From: "Perry E. Metzger" <perry@piermont.com>
Date: Sun, 31 Mar 1996 20:19:04 +0800
To: Mike Ingle <inglem@adnetsol.com>
Subject: Re: [CRYPTO] Cable-TV-Piracy-Punks
In-Reply-To: <199603310256.SAA00348@cryptical.adnetsol.com>
Message-ID: <199603310350.WAA17724@jekyll.piermont.com>
MIME-Version: 1.0
Content-Type: text/plain



Mike Ingle writes:
> The big latent assumption here being that you have only one-way
> communication with the subscribers. DSS has a modem.

I am assuming that you mean that DSS has a phone line attached and can
call home. If this is merely a two way satelite communication it isn't
useful for this purpose.

> It could get a new key from a distribution center frequently -
> i.e. every day. Then the pirates would somehow have to update their
> keys daily, in real time.

You mean, perhaps the pirates would have to distribute keys over the
internet or some such? How horrid.

The problem is, as I said, insoluble. You cannot defend against
hostile users of the system because each user gets the same encrypted
data stream. 

> Once we have live packet communication (cable modems or ISDN D-channel,
> for example) the keys can be changed minute by minute, if necessary.

And could be updated to millions of people getting the signal
illegally via the same mechanism.

> The pirates will have to run their own network parallel to the
> legitimate one to distribute the keys. Therefore piracy requires an
> ongoing organization, and is subject to being tracked down.

No one said it wasn't subject to being tracked down, although the use
of offshore packet laundries might make it hard. Cellphone fraud is
subject to being tracked down, too, and yet it happens to the tune of
billions a year.

Perry