GEOPRIV M. Thomson Internet-Draft Commscope Intended status: Informational June 29, 2011 Expires: December 31, 2011 A Privacy-Preserving Policy Transformation for Location draft-thomson-geopriv-lying-00.txt Abstract Obscuring location effectively is difficult. Falsehood offers a simpler, more effective method of location privacy protection. A mechanism is defined whereby a rule maker can request that a location server lie about location. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on December 31, 2011. Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Thomson Expires December 31, 2011 [Page 1] Internet-Draft Lying About Location June 2011 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions used in this document . . . . . . . . . . . . . . . 3 3. Location Information Absolute Replacement . . . . . . . . . . . 3 3.1. Interaction with Other Transformations . . . . . . . . . . 4 3.2. Example . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 6.1. URN Sub-Namespace Registration for urn:ietf:params:xml:ns:geopriv:liar . . . . . . . . . . . . 6 6.2. XML Schema Registration for Location Information Absolute Replacement Schema . . . . . . . . . . . . . . . . 7 6.3. Location Transformation Token Registration . . . . . . . . 7 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 8. Informative References . . . . . . . . . . . . . . . . . . . . 8 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 8 Thomson Expires December 31, 2011 [Page 2] Internet-Draft Lying About Location June 2011 1. Introduction Obscuring location has applications for protecting privacy, as described in [I-D.ietf-geopriv-policy]. Effectively protecting privacy through obscuring location information is difficult. Given an obscured location and enough supplementary information, a location recipient can recover a great deal of information about the known location despite obfuscation being used. This supplementary information might include data on geographic features and their characteristics, past behavior of the target or aggregated data. Solving the difficult obscuring problem might be possible, but the effort required to try is significant. A more expedient solution to the overall problem is to provide a way for a rule maker to select the location that is reported to location recipients. This privacy solution presents a trade-off. While finer control is thereby given to rule makers over the location information that is shared, it also presents a greater burden on the rule maker developing policy rules. An extension to the element defined in [I-D.ietf-geopriv-policy] is described. This policy extension is most useful where an automated system generates location information. In systems where the rule maker already is presented with an opportunity to alter location information, such as where the rule maker role is assumed by the entity generating (e.g. [RFC5985]) or publishing (e.g. [RFC3903]) location, such a mechanism is redundant. 2. Conventions used in this document Familiarity with the terminology outlined in [I-D.ietf-geopriv-arch] is helpful. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 3. Location Information Absolute Replacement The location information absolute replacement ("liar") element is a transformation element that is included in the "provide-location" Thomson Expires December 31, 2011 [Page 3] Internet-Draft Lying About Location June 2011 element of a policy document. When a "liar" element is included, the "profile" attribute MUST be set to "replacement-transformation". The "liar" element can contain any form of location information that is valid for the "location-info" element in a PIDF-LO [RFC4119] (see also [RFC5491]). In order to apply the transformation, replace the content of any selected "location-info" element in the presence document with the content of the "liar" element in the policy document. Content is copied verbatim. 3.1. Interaction with Other Transformations The common policy [RFC4745] framework permits the application of policy rules in any order. Precedence is used to determine which transformation is finally applied. When combining multiple "provide-location" transformations, the location information absolute replacement transformation is assigned the highest available precedence. Thomson Expires December 31, 2011 [Page 4] Internet-Draft Lying About Location June 2011 3.2. Example The Pub Work Thomson Expires December 31, 2011 [Page 5] Internet-Draft Lying About Location June 2011 4. XML Schema 5. Acknowledgements Richard Barnes provided input on the original idea. 6. IANA Considerations This section registers an XML schema for the location information absolute replacement element, the corresponding namespace and "replacement-transformation" token. 6.1. URN Sub-Namespace Registration for urn:ietf:params:xml:ns:geopriv:liar This section registers a new XML namespace, "urn:ietf:params:xml:ns:geopriv:liar", as per the guidelines in [RFC3688]. URI: urn:ietf:params:xml:ns:geopriv:liar Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org), Martin Thomson (martin.thomson@commscope.com). Thomson Expires December 31, 2011 [Page 6] Internet-Draft Lying About Location June 2011 XML: BEGIN Location Information Absolute Replacement

Namespace

urn:ietf:params:xml:ns:geopriv:liar

[[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX with the RFC number for this specification.]]

See RFCXXXX.

END 6.2. XML Schema Registration for Location Information Absolute Replacement Schema This section registers an XML schema as per the guidelines in [RFC3688]. URI: urn:ietf:params:xml:schema:geopriv:liar Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org), Martin Thomson (martin.thomson@commscope.com). Schema: The XML for this schema can be found in Section 4 of this document. 6.3. Location Transformation Token Registration The token "replacement-transformation" is registered in the Geolocation Policy Location Profile Registry, as defined in [I-D.ietf-geopriv-policy]. This token is used for the "provide-location" element as described in Section 3. 7. Security Considerations Policy documents include privacy-sensitive information. The additional capabilities added by this document do not change this fact, but expand the possibilities for embarassment if policy documents are revealed. Thomson Expires December 31, 2011 [Page 7] Internet-Draft Lying About Location June 2011 8. Informative References [I-D.ietf-geopriv-arch] Barnes, R., Lepinski, M., Cooper, A., Morris, J., Tschofenig, H., and H. Schulzrinne, "An Architecture for Location and Location Privacy in Internet Applications", draft-ietf-geopriv-arch-03 (work in progress), October 2010. [I-D.ietf-geopriv-policy] Schulzrinne, H., Tschofenig, H., Morris, J., Cuellar, J., and J. Polk, "Geolocation Policy: A Document Format for Expressing Privacy Preferences for Location Information", draft-ietf-geopriv-policy-23 (work in progress), March 2011. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004. [RFC3903] Niemi, A., "Session Initiation Protocol (SIP) Extension for Event State Publication", RFC 3903, October 2004. [RFC4119] Peterson, J., "A Presence-based GEOPRIV Location Object Format", RFC 4119, December 2005. [RFC4745] Schulzrinne, H., Tschofenig, H., Morris, J., Cuellar, J., Polk, J., and J. Rosenberg, "Common Policy: A Document Format for Expressing Privacy Preferences", RFC 4745, February 2007. [RFC5491] Winterbottom, J., Thomson, M., and H. Tschofenig, "GEOPRIV Presence Information Data Format Location Object (PIDF-LO) Usage Clarification, Considerations, and Recommendations", RFC 5491, March 2009. [RFC5985] Barnes, M., "HTTP-Enabled Location Delivery (HELD)", RFC 5985, September 2010. Thomson Expires December 31, 2011 [Page 8] Internet-Draft Lying About Location June 2011 Author's Address Martin Thomson Commscope Andrew Building (39) Wollongong University Campus Northfields Avenue Wollongong, NSW 2522 AU Phone: +61 2 4221 2915 Email: martin.thomson@commscope.com Thomson Expires December 31, 2011 [Page 9]