Pigeon bigram / Slidex update…

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Having got hold of a WW2 Slidex manual, I’m starting to see what a travesty of a coding system it was – and how a smart German decrypter could (with a bit of practice) decipher it almost in real time.

But Slidex was never intended as a highly secure coding system: it was only supposed to be a convenient way for people to discuss very short-term matters mostly in the clear over the radio or telephone, encoding any individual items or details that should not be overheard by the enemy. In fact because of its obvious lack of security, I don’t believe it was even classified as a “low grade” cipher.

Yet for a whole host of pragmatic reasons, it seems that Slidex was chosen to be used on D-Day for all non-machine cipher traffic. So if the pigeon cipher is in Slidex, can we crack it?

The first big problem we face is that “Slidex as described in the manual” and “Slidex as used in the field” seem to be quite different beasts. For example, though both employ a 12 x 17 (= 204-cell) table, manual-Slidex used a 12 letter horizontal key at the top, whereas field-Slidex (as evidenced by various pictures) seems to have used a pair of characters per key horizontal cursor cell, hence a 24 letter horizontal key. Similarly for the vertical key, manual-Slidex used only 17 characters whereas field-Slidex seems to have used all 26 alphabetic characters. So unless someone kindly comes forward and tells us how Slidex was actually used circa D-Day, we’re kind of stuck in a no-man’s land between manual-Slidex and field-Slidex, uselessly trying to guess what’s inside the Baggins’s nasty little pocket, yessss.

The second big problem is that unless something rather miraculous emerges from GCHQ’s archives, it now seems fairly unlikely we will ever get retrospective access to the daily keys used. Key pairs were tightly controlled and never used for more than 24 hours at a time (keys were normally changed over at midnight each day).

And yet… Slidex is designed to be quick and easy to use, with exactly the same code table and key pair used by both encoder and decoder. And in practice, all the symmetries and shortcuts that yield all that convenience also compromise the security to the point of uselessness.

For example, every 12-column-wide code table is arranged into three groups of four columns: and in each one I’ve seen, each group includes all 26 letters of the alphabet in alphabetic order, as well as a third of the numbers from 00 to 99, and a few SWITCH ON and SWITCH OFF cells. Moreover, in the code half of the cells, all the words are arranged in alphabetic order from top to bottom.

For example, the first four columns of the Royal Engineers Series A code table “No. 1” proceed like this:-

[?] 08  N  T
0/? G   16 24
OFF 09  O  25
00  H   P  U
A   I   17 26
01  1/? 18 ON
B   J   19 V
C   10  2  27
02  11  Q  W
D   K   20 X
03  12  R  28
E   13  S  29
04  L   ON 3
05  14  21 Y
06  M   22 Z
F   ON  T  30
07  15  23 31

(Original picture from Jerry Proc’s Slidex page, second image from bottom. Note there’s also a photo of an Op/Sigs code table there that closely follows the same kind of layout pattern).

Moreover, the German cryptologists interviewed by TICOM after the war noted that before September 1944, most people using Slidex tended to use the leftmost group of columns almost exclusively, which compromised yet further what was already a poor system. And the widespread habit of using Slidex for entire messages made the daily keys easier to get to rather than harder. What a mess!

And so if our mysterious dead pigeon message is in Slidex, all those flaws and poor enciphering practices might give us enough to decrypt it without a daily key, or even without a code table at all! After all, if the Germans could do it (albeit usually with more depth to work with), surely so can we?

Looking again at the bigram, if we precede each bigram with the number of times the first half of the pair occurs, I suspect we can predict fairly reliably which part of the message is in code and which part is in cipher:-

6HV 3PK 3DF 3NF 2JW 2YI 3DD 2CR
4QX
... 1SR 3DJ 6HF 3PG 1OV 3FN 4MI
4AP 1XP 4AB 1UZ 1WY 2YN 3PC
... ... ... ... ... ... ... 4MP
3NW 6HJ 4RZ 6HN 2LX 4KG 4ME 4MK
4KO 3NO 2IB 4AK 1EE 4QU 4AO 4TA
4RB 4QR 6HD 2JO 3FM 4TP 1ZE 6HL
4KX 3GH 4RG 3GH 4TJ 4RZ 2CQ 3FN
4KT 4QK 2LD 4TS 3GQ 2IR

Because so many single instance “1nn” pairs are clustered in the middle section (“1SR … 3PC”), I’m pretty sure that this is in code, and the last part (“4MP … 2IR”) is in cipher. The first part I’m unsure about.

If we now concentrate purely on the final section and look at the frequency counts and patterns there, plenty of other interesting things jump out:-

... ... ... ... ... ... ... 3MP
2NW 4HJ 4RZ 4HN 2LX 4KG 3ME 3MK
4KO 2NO 2IB 2AK 1EE 3QU 2AO 4TA
4RB 3QR 4HD 1JO 2FM 4TP 1ZE 4HL
4KX 3GH 4RG 3GH 4TJ 4RZ 2CQ 2FN
4KT 3QK 2LD 4TS 3GQ 2IR

From the way they cluster, I think that M and Q probably refer to the same column: and from the few single-instance “1nn” bigrams in there, I suspect that “EE” and “ZE” probably both encipher “E” (while “JO” could well encipher “T”).

What’s interesting is that it seems likely that the four columns encipher letters in alphabetic order: so (say) A-F, G-M, N-T, and T-Z in the case of the Royal Engineers code table #1 (there are a couple of extra E and T characters inserted around the table). It may be that this is enough for someone to try to solve this directly without any other information!

The Voynich Manuscript, Voynich theorists, and professional historians…

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In four words, the Voynich Manuscript is a puzzling old thing (and really, ain’t that the truth?). Filled with unknown plants, unrecognizable astrology & astronomy, and numerous drawings of small naked women, the fact that we also can’t read a single word of its ‘Voynichese’ text doubles or even triples its already top-end mystery. Basically, the Voynich Manuscript is to normal mysteries as a Scooby sandwich is to an M&S prawn mayonnaise sandwich.

People have their theories about it, of course. The last ripe strawberry of a mainstream Voynich theory came back in 2004 from academic Gordon Rugg, who declared that it was a hoax made using late 16th century cryptographic table-based trickery. Sadly 2009 saw an early 15th century radiocarbon dating of its vellum, which would seem to have made a fool of such fruity ingredients. Or if not a fool, then certainly a bit of a mess.

Despite almost-irreconcilable dating problems, numerous Voynich theories continue to find support from eager evangelists, angrily jabbing their fingers at any epistemological cracks they can see. The most notable get-out clause proposed is that some devious so-and-so could theoretically have used centuries-old vellum for <insert fiendishly clever reason here>, rather than some fresh stuff. This is indeed possible. But also, I think, rather ridiculous.

Why? Because it adds yet another layer of possible unlikeliness (for it is surely extraordinarily unlikely that someone back then would have such a modern sensibility about faking or hoaxing that they would knowingly simulate a century or more of codicological activity), without actually helping us to manage or even reduce any of the existing layers of actual unlikeliness.

Ironically, many such theorists prove anxious to invoke Occam’s Razor even as they propose overcomplex theories that sit at odds with the (admittedly somewhat fragmented) array of evidence we have. Incidentally, my own version is what I call “Occam’s Blunt Razor”: “hypotheses that make things more complicated should be tested last, if ever“.

For more than a decade, I’ve been watching such drearily unimpressive Voynich theories ping (usually only briefly, thank goodness) onto the world’s cultural radar. Most come across as little more than work-in-progress airport novella plots, but without the (apparently obligatory) interestingly-damaged-yet-thrustingly-squat-jawed protagonist to counterbalance the boredom of trawling through what passes for historical mystery research these days (i.e. the first half of Wikipedia entries).

And so I think it was something of a surprise when, back in 2006, I grew convinced that the Voynich Manuscript had been put together by the Italian architect Antonio Averlino (better known as Filarete), and even wrote a book about it (“The Curse of the Voynich”). But by taking that step, wasn’t I doing exactly the same thing as all those other Voynich wannabe theorists? Wasn’t I too putting out an overcomplex theory at odds with the evidence that signally failed to explain anything?

Well… no, not at all, I’d say. Averlino was the cherry on the dating cake I’d patiently built up over the years: the cake led me to the cherry, not the other way around. And that dating framework still stands – all the analysis I’ve carried out in the years since has remained strongly consistent with that framework.

Even so, I’m not wedded to Averlino: my guess is that you could probably construct a list of one or two hundred Quattrocento candidates nearly as good a match as him, and it could very well have been one of those. Yet what I am sure about is that when we ultimately find out the Voynich’s secrets, it will prove to be what I said: a mid-15th century European book of secrets; collected from a variety of sources on herbalism, astronomy, astrology, water and even machines; whose travelling author was linked directly to Milan, Florence, and Venice; and whose cipher was largely composed of 15th century scribal shorthand disguised as medieval scribal shapes (though with an annoying twist).

Averlino aside, please feel free to disagree with any of that… but if you do, be aware that you’ve got some important detail just plain wrong. 🙂

Perhaps the most disappointing thing about the Voynich Manuscript is that historians still skirt around it: yet in many ways, it offers the purest of codicological challenges ever devised. For without the contents of the text to help us (and a provenance that starts only in the 17th century, some 150 years or so after it was constructed), all a professional historian can rely on is a whole constellation of secondary clues. Surely this is the best gladiatorial arena ever offered?

I’ll happily help any historian who wants to take the mystery of the Voynich Manuscript on, 21st century style. Yet it would seem that few have the skills (and indeed the research cojones) to do ‘proper’ history any more, having lost them in the dense intertextuality of secondary research. Without close reading to back their judgment up, how many can build a historical case from a single, unreadable primary source?

You know, I still sometimes wonder what might have happened if, in the 1920s, John Matthews Manly and Edith Rickert had chosen not Chaucer as their über-subject matter but the Voynich Manuscript instead. As a team, they surely had more than enough cryptological and historical brains to come devilishly close to the answer. And yet… other times it seems to me that the Voynich offers a brutally nihilistic challenge to any generation of historians: for the techniques you have been taught may well be a hindrance rather than a help.

All in all, perhaps (capital-H) History is a thing you have to unlearn (if only partially) if you want to make sense of the Voynich Manuscript’s deep mystery – and that is a terrifically hazardous starting point for any quest. For that reason, it may well be something that no professional historian could ever afford to take on – for as Locard’s Exchange Principle would have it, every contact between things affects both parties. A historian might change Voynich thinking, but Voynich thinking might change the historian in the process… which might well be a risky exchange. Ho hum… 😐

What lurks in the basement?

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You don’t have to have the hundred eyes of Argus nor Watchman Ozymandias‘ wall of screens to notice that most stuff on the Internet is, errrm, a bit rubbish.

And yet… every once in a while, something unexpected pops up that (almost) makes it all worthwhile.

So, here’s a page that takes you on an unforgettable historical journey into a basement in Portland, Oregon. No ciphers, but great pictures, great text, great punchline… basically, I love it all. Bless you, Cabel, I hope you have a great 2013. 🙂

Bigrams in the pigeon cipher…

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I’ve been wondering whether the pigeon cipher might be based around bigrams, i.e. where you split the cipher into pairs. If you disregard what seems to be the ‘AOAKN’ key indicator at the start and end, there are two basic ways to split the message into pairs. What is immediately interesting is that if you start immediately after AOAKN, you get three repeated pairs in the message (rather than just one), and that four of those six repeats occur every other pair along a short stretch towards the end of the message.

AOAKN
HV PK DF NF JW YI DD CR QX SR DJ HF PG OV FN MI AP XP AB UZ WY
YN PC MP NW HJ RZ HN LX KG ME MK KO NO IB AK EE QU AO TA RB QR
HD JO FM TP ZE HL KX GH RG GH TJ RZ CQ FN KT QK LD TS GQ IR U
AOAKN

AOAK
NH VP KD FN FJ WY ID DC RQ XS RD JH FP GO VF NM IA PX PA BU ZW
YY NP CM PN WH JR ZH NL XK GM EM KK ON OI BA KE EQ UA OT AR BQ
RH DJ OF MT PZ EH LK XG HR GG HT JR ZC QF NK TQ KL DT SG QI RU
AOAKN

The WW2 “Slidex” code works by having a table of codes particular to each arm of the armed forces (i.e. Royal Engineers, Operations/Signals, etc) where each bigram pair encodes a particular word often used by that arm. To encipher numbers or words, you bracket them inside a pair of SWITCH ON and SWITCH OFF bigram codes (there are several of each), and pick bigrams that correspond to each letter or digit or digit pair.

Hence I strongly suspect that what we are looking at in “GH RG GH TJ RZ CQ FN” is a sequence of letters enciphered in the Slidex SWITCH mode, i.e. where each letter is enciphered as a bigram.

Unsurprisingly, I would really like to read the 1944 Revised Instructions for using the Slidex R/T Code, and to have copies of the various Slidex code sheets and coordinate offsets used by the Royal Engineers and Infantry Brigade on D/Day, as I suspect these will allow us to read this message (does anyone have copies of these I can see?) Fingers crossed!

The unfortunate life of the Army’s Cysquare cipher…

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When I was trawling through WW2 pigeon / cipher-related documents at the National Archives, I found a brief mention of a medium grade Army cipher called “Cysquare”. I half-remembered the name and that it was (unsurprisingly) a cy[pher] based around a square, but couldn’t remember the context at all.

However, when I later searched for it on the Internet, it all started to come back to me… because Cysquare had been devised by my cryptological hero, master codebreaker Brigadier John Tiltman (‘The Brig’). Very much as the NSA PDF paean to him would have it, few would disagree that Tiltman was indeed “A Giant Among Cryptanalysts“.

Tiltman himself wrote a short introduction to his Cysquare (recently declassified, though brutally redacted) called “A Cryptologic Fairy Tale“, on the basis (a) that he’d lost the original material and had had to make up some examples, and (b) that it had a happy ending (which I guess was that the Allied Forces won the war). Here’s how The Brig described it (though with a few linefeeds added to make it acceptable to our modern short attention spans):-

Sometime later in 1941 I produced the “Cysquare” which was accepted by the War Office as a low-echelon cipher to replace the “Stencil” cipher and issued to the Eighth Army in North Africa, Figures 8 and 9 [both redacted, *sigh*] give photographs of two pages of the printed instructions.

The grille has 676 (26 x 26) squares. Each column and each line contains 10 white (permitted) squares, with the exception of 3 “plus” lines containing 20 white squares each and 3 “minus” lines which contain no white squares at all. The key for the day consists of 26 letters of the alphabet in random order with the numbers from 1 to 26 written under them also in random order. For each message the operator selects a 4-letter indicator from a random list of such groups provided him for use in turn. The indicator in the case of the example given [but redacted] is GMBX. The numbers corresponding to this indicator are 11 19 20 7, i.e., position 11, line 19, column 20, taking out number 7. The grille could be used with any of its sides at the top. Position II indicates that the grille is used as shown with numbers 8 to 13 at the top.

The numerical key for the day is written from left to right at the top of the grille and from the bottom upwards on the left hand side. The plain text is written into the grille starting at the next white square after the square described by the line coordinate 19 and the column coordinate 20, using the elements of the key to define the corresponding lines and columns. If and when the operator reaches the last white square in the grille he proceeds from the top left-hand corner. He then takes out the columns of letters starting at the top of the grille and in the column designated by the taking out number, i.e., in this case 7.

The message is written out in 4-letter groups preceded by the 4 letter indicator and followed by the number of letters, the indicator repeated, and the time and date. No message of more than 220 letters was permitted. If a message handed in for transmission exceeded this length it had to be divided into parts, none of them exceeding 200 letters in length.

However, somewhat contrary to Tiltman’s story’s name, Cysquare itself didn’t really have a happy ending. For a start, a number of people thought that cryptanalysts such as Tiltman shouldn’t be messing about with making their own cipher systems, and so there was a certain amount of resistance to it from within, right from the beginning.

The second problem was to do with implementation: even though it relied on disposable pads containing pre-printed grilles, somewhere along the line someone had the bright stupid idea that they could economize by getting the Army cipher clerks in North Africa to reuse the pads, by writing messages in pencil and then erasing them with a rubber. However, before very long it became impossible to tell a blank square from a dark square – everything in the grille ended up fifty shades or grey (so to speak). Hence the cipher clerks refused to use the system, and it was quietly abandoned.

However, when Germans captured Cysquare pads and implementation notes, their cryptographers rather liked it. And so in 1944, a new system started to appear in German messages: the Rasterschlüssel (also known as RS44), a system derived directly from Tiltman’s Cysquare cipher. Of course, Tiltman quickly recognized it: and had the Germans not made some mistakes when designing their pads’ grille designs, they might have been extremely hard to decipher.

So… was Cysquare a success, or a disaster? It was certainly quite secure (if somewhat awkward to use): but in the end, it nearly gave Germany a cryptographic edge late in the war.

For fans of the pigeon cipher story, it seems unlikely that its message used Cysquare… and so the search for that goes on.

PS: there’s an 2004 article in Cryptologia by Michael J. Cowan called “Rasterschluessel 44 — The Epitome of Hand Field Ciphers“.

On irony, question marks, brackets, and the Voynich Manuscript…

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It may surprise you a little, but sometimes I do like to think about things which aren’t to do with cipher mysteries at all. Today I stumbled upon a short video on situational irony that, just like Alanis Morissette’s song “It’s Ironic”, professed to explain irony by example yet failed miserably. Having said that, perhaps the creator’s inability to explain irony despite setting out to do so is the best example of irony that could be given… but I’ll leave you to decide for yourself.

But that set me thinking about irony punctuation, specifically the reversed question mark ‘⸮’ which your browser may or may not support. And that set me thinking about the 16th century English origins of the modern question mark glyph ‘?’. And that set me thinking about the late mediaeval abbreviation for ‘quaestio’ (‘what’) i.e. ‘qo’ or ‘4o’, where (many typography historians believe) the ‘o’ subsequently migrated down beneath the ‘q’/’4’ to yield the modern question mark shape.

But that reminded me of a decade ago when I was tracing the origins of the ‘4o’ shape seen in the Voynich Manuscript: back then, I stumbled across some late 14th and early 15th century examples of ‘4o’ in legal documents, but have been unable to find any since. In retrospect, I think that what I was looking at were very probably examples of abbreviated ‘q[aesti]o’, i.e. prototypical question marks. In fact, this ‘4o’ glyph pair appears in a number of Northern Italian fifteenth century ciphers, particularly in Milan (but that’s another story).

Yet in Voynichese, the ‘4o’ shape almost always appears at the start of words (which isn’t where question marks go), and at the start of multiple adjacent words such as ‘qokedy qokedy’ etc (which is also not how question marks work). Hence I believe that what we are looking at in Voynichese’s ‘4o’ is a 14th century abbreviation-cum-shape being appropriated and put to some other confusing use within a non-obvious textual system, in just the same way that the Voynich’s ‘aiir’ / ‘aiiv’ family of shapes appears to be a 13th-14th century page numbering abbreviation-cum-shape being appropriated and put to some other confusing use within a non-obvious textual system.

If you can think of a better definition of cryptography, please let me know. 🙂

But while I was idly looking all this up, I noticed several mentions of medieval brackets: apparently, the widely used convention for these was to surround the contents with reversed brackets (i.e. back-to-front relative to modern brackets) and to underline the contents. So, whereas we would write (tum ti tum), a medieval scribe would write )tum ti tum( instead.

Wait just a minute, I thought, I’ve seen these early on in the Voynich Manuscript. Isn’t it the case that what researchers sometimes call “split gallows” enclosing text is simply visually hiding an upside-down medieval bracket set?

Just to be clear, here’s what I’m thinking:-

This visual trick only occurs right at the start of the manuscript (in fact, the above example is from f8v, on the back of the first bifolio). However, I suspect that splitting gallows in this way served to highlight the contents rather than to hide them, and so the encipherer then finessed the cipher system to use other (far less obvious) ways of achieving the same end through the rest of the document. Hence I believe that this was an early experiment in hiding the contents of the split gallows, which morphed into the far less visually obvious horizontal Neal keys (pairs of single-leg gallows, usually placed about 2/3rds of the way across the top line of a page or paragraph).

So… I started out trying to read about irony (and not do Voynich research), and ended up doing Voynich research after all. Is that ironic?

“Small explosion in Unicode factory, nobody hurt”… :-)

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Well, that was what I thought when I first saw the ciphertext in Part 2 Chapter 8 of “The Fates Unwind Infinity“, an online book detailing the anonymous author’s thoughts on a whole load of speculative-philosophy-style stuff (a great big hat-tip to Richard Greendale who passed a link to it my way, sorry it’s taken so long to post about it!) It’s the kind of obsessively intense book that seems to have been written in a three-day sleep-free trance: as far as I can tell, you might well need to enter a broadly similar state in order to make proper sense of it.

All the same, there’s something quaintly naive about the cipher alphabet used, in that it is made up of a load of rare characters all thrown together, like one of those abysmal Chinese emails where the proper character encoding has failed to arrive with the main text:-

˛¿?,.ç*ϕ , ¥ϕ’¡ˇ∆-.#-ϕπ¡q.µ•∆ˇ•.,*ϕ ,˚ç¿¡˛¡ç˚•ç¡çq˘.Ω’*ϕ¡Ô.çº-.¿˚¡∆ ,. ¥µç,.˛
¡*º•¡º•ˇ.˚’ϕ.ˇ¡π.ç∞¿µ¿.ç¡∆-.y¡,ˇç*•¡•˚.¿¡’•˛•¥ç¡çµ•¿,¿.ç.•Ωç¿ϕ¡’.ˇ˚.ºÔq.¿ π˘
¡-*˚∆.•*.•#-˛¿ˇ’ç.¥¡ˇ¿¡ π¿µ¡¿.ç∆’,Ω.,˚¡•˘.ˇ•∆.¿,˘¡˛¡ç.µ•¥.•*∞Ô¡º-∆¿˘ç˚ϕ-**.
¿¥¡ç.•.ç¡,.¿πˇ•.q’ˇ¡˘’,º-ˇ∆.•ºΩ.#¡•µ*˘.˚¥¿ç.-∆’¡˛ π˘.ç•¿*•,.ç.Ôqç,¿¡ç-
∆º.•˘’¿’•.ˇµ˛ç,ˇ˚ˇ∆¿¡*y,∞¿µ¿ç.˛Ωπ.-.,•¡’º•.ç∆ ¥ yç˚.ç¿,¿ç*Ô¡’•.πϕ-˘*•ç.•˛¡-.
¿,.µç•Ω¡¿.º-µˇ•.^ˇ˚∞¿ π*ç’∆•µ¡Ô˘ˇ.µ ¥*µ˚∆.¿¡Ω•.-ˇ¿•., πç˘º.-º*∆¡*˚•qÔ
¡’.˚’#¿˛*ˇ.˘ πçˇ•Ω¡¿¥ π.µˇ¿˘.∆º˚µç˚•.*’∆µ¡-˘¡¿-ç.,¿.¿*∆.,•¡¿ç π*.-.
¿˘,Ω’Ω.ç#ˇµ•’˚µÔ¡¿˛*¥¡’.¿∆ç π*.• ¥Ωq,˘∞.¿¿-*µ-*¥¡•µçµ¡•.,˛.¿µ∆˚,.º-
çµ πˇÔµ¡’µ.’•ϕ’ ¥-#y˚∆µº-¡ˇ¿µ•ç.µ¡˛.•˘π¡Ô,µ¡˚˚µ’µ,¿,∆-˛.Ωç•.¿¥µ.µçµ,-˘¿π
¡q•.Ô∆.˚ˇ-,µˇ’µç•’¿µ-˘¡ˇ¡µ˚.π∆.•∞-µç*Ô˛˘¿.Ω¡¥˚ˇ,•y.,∆•¡˛-¡*,¿π ,,µ.˛ç∆-
µ˚*˘•.’•.ˇ’-µ¿.ˇΩçyÔçˇ¡•˘¡˚*’,.∆º¿ç•ç π , ¥˘•¿.∞-¡˚˘*µ.Ω•.¿-˛qç,¡,•∆˛¿˘-
¿.•ˇ¥µçˇ,,’*ç’*˚ˇ¡∆ π ,*Ô¿’˛¿•.µy¡,畺Ωç-˚ ¥ ,ˇ•¿∆¿µ˛¡˘-¿•,¡*. π∆qç.º•,º*¿#
¡˛.,µ˚.¿çq˛çˇ,ç’¡µ•.¿’.,.qç˛¥∆硢*•,-∞•¿,˘¡qÔ¥.∆µ˛•.˚’¿,-∆^,•Ω
¿*çµπ纕q˘˚-˛¡ˇ-,,.µ#.’*ˇyº˛ϕ ,Ôˇç,˘¡∆q˘¥.¿’ç˛¿,•º*º•Ω¿µ˚,,硲.q¡¿∆π
¿∆µ.,祿-¡¿.˘.ç˛∆¡¿•¡¿çy-.¿º*.¿*ç∞¿∆’¡,µˇ•.’•,.ç¿-¿ˇº*ç*¡˚.’¥π.çºΩ¡*˘˛
¿∆.#.,•¡¿çµµ¿Ô∆•ç*∆-µº*qµ˚.-.¿Ω ,絲¿çˇ¥’¡µˇ•¡ˇ•., π.’ç¥*∆¿µyç.˚’µ¡¿,-
çº*ºµ.•˛.˚Ô¿µq¡ˇ.¥•˘.*,.¿-˚,µπ¡*.¿•µ¿µç˛µ-˚ç¥∞µç.•’¡ˇ,.-.’∆.Ωq’Ô¿•˚¡¿π.#,.
¥.¿˛¡,ç-˘*yµ*.¿•∆.ˇ,¿˚çº-˘¡˛,ç¿¥-*硵.,Ω•.˚ πçq¿•ˇç¿Ô.ˇ¡’Ωˇµ.*∆.ç’˛,¡¿,.
¥-.*˚’•.* π¡ºΩº.yç-.˛µ.¿¡ˇ¥µ,µç•,.˘.,.˛¡¿∆º.qç*ç¿˚-.•*.¿,˘ºç,ç¡∞.Ω’.ˇ˘ˇ
¡¿Ô∆.#ç˚•µçΩµç˛¿µµ ¥ˇ*ç¿ π*.*∆.•¿µ,ç-‘ç˚-*•¡-Ωπ ,¿¥¡ç∆˚¿.Ôq*¿¿∞.•ˇ.˛
¿çˇ¡q.¿,µ•’¿-,.˚¡’-¡*º•˛ç.ˇ,,¿.µç∆Ωπ.y¥µç˚*¡˛¿,¥,’¥¡∆çµ-ç•*.^Ô˚¿q•Ω.˛,˘µç
¥ˇµ-ˇ∞*.’ π∆¡’*˚q˘•ˇ.q∆¥µ¡˘.*¥Ô¿µ˛∆ç,.?µ˛¿.¡

Note that some of the shapes are in bold, though I haven’t transcribed these any differently (which may well be a mistake). Yet in fact, for all its typographical showiness, it turns out that this ciphertext uses only 27 different characters. Leaving ‘q’ and ‘y’ intact and replacing the rest with A-H and J-Z (I don’t like using ‘I’, it’s too easy to confuse it with ‘1’ and ‘l’), you get the rather more usable:

ABCDEFGHDJHKLMNOEPOHQLqERSNMSEDGHDTFBLALFTSFLFqUEZKGHLVEFWOEBTLNDEJRFDEA
LGWSLWSMETKHEMLQEFXBRBEFLNOEyLDMFGSLSTEBLKSASJFLFRSBDBEFESZFBHLKEMTEWVqEBQU
LOGTNESGESPOABMKFEJLMBLQBRLBEFNKDZEDTLSUEMSNEBDULALFERSJESGXVLWONBUFTHOGGE
BJLFESEFLDEBQMSEqKMLUKDWOMNESWZEPLSRGUETJBFEONKLAQUEFSBGSDEFEVqFDBLFO
NWESUKBKSEMRAFDMTMNBLGyDXBRBFEAZQEOEDSLKWSEFNJyFTEFBDBFGVLKSEQHOUGSFESALOE
BDERFSZLBEWORMSEYMTXBQGFKNSRLVUMERJGRTNEBLZSEOMBSEDQFUWEOWGNLGTSqV
LKETKPBAGMEUQFMSZLBJQERMBUENWTRFTSEGKNRLOULBOFEDBEBGNEDSLBFQGEOE
BUDZKZEFPMRSKTRVLBAGJLKEBNFQGESJZqDUXEBBOGROGJLSRFRLSEDAEBRNTDEWO
FRQMVRLKREKSHKJOPyTNRWOLMBRSFERLAESUQLVDRLTTRKRDBDNOAEZFSEBJRERFRDOUBQ
LqSEVNETMODRMKRFSKBROULMLRTEQNESXORFGVAUBEZLJTMDSyEDNSLAOLGDBQDDREAFNO
RTGUSEKSEMKORBEMZFyVFMLSULTGKDENWBFSFQDJUSBEXOLTUGREZSEBOAqFDLDSNABUO
BESMJRFMDDKGFKGTMLNQDGVBKABSERyLDFSWZFOTJDMSBNBRALUOBSDLGEQNqFEWSDWGBP
LAEDRTEBFqAFMDFKLRSEBKEDEqFAJNFMUGSDOXSBDULqVJENRASETKBDONYDSZ
BGFRQFWSqUTOALMODDERPEKGMyWAHDVMFDULNqUJEBKFABDSWGWSZBRTDDFMAEqLBNQ
BNREDFJBOLBEUEFANLBSLBFyOEBWGEBGFXBNKLDRMSEKSDEFBOBMWGFGLTEKJQEFWZLGUA
BNEPEDSLBFRRBVNSFGNORWGqRTEOEBZDFRABFMJKLRMSLMSEDQEKFJGNBRyFETKRLBDO
FWGWRESAETVBRqLMEJSUEGDEBOTDRQLGEBSRBRFAROTFJXRFESKLMDEOEKNEZqKVBSTLBQEPDE
JEBALDFOUGyRGEBSNEMDBTFWOULADFBJOGFLREDZSETQFqBSMFBVEMLKZMREGNEFKADLBDE
JOEGTKSEGQLWZWEyFOEAREBLMJRDRFSDEUEDEALBNWEqFGFBTOESGEBDUWFDFLXEZKEMUM
LBVNEPFTSRFZRFABRRJMGFBQGEGNESBRDFOKFTOGSLOZQDBJLFNTBEVqGBBXESMEA
BFMLqEBDRSKBODETLKOLGWSAFEMDDBERFNZQEyJRFTGLABDJDKJLNFROFSGEYVTBqSZEADURF
JMROMXGEKQNLKGTqUSMEqNJRLUEGJVBRANFDECRABEL

However, despite the promising-looking frequency counts, I haven’t yet had any luck cracking this as a monoalphabetic substitution cipher. The Friedman index of coincidence for this is 1.52 (slightly too low for English), which makes me strongly suspect that some punctuation is being enciphered here. Yet the commonest letter (‘E’) seems too frequent to be a plaintext ‘e’, and it doesn’t seem to encipher a space either.

As far as n-grams go, repeated 2-grams include:-
* EB (28 instances)
* SE (23)
* DE (19)
* ES (17)
* RF LB EF (16)
* ED (15)
* FE BR (14)
* BE NE BD (13)
* etc

Repeated 3-grams include:-
* GEB OEB MSE (5 instances)
* ETK EOE EBD SED KSE NES FES (4)
* LQE LBF DEJ OUL RMS RTE RFS QGE BEF BDU LBE GNE DBE EDS EBL DUL DEF DSL EKS EQN SDE GWS FTS ESG ERF JRF LKE SME SLB SEB ZSE SGE (3)
* etc

Sadly CrypTool-online only goes up to length-3 n-grams, as I suspect there may be some interesting 4-grams and 5-grams in there. An exercise for the reader! 😉

I don’t know what to make of this: when I first transcribed it, I really thought the answer would just pop out, but I haven’t had any luck with it so far… so I think I’m missing a trick. Any thoughts, codebreakers? 🙂

“The Curse of the Voynich”, now back on sale…

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Just a quick note to let you know that a freshly printed boxful of my book “The Curse of the Voynich” arrived here today, and with shinier covers than ever. 🙂 It is, of course, a perfect last-minute cipher-mystery-related Christmas present (for others or indeed for yourself), so feel free to order a copy (click on the appropriate PayPal-linked Buy Now button at the top there, and off you go).

If you don’t know about my take on the Voynich Manuscript, I’ve posted a 1000-word summary of the book here, part of which was covered in the National Geographic Ancient X-Files half-episode you may have seen (and which YouTube has now taken down). What I like best about “Curse” is that for all the potshots people have tried to take at it, it’s all basically still standing, which – considering that this is a highly-contested field where a typical Voynich theory has a shelf-life of a few days at most – is pretty good going, I think. 🙂

As always, I sign all copies bought direct from the Compelling Press site, and offer the option of adding an anagrammatic dedication at the front: so if your name was (for example) “Leonardo da Vinci”, you could have your copy dedicated to “Vindaloo and Rice” (which remains one of the best anagrams ever, however much you happen to like “Invalided Racoon”).

Incidentally, of all the other books on the Voynich Manuscript out there, I’d strongly recommend Mary D’Imperio’s classic (1976) “An Elegant Enigma”, which is now freely downloadable from the NSA as a PDF. Anyone with an interest in the Voynich Manuscript should read this – even if it is a little bit dated in places, D’Imperio does cover a lot of ground.

Dead WW2 pigeon cipher cracked with WW1 codebook (says the Mail)… errr, really?

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According to today’s Mail on Sunday, Canadian expert Gord Young has cracked most of the dead WW2’s pigeon’s cipher message using a WWI Royal Artillery codebook. It’s not a big old message, so let’s line up the decrypt for ourselves, shall we?

What is immediately clear is that
* The decrypt is done down columns of groups, not along rows of letters (…which isn’t how it was usually done at all)
* Each five-letter cipher group is presumed to be a completely independent initial-based sentence (…which isn’t etc)
* Each independent sentence’s decryption is guessed at somewhat hopefully (…which isn’t etc)
* “J” mostly codes for “J[erry]”
* “Q” pretty much always codes for “[Head]q[uarters]”
* “P” mostly codes for “P[anzers]” (a word which was only coined in about 1940, awkwardly for the WW1 codebook idea)
* Eight of the five-letter cipher groups are skipped because they don’t fit this (already very loose) pattern. (What?)

(1)AOAKN (?)HVPKD (10)FNFJ[W/U] (?)YIDDC
(2)RQXSR (7)DJHFP (11)GOVFN (15)MIAPX
(3)PABUZ (?)WYYNP (12)CMPNW (16)HJRZH
(?)NLXKG (?)MEMKK (?)ONOIB (17)A[K/R/H]EEQ
(4)UAOTA (8)RBQRH (?)DJOFM (18)TPZEH
(5)LKXGH (?)RGGHT (13)JRZCQ (19)FNKTQ
(6)KLDTS (9)GQIR[U/W] (14)AOAKN

(1) AOAKN – Artillery observer at ‘K’ Sector, Normandy.
(2) RQXSR – Requested headquarters supplement report.
(3) PABUZ – Panzer attack – blitz.
(4) UAOTA – West Artillery Observer Tracking Attack.
(5) LKXGH – Lt Knows extra guns are here.
(6) KLDTS – Know where local dispatch station is.
(7) DJHFP – Determined where Jerry’s headquarters front posts.
(8) RBQRH – Right battery headquarters right here.
(9) GQIR[U/W] – Found headquarters infantry right here.
(10) FNFJ[W/U] – Final note, confirming, found Jerry’s whereabouts.
(11) GOVFN – Go over field notes.
(12) CMPNW – Counter measures against Panzers not working.
(13) JRZCQ – Jerry’s right battery central headquarters here.
(14) AOAKN – Artillery observer at ‘K’ sector Normandy.
(15) MIAPX – Mortar, infantry attack panzers.
(16) HJRZH – Hit Jerry’s Right or Reserve Battery Here.
(17) A[K/R/H]EEQ – Already know electrical engineers headquarters.
(18) TPZEH – Troops, panzers, batteries, engineers, here.
(19) FNKTQ – Final note known to headquarters.

Sorry, Mail editors, but you’ve landed yourself a bit of a dud story here. If there is something good about this theory (and I for one haven’t found it yet), it’s hidden beneath a tangled mess of obviously wrong & over-interpretative nonsense, the kind of foolishly hopeful non-decrypticity David Kahn termed “enigmatology”. Ohhhhh dearrrrry me. 🙁

2012 Advent Calendar Day #10: Book theft with climbing rope…

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Earlier this year I found a true story about an obsessed book thief and a high-up monastery that I loved & wanted to share: all of which (in a funny sort of way) brought to mind Allison Hoover Bartlett’s very enjoyable (2009) “The Man Who Loved Books Too Much“, which would be a nice Christmas gift for a bibliophile (I already have a copy, so it’ll just have to be Belgian chocolates again this year, *sigh*).

It’s a tale of how local teacher Stanislas Gosse found an old map in the Strasbourg city archives showing a nearby monastery’s secret stairways and passages, and then decided to go exploring. He ended up in an room in the library locked to the outside, and impulsively decided to take some books and carry them down the mountain – he ended up with a thousand books in his flat before finally getting caught. Of course, he never sold any, it was more a private obsession that grew for the thrill of it than for anything as sordid as financial gain, I suspect. Anyway, a great little story… enjoy! 🙂