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[Action-106][Issue-32] Sharing of data between entities via cookie syncing / identity brokering

From: TOUBIANA, VINCENT (VINCENT) <Vincent.Toubiana@alcatel-lucent.com>
Date: Wed, 8 Feb 2012 13:11:24 +0100
To: "public-tracking@w3.org" <public-tracking@w3.org>
CC: "heatherwest@google.com" <heatherwest@google.com>
Message-ID: <4D30AC7C2C82C64580A0E798A171B44448892B84B9@FRMRSSXCHMBSD1.dc-m.alcatel-lucent.com>
The title might be misleading; it is not in fact about cookie-syncing between different browsers but different domains. Please find bellow the text that Heather and I drafted.
Vincent


Background:
In a cookie syncing procedure a Demand-Side Platform (DSP) aim to match a cookieXYZ (corresponding to its domain) to the cookieABC set by the Supply Side Platform (SSP) for the same User-Agent U. Cookie syncing requires that the SSP adds a 1x1 pixel from the DSP domain. The SSP has to pass the string “cookieABC” corresponding to ids domain to the DSP through the URL of this 1x1 pixel. The DSP parses the “cookieABC” in the URL and associates it to the cookieXYZ for its domain. Once the cookies have been matches, the DSP will be able to re-target U on the SSP affiliated sites.
The solution consists in not allowing cookie syncing when the SSP receives DNT:ON. If it did not, the SSP may start the cookie syncing process but the DSP must not synchronize the cookies if it received DNT:ON.
*The reason is that if the SSP publishes ads on a limited number of websites, the DSP would know that the client visited at least one of these websites.*

Pseudo-normative
The operator of domain acting as a third party (SSP) on a website and receiving [DNT-ON]  MUST not load content from a second unaffiliated third party domain (DSP) to transfer a user ID to this third party.
A third party receiving [DNT-ON] and a user ID through the URL loaded from an unaffiliated entity acting as a third party
MUST NOT associate the ID of the cookie sent in the request to the user ID transmitted in the URL and
MUST NOT collect or use other information related to that communication and not covered by the 3rd party exemption.
Received on Wednesday, 8 February 2012 12:17:06 UTC

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