draft-ietf-geopriv-reqs-02.txt   draft-ietf-geopriv-reqs-03.txt 
Internet Draft J. Cuellar Internet Draft Jorge Cuellar
Document: draft-ietf-geopriv-reqs-02.txt Siemens AG Document: draft-ietf-geopriv-reqs-03.txt Siemens AG
John B. Morris, Jr. John B. Morris, Jr.
Center for Democracy and Technology Center for Democracy and Technology
D. Mulligan Deirdre Mulligan
Samuelson Law, Technology, and Public Policy Clinic Samuelson Law, Technology, and Public Privacy Clinic
Expires in six months Jan 2003 Jon Peterson
NeuStar
James Polk
Cisco
Expires in six months Mar 2003
Geopriv requirements Geopriv requirements
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
skipping to change at line 44 skipping to change at line 50
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved. Copyright (C) The Internet Society (2001). All Rights Reserved.
Abstract Abstract
Location-based services, navigation applications, emergency Location-based services, navigation applications, emergency
services, management of equipment in the field, and other location- services, management of equipment in the field, and other location-
dependent services need geographic location information about a dependent services need geographic location information about a
Cuellar, Morris, Mulligan, Peterson, Polk 1
Geopriv Requirements Mar 2003
Target (such as a user, resource or other entity). There is a need Target (such as a user, resource or other entity). There is a need
to securely gather and transfer location information for location to securely gather and transfer location information for location
services, while at the same time protecting the privacy of the services, while at the same time protecting the privacy of the
individuals involved. individuals involved.
Cuellar, Morris, Mulligan 1 This document focuses on the authorization, security and privacy
Geopriv Requirements Jan 2003
This document focuses on the authorization, integrity and privacy
requirements for such location-dependent services. Specifically, it requirements for such location-dependent services. Specifically, it
describes the requirements for the geopriv Location Object (used to describes the requirements for the Geopriv Location Object (LO) and
securely transfer location data and other privacy-enabling for the protocols that use this Location Object. This LO is
information) and for the protocols that use this Location Object. envisioned to be the main object defined by the Geopriv WG, used in
all Geopriv exchanges and in particular used to securely transfer
location data.
Table of Contents Table of Contents
1. Overview........................................................3 1. Overview.......................................................3
2. Conventions used in this document...............................4 2. Conventions used in this document..............................4
3. Terminology.....................................................4 3. Glossary.......................................................4
3.1. Foundational Definitions...................................4 4. Primary Geopriv Entities.......................................6
3.1.1. Location Information (LI) and Sighting................4 5. Further Geopriv Terminology....................................7
3.1.2. The Location Object...................................6 5.1. Location Information and Sighting.........................7
3.1.3. Location Object vs. Using Protocol....................6 5.2. The Location Object and Using Protocol....................8
3.1.4. Trusted vs. Non-trusted Data Flows....................6 5.3. Trusted vs. Non-trusted Data Flows........................9
3.2. Geopriv Entities and Functions.............................7 5.4. Further Geopriv Principals...............................10
3.2.1. Primary Geopriv Entities..............................7 5.5. Privacy Rules............................................12
3.2.2. Secondary Geopriv Entities............................8 5.6. Identifiers, Authentication and Authorization............12
3.2.3. Geopriv Data Storage Functions........................9 6. Scenarios and Explanatory Discussion..........................13
3.3. Privacy Policies and Rules.................................9 7. Requirements..................................................17
3.4. Identifiers, Authentication and Authorization.............10 7.1. Location Object..........................................17
4. Scenarios and Explanatory Discussion...........................11 7.2. The Using Protocol.......................................19
4.1. Scenarios of Data Flow....................................11 7.3. Rule based Location Data Transfer........................20
5. Requirements...................................................14 7.4. Location Object Privacy and Security.....................21
5.1. Location Object...........................................15 7.4.1. Identity Protection.................................21
5.2. The Using Protocol........................................16 7.4.2. Authentication Requirements.........................21
5.3. Policy based Location Data Transfer.......................17 7.4.3. Actions to be secured...............................21
5.4. Location Object Privacy and Security......................18 7.5. Non-Requirements.........................................22
5.5. Identity Protection.......................................18 8. Security Considerations.......................................22
5.6. Authentication Requirements...............................18 8.1. Traffic Analysis.........................................22
5.7. Actions to be secured.....................................18 8.2. Securing the Privacy Rules...............................22
5.8. Non-Requirements..........................................19 8.3. Emergency Case...........................................23
6. Security Considerations........................................19 8.4. Identities and Anonymity.................................23
6.1. Traffic Analysis..........................................19 8.5. Unintended Target........................................24
6.2. Securing the Privacy Policies.............................19 9. Protocol and LO Issues for later Consideration................24
6.3. Emergency Case............................................20 9.1. Multiple Locations in one LO.............................24
6.4. Identities and Anonymity..................................20 9.2. Translation Fields.......................................24
6.5. Unintended Target.........................................21 9.3. Truth Flag...............................................25
7. Acknowledgements...............................................21 9.4. Timing Information Format................................25
8. References.....................................................21
9. Protocol and LO Issues for later Consideration.................22
9.1. Multiple Locations in one LO..............................22
9.2. Translation Fields........................................22
9.3. Specifying Desired Accuracy in a Request..................22
9.4. Truth Flag................................................22
Cuellar, Morris, Mulligan 2 Cuellar, Morris, Mulligan, Peterson, Polk 2
Geopriv Requirements Jan 2003 Geopriv Requirements Mar 2003
9.5. Timing Information Format.................................22 9.5. The Name Space of Identifiers............................25
9.6. The Name Space of Identifiers.............................22 10. Acknowledgements.............................................25
10. Author's Addresses............................................23 11. References...................................................25
11. Full Copyright Statement......................................23 12. Author's Addresses...........................................26
13. Full Copyright Statement.....................................27
1. Overview 1. Overview
Location-based services (applications that require geographic Location-based services (applications that require geographic
location information as input) are becoming increasingly common. location information as input) are becoming increasingly common.
The collection and transfer of location information about a The collection and transfer of location information about a
particular Device and/or Target can have important privacy particular Target can have important privacy implications. A key
implications. A key goal of the protocols described in this goal of the protocol described in this document is to facilitate the
document is to facilitate the protection of privacy pursuant to protection of privacy pursuant to Privacy Rules set by the
privacy policies set by the "user" (or, more precisely in the "user/owner of the Target" (or, more precisely in the terminology of
terminology of this document defined in Section 3 below, the "Rule this document given in Section 3 and 5.4 below, the "Rule Maker").
Maker").
The ability to derive or compute a Device's location, and access to The ability to gather and generate a Target's location, and access
the derived or computed location, are key elements of the location- to the derived or computed location, are key elements of the
based services privacy equation. Central to a Target's privacy are location-based services privacy equation. Central to a Target's
(a) the identity of entities that have access to raw location data, privacy are (a) the identity of entities that have access to raw
derive or compute location, and/or have access to derived or location data, derive or compute location, and/or have access to
computed location information, and (b) whether those entities can be derived or computed location information, and (b) whether those
trusted to know and follow the privacy policy of the user. entities can be trusted to know and follow the Privacy Rules of the
user.
The main principles guiding the requirements described in this The main principles guiding the requirements described in this
document are: document are:
1) Security of the transmission of Location Object is essential to 1) Security of the transmission of Location Object is essential to
guarantee the integrity and confidentiality of the location guarantee the integrity and confidentiality of the location
information. This includes authenticating the sender and information. This includes authenticating the sender and
receiver of the Location Object, and securing the Location Object receiver of the Location Object, and securing the Location Object
itself. itself.
2) A critical role is played by user-controlled policies, which 2) A critical role is played by user-controlled Privacy Rules, which
describe the restrictions imposed or permissions given by the describe the restrictions imposed or permissions given by the
"user" (or, as defined below, the "Rule Maker"). The policies "user" (or, as defined below, the "Rule Maker"). The Privacy
specify the necessary conditions that allow a Location Server to Rules specify the necessary conditions that allow a Location
forward Location Information to a Location Recipient, and the Server to forward Location Information to a Location Recipient,
conditions under which and purposes for which the Location and the conditions under which and purposes for which the
Information can be used. Location Information can be used.
3) The Location Object should be able to carry a limited but core 3) One type of Privacy Rules specify in particular how location
set of privacy policies. The exact form or expressiveness of information should be filtered, depending on who the recipient
policies in the core set or in the full set is not further is. Filtering is the process of reducing the precision or
discussed in this paper, but is discussed more extensively in a resolution of the data. A typical rule may be of the form: "my
separate document. location can only be disclosed to the owner of such credentials
in such precision or resolution" (e.g., "my co-workers can be
told the city I am currently in").
4) Whenever appropriate, the location information should not be Cuellar, Morris, Mulligan, Peterson, Polk 3
linked to the real identity of the user or a static identifier Geopriv Requirements Mar 2003
easily linked back to the real identity of the user (e.g., the
phone number). Rather, the user should be able to specify which
Cuellar, Morris, Mulligan 3 4) The Location Object should be able to carry a limited but core
Geopriv Requirements Jan 2003 set of Privacy Rules. The exact form or expressiveness of those
Rules in the core set or in the full set is not further discussed
in this document, but will be discussed more extensively in
future documents produced by this working group.
5) Whenever appropriate, the location information should not be
linked to the real identity of the user or a static identifier
easily linked back to the real identity of the user (i.e.,
Personally Identifiable Information such as a name, mailing
address, phone number, social security number, or email address
or username). Rather, the user should be able to specify which
local identifier, unlinked pseudonym, or private identifier is to local identifier, unlinked pseudonym, or private identifier is to
be bound to the location information. be bound to the location information.
5) The user may want to hide the real identities of himself and his 6) The user may want to hide the real identities of himself and his
partners not only to eavesdroppers but also to other entities partners not only to eavesdroppers but also to other entities
participating in the protocol. participating in the protocol.
Although complete anonymity may not be appropriate for some Although complete anonymity may not be appropriate for some
applications because of legal constraints or because some location applications because of legal constraints or because some location
services may in fact need explicit identifications, in most cases services may in fact need explicit identifications, in most cases
the location services only need some type of authorization the location services only need some type of authorization
information and/or perhaps anonymous identifiers of the entities in information and/or perhaps anonymous identifiers of the entities in
question. question.
2. Conventions used in this document 2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in [RFC2119]. this document are to be interpreted as described in [RFC2119].
Note that the requirements discussed here are requirements on the Note that the requirements discussed here are requirements on the
generic Location Object and on the using protocols for location generic Location Object and on the using protocols for location
services. Thus the requirements discussed in this document mostly services. Thus, for the most part, the requirements discussed in
refer to the capabilities that are mandatory-to-implement. For this document refer to capabilities that are mandatory-to-implement.
example, requiring that implementations support integrity is not the For example, requiring that implementations support integrity is not
same thing as requiring that all protocol traffic be authenticated. the same thing as requiring that all protocol traffic be
In other cases, the requirement may be that the user always obtains authenticated. In contrast, an example of a mandatory-to-use (not
a notice when his location data was not authenticated. This practice just mandatory-to-implement) requirement might be one that states
is mandatory-to-use, not just to implement. that the user always receives a notice when his location data was
not authenticated. This practice is mandatory-to-use, not just to
implement.
3. Terminology 3. Glossary
The terminology and definitions detailed below include both (1) For easy reference and readability, below are basic terms that will
terms used in the requirements section of this document, and (2) be defined more formally and fully later in this document.
terms that provide additional detail about the usage model
envisioned for the geopriv Location Object. These latter terms will
be utilized in a separate scenarios document.
3.1. Foundational Definitions Location Generator (LG): The entity that initially determines or
gathers the location of the Target and creates Location
Objects describing the location of the Target.
3.1.1. Location Information (LI) and Sighting Cuellar, Morris, Mulligan, Peterson, Polk 4
Geopriv Requirements Mar 2003
The focus of the geopriv working group is on information about a Location Object (LO): An object conveying location information
(and possibly privacy rules) to which Geopriv security
mechanisms and privacy rules are to be applied.
Location Recipient (LR): The entity that receives location
information. It may have asked for this location explicitly
(by sending a query to a location server), or it may receive
this location asynchronously.
Location Server (LS): The entity to which a LG publishes location
objects, the recipient of queries from location receivers, and
the entity that applies rules designed by the rule maker.
Precision: The number of significant digits to which a value has
been reliably measured.
Principal: The holder/subject of the credentials, e.g. a
workstation user or a network server.
Resolution: The fineness of detail that can be distinguished in
measured area. Applied to Geopriv this means the fineness of
area within provided, and closed, borders (ex. Latitude and
Longitude boundaries).
Rule Holder: The entity that provides the rules associated with a
particular target for the distribution of location
information. It may either ępushĘ rules to a location server,
or a location server may ępullĘ rules from the Rule Holder.
Rule Maker: The authority that creates rules governing access to
location information for a target (typically, this it the
target themselves).
Rule, or Privacy Rule: A directive that regulates an entity's
activities with respect to location information, including the
collection, use, disclosure, and retention of location
information.
Target: A person or other entity whose location is communicated
by a Geopriv Location Object.
Using Protocol: A protocol that carries a Location Object.
Viewer: A Principal that consumes location information that is
communicated by a Geopriv Location Object, but does not pass
this information further.
Resolution and Precision are very close terms. Either quality can
be 'reduced' to coarsen location information: 'resolution' by
defining a off-center perimeter around a user's location or
Cuellar, Morris, Mulligan, Peterson, Polk 5
Geopriv Requirements Mar 2003
otherwise enlarging the area in consideration (from state to
country, say) and 'precision' by discarding significant digits of
positioning information (rounding off longitude and latitude from
seconds to minutes, say). Another WG document treats this topic in
much more detail.
4. Primary Geopriv Entities
The following picture shows the primary Geopriv entities in a simple
and basic architecture, without claim of completeness nor any
suggestion that the entities identified must in all cases be
physically separate entities.
+----------+
| Rule |
| Holder |
| |
+----+-----+
|
rule|interface
V
+----------+ +----------+ +----------+
|Location | publication | Location | notification |Location |
|Generator +-------------->| Server +-------------->|Recipient |
| | interface | | interface | |
+----------+ +----------+ +----------+
The four primary Entities are described as follows:
Location Generator (LG): The entity that initially determines or
gathers the location of the Target and creates Location
Objects describing that location. LGs publish Location
Objects to Location Servers. The manner in which the Location
Generator learns of Location Information is outside the scope
of the Geopriv Protocol..
Location Server (LS): The LS is an element that receives
publications of Location Objects from Location Generators and
may receive subscriptions from Location Recipients. The LS
applies the rules (which it learns from the Rule Holder) to
LOs it receives from LGs, and then notifies LRs of resulting
LOs as necessary.
Location Recipient (LR): The LR is an element that receives
notifications of Location Objects from Location Servers. The
LR may render these LOs to a user or automaton in some
fashion.
Cuellar, Morris, Mulligan, Peterson, Polk 6
Geopriv Requirements Mar 2003
Rule Holder (RH): The RH is an element that houses Privacy Rules
for receiving, filtering and distributing Location Objects for
specific Targets. A LS may query an RH for a set of rules, or
rules may be pushed from the RH to an LS. The rules in the
Rule Holder are populated by the Rule Maker.
Thus Location Generation is the process of gathering Location
Information, perhaps from multiple sources, at an IP-based Geopriv
Entity, the LG, which communicates with other Geopriv Entities.
Rules MUST be authenticated and protected. How this is done and in
particular how to distribute the keys to the RM and other
authorities is outside of the scope of this document. See also
Section 8.2 "Securing the Privacy Rules".
The interfaces between the Geopriv entities are not necessarily
protocol interfaces; they could be internal interfaces within a
single composed device. In some architectures, the Location
Generator, Rule Holder, and Location Server might all be implemented
in the same device. There may be several Rule Holders that enforce
the Privacy Rules at a particular Location Server.
5. Further Geopriv Terminology
The terminology and definitions detailed below include both terms
that, besides the primary Geopriv entities, (1) are used in the
requirements section of this document, and (2) provide additional
detail about the usage model envisioned for the Geopriv Location
Object. These latter terms will be utilized in a separate scenarios
document and elsewhere.
5.1. Location Information and Sighting
The focus of the Geopriv working group is on information about a
Target's location that is NOT based on generally or publicly Target's location that is NOT based on generally or publicly
available sources, but instead on private information provided or available sources, but instead on private information provided or
created by a Target, a Target's Device, or a Target's network or created by a Target, a Target's Device, or a Target's network or
service provider: service provider. Notwithstanding this focus on private location
information, the Geopriv Location Object could certainly be used to
Location Information (LI): convey location information from publicly available sources.
A relatively specific way of describing where a Device is
located and that is (a) derived or computed from information
generally not available to the general public (such as
Cuellar, Morris, Mulligan 4 Location Information: A relatively specific way of describing
Geopriv Requirements Jan 2003 where a Device is located.
information mainly available to a network or service This Location Information may have determined in many different
provider), (b) determined by a Device that may be not ways, including:
generally publicly addressable or accessible, or (c) input or (a) derived or computed from information generally not available to
the general public (such as information mainly available to a
network or service provider), (b) determined by a Device that may be
not generally publicly addressable or accessible, or (c) input or
otherwise provided by a Target. otherwise provided by a Target.
As examples, LI could include (a) information calculated by Cuellar, Morris, Mulligan, Peterson, Polk 7
triangulating on a wireless signal with respect to cell phone Geopriv Requirements Mar 2003
towers, (b) longitude and latitude information determined by a
Device with GPS (global positioning satellite) capabilities, or (c) As examples, the Location Information could include (a) information
information manually entered into a cell phone or laptop by a Target calculated by triangulating on a wireless signal with respect to
in response to a query. cell phone towers, (b) longitude and latitude information determined
by a Device with GPS (global positioning satellite) capabilities,
(c) information manually entered into a cell phone or laptop by a
Target in response to a query, or (d) automatically delivered by
some other IP protocol, such as at device configuration via DHCP.
Excluded from this definition is the determination of location Excluded from this definition is the determination of location
information wholly without the knowledge or consent of the Target information wholly without the knowledge or consent of the Target
(or the Target's network or access service provider), based on (or the Target's network or access service provider), based on
generally available information such as an IP or e-mail address. In generally available information such as an IP or e-mail address. In
some cases information like IP address can enable someone to some cases information like IP address can enable someone to
estimate (at least roughly) a location. Commercial services exist estimate (at least roughly) a location. Commercial services exist
that offer to provide rough location information based on IP that offer to provide rough location information based on IP
address. Currently, this type of location information is typically address. Currently, this type of location information is typically
less accurate and has a coarser granularity than the type of less precise than the type of location information addressed in this
location information addressed in this document. Although this type document. Although this type of location computation still raises
of location computation still raises significant potential privacy significant potential privacy and public privacy concerns, such
and public policy concerns, such scenarios are generally outside the scenarios are generally outside the scope of this document.
scope of this document.
Within any given location-based transaction, the INITIAL Within any given location-based transaction, the INITIAL
determination of location (and thus the initial creation of Location determination of location (and thus the initial creation of Location
Information) is termed a Sighting: Information) is termed a Sighting:
Sighting: Sighting:
The initial determination of location based on non-public The initial determination of location based on non-public
information (as discussed in the definition of Location information (as discussed in the definition of Location
Information), and the initial creation of Location Information), and the initial creation of Location
Information. Information.
skipping to change at line 263 skipping to change at line 419
(Identifier, Location) (Identifier, Location)
where Identifier is the identifier assigned to a Target being where Identifier is the identifier assigned to a Target being
sighted, and Location is the current position of that Target being sighted, and Location is the current position of that Target being
sighted. Not all entities may have access to exactly the same piece sighted. Not all entities may have access to exactly the same piece
of sighting information. A sighting may be transformed to a new of sighting information. A sighting may be transformed to a new
sighting pair: sighting pair:
(Identifier-1, Location-1) (Identifier-1, Location-1)
before it is provided by a Location Sighter or Location Server to before it is provided by a Location Generator or Location Server to
another Location Recipient (for instance, another Location Server). Location Recipient. In this case, Identifier-1 may be Pseudonym,
and Location-1 may have less precision or resolution than the
Cuellar, Morris, Mulligan 5 original value.
Geopriv Requirements Jan 2003
In this case, Identifier-1 may be Pseudonym, and Location-1 may have 5.2. The Location Object and Using Protocol
less accuracy or granularity than the original value.
3.1.2. The Location Object Cuellar, Morris, Mulligan, Peterson, Polk 8
Geopriv Requirements Mar 2003
A main goal of the geopriv working group is to define a Location A main goal of the Geopriv working group is to define a Location
Object (LO), to be used to convey both Location Information and Object (LO), to be used to convey both Location Information and
basic privacy-protecting instructions: basic privacy-protecting instructions:
Location Object (LO): This data contains the Location Information Location Object (LO): This data contains the Location Information
of the Target, and other fields including an identity or of the Target, and other fields including an identity or
pseudonym of the Target, time information, core privacy pseudonym of the Target, time information, core Privacy Rules,
policies, authenticators, etc. Most of the fields are authenticators, etc. Most of the fields are optional,
optional, including the Location Information itself. including the Location Information itself.
Nothing is said about the semantics of a missing field. For Nothing is said about the semantics of a missing field. For
instance, a partially filled object MAY be understood implicitly as instance, a partially filled object MAY be understood implicitly as
the request to complete it. Or, if no time information is included, the request to complete it. Or, if no time information is included,
this MAY implicitly mean "at the current time" or "at a very recent this MAY implicitly mean "at the current time" or "at a very recent
time", but it could be interpreted in a different way, depending on time", but it could be interpreted in a different way, depending on
the context. the context.
3.1.3. Location Object vs. Using Protocol The "using protocol" is the protocol that uses (reads or modifies)
the Location Object. A protocol that just transports the LO as a
The "using protocol" is the protocol that uses (creates, reads or string of bits, without looking at them (like an IP storage protocol
modifies) the Location Object. A protocol that just transports the could do), is not a using protocol, but only a transport protocol.
LO as a string of bits, without looking at them (like an IP storage Nevertheless, the entity or protocol that caused the transport
protocol could do), is not a using protocol, but only a transport protocol to move the LO is responsible for the appropriate
protocol. Nevertheless, the entity or protocol that caused the distribution, protection, usage, retention, and storage of the LO
transport protocol to move the LO is responsible of the correct based on the rules that apply to that LO.
distribution, protection, usage, retention, and storage of the LO.
The security and privacy enhancing mechanisms used to protect the LO The security and privacy enhancing mechanisms used to protect the LO
are of two types: First, the Location Object definition MUST are of two types: First, the Location Object definition MUST
include (optional) fields or mechanisms used to secure the LO as include the fields or mechanisms used to secure the LO as such. The
such. The LO MAY be secured, for example, using cryptographic LO MAY be secured, for example, using cryptographic checksums or
checksums or encryption as part of the LO itself. Second, the using encryption as part of the LO itself. Second, the using protocol may
protocol may also provide security mechanisms to securely transport also provide security mechanisms to securely transport the Location
the Location Object. Object.
The security mechanisms of the Location Object itself are to be When defining the LO, the design should observe that the security
preferred. mechanisms of the Location Object itself are to be preferred. Thus
the definition of the LO MUST include some minimal crypto
functionality (Req. 14 and 15). Moreover, if the RM specifies the
use of a particular LO security mechanism, it MUST be used (Req. 4).
3.1.4. Trusted vs. Non-trusted Data Flows 5.3. Trusted vs. Non-trusted Data Flows
Location information can be used in very different environments. In Location information can be used in very different environments. In
some cases the participants will have longstanding relationships, some cases the participants will have longstanding relationships,
while in others participants may have discrete interactions with no while in others the participants may have discrete interactions with
prior contractual or other contact. no prior contractual or other contact.
The different relationships raise different concerns for the The different relationships raise different concerns for the
implementation of privacy rules, including the need to communicate implementation of privacy rules, including the need to communicate
Privacy Rules. A public Rule Holder, for example, may be
unnecessary in a trusted environment where more efficient methods of
Cuellar, Morris, Mulligan 6 Cuellar, Morris, Mulligan, Peterson, Polk 9
Geopriv Requirements Jan 2003 Geopriv Requirements Mar 2003
privacy policies. A public Rule Repository, for example, may be
unnecessary in a trusted environment where more efficient methods of
addressing privacy issues exist. The following terms distinguish addressing privacy issues exist. The following terms distinguish
between the two basic types of data flows: between the two basic types of data flows:
Trusted Data Flow: Trusted Data Flow:
A data flow that is governed by a pre-existing contractual A data flow that is governed by a pre-existing contractual
relationship that addresses location privacy. relationship that addresses location privacy.
Non-trusted Data Flow: Non-trusted Data Flow:
The data flow is not governed by a pre-existing contractual The data flow is not governed by a pre-existing contractual
relationship that addresses location privacy. relationship that addresses location privacy.
3.2. Geopriv Entities and Functions 5.4. Further Geopriv Principals
The entities of a geopriv application or transaction may be given
explicit roles:
3.2.1. Primary Geopriv Entities
Certain entities and roles are involved in most (and in some cases
all) geopriv transactions:
Target: Target:
The entity whose location is desired by the Location Seeker. The entity whose location is desired by the Location
In many cases the Target will be the human "user" of a Device Recipient. In many cases the Target will be the human "user"
or an object such as a vehicle or shipping container to which of a Device or an object such as a vehicle or shipping
the Device is attached. In some instances the Target will be container to which the Device is attached. In some instances
the Device itself. the Target will be the Device itself.
Device: Device:
The technical device the location of which is tracked as a The technical device the location of which is tracked as a
proxy for the location of a Target. A Device might, for proxy for the location of a Target.
example, be a cell phone, a Global Positioning Satellite (GPS)
receiver, a laptop equipped with a wireless access Device, or
a transmitter that emits a signal that can be tracked or
located. In some situations, such as when a Target manually
inputs location information (perhaps with a web browser), the
Target is effectively performing the function of a Device.
Rule Maker: A Device might, for example, be a cell phone, a Global Positioning
Satellite (GPS) receiver, a laptop equipped with a wireless access
Device, or a transmitter that emits a signal that can be tracked or
located. In some situations, such as when a Target manually inputs
location information (perhaps with a web browser), the Target is
effectively performing the function of a Device.
Rule Maker (RM):
The individual or entity that has the authorization to set the The individual or entity that has the authorization to set the
applicable privacy policies and rules. In many cases this applicable Privacy Rules for a potential Geopriv Target. In
will be the owner of the Device, and in other cases this may many cases this will be the owner of the Device, and in other
be the user who is in possession of the Device. For example, cases this may be the user who is in possession of the Device.
parents may control what happens to the location information For example, parents may control what happens to the location
derived from a child's cell phone. A company, in contrast, may information derived from a child's cell phone. A company, in
own and provide a cell phone to an employee but permit the contrast, may own and provide a cell phone to an employee but
employee to set the privacy rules. permit the employee to set the privacy rules.
Cuellar, Morris, Mulligan 7 There are four scenarios in which some form of constraint or
Geopriv Requirements Jan 2003 override might be placed on the Privacy Rules of the Rule
Maker:
Location Seeker (LSeek): 1. In the case of emergency services (such as E911 within the
An individual or entity who seeks to receive location data United States), local or national laws may require that
about a Target. accurate location information be transmitted in certain
defined emergency call situations. The Geopriv Working Group
MUST facilitate this situation.
A Location Seeker may act in one or more of the following more Cuellar, Morris, Mulligan, Peterson, Polk 10
specialized roles: as the Location Sighter, a Location Server, or as Geopriv Requirements Mar 2003
an Ultimate Location Recipient:
Location Sighter (LoSi), or Location Data-Source 2. In the case of legal interception, the RM may not be aware
The original source of the sighting of a Target in a given of an override directive imposed by a legal authority. It is
transaction. not the expectation of the Working Group that particular
accommodation will be made to facilitate this situation.
Location Server (LServ), or Intermediate Location Recipient: 3. In the context of an employment relationship or other
A Device or entity that provides access to Location contractual relationship, the owner of a particular location
Information (possibly after processing or altering it) in (such as a corporate campus) may impose constraints on the use
accordance with the privacy policies of the Rule Maker. Some of Privacy Rules by a Rule Maker. It is not the expectation
location tracking scenarios may involve a Target, Device, or of the Working Group that particular accommodation will be
Device user performing the function of a Location Server. made to facilitate this situation.
Ultimate Location Recipient (ULR): 4. It is conceivable that a governmental authority may seek to
impose constraints on the use of Privacy Rules by a Rule
Maker in non-emergency situations. It is not the expectation
of the Working Group that particular accommodation will be
made to facilitate this situation.
Viewer:
An individual or entity who receives location data about a An individual or entity who receives location data about a
Target and does not transmit the location information or Target and does not transmit the location information or
information based on the Target's location (such as driving information based on the Target's location (such as driving
directions to or from the Target) to any party OTHER than the directions to or from the Target) to any party OTHER than the
Target or the Rule Maker. Target or the Rule Maker.
3.2.2. Secondary Geopriv Entities
Certain entities and functions are present or involved in only a
subset of geopriv transactions:
Data Transporter: Data Transporter:
An entity or network that receives and forwards data without An entity or network that receives and forwards data without
processing or altering it. A Data Transporter could processing or altering it. A Data Transporter could
theoretically be involved in almost any transmission between a theoretically be involved in almost any transmission between a
Device and a Location Server, a Location Server and a second Device and a Location Server, a Location Server and a second
Location Server, or a Location Server and an Ultimate Location Location Server, or a Location Server and an Viewer. Some
Recipient. Some location tracking scenarios may not involve a location tracking scenarios may not involve a Data
Data Transporter. Transporter.
Initial Access Provider (IAP): Access Provider (AP):
The entity that provides the initial network access or other The domain that provides the initial network access or other
data communications services essential for the operation of data communications services essential for the operation of
communications functions of the Device or computer equipment communications functions of the Device or computer equipment
in which the Device operates. Often, the IAP -- which will be in which the Device operates. Often, the AP -- which will be
a wireless carrier, an Internet Service Provider, or an a wireless carrier, an Internet Service Provider, or an
internal corporate network -- will be identical to the LoSi. internal corporate network -- contains the LG. Sometimes the
In other cases the IAP has a "dumb" LoSi, one that transmits AP has a "dumb" LG, one that transmits Geopriv LOs but does
geopriv data but does not implement or use any part of the not use any part of the Geopriv Location Object. Other cases
geopriv Location Object. Other cases may involve no IAP at may not involve any AP, or the AP may only act as a Data
all or the IAP is only a Data Transporter. Transporter.
Cuellar, Morris, Mulligan 8
Geopriv Requirements Jan 2003
3.2.3. Geopriv Data Storage Functions
Within the geopriv framework, certain data may be stored in various
functional entities:
Rule (or Policy) Storage
A storage used to store privacy-protecting policies, and
perhaps identifiers, credentials or keys. A Private Rule
Storage could be operated by a Device, a Location Server, or a
third party service provider.
How policies are authenticated and otherwise protected is outside of
the scope of this document, but see the remarks in Section 6
(Privacy Considerations).
Location Storage: Location Storage:
A Device or entity that stores raw or processed Location A Device or entity that stores raw or processed Location
Information for any period of time longer than the duration Information, such as a database, for any period of time longer
necessary to complete an immediate transaction regarding the than the duration necessary to complete an immediate
LI. transaction regarding the Location Information.
Cuellar, Morris, Mulligan, Peterson, Polk 11
Geopriv Requirements Mar 2003
The existence and data storage practices of Location Storage is The existence and data storage practices of Location Storage is
crucial to privacy considerations, because this may influence what crucial to privacy considerations, because this may influence what
Location Information could eventually be revealed (through later Location Information could eventually be revealed (through later
distribution, technical breach, or legal processes). distribution, technical breach, or legal processes).
3.3. Privacy Policies and Rules 5.5. Privacy Rules
Privacy Policies are rules that regulate an entity's activities with Privacy Rules are rules that regulate an entity's activities with
respect to location and other information, including, but not respect to location and other information, including, but not
limited to, the collection, use, disclosure, and retention of limited to, the collection, use, disclosure, and retention of
location information. Such rules are generally based on fair location information. Such rules are generally based on fair
information practices, as detailed in (for example) the OECD information practices, as detailed in (for example) the OECD
Guidelines on the Protection of Privacy and Transporter Flows of Guidelines on the Protection of Privacy and Transporter Flows of
Personal Data [OECD]. Personal Data [OECD].
Privacy Policy or Privacy Rule: Privacy Rule:
A rule or set of rules that regulate an entity's activities A rule or set of rules that regulate an entity's activities
with respect to location information, including the with respect to location information, including the
collection, use, disclosure, and retention of location collection, use, disclosure, and retention of location
information. In particular, the policy describes how location information. In particular, the Rule describes how location
information may be used by an entity and which transformed information may be used by an entity and which transformed
location information may be released to which entities under location information may be released to which entities under
which conditions. Policies must be obeyed; they are not which conditions. Rules must be obeyed; they are not
advisory. advisory.
A full set of Privacy Rules will likely include both rules that have A full set of Privacy Rules will likely include both rules that have
only one possible technical meaning, and rules that will be affected only one possible technical meaning, and rules that will be affected
by a locality's prevailing laws and customs. For example, a by a locality's prevailing laws and customs. For example, a
distribution rule of the form "my location can only be disclosed to distribution rule of the form "my location can only be disclosed to
the owner of such credentials and in such accuracy" has clear-cut the owner of such credentials and in such precision or resolution"
implications for the protocol that uses the LO. But other rules, has clear-cut implications for the protocol that uses the LO. But
other rules, like retention or usage Rules, may have unclear
Cuellar, Morris, Mulligan 9 technical consequences for the protocol or for the involved
Geopriv Requirements Jan 2003 entities. For example, the precise scope of a retention rule
stating "you may not store my location for more than 2 days" may in
like retention or usage policies, may have unclear technical part turn on local laws or customs.
consequences for the protocol or for the involved entities. For
example, the precise scope of a retention rule stating "you may not
store my location for more than 2 days" may in part turn on local
laws or customs.
3.4. Identifiers, Authentication and Authorization 5.6. Identifiers, Authentication and Authorization
Anonymity is the property of being not identifiable (within a set of Anonymity is the property of being not identifiable (within a set of
subjects). Anonymity serves as the base case for privacy: without subjects). Anonymity serves as the base case for privacy: without
the ability to remain anonymous, individuals cannot control their the ability to remain anonymous, individuals may be unable to
own privacy. Unlinkability ensures that a user may make multiple control their own privacy. Unlinkability ensures that a user may
uses of resources or services without others being able to link make multiple uses of resources or services without others being
these uses together. Unlinkability requires that entities are able to link these uses to each other. Unlinkability requires that
unable to determine whether the same user caused certain specific entities are unable to determine whether the same user caused
operations in the system. [ISO99] A pseudonym is simply a bit certain specific operations in the system. [ISO99] A pseudonym is
string which is unique as ID and is suitable to be used for end- simply a bit string which is unique as ID and is suitable to be used
point authentication. for end-point authentication.
Cuellar, Morris, Mulligan, Peterson, Polk 12
Geopriv Requirements Mar 2003
Unlinked Pseudonym: Unlinked Pseudonym:
A pseudonym where the linking between the pseudonym and its A pseudonym where the linking between the pseudonym and its
holder is, at least initially, not known to anybody with the holder is, at least initially, not known to anybody with the
possible exception of the holder himself or a trusted server possible exception of the holder himself or a trusted server
of the user. See [Pfi01] (there the term is called Initially of the user. See [Pfi01] (there the term is called Initially
Unlinked Pseudonym) Unlinked Pseudonym)
The word authentication is used in different meanings. Some require The word authentication is used in different meanings. Some require
that authentication associates an entity with a more or less well- that authentication associates an entity with a more or less well-
skipping to change at line 531 skipping to change at line 669
authentication is "explicit": authentication is "explicit":
Explicit Authentication: Explicit Authentication:
The act of verifying a claimed identity as the sole originator The act of verifying a claimed identity as the sole originator
of a message (message authentication) or as the end-point of a of a message (message authentication) or as the end-point of a
channel (entity authentication). Moreover, this identity is channel (entity authentication). Moreover, this identity is
easily linked back to the real identity of the entity in easily linked back to the real identity of the entity in
question, for instance being a pre-existing static label from question, for instance being a pre-existing static label from
a predefined name space (telephone number, name, etc.). a predefined name space (telephone number, name, etc.).
Authorization Authorization:
The act of determining if a particular right, such as access The act of determining if a particular right, such as access
to some resource, can be granted to the presenter of a to some resource, can be granted to the presenter of a
particular credential. particular credential.
Depending on the type of credential, authorization may imply Depending on the type of credential, authorization may imply
Explicit Authentication or not. Explicit Authentication or not.
Cuellar, Morris, Mulligan 10 6. Scenarios and Explanatory Discussion
Geopriv Requirements Jan 2003
4. Scenarios and Explanatory Discussion
4.1. Scenarios of Data Flow
In this subsection we introduce short scenarios to illustrate how In this subsection we introduce short scenarios to illustrate how
these terms and attributes describe location information these terms and attributes describe location information
transactions. transactions. Additional illustrative scenarios are discussed in a
separate Document.
SCENARIO 1: GPS Device with Internal Computing Power: Closed System SCENARIO 1: GPS Device with Internal Computing Power: Closed System
In this example, the Target wishes to know his/her location using In this example, the Target wishes to know his/her location using
Global Positioning System (GPS) and the Device is capable of Global Positioning System (GPS) and the Device is capable of
independently processing the raw data to determine its location. independently processing the raw data to determine its location.
The location is derived as follows: the Device receives The location is derived as follows: the Device receives
transmissions from the GPS satellites, internally computes and transmissions from the GPS satellites, internally computes and
displays location. This is a closed system. For the purpose of this displays location. This is a closed system. For the purpose of this
and subsequent examples, it is assumed that the GPS satellite and subsequent examples, it is assumed that the GPS satellite
broadcasts some signal, and has no information about the identity or broadcasts some signal, and has no information about the identity or
whereabouts of Devices using the signal. whereabouts of Devices using the signal.
Cuellar, Morris, Mulligan, Peterson, Polk 13
Geopriv Requirements Mar 2003
GPS Satellite GPS Satellite
| |
| Sighting (not a Geopriv Interface)
| |
| |
| |
V GPS Device V GPS Device
-------------------------------------------------- --------------------------------------------------
/ \ / \
| Data ----- Location ----- Location | | Location ----- Location ----- Location |
| Transporter Server Storage | | Generator Server Storage |
\ | / \ | /
-------------------------------------------|------ -------------------------------------------|------
| |
| Notification
| Interface
|
------------|------ ------------|------
/ V \ / V \
/ Target Location \ / Target Location \
| Seeker | | Recipient |
| | | |
\ Rule Maker / \ Rule Maker /
\ / \ /
------------------- -------------------
In this scenario the GPS Device is both the IAP and the LoSi. The In this scenario the GPS Device is both the AP and the LG. The
interaction occurs in a Trusted environment because it occurs in the interaction occurs in a Trusted environment because it occurs in the
Rule MakerĘs Device. Rule MakerĘs Device.
SCENARIO 2: Cell Phone Roaming SCENARIO 2: Cell Phone Roaming
In this example, a cell phone is used outside its home service area In this example, a cell phone is used outside its home service area
(roaming). Also, the cell phone service provider (cell phone Corp 2) (roaming). Also, the cell phone service provider (cell phone Corp 2)
Cuellar, Morris, Mulligan 11
Geopriv Requirements Jan 2003
outsourced the accounting of cell phone usage. The cell phone is not outsourced the accounting of cell phone usage. The cell phone is not
GPS-enabled. Location is derived by the cell phone network in which GPS-enabled. Location is derived by the cell phone network in which
the Target and Device are roaming. When the Target wishes to use the Target and Device are roaming. When the Target wishes to use
the cell phone, cell phone Corp 1 (IAP) provides the roaming service the cell phone, cell phone Corp 1 (AP) provides the roaming service
for the Target, which sends the raw data about usage (e.g., duration for the Target, which sends the raw data about usage (e.g., duration
of call, location ” roaming network, etc.) to cell phone Corp 2, the of call, location ” roaming network, etc.) to cell phone Corp 2, the
home service provider. Cell phone Corp 2 submits the raw data to home service provider. Cell phone Corp 2 submits the raw data to
the accounting company, which processes the raw data for the the accounting company, which processes the raw data for the
accounting statements. Finally, the raw data is sent to a data accounting statements. Finally, the raw data is sent to a data
warehouse where the raw data is stored in a Location Server (e.g., warehouse where the raw data is stored in a Location Server (e.g.,
computer server). computer server).
Cuellar, Morris, Mulligan, Peterson, Polk 14
Geopriv Requirements Mar 2003
Cell Phone Corp 1 Cell Phone Corp 2 Cell Phone Corp 1 Cell Phone Corp 2
----------------- ----------------- ----------------- -----------------
Sighting / \ Sighting / \ Sighting / \ Publish / \
Device ----- | Data Transporter | --------- | Data Transporter | Device ----- | Data Transporter | --------- | Data Transporter |
Target \ / \ / Target \ / Interface \ /
----------------- / ----------------- ----------------- / -----------------
/ | / |
/ sighting| / | Notification
/ | / | Interface
----------- | ----------- |
/ V / V
------------ / ---------- ------------ / ----------
/ \ / / \ / \ / / \
/ Location \ / | Location | / Location \ / | Location |
| Storage | Location Info | Storage | | Storage | Location Info | Storage |
| |<----------------- | | | |<----------------- | |
| Location | | Location | | Location | | Location |
| Seeker | | Seeker | | Recipient | | Recipient |
\ / \ / \ / \ /
------------- ---------- ------------- ----------
Here cell phone corp 1 is the IAP and the LoSi. Cell phone corp 1 Here cell phone Corp 1 is the AP and the LG. In this scenario, Cell
could be Non-trusted (the Rule Maker does not have a contract phone Corp 2 is likely to be a Trusted entity, but cell phone Corp
protecting location information with corp 1 and there is no 1 may be Non-trusted.
contractual relationship with privacy provisions between corp 1 and
corp 2) or Trusted (contract with privacy protections between cell
phone corp 2 and corp 1). Cell phone corp 2 is Trusted.
SCENARIO 3: Mobile Communities and Location-Based Services SCENARIO 3: Mobile Communities and Location-Based Services
The figure below shows a common scenario, where a user wants to find The figure below shows a common scenario, where a user wants to find
his friends or colleagues or wants to share his position with them his friends or colleagues or wants to share his position with them
or with a Location-Based Service Provider. Some of the messages use or with a Location-Based Service Provider. Some of the messages use
a Location Object to carry for instance: identities or pseudonyms, a Location Object to carry, for instance, identities or pseudonyms,
credentials and proof-of-possession of them, Policies and Location credentials and proof-of-possession of them, Rules and Location Data
Data Information, including Data Types and Accuracy. They are shown Information, including Data Types and Precision or Resolution.
in the figure by normal arrows ("--->"). Other messages do not use Messages that do not use the Location Object and are outside of the
scope of the Geopriv WG, but should be mentioned for
Cuellar, Morris, Mulligan 12 understandability, are shown in the figure as starred arrows
Geopriv Requirements Jan 2003 ("***>").
the Location Object and are outside of the scope of the geopriv WG, Cuellar, Morris, Mulligan, Peterson, Polk 15
but should be mentioned for understandability. They are shown in Geopriv Requirements Mar 2003
the figure as starred arrows ("***>").
+---------+ +------------+ +---------+ +------------+
| Location| | Public | | | | |
| Data |<** | Policy | | Location|<** | Public |
| Source | * | Repository | |Generator| * | Rule Holder|
| + IAP | * +------------+ | | * | |
+---------+\ * * * +---------+\ * +------------+
^ \ *5 3a* * \ *3 1a* *
* \ * * * \ * * *
* \ ** * \ ** *
* \ * * *3a \ * * *1a
5a * \* * * \* * *
* * \ * * * \ * *
* * \ * * * \ * *
* * \6 * * * \4 * *
+----------+ * \ * V * \ * V
| Target | * \->+-----------+ * \->+-----------+
| +----------+ 3 | Location | +----------+ 1 | Location |
+-| Rule |--------------------->| Server + | | Rule |--------------------->| Server + |
| Maker | | Private | | Maker | | Private |
+----------+<********************>| Repository| +----------+ |Rule Holder|
^ 1 +-----------+ +-----------+
| ^ | ^ |
| 4| |7 3| |5
| | V | V
| +----------+ +----------+
| | Ultimate | | Location |
+---------------------------->| Location | | Recipient|
2 | Recipient|
+----------+ +----------+
Figure 1: The Entities and Data Flows Assume that the Rule Maker and the Target are registered with the
Location Server. The RM has somehow proven to the LS that he indeed
1: Registration: is the owner of the privacy rights of the Target (the Target is
The Rule Maker registers himself and the Target with the usually a Device owned by the Rule Maker). The Rule Maker and the
Location Server. This registration process is outside of the Location Server have agreed on the set of keys or credentials and
scope of our discussion, but probably the Rule Maker has to cryptographic material that they will use to authenticate each
prove that he indeed is the owner of the privacy rights of the other, and in particular, to authenticate or sign the Rules. How
Target (the Target is usually a Device owned by the Rule this has been done is outside of the scope of the document.
Maker). The Rule Maker and the Location Server agree, as part
of the Registration Process, which keys or credentials and
proof-of-possession of the corresponding secrets they will use
to authenticate each other, and in particular, to authenticate
or sign the policies, or how they will agree on them or renew
those keys or credentials.
Cuellar, Morris, Mulligan 13 1: Rule Transfer:
Geopriv Requirements Jan 2003 The Rule Maker sends a Rule to the Location Server. This Rule
may be a field in a Location Object or not.
2: End-to-End Negotiation: 1a:Signed Rule:
The Rule Maker and the Location Seeker exchange information As an alternative, the Rule Maker may write a Rule and place
about the service (if any) and negotiate it. They also it in a Public Rule Holder. The entities access the
negotiate the pseudonyms that they will use later on and the repository to read the signed Rules.
credentials or keys that the Ultimate Location Recipient will
use to prove his authorization to the Location Server. This
End-to-End Negotiation may contain several messages and may
use or not the Location Object.
3: Policy Transfer: 2: Location Information Request:
The Rule Maker sends a Policy to the Location Server. This The Location Recipient requests location information for a
Policy may be a field in a Location Object or not.
3a:Signed Policy: Cuellar, Morris, Mulligan, Peterson, Polk 16
As an alternative to the Policy Transfer, the Rule Maker may Geopriv Requirements Mar 2003
write a policy and place it in the Open Repository. The
entities access the repository to read the signed policies.
4: Location Information Request: Target. In this request, the Location Recipient may select
The Location Seeker requests location information for a which location information data type it prefers. One way of
Target. In this request, the Location Seeker may select which
location information data type it prefers. One way of
requesting Location Information MAY be sending a partially requesting Location Information MAY be sending a partially
filled Location Object, including only the identities of the filled Location Object, including only the identities of the
Target and Location Recipient and the desired Data Type and Target and Location Recipient and the desired Data Type and
accuracy, and providing proof of possession of the required precision or resolution, and providing proof of possession of
credentials. But whether the using protocol understands this the required credentials. But whether the using protocol
partially filled object as a request, this MAY depend on the understands this partially filled object as a request, this
using protocol or on the context. The Location Seeker could MAY depend on the using protocol or on the context. The
also specify the need for periodic location information Location Recipient could also specify the need for periodic
updates, but this is probably out of the scope of geopriv. location information updates, but this is probably out of the
scope of Geopriv.
5: Locate: 3: Locate:
When a Location Server receives an Location Information When a Location Server receives an Location Information
Request for a Target for which has no current location Request for a Target for which has no current location
information, the server may send ask the Location Sighter to information, the server may send ask the Location Generator to
locate the Target. locate the Target.
6: Location Information: 4: Location Information:
The Location Sighter sends the "full" location information to The Location Generator sends the "full" location information
the Location Server. This Location Information may be to the Location Server. This Location Information may be
embedded in a Location Object or not. embedded in a Location Object or not.
7: Filtered Location Information: 5: Filtered Location Information:
Then the Location Server sends the location information to the Then the Location Server sends the location information to the
Location Recipient. The information may be filtered in the Location Recipient. The information may be filtered in the
sense that in general a less precise or a computed version of sense that in general a less precise or a computed version of
the information is being delivered. the information is being delivered.
5. Requirements 7. Requirements
Cuellar, Morris, Mulligan 14 7.1. Location Object
Geopriv Requirements Jan 2003
5.1. Location Object Recall that this document is primarily specifying requirements on
how the definition of the LO. Some Requirements read like this:
"The LO definition MUST contain Field 'A' as an optional field."
This requirement just states that
o the document that defines the LO MUST define the LO field 'A',
o the field 'A' MUST be defined as optional to use (an instance of a
LO MAY contain the field 'A' or not).
Some Requirements read like this: "The LO definition MUST contain
Field 'A', which MAY be an optional field." This requirement states
that
o the document that defines the LO MUST define the LO field 'A',
o the field 'A' MAY be defined as optional or not to use. If it is
defined as optional to use, any instance of a LO MAY contain the
field 'A' or not; if it is not optional, all instances of LOs MUST
contain the field 'A'.
Cuellar, Morris, Mulligan, Peterson, Polk 17
Geopriv Requirements Mar 2003
Req. 1. (Location Object generalities) Req. 1. (Location Object generalities)
1.1) Geopriv MUST define one Location Object (LO) -- both in 1.1) Geopriv MUST define one Location Object (LO) -- both in
syntax and semantics -- that must be supported by all geopriv syntax and semantics -- that must be supported by all Geopriv
entities. entities.
1.2) Some fields of the Location Object MAY be optional. This 1.2) Some fields of the Location Object MAY be optional. This
means that an instance of a Location Object MAY contain the means that an instance of a Location Object MAY contain the
fields or not. fields or not.
1.3) Some fields of the Location Object MAY be defined as 1.3) Some fields of the Location Object MAY be defined as
"extensions". This means that the syntax or semantics of these "extensions". This means that the syntax or semantics of these
fields is not fully defined in the basic Location Object fields is not fully defined in the basic Location Object
definition, but their use may be private to one or more using definition, but their use may be private to one or more using
protocols. protocols.
1.4) The Location Object MUST be extensible, allowing the 1.4) The Location Object MUST be extensible, allowing the
definition of new attributes or fields. definition of new attributes or fields.
1.5) The object MUST be suitable for requesting and receiving a 1.5) The object MUST be suitable for requesting and receiving a
location. location.
1.6) The object MUST permit (but not require) the policy to be 1.6) The object MUST permit (but not require) the Privacy Rules
enforced by a third party. to be enforced by a third party.
1.7) The object MUST be usable in a variety of protocols, such as 1.7) The object MUST be usable in a variety of protocols, such as
HTTP and SIP, as well as local APIs. HTTP and SIP, as well as local APIs.
1.8) The object MUST be usable in a secure manner even by 1.8) The object MUST be usable in a secure manner even by
applications on constrained devices. applications on constrained devices.
Req. 2. (Location Object fields) The Location Object definition Req. 2. (Location Object fields) The Location Object definition
MUST support the following Fields (but not all LOs must use all MUST contain the following Fields, which MAY be optional to use:
fields)
2.1) Target Identifier 2.1) Target Identifier
2.2) Location Recipient Identity 2.2) Location Recipient Identity
This identity may be a multicast or group identity, used to This identity may be a multicast or group identity, used to
include the Location Object in multicast-based using protocols. include the Location Object in multicast-based using protocols.
2.3) Location Recipient Credential 2.3) Location Recipient Credential
2.4) Location Recipient Proof-of-Possession of the Credential 2.4) Location Recipient Proof-of-Possession of the Credential
2.5) Location Field. 2.5) Location Field.
Cuellar, Morris, Mulligan 15 2.5.1) Motion and direction vectors. This field MUST be
Geopriv Requirements Jan 2003 optional.
Each Location Field may contain one or more Location Cuellar, Morris, Mulligan, Peterson, Polk 18
Representations, which can be also in different formats. Geopriv Requirements Mar 2003
2.6) Location Data Type 2.6) Location Data Type
When transmitting the Location Object, the sender and the When transmitting the Location Object, the sender and the
receiver must agree on the data type of the location information. receiver must agree on the data type of the location information.
The using protocol may specify that the data type information is The using protocol may specify that the data type information is
part of the Location Object or that sender and receiver have part of the Location Object or that sender and receiver have
agreed on it before the actual data transfer. agreed on it before the actual data transfer.
2.7) Motion and direction vectors 2.7) Timing information:
(a) When was the Location Information accurate? (sighting time)
2.8) Timing information:
(a) When was the LI accurate? (sighting time)
(b) Until when considered current? TTL (Time-to-live) (This is (b) Until when considered current? TTL (Time-to-live) (This is
different than a privacy rule setting a limit on data retention) different than a privacy rule setting a limit on data retention)
2.9) Policy Field: this field MAY be a referral to an applicable 2.8) Rule Field: this field MAY be a referral to an applicable
policy (for instance, an URI to a full policy), or it MAY contain Rule (for instance, an URI to a full Rule), or it MAY contain a
a Limited Policy (see Req. 9), or both. Limited Rule (see Req. 11), or both.
2.10) Security-headers and -trailers (for instance encryption 2.9) Security-headers and -trailers (for instance encryption
information, hashes, or signatures) (see Req. 13). information, hashes, or signatures) (see Req. 14 and 15).
2.11) Version number 2.10) Version number
Req. 3. (Location Data Types) Req. 3. (Location Data Types)
3.1) The Location Object MUST define at least one Location Data 3.1) The Location Object MUST define at least one Location Data
Type to be supported by all geopriv receivers (entities that Type to be supported by all Geopriv receivers (entities that
receive LOs). receive LOs).
3.2) The Location Object SHOULD define two Location Data Types: 3.2) The Location Object SHOULD define two Location Data Types:
one for latitude / longitude / altitude coordinates and one for one for latitude / longitude / altitude coordinates and one for
civil locations (City, Street, Number) supported by all geopriv civil locations (City, Street, Number) supported by all Geopriv
receivers (entities that receive LOs). receivers (entities that receive LOs).
3.3) The latitude / longitude / altitude Data Type SHOULD also 3.3) The latitude / longitude / altitude Data Type SHOULD also
support a delta format in addition to an absolute one, used for support a delta format in addition to an absolute one, used for
the purpose of reducing the size of the packages or the security the purpose of reducing the size of the packages or the security
and confidentiality needs. and confidentiality needs.
3.4) The Location Object definition SHOULD agree on further 3.4) The Location Object definition SHOULD agree on further
Location Data Types supported by some geopriv entities and Location Data Types supported by some Geopriv entities and
defined by other organizations. defined by other organizations.
5.2. The Using Protocol 7.2. The Using Protocol
Req. 4. The using protocol has to obey the privacy and security Req. 4. The using protocol has to obey the privacy and security
instructions coded in the Location Object and in the instructions coded in the Location Object and in the
corresponding Rules regarding the transmission and storage of the
Cuellar, Morris, Mulligan 16 LO.
Geopriv Requirements Jan 2003
corresponding Policy Rules regarding the transmission and storage
of the LO.
Req. 5. The using protocol will typically facilitate that the keys Req. 5. The using protocol will typically facilitate that the keys
associated with the credentials are transported to the respective associated with the credentials are transported to the respective
Cuellar, Morris, Mulligan, Peterson, Polk 19
Geopriv Requirements Mar 2003
parties, that is, key agreement is responsibility of the using parties, that is, key agreement is responsibility of the using
protocol. protocol.
Req. 6. (Single Message Transfer) In particular for tracking of Req. 6. (Single Message Transfer) In particular for tracking of
small target devices, the design should allow a single small target devices, the design should allow a single
message/packet transmission of location as a complete message/packet transmission of location as a complete
transaction. transaction.
Other requirements on the using protocol are out of the scope of Other requirements on the using protocol are out of the scope of
this document. See also Section 9 (Protocol and LO Issues for later this document, but might be the subject of future efforts from this
working group. See also Section 9 (Protocol and LO Issues for later
Consideration) Consideration)
5.3. Policy based Location Data Transfer 7.3. Rule based Location Data Transfer
Req. 7. (LServ Policies) The decision of a Location Server to Req. 7. (LS Rules) The decision of a Location Server to provide a
provide a Location Seeker access to Location Information MUST be Location Recipient access to Location Information MUST be based
based on Rule Maker-defined Privacy Policies. on Rule Maker-defined Privacy Rules.
It is outside of our scope how Privacy Policies are managed, how a It is outside of our scope how Privacy Rules are managed and how a
Location Server has access to the Privacy Policies, and if he is or Location Server has access to the Privacy Rules. Note that it might
not aware of the full set of rules desired by the Rule-Maker. Note be that some rules contain private information not intended for
that it might be that some rules contain private information not untrusted parties.
intended for untrusted parties.
Req. 8. (LoSi Policies) Even if a Location Sighter is unaware of Req. 8. (LG Rules) Even if a Location Generator is unaware of and
and lacks access to the full Privacy Policies defined by the Rule lacks access to the full Privacy Rules defined by the Rule Maker,
Maker, the Location Sighter MUST transmit Location Information in the Location Generator MUST transmit Location Information in
compliance with instructions set by the Rule Maker. Such compliance with instructions set by the Rule Maker. Such
compliance MAY be accomplished by the Location Sighter compliance MAY be accomplished by the Location Generator
transmitting LI only to a URI designated by the Rule Maker. transmitting the LO only to a URI designated by the Rule Maker.
Req. 9. (ULR Policies) An Ultimate Location Recipient does not need
to be aware of the full policies defined by the Rule Maker
(because an ULR SHOULD NOT retransmit Location Information), and
thus an ULR SHOULD receive only the subset of Privacy Policies
necessary for the ULR to handle the LI in compliance with the
full Privacy Policies (such as, for example, an instruction on
the time period for which then LI can be retained).
Req. 10. (Full Policy language) Geopriv MAY specify a policy Req. 9. (Viewer Rules) An Viewer does not need to be aware of the
language capable of expressing a wide range of privacy rules full Rules defined by the Rule Maker (because an Viewer SHOULD
concerning location information. This policy language MAY be an NOT retransmit Location Information), and thus an Viewer SHOULD
existing one, an adaptation of an existing one or a new policy receive only the subset of Privacy Rules necessary for the Viewer
language, and it SHOULD be as simple as possible. to handle the LO in compliance with the full Privacy Rules (such
as, for example, an instruction on the time period for which then
the LO can be retained).
Req. 11. (Limited Policy language) Geopriv MUST specify a limited Req. 10. (Full Rule language) Geopriv MAY specify a Rule language
policy language capable of expressing a limited set of privacy capable of expressing a wide range of privacy rules concerning
location information. This Rule language MAY be an existing one,
an adaptation of an existing one or a new Rule language, and it
SHOULD be as simple as possible.
Cuellar, Morris, Mulligan 17 Req. 11. (Limited Rule language) Geopriv MUST specify a limited
Geopriv Requirements Jan 2003 Rule language capable of expressing a limited set of privacy
rules concerning location information. This Rule language MAY be
an existing one, an adaptation of an existing one or a new Rule
language. The Location Object MUST include sufficient fields and
data to express the limited set of privacy rules.
rules concerning location information. This policy language MAY Cuellar, Morris, Mulligan, Peterson, Polk 20
be an existing one, an adaptation of an existing one or a new Geopriv Requirements Mar 2003
policy language. The Location Object MUST include sufficient
fields and data to express the limited set of privacy rules.
5.4. Location Object Privacy and Security 7.4. Location Object Privacy and Security
5.5. Identity Protection 7.4.1. Identity Protection
Req. 12. (Identity Protection) The Location Object MUST support use Req. 12. (Identity Protection) The Location Object MUST support use
of Unlinked Pseudonyms in the corresponding identification fields of Unlinked Pseudonyms in the corresponding identification fields
of Rule Maker, Target, Device, and Location Recipient. Since of Rule Maker, Target, Device, and Location Recipient. Since
Unlinked Pseudonyms are simply bit strings that are not linked Unlinked Pseudonyms are simply bit strings that are not linked
initially to a well-known identity, this requirement boils down initially to a well-known identity, this requirement boils down
to saying that the name space for Identifiers used in the LO has to saying that the name space for Identifiers used in the LO has
to be large enough to contain many unused strings. to be large enough to contain many unused strings.
5.6. Authentication Requirements 7.4.2. Authentication Requirements
Req. 13. (Credential Requirements) The using protocol and the Req. 13. (Credential Requirements) The using protocol and the
Location Object SHOULD allow the use of different credentials Location Object SHOULD allow the use of different credentials
types, including privacy-enhancing credentials (like for instance types, including privacy-enhancing credentials (like for instance
the ones described in [Bra00] or [Cha85]). the ones described in [Bra00] or [Cha85]).
5.7. Actions to be secured 7.4.3. Actions to be secured
Req. 14. (Security Features) The Location Object MUST support Req. 14. (Security Features) The Location Object MUST support
fields suitable for protecting the Object to provide the fields suitable for protecting the Object to provide the
following security features: following security features:
14.1) Mutual end-point authentication: the using protocol is 14.1) Mutual end-point authentication: the using protocol is
able to authenticate both parties in a Location Object able to authenticate both parties in a Location Object
transmission, transmission,
14.2) Data object integrity: the LO is secured from 14.2) Data object integrity: the LO is secured from
skipping to change at line 970 skipping to change at line 1107
14.4) Replay protection: an old LO may not be replayed by an 14.4) Replay protection: an old LO may not be replayed by an
adversary or by the same entity that used the LO itself (except adversary or by the same entity that used the LO itself (except
perhaps during a small window of time that is configurable or perhaps during a small window of time that is configurable or
accepted by the Rule Maker). accepted by the Rule Maker).
Req. 15. (Minimal Crypto) Req. 15. (Minimal Crypto)
15.1) Geopriv MUST specify a minimum mandatory to implement 15.1) Geopriv MUST specify a minimum mandatory to implement
Location Object security including mandatory to implement crypto Location Object security including mandatory to implement crypto
Cuellar, Morris, Mulligan 18
Geopriv Requirements Jan 2003
algorithms, for digital signature algorithms and encryption algorithms, for digital signature algorithms and encryption
algorithms. algorithms.
15.2) It MAY also define further mandatory to implement 15.2) It MAY also define further mandatory to implement
Location Object security mechanisms for message authentication Location Object security mechanisms for message authentication
codes (MACs) or other purposes. codes (MACs) or other purposes.
Cuellar, Morris, Mulligan, Peterson, Polk 21
Geopriv Requirements Mar 2003
15.3) The protocol SHOULD allow a bypass if authentication 15.3) The protocol SHOULD allow a bypass if authentication
fails in an emergency call. fails in an emergency call.
The issue addressed in the last point is that an emergency call in The issue addressed in the last point is that an emergency call in
some very unfavorable situations my not be completed if the minimal some unfavorable situations may not be completed if the minimal
authentication fails. This is probably not what the user would like authentication fails. This is probably not what the user would like
to see. The user may prefer an unauthenticated call to an to happen. The user may prefer an unauthenticated call to an
unauthenticated emergency server than no call completion at all, unauthenticated emergency server over no call completion at all,
even at the risk that he is talking to an attacker or that his even at the risk that he is talking to an attacker or that his
information is not secured. information is not secured.
5.8. Non-Requirements 7.5. Non-Requirements
Non-Req. 1. (Bridging to non-IP networks) The geopriv specification Non-Req. 1. (Bridging to non-IP networks) The Geopriv specification
SHOULD NOT specify the bridging to non-IP networks (PSTN, etc). SHOULD NOT specify the bridging to non-IP networks (PSTN, etc).
6. Security Considerations 8. Security Considerations
The purpose of the geopriv Location Object and the requirements on The purpose of the Geopriv Location Object and the requirements on
the using protocol are to allow a policy-controlled disclosure of the using protocol are to allow a Privacy Rule-controlled disclosure
location information for location services. of location information for location services.
6.1. Traffic Analysis 8.1. Traffic Analysis
The information carried within the Location Object is secured in a The information carried within the Location Object is secured in a
way compliant with the privacy and security policies of the Rule way compliant with the privacy and security Rules of the Rule Maker,
Maker, but other information, carried in other objects or headers but other information, carried in other objects or headers are in
are in general not secured in the same way. This means that geopriv general not secured in the same way. This means that Geopriv may
does not as a general matter secure the Target against general not as a general matter secure the Target against general traffic
traffic analysis attacks or other forms of privacy violations. analysis attacks or other forms of privacy violations.
6.2. Securing the Privacy Policies
The Privacy Policies of the Rule Maker regarding the location of the 8.2. Securing the Privacy Rules
Target may be accessible to a Location Server in a Private Storage
or in a Public Repository, or they may be carried by the Location
Object, or they may be presented by the Location Seeker as
capabilities or tokens. Each of this types of policy has to be
secured itĘs own particular way.
The rules in a Private Storage are typically authenticated using a The Privacy Rules of the Rule Maker regarding the location of the
MAC (Message Authentication Code) or a signature, depending on the Target may be accessible to a Location Server in a public or non-
type of keys used. The rules in a Public Repository (one that in public Rule Holder, or they may be carried by the Location Object,
or they may be presented by the Location Recipient as capabilities
or tokens. Each of this types of Rule has to be secured it's own
particular way.
Cuellar, Morris, Mulligan 19 The rules in a non-public Rule Holder are typically authenticated
Geopriv Requirements Jan 2003 using a MAC (Message Authentication Code) or a signature, depending
on the type of keys used. The rules in a public Rule Holder (one
that in principle may be accessed directly by several entities, for
instance several Location Servers) are typically digitally signed.
Rule Fields in a LO are secured as part of the LO itself. A Geopriv
Token (a token or ticket issued by the Rule Maker to a Location
Recipient, expressing the explicit consent of the Rule Maker to
access his location information) is authenticated or signed.
principle may be accessed directly by several entities, for instance Cuellar, Morris, Mulligan, Peterson, Polk 22
several Location Servers) are typically digitally signed. A Policy Geopriv Requirements Mar 2003
Field in a LO is secured as part of the LO itself. A Geopriv Token
(a token or ticket issued by the Rule Maker to a Location Seeker,
expressing the explicit consent of the Rule Maker to access his
location information) is authenticated or signed.
6.3. Emergency Case 8.3. Emergency Case
One way of implementing the authentication bypass for emergency Let us consider the situation where the authentication fails in an
calls, mentioned in Req 14.3) is to let the user have the choice of emergency call because the authentication center fails to
writing a policy that says: authenticate itself. In this case, one way of implementing the
- "If the emergency server does not authenticate itself, authentication bypass for emergency calls, mentioned in Req 15.3) is
nevertheless send the location", or to let the user have the choice of writing a Rule that says:
- "If the emergency server does not authenticate itself, send the
location information anyway", or
- "If the emergency server does not authenticate itself, let the - "If the emergency server does not authenticate itself, let the
call fail". call fail".
In the case where the authentication of the emergency call fails Second, in the case where the authentication of the emergency call
because the user may not authenticate itself, the question arises: fails because the user may not authenticate itself, the question
whose policy to use? It is reasonable to use a default one: this arises: whose Rule to use? It is reasonable to use a default one:
location information can only be sent to an emergency center. this location information can only be sent to an emergency center.
Another situation, which should be studied in more detail is: what The third situation, which should be studied in more detail, is:
to do if not only the user fails to authenticate itself, but also what to do if not only the user fails to authenticate itself, but
the emergency center is not authenticable? It is reasonable to send also the emergency center is not authenticable? It is reasonable to
the Location Information anyway, but are there in this case any send the Location Information anyway, but are there in this case any
security threats that must be considered? security threats that must be considered?
6.4. Identities and Anonymity 8.4. Identities and Anonymity
The use of Unlinked Pseudonyms is necessary to obtain anonymity. The use of Unlinked Pseudonyms is necessary to obtain anonymity.
The purpose of the use of Unlinked Pseudonyms is the following: the The purpose of the use of Unlinked Pseudonyms is the following: the
using protocol should be able to hide the real identity of the Rule using protocol should be able to hide the real identity of the Rule
Maker, the Target, and the Device, the and to Location Servers or Maker, the Target, and the Device, to Location Servers or Location
Location Recipients. Also, the using protocol SHOULD be able to Recipients, if required by the RM. Also, the using protocol SHOULD
hide the real identity of the Location Recipient to the Location be able to hide the real identity of the Location Recipient to the
Server. Location Server.
In this last case, the Target is not concerned about the Server In this last case, the Target is not concerned about the Server
identifying him and knowing his location, but identifying his identifying him and knowing his location, but identifying his
business partners, and therefore his habits, etc. Reasons for business partners, and therefore his habits, etc. Reasons for
hiding the real identities of the Location Recipients include (a) hiding the real identities of the Location Recipients include (a)
that this knowledge may be used to infer the identity of the Target, that this knowledge may be used to infer the identity of the Target,
(b) that knowledge of the identity of the Location Recipient may (b) that knowledge of the identity of the Location Recipient may
embarrass the Target or breach confidential information, and (c) embarrass the Target or breach confidential information, and (c)
that the dossier telling who has obtained a Target's location that the dossier telling who has obtained a Target's location
information over a long period of time can give information on information over a long period of time can give information on
habits, movements, etc. Even if the location service providers habits, movements, etc. Even if the location service providers
agree to respect the privacy of the user, are compelled by laws or agree to respect the privacy of the user, are compelled by laws or
regulations to protect the privacy of the user, and misbehavior or regulations to protect the privacy of the user, and misbehavior or
Cuellar, Morris, Mulligan 20
Geopriv Requirements Jan 2003
negligence of the Location Server can be ruled out, there is still negligence of the Location Server can be ruled out, there is still
risk that personal data may become available to unauthorized persons risk that personal data may become available to unauthorized persons
through attacks from outsiders, unauthorized access from insiders, through attacks from outsiders, unauthorized access from insiders,
technical or human errors, or legal processes. technical or human errors, or legal processes.
In some occasions a Location Server has to know who is supplying Cuellar, Morris, Mulligan, Peterson, Polk 23
policies for a particular Target, but in other situations it could Geopriv Requirements Mar 2003
be enough to know that the supplier of the policies is authorized to
do so. Those considerations are outside of our scope.
6.5. Unintended Target In some occasions a Location Server has to know who is supplying the
Privacy Rules for a particular Target, but in other situations it
could be enough to know that the supplier of the Rules is authorized
to do so.
8.5. Unintended Target
An Unintended Target is a person or object tracked by proximity to An Unintended Target is a person or object tracked by proximity to
the Target. This special case most frequently occurs if the Target the Target. This special case most frequently occurs if the Target
is not a person. For example, the Target may be a rental car is not a person. For example, the Target may be a rental car
equipped with a GPS Device, used to track car inventory. The rental equipped with a GPS Device, used to track car inventory. The rental
company may not care about the driver's location, but the driver's company may not care about the driver's location, but the driver's
privacy is implicitly affected. privacy is implicitly affected.
Geopriv may or may not protect or affect the privacy of Unintended Geopriv may or may not protect or affect the privacy of Unintended
Targets, but the impact on Unintended Targets should be Targets, but the impact on Unintended Targets should be
acknowledged. acknowledged.
7. Acknowledgements
We wish to thank the members of the IETF geopriv WG for their
comments and suggestions. Aaron Burstein, Mehmet Ersue, Allison
Mankin, Randall Gellens, Jon Peterson, and the participants of the
geopriv meetings in San Diego and Yokohama provided detailed
comments or text.
8. References
[Bra00] Stefan A.: Rethinking Public Key Infrastructures and Digital
Certificates : Building in Privacy, MIT Press; ISBN:
0262024918; 1st edition, August, 2000
[Cha85] Chaum, David: Security without Identification, Card
Computers to make Big Brother Obsolete. Original Verion
appeared in: Communications of the ACM, vol. 28 no. 10,
October 1985 pp. 1030-1044. Revised version available at
http://www.chaum.com/articles/
[ISO99] ISO99: ISO IS 15408, 1999, http://www.commoncriteria.org/.
[OECD] OECD Guidelines on the Protection of Privacy and Transborder
Flows of Personal Data, http://www.oecd.org.
[Pfi01] Pfitzmann, Andreas; K÷hntopp, Marit: Anonymity,
Unobservability, and Pseudonymity - A Proposal for
Terminology; in: H Federrath (Ed.): Designing Privacy
Cuellar, Morris, Mulligan 21
Geopriv Requirements Jan 2003
Enhancing Technologies; Proc. Workshop on Design Issues in
Anonymity and Unobservability; LNCS 2009; 2001; 1-9. Newer
versions available at http://www.koehntopp.de/marit/pub/anon
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
9. Protocol and LO Issues for later Consideration 9. Protocol and LO Issues for later Consideration
It seems important to mention some issues on the Location Object or This section briefly discusses issues relating to the Location
on the protocol, which have emerged during the discussion of earlier Object or the protocol that have emerged during the discussion of
versions of this document. earlier versions of this document.
9.1. Multiple Locations in one LO 9.1. Multiple Locations in one LO
The possibility of inclusion of multiple locations is discussed in A location Field is intended to represent one point or one region in
another draft, draft-morris-geopriv-location-object-issues-00.txt. space (either 1, 2, or 3 dimensionally). The possibility of
inclusion of multiple locations is discussed in another document.
An instance of a Location Object could contain zero, one, or several The current rough consensus is the following: the LO definition MAY
Location Fields, perhaps in different formats. Several Location allow the Location Field to be optional, to appear exactly one time
or to occur several times. Each Location Field may contain one or
more "Location Representations", each of which is intended to
represent a different measurement or a different formatting of the
same position. But there are other possibilities for using multiple
Location Fields and multiple representations: maybe several Location
Fields would be used to report the same sighting in different Fields would be used to report the same sighting in different
formats, or multiple sightings at different times, or multiple formats, or multiple sightings at different times, or multiple
sensor locations for the same device, or other purposes. sensor locations for the same device, or other purposes, which could
also depend on the using protocol. This all is for further
discussion.
9.2. Translation Fields 9.2. Translation Fields
It is possible to include fields to indicate that one of the It is possible to include fields to indicate that one of the
locations is a translation of another. If this is done, it is also locations is a translation of another. If this is done, it is also
possible to have a field to identify the translator, as identity and possible to have a field to identify the translator, as identity and
method. method.
9.3. Specifying Desired Accuracy in a Request Cuellar, Morris, Mulligan, Peterson, Polk 24
Geopriv Requirements Mar 2003
If the LO is used to request location information (leaving some
fields empty), it is not clear how to specify the requested
accuracy. Are the data types "country/state/city" and
"country/state" different data types or the same data type with
different "accuracy" or "granularity"?
9.4. Truth Flag 9.3. Truth Flag
Geopriv should not provide an attribute in object saying "I'm not Geopriv MUST be silent on the truth or lack-of-truth of the location
telling you the whole truth." information contained in the LO. Thus, the LO MUST not provide an
attribute in object saying "I am (or am not) telling you the whole
truth."
9.5. Timing Information Format 9.4. Timing Information Format
The format of timing information is out of the scope of this The format of timing information is out of the scope of this
document. document.
9.6. The Name Space of Identifiers 9.5. The Name Space of Identifiers
Cuellar, Morris, Mulligan 22
Geopriv Requirements Jan 2003
Who defines the Identities: may the using protocol define the Who defines the Identities: may the using protocol define the
Identifiers or must the using protocol use and authenticate Identifiers or must the using protocol use and authenticate
Pseudonyms proposed by the policies, chosen independently of the Pseudonyms proposed by the Rules, chosen independently of the using
using protocol? Of course, if the using protocol has an appropriate protocol? Of course, if the using protocol has an appropriate
namespace, containing many unused names that may be used as namespace, containing many unused names that may be used as
pseudonyms and may be replaced by new ones regularly, then the pseudonyms and may be replaced by new ones regularly, then the
Location Object may be able to use the name space. For this purpose, Location Object may be able to use the name space. For this purpose,
the user would probably have to write his policies using this name the user would probably have to write his Rules using this name
space. Note that it is necessary to change the used pseudonyms space. Note that it is necessary to change the used pseudonyms
regularly, because identifying the user behind an unlinked pseudonym regularly, because identifying the user behind an unlinked pseudonym
can be very simple. can be very simple.
There are several advantages of letting the using protocol to define There are several advantages of letting the using protocol to define
the name space: the name space:
o the embedded authentication would be easier, as the using protocol o the embedded authentication would be easier, as the using protocol
has often already the credentials for the authentication identity has often already the credentials for the authentication identity
in place and the "embedded" authentication would be independent on in place and the "embedded" authentication would be independent on
the form of Identifiers, the form of Identifiers,
o the size of the names would be fixed. o the size of the names would be fixed.
On the other hand, the benefits of the policy choosing the On the other hand, the benefits of the Rule choosing the identifiers
identifiers are: are:
o the user has a control of his anonymity, and o the user has a control of his anonymity, and
o the interworking of multiple systems with Location object across o the interworking of multiple systems with Location object across
protocol boundaries is facilitated. protocol boundaries is facilitated.
10. Author's Addresses 10. Acknowledgements
We wish to thank the members of the IETF Geopriv WG for their
comments and suggestions. Aaron Burstein, Mehmet Ersue, Allison
Mankin, Randall Gellens, and the participants of the Geopriv
meetings in San Diego and Yokohama provided detailed comments or
text.
11. References
Cuellar, Morris, Mulligan, Peterson, Polk 25
Geopriv Requirements Mar 2003
[Bra00] Stefan A.: Rethinking Public Key Infrastructures and Digital
Certificates : Building in Privacy, MIT Press; ISBN:
0262024918; 1st edition, August, 2000
[Cha85] Chaum, David: Security without Identification, Card
Computers to make Big Brother Obsolete. Original Version
appeared in: Communications of the ACM, vol. 28 no. 10,
October 1985 pp. 1030-1044. Revised version available at
http://www.chaum.com/articles/
[ISO99] ISO99: ISO IS 15408, 1999, http://www.commoncriteria.org/.
[OECD] OECD Guidelines on the Protection of Privacy and Transborder
Flows of Personal Data, http://www.oecd.org.
[Pfi01] Pfitzmann, Andreas; K÷hntopp, Marit: Anonymity,
Unobservability, and Pseudonymity - A Proposal for
Terminology; in: H Federrath (Ed.): Designing Privacy
Enhancing Technologies; Proc. Workshop on Design Issues in
Anonymity and Unobservability; LNCS 2009; 2001; 1-9. Newer
versions available at http://www.koehntopp.de/marit/pub/anon
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
12. Author's Addresses
Jorge R Cuellar Jorge R Cuellar
Siemens AG Siemens AG
Corporate Technology Corporate Technology
CT IC 3 CT IC 3
81730 Munich Email: Jorge.Cuellar@mchp.siemens.de 81730 Munich Email: Jorge.Cuellar@mchp.siemens.de
Germany Germany
John B. Morris, Jr. John B. Morris, Jr.
Director, Internet Standards, Technology & Policy Project Director, Internet Standards, Technology & Privacy Project
Center for Democracy and Technology Center for Democracy and Technology
1634 I Street NW, Suite 1100 1634 I Street NW, Suite 1100
Washington, DC 20006 Email: jmorris@cdt.org Washington, DC 20006 Email: jmorris@cdt.org
USA http://www.cdt.org USA http://www.cdt.org
Deirdre K. Mulligan Deirdre K. Mulligan
Samuelson Law, Technology and Public Policy Clinic Samuelson Law, Technology and Public Privacy Clinic
Boalt Hall School of Law Boalt Hall School of Law
University of California University of California
Berkeley, CA 94720-7 Email: dmulligan@law.berkeley.edu Berkeley, CA 94720-7 Email: dmulligan@law.berkeley.edu
USA
11. Full Copyright Statement Jon Peterson
NeuStar, Inc.
1800 Sutter St
Suite 5707 Email: jon.peterson@neustar.biz
Copyright (C) The Internet Society (date). All Rights Reserved. Cuellar, Morris, Mulligan, Peterson, Polk 26
Geopriv Requirements Mar 2003
Cuellar, Morris, Mulligan 23 Concord, CA 94520 http://www.neustar.biz/
Geopriv Requirements Jan 2003 USA
James M. Polk
Cisco Systems
2200 East President George Bush Turnpike
Richardson, Texas 75082 USA7 Email: jmpolk@cisco.com
13. Full Copyright Statement
Copyright (C) The Internet Society (date). All Rights Reserved.
This document and translations of it may be copied and furnished to This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph kind, provided that the above copyright notice and this paragraph
are included on all such copies and derivative works. However, this are included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of Internet organizations, except as needed for the purpose of
skipping to change at line 1271 skipping to change at line 1421
The limited permissions granted above are perpetual and will not be The limited permissions granted above are perpetual and will not be
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This document and the information contained herein is provided on an This document and the information contained herein is provided on an
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TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Cuellar, Morris, Mulligan 24 Cuellar, Morris, Mulligan, Peterson, Polk 27
 End of changes. 

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