1. Enhancing Web Privacy Protection Through Declarative Policies
Pranam Kolari1
Li Ding1, Lalana Kagal2, Shashi Ganjugunte1, Anupam Joshi1, Tim Finin1 1 2
Pranam Kolari – Policy 2005

2. Outline Web Privacy P3P/APPEL Motivation and Problem Description
User Trust
Rei Policy Language
System Design
Privacy Policy Specification
Conclusion
Pranam Kolari – Policy 2005

3. Cathy on the Web Source : Cathy Guisewite via Lorrie Cranor
Pranam Kolari – Policy 2005

4. Cathy on the Web Source : Cathy Guisewite via Lorrie Cranor
Pranam Kolari – Policy 2005
Source : Cathy Guisewite via Lorrie Cranor

5. P3P – The current solution
P3P is Platform for Privacy Preferences
Protocols and specification languages
P3P Schema for Websites
APPEL Schema for Clients
Pranam Kolari – Policy 2005

6. P3P Sample Policy
Site’s name and contact info
Access disclosure
Statement
Human-readable explanation
How data may be used
Data recipients
Data retention policy
Types of data collected
<POLICIES xmlns="
<POLICY discuri="
name="policy">
<ENTITY>
<DATA-GROUP>
<DATA
</DATA>
ref="#business.contact-info.online.uri">
<DATA ref="#business.name">Web Privacy With P3P</DATA>
</DATA-GROUP>
</ENTITY>
<ACCESS><nonident/></ACCESS>
<STATEMENT>
<CONSEQUENCE>We keep standard web server logs.</CONSEQUENCE>
<PURPOSE><admin/><current/><develop/></PURPOSE>
<RECIPIENT><ours/></RECIPIENT>
<RETENTION><indefinitely/></RETENTION>
<DATA ref="#dynamic.clickstream"/>
<DATA ref="#dynamic.http"/>
</STATEMENT>
</POLICY>
</POLICIES>
Pranam Kolari – Policy 2005
Slide Courtesy: Lorrie Cranor

7. APPEL
APPEL is A P3P Preference Exchange Language (W3C working draft in April 2002)
Website P3P Policy
APPEL User Preference
<RULESET>
<RULE behavior=“request”>
<POLICY>
<STATEMENT>
<PURPOSE><individual-decision/></PURPOSE>
<RECIPIENT><ours/></RECIPIENT>
</STATEMENT>
</POLICY>
</RULE> …
</RULESET> …
<STATEMENT>
<PURPOSE>< individual-decision /></PURPOSE>
<RECIPIENT><ours/></RECIPIENT>
</STATEMENT>
Pranam Kolari – Policy 2005

8. The problem …
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9. Trusting Websites
56% of consumers don’t believe businesses keep promises
63% believe independent verification is important
62% believe existing laws and organizational practices are insufficient
Consumer Confidence
Trust website policies
Distrust website policies
Source : (Ernst and Young report 2004)
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10. Existing Mechanisms
A4Proxy
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11. P3P/XPref APPEL User Preference Website P3P Policy
<RULESET>
<RULE behavior=“request”>
<POLICY>
<STATEMENT>
<PURPOSE><individual-decision/></PURPOSE>
<RECIPIENT><ours/></RECIPIENT>
</STATEMENT>
</POLICY>
</RULE> …
</RULESET> …
<STATEMENT>
<PURPOSE>< individual-decision /></PURPOSE>
<RECIPIENT><ours/></RECIPIENT>
</STATEMENT>
<PURPOSE>< telemarketing /></PURPOSE>
<RECIPIENT><third-party/></RECIPIENT>
<RULESET>
<RULE behavior=“request”
condition=“/POLICY[
every $pname in STATEMENT/PURPOSE/*
satisfies name($panme)=“individual-decision”
and
every $rname in STATEMENT/RECIPIENT/*
satisfies name($rname)= “ours”
]”/>
<RULE behavior=“block” condition=“true”/>
</RULESET>
XPref User Preference
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12. Low P3P Adoption
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13. Problem Description
P3P policies published by websites not trusted by users
Low P3P adoption impedes client adoption by users
The languages available to describe user privacy preferences are not sufficiently expressive
P3P framework does not provide a coherent view of available privacy protection mechanisms to the user
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14. Our approach …
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15. Social Recommendations (1, 2)
Note: Superscripts signify problem being addressed
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16. Website Evaluation Ontology (1, 2)
Modeling User Perspective of Trust
Populating ontology with instance data
BizRate
Services for users to explicitly specify preferences
Share using existing social network mechanisms (Ding 2003)
Website Evaluation Ontology
popularity
serviceType 9
DiscussionGroup
hasP3P
owner
URI
OSDN
hasPrivacyCertifier
isBasedOutOf
USA --
hasTextPolicy
domainSuffix
URI
org
OSDN US
policySimilarTo
lawEnforcedBy
Yes
hasPolicyEnforcement
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17. Rei Policy Language (3)(4)
Rei, a policy specification language developed
by Lalana Kagal at UMBC (lkagal 2003)
Encoded in (1) Prolog, (2) OWL
Models deontic concepts of permissions, prohibitions, obligations and dispensations
Uses meta policies for conflict resolution
Uses speech acts for dynamic policy modification
We used it as a policy specification language
RDF specification capability (matches that of P3P)
Dynamic Policies as future extension to our work
Pranam Kolari – Policy 2005
Part content Courtesy: Lalana Kagal

18. Rei Policy Language (3)(4)
actor, target
Entity
DeonticObject to
action
deontic
grants
Policy
Granting
Action
precondition, effect
requirement
SpeechAct
DomainAction
context
Constraint
Boolean
Simple
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19. Rei Policy Modeling (1)(2)(3)(4)
Two actors
Website
Web browser
Multiple context
P3P RDF published by websites
User Context
Trust Recommendations
Multiple actions with priorities
Right, Prohibition, Obligation*
Pranam Kolari – Policy 2005
*(not enforced)

20. System Design (1)(2)(3)(4)
Key Points
Web Sites optionally publish P3P policies
Clients specify privacy preferences using a policy language - Rei
Privacy Expert is the privacy enhancement enabler by binding together entities of the system
Rei Engine evaluates policies of users against website attributes
Website Recommender Network propagates and builds a model of websites based on reputation
FOAF – Enables the creation of the website recommender network 1
Web Server
publish (optionally)
Website
Recommender
Network
P3P Policy
Ontologies, Trust rules
Personal agents
XSLT Transformer 5 3
Rei Engine
Privacy Expert 4
JRC Privacy Proxy* 6
FOAF
Rei Privacy Policy
(RDF based, enhancements
over APPEL)
Trusted Agent
Network#
Clients
publish 2
# FOAF, Golbeck, Li ideas of Trust
Pranam Kolari – Policy 2005

21. Example Policy [1] - Template
<policy:Policy rdf:about="&wwwpolicy;comprehensive“ policy:desc="Sample policy">
<policy:grants rdf:resource="&wwwpolicy;grantingPermission" /> ..
</policy:Policy>
<!– Granting Objects -->
<policy:Granting rdf:about="&wwwpolicy;grantingPermission">
<policy:desc>Current policy allows access to a website</policy:desc>
<policy:to rdf:resource="&wwwpolicy;var1"/>
<policy:deontic rdf:resource="&wwwpolicy;right1"/>
</policy:Granting> …
<!– Deontic Objects -->
<deontic:Permission rdf:about="&wwwpolicy;right1">
<deontic:actor rdf:resource="&wwwpolicy;var1"/>
<deontic:action rdf:resource="&wwwpolicy;request"/>
<deontic:constraint rdf:resource="&wwwpolicy;complexconstraint" />
</deontic:Permission>
Policy Rule
Rule Desc.
Rule Actor
Rule Action
Policy Constraint
Pranam Kolari – Policy 2005

22. Example Policy [1] - Constraints
<constraint:SimpleConstraint rdf:about=“&wwwpolicy;domainOfServiceConstraint”
constraint:subject =“&wwwpolicy;var1”
constraint:predicate=“&wwwpolicy;domainOfServiceConstraint”
constraint:object=“&weo;travel” />
<constraint:SimpleConstraint rdf:about=“&wwwpolicy;trustedDomainGOVconstraint”
constraint:predicate=“&weo;domainSuffix”
constraint:object=“&weo;gov” /> …
<constraint:Or rdf:about=“&wwwpolicy;complexconstraint”>
<constraint:first rdf:resource=“&wwwpolicy;trustedDomainGOVconstraint” />
<constraint:second rdf:resource=“&wwwpolicy;domainOfServiceConstraint” />
</constraint:Or>
Policy Constraint
Policy Constraint
Pranam Kolari – Policy 2005

23. Example Policy [2] - Obligation
<policy:Policy rdf:about="&wwwpolicy;obligationexample"
<policy:grants rdf:resource="&wwwpolicy;grantingRight" />
<policy:grants rdf:resource="&wwwpolicy;grantingObligation"/> …
</policy:Policy>
<policy:Granting rdf:about="&wwwpolicy;grantingRight">
<policy:deontic rdf:resource="&wwwpolicy;right1"/>
</policy:Granting>
<policy:Granting rdf:about="&wwwpolicy;grantingObligation">
<policy:to rdf:resource="&wwwpolicy;webbrowser"/>
<policy:deontic rdf:resource="&wwwpolicy;obligation1"/> ..
<deontic:Permission rdf:about="&wwwpolicy;right1">
<deontic:actor rdf:resource="&wwwpolicy;website"/>
<deontic:action rdf:resource="&wwwpolicy;request"/>
</deontic:Permission>
<deontic:Obligation rdf:about="&wwwpolicy;obligation1">
<deontic:actor rdf:resource="&wwwpolicy;webbrowser"/>
<deontic:action rdf:resource="&wwwpolicy;tunnelRequest"/>
</deontic:Obligation>
Right
Obligation
Pranam Kolari – Policy 2005

24. Example Policy [3] - Priority
<policy:Policy rdf:about="&wwwpolicy;rulepriorityexample“>
<policy:defaultModality rdf:resource=”&metapolicy;NegativeModalityPrecedence/>
<policy:grants rdf:resource="&wwwpolicy;grantingRight1" />
<policy:grants rdf:resource="&wwwpolicy;grantingRight2" />
<policy:grants rdf:resource="&wwwpolicy;grantingProhibition" />
<metapolicy:rulePriority rdf:resource="&wwwpolicy;rulepriority1"/> …
</policy:Policy>
<metapolicy:RulePriority rdf:about=“&wwwpolicy;rulepriority1”>
<metapolicy:ruleOfGreaterPriority rdf:resource=“&wwwpolicy;grantingRight1” />
<metapolicy:ruleOfLesserPriority rdf:resource=“&wwwpolicy;grantingProhibition” />
</metapolicy:RulePriority>
Default
Rules
Explicit
Pranam Kolari – Policy 2005

25. Closing Remarks Evaluation of trust based recommender systems
Web browser adopting enhanced framework
clients with FOAF based spam filtering
Policy Engines
User Context Manager
Ontologies from the Semantic Web
Development of common shared ontologies for user trust and context – FOAF, SOUPA
Pranam Kolari – Policy 2005

26. Conclusion
The utility of an existing policy language in a highly complex policy engineering domain
Policy engineering and enforcement in Web Privacy offers many challenges
Enforcing Obligations
Engineering Delegation Logic using Speech Acts and subsequent enforcement
Pranam Kolari – Policy 2005

27. Questions ?? Paper and Presentation Available at:
Pranam Kolari – Policy 2005