[mythtv] [PATCH] Enable recording of encrypted channels withoutdecrypting them first.

James Courtier-Dutton james.dutton at gmail.com
Fri Jul 16 14:52:29 UTC 2010


On 16 July 2010 15:34, Allan Stirling
<dibblah.allan.stirling at googlemail.com> wrote:
> wf_myth_user at online.nl wrote:
>
>> But when the file is stored encrypted only people who have access to a cam
>> with smartcard can watch the file.
>> So for legal reasons option(2) would be the better solution.
>> When looking at it this way it would even make sense to move the cam and
>> smartcard to the frontend.
>>
>
> I'm not quite sure why all of this started but it's essentially impractical
> to do "offline" decrypting for a number of reasons:
>
> 1. There are no interfaces to hardware CAMs that are supported in Linux that
> allow arbitrary data to be passed to them. DVB cards take data from the
> demodulator and switch it either through the CAM or directly to the bridge
> chip. Very few video bridge chips have outputs and none that I have seen
> pass the output to the CAM, since it would have no purpose in a "normal"
> system. The Hauppauge standalone USB CAM is not supported under Linux.
Not True.

>
> 2. Keys change. This means that your recordings are only "valid" and
> decryptable at the time when they are recorded. Manufacturer PVRs get over
> this in a number of ways which are not possible for us since we do not have
> access to the internals of the CAM.
Not true.


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