P3P - Platform for Privacy Preference

1
P3P - Platform for Privacy Preference

• Barkha J. Herman
• Florida Atlantic University

2
Introduction

• W3C Emerging standard
• Allows users to control how personal info is used
  by web sites
• Uses XML and RDF to express policies
• HTTP for transport

3
Background

• Recommendation proposed by W3C
• Issue with usage of cookies / data collection by
  web sites.
• Working group est. 1997.
• Specification 1.0 published April 2002
• Future CC/PP, XML Signatures.

4
Why P3P?

• Privacy - top concern of individuals
• Privacy issues impeding growth
• Early attempts on disclosure lengthy and
  confusing
• Need for consistency, simplicity, transparency
• Global solution for global market

5
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?

6
How does it work

• Policies are expressed in XML machine readable
• Policies are transferred over HTTP
• Retrieval can be automated
• Policy verification is seamless
• Privacy Reports are viewable by client human
  readable

7
How does it work?

8
Enabling Server side

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

9
Enabling Client side

• User Agent checks for policy
• User agent compares against set policy
• If match, user agent gets page and displays
• If no match, page (or cookie) is rejected
• User Agent displays privacy report

10
P3P reference in http header

• HTTP/1.1 200 OK
• Date Wed, 17 Mar 2004 202359 GMT
• Server Apache/1.3.28 (Unix) PHP/4.2.3
• Content-Location Overview.html
• Vary negotiate,accept
• TCN choice
• P3P policyref"http//www.w3.org/2001/05/P3P/p3p.
  xml"
• Cache-Control max-age600
• Expires Wed, 17 Mar 2004 203359 GMT
• Last-Modified Tue, 16 Mar 2004 145942 GMT

11
Compact notation in Http header

• HTTP/1.0 200 OK
• Date Wed, 17 Mar 2004 202213 GMT
• Content-Length 428
• Content-Type text/html
• Expires Wed, 17 Mar 2004 205213 GMT
• Cache-Control max-age1800
• Server Microsoft-IIS/5.0
• P3P 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 v2.2
• Content-Location http//www.oldnavy.com/taghtml/d
  efault.html
• Last-Modified Tue, 03 Jun 2003 203510

12
Example Policy File

• lt?xml version"1.0" ?gt
• ltPOLICIES xmlns"http//www.w3.org/2002/01/P3Pv1"gt
  
•   ltEXPIRY max-age"604800" /gt
• ltPOLICY name"public" discuri"http//www.w3.org/C
  onsortium/Legal/privacy-statementPublic"gt
• ltENTITYgt
• ltDATA-GROUPgt
•   ltDATA ref"business.name"gtWorld Wide Web
  Consortiumlt/DATAgt
•   ltDATA ref"business.contact-info.postal.name"gtM
  IT/LCSlt/DATAgt
•   ltDATA ref"business.contact-info.postal.street"
  gt545 Technology Squarelt/DATAgt
•   ltDATA ref"business.contact-info.postal.postalc
  ode"gt02143lt/DATAgt
•   ltDATA ref"business.contact-info.postal.city"gtC
  ambridge MAlt/DATAgt
•   ltDATA ref"business.contact-info.postal.country
  "gtUSAlt/DATAgt
•   ltDATA ref"business.contact-info.postal.name"gtI
  NRIA/Sophia Antipolislt/DATAgt

13
Continued

•   ltDATA ref"business.contact-info.postal.street"
  gt2004 Routes des Lucioleslt/DATAgt
•   ltDATA ref"business.contact-info.postal.postalc
  ode"gtF-06902lt/DATAgt
•   ltDATA ref"business.contact-info.postal.city"gtS
  ophia Antipolislt/DATAgt
•   ltDATA ref"business.contact-info.postal.country
  "gtFRANCElt/DATAgt
•   ltDATA ref"business.contact-info.postal.name"gtK
  eio Universitylt/DATAgt
•   ltDATA ref"business.contact-info.postal.street"
  gtShonan Fujisawa Campuslt/DATAgt
•   ltDATA ref"business.contact-info.postal.postalc
  ode"gt252-8520lt/DATAgt
•   ltDATA ref"business.contact-info.postal.city"gt5
  322 Endo, Fujisawa-shi, Kanagawalt/DATAgt
•   ltDATA ref"business.contact-info.postal.country
  "gtJAPANlt/DATAgt
•   ltDATA ref"business.contact-info.online.email"gt
  site-policy_at_w3.orglt/DATAgt
•   ltDATA ref"business.contact-info.telecom.teleph
  one.intcode"gt1lt/DATAgt
•   ltDATA ref"business.contact-info.telecom.teleph
  one.loccode"gt617lt/DATAgt
•   ltDATA ref"business.contact-info.telecom.teleph
  one.number"gt2532613lt/DATAgt

14
Continued

•   ltDATA ref"business.contact-info.online.email"gt
  site-policy_at_w3.orglt/DATAgt
•   ltDATA ref"business.contact-info.online.uri"gtht
  tp//www.w3.org/lt/DATAgt
•   ltDATA ref"business.contact-info.telecom.teleph
  one.intcode"gt1lt/DATAgt
•   ltDATA ref"business.contact-info.telecom.teleph
  one.loccode"gt617lt/DATAgt
•   ltDATA ref"business.contact-info.telecom.teleph
  one.number"gt2532613lt/DATAgt
•   lt/DATA-GROUPgt
•   lt/ENTITYgt
• ltACCESSgt
•   ltnonident /gt
• lt/ACCESSgt
• ltDISPUTES-GROUPgt
• ltDISPUTES resolution-type"service"
  service"http//www.w3.org/" short-description"si
  te-policy_at_w3.org"gt
•   ltLONG-DESCRIPTIONgtThe 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.lt/LONG-DESCRIPTIONgt

15
Continued

•  ltltIMG src"http//www.w3.org/Icons/WWW/w3c_home"
  width"72" height"48" alt"Logo World Wide Web
  Consortium" /gt
• ltREMEDIESgt  ltcorrect /gt   lt/REMEDIESgt 
  lt/DISPUTESgt  lt/DISPUTES-GROUPgt
• ltSTATEMENTgt
•   ltCONSEQUENCEgtWe collect normal Web-Logs. They
  are used for Server administration, Web protocol
  research, Statistics of usage and
  Security.lt/CONSEQUENCEgt
• ltPURPOSEgt  ltcurrent /gt   ltadmin /gt   ltdevelop /gt
    lt/PURPOSEgt
• ltRECIPIENTgt  ltours /gt   lt/RECIPIENTgt
  ltRETENTIONgt  ltindefinitely /gt
•   lt/RETENTIONgt ltDATA-GROUPgt
•   ltDATA ref"dynamic.clickstream" /gt
•   ltDATA ref"dynamic.http.useragent" /gt
•   ltDATA ref"dynamic.http.referer" /gt
•   lt/DATA-GROUPgt
•   lt/STATEMENTgt
•   lt/POLICYgt
•   lt/POLICIESgt

16
User Agent support

• IE 6.0 supports compact notation only
• Netscape 7.0 complete support for 1.0
• ATT Privacy bird plugin 1.0 support

17
Editors

• P3PEdit
• P3PEditor
• PrivacyBot
• Privacy Policy Editor web based
• AlphaWorks P3P Editor

18
Validators

• http//www.w3.org/P3P/validator.html
• (only game in town)

19
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
• ltappelRULE behavior"request" description"My
  Bank collects data only for itself and its
  agents"gt
• ltappelREQUEST-GROUPgt
• ltappelREQUEST uri"http//www.my-bank.com/"/gt
  
• lt/appelREQUEST-GROUPgt
• ltp3pPOLICYgt
• ltp3pSTATEMENTgt
• ltp3pRECIPIENT appelconnective"or-exact"gt
  ltp3pours/gt lt/p3pRECIPIENTgt
• lt/p3pSTATEMENTgt
• lt/p3pPOLICYgt
• lt/appelRULEgt

20
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.

21
P3P Digital Signature assurance

• W3C Note Not a specification
• The 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.

22
Critiques

• Weak on Company data
• Lack of Enforcement
• Policy changes do not reflect collected data

23
Future

• Version 1.x
• Allow policy choice
• Explicit agreement
• Non repudiation (DSig?)
• CC/PP now Device Independent WG
• Composite Capability Preference Profiles