Dorabella Cipher, first two words decrypted (perhaps)…

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Despite The Dorabella Cipher‘s brevity, its link to composer Sir Edward Elgar (who wrote it) has brought it a cult following over the years. Like other unbroken ciphers, it has appeared as a mysterious motif in TV plays, novels, and even recently in a children’s book (The Orphan of the Flames).

dorabella-cipher-image

At first sight, it looks to be merely a straightforward simple substitution cipher of the kind that pen, paper, and an agile mind should crack relatively quickly. But what is mystifying is that even though Elgar apparently used precisely the same pigpen-like (3 sets of 8 orientations each) cipher alphabet elsewhere in his writings and notes, the letter-for-symbol replacements he used there make no sense when applied to his Dorabella Cipher. The key seems to match the lock, but doesn’t open the gate.

Moreover, given that the ciphertext’s statistical distribution sits awkwardly with those of natural languages, code-breakers’ numerous attempts to shoehorn their preferred substitutions into the cipher’s three short lines come across as clunky and false (at best). Worst of all, I’m sorry to say that even prolific cipher-solver Tony Gaffney’s ingenious and elegantly-structured decryption failed to please pretty much anyone apart from him.

However, the upside to all that grim cryptanalysis is the indisputable truth that Elgar messed around with language quite a lot, typically in a playful and mischievous way. In general, he loved subverting the rules of language, speech and music, which arguably culminated in his famous Enigma Variations, which some people like to call ‘musical cryptograms’ because many lightly parody (for example) various close friends’ speech and laughter rhythms.

Yet what has long tipped my own judgment against the Dorabella Cipher’s being a cipher of any sort is that by 14th July 1897 (the date of the note), Elgar (who wrote the note) hadn’t known Dora Penny (to whom or for whom the note was written) very long at all; and they never communicated in any kind of cipher before or after that date. But even so, my opinion was no more than a hunch, based only on various modern references on Elgar’s life I’d read… not very satisfactory, but that’s how these things tend to go.

Anyway, having spent far too long reading and relying on secondary sources on this particular cipher mystery, a few weeks ago I decided to instead go right to the source of the story – Dora Penny’s book “Edward Elgar: Memories of a Variation” (I bought a copy of the 1946 second edition, which has rather more information about the Enigma Variations than the first edition), written under her married name “Mrs Richard Powell”.

What I read there only served to strengthen my historical argument against The Dorabella Cipher’s being a cipher at all. Elgar and Penny first met on 6th December 1895, and the cipher was only the third letter Elgar ever wrote to Dora (if indeed, as she points out, it is a letter at all). (Also, he only started calling her “Dorabella” in 1898, so there’s a case to be made that its name isn’t chronologically accurate… oh well!) From all I could see, it would defy common sense if he had sent her something written in an deliberately intractable cipher: no matter how much of a fascination he personally had with such things, cryptography of any sort was not a discussion subject the two friends seemed to have shared at all.

And yet what we see does so resemble an enciphered cryptogram, a paradox which ultimately gives it its place at the Cipher Mysteries top table: for it really ought to be a simple cipher, but it surely is not one. And I find it hard not to hear Elgar’s voice saying to Dora Penny exactly what he said to her about the Enigma Variations (one of which is ‘hers’) – that surely she “of all people” would be able to unwrap its central mystery, its hidden themes. Wouldn’t his cipher, too, be steganography – hidden in plain sight?

As to the content of the note, I don’t believe that the newly married Elgar would have sent Dora Penny, for all the fun they had together (going out to the races, seeing Wolverhampton Wanderers, reading maps, flying kites, etc) a love letter. So in all probability, I think that what we are looking at here is a three line note or letter from him to her, in broadly the same joking and playful manner that he adopted in his other letters to her (though probably not as Byzantine in lexicographical complexity as later letters would become), regardless of the particular manner in which that effect is achieved.

The only other clue I have to offer is that in July 1897, the Elgars were living in a house called “Forli” (named after the talented Renaissance painter Melozzo da Forli, who incidentally gets mentioned a few times in Elizabeth Lev’s rather good The Tigress of Forli) in Malvern in Worcestershire. And so I wondered whether “Forli” and/or “Malvern” might be effective as cribs into the cryptogram, for Elgar would typically head even very short notes with his current address (several of which are charmingly reproduced as inserts in Dora Penny’s book). OK, it’s not quite “HEILH ITLER” at the start of Enigma messages, but you gotta work with what you’ve got, right? 🙂

And so with all these fragmentary clues in mind, I stared and stared and stared at the Dorabella Cipher, trying to see what Elgar (mistakenly) thought Dora Penny would see straight away. And then I stared somemore. After a (fairly long) while, here’s what I noticed:-

dorabella-forli-malvern

Essentially, I suspect that Elgar was so certain that Dora Penny would know what he would be saying in a short note that all he felt he needed to do was to write the general form of the words (even presented in the form of a ciphertext-like medium) and she would still be able to ‘read’ them. [Unfortunately, this proved not to be true!] So, I believe that what we are looking at could well be more like Elgar’s improvised steganographic attempt at a mind-reading trick than a traditional ciphertext per se. Such a process would (probably) produce something like what we see: a non-mathematical stegotext that fails to have the kind of rigorous statistical profile that “proper” ciphers would.

I’m the first to admit that it’s far more of a wobbly observation and a loose speculation than a rigorous proof: but what I’m proposing is that the Dorabella Cipher could turn out to be a quite different class of object from that which code-breakers have been trying (unsuccessfully) to crack. It’s not the end of the road here, but it might possibly be the very start of one… hopefully we shall see! 🙂

1926 Budapest crossword suicide, revealed! (Mostly)…

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Several years ago, I noted here a long-standing story about a 1926 Budapest waiter who (allegedly) killed himself, leaving a suicide note in the form of a crossword. I wondered whether it was an urban legend, or (if it were to prove to be true) whether the crossword might have been printed in a newspaper of the day. But with only a few words of tourist Hungarian to work with, I didn’t really stand a chance in the Hungarian archives.

Well, now Hungarian urban legend-hunter Marinov Iván has eagerly grabbed the baton, and hurdled his way along miles of microfilm in the newspaper archives in search of the truth. As a result, his Hungarian urban legend blog today revealed that this was indeed a real story. According to the 4th March 1926 edition of Az Est, what happened was this (forgive my rough and ready translation / paraphrasing)…

keresztrejtveny

Just after (?) midnight, a man had come into the well-known Emke kávéház [Café Emke] on near the corner of Rákóczi út [Rákóczi Way] and Erzsébet körút [Elizabeth Boulevard]. After having a coffee, he repeatedly tried to call a number using the cafe’s telephone, but without success. About an hour later, the Emke’s cloakroom attendant heard a bang from a toilet: and when she opened the door, she heard a second bang. Inside, she found a young man lying on the floor with a pistol in his hand, and with blood gushing from his head and chest.

Emke1929-interior-small

Once the ambulance and police arrived, the man’s identity was found to be Antal Gyula [Julius Anthony] of Csengery utca 3 [#3 Csengery Street]. In his pocket there was [- indeed! -] a suicide note containing a crossword. It subsequently turned out that he had lived in “misery and unemployment” for some time, and had been evicted from his apartment at the start of the month, having failed to pay his rent. But as far as his note went, the Est article concluded “A bonyolult keresztrejtvényt azonban eddig még nem sikerült megfejteni“, which I read as “the complexity of the crossword means that it has not yet been deciphered“.

emke-kavehaz-small

So… what happened next? Iván followed up by looking in lots of other Hungarian newspapers from that year, but they all reported essentially the same bare facts, with only the Pest Newsletter adding that the man was 25 years old, and that the riddle had been “taken to police committee headquarters”. He speculates that had it might have had received more coverage had the man’s job been of higher status than a waiter: sadly, Budapest has long been (and remains to the present day, I believe) a suicide ‘hotspot’, so many other pages of those same newspapers would have contained stories of the same tragic ilk.

Ultimately, Iván failed to find any further references to the story in the newspaper archives, and so it is there that he stopped. Perhaps someone else will now pick up this baton and carry it yet further… perhaps we shall yet get to see Antal’s infamous (but tragically real) crossword!

PS: an Internet search revealed an evocative description of Café Emke in December 1945 in Sándor Márai’s autobiographical “Memoir of Hungary (1944-1948)” (pp.198-205).

The WW2 Pigeon Cipher… probably isn’t in Slidex. :-(

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Today I received a nice little package of stuff from Holland, courtesy of Rob van Meel, who reprints old military manuals – mostly British, but a few American and German ones too. I get the impression these are mainly for people with an interest in reenactment / war games rather than historians and researchers per se, but given a healthy area of overlap there’s surely room for everyone at the table. 😉

Unsurprisingly, I was most interested in the various Slidex-related manuals Rob had, particularly an updated release of the Slidex manual dated 1st December 1944 (i.e. six months after D-Day). You see, Slidex originated as a system where operators used only a single letter for each of the twelve slots on the horizontal cursor: yet we have later examples where two letters went in each slot (and you could choose either one to signify that column).

If our pigeon cipher is a bigram cipher, then it is one that appears to use 24 letters in its horizontal cursor. So if it was enciphered using Slidex (which seems to be the code most widely used on D-Day), it would have to have used the two-letters-per-slot version. Hence the big question I wanted to try to answer was… when did the changeover from one-letter-per-slot to two-letters-per-slot Slidex happen?

However, going through the revised Slidex manual, it became abundantly clear to me that even in December 1944, the British Armed Forces were still using single-letter-per-slot Slidex, which would seem to rule out Slidex’s having been used in the pigeon cipher before 1945.

At the same time, the two pigeons were (according to their NURP references) born in 1937 and 1940: and the older of the two would have been right at the end of its carrying days in summer 1944, let alone in 1945. As a result, the Venn diagrammatic intersection of possibility (i.e. between the [old pigeon] circle and the [revised Slidex] circle) is shrinking all the time.

Right now, I don’t know what the answer to all this is: to my eyes, what we’re looking at seems a bit more like a bigram cipher than a machine cipher, but even that’s far from certain either way. All the ‘best’ cipher mysteries seem to take a somewhat sadistic pleasure in continuously oscillating either side of the shaky line between certain and uncertain, and this one is surely no exception.

Yet there were other low grade bigram ciphers in use during WW2: two in particular were an Air Support bigram cipher and a Royal Engineers syllabic cipher. These may well be the same two variants of the Syllabic Cipher introduced in 1942 as per Stu Rutter’s page, which I believe were known as BX 724 and BX 724/RE respectively.

I’ve already written to several army museums and archives asking if they have either of these, but so far without any luck. Any suggestions as to private collectors (or collections) who may have a copy of either? Unless you have a better idea, this would seem to be the next sensible thing to check, and the various National Archives files Stu & I checked didn’t seem to have any description of it at all.

In short: probably not Slidex, so remains a work in progress. 😉

Voynich pub meet with Klaus Schmeh on 7th March 2013…

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It’s been a while, but the time has finally come round for another Voynich London pub meet, on Thursday 7th March 2013 at the Prospect of Whitby in Wapping, a pub with its own gallows and noose (though admittedly these days it’s Somali pirates who get all the press rather than privateers). I’ll be there from 6pm onwards, hope to see some of you there too!

prospect-of-whitby

The reason for the weekday (i.e. not the usual Sunday) is that German cipher mystery skeptic Klaus Schmeh is over in the UK for a very few days & the 7th is the only evening he can squeeze into his packed schedule. I can’t change that and would like to catch up with him, so what’s a Cipher Mysteries blogger to do? Make do with the cards he’s dealt, that’s what… it is what it is.

This has, of course, been Schmeh Week on Cipher Mysteries, what with The Gentlemen’s Cipher from Klaus’ blog and this week’s diplomatic cipher conference in Gotha. So if (like me) you’d like to chat with Klaus about the conference, or perhaps chat with me about cipher stuff (if reading all my posts isn’t a rich enough diet for you), then feel free to swing along to Wapping. WW2 cipher pigeon fans welcome too! Cheers! 🙂

Historical Cryptography Conference in Gotha…

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Word just arrived here by breathless carrier pigeon (well, the little chap had flown from Italy, after all) about a conference in Gotha on 14th-16th February 2013 (yes, this very week!) on historical cryptography. And here’s the rather nice conference artwork:-

gotha-conference-small

Lots of interesting sessions on all manner of European historical stuff, such as from top Italian cipher-breaker Filippo Sinagra, who you may remember from the Nat Geo “Ancient X-Files” Voynich half-episode not so long ago. Filippo’s talk is on Sforza-era cryptography, for which he patiently trawled through the Milanese archives (he very kindly passed me scans a while back). Fascinating stuff that’s right up my street, I just wish I could be there (though sadly that’s not possible this particular time, oh well!)

There’s also a talk on historical code-breaking methodology (or, more accurately, the apparent lack of anything like one) being given by a certain German cipher skeptic – yes, it is indeed that man again, Klaus Schmeh. His introduction notes that: “Publications devoted to the particular methods of cryptanalysis regarding historical ciphers are rare. The presence of numerous works in which decrypted historic secret texts are presented should not obscure the fact that a comprehensive theory is lacking in this area.” Amen to that, Brother Klaus!

Another nice thing is that Christiane Schaefer will be discussing the Copiale Cipher (which she, Beáta Megyesi and Kevin Knight successfully broke) and her team’s follow-on project, an “interactive digital platform” called “CADMUS” for early modern cryptology. All of which sounds a lot like a call to European historians to send them your enciphered early modern documents and they’ll crack ’em… or you could just send them to me c/o Cipher Mysteries, that would work too. 😉

But perhaps the wild-card of the conference will prove to be Dr. Michael Korey, whose session is intriguingly entitled “Hidden steganography and burned substitution. Some little‐known cypher equipment from the cabinet of curiosities (Kunstkammer) of Dresden”. The description (which I hope it’s ok to reproduce here) goes like this:-

“In the middle of the 16th century, the German territories were considered to be not very progressive by foreign countries in regard to their ability to encrypt their messages or decrypt those sent by others. Matteo Argenti, secretary of cyphers at the Vatican, said the Germans and their neighbours understood so little about cyphers that they preferred to shred and burn the encoded dispatches they received instead of trying to decrypt them. In retrospect, this assessment seems quite premature, considering two pieces coming from the electoral Saxon cabinet of curiosities (Kunstkammer), that so far have not attracted much attention and will be presented here.”

It should be no surprise that I rather like the sound of that. Ummm… I hope someone takes a photo or two (hint, Klaus, *cough*). 🙂

For everyone going, I hope you have a great time, it looks like a great conference!

The Gentlemen’s Cipher, solved! :-)

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Because people keep telling me nice things about Klaus Schmeh’s recently-started blog Klausis Krypto Kolumne (and there’s you thinking you couldn’t read German, tcha!), I thought a visit was a little overdue.

The first thing I saw there was his brief page on the Gentlemen’s Cipher, a cipher taken from “the papers of a gentleman recently deceased”, and printed in “The Gentlemen’s Magazine” in April 1748. (It was mentioned in Cryptologia in 1978)

At first glance it seemed an awful lot like a simple (monoalphabetic) substitution cipher; and the repeated 3-gram at the start of lines 4 and 5 was probably “THE”; hence I thought it would probably be easy to break. So for a pleasant change, rather than just passing it on to Tony Gaffney Baloney to break while his half-full kettle boils (as per normal), I thought I’d instead transcribe it and try to solve it myself. Which I did.

In the end, though, all I actually did was paste my transcription into WebDecrypto, which got sufficiently close to the plaintext in a matter of seconds that I could Google it. It turned out to be nine lines from a 1699 poem by Sir Samuel Garth – “To die is landing on some silent shore / Where billows never break nor tempests roar / etc”. All of which is somewhat coincidental: so perhaps The Gentlemen’s Magazine’s correspondent “R.M.” who submitted the cryptogram was having a gentle laugh, having concocted the story of the “gentleman recently deceased”? I think so, but make of it what you will.

Anyway, if you want to see the whole thing, I’ve put up a short page describing The Gentlemen’s Cipher here. Case closed! 🙂

Helen Fouché Gaines’ challenge cipher…

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To add to our list of challenge ciphers (Bellaso’s, d’Agapeyeff’s, Feynman’s, etc), here’s one I hadn’t seen before from Helen Fouché Gaines’ (1956) “Cryptanalysis: A Study of Ciphers and Their Solution”, which I found courtesy of Greg Ross’s Futility Closet website:-

VQBUP PVSPG GFPNU EDOKD XHEWT IYCLK XRZAP
VUFSA WEMUX GPNIV QJMNJ JNIZY KBPNF RRHTB
WWNUQ JAJGJ FHADQ LQMFL XRGGW UGWVZ GKFBC
MPXKE KQCQQ LBODO QJVEL.

The cipher is the last in a series of exercises at the end of a chapter titled “Investigating the Unknown Cipher,” and she gives no hint as to its source. Of the exercises, she writes, “There is none in which the system may not be learned through analysis, unless perhaps the final unnumbered cryptogram.” The solution says simply “Unsolved.”

If you look at the book itself (p.217), all Gaines says is “Here is one which nobody has been able to decrypt:“. Hence it is not at all clear whether this is a composed challenge cipher (i.e. designed to confound) or an accidental challenge cipher (i.e. one found in the wild but never yet solved). I suspect the latter… but perhaps someone will know for sure either way.

Incidentally, the 1968 comment on this mentioned in the Futility Closet post is online here (it’s on p.5): just so you know, the authors there offer an [entirely fictional, I expect] “Nicodemus J. Grumbow award” for anyone solving it.

As far as the ciphertext itself goes, it has a flattish distribution (Q appears 9 times, while T & Y appear only twice each, all 26 letters are used), with a standard deviation of 1.52144, i.e. much flatter than a normal alphabet would present.

It has no repeated trigrams, while QJ & PN appear three times (DO, GW, QL, GG, VQ, PV, NU, NI and XR each appear twice). There are seven doubled letter-pairs, all appearing once only each (PP, GG, JJ, RR, WW, GG, QQ). There are a few visible patterns in the text that vaguely suggest some kind of structuring (JAJGJ, QCQQ, QLQ and QQL), but all of which might just be random.

As a result, it doesn’t appear to be a monoalphabetic substitution, nor a (conventional) polyalphabetic substitution (as there seems to be no obvious cycles, loops, or repeats). The cipher text is 125 characters long, which (as a mathematician) makes me idly wonder whether this was partly enciphered using some kind of a 5x5x5 three-dimensional transposition cipher, the sort of thing a Bond villain would gloat about in his/her evil monologue. I don’t believe for a minute that this is the case, of course, but I thought I’d mention it all the same. 🙂

Any thoughts? Is there anything that suggests to you what kind of a cipher this might be?

Slovakian Voynich facsimile edition (2012)…

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I found out today that Slovakian publisher CAD Press late last year brought out a new facsimile edition of the Voynich Manuscript, preceded by 176 pages reviewing its history, apparent contents, mad theories, etc. Of course, reading Czech helps, though it contains plenty of other pictures (i.e. quite apart from Voynich imagery) should you wish to buy it as an unreadable coffee table book. 😉

voynichuv-rukopis

As far as I can tell, the author of the preface (Dr. Jitka Lenková, I believe?) seems to be hopeful that the manuscript’s origin will ultimately turn out to be somewhere in Bohemia. Well, I guess a bit of nationalist spin rarely goes amiss with your home audience: but such rhetoric would be a bit nicer if it were accompanied by a bit of, errrm, factuality to back it up, hmmm?

And no, I don’t really think the Voynich has anything to do with Jan z Lazu, about whom I’ve blogged a fair few times. Sorry again!

The Massey twins’ Phaistos Disk decryption claim…

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I don’t often cover the Phaistos Disk here, simply because it’s almost certainly more of a linguistic mystery than a cipher mystery as such. However, I was particularly taken by some aspects of the analysis offered by Keith & Kevin Massey, so it seemed well worth discussing here.

Incidentally, despite their complementary-yet-competing philological interests, the twins didn’t start their Phaistos Disk adventure together. But, as they put it, “for Kevin to collaborate with his brother Keith was finally inevitable, like dancing with your mad aunt at a wedding reception.”

Their Chapters 1-4 summarize a whole load of Phaistos research, while trying to argue for a link between various early European scripts (Cypriotic, Linear B, etc). Their Chapter 5 (pp.48-56) argues for a left-to-right reading of the Phaistos Disk (but not quite as convincingly as they hope, I think). But after all that, their Chapter 6 discards pretty much all their preceding linguistic analysis and instead proposes the hypothesis that Phaistos Disk words with slashes are actually numbers. And that’s essentially where they finish.

Now, for all the twins’ obvious linguistic smarts, I have to say I just don’t buy into this – at least, not in the way it’s currently presented. And here’s my argument why:

(1) The way that the signs are physically imprinted / stamped into the soft unfired surface of the disk is clearly systematic (i.e. it’s a consciously prepared set of shapes, not one that’s being improvised on a shape-by-shape basis), and the choice of those shapes forms part of the same system.

(2) Furthermore, the whole disk had to be fired once and once only. Hence without much doubt the imprints on both sides had to have been made at the same time using the same basic system.

(3) Regardless of whatever direction you believe it was written in, there are substantial word differences between the two sides. Many words repeat on the same side (in fact, there’s even a three-word pattern that repeats on Side A), yet only a single measly three-imprint word repeats between sides.

(4) There is an imbalance between the shapes on the two sides. The most obvious difference is the frequency of the plumed head imprint: 14 instances on Side A but only 5 instances on Side B. Yet there are plenty of others, such as the beehive (once on Side A but five times on Side B). Indeed, the most visually striking difference is the twelve { PLUMED_HEAD + SHIELD } pairs on Side A compared to the single pair on Side B.

These are the basic observations I personally work from, and the problem is that I just don’t see how these square with the number system suggested by the Masseys. Whatever the actual significance of the slashes, it doesn’t seem to me to coincide with any obvious difference in the language as used (because the PLUMED_HEAD + SHIELD pairs occur just about as often in slashed words as in unslashed ones): and (longhand) numbers are almost always a notably differently-structured part of any language.

For me, the big issue is that Side A is significantly more structured and repetitive than Side B. Also, its word lengths have much greater variance (i.e. Side A has both longer and shorter words than are found on Side B), and they use a different mix of shapes. Yet slashed words occur just as often on both sides. I just don’t get it, me.

I suspect that Side A and Side B use different kinds of language (ritual, performative, poetic, pragmatic, whatever) to assist very different functions: and probably courtly functions at that. But seeing it as a homogeneous number container for (say) Cretan tax accounting seems far too mundane. Bean counters never touched this artefact, no they didn’t! 🙂

Some of my pigeon questions answered…

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A few days ago I posted a list of open questions about the dead cipher pigeon, really as a way of externalizing the annoyance I felt from knowing so few basic facts. To my great delight, Mike Moor from Melbourne and (well-known military history buff) Christos T. stepped forward with a whole wheelbarrowful of answers. And here they are…

“Did any British pigeon handlers ever use “lib.” as an abbreviation?”

Mike Moor points out that the first message sent back on D-Day was by Reuters reporter Montague Taylor, attached to the eg of the war-seasoned (and subsequently Dickin-Medal-receiving!) carrier pigeon Gustav [NPS.42.31066]. At the bottom of the image (clearly on an RAF pigeon message pad), it says “Liberated 0830” (click to see the full message):-

“Why can’t I find a single other message written on the same printed pigeon service pad?”

For this, Mike Moor points to a message sent by Major General Roberts on a page talking about the Canadian armed forces’ involvement in World War Two. [Incidentally, the abortive Canadian raid on Dieppe was known as “Operation Rutter”, I wonder if Stu R knew that?] Even though the quality of the scan is frankly diabolical, it’s very much better than nothing at all, and tells us that this our pigeon message was (without any real doubt) an Army Pigeon Service message pad.

Mike also notes that this was an “Army Book 418B”, the updated version of the Army Book 418 used for pigeon messages in the First World War. It turns out that the National Army Museum near Sloane Square tube in London has an Army Book 418B in its collection described as “Army Book 418B, Pigeon Service Message Book, 1942”, accession number “1975-06-35”: it would be cool to ask the curators there to have a closer look.

“Was the pigeon message we have a hectograph or a carbon copy?”

Mike Moor notes “It is a carbon copy pad with 1 original retained in the book and 2 carbon copies made – which lines up with what you’d expect from the message i.e. 2 copies sent and the blue text of the cipher looks a lot like a carbon copy + black amendments by a second hand presumably prior to sending.” Excellent, thanks! 🙂

“When did Slidex change from having one letter per horizontal key slot to two letters per slot?”

The (plainly utterly indefatigable) Mike Moor points us to some December 1944 Slidex instructions available on Rob van Meel’s site (a copy will cost you two euros plus international postage from the Netherlands), by which time it had changed to two letters per key slot on the horizontal cursor. That narrows the range down dramatically to ‘sometime in 1944’… we’ll just have to keep digging to find out exactly when in 1944. At least this is a question that we can reasonably hope to get a solid answer on!

“When were Slidex Series B code cards introduced?”

In the Series A “RE No. 2” (Army Code No. 14070) Card 35 that I got from the excellent royalsignals.org.uk website, the three columns have had their shape changed to break up the columnar structure somewhat, which I believe may point to a rethink & upgrade of the Slidex code during WW2.

At the same time, another Series A card has two versions, one with an Army code and another with a different W.O. (War Office) code, which I suspect points to a post-WW2 handover from the Army to the War Office. But that’s as good an answer as this question has for now.

“Did Bletchley Park / GCHQ ever catalogue the tons of files brought back by the TICOM teams?”

Christos replies: “There are many TICOM file categories: I, IF, DF, M, D. Captured German documents had to be catalogued and then translated. This must have taken years. The question is whether there is a full list of those files. There is a DF list but I don’t know about any document covering the other files.”

Incidentally, p.38 of TICOM I-109 (a report by Lt Ludwig of Chi Stelle OB.d.L) says:

B. Slidex system.

Bigram substitution system.
In use in the army (front line units) and in air support networks (tentacle networks).
The system was known from the monitoring of exercises in Great Britain before the invastion, e.g. “Spartan”. The cryptanalytic detachments in army and GAF were able to get so much experience on these exercises that decoding worked well right at the start of the invasion.
Recovery was done in the army again at NAA St 5, in the GAF in 14/3 (W control 3).
Decoding was often done with so little delay that the messages could be dealt with like clear text in the evaluation.
The results were of more importance to the army than to the GAF, but theu provided the latter too with valuable indications, e.g. elucisation of the individual corps tentacle networks, reconnaissance operations (e.g. 400 and 414 Squadrons) etc.
The messages decoded daily were exchanged between Army and GAF in the form of written reports.