[kwlug-disc] Future of [Rogers] PVR (wrt HDMI)? Black boxes? MythBuntu?

Andrew Kohlsmith (Mailing List Account) aklists at mixdown.ca
Tue Sep 15 08:10:28 EDT 2009


On September 9, 2009 09:54:20 am john at netdirect.ca wrote:
> In fact if you look closely at HDMI and Blu-ray you find that the
> technology allows for disablement of devices.
>
> HDMI and Blu-ray devices each have a manufacturer key that is used to
> negotiate an encryption key with other devices. Blu-ray media has the
> publisher's media key that must be authenticated before playing.
>
> Blu-ray media also has an update block that contains updates to the key
> sets. One possible update is key revocation. If a blu-ray disk contains a
> key revocation update for your big expensive HDMI-connected TV, and you
> put that in your player, it may refuse to play on your TV. It may even
> disable your player, although that's not clear.

There is a research paper which seems to indicate that HDMI's encryption is 
wholly and thoroughly broken, and it's possible to regenerate the HDCP 
**signing** key from 40 HDMI key pairs (available from any HDCP-enabled 
devices):

http://www.cypherpunks.ca/~iang/pubs/hdcp-drm01.pdf

Now the math is well and truly beyond my capabilities, but the attack is 
there, and is practical.

Another semi-practical (for the hacker) attack is to "simply" take the 
decrypted pixel bus that comes out of an HDMI receiver chip and feed it into 
an FPGA "frame grabber" card.  There are many cheap HDMI capable monitors and 
TVs which would allow for this kind of attack vector.

More practical than that are the HDMI HDCP "strippers" available off of eBay.  
I haven't purchased one yet.

> As for formats I don't know if Myth will play an ISO image. It will play a
> DVD I think.

Myth plays ISOs and directories of DVD content just fine (think directories 
full of VOB files, menu data, etc.)

-A.




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