Privacy Authorization Languages

1
Privacy Authorization Languages

• Week 7 - October 10, 12

2
Privacy languages serve many roles

• Specify organizations privacy policy to end
  users and their agents
• Specify users privacy preferences to users
  agent
• Specify organizations privacy policy to
  gatekeeper server that can approve or deny
  requests to access database
• Specify policy associated with particular data
  elements to parties that buy or rent data

3
Can one privacy language do it all?

• Maybe
• But so far none have emerged
• Weve found over a dozen privacy languages
  (including several access control and rule
  languages used for privacy applications)
• Languages have different audiences, specify
  policies at different levels of granularity, and
  have different strengths and weaknesses

4
User privacy preferences

• P3P 1.0 agents may (optionally) take action based
  on user preferences
• Users should not have to trust privacy defaults
  set by software vendors
• User agents that can read APPEL (A P3P Preference
  Exchange Language) files can offer users a number
  of canned choices developed by trusted
  organizations
• Preference editors allow users to adapt existing
  preferences to suit own tastes, or create new
  preferences from scratch
• For more info on APPEL see http//www.w3.org/TR/WD
  -P3P-preferences or Chapter 13 in Web Privacy
  with P3P

5
APPEL rule

• ltappelRULE behavior"limited" prompt"yes"
• description"Warning! Data may be shared."gt
• ltp3pPOLICYgt
• ltp3pSTATEMENTgt
• ltp3pRECIPIENT appelconnective"or" gt
• ltp3psame/gt
• ltp3pother-recipient/gt
• ltp3ppublic/gt
• ltp3punrelated/gt
• lt/p3pRECIPIENTgt
• lt/p3pSTATEMENTgt
• lt/p3pPOLICYgt
• lt/appelRULEgt

description
connective- or- and- non-or- non-and-
and-exact- or-exact
pattern
Behavior- request- block- limited
6
What does this APPEL ruleset do?

• ?lt?xml version"1.0"?gt
• ltappelRULESET xmlnsappel"http//www.w3.org/20
  01/02/APPELv1"
• xmlnsp3phttp//www.w3.org/2000/12/P3Pv1
  crtdby"Lorrie Cranor" gt
• ltappelRULE behavior"limited"
  descriptionWHAT DOES IT DO?" gt
• ltp3pPOLICY gt
• ltp3pSTATEMENT gt
• ltp3pPURPOSE appelconnective"or"gt
• ltp3pcontact required"opt-out" /gt
• ltp3ptelemarketing required"opt-out"
  /gt
• ltp3pcontact required"always" /gt
• ltp3ptelemarketing required"always"
  /gt
• lt/p3pPURPOSEgt
• lt/p3pSTATEMENTgt
• lt/p3pPOLICYgt
• lt/appelRULEgt
• ltappelRULE behavior"request" gt
• ltappelOTHERWISE /gt
• lt/appelRULEgt

7
APPEL question in HW7

• What are your personal privacy preferences?
• a) First express them in English as a set of 3 to
  5 rules. For example one rule might be "I don't
  want companies to share my data." If you can't
  capture all of your privacy preferences in 5
  rules, just write down the 5 rules you consider
  most important.
• b) Translate your rules into P3P vocabulary
  elements (for example, the above rule would
  translate to "RECIPIENTours")
• c) Create an APPEL ruleset that represents your
  set of 3 to 5 privacy preference rules (plus a
  catch-all rule)

8
Microsoft privacy template language

• See Appendix D of Web Privacy with P3P
• http//msdn.microsoft.com/library/default.asp?url
  /workshop/security/privacy/overview/privacyimportx
  ml.asp
• Specifies rules for user agents to handle various
  types of cookies
• Based on P3P compact policy tokens
• Allows policies for specific web sites

9
Microsoft example

• ltMSIEPrivacygtltMSIEPrivacySettings
  formatVersion"6"gt
• ltp3pCookiePolicy zone"internet"gt
• ltfirstParty noPolicyDefault"reject"
  noRuleDefault"accept" alwaysAllowSession"yes"gt
• ltif expr"TEL" action"reject"gtlt/ifgt
• ltif expr"FIN,CON" action"forceSession"gtlt/i
  fgt
• ltif expr"FIN,CONa" action"forceSession"gtlt/
  ifgt
• ltif expr"GOV,PUB" action"forceSession"gtlt/i
  fgt
• lt/firstPartygt
• ltthirdParty noPolicyDefault"accept"
  noRuleDefault"accept" alwaysAllowSession"yes"gt
• lt/thirdPartygt
• lt/p3pCookiePolicygt
• ltalwaysReplayLegacy/gt
• lt/MSIEPrivacySettingsgt
• ltMSIESiteRules formatVersion"6"gt
• ltsite domain"www.BlueYonderAirlines.com"
• action"accept"gt
• lt/sitegt
• lt/MSIESiteRulesgtlt/MSIEPrivacygt

10
EPAL

• Enterprise Privacy Authorization Language
• Developed by IBM, submitted to W3C
• Allows enterprises to develop granular rules to
  check whether data access is authorized
• Similar to P3P syntax but not identical
• Includes
• Data-categories
• User-categories - administrators, doctors, etc.
• Purposes
• Actions - disclose, read, etc.
• Obligations - delete after 30 days, get consent,
  etc.
• Conditions - user category doctor
• Allow and deny rules
• http//www.w3.org/Submission/2003/SUBM-EPAL-200311
  10/

11
Announcements

• Bring laptop (with wireless card if possible) to
  class on Wednesday
• Project proposal due Oct 19
• Homework 7/8 due Oct 26

12
Homework 4 Discussion

• http//lorrie.cranor.org/courses/fa05/hw4.html
• Privacy software reviews
• Why do sites use web bugs?

13
Homework 5 Discussion

• http//lorrie.cranor.org/courses/fa05/hw5.html
• Similarities and differences of P3P user agents
• What did you like or dislike about them?
• Experience creating bank P3P policies