- From: Rob van Eijk <rob@blaeu.com>
- Date: Wed, 10 Jul 2013 17:33:29 +0200
- To: Justin Brookman <jbrookman@cdt.org>, "Mike O'Neill" <michael.oneill@baycloud.com>
- CC: "'Shane Wiley'" <wileys@yahoo-inc.com>, public-tracking@w3.org
- Message-ID: <763b074f-d9b6-4639-af93-13a1e4b2fa38@email.android.com>
Justin, currently aggregated scoring happens parallel from R-Y-G, and is not part of the proposal. In Santa Clara Shane made it clear that all users, regardless of DNT will be subject to aggregated scoring. Only an opt-out cookie MAY prevent this collection, use and sharing. Rob Justin Brookman <jbrookman@cdt.org> wrote: >To be clear, I do not believe that the term "aggregate scoring" appears >either in the original DAA proposal or the amendments that Jack sent >around yesterday. As I currently think I understand the proposal, when >DNT:1 is turned on, a third party may not use/retain the specific >url/domain for OBA (or other non-permitted purposes), but they may >use/retain any derived information about the url. > >So an ad network may not retain/use the fact that I visited >zappos.com/32145 for OBA (or other non-permitted purposes) but they may >retain/use/sell/do anything with a characterization of my unique ID as >"interested in shopping," "interested in shoes," or "interested in the >Nike Pro Attack in blue and green." The unique ID could be a cookie, >an email address, a name, or anything else. > >Justin Brookman >Director, Consumer Privacy >Center for Democracy & Technology >tel 202.407.8812 >justin@cdt.org >http://www.cdt.org >@JustinBrookman >@CenDemTech > >On Jul 10, 2013, at 11:15 AM, "Mike O'Neill" ><michael.oneill@baycloud.com> wrote: > >> [Keep ID, Remove URL = Aggregate Scoring] is a null >> Because the individual is still profiled and their web activity can >continue to be appended to the profile >> >> [Remove ID, Keep URL] is a null >> Because a) PII might be in URLs. >> b) In reality ID has been replaced with an >equivalent, though different, ID’ so web activity can continue to be >appended. >> >> From: Shane Wiley [mailto:wileys@yahoo-inc.com] >> Sent: 10 July 2013 15:42 >> To: Mike O'Neill >> Cc: public-tracking@w3.org >> Subject: RE: issue-199 >> >> Mike, >> >> I support verifiability but am challenged with technical mechanisms >to allow this without breaking corporate confidentiality concerns. >This is why I call it out as an area for future development to help >build solutions to this unique problem. >> >> I’ve tried breaking the proposal down to the simplest form I can >think of. Let me know if this makes it more clear: >> >> ----- >> If Tracking = ID + URLs, then Not Tracking = ID <> URL >> >> Keep ID, Remove URL = Aggregate Scoring >> Remove ID, Keep URL = De-Identification >> >> Remove ID, Remove URL = De-Identification + De-Linking (now out of >scope of DNT) >> ----- >> >> - Shane >> >> From: Mike O'Neill [mailto:michael.oneill@baycloud.com] >> Sent: Wednesday, July 10, 2013 3:10 PM >> To: Shane Wiley >> Cc: public-tracking@w3.org >> Subject: RE: issue-199 >> >> Shane, >> >> I have not missed key points, and know the DAA proposals mean >continued profiling, just think that needs to be made clear. Perhaps >you could give an example where applying a hash to a UID would be >useful. >> >> There is not much difference between the retention of a profile based >on algorithmically examining a web history and the actual web history >itself. Both can be a basis for discrimination. >> >> My point about verifiability is that without it, with only >administrative and operation controls, there will be inevitably be >demands for intrusive regulation, which will not be good for industry. >Verifiability is in fact quite easy to ensure if tracking is >constrained to cookies or even localStorage, and that is all the more >reason to rule out tracking by other means such as fingerprinting. >> >> Mike >> >> >> From: Shane Wiley [mailto:wileys@yahoo-inc.com] >> Sent: 10 July 2013 14:36 >> To: Mike O'Neill >> Cc: public-tracking@w3.org >> Subject: RE: issue-199 >> >> Mike, >> >> Perhaps you’ve not been on the calls as I believe you’ve missed a few >of the key points of this discussion. I won’t be able to provide a >full recount via email but I’ll try to hit the high points for you: >> >> 1. It’s understood obfuscation comes with some risk and will >need to be bundled with operational and administrative controls to >reach a reasonable confidence that data will not reverse engineered. >For example, data in the yellow state is not shared publically and/or >with parties where you don’t feel could protect the security of its >composition. While we’ve agreed on transparency in this area – no one >has requested external verifiability to date which I believe would be >somewhat impossible as a starting point. Perhaps something to work on >as a future goal (I believe the EFF would also be interested in >innovating techniques in this area – is that fair Lee?). >> 2. Aggregate scoring will result in a profile. The proposal >does not attempt to remove this concept but instead to ensure the >result doesn’t include a user’s historical cross-site activity. This >should not be confused with de-identification and instead is simply >another method to meet the goal of “not tracking”. >> >> - Shane >> >> From: Mike O'Neill [mailto:michael.oneill@baycloud.com] >> Sent: Wednesday, July 10, 2013 2:02 PM >> To: Shane Wiley >> Cc: public-tracking@w3.org >> Subject: RE: issue-199 >> >> Shane, >> >> As an example of why this “obfuscation” is pointless let it be a >simple substitution cypher so my UID (which happens to be “123456”) is >turned into “987654”. If I visit a website containing a reference to >adco.com that server recognises me because the UID contains “123456” >and builds up a profile about me. They apply the transform to the UID >and always get the unique value “987654”. which is stored in the >profiling dataset. When I visit other websites that also contain >references toadco.com the same process is repeated and my web activity >is appended to the dataset, again using “987654” as a key. >> >> It makes no difference how complex the UID transformation is, as >long as it is 1to1. >> >> Under the “DAA proposal” rules there is absolutely no diminution of >adco’s ability to profile me. >> >> If another party gets hold of the dataset they can also see my >profile, though not my original UID. If further records are shared they >can be connected to me by this other party because they have the same >“987654” UID. They may not be able to connect records containing >“123456” to me (unless they can crack the cypher or are given the key) >but what would be the point? If they have access to those data records >they can already profile me anyway. >> >> If activity data in the dataset, collected with my consent, contains >other PII about me, such as my name, post code, website history etc. >they should obfuscate that, perhaps using one way hash functions or >aggregated scoring algorithms. Since these datasets are a valuable >corporate asset you would expect them to be doing that anyway, but in >any case that is legally required in the EU. >> >> As the Snowden revelations have highlighted “operational and >administrative controls” need to be closely monitored. In the case of >security services this can be (has to be) through impeccable judicial >process under democratic oversight. This would not be appropriate for >commercial companies in a competitive environment, so transparent >technical procedures are necessary. >> >> The “yellow” state should be recognisable to users and others though >inspection of user agent data or web logs. >> >> Mike >> >> >> From: Shane Wiley [mailto:wileys@yahoo-inc.com] >> Sent: 10 July 2013 12:14 >> To: Mike O'Neill >> Cc: public-tracking@w3.org >> Subject: RE: issue-199 >> >> Mike, >> >> I respectfully disagree. Obfuscating the ID breaks the association >with the actual user/device. That said, I agree this has the risk of >being reversed so a blend of technical, operational, and administrative >controls must be brought to bear to keep this from occurring. >> >> De-identification doesn’t allow for profiling in a manner that could >affect a user’s experience (no way to get back to the user). >> >> Do Not Track can be achieved by breaking the link between a unique ID >and cross-site activity (URLs) – and this could result in a profile of >the user’s interest resulting from aggregate scoring – but this would >not allow a user’s historical activity to be retrieved. >> >> - Shane >> >> From: Mike O'Neill [mailto:michael.oneill@baycloud.com] >> Sent: Wednesday, July 10, 2013 11:55 AM >> To: Shane Wiley >> Cc: public-tracking@w3.org >> Subject: RE: issue-199 >> >> Hi Shane, >> >> How can it be possible to remove the association between a device and >a UID other than deleting it or ensuring it is deleted by the UA after >a short duration. If the UID is there (and present in every transport >level request if it is in a cookie) it uniquely points to the device >where it is stored or derived. This identity is available to the >receiving server as well as any actor with similar access to the data >stream or the same document origin. >> >> If you transform the UID in retained data by setting it to another >UID (say by using a hash function), this does not break the association >because there is a 1to1 mapping. There is no practical point in doing >it. >> >> De-identified data can only be classed as such if there is no >linkage. The “yellow” state can be imagined as an intermediate stage >before de-identification but is only relevant for permitted uses (such >as the detection of unique visitors for analytics or frequency >capping), and there is no need for it to exist for more than a few >hours. >> >> If we end up defining de-identified as including the ability to link >individuals to a profile it would be a travesty, and people will see >through it. The arms race has already started with an explosion of >blunt cookie and script blockers. If there is not a sensible response >to people’s real privacy concerns the usefulness of the web (and >consequently the profitability of many business models) will be >severely diminished. >> >> Mike >> >> >> From: Shane Wiley [mailto:wileys@yahoo-inc.com] >> Sent: 09 July 2013 19:30 >> To: Mike O'Neill; 'achapell'; npdoty@w3.org; tlr@w3.org >> Cc: public-tracking@w3.org; jeff@democraticmedia.org >> Subject: RE: issue-199 >> >> Mike, >> >> Deidentification is about removing the association between a unique >ID (any source: cookie, digital fingerprint, etc.) and the >actual/specific user/device. In this context: >> >> Red: actual user/device >> Yellow: not actual user/device but events are linkable (and only >usable for analytics/reporting) >> Green: not actual user/device and events are not linkable (outside >the scope of DNT) >> >> - Shane >> >> From: Mike O'Neill [mailto:michael.oneill@baycloud.com] >> Sent: Sunday, June 30, 2013 3:01 PM >> To: 'achapell'; npdoty@w3.org; tlr@w3.org >> Cc: public-tracking@w3.org; jeff@democraticmedia.org >> Subject: RE: issue-199 >> >> Alan, >> >> Persistent identifiers and their duration should be discussed as part >of the red/yellow/green permitted use debate. Browser fingerprinting >identifiers are qualitatively different from those stored in cookies or >localStorage because they are effectively infinite in duration, so I >thought it best to extend the defs. to make that clear. >> >> >> Mike >> >> >> From: achapell [mailto:achapell@chapellassociates.com] >> Sent: 30 June 2013 22:39 >> To: michael.oneill@baycloud.com; npdoty@w3.org; tlr@w3.org >> Cc: public-tracking@w3.org; jeff@democraticmedia.org >> Subject: RE: issue-199 >> >> Do we want to specify technologies here? >> >> >> Cheers, >> >> Alan Chapell >> 917 318 8440 >> >> >> >> -------- Original message -------- >> From: Mike O'Neill <michael.oneill@baycloud.com> >> Date: 06/30/2013 3:33 PM (GMT-05:00) >> To: Nicholas Doty <npdoty@w3.org>,tlr@w3.org >> Cc: public-tracking@w3.org,jeff@democraticmedia.org >> Subject: issue-199 >> >> Nick, Thomas >> >> Dr Dix’s letter reminded me that we need to have some reference to >browser fingerprinting being ruled out when DNT is set. I have amended >the definitions accordingly. >> >> Do you want me to modify the wiki? >> >> >> >> A persistent identifier is an arbitrary value held in, or derived >from other data in, the user agent whose purpose is to identify the >user agent in subsequent transactions to a particular web domain. It >may be encoded for example as the name or value attribute of an HTTP >cookie, as an item in localStorage or recorded in some way in the >cache. >> >> The duration of a persistent identifier is the maximum period of time >it will be retained in the user agent. This could be implemented for >example using the Expires or Max-Age attributes of an HTTP cookie so >that it is automatically deleted by the user agent after the specified >time period is exceeded. >> >> Browser fingerprinting is a method of tracking based on creating a >persistent identifier from other information either inherent in the >content request or already stored in the user agent. Such an identifier >may not need itself to be stored in the user-agent as it can be >calculated again in subsequent transactions. It follows from this that >its duration is effectively unlimited. >> >> Justification. >> >> With the duration definition, restrictions on permitted uses could >then be made that limit the duration of persistent identifiers. Because >browser fingerprinting cannot be given a finite duration this tracking >method should not be used when DNT is set even if it is for a permitted >use. In reality browser fingerprinting solely based on examining >initial content requests is usually not an effective tracking method >because the combination of IP addresses and other headers are not >sufficiently user specific, but we should rule out at least the more >complex form when DNT is set. >> >> Mike
Received on Wednesday, 10 July 2013 15:34:32 UTC