bonomi@host122.r-bonomi.com (Robert Bonomi) wrote:
> In article <telecom24.129.7@telecom-digest.org>,
> Dan Lanciani <ddl@danlan.com> wrote:
>> kd1s@nospamplease.cox.reallynospam.net (Tony P.) wrote:
>>> Sort of how the FCC has pretty much admitted that anyone with a
>>> modicum of technical knowledge will be able to defeat the broadcast
>>> flag.
>> I think you've mentioned this before, but what does it mean? The
>> system as originally conceived requires the digital representation of
>> flagged content to be protected by encryption on bus and media. I
>> have more than a modicum of technical knowledge and I don't see an
>> easy way around the proposed system in concept. Has the original
>> system been abandoned? Or are you aware of some implementation flaw?
> *Somewhere* in the TV set, the signal has to get decrypted, before it
> can be presented to the CRT, or other actual 'display'.
> Thus there *is* a "cleartext" signal running around inside the box.
> Thus, someone with a reasonable amount of skill can 'tap' the cleartext
> signal, and "voila!"
The original proposal required that the undegraded digital
representation of flagged content never appear on a bus (even the LCD
driver bus) in the clear, specifically to thwart such an attack.
(CRTs do not present the same kind of problem as LCDs because the
video can be converted to analog before it ever leaves the final
driver circuits. Of course, even if you could access the LCD driver
bus you would be getting a decompressed and possibly otherwise
manipulated version and not the original stream.)
Thus, there would be no clear text version of the signal "running
around inside the box" to tap. You would have to probe the dies of
the appropriate integrated circuits themselves. Although this is
certainly not impossible, it requires more than a modicum of technical
knowledge and also requires some specialized and rather expensive
equipment. Anyone willing to go to those lengths would be better
served by building an ATSC receiver from scratch.
This brings me back to my question: has the original approach been
abandoned? If not, I'm having a hard time understanding some of the
comments I've read that tend to minimize the impact of the broadcast
flag implementation. The only explanation I can think of is that
people have become so accustom to Macrovision, SCMS, and similar
stupidity that they don't understand that this time it's for real...
> And there's always the "idiot method" -- just point a camcorder at the TV.
The purpose of the broadcast flag (and all the associated DRM) is to
protect the undegraded digital representation of flagged content.
Your approach of creating a degraded analog rendition of the content
does not defeat that intent. In fact, as of now, we will supposedly
still be allowed to access the analog output of receivers, perhaps
even at HD resolution. If a copy to analog and back is what the FCC
(or anybody else) is considering a defeat of the broadcast flag then
I'm afraid they have really missed the point.
Dan Lanciani
ddl@danlan.*com
Dan Lanciani (ddl@danlan.com)