From: baum@newton.apple.com (Allen J. Baum)
Date: Thu, 2 Jun 94 14:56:50 PDT
To: cypherpunks@toad.com
Subject: Re: News Flash: Clipper Bug?
Message-ID: <9406022155.AA20652@newton.apple.com>
MIME-Version: 1.0
Content-Type: text/plain


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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