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Declassified Cold War code-breaking manual on solving 'impossible' puzzles
- zeeshanqureshi 5y agoGood to see [0] Polya's book mentioned (and linked) in the article. For anyone interested, it provides a pretty good general outline for problem solving techniques. [1] There's also a YouTube video of him explaining some of those methods. [0] https://math.hawaii.edu/home/pdf/putnam/PolyaHowToSolveIt.pdf https://math.hawaii.edu/home/pdf/putnam/PolyaHowToSolveIt.pd... [1] https://www.youtube.com/watch?v=h0gbw-Ur_do https://www.youtube.com/watch?v=h0gbw-Ur_do
- elahieh 5y agoYes, there are strong parallels between Polya's video and the "Cryptodiagnosis" chapter. The chapter is based on a monograph called "Ars Conjectandi" ("the art of conjecturing") and Polya's video theme is "first guess, then prove". "In all of one's endeavors, the successful cryptanalyst's precept should be kept foremost in mind: "Try the simplest thing first." It is surprising how often this admonishment is disregarded, to the later chagrin of the cryptosinner." -- Callimahos
- gjm11 5y agoIt might be worth mentioning that the title "Ars Conjectandi" is taken (clearly deliberately) from a much earlier (1713) work of the same title by Jacob Bernoulli, about combinatorics and probability. That title may well be a nod to an even earlier (1662) work called "Logica, sive Ars Cogitandi" -- Logic, or the Art of Thinking -- which was published anonymously and also includes some discussion of probability; probably substantial parts were written by none other than Blaise Pascal.
- rvba 5y agoMaybe I misunderstand something, but the article text says: > in 1992, the US Justice Department claimed releasing the third book could harm national security by revealing the NSA's "code-breaking prowess". It was finally released in December last year. When we move to the first page of the linked book it says: > This text constitutes the third in the series of six basic texts on the science of cryptanalytics. So there is still book 4, 5 an 6? (im probably on some list just for asking)
- fodmap 5y agohttps://en.wikipedia.org/wiki/Military_Cryptanalytics https://en.wikipedia.org/wiki/Military_Cryptanalytics
- TedDoesntTalk 5y ago> So there is still book 4, 5 an 6? Yes, and they are still classified (for now). Part III has been long sought after. Glad to see it’s out there (and that it’s release doesn’t jeopardize anything)
- shakna 5y ago> Part III has been long sought after. Glad to see it’s out there (and that it’s release doesn’t jeopardize anything) Well, 21% of it is released and out there. There's still 66 sections that were censored.
- jamiek88 5y agoOnly the first three were written.
- ganzuul 5y agoAre we guessing or knowing?
- elahieh 5y agoAuthor here - actually LDC died in October 1977, the same month this book came out. So there were more texts planned in the "Military Cryptanalytics" series, but they were never published.
- azalemeth 5y agoIt's worth saying that the book isn't entirely declassified. 18 out of 84 sections (including quite a few "Further remarks" or "Final remarks" sections) are completely whited out by the censor's box. Also, the actual PDF is here: https://www.governmentattic.org/39docs/NSAmilitaryCryptalyticsPt3_1977.pdf https://www.governmentattic.org/39docs/NSAmilitaryCryptalyti...
- ffhhj 5y ago> 6. Fundamental cryptanalytics in the solution of aperiodic systems. That section is white. Is there any information on cyphers that generate codes indistinguishable from absolute randomness based on the properties of entropy?
- thaumasiotes 5y agohttps://en.wikipedia.org/wiki/One-time_pad https://en.wikipedia.org/wiki/One-time_pad Note that for the code to be indistinguishable from absolute randomness, you need the key to be as long as the text.
- hanche 5y agoIn theory, yes. You might say that cryptography exists in the gap between the theoretically impossible and the practically achievable.
- qsort 5y agoThe only cypher that satisfies your request is "XOR the signal with noise, where the noise is a shared secret". Generally, you only require a weaker property: that a time-bounded attacker is unable to assert that the cyphertext is random with neglegible probability.
- anchpop 5y agoI think modular addition also has that property
- westcort 5y agoMy grandfather worked with Lambros and shared an amusing booklet from him called "A short list of even primes," which is a single digit: 2 (with a long and humorous introduction). It is not classified (obviously) and I will try to get around to sharing it on here at some point in the future.
- FredPret 5y agoIt’s the Cryptonomicon!
- grouphugs 5y agoi got attacked for years for making "puzzles," except i never made any puzzles, people are just fucking idiots
- ncmncm 5y agoIt is not widely reported that US cryptanalysts--in particular, a single husband-and-wife team, the Friedmans ACKed in the preface, and their students--decrypted Enigma messages by hand as readily as Bletchley Park with all its bombes, albeit in smaller amounts because they mostly intercepted South American traffic. They also decrypted all Japanese communications leading up to Dec 7, 1941, and after. Notably, the FBI never had any capacity for cryptanalysis. What they got, they got from the Friedmans. "Between Silk and Cyanide", by Leo Marks, is deeply enlightening, in particular about spycraft and its failings in Britain at the time.
- xendo 5y agoWhat’s even weirder is that breaking Enigma is often attributed to British cryptologists.
- ncmncm 5y agoThe Friedmans and the Poles did, independently. Brits only automated it, based on the Poles' work. British spycraft during WWII and well after was absolutely abysmal, with rare bright spots.
- ncmncm 5y agoAn excellent presentation on the work of the Friedmans is A Life in Code: https://bookshop.org/books/a-life-in-code-pioneer-cryptanalyst-elizebeth-smith-friedman/9781476669182 https://bookshop.org/books/a-life-in-code-pioneer-cryptanaly... but there are several other biographies. The government treated the Friedmans very badly considering how dependent it was on them. Ultimately it was only the Friedmans' sense of duty that prevented wholesale collapse of American cryptanalytic capability.
- pts_ 5y agoForwarded to AMZN and GOOGL.
- thrwn_frthr_awy 5y agoAre there any videos showing how these would be used in a real world situation?
- elahieh 5y agoYes! I linked to the recent Zodiac Killer cipher solution - https://youtu.be/iuNyQ44JYxM https://youtu.be/iuNyQ44JYxM - over many years, many people observed patterns in the cipher, and tried to determine how likely it was that each pattern was nonrandom. Eventually, they were inspired to try a particular combination of substitution and transposition based on a pattern people had observed at width 19. I think this observation was first made in 2015, and the cipher itself is from 1969. So in the "Cryptodiagnosis" chapter Callimahos says ... After finding a phenomenon - or what is thought to be a phenomenon - an evaluation should follow. It's not enough to say "I think the doublets are high." How many are there? Go count them. And, even more important, how many doublets are expected at random in a sample of this size? Then, the team showed how that last question could be answered for the Zodiac killer ciphers with Monte Carlo sampling (i.e. modern computer methods).