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From: jeff@gatech.EDU (Jeff Lee)
Newsgroups: sci.crypt
Subject: VC-II key distribution (was - This is *stupid*)
Message-ID: <7277@gatech.EDU>
Date: Thu, 4-Dec-86 15:31:57 EST
Article-I.D.: gatech.7277
Posted: Thu Dec  4 15:31:57 1986
Date-Received: Fri, 5-Dec-86 04:57:35 EST
References: <12246@watnot.UUCP> <4725@yale-celray.yale.UUCP>
Reply-To: jeff@gatech.UUCP (Jeff Lee)
Distribution: net
Organization: School of Information and Computer Science, Georgia Tech, Atlanta
Lines: 26

Does anyone know where the key information is placed in the VC-II encryption
scheme?  It seems to me that if the information were stored in the horizontal
or vertical retrace that you could build a box that you could switch out, have
your favorite channel turned on, and then switch it back in and have it strip
out anything extra once it detects a retrace. Something similar might could
be done if they were using a portion of the picture that would normally be
taken up by the overscan on most TV's. Or are they doing something more
sophisticated by maybe putting another signal similar, but different, to the
audio portion?

It just seems that if they are not using some sort of public key encryption
to bootstrap into the DES then there is big hole out there. Your receiver is
receiving a key somehow. Even then, if you know where it is located and can
filter it out of the signal once it is turned on, that is as good as any
other black box. You just buy all the stations you want 1 time.

If I were a hardware jock, this would just seem to be a real interesting
"challenge". Something akin to the Scientific American article on RSA that
printed the encrypted message that used 60+ digit encryption keys and
offered some kind of award to anyone who could break it.

	Cheers,
-- 
Jeff Lee
CSNet:	Jeff @ GATech		ARPA:	Jeff%GATech.CSNet @ CSNet-Relay.ARPA
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