W3C home > Mailing lists > Public > public-privacy@w3.org > July to September 2016

Re: common features with cross-origin correlation possibility

From: Lukasz Olejnik (W3C) <lukasz.w3c@gmail.com>
Date: Sun, 31 Jul 2016 23:25:20 +0100
Message-ID: <CAC1M5qoPdc6-R09r3307NJcyBA6fDOnLC4ospKWZHKGSySrqgA@mail.gmail.com>
To: Nick Doty <npdoty@ischool.berkeley.edu>
Cc: "public-privacy (W3C mailing list)" <public-privacy@w3.org>, Greg Norcie <norcie@cdt.org>
Hi Nick,

> * Simultaneously-triggered events
> APIs that allow for subscribing to events also introduce the possibility
> of correlating a user's activity across tabs, across origins or across
> browsers. (I've noted this before, apologies for repetition.) I believe the
> typical advice is to only trigger events for the front-most browsing
> context or to fuzz the timing; given that we have typical advice, we should
> have that written up somewhere.
> * Access to sensors or device data
> The Generic Sensor API is already getting into this, I believe. Since
> sensors typically give information about the world around the device, the
> data is inherently cross-origin and can enable unexpected correlations.
> Data on the device may be the same way -- in addition to the privacy issues
> with accessing my calendar appointments or my contact database, a site can
> also determine that I'm the same person if I share that information with
> more than one page.

I fully agree and support! It is one of my main points of analysis.
In addition, if a readout of a sensor is identical over time, this can also
lead to a cross-linkage.
I am working on a follow-up analysis.

> * Permanent, hardware identifiers:
> I think we should state that this is typically incompatible with the Web's
> privacy model. Access to an unchangeable identifier or hardware key means
> clearing cookies does not affect the capability of correlating user
> activity.
A good point. It is indeed an issue and I believe it may be the case of how
certain sensors will be exposed. It is already being discussed [1].

[1] https://github.com/w3c/sensors/issues/120

Received on Sunday, 31 July 2016 22:25:49 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 16:49:33 UTC