Re: [dispatch] Updated PERC Charter proposal

[Paul Kyzivat <[e-mail]>]

On 6/3/15 8:58 AM, Magnus Westerlund wrote:
> Hutton, Andrew skrev den 2015-06-03 10:42:
>> I agree there is some value in exploring the recording use case it is
>> one of the first questions everybody asks when discussing PERC.
>
>  From my perspective there are two ways of doing recording of media
> content in PERC.
>
> 1. Invite the recorder as a full fledged authenticated session
> participant that use the normal way of getting the keys to the media as
> any other endpoint.
>
> 2. The recorder only stores the encrypted media content, thus being a
> semi-trusted entity to that are allowed to get a copy or be integrated
> into the central forwarders. At the time one wants to access the
> recorded content one will have to request the relevant keys from the
> key-management function, that will also have to have stored the relevant
> group keys for the session to enable decryption.
>
> I would claim that the second one is the securer, and enables better
> tracking of who access recordings of a secured conference.

These sound reasonable to me. IIUC, (2) could be complicated because 
each time a new participant joins or leaves there must be new keys.

	Thanks,
	Paul

>> Hope we are allowed to consider this.
>
> The charter talks about informing and coordinating with SIPREC. This to
> have an exchange about the possibilities. However, it is not a work item
> of the PERC WG to specify a solution for recording. I would expect any
> technical work on solving PERC recording would need to be chartered in
> the most relevant WG. I think the ones interested in recording should be
> active in the WG work to ensure that the developed solution do support
> recording. If there are contention between the goals, then we will need
> to have a serious discussion. But, remember that we have clear goals of
> ensuring end to end security, thus compromises to the security model to
> fit recording will be unlikely to be accepted.
>
> Cheers
>
> Magnus Westerlund
>
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