[mythtv-users] Firewire no longer required on HD STBs

[Gabe Rubin]

On Wed, Jun 30, 2010 at 12:46 PM, Simon Hobson <linux at thehobsons.co.uk> wrote:
> Eric Sharkey wrote:
>
> Hmm, someone point out where my logic fails here ...
>
> * It's OK for the stuff on FireWire (or the new ethernet option) to be
> encrypted because a TV set manufacturer can decrypt it.
>
> * The cable network uses common standards - at least I imagine the cable
> companies are too tight to pay to have their own proprietary kit made (I
> assume a lot of it is common and just has their name on the front).
>
> * Some TVs have cable tuners/decoders.
>
> So in theory it should be possible for a standard TV to tune, decrypt, and
> decode off-the-cable signals. Though I guess it would need a slot for a
> subscription card.
>
> At which point the penny drops - the cable companies probably won't release
> a CI module as they'd rather make their subscribers pay over and over again
> for a grotty decoder box.
> --

My understanding is that the content that comes out of firewire is not
encrypted, so the tv has no need to decrypt it.  It just recognizes
the 5C flag that says "allow record"; "allow watch once"; "don't
allow"; etc.  The TV can display anything with a flag of a certain
level or higher (i.e., "allow watch once") and a recording device
(such as a mythbox) can only display/capture anything with a flag of
"allow record" or higher.  It is basically, does this device have
permission to access this content, not can this device decrypt the
stream because there is no encrypted stream to decrypt.