I forget who told me this story, but at some point the British tried a crazy known-plaintext attack by planting handwritten notes in dead German soldiers’ pockets that contained an “important message” to be sent, and then in the following days they would attempt to decrypt enigma communications against the known plaintext.
Few years ago I read 'Between Silk and Cyanide': Britain's Wartime Spies and Saboteurs', the autobiography of Leo Marks who worked in the British Special Operations Executive. He designed cryptography for agents behind enemy lines (thus the title: you could print one time pads on silk, and silk was harder to discover during pat-downs than paper).
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.
that's... not what gp was talking about. Why are so many people jumping in with this mistake?
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
The story of the man[1] whose body was used to fool German intelligence during Operation Mincemeat is quite tragic:
> 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.
> Part of the wider Operation Barclay, Mincemeat was based on the 1939 Trout memo, written by Rear Admiral John Godfrey, the director of the Naval Intelligence Division, and his personal assistant, Lieutenant Commander Ian Fleming
That's cool, I hadn't heard of that. I did hear that they made the mistake of repeating certain phrases, including signing everything with a "heil hitler", but also something about the weather forecast starting the same way every time.
ETA: Note that I appear to have been mistaken about the connection to ENIAC.
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.)
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.
I visited Bletchley Park museum this summer when in London. Can recommend and it's also really easy to get there; just a 50 minute train ride from London Euston station, and 5 minute walk to the museum. Entire family enjoyed the museum (have two teenage kids). There is also the "National Museum of Computing" located next to it which contains the Bombe, Collosus and related equipment. As I understand it most (or all?) of the original hardware was destroyed after the war to avoid leaking any information about the British code breaking skills. Thus, the machines on display are replicas, but should be fully working.
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.
A personal Bletchley Park anecdote: my grandfather, an electrical engineer, staffed a radio listening station during the war, and every evening a motorcycle dispatch rider would take the day’s intercepts away to a secret location. It was more than 20 years before my grandfather figured out they went to Bletchley.
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.
I recall from my own visit that the electrical transformers are supposedly original. So, the National Museum of Computing justifies calling its Colossus a rebuild rather than a replica, since it is made with some original parts.
As I point out now and then, Colossus was not a computer. It was a key-tester, like a Bitcoin miner. Here's the block diagram of Colossus.[1]
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.
"Colossus was not a computer. It was a key-tester,"
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?
This is the first I’ve heard of Colossus influencing the ENIAC. I was under the impression that Colossus was so secret that ENIAC was designed independently and (falsely) touted as the first tube computer prior to Colossus’ existence being declassified. I’m not sure if I’m misremembering that though.
The ENIAC seems to be the first general purpose electronic digital computer. It wasn't stored program, though - no good memory devices. Plugboards and lots of rotary switches. Took hours to load a new program. Unrelated to Colossus.
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).
I think you're right, my mistake. I didn't find anything definitive but given they were developed around the same time by (on cursory inspection) different people and that Colossus was as secret as you say (it wasn't declassified until the 70s), it does seem unlikely. I thought that had been mentioned in a Computerphile/Numberphile video on the topic but I must be mistaken.
An interesting quirk in Ethereum is that a contract address is determined by deployer address + nonce. So, you can send ETH to a contract that does not exist, then later deploy a contract there and recover it.
It is also the same address on many forks of Ethereum, which has led to some strange circumstances when Optimism sent tens of millions of dollars to a smart contract address on the wrong blockchain, and a hacker was able to create a smart contract they controlled using the same address on the blockchain it was accidentally sent to and steal the funds.
If you model the distribution of messages as a tree from sender to recipients, the key's reuse across messages could be measured as "depth" in a structural sense.
My assumption about “in depth” is that it comes from the idea of giving the adversary a greater depth of material to work with. I don’t have anything to back this up.
Interesting. I liked the explanations in the accepted answer. This rule especially,“Never repeat in the clear the identical text of a message once sent in cryptographic form, or repeat in cryptographic form the text of a message once sent in the clear.”
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.
Do you remember the book? I remember loving Alvin's Secret Code, which was on the bookshelf in my fourth-grade classroom where I sat in the back to be near the bookshelf...
Sorry, no. But it would have been a 70s or 80s publication. I recall there were several Cold War code stories, so it might have been on this subject. Like popular history stories, one after the other—you thought that was crazy? Check out this hollow nickel! But all very serious like.
> Never repeat in the clear the identical text of a message once sent in cryptographic form, or repeat in cryptographic form the text of a message once sent in the clear
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.
Standard US cryptographic protocol during the same time period was to begin and end every message with a few random words specifically to thwart such attacks.
Seems like an interesting conundrum. If you encrypt all transmissions, you end up having a lot of boring repetition, like weather and sign offs to just fill space. But if you don't encrypt the boring stuff, then the transmission itself is a nice signal of something interesting about to happen. But if you try to just pad with completely random noise, the other end might worry they've decoded something wrong and ask for a new cipher pad increasing the chance of interception. So maybe they should have tried to find something almost random but with known structure instead of sending the weather? Seems similar to how we now know that choosing a random password from the dictionary adds encoding redundancy without reducing security. Or similar to the goal of getting ordinary people to use Tor for ordinary things?
For people interested in these kinds of things, there is a very interesting military manual on the internet archives which goes though all the various pre computer pen and paper ciphers and how to crack them.
Oh that makes sense. I assumed wrong that it was going to be about prisoners sending secret messages in their letters home, and the guards wanting to scramble those out.
This is a familiar concept from reading about WW2 spy stuff (Between Silk and Cyanide, for example, which I highly recommend). But what REALLY intrigues me is the typeface of the letter with its upper-case 'E' used in place of 'e'. What's up with that?
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…
Interesting idea, but both the Cyrillic and Greek capital E would be a similar size to the Latin capital E. And in both alphabets the lower case e doesn't look like a smaller capital E. It's е/ε.
Might be unrelated in this example, but when a message is written in a lazy ROT13-like cypher, the letter e becomes a notorious rat that allows anyone to break the entire thing in very little time.
Randomizing/obfuscating the letter case might buy you a little time, though I think it's something else entirely here.
Zvtug oR haeRyngRq va guvf RknzcyR, ohg juRa n zRffntR vf jevggRa va n ynml EBG13-yvxR plcuRe, guR yRggRe R oRpbzRf n abgbevbhf eng gung nyybjf nalbaR gb oeRnx guR RagveR guvat va iRel yvggyR gvzR.
Enaqbzvmvat/boshfpngvat guR yRggRe pnfR zvtug ohl lbh n yvggyR gvzR, gubhtu V guvax vg'f fbzRguvat RyfR RagveRyl uReR.
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.
The repeating of the message is how the Allies initially broke the Geheimskreiber a much more secure encryption machine to Enigma that used XOR and rotors:
This is interesting in itself because should the Germans have got a hold of this widespread memo, then it might have tipped them off as to how their Enigma system might be attacked.
Readit News
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.
Deleted Comment
It's called operation Mincemeat
https://pca.st/podcast/0d412ec0-af39-0139-c19f-0acc26574db2
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
Deleted Comment
> 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]
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-...
[2] https://en.wikipedia.org/wiki/Tommy_Flowers
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.
[1] https://en.wikipedia.org/wiki/Manchester_Baby
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).
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…
Deleted Comment
Dead Comment
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"
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.
https://en.wikipedia.org/wiki/Siemens_and_Halske_T52