[HN Gopher] Declassified Cold War code-breaking manual on solvin...
       ___________________________________________________________________
        
       Declassified Cold War code-breaking manual on solving 'impossible'
       puzzles
        
       Author : sandebert
       Score  : 110 points
       Date   : 2021-06-05 08:56 UTC (14 hours ago)
        
 (HTM) web link (phys.org)
 (TXT) w3m dump (phys.org)
        
       | zeeshanqureshi wrote:
       | Good 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.pd...
       | 
       | [1] https://www.youtube.com/watch?v=h0gbw-Ur_do
        
       | azalemeth wrote:
       | It'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/NSAmilitaryCryptalyti...
        
         | ffhhj wrote:
         | > 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?
        
           | qsort wrote:
           | The 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.
        
           | thaumasiotes wrote:
           | 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.
        
       | westcort wrote:
       | My 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.
        
       | rvba wrote:
       | Maybe 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 wrote:
         | https://en.wikipedia.org/wiki/Military_Cryptanalytics
        
         | TedDoesntTalk wrote:
         | > 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)
        
       | FredPret wrote:
       | It's the Cryptonomicon!
        
       ___________________________________________________________________
       (page generated 2021-06-05 23:00 UTC)