[vdr] Re: Child protection / access control module

[Oliver Endriss <o.endriss@gmx.de>]

Klaus Schmidinger wrote:
> I guess there are a few basic things that need to be considered
> before implementing this. For instance, should there be separate PINs
> for each operation, like "modifying the setup", "setting/deleting
> timers", "deleting recordings", "watching age restricted
> channels/recordings" etc., or should there be _one_ PIN for each
> user, which can be assigned various "rights"? I believe the latter
> would be better, since each user would only have to memorize _one_
> PIN and the system administrator could set him/her up with whatever
> VDR uses access control for.

Full Ack. And please, if the administrator PIN has been set to 0000,
the whole authorization stuff should be disabled. :-)

> - access things restricted to "age >= N years" (N = 6, 12, 16, 18;
> this can be favourite channel lists, individual broadcasts (provided
> their EPG data includes age information), or recordings (provided the
> EPG data at the time of the recording contained age info)

The transmitted service information *should* contain a parental 
rating descriptor (ETSI 300 468, p. 53). 
I don't know whether this descriptor is transmitted by all stations or 
the transmitted data is reliable at all. I have some doubts...

Anyway, if present, this descriptor should be used to further restrict 
access:
  vdr user <= 6 years
  setting for channel: >= 0 years
  parental rating descriptor: min age 12
  ==> programme blocked

It must not be used to extend access in case bogus data is transmitted:
  vdr user <= 6 years
  vdr setting for channel: >= 12 years 
  parental rating descriptor: min age 0
  ==> channel blocked

> What concerns me the most is: when should the PIN be checked?
> Clearly it should be checked, for instance, when a recording is
> selected for playback that has some age restriction. That would be a
> one time check at the start, and that's it.

Recordings, for which I don't have access rights, should be invisible.
I don't like the imagination that I have to enter the PIN again
for each 3 minute music clip. I'd prefer to log-in once and have 
the assigned rights as long as the session lasts. There should be a 
programmable inactivity time-out (0 means no time-out). 

> So, should there be a
> "timeout" for the "validity" of an authorization? Like, if you have
> entered your PIN you may switch channels until you stay with a
> specific channel for a certain amount of time. After that you'll need
> to re-authenicate yourself. 

Sounds good. Setting the timeout to 0 should disable the feature.

> What if you switch to an age restricted
> programme and then turn off the tv (and leave VDR running)? The next
> person who turns on the tv would be able to see the restricted
> programme without authorization. So, should an authorization only be
> valid as long as the current programme runs?

This might be really annoying. If implemented, this should be a 
configurable option. 

Whenever a parental rating descriptor is received, which forbids the 
programme for the current user, the display must be turned off.

> I hope this helps to put this thread back on a more technical basis
> ;-)

Good idea :-)

Oliver



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