[14611] in Cypherpunks
Re: News Flash: Clipper Bug?
daemon@ATHENA.MIT.EDU (Allen J. Baum)
Thu Jun 2 18:05:14 1994
Date: Thu, 2 Jun 94 14:55:54 PDT
To: cypherpunks@toad.com
From: baum@newton.apple.com (Allen J. Baum)
koontzd@lrcs.loral.com (David Koontz )>
>I've been saying it can be done for more than a year. I wrote a C model
>of some operating code for the chip. The clipper chip has save and restore
>commands that are used to dump and restore the LR register (crypto state).
>You keep your own LEAF and feed it back to the chip. You take the initial
>value of the LR register after IV generation and reload, it contains the
>IV. You exchange IVs with the distant end, who has also feed his own
>LEAF back to his chip. You have achieved crypto sync.
Where did you get the information about the internals?
I've seen no references at all.
>2) There might be anti-tamper features (re: FIPS Pub 140-1), causing loss
> of crypto variables (say for key exchange). It might be possible the
> TSD won't operate it all if security features are tripped. (unlikely,
> when you consider mechanical switches might bounce when one of these
> is thrown is a briefcase).
Hmm- a lot of the pay-TV cable boxes have security like that, and they work
just fine.
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