[Ffmpeg-devel] Re: HDTV, patents, DRM

[Måns Rullgård]

Mike Melanson <mike at multimedia.cx> writes:

> M?ns Rullg?rd wrote:
>> Mike Melanson <mike at multimedia.cx> writes:
>>
>>>Dave Dodge wrote:
>>>
>>>>True, though the content providers keep trying to add a "broadcast flag"
>>>>to the system.
>>>
>>> 	I think this is a big factor that holds up adoption of HD content-- 
>>>providers aren't willing to throw the switch unless they have some
>>>assurance that the consumers can't save the raw data wholesale (I
>>>know, it's a pipe dream on their part).
>> A good conditional access system makes it hard enough that nobody
>> will
>> do it, even if it can be done in principle.  Nobody has computers
>> powerful enough to crack a key of 100 or so bits every 10 seconds.
>
> 	I must not understand this particular cryptosystem very well--
> 	why would they need to crack the key? Surely, the key must be
> 	available some other way?

The keys are sent in the stream encrypted with one half of an
public/private key pair, the other half of which is embedded inside
the smartcard.  If you think cracking the private key is easier, go
ahead.  Or maybe it's possible to glean something using a bus analyzer
connected to some chips inside the STB.  Even so, it's difficult
enough that *very* few people will do it.

-- 
M?ns Rullg?rd
mru at inprovide.com