[tvcontrol-api] Decryption of encrypted channels

tidoust has just created a new issue for 
https://github.com/w3c/tvcontrol-api:

== Decryption of encrypted channels ==
When an application tunes in to an encrypted channel, the decryption 
happens automatically provided the right CI Card is present on the 
system. My understanding is that this decryption is not tied to any 
particular origin: if the Card is there, any app can decrypt the 
content.

On the Web, EME comes to mind as an API to control playback of 
encrypted content. One advantage of using EME is that the application 
explicitly requests media keys for decryption and these keys are per 
origin. This provides a mechanism to restrict the decryption of 
encrypted channels to Web domains that are authorized to do so (as 
required by the [presentation restrictions use 
case](https://www.w3.org/wiki/TV_Control/Use_Cases#Presentation_restrictions)).

>From a technical perspective, the use of EME seems already doable with
 the current API, at least in theory: if you get an encrypted media 
stream, you should be able to plug it into an `HTMLMediaElement` and 
then use EME to associate media keys with it.

However, the current API seems to assume that encrypted channels can 
always be associated with a CAS system ID. If EME seems like a useful 
possibility in some cases, applications probably need a way to tell 
whether a channel is going to need EME (and to filter out such 
channels if they know they cannot decrypt them).

I haven't thought much about the topic. Just raising this as an issue 
so that he group keeps an eye on it.

Please view or discuss this issue at 
https://github.com/w3c/tvcontrol-api/issues/17 using your GitHub 
account

Received on Friday, 21 October 2016 08:24:32 UTC