Re: Follow up issues from WebRTC / PING TPAC meeting

cc public-privacy <public-privacy@w3.org>

On 10/8/19 8:20 AM, Harald Alvestrand wrote:
> Den 05.10.2019 06:24, skrev Jan-Ivar Bruaroey:
>>>   https://w3c.github.io/mediacapture-main/#dom-mediadeviceinfo-deviceid mentions
>>> unguessability, but I didn't see a reason why that would be needed.
>> I suspect we just meant nondeterministic across origins.
>>
> My memory says that we wanted to avoid pages learning about devices by
> probing into a small ID space.


You mean probing using getUserMedia()? That makes sense as having been 
the concern then. Though put in context, pages could still do that for 
the super-set of all devices the user has even without valid ids, and 
most users have one camera (or two on phones, which are already 
distinguishable using the facingMode constraint).

But now, if we're moving toward not exposing deviceIds 
pre-initial-gUM-grant, (as well as neutering OverconstrainedError's 
constraint property in this case) then this shouldn't be a concern 
anymore, I don't think, and we could use smaller ids without this risk.


> 1, 2, 3 is a small ID space; UUID space is large enough that one
> normally ignores the chance of collision; for unguessability, probably
> an ID space on the order of a million distinct IDs is quite large enough.

.: Jan-Ivar :.

Received on Tuesday, 8 October 2019 20:11:59 UTC