Re: Any truth to rumor that NSA had Public Key Crypto first?

From: Bill Unruh (unruh_at_string.physics.ubc.ca)
Date: 09/29/04 

Date: 29 Sep 2004 16:34:56 GMT

Bernie Cosell <bernie@fantasyfarm.com> writes:

]unruh@string.physics.ubc.ca (Bill Unruh) wrote:

]} No, that is not what he says. He says that NIST asked for a public
]} encryption standard. NSA probably did not want to give them a private one
]} precisely because they did not want to reveal their state. They weakened
]} DES by making the key short, and strengthened it with the Sbox design.
]} Basically this meant only they had a chance of breaking it. (good Sbox so
]} only exhaustive search works, short key so that they but not others could
]} actually carry out exhaustive search.)

]Perhaps I'm not understanding, quite, but I thought that shortening the key
]*did*not* weaken DES. Giving DES a much longer key than they actually did
]would have been *false*security*, since there are brute-force techniques
][that I assume NSA knew even if we civilians didn't at the time] for
]cracking it that ran only at what, 2^52 or the like..

Brute force depends on the length of the key.