty from the start. Naval Enigma had, since the Navy adopted the Army modifications to commercial Enigma in ('32?) (replacing their own version adopted in ('28?)) always used 3 of 5 rotors, and furthermore had always used a much more complex and harder to analyze method of setting session keys. In short, their "key scheduling" was much better than the Army/Luftwaffe/SD etc. Seizures of material (from U-boats in various places, from the Krebs in the Loftein Islands (sorry about the spelling if it's wrong), from the weather trawlers off the coast of Iceland, etc were helpful in getting past that key scheduling. Though they only got through it intermittently, and were blacked out for long periods.

6). On the 'political' side, it was apparently, the determination of the USA and USN to build their own bombes that finally compelled BP/Secret Service to allow US participation in the Enigma operation; full information on techniques and allowing US personnel to assist and so on. In fact, both the USA and USN eventually built ambitious (and much faster) bombe variations (very large physically and so fast there were serious brush making contact reliability problems with them) bombes. Some were made in Dayton at NCR.

ww 14:05, 28 Apr 2004 (UTC)

A second US Bombe[edit]

Source for the believed existence of another US bombe was Jack Ingram, Curator of the National Cryptologic Museum, during a tour of the museum on Thursday. He told of searching for it and not finding it whole, but noted that they can be broken down into many smaller pieces and thought that it may be buried in storage somewhere which just hasn't yet been discovered. I forget who he mentioned as his source for there being two of them. Jamesday 20:10, 18 Jun 2004 (UTC)

Rejewski wiring solution[edit]

I removed the following:

The system developed by Marian Rejewski in the 1930s could have worked out their wiring but because the Polish cryptanalysts had briefly been in occupied France it wasn't believed safe to trust them.

Reason: Rejewski's recovery of the wiring of rotors I, II and III was based on the doubled indicator system with a common ground setting, in use by the German Army and Air Force until 15 September 1938 and the Navy until 1 May 1937; after that, his original attack couldn't be applied. (As an aside, wheels IV and V were introduced on 15 December 1938; Rejewski broke these because the SD Enigma continued using a common ground setting for a few months after the other services changed.) They got hold of the wiring for the Navy's rotors VI and VII captured from the crew of U-33 on 12 February 1940.

Principle of the bombe[edit]

I removed the following:

A cryptological bombe is essentially a large number of cypher machines in parallel, each decyphering a given message using different keys. By using dozens or hundreds of machines at once, prospective keys can be attempted in bulk, and the product from each of the decipherments can be screened for plaintext phrases which would indicate that the correct key was used. The British were concerned with the radio traffic of the German Navy, who used relatively strict procedures for encryption; the technique of loooking for a repeated three-letter wheel setting would not work (as it did for the Army Enigma), and naval Enigmas changed their daily settings based on predetermined schedules, transmitted by courier to ships while in port.

This is where the known plaintext attack became useful. No human could screen the tens of thousands of keys attempted by the bombes on a daily basis, but the machines could be configured to automatically detect common paintext phrases, most often "EINS" (German for one), or "HEILHITLER". Upon decrypting such a phrase, the machines were configured to halt and make the operator aware of the potential hit.

I'm afraid this has a number of problems. 1) A single bombe examined the keys in series, not in parallel. Although there might be a dozen Enigma-equivalents used at each point, each rotor setting was examined in sequence. 2) The bombes were used for most Enigma traffic, not just that of the Navy, since the double encipherment indicator procedure came to an end in May 1940. 3) The bombes did not recognize plaintext. The bombe performed logical deductions on a known plaintext and flagged those which did not lead to a logical contradiction. — Matt 09:17, 14 Oct 2004 (UTC)

Bombe revisions[edit]

We should talk about the revisions to bombe. I was trying to give an explaination without the hand waving so people could get the gist of the idea. Admittedly, it was oversimplified. I also don't understand why you excised my description of the Stecker board. The sentence you left has no context. Perhaps we could negotiate a joint text. My e-mail is areinhold "at" --agr 16:22, 11 Nov 2004 (UTC)

Sure; the problem was that your description wasn't just oversimplified, but (I'm afraid to say) it was actually incorrect. But I do think hand-waving gists are good, and I think it's a good idea to start off with such a summary before lurching into a description of the nitty-gritty detail of how it worked. I'm very happy (in fact, prefer!) to work collaboratively (after all, this is Wikipedia ;-) ). — Matt

I thought the model i described was a good introduction to the concept. Maybe it would help if you could say what you thought was incorrect about it. --agr 19:08, 11 Nov 2004 (UTC)

Sure; your description said If one had a guess, say that the letter G as input should produce a letter K as output, one could connect a voltage to the G input of the spinning set of rotors and use the K output to stop the motor. The stack would then spin until there was a match. — if there was no plugboard, such a machine would have worked, but this is not what the bombe did; the plugboard stops you from knowing the input and output to the rotors. So Turing had to come up with something a little more subtle. — Matt 19:27, 11 Nov 2004 (UTC)

I thought I tried to say that, but i wasn't as emphatic. I'd be up for reworking the section to make that clear. Would you, like to see it first? I can put it here or the discussion page for bombe. --agr 15:47, 12 Nov 2004 (UTC)

Sure, I'm going to be away for the weekend, so please do go ahead and work on the page as you think is necessary, and I'll have a look on Monday and make some more changes and additions myself. — Matt 16:04, 12 Nov 2004 (UTC)

Computer or not?[edit]

It would be nice to know whether or not the Bombe is considered by experts to fit into the definition of a computer? If so, we should replace the "Category:Computer hardware" with "Early computers". If not, we should arguably rm the article from the former category. --Wernher 14:35, 4 Dec 2004 (UTC)

I don't know of any expert comment either way — it does fit into the first description given at computer: A computer is a device for making calculations or controlling operations that are expressible in numerical or logical terms. The bombe makes a calculation that is expressible in logical terms. However, I wouldn't call the bombe a computer, for whatever that's worth. It's certainly common in books about WWII cryptography to label Colossus as an early / the first computer, but not to describe the bombe in that way (even though the bombe was built earlier). — Matt 20:33, 6 Dec 2004 (UTC)

What a polished article![edit]

Ground 01:22, 9 Feb 2005 (UTC)

ok Matt, let me rephrase: (pls edit and state ambiguity) I think this is a good verbal explanation !!

Assume you find a triple loop abc, ideally in plain: abc, cipher: bca.

plaintext : a big cool

cipher  : b cxy aqwe

a-b b-c c-a = a closed triplet (A-B-C -->A) OK?

So with a crib you find plaintext letter a mapped to cipher b, plain b to c, and plain c to cipher a again within short distance .

Now assemble the rotor mechanisms of three enigmas serial-in-line (abovementioned triplets) and set it to the original rotor positions,

with their offset (here 1 step each) accordingly. Then you get a corresponding physical wire closed loop from the input of the first triplet to the output of the 3rd triplet. {Now this in fact is turings cool idea ! try to understand this and ure a genius too ! no really, the letter loops corrspond to physical wire loops which can be detected by a el.circuit quickly }

You can detect this with lamps connected to the rotor contacts. {wire 'em up to + and - pole}

The lamp in the wire loop will stay dark. {meaning triplet fit}

Now you turn the rotor systems synchronously. {this is called decryption, to find da rotor position}

If only one lamp stays dark because of the one wire loop, you can quickly calculate the Steckerfeld, and reject those positions with all lamps lit. As mentioned, this typically happens several times in 17000 permutations.

It's not clear where the lamps are connected, nor is it clear why the lamps stay dark. Moreover, the Bombe didn't use lamps. — Matt Crypto 10:30, 11 Feb 2005 (UTC)

oddity of display formatting[edit]

The Engima box, center column (more or less) early on in the article, is out of place an doverlaps some text. Or, the text line overlaps the box. Either way, someone who understnads the WP mechanisms might take a look and move it a bit down with respect to the text. ww 05:32, 19 July 2006 (UTC)

The Challenge of the Four Rotor Enigma Machine[edit]

Changed the heading to reflect what this section is actually about.

Is there a mistake in "reasoning about steckered values?"[edit]

It says in the text that "we can also observe that T encrypts to W at position 2". It appears to me that T encrypts to S. However, I didn't want to change it in case I had misunderstood. Can someone comment here please?

It's now fixed I see.DI Ramekin 16:01, 3 November 2006 (UTC)

Heath Robinson[edit]

Why is there this irrelevant link?

It was pointing to the wrong Heath Robinson ;-) — Matt Crypto 06:45, 7 March 2007 (UTC)


Is it pronounced the same as "bomb", or is it two syllables, or what? If anyone knows, please add this information to the article. 12:53, 25 August 2007 (UTC)

Nearly six years to the day you have an answer! It's two syllables. Using Google language tools the Polish is pronounced quite clearly as "bomba" with a short a. See my post below for further discussion on the word. Nodekeeper (talk) 08:47, 29 August 2013 (UTC)
Unfortunately this does not appear to be correct. The youtube videos of Tony Jarvis, a bombe reconstruction engineer, and even better, Jean Valentine, one of the original bombe operators, have them both clearly pronouncing it the same as English "bomb". So, one syllable. Runox (talk) 11:59, 10 September 2015 (UTC)
One syllable for sure. Visit Bletchley Park and speak with the people who rebuilt a working one, they all say it (as the English word) "bomb". AldaronT/C 15:04, 10 September 2015 (UTC)

The Bombe and Enigma Decoding machines were found by the Poles and the Colossus machine which was the very first ever electronic computer but it's been remade.

Well it was found in 1940 before the USA had entered WW2 also as far as I'm aware that they'd disregarded the decoding work of Alan Turing and his colleagues not forgetting the WRENS. Sadly due to this the Americans lost a lot of their US Navy and USAF also the merchant navy.

But I have seen these machines recently. It's a fantastic memory —Preceding unsigned comment added by Feline23 (talkcontribs) 22:53, 23 September 2008 (UTC)

Photo of British Bombe[edit]

Are there no original photographs of the British Bombe, only of the cardboard mockup? TedColes (talk) 16:22, 6 January 2009 (UTC)

While this is an old question, the answer is yes there are and I note that the article does not include them.

There is another similar image. But both are Crown Copyright. (talk) 00:20, 3 February 2015 (UTC)

Bombe and bell?[edit]

Does anyone have a source for the statement that the British (as opposed to the American) bombe rang a bell when it found a stop?--TedColes (talk) 12:00, 19 March 2009 (UTC)

Origin of the name[edit]

Am I missing something or can it really be true that in the whole of this article the origin of the very puzzling name "bombe" and its wacky spelling is never explained? I know it's from bomba kryptologiczna but it's not explained there either. Flapdragon (talk) 10:46, 4 August 2010 (UTC)

There are quite a number of possible explanations given in various publications, none of them very convincing. By all means do the research and add in a paragraph. I would hope that it would be comprehensive, as that would illustrate how weak the historical evidence is. The spelling is easily explained as being French, presumably to distinguish it from the Polish machine and not confuse with explosive bombs. --TedColes (talk) 14:43, 4 August 2010 (UTC)
I was wondering about this myself. I'd be willing to bet that the French spelling of "bombe" comes directly from the quite similar Polish pronunciation "bomba kryptologiczna".
Interestingly there is an Wikipedia article concerning this very machine. This needs to be incorporated into the Bombe article. A task for another editor or when it is possible to find the time Nodekeeper (talk) 09:11, 29 August 2013 (UTC)

Scrap mathematical notation?[edit]

I don't think that using mathematical notation is particularly helpful to the average reader in explaining how the bombe works. What do others think? --TedColes (talk) 05:41, 21 April 2011 (UTC)

The first German WW2 Naval ENIGMA M4 TURINGBOMBE break since 1945[edit]

This project broke 17 !! Enigma M4 messages from Uboat U534 the last two weeks. They used a software Turingbombe. More messages will follow. They used 112 CPU cores.

Project website: (talk) 11:20, 14 August 2012 (UTC)

US Army Bombe[edit]

Is the US Army Bombe still in existence or was it scrapped? --Richard Arthur Norton (1958- ) (talk) 15:59, 22 November 2012 (UTC)

bomba, bombe[edit]

Polish is a phonetic language meaning in "bombe" or "bomba" "a" and "b" are spelled out. In case of "bombe" it is accusative case of "bomba" - "I have bomba", "I saw a "bomba" etc.("e" should have a "coma" on the bottom of the letter and it's spelled something like "eu"). — Preceding unsigned comment added by (talk) 12:19, 28 May 2013 (UTC)

That would explain the spelling and perhaps the name as well, following this citation from the Bomba (cryptography) article;
A machine called the "bombe" is used to expedite the solution. The first machine was built by the Poles and was a hand operated multiple enigma machine. When a possible solution was reached a part would fall off the machine onto the floor with a loud noise. Hence the name "bombe".
By your explanation of the Polish accusative case of "bomba" would fit in with this anecdote and essentially be "I saw the cryptology [machine] bomb"! So, it would follow that a possible english analogue would be "cryptology bomber". But this would be bordering on WP:NOR The pronunciation no doubt comes from the French spelling of the Polish "bomba" as they both sound quite similar!
It would be great if a university professor reading this could give a student extra credit for follow through on this and update the Bombe and Bomba (cryptography) articles (with pronunciation and etymology of "bombe") as I am time constrained. Nodekeeper (talk) 09:52, 29 August 2013 (UTC)

Polish Contribution[edit]

My understanding is that the Poles started this and then when they fled to England Turing et. al. developed it further to cope with the ever more complex enigma. The article makes it seem like the English system was developed independently from the Polish one. Needs to be clarified one way or the other. (talk) 03:02, 4 February 2014 (UTC)

It is correct to say that the Poles started the decryption of Enigma, and that without their achievements, the British would not have achieved anything like as much as they did. I don't, however, read the article as implying that the Polish contribution was unimportant. What is clear is that the Turing-Welchman Bombe was not a straight development of the Polish Bomba, as it worked on a different principle.--TedColes (talk) 10:10, 4 February 2014 (UTC)

Someone should reconcile the Polish contribution aspect (to the Bombe) between this article and the one titled "The Imitation Game" which says, "It was originally designed in 1938 by Marian Rejewski, who along with other Polish cryptographers had successes in decrypting Enigma messages during the 1930s. They were then blocked by a lack of scalability to deal with complexities resulting from changes in German equipment and procedures. A new machine with a different strategy was designed by Turing (with key contributions from mathematician Gordon Welchman, unmentioned in the film) during 1939 and 1940. The building of the British machine itself was led by Harold Keen.[93][91]"

Perhaps part of the problem is with the use of the word "It" in the Imitation Game article. Regardless, both articles should appropriately distinguish between the two different machines, properly describe their relationship, and give appropriate credit.

Techguy95 (talk) 05:48, 22 January 2015 (UTC)

Drum order[edit]

There has bee a bit of toing and froing on this fragment from the article. The words 'left' and 'right' being interchanged. The fragment currently reads:

The bombe drums were arranged with the top one of the three simulating the left-hand rotor of the Enigma scrambler, the middle one the middle rotor, and the bottom one the right-hand rotor.

Unfortunately, this does not square with the next two sentences nor with any film of video footage of the bombe in operation. It also does not square with the internal mechanism of the bombe where the top rotors are directly driven by a common drive shaft via worm gears. The middle row rotors are moved by individual mechanisms from the top rotor and simialarly for the bottom. This means that the top row rotor are fastest moving. Similarly, it was the right hand rotor in the actual Enigma machine that was the fastest moving.

Also the same paragraph gives the period as 26x26x26. But this is not correct because of Enigma's 'double step' of the middle rotor when the left rotor moves. (talk) 16:40, 20 January 2015 (UTC)

Look at the reference. Tony Sale said:

"Remember that the top, fast, drum on the Bombe corresponds to the slow left hand drum on the Enigma machine."

--TedColes (talk) 18:39, 20 January 2015 (UTC)
The answer is what the sources say, and Tony Sale appears to be a reliable source. Sale says the bombe spun the left hand rotor fastest (different than the Enigma). It didn't matter which order was searched because the bombe searched the increments in parallel.
When the bombes searched for cribs, they ignored the ring settings (which caused steps/double steps) and hoped that there was no step during the encryption. Consequently, the bombes would search all 263 permutations. Glrx (talk) 00:03, 21 January 2015 (UTC)
The bombe was searching for the initial Enigma settings. In this respect, the search order of settings does not matter. Why they chose to make the slow rotor on the Enigma, the fast rotor on the bombe is an unanswered question.
The double step is irrelevant in this context. The bombe, as I said, is searching for the initial settings of which there are 26x26x26 possible start positions for the three rotors. The double step may come into play once encryption/decryption begins but not when the Enigma is first set up. DieSwartzPunkt (talk) 17:19, 22 January 2015 (UTC)

The comments above have not made sense to me because, as best as I can understand it... The enigma protocol was in essence a short message system (the manual states maximum message size to be limited to 250 letters, which meant 50 groups of 5 letters), this would make it likely that the left hand (slowest) rotor woud not rotate during a 250 character message and any concept that suggests the message could be cryptoanalysed and decrypted by searching via left hand rotor simulation simply could not be correct, could it?

If the Bombe is an Enigma simulator then surely the fastest 'Bombe Drum' would be simulating the fastest 'Enigma Rotor'. I have not seen any reference anywhere to the Bombe being an inverse simulator. I do understand that some methods will be counterintuitive, but how could searching for a solution within part of the mechanism that is not moving, or at most moving once during a message, reveal the data required? (I could imagine the possibility but I would be grateful if someone could explain it, if that it the case).

I understand the rotors have a 26x26x26 cycle but am slightly confused by the simplicity of the 26x26x26 electrical permutations analogy because surely the mathematics become more complicated every time two rotors move together and create a 'double transformation event'?

Would a message be more difficult to decrypt if it contained these shifts or were these shifts invisible to the Bombe's search protocol because searching through the 17576 possible events would eventually identify candidate solutions regardless of, or before, 'double transformation events'? Were the shifts of the middle and left-hand rotors the cause for false solution candidates?

If I am fundamentally nisunderstanding the operation I look forward to gaining a deeper incite from your comments David Whois (talk) 22:36, 29 August 2015 (UTC)

Unlike an Odometer, the Enigma rotors did not have to wait for the rotor to the right to complete a revolution before it was pushed into advancing. It all depended on the position of the notches on the rings. It would be quite possible, but very uncommon, for all three rotors to have to advance on the first key depression of a message. So the Bombe drums had to cover all 26×26×26 options, which is why it did not matter that the fastest rotating drum corresponded to the left hand, slowest, Enigma rotor.--TedColes (talk) 22:14, 29 August 2015 (UTC)
Please, David Whois do not delete other editor's text without very good reason indeed. Also, read all of this section before commenting further.--TedColes (talk) 05:48, 30 August 2015 (UTC)

Bombe Simulators[edit]

Are hobbyist simulations and emulations of the Bombe worth a mention? Here is an impressive recent example:

In 2015 a New Zealand hobbyist built a desktop version of the bombe using a Raspberry Pi2 and an Arduino.

kencf0618 (talk) 22:28, 7 October 2015 (UTC)

No. WP does not report every project -- hobbyist or otherwise. The question is whether the project is WP:DUE. The reconstruction reported in the article has significant sources and is a faithful mechanical reproduction now hosted at Bletchley. There have been many software bombe simulators; see partial list in the external links section. Glrx (talk) 01:34, 8 October 2015 (UTC)
So added. Seems apropos. kencf0618 (talk) 20:54, 9 October 2015 (UTC)
No, it is not appropriate. It is a hack. It's a primary source written in the first person. WP does not like blogs. You need to get consensus on this page before re-adding to article. Glrx (talk) 21:12, 9 October 2015 (UTC)
It's been reported on on Slashdot, but oh well... I thought it an interesting reconstruction. kencf0618 (talk) 21:24, 9 October 2015 (UTC)
It's not really a reconstruction. There's a mechanical "output" device, but that mechanism has nothing to do with the bombe computation. Although the project shows effort, it does not add any clarity to the article or the subject matter. Compare efforts using bombe-like but extended simulators to attack old, unsolved, ciphers; they sometimes give perspective on how Bletchley may have chosen cribs. We also don't have any expert passing on the project. Sadly, a journal article on the Polish bomba has some glaring faults; primary sources have problems.
I'm not the last word about inclusion; it goes in if there is consensus here. Glrx (talk) 21:43, 9 October 2015 (UTC)
No problem. I was thinking along the lines of an appropriate homage/retro-computing subsection, but we shall await consensus. kencf0618 (talk) 21:49, 9 October 2015 (UTC)

Rebuild/replica of Bombe led by John Harper[edit]

The dates and duration is inconsistent with what is written on the page about John Harper. These should be in unison. — Preceding unsigned comment added by (talk) 07:56, 21 May 2016 (UTC)

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