From: phelix@vallnet.com
Date: Thu, 9 Oct 1997 19:45:35 +0800
To: cypherpunks@Algebra.COM
Subject: Re: Internet Via Electric Lines? (fwd)
Message-ID: <34458bd4.96061987@128.2.84.191>
MIME-Version: 1.0
Content-Type: text/plain



On 9 Oct 1997 02:25:13 -0500, "William H. Geiger III" <whgiii@invweb.net>
wrote:

>
>-----BEGIN PGP SIGNED MESSAGE-----
>
>In <199710081234.HAA11747@einstein.ssz.com>, on 10/08/97 
>   at 07, Jim Choate <ravage@ssz.com> said:
>
>>Forwarded message:
>
>>> From: "William H. Geiger III" <whgiii@invweb.net>
>>> Date: Wed, 08 Oct 97 01:28:42 -0500
>>> Subject: Re: Internet Via Electric Lines?
>
>>> This is nothing new.
>
>>At least late 70's.
>
>>> I think it was GE that several years ago created phone extensions that you
>>> plugged into your power outlets, no need to run wire to put in an extra
>>> outlet. I believe that X-10 uses this same principle for computer control
>>> of household appliances.
>>> 
>>> Not to mention data leakage through power lines is an issue long reconized
>>> by the TEMPEST crowd.
>>> 
>>> The trick here seems to be in routing the data. How do you get data on the
>>> power grid routed to the location that you want it to go??
>
>>The trick with X-10 is to stay away from transformers as the signal won't
>>go through them effectively. This ends any dreams of sending data to your
>>neighbor, the signal won't go through your power meter.
>
>This seems to be a Goodthing(TM) for residential X-10 as it would seem to
>take care of a lot of security issues by effectively isolating each home
>from others who may be running the same system.
>
>Has anyone researched the security issues around X-10? Is the Transformer
>isolation good enough protection from a dedicated attack (as opposed to
>accidental signal leakage)? Are their alternative routes for transmitting
>the FM signal (Airwaves) that the X-10 devices would pick up?? Do any of
>the current X-10 devices use signal authentication/verification?
>

X-10?  security?  hehehe... that's good for a laugh.

There is no security whatsover in X-10.  If your neighbor knows the
addresses of your X-10 units and his power comes off the same transformer
as yours, he can easily turn your lights on and off.  The only thing
protecting you (besides obscurity) is the transformer that isolates your
power line from others.

X-10 doesn't use any type of FM signal.  It simply transmits bits in the
zeros of the ac power 'signal'.  It only get 120bps and most signals are
repeated 3 times (even with that, the signal sometimes gets lost in the
line noise), so really you only get 40bps.   A command consists simply of
[address],[command].  The address is 8 bits long, I dont' remember how long
the command is.  In X-10 speak, and address is [A-P] [1-16].  The commands
are on,off,bright,dim,all-lights-on, and a few others.

There's no security, no encryption, not even collision detection when using
more than one transmitter.

Now, there a new system called cebus, but it's over 10X more expensive.  I
don't know too much about it.

-- Phelix