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John Nash's Declassified 1955 Letter To the NSA 93

Posted by Soulskill
from the somebody-borrowed-doc-brown's-delorean dept.
An anonymous reader writes "In 1955, John Nash sent an amazing letter (PDF) to the NSA in order to support an encryption design that he suggested. In it, he anticipates computational complexity theory as well as modern cryptography. He also proposes that the security of encryption can be based on computational hardness and makes the distinction between polynomial time and exponential time: 'So a logical way to classify enciphering processes is by the way in which the computation length for the computation of the key increases with increasing length of the key. This is at best exponential and at worst probably at most a relatively small power of r, ar^2 or ar^3, as in substitution ciphers.'"
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John Nash's Declassified 1955 Letter To the NSA

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  • by Frosty Piss (770223) * on Saturday February 18, 2012 @12:20PM (#39086205)

    Hereâ(TM)s some linkys to the actual NSA website pages that talk about this:

    http://www.nsa.gov/public_info/press_room/2012/nash_exhibit.shtml [nsa.gov]

    http://www.nsa.gov/public_info/_files/nash_letters/nash_letters1.pdf [nsa.gov]

    • by Anonymous Coward

      I couldn't find "Hereâ" listed in any trademark office. Can you give a reference that it is a trademarked term?

  • by BoRegardless (721219) on Saturday February 18, 2012 @12:38PM (#39086333)

    I think overtly creative people get to be that way partly because they are not "normal". It is their gift or mindset to be able to see, conjecture and analyze what others can not fathom.

    Yet we tend to shy away from anyone who is "not normal". I am glad Mr. Nash has been able to proceed in his career in spite of his problems. I hope his story gives others with problems some inspiration.

    • by Anonymous Coward

      To find clever is to lose a little sanity.

    • Re: (Score:2, Informative)

      by Anonymous Coward

      "Yet we tend to shy away from anyone who is "not normal"."

      I believe he was exposed to the invisible realities of evil. Don't watch the movie, read the book, read about his life experiences and about the men with "red" ties.

      There is more to the disease than most know. It's a revealing of the puppets behind this reality, they must be run all the way to hell by the power of Yahweh, and they run when you take the power God offers you.

      The movie glossed over the interesting elements of his life and his disease.

      Op

    • Amen Brother!

    • by rssrss (686344) on Saturday February 18, 2012 @02:51PM (#39087211)

      Mr. Nash's creativity and his illness were two different things. There are many people with the same illness that he had, which appeared to be a form of schizophrenia, who have no creative accomplishments, just delusions, illness, and death.

      Mr. Nash spent many years in the grip of delusions and manias. He was, after a very long time able to achieve the ability to live with his family, interact with his community, and work on Mathematics.

      That he was able to do so speaks well of both his family and his community. Most people with his illness do not. They wind up institutionalized, or, what is worse, homeless, uncared for, subject to substance abuse and other illnesses, and premature death.

      • by Anonymous Coward

        ...

        That he was able to do so speaks well of both his family and his community. Most people with his illness do not. They wind up institutionalized, or, what is worse, homeless, uncared for, subject to substance abuse and other illnesses, and premature death.

        They used to wind up institutionalized. The Reagan administration undid that, so now they just wind up homeless, uncared for, subject to substance abuse and other illnesses.

        • To quibble, appropriations come from Congress, not the president. Besides, in the U.S., there is more than one level of government. If the feds drop the ball, states are welcome to pick it up.

          • by nobodie (1555367)

            The history of what happened is more complex. Jimmy Carter tried to relieve some of the problems with the institutions by providing government support for some less needy cases to return home or to live on their own with social workers supporting them and their families. The idea was that it was cheaper to do this than to keep them in an institution, which was true but the other part was that the institutions were not helping the mentally ill to live the best life they could. They were just warehoused becau

        • by rssrss (686344)

          De-institutionalization occurred in the 1950s and 60s, by the time of the Regan administration in the 1980s, it was the norm.

      • Re: (Score:3, Informative)

        by stevedog (1867864)
        You are right in the sense he should not be "congratulated" for his illness. However, I would take caution before labeling the creativity and the illness as "true and true, but unrelated." By modern criteria, he very well may have had bipolar disorder with psychotic features (he did get diagnosed with schizophrenia, but back then so did everyone else who "acted crazy" -- delusions and psychosis fairly commonly accompany severe bipolar as we diagnose it nowadays). If so, then actually his periods of brillian
    • by flowwolf (1824892)
      his problems? I would call it more of a gift.
  • by CurryCamel (2265886) on Saturday February 18, 2012 @12:47PM (#39086365) Journal

    Reading Nash's letters makes me realize how much better presentation medium powerpoint is.
    And also how much junk is made to sound nice, just with a nice presentation.

  • by measure (832061) on Saturday February 18, 2012 @01:13PM (#39086551)
    After Nash invents modern cryptography, explains it quite eloquently in a few pages of hand written notes, and designs and builds an electronic machine that automatically encrypts / decrypts the messages. He is then sent form letter rejection by the government: "It has been found that cryptographic principles involved in your system, although ingenous, do not meet the necessary requirements for official application."
    • by Hentes (2461350) on Saturday February 18, 2012 @01:32PM (#39086647)

      They hint that they have found a weakness in it, but for some reason they don't disclose it. It might be the case that the NSA wanted to keep it secret, just like the British did [wikipedia.org].

      • by interval1066 (668936) on Saturday February 18, 2012 @02:05PM (#39086893) Homepage Journal
        Or, they simply wanted to butter him up and keep him quiet because the presiding industrial defence complex entities at the time (Westinghouse, GE, Hughes, Bell Telephone (or later, AT&T), etc.) already had inferior, but completed cryptographic solutions ready to go. How many times has the Fed been handed elegant solutions to problems only to pass them by for fixes given to them by men from the old boy's network?
        • by iluvcapra (782887)

          You're right, I can't imagine why they'd work with a vendor with a three-decade track record of on time deliveries and at-cost wartime contracting, when an academic and known schizophrenic with no manufacturing or operational experience was available.

          • You're completely glossing over my point; how many times has the government spent millions on massive, bloated, unworkable solutions after they get handed an elegant solution? I suspect the cases are in the thousands. Thanks for being so cavalier with MY money.
            • I suspect the cases are in the thousands.

              Ah, well. As long as you have hard numbers, then.

              Thanks for being so cavalier with MY money.

              You would, of course, be saying the exact same damn thing if the government were spending millions of dollars on elegant-sounding but ultimately impractical or unworkable solutions offered by academic geniuses with no experience in government or project management.

              • Ah, well. As long as you have hard numbers, then.

                You've never heard the reports of government waste in the media? I find that difficult to believe.

                You would, of course, be saying the exact same damn thing if the government were spending millions of dollars on elegant-sounding but ultimately impractical or unworkable solutions offered by academic geniuses with no experience in government or project management.

                I find that many government geniuses have no experience in government or project management. Glad you seem to have gotten so lucky.

          • Hmm, and totally unrelated, nobody's using Hash127 [cr.yp.to] either ...

    • by FrootLoops (1817694) on Saturday February 18, 2012 @03:43PM (#39087581)

      Actually I was surprised by how much interest the NSA showed. Here was a young (~27) assistant professor of math writing to the government largely out of the blue. Nash himself was relatively insecure in his reputation, at least to this audience:

      "I hope my handwriting, etc. do not give the impression I am just a crank or circle-squarer. My position here is Assist. Prof. of math. My best known work is in game theory (reprint sent separately)."

      Even though he's insecure, he still chose to hand-write his letters sloppily with relatively poor penmanship and words crossed out. Still, the NSA dutifully corresponded with him and analyzed his machine, concluding

      "[it] has many of the desirable features of a good auto-key system; but it affords only limited security, and requires a comparatively large amount of equipment. The principle would not be used alone in its present form and suitable modification or extension is considered unlikely, unless it could be used in conjunction with other good auto-key principles."

      The letters certainly don't give me the impression of someone who is serious about making a working cypher machine. He's pretty clearly just dabbling in cryptography because it's a nice mental game for him to play. That doesn't necessarily mean his ideas should be ignored, and (somewhat surprisingly) the NSA didn't ignore them.

    • dude, they are payed to be secretive. they are the big brother of the CIA. hell they probably used to spy on the CIA.

      they probably took his theories and used them (if they didnt already have people who had come to similar conclusions working for them already).

  • by johnwbyrd (251699) on Saturday February 18, 2012 @03:37PM (#39087537) Homepage

    As I read the correspondence I tried to put myself in the position of Dr. Campaigne, and tried to figure out whether what Nash was saying made any sense. I confess that Nash's presentational style made me feel as though I was reading what Nash himself referred to as "a crank or circle-squarer". The core of Nash's invention is a squiggly, messy node graph of colored lines demonstrating a manually obfuscated binary function. But the importance of his communication is the importance of P vs. NP functions, which Nash communicated very very obliquely. Nash's Unabomber handwritten font didn't help him either.

    I feel bad that I would have made the same mistake that Campaigne did. But I think nearly anyone would have.

    • by Tablizer (95088)

      Nash's Unabomber handwritten font didn't help him either.

      Shit, the dude writes and doodles like me. Good thing we use computer keyboards now. Otherwise, they'd haul me away for my writing.

    • It didn't look like there was anything new in his paper to me. When he wrote it, the theory of cryptography would have been much further advanced than that, the idea that cryptographic strength can at its best go up exponentially with key length is pretty obvious.

      It didn't look like he'd come up with a strong crypto system either; I suspect that the only reason anyone even looked at it was because he was a professor of mathematics and so they would have given him the benefit of the doubt, but the contents w

  • by Animats (122034) on Saturday February 18, 2012 @07:25PM (#39089165) Homepage

    What Nash seems to be describing is a feedback shift register. [wikipedia.org] This has potential as a cryptosystem, but isn't a very good one. As the NSA pointed out, it "affords only limited security".

    When Nash wrote this, Friedman [wikipedia.org] had already developed the theory that allowed general cryptanalysis of rotor-type machines. But that was still highly classified. Friedman, of course, was responsible for breaking the Japanese "Purple" cypher, plus many others. Before Friedman, cryptanalysis was about guessing. After Friedman, it was about number crunching.

    Friedman was the head cryptanalyst at NSA at the time. Within NSA, it would have been known that a linear feedback shift register was a weak key generator. So this idea was, properly, rejected. At least NSA looked at it. Friedman's hard line on that subject was "No new encryption system is worth looking at unless it comes from someone who has already broken a very hard one."

    The fact that a problem is NP-hard isn't enough to make it a good key generator. The Merkle-Hellman knapsack cryptosystem [wikipedia.org], the first public-key cryptosystem published, is based on an NP-hard problem. But, like many NP-hard problems, it's only NP-hard in the worst case. The average case is only P-hard. (Linear programming problems, and problems which can be converted to a linear programming problem, are like that.) So that public-key system was cracked.

    We still don't have cryptosystems which are provably NP-hard for all cases. Factoring and elliptic curves are as good as it gets, and there's still the possibility that a breakthrough could make factoring easy.

    • To be clear, "continuous" linear programming has polynomial-time algorithms. Integer linear programming does not, however.
  • by Anonymous Coward

    I've read the documents and i believe that i understand them but perhaps not. It appears that Nash has forgotten a + or - on one of the permutation rules. No that big of a deal as one should be able to deduce it's value from the other rules. But both values produce an infinite loop. Perhaps a mistake was made else where. It appears that the mechanics are there and are sound (insofar as its level of encryption).

    It would have been fun to work through it and perhaps implement it via simple JavaScript or someth

  • I've made a full transcript of the declassified PDF: http://www.gwern.net/docs/1955-nash [gwern.net]

Those who do not understand Unix are condemned to reinvent it, poorly. - Henry Spencer, University of Toronto Unix hack

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