Geolocation Privacy

1. Geolocation Privacy Hannes Tschofenig International Working Group on Data Protection in Telecommunications Rome, March 2008

2. Acknowledgements • Thanks to Henning Schulzrinne, Jon Peterson, and Richard Barnes for their help with this slide set.

3. The IETF • 110+ working groups in 8 areas; security & privacy relevant topics in all these groups • Statistics about ongoing work: http://www.arkko.com/tools/docstats.html Internet Area General Area RAI Area O & M Area Applications Area Routing Area RAI Transport Area … AVT GEOPRIV SIPPING MMUSIC SIMPLE SIP Security Area

4. The GEOPRIV Working Group • First BoF on Spatial Location held at 48th IETF (July 2000) • IETF community had concerns that privacy was not sufficiently addressed • GEOPRIV WG formed, met for the first time at 50th IETF (August 2001) • Strong user privacy mandate in WG charter • Location determination methods are out of scope • Scope is on protecting the transmission of location information over the public Internet • 2008: A number of RFCs associated already available. • Participation from vendors, operators, standards professionals, policy experts, and academia • Challenging group with interesting individuals that produces a lot of mails. • More information:http://www.ietf.org/html.charters/geopriv-charter.html

5. Privacy Concerns • Location • Many entities know your location today • In many cases, YOU do not control the systems that determines and stores your location • Example: NetGeo database (see RFC 1876) • In many cases, location is only one data element in the larger presence context. Distribution of these other attributes also deserves privacy protection. • To understand the work in GEOPRIV the presence work has to be considered.

6. Overview of Presence • Presence emerged as a component of instant messaging applications • Foremost, provides binary availability data • Online or offline? • Closely tied to the concept of a friends list • Based on subscription, a persistent relationship • Modern presence systems also provide a disposition towards communication • Not just am I online, but am I busy, away, etc • Capability information • What kinds of communication can I accommodate with my endpoint? • Customized responses – context dependent • Give different answers to different subscribers

7. Basic Presence Model Notification (3) SUBSCRIBE (4) PUBLISH Publication Presence Server (5) NOTIFY Watcher Presentity (2) XCAP Policy Simplified SIP exchanges Rule Maker

8. Geopriv Real-time information, changing frequently Requires subscription model Use servers to enforce policy Need to be able to share information selectively Strong authentication & confidentiality model Extensibility (XML) required Presence Ditto Ditto Ditto Ditto Ditto Ditto Geolocation and Presence

9. Basic GEOPRIV Architecture Publication Notification Location Server Location Recipient Location Generator Policy Rules Rule Maker Shows only the network agents, not the human actors

10. GEOPRIV WG: Objectives • Pick location information XML language • Identify protocols conveying location information • Allow push model and subscription model • Select document format for location information • Provide strong security measures to protect location information in transit • Insert policy directives along with location information • Develop authorization policy languagefor restricting the distribution of location information • Third parties enforce policies on behalf of “rule maker” • Motivated by a concern that many producers of geolocation information will not be controlled by end users • Rule Maker may be the owner of the target device, or may not

11. GEOPRIV WG: Objectives • Pick location information XML language

12. XML Language for Location Information • The IETF did not want to define location information formats • Experts on these matters are largely elsewhere (Ignoring the work on DHCP geodetic location information…) • Instead, the IETF is focusing on architectures and tools for the secure distribution of location information documents • Defining an envelope to carry any XML-based location information format • Popular choice is Geographic Markup Language (GML) (from OCG) • http://www.opengeospatial.org/ • No suitable standardized format for civic location was available • Developed in Geopriv working group

13. GEOPRIV WG: Objectives • Identify protocols conveying location information • Allow push model and subscription model

14. Conveyance Protocols • Once you have a geolocation document, you need a protocol to carry it • Traditional protocols are applicable (like HTTP, etc) • Anything that can carry MIME types works • But a subscription model is ideal • Ability to track the location of a resource over time • Could use a polling model, but a subscription/notification model was deemed superior • Also, one-time fetch is desirable • Most of the work on location conveyance using SIP:http://tools.ietf.org/html/draft-ietf-sip-location-conveyance-10 A tiny tutorial can be found at: http://www.shingou.info/twiki/pub/EmergencyServices/EswAgenda2007/IETF-Emergency-Services-Tutorial.ppt

15. Example: Vehicle Tracking http://transport.wspgroup.fi/hklkartta/

16. GEOPRIV WG: Objectives • Select document format for location information • Provide strong security measures to protect location information in transit • Insert policy directives along with location information

17. PIDF-LO: RFC 4119 • Presence Information Data Format (PIDF) is an XML-based format for presence (RFC 3863) • Extends PIDF to accommodate two new elements: • Location-Info • Encapsulates location information • GML 3.0 <feature.xsd> schema (mandatory-to-implement) • Clarified by draft-ietf-geopriv-pdif-lo-profile • Supports civic location format (optional-to-implement) • Clarified by RFC 5139 • Usage-rules • Used to indicate privacy preferences

18. PIDF-LO: RFC 4119Basic Ruleset = Usage Restriction • MUST always be attached to a PIDF-LO document • Retention expires (how long are you allowed to keep the object) • Policy for retransmission of location information (Yes/No) • Reference to an external ruleset (optional) • A “note well” of free text, human readable privacy policy • Specified in RFC 4119

19. GEOPRIV WG: Objectives • Develop authorization policy languagefor restricting the distribution of location information • Third parties enforce policies on behalf of “rule maker” • Motivated by a concern that many producers of geolocation information will not be controlled by end users • Rule Maker may be the owner of the target device, or may not

20. Authorization for Presence and Location Information Authorization Framework Basic Ruleset Extended Ruleset Common Policy PIDF-LO Geopriv Policy Presence Policy RFC 4745 – Common Policy RFC 5020 -- Presence Authorization Policy draft-ietf-geopriv-policy-14.txt – Geolocation Policy

21. Extended RulesetCommon Policy • Design Goals: • Permit only • Additive permissions (“Minimal Disclosure”) • Upgradeable/Extensibility • Capability/Versioning support • No false assurance • Efficient implementation (no regular expressions) • Protocol-independent • Supports pluralism of contexts • Two Usage Models: • Attached (per-value or per-reference) to PIDF-LO document • Available at the Location/Presence Server • Identity information needs to be instantiated based on the specific conveyance protocol

22. Geopriv Policy • Adds location-based authorization policies to the Common Policy framework • Conditions: • IF **I am in the following area** THEN • Transformations: • SET usage policies • REDUCE granularity of provided location information

23. Presence Policy • Attributes mostly taken from Rich Presence Extensions to the Presence Information Data Format (RPID) • Conditions • Details identity usage for SIP • Actions • Subscription Handling (block, confirm, allow, polite block) • Transformations • Providing Access to Data Component Elements (device, person, service) • Providing Access to Presence Attributes • Provide Activities (e.g., appointment>, <breakfast>, <dinner>, <holiday>, <lunch>, <meal>, <meeting>, <performance>, <travel>, or <vacation>) • Provide Class • Provide DeviceID • Provide Mood (e.g., happy, angry, etc.) • Provide Place-is (e.g., noisy, quiet) • Provide Place-type (e.g., bus, ship, ..... RFC 4589) • Provide Privacy (e.g., audio, text, video) • Provide Relationship (e.g., family, friend) • Provide Sphere • Provide Status-Icon • Provide Time-Offset • Provide User-Input (e.g., idle) • Provide Note • Provide Unknown Attribute • Provide All Attributes

24. Principals Location Server LS Location Recipient LR Rule Holder RH Location Generator (LG) is a special role of a LS. Entity that initially injects LO into the system. Viewer is the final consumer of location information. The E2E StoryRecall the Basic Triangle Dissemination Channel [Request] LS LR LO Rules RH

25. The E2E Story Connecting Triangles LG Viewer LS LH LR LR LS LH LR LR LS LH LR LR LS LH `LR LR RH RH RH RH • Triangles can be combined to store and forward LOs • Logically forms a distribution tree • Branches when one LS provides same LO to multiple LRs • Root=LG, the entity that first determines the location of the target • Leaves=LRs, entities that consume location objects • Potentially many rule holders along this path • Target will usually be one of the rule holders • LG will usually be one of the rule holders

26. The E2E Story Assurances about the tree LG Viewer LS LH LR LR LS LH LR LR LS LH LR LR LS LH `LR LR RH RH RH RH • Critical parts of LO are unchanged • End-to-end privacy policy communication and enforcement • Rules are communicated down the tree by RH adding them to LO

27. Not Accomplished in GEOPRIV • Policy indication/negotiation in the style of P3P • Usage restriction policy usage beyond location information. • Make other SDOs to re-use usage restriction policies. • Extensions beyond presence (such as generic web services) Please give me access to your information. Here is my privacy policy! Presence Server OK. Based on your privacy policy you get access to X. Watcher

28. Challenge: User Interface • More work is necessary to develop user-friendly interfaces. • Particularly important since authorization policies are an integral part of the solution • A lot of today’s communication is still done without any policy handling. • Paradigm change since we see user in the role of changing the privacy policies (“user control and consent”).

29. Outlook • Increased usage of PUB/SUB usage and richer presence usage expected • As deployment increases the problems with data retention and privacy will increase too • GEOPRIV architecture unique among the standardization solutions. • More implementation work is needed to determine better and extended policy handling • Advertisement: Related area of interest is prevention of unwanted traffic. Identity management and authorization policies play an important role in this work as well. Will borrow a lot from the GEOPRIV concept. See http://www.shingou.info/bof-rucus.html