P3P - Platform for Privacy Preference

Barkha J. HermanFlorida Atlantic University

Introduction

W3C Emerging standardAllows users to control how personal info is used by web sitesUses XML and RDF to express policiesHTTP for transport

Background

Recommendation proposed by W3CIssue with usage of cookies / data

collection by web sites.Working group est. 1997.Specification 1.0 published April

2002Future – CC/PP, XML Signatures.

Why P3P?

Privacy - top concern of individualsPrivacy issues impeding growthEarly attempts on disclosure

lengthy and confusingNeed for consistency, simplicity,

transparencyGlobal solution for global market

What does it address?

Who is collecting this data? Exactly what information is being collected? For what purposes? Which information is being shared with others? And who are these data recipients? Can users make changes in how their data is used? How are disputes resolved? What is the policy for retaining data? And finally, where can the detailed policies be found in "human readable" form?

How does it work

Policies are expressed in XML – machine readable

Policies are transferred over HTTPRetrieval can be automatedPolicy verification is seamlessPrivacy Reports are viewable by

client – human readable

How does it work?

Enabling – Server side

Create a policy filePublish it in the default directory (/w3c/p3p.xml)Optionally, include reference in the HTTP headerOptionally, include compact notation in the http header

Enabling – Client side

User Agent checks for policyUser agent compares against set policyIf match, user agent gets page and displaysIf no match, page (or cookie) is rejectedUser Agent displays privacy report

P3P reference in http header

HTTP/1.1 200 OKDate: Wed, 17 Mar 2004 20:23:59 GMTServer: Apache/1.3.28 (Unix) PHP/4.2.3Content-Location: Overview.htmlVary: negotiate,acceptTCN: choiceP3P:

policyref="http://www.w3.org/2001/05/P3P/p3p.xml" Cache-Control: max-age=600Expires: Wed, 17 Mar 2004 20:33:59 GMT

Last-Modified: Tue, 16 Mar 2004 14:59:42 GMT

Compact notation in Http header

HTTP/1.0 200 OKDate: Wed, 17 Mar 2004 20:22:13 GMTContent-Length: 428Content-Type: text/htmlExpires: Wed, 17 Mar 2004 20:52:13 GMTCache-Control: max-age=1800Server: Microsoft-IIS/5.0P3P: CP="CAO CURa ADMa PSAo PSDo IVAo IVDo OUR

BUS PHY ONL PUR COM NAV INT DEM CNT STA PRE“IISExport: This web site was exported using IIS Export

v2.2Content-Location: http://www.oldnavy.com/taghtml

/default.html

Last-Modified: Tue, 03 Jun 2003 20:35:10

Example Policy File<?xml version="1.0" ?>

<POLICIES xmlns="http://www.w3.org/2002/01/P3Pv1">  <EXPIRY max-age="604800" /> <POLICY name="public"

discuri="http://www.w3.org/Consortium/Legal/privacy-statement#Public">

<ENTITY><DATA-GROUP>  <DATA ref="#business.name">World Wide Web Consortium</DATA>   <DATA ref="#business.contact-info.postal.name">MIT/LCS</DATA>   <DATA ref="#business.contact-info.postal.street">545 Technology

Square</DATA>   <DATA

ref="#business.contact-info.postal.postalcode">02143</DATA>   <DATA ref="#business.contact-info.postal.city">Cambridge

MA</DATA>   <DATA ref="#business.contact-info.postal.country">USA</DATA>   <DATA ref="#business.contact-info.postal.name">INRIA/Sophia

Antipolis</DATA>

…Continued  <DATA ref="#business.contact-info.postal.street">2004 Routes des

Lucioles</DATA>   <DATA ref="#business.contact-info.postal.postalcode">F-06902</DATA>   <DATA ref="#business.contact-info.postal.city">Sophia Antipolis</DATA>   <DATA ref="#business.contact-info.postal.country">FRANCE</DATA>   <DATA ref="#business.contact-info.postal.name">Keio University</DATA>   <DATA ref="#business.contact-info.postal.street">Shonan Fujisawa

Campus</DATA>   <DATA ref="#business.contact-info.postal.postalcode">252-8520</DATA>   <DATA ref="#business.contact-info.postal.city">5322 Endo, Fujisawa-shi,

Kanagawa</DATA>   <DATA ref="#business.contact-info.postal.country">JAPAN</DATA>   <DATA ref="#business.contact-info.online.email">site-policy@w3.org</DATA>   <DATA ref="#business.contact-info.telecom.telephone.intcode">1</DATA>   <DATA ref="#business.contact-info.telecom.telephone.loccode">617</DATA>   <DATA

ref="#business.contact-info.telecom.telephone.number">2532613</DATA>

…Continued  <DATA

ref="#business.contact-info.online.email">site-policy@w3.org</DATA>   <DATA ref="#business.contact-info.online.uri">http://www.w3.org/</DATA>   <DATA ref="#business.contact-info.telecom.telephone.intcode">1</DATA>   <DATA

ref="#business.contact-info.telecom.telephone.loccode">617</DATA>   <DATA ref="#business.contact-

info.telecom.telephone.number">2532613</DATA>   </DATA-GROUP>  </ENTITY><ACCESS>  <nonident /> </ACCESS><DISPUTES-GROUP><DISPUTES resolution-type="service" service="http://www.w3.org/" short-

description="site-policy@w3.org">  <LONG-DESCRIPTION>The Webmaster and our Communications Team will

carefully consider the input and correct errors. If you discover privacy invasive behavior, please don't hesitate to contact us.</LONG-DESCRIPTION>

…Continued <<IMG src="http://www.w3.org/Icons/WWW/w3c_home" width="72"

height="48" alt="Logo World Wide Web Consortium" /> <REMEDIES>  <correct />   </REMEDIES>  </DISPUTES>  </DISPUTES-

GROUP><STATEMENT>  <CONSEQUENCE>We collect normal Web-Logs. They are used for

Server administration, Web protocol research, Statistics of usage and Security.</CONSEQUENCE>

<PURPOSE>  <current />   <admin />   <develop />   </PURPOSE> <RECIPIENT>  <ours />   </RECIPIENT> <RETENTION>  <indefinitely />   </RETENTION> <DATA-GROUP>  <DATA ref="#dynamic.clickstream" />   <DATA ref="#dynamic.http.useragent" />   <DATA ref="#dynamic.http.referer" />   </DATA-GROUP>  </STATEMENT>  </POLICY>  </POLICIES>

User Agent support

IE 6.0 – supports compact notation only

Netscape 7.0 – complete support for 1.0

AT&T Privacy bird plugin – 1.0 support

Editors

P3PEditP3PEditorPrivacyBotPrivacy Policy Editor – web basedAlphaWorks P3P Editor

Validators

http://www.w3.org/P3P/validator.html

(only game in town)

APPEL – A P3P Preference Exchange Language 1.0 (APPEL1.0)

W3C working draft that specifies a language for describing sets of preferences about P3P policies.Rule-set for expressing P3P

<appel:RULE behavior="request" description="My Bank collects data only for itself and its agents"> <appel:REQUEST-GROUP>

<appel:REQUEST uri="http://www.my-bank.com/*"/> </appel:REQUEST-GROUP> <p3p:POLICY>

<p3p:STATEMENT> <p3p:RECIPIENT appel:connective="or-exact">

<p3p:ours/> </p3p:RECIPIENT> </p3p:STATEMENT>

</p3p:POLICY> </appel:RULE>

P3P vs. OPS

The Open Profiling Standard - proposal co-authored by Netscape, Firefly, and VeriSign. This specification proposed a means for the exchange of user profile information -- how to store and release, under the user's permission, data which is often requested or required by a Web site.Eventually, the P3P working groups decided not to include a data transfer protocol as part of P3Pv1.

P3P – Digital Signature assurance

W3C Note – Not a specificationThe design philosophy and requirements of this

specification are to:Define what it means for a P3P Policy to be assured via an XML Signature. Provide detached signatures for P3P Policies and Assurances.

Enveloping signatures MAY contain the P3P Policy Reference. This can be convenient in that all the files are included together, but this has the following two disadvantages: the Signature is the root element, and XPointer is required to select portions of the document.

Enveloped signatures are prohibited by P3P's content model.

Be concise and unambiguous.

Critiques

Weak on Company dataLack of EnforcementPolicy changes do not reflect

collected data

Future…

Version 1.x Allow policy choice Explicit agreement Non repudiation (DSig?)

CC/PP – now Device Independent WG Composite Capability Preference

Profiles