Privacy Policy, Law and Technology Carnegie Mellon University Fall 2005 Lorrie Cranor 1 Privacy Authorization Languages Week 7 - October 10, 12

Privacy Policy, Law and Technology Carnegie Mellon University Fall 2005 Lorrie Cranor 2 Privacy languages serve many roles Specify organization’s privacy policy to end users and their agents Specify users’ privacy preferences to users’ agent Specify organization’s 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

Privacy Policy, Law and Technology Carnegie Mellon University Fall 2005 Lorrie Cranor 3 Can one privacy language do it all? Maybe… But so far none have emerged We’ve 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

Privacy Policy, Law and Technology Carnegie Mellon University Fall 2005 Lorrie Cranor 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 or Chapter 13 in Web Privacy with P3P

Privacy Policy, Law and Technology Carnegie Mellon University Fall 2005 Lorrie Cranor 5 APPEL rule <appel:RULE behavior="limited" prompt="yes" description="Warning! Data may be shared."> Behavior - request - block - limited description connective - or - and - non-or - non-and - and-exact - or-exact pattern

Privacy Policy, Law and Technology Carnegie Mellon University Fall 2005 Lorrie Cranor 6 What does this APPEL ruleset do? <appel:RULESET xmlns:appel=" xmlns:p3p= crtdby="Lorrie Cranor" >

Privacy Policy, Law and Technology Carnegie Mellon University Fall 2005 Lorrie Cranor 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 "RECIPIENT=ours") c) Create an APPEL ruleset that represents your set of 3 to 5 privacy preference rules (plus a catch-all rule)

Privacy Policy, Law and Technology Carnegie Mellon University Fall 2005 Lorrie Cranor 8 Microsoft privacy template language See Appendix D of Web Privacy with P3P ty/privacy/overview/privacyimportxml.asp ty/privacy/overview/privacyimportxml.asp Specifies rules for user agents to handle various types of cookies Based on P3P compact policy tokens Allows policies for specific web sites

Privacy Policy, Law and Technology Carnegie Mellon University Fall 2005 Lorrie Cranor 9 Microsoft example <site domain=" action="accept">

Privacy Policy, Law and Technology Carnegie Mellon University Fall 2005 Lorrie Cranor 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

Privacy Policy, Law and Technology Carnegie Mellon University Fall 2005 Lorrie Cranor 11 Announcements Bring laptop (with wireless card if possible) to class on Wednesday Project proposal due Oct 19 Homework 7/8 due Oct 26

Privacy Policy, Law and Technology Carnegie Mellon University Fall 2005 Lorrie Cranor 12 Homework 4 Discussion Privacy software reviews Why do sites use web bugs?

Privacy Policy, Law and Technology Carnegie Mellon University Fall 2005 Lorrie Cranor 13 Homework 5 Discussion Similarities and differences of P3P user agents What did you like or dislike about them? Experience creating bank P3P policies