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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
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   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
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   described in the Simplified BSD License.




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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

































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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 <provide-location> 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"



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   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.






























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3.2.  Example

     <ruleset
         xmlns="urn:ietf:params:xml:ns:common-policy"
         xmlns:gp="urn:ietf:params:xml:ns:geolocation-policy"
         xmlns:ca="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr"
         xmlns:liar="urn:ietf:params:xml:ns:pidf:geopriv:liar">
       <rule id="drinking">
         <conditions>
           <identity>
             <one id="sip:wife@example.com"/>
           </identity>
           <gp:location-condition>
             <gp:location profile="civic-condition"
                          label="My Happy Place">
               <ca:civicAddress>
                 <ca:NAM>The Pub</ca:NAM>
               </ca:civicAddress>
             </gp:location>
           </gp:location-condition>
         </conditions>
         <actions/>
         <transformations>
           <gp:provide-location profile="replacement-transformation">
             <liar:liar>
               <ca:civicAddress>
                 <ca:NAM>Work</ca:NAM>
               </ca:civicAddress>
             </liar:liar>
           </gp:provide-location>
         </transformations>
       </rule>
     </ruleset>


















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4.  XML Schema

   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema targetNamespace="urn:ietf:params:xml:ns:geopriv:liar"
              xmlns:liar="urn:ietf:params:xml:ns:geopriv:liar"
              xmlns:xs="http://www.w3.org/2001/XMLSchema"
              elementFormDefault="qualified"
              attributeFormDefault="unqualified">

     <xs:element name="liar" type="liar:liarType"/>
     <xs:complexType name="liarType">
       <xs:complexContent>
         <xs:restriction base="xs:anyType">
           <xs:sequence>
             <!-- The content model is equivalent to that of
                  <location-info> in RFC 4119: very permissive -->
             <xs:any namespace="##any" processContents="lax"
                     minOccurs="0" maxOccurs="unbounded"/>
           </xs:sequence>
         </xs:restriction>
       </xs:complexContent>
     </xs:complexType>

   </xs: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).



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      XML:

         BEGIN
           <?xml version="1.0"?>
           <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
             "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
           <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
             <head>
               <title>Location Information Absolute Replacement</title>
             </head>
             <body>
               <h1>Namespace</h1>
               <h2>urn:ietf:params:xml:ns:geopriv:liar</h2>
   [[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX
       with the RFC number for this specification.]]
               <p>See <a href="[[RFC URL]]">RFCXXXX</a>.</p>
             </body>
           </html>
         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.



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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.











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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







































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