The Fortezza random number generator is not trustworthy

Eric Blossom eb at comsec.com
Tue Sep 26 15:25:03 PDT 1995


> On a technical note, I would have thought that Fortezza and/or CAPSTONE used
> some sort of hardware RNG, i.e. noisy Zener diodes or whatever.  I've seen it
> mentioned on this list that some other NSA secure phones, such as STU-III,
> do that.

I was under the impression that a seed for the RNG is loaded into the
Fortezza at initialization time.  This would make me think that they
are using a cryptographically strong PRNG.  This would give data that
appears random, but is completely determined by the initial state.

I suspect that the "seed keys" provided by the two agencies used to
program the Clipper chips has the same properties.  This makes the
question about how does the NSA get access to the key escrow database
moot.  They don't need access.  They know a priori all the unit keys.






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