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Re: ACTION-286: Propose DAA text regarding de-identification (for unlinkability discussion)

From: Ed Felten <ed@felten.com>
Date: Thu, 15 Nov 2012 13:47:03 -0500
Message-ID: <CANZBoGidoWDqsmd1ZuC5YVMDfbCKNfkDzagODDavmMB9bg4RaQ@mail.gmail.com>
To: Chris Mejia <chris.mejia@iab.net>
Cc: Rachel Thomas <RThomas@the-dma.org>, "public-tracking@w3.org" <public-tracking@w3.org>, Louis Mastria <lou@aboutads.info>, "David Wainberg (david@networkadvertising.org)" <david@networkadvertising.org>, Mike Zaneis <mike@iab.net>, "mgroman@networkadvertising.org" <mgroman@networkadvertising.org>, Brendan Riordan-Butterworth <Brendan@iab.net>
There's still a contradiction here.   In order to maintain a profile over
time, you have to recognize over time that all of the accesses in the
profile are coming from the same user or device.   That would seem to
require that you can tell that user or device apart from all other users or
devices over time.

Rachel's definition doesn't talk about whether you can link to PII.   It
talks about whether you can link to a specific person or device--which you
can do without knowing any PII.

On Thu, Nov 15, 2012 at 12:15 PM, Chris Mejia <chris.mejia@iab.net> wrote:

>   Hi Ed,
>  I believe the demarkation here is with respect to PII and getting back
> to the specific person/device.  Per the DAA language Rachel has provided
> (cut-and-pasted from the DAA self-regulatory document) to this working
> group, a unique profile may be maintained so long as it cannot reasonably
> be re-associated or connected to an INDIVIDUAL and/or a PARTICULAR computer
> or device.  This is done through one-way hashing.  In other words, this
> unique profile can still exist, but it cannot be connected to a specific
> person/device.
>  Chris Mejia | Digital Supply Chain Solutions | Ad Technology Group |
> Interactive Advertising Bureau - IAB
>   From: Ed Felten <ed@felten.com>
> Date: Thursday, November 15, 2012 8:45 AM
> To: Rachel Thomas - DMA <RThomas@the-dma.org>
> Cc: W3C DNT Working Group Mailing List <public-tracking@w3.org>, Lou
> Mastria - DAA <lou@aboutads.info>, Chris Mejia - IAB <chris.mejia@iab.net>,
> David Wainberg - NAI <david@networkadvertising.org>, Mike Zaneis - IAB <
> mike@iab.net>, Marc Groman-NAI <mgroman@networkadvertising.org>, Brendan
> Riordan-Butterworth - IAB <brendan@iab.net>
> Subject: Re: ACTION-286: Propose DAA text regarding de-identification
> (for unlinkability discussion)
>  There is a contradiction between this definition and the interpretation
> that you put on it.  The definition requires that the data "cannot
> reasonably be reassociated or connected to an individual..."   But the
> interpretation that is offered would allow situations where the data is
> used "to recognize ... specific visitors to Web sites".   That's a
> contradiction--if you use a data item to recognize a specific visitor, then
> you are reassociating and connecting that data to that specific visitor.
> On Thu, Nov 15, 2012 at 10:07 AM, Rachel Thomas <RThomas@the-dma.org>wrote:
>>  As I promised Aleecia during yesterday’s TPWG call, I am submitting the
>> Digital Advertising Alliance (DAA) definition of “de-identification” to
>> fulfill Action 286<https://www.w3.org/2011/tracking-protection/track/actions/286>in advance of the deadline this Friday.
>> ****
>> ** **
>> The DAA definition is as follows:****
>> ** **
>> *“De-Identification Process: *Data has been De-Identified when an entity
>> has taken reasonable steps to ensure that the data cannot reasonably be
>> re-associated or connected to an individual or connected to or be
>> associated with a particular computer or device. An entity should take
>> reasonable steps to protect the non-identifiable nature of data if it is
>> distributed to non-Affiliates and obtain satisfactory written assurance
>> that such entities will not attempt to reconstruct the data in a way such
>> that an individual may be re-identified and will use or disclose the
>> de-identified data only for uses as specified by the entity. An entity
>> should also take reasonable steps to ensure that any non-Affiliate that
>> receives de-identified data will itself ensure that any further
>> non-Affiliate entities to which such data is disclosed agree to
>> restrictions and conditions set forth in this [definition].”****
>> ** **
>> It is worth noting that this approach to de-identifying data is modeled
>> on the Federal Trade Commission (FTC) approach to masking online
>> identifiers to protect children under the Children’s Online Privacy
>> Protection Act  (COPPA). For example, the FTC states in question #45 of its COPPA
>> FAQ <http://www.ftc.gov/privacy/coppafaqs.shtm> that Web sites that
>> “hash” or otherwise alter children’s email addresses when collecting them
>> to be stored and used to create a password reminder system are not deemed
>> to be collecting and using personal information and, therefore, do not
>> trigger COPPA’s parental consent requirement. (Hashing being a one-way,
>> irreversible process that protects the original data but permits ongoing
>> indexing of the hashed values on an anonymous or de-identified basis). The
>> rule that emerges from this is that it suffices for purposes of protecting
>> privacy if identifiers are altered after they are collected such that they
>> cannot be reconstructed into their original form in the ordinary course of
>> business but the altered form remains available to be used by Web sites to
>> recognize and distinguish among specific visitors to Web sites.****
>> ** **
>> Thanks, and best,****
>> Rachel**
>> * *
>> *Rachel Nyswander Thomas*****
>> Vice President, Government Affairs****
>> Direct Marketing Association****
>> (202) 861-2443 office****
>> (202) 560-2335 cell****
>> rthomas@the-dma.org****
Received on Thursday, 15 November 2012 18:47:47 UTC

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