John Nash's Declassified 1955 Letter To the NSA 93
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.'"
Some Links to the NSA site (Score:5, Interesting)
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]
Communication as a form of intelligence (Score:5, Interesting)
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.
Re:(Read all of it) Nash gets form letter rejectio (Score:5, Interesting)
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.