Re: [ietf-privacy] [Geopriv] Nits about draft-ietf-geopriv-held-measurements-06.txt

On Apr 11, 2013, at 6:55 PM, Martin Thomson <martin.thomson@gmail.com> wrote:
>> Here are some nits (feel free to ignore).  Section 6 mentions that:
>> 
>>  "In order to protect the privacy of the subject of location-related
>>   measurement data, this implies that measurement data is protected
>>   with the same degree of protection as location information."
>> 
>> Section 6.2 mentions that:
>> 
>>  "By adding measurement data to a request for location information, the
>>   Device implicitly grants permission for the LIS to generate the
>>   requested location information using the measurement data.
>>   Permission to use this data for any other purpose is not implied."
>> 
>> and
>> 
>>  "A LIS MUST discard location-related measurement data after servicing
>>   a request, unless the Device grants permission to use that information
>>   for other purposes."
>> 
>> How can a device implicitly grant permission?  It is up to the user to grant
>> permission.
> 
> Ah yes, I'm not sure whether this was made explicit in this draft
> (probably not), but we take the view that the Device is a proxy for a
> user (Target in geopriv-parlance).  In terms of protocols and location
> determination that's the only reasonable assumption to make.  That's a
> really important point though, not something we should be taking on
> faith.  I'll make sure to add a note.
> 

You could reference the role definitions in RFC 6280 (section 2) for this.

Alissa

>> The specification also sends information, e.g. for wifi, which might not
>> readily available to the cellular operator.  The privacy model followed can
>> be described as the unknowingly informant model.
> 
> I don't know where you are going with the "unknowingly informant
> model", but it's true that in some cases, measurements that are
> provided to a LIS might not be useful. If your LIS is operated by a
> cellular operator, then maybe (though it's only a maybe) the cellular
> operator wont be able to use the information to improve a location
> estimate.  Similarly, they might not know how to deal with GLONASS
> pseudoranges.
> 
> Implementations have choices on the spectrum between: provide nothing
> and see if the LIS asks for more information; and provide everything
> and don't worry about the extra stuff.  The latter choice actually has
> some implications with respect to performance and time, so most likely
> it will go somewhere in between the two.
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