-----Original Message-----
From: owner-ip-dvb@erg.abdn.ac.uk
[mailto:owner-ip-dvb@erg.abdn.ac.uk]On
Behalf Of ext Allison, Art
Sent: Thursday, March 25, 2004 6:01 PM
To: 'ip-dvb@erg.abdn.ac.uk'
Subject: RE: Security Considerations section for
Sniped part and replied..
Art
::{)>
Art Allison
Director Advanced Engineering
NAB
1771 N St NW
Washington DC 20036
202 429 5418
-----Original Message-----
From: Gorry Fairhurst [mailto:gorry@erg.abdn.ac.uk]
Sent: Thursday, March 25, 2004 4:48 AM
To: ip-dvb@erg.abdn.ac.uk
Subject: Re: Security Considerations section for
I'm quite happy to try to summarise the security thread - or
get someone
else to - I'll leave it a few days to see if there are any
comments/issues
from other people to add.
I have a small number of questions for clarifications...
...
<snip>
Art Allison wrote:
Second, it seems out of scope to put elements in the RF
emissions that
belong in the contribution process. It seems that you are
concerned about
attacks on the data flow up to the RF emission. This is a valid and
important concern; but seemingly not relevant to a light
weight emission
Protocol.
Gorry Fairhurst asked:
Would such contribution feeds normally use MPEG-2 transmission?
AA responds> They generally do although not necessarily in
strict compliance
with the MPEG-2 transport standard. Often 45Mpbs per RF
channel with higher
profile and level is used so that the content can survive decoding and
recoding. Some are distributing at payload rates. ATM is used
by some (with
MPEG-2 packet mapping onto the ATM cells).
Gorry Fairhurst asked:
To what extent do you envisage these TV contribution feeds to carry IP
packet data?
Art responds>
Perhaps lots, perhaps little, but MUCH more importantly the
contribution
contains very valuable content to the broadcaster, that
normally they are
contractually bound to protect anyway. It contains the A/V
programming and
lots of folks would like to rip that off. So, I would specify that
everything in the contribution link be protected with
encryption and that
further I would not want it to be standard as that increases
the size of the
target for attackers. The two ends of a contribution link
have always worked
best when they come from the same vendor anyway. There are several
approaches to protect an entire link, but protection of this
feed is not the
job of the particular type of content embedded therein. If
you assert that
you should put protection on ULE content type, to be
logically consistent
you would have to assert that each content type have a
protection scheme at
this layer.
If the threat is significant enough, (and for the
contribution link I agree
it is) protect it ALL.
But that protection-for-it-all is out of scope here and is
already being
used today (I am not aware of any in-the-clear contribution
links in the
US.)