From: sommerfeld@localhost.medford.ma.us (Bill Sommerfeld)
Date: Fri, 3 Jun 94 07:12:47 PDT
To: cypherpunks@toad.com
Subject: more info from talk at MIT yesterday.
Message-ID: <199406031357.JAA00376@localhost>
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The folks from the NSA said the following about key generation:
	
	- each escrow agency provides a "seed key", seed1 and seed2
	- the box which programs the chip generates two random keys,
	random1 and random2
	- for each chip programmed during that batch (which is "12 to
14 hours of production"), the box computes a
	classified deterministic function
		(U1, U2) = F(serial, random1, random2, seed1, seed2)
	to generate the unit keys


They did *not* explicitly say that the random seeds were destroyed at
the end of the production run.

Also, someone asked
	"How do we know that the unit key isn't a hash function of
	the chip serial number?"

The answer was:

	"You don't".

They also confirmed Tom Knight's suspicions about what they're going
to do when someone reverse engineers the chip and publishes the
Skipjack algorithm & the family key: they've got a patent application
filed, under a secrecy order; if the algorithm is published, they'll
lift the secrecy order and have the patent issued, and use that to go
after anyone making a compatible version.

They also had a comment that they considered Blaze's findings to be
mostly irrelevant, as the only people who would use it would be
persons who *didn't* trust the escrow system, but *did* trust the
algorithm...

					- Bill