“This telegram must be closely paraphrased before being communicated to anyone”(history.stackexchange.com) |
“This telegram must be closely paraphrased before being communicated to anyone”(history.stackexchange.com) |
Boiled down to the very essence modern cryptography is: Using a secret seed plus a public seed, generate a long random number (of the same length as the message), then XOR that number with the message.
The hard part is generating that random number in such a way that you can not reverse the process and reclaim the secret seed.
Lookup "initialization vector" for more.
Lots of interesting stories in there, including when he suspected that Germans had captured all of their Dutch spies and were transmitting fake messages: real agents made mistakes when encoding due to stress, the Germans' fake encodings were all perfect.
It's called operation Mincemeat
Operation mincemeat wasn't a german officer, it wasn't anything about using a known plaintext to compare to coded messages, it wasn't pretending to be german documents, and it wasn't to help with cryptanalysis. About the only similarity is a dead body
> Michael was born in Aberbargoed in Monmouthshire in South Wales. Before leaving the town, he held part-time jobs as a gardener and labourer. His father Thomas, a coal miner, killed himself when Michael was 15, and his mother died when he was 31. Homeless, friendless, depressed, and with no money, Michael drifted to London where he lived on the streets.
> Michael was found in an abandoned warehouse close to King's Cross, seriously ill from ingesting rat poison that contained phosphorus. Two days later, he died at age 36 in St Pancras Hospital. His death may have been suicide, although he might have simply been hungry, as the poison he ingested was a paste smeared on bread crusts to attract rats.
> After being ingested, phosphide reacts with hydrochloric acid in the stomach, generating phosphine, a highly toxic gas. One of the symptoms of phosphine poisoning is pulmonary oedema, an accumulation of large amounts of liquid in the lungs, which would satisfy the need for a body that appeared to have died by drowning. Purchase explained, "This dose was not sufficient to kill him outright, and its only effect was to so impair the functioning of the liver that he died a little time afterwards". When Purchase obtained Michael's body, it was identified as being in suitable condition for a man who would appear to have floated ashore several days after having died at sea by hypothermia and drowning.
[1] https://en.wikipedia.org/wiki/William_Martin_(Royal_Marines_...
Wonder if we'll ever see it on a bond movie.
https://www.goodreads.com/book/show/7632329-operation-mincem...
Note that it is equally dangerous to send paraphrased messages using the same key (which is called sending messages "in depth"). This was used to crack the Lorenz ("Tunny") cipher. Interestingly Bletchley Park hadn't gotten their hands on a Lorenz machine, they cracked it based on speculation. And it lead to the development of the first tube computer, Collosus (which influenced the ENIAC). Nowadays we use nonces to avoid sending messages in depth, but nonce reuse can be similarly disastrous for systems like AES-GCM. For example there have been Bitcoin hardware wallets that reused nonces, allowing the private key to be extracted & the Bitcoin stolen. (To be clear, cryptocurrencies and AES-GCM are completely different systems that have this one property in common.)
https://en.wikipedia.org/wiki/Cryptanalysis_of_the_Lorenz_ci...
https://www.youtube.com/watch?v=Ou_9ntYRzzw [Computerphile, 16m]
As an aside does anyone know why it's called "in depth?" I'm guessing that it's related to Bletchley Park's penchant for naming things after fish? But possibly also their techniques that involved arranging messages together and sliding a stencil over them to visually spot patterns (so they're sort of overlayed)? I tried some casual searching but it's a very generic phrase and so difficult to search. It's defined in the The 1944 Bletchley Park Cryptographic Dictionary but it doesn't give an etymology.
https://www.codesandciphers.org.uk/documents/cryptdict/crypt... [Page 28]
As a child I learned about codes from a library book. Fascinated with one-time pads, I convinced a friend to try a correspondence. We exchanged a few messages, and then got bored, because the juice wasn’t worth the squeeze.
Which makes me wonder about people who work in secrets. Encrypted communications seem opposite of scientific communications. Secrets peeps seem prolly aligned to politics.
I recall that Ovaltine goes better with decoded messages.
https://arstechnica.com/information-technology/2017/04/this-...
And (more or less) that’s how the Enigma was cracked. Turns out starting weather report with ‘weather’ every single time is not a good idea.
1. https://archive.org/details/Fm3440.2BasicCryptAnalysis/mode/...
The suggestion that it may have been a striker from a bilingual - cyrillic typewriter that was mixed in is an interesting possibility; someone transcribing diplomatic telegrams in WWII may indeed have need of access to Cyrillic typewriters…
Randomizing/obfuscating the letter case might buy you a little time, though I think it's something else entirely here.
Enaqbzvmvat/boshfpngvat guR yRggRe pnfR zvtug ohl lbh n yvggyR gvzR, gubhtu V guvax vg'f fbzRguvat RyfR RagveRyl uReR.
Some of the E's look a little curly like epsilons but I'm guessing that may be an optical illusion.
But check out the 3 in "chancE3"
This bit has me perplexed. If you had a single message that you wanted to send multiple times in different forms, wouldn't compressing the message exponentially limit possible variation whereas expanding it would exponentially increase it? If you had to send the same message more than a couple of times I'd expect to see accidental duplicates pretty quickly if everyone had been instructed to reduce the message size.
I guess the idea is that if the message has been reduced in two different ways then you have to have removed some information about the original, whereas that's not a guarantee with two different expansions. But what I don't understand is that even if you have a pair of messages, decrypt one, and manage to reconstruct the original message, isn't the other still encrypted expansion still different to the original message? How does that help you decrypt the second one if you don't know which parts of the encrypted message represent the differences?
RadioNerds-TM 11-485 (PDF) (33.22 MB) 4
Internet Archive-US Army Cryptography Manuals Collection (see "TM_11-485.pdf")
That said, the nonce is still very important to avoid most key recovery attacks
I would imagine that the paraphrasing wouldn't be necessary in this case because it isn't quite as useful to compare two encrypted versions of the text versus an encrypted version and an unencrypted version (also I feel like there is some risk of a game of 'telephone' in that the meaning would change bit by bit to the point of having a different meaning over time, even if not intentionally)
If they have already gained the ability to decrypt today’s messages from station A in cipher A, and can therefore recover the plaintext of those messages; if they then find a message of the same length sent from station B in cipher B they can guess that that might be the same message, reverse engineer the key and maybe then decrypt all the messages being sent from station B in cipher B today.
Which makes me wonder: how many permutations of this rule could be conceived (and needed) that on the one hand would keep the point clear to the receiver, but on the other hand prevent such attacks?
In any case the best option is to not have (to repeat) this rule inside messages.
And the revolution is: It's really nice that nowadays we have telegrams that are more safe that they were during WW2 for example even with the military infrastructure available back then...
Or maybe we did have?
Not that this specific quirk is covered in the novel, but a reading of Neal Stephenson's Cryptonomicon would certainly help make one understand the kind of necessary paranoia that would lead to this kind of (important!) protective measure.
See also the use of the word “close” in literature, eg The Lord of the Rings “Gandalf is closer that ever”.
To keep it close or to hold it close meant to keep it secret.
I don't know if compression offers much protection against plaintext attacks.
This also makes me wonder how helpful AI is in such situations. AI is essential an extremely effective, lossy, compression algorithm.
> we show that it is possible to identify the phrases spoken within encrypted VoIP calls when the audio is encoded using variable bit rate codecs
https://crypto.stackexchange.com/a/2188
See also https://breachattack.com/ when the plaintext is partially attacker-controlled.
These paraphrasing instructions could be followed. But the paraphrasing could be done using some LLM. A sufficiently advanced adversary manages to invert the model somehow, and as a result can get the original plain text out of the paraphrased message, which lets them do a known-plaintext attack, get the key, and use it on other messages.
Sort of technobabble (is the idea of inverting an LLM nonsense?) but fun.
The computer museum also exhibits post-war computers all the way to modern machines. I'd say that museum is more for the geeks while the Bletchley Park museum is definitely worth a visit even if you're not into computers.
In the 1980s the Bletchley museum project put out a call for wartime electrical components so they could build their Colossus replica. My grandfather in the 1950s had made a chain of Christmas tree lights from govt issue tiny light lightbulbs he pinched from work. He painstakingly removed the nail polish he had painted them with 30 years earlier, and sent them to Bletchley. They used his family Christmas lightbulbs in the replica that is still there today.
I had the privilege of touring the museum with him in the 1990s. Also on that day I heard my grandmother’s stories of her time in the British Army during the war. That day was incredibly interesting and moving, and is an important memory for me.
Before there were general-purpose stored program digital computers, there were many special-purpose computing devices. They checked some, but not all, of those boxes.
- IBM had electronic arithmetic in test before WWII, but that went on hold during the war. Mechanical arithmetic worked fine, although slowly, and by 1939, Columbia University and IBM had something that looked vaguely like a programmable computer, built from IBM tabulator parts.
- The G.P.O. (the UK's post office and telephony provider) had been fooling around with electronic switching since 1934. That's where Tommy Flowers, who designed the electronics of Colossus, came from.[2] He had a tough life. After the war, he wanted to get into computers, but couldn't get funding because he couldn't talk about what he'd done for security reasons.
- Memory was the big problem. Colossus just had some registers, built from tubes. And plugboards, the ROM technology of the 1930s and 1940s. Useful memory devices were all post-war. Needed storage to get to stored program computers.
[1] https://www.researchgate.net/figure/Logical-architecture-of-...
The original definition of computer was basically a person wot computes (analyzes data and performs arithmetic and so on). That would have mostly involved pencil and paper, fag packets and napkins. IT co-opted the term for their devices, many years later.
What is your issue with Colossus performing automated computations/analysis given some inputs of some sort and hence being described as a computer?
One of the earliest modern day IT related truisms is "garbage in/garbage out" - that dates back to at least getting the clipper out on the cards. Can that notion be applied to Colossus or rather is Colossus the sort of device that gi/go might refer to?
What exactly is a computer?
The first machine to have it all was the Manchester Baby.[1] Now this really was sort of a descendant of Colossus, with some of the same people involved. It was mostly a test rig for the Williams Tube memory device.
Once there was something that could do the job of RAM, things took off quickly. Within two years there were quite a number of stored program electronic digital computer projects. Electronic arithmetic worked fine, but everybody had been stuck on the memory problem.
However, there is a connection between British electronics and ENIAC, which is the same, but happened in parallel, with the connection between earlier British electronics and Colossus.
During the decade before WWII, several fundamental circuits of digital electronics had been invented in UK, e.g. several kinds of electronic counters and the Schmitt trigger.
Those circuits have been invented mainly for use in experiments of nuclear physics and elementary particle physics, e.g. for counting events from radiation detectors, for which the existing mechanical counters and accumulators were too slow. The first digital electronic circuit, the Eccles-Jordan trigger, had also been invented by British physicists, but another decade earlier, at the end of WWI.
The British digital electronic circuits were a source of inspiration for the circuits used in the first (special-purpose) digital electronic computer, the Atanasoff-Berry Computer, which was built at Iowa State University immediately before WWII (the published British research papers were explicitly quoted in the ABC design documents).
In turn, the digital electronic circuits used in the Atanasoff-Berry Computer were a source of inspiration for those used in ENIAC, because a member of the Mauchly-Eckert team had visited the designers of ABC, inquiring about its components, even if later they did not credit any source of inspiration for the ENIAC design (the Mauchly-Eckert team founded a startup for making electronic computers, so they were wary of providing any information that would make their work appear as less original and not patentable and they were also extremely annoyed by the publication of the von Neumann report, which explained for everyone how to make an electronic computer, so it created very soon a great number of competitors for the company of Mauchly and Eckert).
1) it's just the typeface,
2) the teletype machine has unique letter so the machine it was received in is known (and hence which staff received it), reducing the ability to forge messages. Different machines could have had special letters, or all machines handling secrets had that particular "e"??
3) the machine broke and the repair shop only had a small-caps "E" handy.
With ENIAC, reconfiguring the computer for solving a new problem was done essentially in the same way as for an analog computer (or nowadays for an FPGA), by rewiring the connections between the arithmetic units, the storage registers and the control sequencers, so that ENIAC will solve the new problem when powered on.
The resemblance of ENIAC to an analog computer is not an accident, but its architecture has been conceived as an electronic substitute of the electro-mechanical analog computers known as "differential analyzers", which had been in widespread use both before WWII and during WWII, for computing solutions of systems of differential equations, which were found in various engineering problems, including in many of military importance.
On the other hand, Harvard Mark I had been inspired by Babbage's proposal for a digital computer with stored program, hence its architecture much closer to modern digital computers.
While ENIAC had an architecture inspired by the mechanical differential analyzers, for the schematics of its electronic arithmetic and register circuits it used some information from the designers of the earlier Atanasoff-Berry Computer, which was a special-purpose electronic computer for solving systems of linear algebraic equations, and which included even the first DRAM memory (the second DRAM memory will be the British Williams CRT).
I've never seen a corporate announcement whipsaw from technical incident report to tentative job offer to a threat paraphrasing the IRA before but I guess that's because I don't spend time in the cryptoasset community.
(My prior comment referenced Operation Mincemeat at the time of its reply, for those reading after the fact.)
I appreciate your edit that completely replaced the topic of your post; it is now much more interesting. But unfortunately, I could not edit my comment by the time I saw you had changed it
Seems like you just don’t like me. Sounds like motivated reasoning to me. But I thought you meant (my) other comment, not theirs. I think it’s possibly an issue with tone being hard to read in text. In any case, I try to add a correction instead of simply calling out mistakes, but you were right to say whatever you thought. I don’t mean to silence you, but your words had a chilling effect on my speech, so maybe give some reasoning and a correct answer next time instead of just calling someone wrong. Anyone can do that, and they too often do.
At least now I know it’s due to that argument being kind of a weak one. I thought they were concerned with the notes especially, which is why I included that reference because it specifically referred to notes. I think there may be other WW2 examples, but I couldn’t lay hand to them at the time.
> I appreciate your edit; it is now much more interesting.
I appreciate you saying that. I don’t mean to assume you don’t like me, but it seemed that way at the time you said it. Apologies for assuming, and for any offense caused.
Edit: For what it’s worth I didn’t downvote you either time, and in fact I upvoted the comment this one is in reply to.
What happened to them?
Other devices would calculate but not store instructions. The common ones you see are the fire directors on naval ships, which were analog “computers”, but single purpose.
There were many early machines which checked some, but not all, of those boxes. IBM's electronic multiplier. The Harvard Mark I. The SSEC. Colossus. Reservisor. Western Electric Plan 55-A. General Railway Signal's NX. The Bell Labs Complex Calculator. The Automatic Odds option for racetrack totalizators. The Mathatron. All of those machines did something that resembled computation.
The late 1940s, 1950s, and 1960s were full of strange special-purpose electronic digital hardware that didn't quite make it to a computer, because the parts count to get to a general purpose machine was too high.
Then came microprocessors, and it became cheaper to use general purpose microprocessors in dedicated applications. Now all those weird machines are forgotten.
Here's a brochure from Teleregister, which built custom special purpose systems for railroads, the military, airlines, stock exchanges, and such, from before WWII into the 1960s. There's no computer in those things, but a lot of electronics.
Mark I was an electro-mechanical computer, while SSEC was hybrid, including both electro-mechanical parts and parts with vacuum tubes. For a few years, IBM's SSEC was the world's most powerful "supercomputer", and it has solved a great number of diverse problems. SSEC had some advanced features that have been introduced in fully electronic computers only about a decade later, e.g. pipelined instruction execution (to compensate for its slow circuits).
What you mean is that none of your examples was a von Neumann computer, i.e. where there is a common memory for program storage and data storage, enabling the computer to create or modify programs by itself.
Obviously the common memory was an essential element for the evolution of electronic computers, enabling many features that were impossible when the programs were stored separately, on a ROM such as punched tape.
However, saying just "stored program" also covers the case when the program is stored in a separate ROM, as it may still be the case for a microcontroller, though nowadays most of them store the program in an alterable flash memory.
> (regular deception, no cryptographic purpose)
That is a very good distinction with a difference, and you were right to elucidate this; I only wish you had done it in your original reply to me. In any case, my stream of consciousness post above was in haste, and I think we were both editing at the time. I will try to post better. I wonder if folks are copy posting me? I honestly can’t say.