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Internet Draft J. Jorge Cuellar
Document: draft-ietf-geopriv-reqs-02.txt draft-ietf-geopriv-reqs-03.txt Siemens AG

John B. Morris, Jr.
Center for Democracy and Technology

Deirdre Mulligan
Samuelson Law, Technology, and Public Policy Privacy Clinic

Jon Peterson
NeuStar

James Polk
Cisco

Expires in six months Jan Mar 2003

Geopriv requirements

Status of this Memo

This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.

Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.

Internet-Drafts are draft documents valid for a maximum of six
months and may be updated, replaced, or obsoleted by other documents
at any time. It is inappropriate to use Internet-Drafts as
reference material or to cite them other than as "work in progress."

The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.

Abstract

Location-based services, navigation applications, emergency
services, management of equipment in the field, and other location-
dependent services need geographic location information about a

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Geopriv Requirements Mar 2003

Target (such as a user, resource or other entity). There is a need
to securely gather and transfer location information for location
services, while at the same time protecting the privacy of the
individuals involved.

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This document focuses on the authorization, integrity security and privacy
requirements for such location-dependent services. Specifically, it
describes the requirements for the geopriv Geopriv Location Object (used to
securely transfer location data and other privacy-enabling
information) (LO) and
for the protocols that use this Location Object. This LO is
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

1. Overview........................................................3 Overview.......................................................3
2. Conventions used in this document...............................4 document..............................4
3. Terminology.....................................................4
3.1. Foundational Definitions...................................4
3.1.1. Glossary.......................................................4
4. Primary Geopriv Entities.......................................6
5. Further Geopriv Terminology....................................7
5.1. Location Information (LI) and Sighting................4
3.1.2. Sighting.........................7
5.2. The Location Object...................................6
3.1.3. Location Object vs. and Using Protocol....................6
3.1.4. Protocol....................8
5.3. Trusted vs. Non-trusted Data Flows....................6
3.2. Geopriv Entities and Functions.............................7
3.2.1. Primary Geopriv Entities..............................7
3.2.2. Secondary Geopriv Entities............................8
3.2.3. Flows........................9
5.4. Further Geopriv Data Storage Functions........................9
3.3. Principals...............................10
5.5. Privacy Policies and Rules.................................9
3.4. Rules............................................12
5.6. Identifiers, Authentication and Authorization.............10
4. Authorization............12
6. Scenarios and Explanatory Discussion...........................11
4.1. Scenarios of Data Flow....................................11
5. Requirements...................................................14
5.1. Discussion..........................13
7. Requirements..................................................17
7.1. Location Object...........................................15
5.2. Object..........................................17
7.2. The Using Protocol........................................16
5.3. Policy Protocol.......................................19
7.3. Rule based Location Data Transfer.......................17
5.4. Transfer........................20
7.4. Location Object Privacy and Security......................18
5.5. Security.....................21
7.4.1. Identity Protection.......................................18
5.6. Protection.................................21
7.4.2. Authentication Requirements...............................18
5.7. Requirements.........................21
7.4.3. Actions to be secured.....................................18
5.8. Non-Requirements..........................................19
6. secured...............................21
7.5. Non-Requirements.........................................22
8. Security Considerations........................................19
6.1. Considerations.......................................22
8.1. Traffic Analysis..........................................19
6.2. Analysis.........................................22
8.2. Securing the Privacy Policies.............................19
6.3. Rules...............................22
8.3. Emergency Case............................................20
6.4. Case...........................................23
8.4. Identities and Anonymity..................................20
6.5. Anonymity.................................23
8.5. Unintended Target.........................................21
7. Acknowledgements...............................................21
8. References.....................................................21 Target........................................24
9. Protocol and LO Issues for later Consideration.................22 Consideration................24
9.1. Multiple Locations in one LO..............................22 LO.............................24
9.2. Translation Fields........................................22 Fields.......................................24
9.3. Specifying Desired Accuracy in a Request..................22
9.4. Truth Flag................................................22 Flag...............................................25
9.4. Timing Information Format................................25

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9.5. Timing Information Format.................................22
9.6. The Name Space of Identifiers.............................22 Identifiers............................25
10. Author's Addresses............................................23 Acknowledgements.............................................25
11. References...................................................25
12. Author's Addresses...........................................26
13. Full Copyright Statement......................................23 Statement.....................................27

1. Overview

Location-based services (applications that require geographic
location information as input) are becoming increasingly common.
The collection and transfer of location information about a
particular Device and/or Target can have important privacy implications. A key
goal of the protocols protocol described in this document is to facilitate the
protection of privacy pursuant to
privacy policies Privacy Rules set by the "user"
"user/owner of the Target" (or, more precisely in the terminology of
this document defined given in Section 3 and 5.4 below, the "Rule Maker").

The ability to derive or compute gather and generate a Device's Target's location, and access
to the derived or computed location, are key elements of the location-
based
location-based services privacy equation. Central to a Target's
privacy are (a) the identity of entities that have access to raw
location data, derive or compute location, and/or have access to
derived or computed location information, and (b) whether those
entities can be trusted to know and follow the privacy policy Privacy Rules of the
user.

The main principles guiding the requirements described in this
document are:

1) Security of the transmission of Location Object is essential to
guarantee the integrity and confidentiality of the location
information. This includes authenticating the sender and
receiver of the Location Object, and securing the Location Object
itself.

2) A critical role is played by user-controlled policies, Privacy Rules, which
describe the restrictions imposed or permissions given by the
"user" (or, as defined below, the "Rule Maker"). The policies Privacy
Rules specify the necessary conditions that allow a Location
Server to forward Location Information to a Location Recipient,
and the conditions under which and purposes for which the
Location Information can be used.

3) One type of Privacy Rules specify in particular how location
information should be filtered, depending on who the recipient
is. Filtering is the process of reducing the precision or
resolution of the data. A typical rule may be of the form: "my
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").

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4) The Location Object should be able to carry a limited but core
set of privacy policies. Privacy Rules. The exact form or expressiveness of
policies those
Rules in the core set or in the full set is not further discussed
in this paper, document, but is will be discussed more extensively in a
separate document.

4)
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 (e.g., the (i.e.,
Personally Identifiable Information such as a name, mailing
address, phone number). number, social security number, or email address
or username). Rather, the user should be able to specify which

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local identifier, unlinked pseudonym, or private identifier is to
be bound to the location information.

6) The user may want to hide the real identities of himself and his
partners not only to eavesdroppers but also to other entities
participating in the protocol.

Although complete anonymity may not be appropriate for some
applications because of legal constraints or because some location
services may in fact need explicit identifications, in most cases
the location services only need some type of authorization
information and/or perhaps anonymous identifiers of the entities in
question.

2. Conventions used in this document

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in [RFC2119].

Note that the requirements discussed here are requirements on the
generic Location Object and on the using protocols for location
services. Thus Thus, for the most part, the requirements discussed in
this document mostly refer to the capabilities that are mandatory-to-implement.
For example, requiring that implementations support integrity is not
the same thing as requiring that all protocol traffic be
authenticated. In other cases, the contrast, an example of a mandatory-to-use (not
just mandatory-to-implement) requirement may might be one that states
that the user always obtains receives a notice when his location data was
not authenticated. This practice is mandatory-to-use, not just to
implement.

3. Glossary

For easy reference and readability, below are basic terms that will
be defined more formally and fully later in this document.

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.

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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 �push� rules to a location server,
or a location server may �pull� 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

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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.

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.

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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 (1) terms
that, besides the primary Geopriv entities, (1) are used in the
requirements section of this document, and (2)
terms that provide additional
detail about the usage model envisioned for the geopriv Geopriv Location
Object. These latter terms will be utilized in a separate scenarios document.

3.1. Foundational Definitions

3.1.1.
document and elsewhere.

5.1. Location Information (LI) and Sighting

The focus of the geopriv Geopriv working group is on information about a
Target's location that is NOT based on generally or publicly
available sources, but instead on private information provided or
created by a Target, a Target's Device, or a Target's network or
service provider: provider. Notwithstanding this focus on private location
information, the Geopriv Location Information (LI): Object could certainly be used to
convey location information from publicly available sources.

Location Information: A relatively specific way of describing
where a Device is
located and that is located.

This Location Information may have determined in many different
ways, including:
(a) derived or computed from information generally not available to
the general public (such as

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Geopriv Requirements Jan 2003 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.

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As examples, LI the Location Information could include (a) information
calculated by triangulating on a wireless signal with respect to
cell phone towers, (b) longitude and latitude information determined
by a Device with GPS (global positioning satellite) capabilities, or
(c) information manually entered into a cell phone or laptop by a
Target in response to a query. 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
information wholly without the knowledge or consent of the Target
(or the Target's network or access service provider), based on
generally available information such as an IP or e-mail address. In
some cases information like IP address can enable someone to
estimate (at least roughly) a location. Commercial services exist
that offer to provide rough location information based on IP
address. Currently, this type of location information is typically
less accurate and has a coarser granularity precise than the type of location information addressed in this
document. Although this type of location computation still raises
significant potential privacy and public policy privacy concerns, such
scenarios are generally outside the scope of this document.

Within any given location-based transaction, the INITIAL
determination of location (and thus the initial creation of Location
Information) is termed a Sighting:

Sighting:
The initial determination of location based on non-public
information (as discussed in the definition of Location
Information), and the initial creation of Location
Information.

Some variant of the sighting information is included in the Location
Object. Abstractly, it consists of two separate data fields:

(Identifier, Location)

where Identifier is the identifier assigned to a 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
of sighting information. A sighting may be transformed to a new
sighting pair:

(Identifier-1, Location-1)

before it is provided by a Location Sighter Generator or Location Server to
another Location Recipient (for instance, another
Location Server).

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Geopriv Requirements Jan 2003 Recipient. In this case, Identifier-1 may be Pseudonym,
and Location-1 may have less accuracy precision or granularity resolution than the
original value.

3.1.2.

5.2. The Location Object and Using Protocol

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A main goal of the geopriv Geopriv working group is to define a Location
Object (LO), to be used to convey both Location Information and
basic privacy-protecting instructions:

Location Object (LO): This data contains the Location Information
of the Target, and other fields including an identity or
pseudonym of the Target, time information, core privacy
policies, Privacy Rules,
authenticators, etc. Most of the fields are optional,
including the Location Information itself.

Nothing is said about the semantics of a missing field. For
instance, a partially filled object MAY be understood implicitly as
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
time", but it could be interpreted in a different way, depending on
the context.

3.1.3. Location Object vs. Using Protocol

The "using protocol" is the protocol that uses (creates, reads (reads or modifies)
the Location Object. A protocol that just transports the LO as a
string of bits, without looking at them (like an IP storage protocol
could do), is not a using protocol, but only a transport protocol.
Nevertheless, the entity or protocol that caused the transport
protocol to move the LO is responsible of for the correct appropriate
distribution, protection, usage, retention, and storage of the LO
based on the rules that apply to that LO.

The security and privacy enhancing mechanisms used to protect the LO
are of two types: First, the Location Object definition MUST
include (optional) the fields or mechanisms used to secure the LO as such. The
LO MAY be secured, for example, using cryptographic checksums or
encryption as part of the LO itself. Second, the using protocol may
also provide security mechanisms to securely transport the Location
Object.

The

When defining the LO, the design should observe that the security
mechanisms of the Location Object itself are to be preferred.

3.1.4. 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).

5.3. Trusted vs. Non-trusted Data Flows

Location information can be used in very different environments. In
some cases the participants will have longstanding relationships,
while in others the participants may have discrete interactions with
no prior contractual or other contact.

The different relationships raise different concerns for the
implementation of privacy rules, including the need to communicate

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privacy policies.
Privacy Rules. A public Rule Repository, Holder, for example, may be
unnecessary in a trusted environment where more efficient methods of

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addressing privacy issues exist. The following terms distinguish
between the two basic types of data flows:

Trusted Data Flow:
A data flow that is governed by a pre-existing contractual
relationship that addresses location privacy.

Non-trusted Data Flow:
The data flow is not governed by a pre-existing contractual
relationship that addresses location privacy.

3.2. Geopriv Entities and Functions

The entities of a geopriv application or transaction may be given
explicit roles:

3.2.1. Primary

5.4. Further Geopriv Entities

Certain entities and roles are involved in most (and in some cases
all) geopriv transactions: Principals

Target:
The entity whose location is desired by the Location Seeker.
Recipient. In many cases the Target will be the human "user"
of a Device or an object such as a vehicle or shipping
container to which the Device is attached. In some instances
the Target will be the Device itself.

Device:
The technical device the location of which is tracked as a
proxy for the location of a Target.

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: Maker (RM):
The individual or entity that has the authorization to set the
applicable privacy policies and rules. Privacy Rules for a potential Geopriv Target. In
many cases this will be the owner of the Device, and in other
cases this may be the user who is in possession of the Device.
For example, parents may control what happens to the location
information derived from a child's cell phone. A company, in
contrast, may own and provide a cell phone to an employee but
permit the employee to set the privacy rules.

There are four scenarios in which some form of constraint or
override might be placed on the Privacy Rules of the Rule
Maker:

1. In the case of emergency services (such as E911 within the
United States), local or national laws may require that
accurate location information be transmitted in certain
defined emergency call situations. The Geopriv Working Group
MUST facilitate this situation.

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Location Seeker (LSeek):
An individual or entity who seeks to receive location data
about a Target.

A Location Seeker Requirements Mar 2003

2. In the case of legal interception, the RM may act in one or more not be aware
of an override directive imposed by a legal authority. It is
not the following more
specialized roles: as expectation of the Location Sighter, a Location Server, or as Working Group that particular
accommodation will be made to facilitate this situation.

3. In the context of an Ultimate Location Recipient:

Location Sighter (LoSi), employment relationship or Location Data-Source
The original source of other
contractual relationship, the sighting owner of a Target in particular location
(such as a given
transaction.

Location Server (LServ), or Intermediate Location Recipient:
A Device or entity that provides access to Location
Information (possibly after processing or altering it) in
accordance with corporate campus) may impose constraints on the privacy policies use
of the Privacy Rules by a Rule Maker. Some
location tracking scenarios may involve It is not the expectation
of the Working Group that particular accommodation will be
made to facilitate this situation.

4. It is conceivable that a Target, Device, or
Device user performing governmental authority may seek to
impose constraints on the function use of Privacy Rules by a Location Server.

Ultimate Location Recipient (ULR): 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
Target and does not transmit the location information or
information based on the Target's location (such as driving
directions to or from the Target) to any party OTHER than the
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:
An entity or network that receives and forwards data without
processing or altering it. A Data Transporter could
theoretically be involved in almost any transmission between a
Device and a Location Server, a Location Server and a second
Location Server, or a Location Server and an Ultimate Location
Recipient. Viewer. Some
location tracking scenarios may not involve a Data
Transporter.

Initial

Access Provider (IAP): (AP):
The entity domain that provides the initial network access or other
data communications services essential for the operation of
communications functions of the Device or computer equipment
in which the Device operates. Often, the IAP AP -- which will be
a wireless carrier, an Internet Service Provider, or an
internal corporate network -- will be identical to contains the LoSi.
In other cases LG. Sometimes the IAP
AP has a "dumb" LoSi, LG, one that transmits
geopriv data Geopriv LOs but does
not implement or use any part of the
geopriv Location Object. Other cases may involve no IAP at
all or the IAP is only a Data Transporter.

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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 part of the scope of this document, but see Geopriv Location Object. Other cases
may not involve any AP, or the remarks in Section 6
(Privacy Considerations). AP may only act as a Data
Transporter.

Location Storage:
A Device or entity that stores raw or processed Location
Information
Information, such as a database, for any period of time longer
than the duration necessary to complete an immediate
transaction regarding the
LI. Location Information.

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The existence and data storage practices of Location Storage is
crucial to privacy considerations, because this may influence what
Location Information could eventually be revealed (through later
distribution, technical breach, or legal processes).

3.3.

5.5. Privacy Policies and Rules

Privacy Policies Rules are rules that regulate an entity's activities with
respect to location and other information, including, but not
limited to, the collection, use, disclosure, and retention of
location information. Such rules are generally based on fair
information practices, as detailed in (for example) the OECD
Guidelines on the Protection of Privacy and Transporter Flows of
Personal Data [OECD].

Privacy Policy or Privacy Rule:
A rule or set of rules that regulate an entity's activities
with respect to location information, including the
collection, use, disclosure, and retention of location
information. In particular, the policy Rule describes how location
information may be used by an entity and which transformed
location information may be released to which entities under
which conditions. Policies Rules must be obeyed; they are not
advisory.

A full set of Privacy Rules will likely include both rules that have
only one possible technical meaning, and rules that will be affected
by a locality's prevailing laws and customs. For example, a
distribution rule of the form "my location can only be disclosed to
the owner of such credentials and in such accuracy" precision or resolution"
has clear-cut implications for the protocol that uses the LO. But
other rules,

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Geopriv Requirements Jan 2003 like retention or usage policies, Rules, may have unclear
technical 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.

5.6. Identifiers, Authentication and Authorization

Anonymity is the property of being not identifiable (within a set of
subjects). Anonymity serves as the base case for privacy: without
the ability to remain anonymous, individuals cannot may be unable to
control their own privacy. Unlinkability ensures that a user may
make multiple uses of resources or services without others being
able to link these uses together. to each other. Unlinkability requires that
entities are unable to determine whether the same user caused
certain specific operations in the system. [ISO99] A pseudonym is
simply a bit string which is unique as ID and is suitable to be used
for end-
point end-point authentication.

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Unlinked Pseudonym:
A pseudonym where the linking between the pseudonym and its
holder is, at least initially, not known to anybody with the
possible exception of the holder himself or a trusted server
of the user. See [Pfi01] (there the term is called Initially
Unlinked Pseudonym)

The word authentication is used in different meanings. Some require
that authentication associates an entity with a more or less well-
known identity. This basically means that if A authenticates
another entity B as being "id-B", then the label "id-B" is a well-
known, or at least a linkable identity of the entity. In this case,
the label "id-B" is called a publicly known identifier, and the
authentication is "explicit":

Explicit Authentication:
The act of verifying a claimed identity as the sole originator
of a message (message authentication) or as the end-point of a
channel (entity authentication). Moreover, this identity is
easily linked back to the real identity of the entity in
question, for instance being a pre-existing static label from
a predefined name space (telephone number, name, etc.).

Authorization

Authorization:
The act of determining if a particular right, such as access
to some resource, can be granted to the presenter of a
particular credential.

Depending on the type of credential, authorization may imply
Explicit Authentication or not.

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6. Scenarios and Explanatory Discussion

4.1. Scenarios of Data Flow

In this subsection we introduce short scenarios to illustrate how
these terms and attributes describe location information
transactions. Additional illustrative scenarios are discussed in a
separate Document.

SCENARIO 1: GPS Device with Internal Computing Power: Closed System

In this example, the Target wishes to know his/her location using
Global Positioning System (GPS) and the Device is capable of
independently processing the raw data to determine its location.
The location is derived as follows: the Device receives
transmissions from the GPS satellites, internally computes and
displays location. This is a closed system. For the purpose of this
and subsequent examples, it is assumed that the GPS satellite
broadcasts some signal, and has no information about the identity or
whereabouts of Devices using the signal.

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Geopriv Requirements Mar 2003

GPS Satellite
|
| Sighting (not a Geopriv Interface)
|
|
|
V GPS Device
--------------------------------------------------
/ \
| Data Location ----- Location ----- Location |
| Transporter Generator Server Storage |
\ | /
-------------------------------------------|------
|
| Notification
| Interface
|
------------|------
/ V \
/ Target Location \
| Seeker Recipient |
| |
\ Rule Maker /
\ /
-------------------

In this scenario the GPS Device is both the IAP AP and the LoSi. LG. The
interaction occurs in a Trusted environment because it occurs in the
Rule Maker�s Device.

SCENARIO 2: Cell Phone Roaming

In this example, a cell phone is used outside its home service area
(roaming). Also, the cell phone service provider (cell phone Corp 2)

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Geopriv Requirements Jan 2003
outsourced the accounting of cell phone usage. The cell phone is not
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 cell phone, cell phone Corp 1 (IAP) (AP) provides the roaming service
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
home service provider. Cell phone Corp 2 submits the raw data to
the accounting company, which processes the raw data for the
accounting statements. Finally, the raw data is sent to a data
warehouse where the raw data is stored in a Location Server (e.g.,
computer server).

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Geopriv Requirements Mar 2003

Cell Phone Corp 1 Cell Phone Corp 2
----------------- -----------------
Sighting / \ Sighting Publish / \
Device ----- | Data Transporter | --------- | Data Transporter |
Target \ / Interface \ /
----------------- / -----------------
/ |
/ sighting| | Notification
/ | Interface
----------- |
/ V
------------ / ----------
/ \ / / \
/ Location \ / | Location |
| Storage | Location Info | Storage |
| |<----------------- | |
| Location | | Location |
| Seeker Recipient | | Seeker Recipient |
\ / \ /
------------- ----------

Here cell phone corp Corp 1 is the IAP AP and the LoSi. LG. In this scenario, Cell
phone corp 1
could Corp 2 is likely to be Non-trusted (the Rule Maker does not have a contract
protecting location information with corp 1 and there is no
contractual relationship with privacy provisions between corp 1 and
corp 2) or Trusted (contract with privacy protections between entity, but cell phone corp 2 and corp 1). Cell phone corp 2 is Trusted. Corp
1 may be Non-trusted.

SCENARIO 3: Mobile Communities and Location-Based Services

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
or with a Location-Based Service Provider. Some of the messages use
a Location Object to carry carry, for instance: instance, identities or pseudonyms,
credentials and proof-of-possession of them, Policies Rules and Location Data
Information, including Data Types and Accuracy. They are shown
in the figure by normal arrows ("--->"). Other messages Precision or Resolution.
Messages that do not use

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Geopriv Requirements Jan 2003 the Location Object and are outside of the
scope of the geopriv Geopriv WG, but should be mentioned for understandability. They
understandability, are shown in the figure as starred arrows
("***>").

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Geopriv Requirements Mar 2003

+---------+ +------------+
| Location| | Public | | Data |<** | Policy
| Location|<** | Source Public |
|Generator| * | Repository | Rule Holder|
| + IAP | * +------------+ | |
+---------+\ * * *
^ +------------+
\ *5 3a* * *3 1a* *
\ * * *
*
\ ** *
*
\ * * *3a
5a * *1a
\* * *
* * \ * *
* * \ * *
* \4 * \6 *
*
+----------+ * \ * V
| Target |
* \->+-----------+
|
+----------+ 3 1 | Location |
+-|
| Rule |--------------------->| Server + |
| Maker | | Private |
+----------+<********************>| Repository|
^ 1
+----------+ |Rule Holder|
+-----------+
|
^ |
| 4| |7
|
3| |5
| V
|
+----------+
| | Ultimate |
+---------------------------->| Location |
2 | Recipient|
+----------+

Figure 1: The Entities and Data Flows

1: Registration:
The
| Recipient|
+----------+

Assume that the Rule Maker registers himself and the Target are registered with the
Location Server. This registration process is outside of the
scope of our discussion, but probably the Rule Maker The RM has somehow proven to
prove the LS that he indeed
is the owner of the privacy rights of the Target (the Target is
usually a Device owned by the Rule Maker). The Rule Maker and the
Location Server agree, as part
of have agreed on the Registration Process, which set of keys or credentials and
proof-of-possession of the corresponding secrets
cryptographic material that 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.

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2: End-to-End Negotiation:
The Rule Maker and the Location Seeker exchange information
about the service (if any) and negotiate it. They also
negotiate the pseudonyms that they will use later on and the
credentials or keys that the Ultimate Location Recipient will
use to prove his authorization to Rules. How
this has been done is outside of the Location Server. This
End-to-End Negotiation may contain several messages and may
use or not scope of the Location Object.

3: Policy document.

1: Rule Transfer:
The Rule Maker sends a Policy Rule to the Location Server. This
Policy Rule
may be a field in a Location Object or not.

3a:Signed Policy:

1a:Signed Rule:
As an alternative to the Policy Transfer, alternative, the Rule Maker may write a policy Rule and place
it in the Open Repository. a Public Rule Holder. The entities access the
repository to read the signed policies.

4: Rules.

2: Location Information Request:
The Location Seeker Recipient requests location information for a

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Target. In this request, the Location Seeker Recipient may select
which location information data type it prefers. One way of
requesting Location Information MAY be sending a partially
filled Location Object, including only the identities of the
Target and Location Recipient and the desired Data Type and
accuracy,
precision or resolution, and providing proof of possession of
the required credentials. But whether the using protocol
understands this partially filled object as a request, this
MAY depend on the using protocol or on the context. The
Location Seeker Recipient could also specify the need for periodic
location information updates, but this is probably out of the
scope of geopriv.

5: Geopriv.

3: Locate:
When a Location Server receives an Location Information
Request for a Target for which has no current location
information, the server may send ask the Location Sighter Generator to
locate the Target.

4: Location Information:
The Location Sighter Generator sends the "full" location information
to the Location Server. This Location Information may be
embedded in a Location Object or not.

5: Filtered Location Information:
Then the Location Server sends Location Server sends the location information to the
Location Recipient. The information may be filtered in the
sense that in general a less precise or a computed version of
the information is being delivered.

7. Requirements

7.1. 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 location information to LO MUST define the
Location Recipient. The information may be filtered in LO field 'A',
o the
sense that in general a less precise field 'A' MAY be defined as optional or a computed version not to use. If it is
defined as optional to use, any instance of a LO MAY contain the information
field 'A' or not; if it is being delivered.

5. Requirements not optional, all instances of LOs MUST
contain the field 'A'.

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Geopriv Requirements Jan Mar 2003

5.1. Location Object

Req. 1. (Location Object generalities)

1.1) Geopriv MUST define one Location Object (LO) -- both in
syntax and semantics -- that must be supported by all geopriv Geopriv
entities.

1.2) Some fields of the Location Object MAY be optional. This
means that an instance of a Location Object MAY contain the
fields or not.

1.3) Some fields of the Location Object MAY be defined as
"extensions". This means that the syntax or semantics of these
fields is not fully defined in the basic Location Object
definition, but their use may be private to one or more using
protocols.

1.4) The Location Object MUST be extensible, allowing the
definition of new attributes or fields.

1.5) The object MUST be suitable for requesting and receiving a
location.

1.6) The object MUST permit (but not require) the policy Privacy Rules
to be enforced by a third party.

1.7) The object MUST be usable in a variety of protocols, such as
HTTP and SIP, as well as local APIs.

1.8) The object MUST be usable in a secure manner even by
applications on constrained devices.

Req. 2. (Location Object fields) The Location Object definition
MUST support contain the following Fields (but not all LOs must use all
fields) Fields, which MAY be optional to use:

2.1) Target Identifier

2.2) Location Recipient Identity

This identity may be a multicast or group identity, used to
include the Location Object in multicast-based using protocols.

2.3) Location Recipient Credential

2.4) Location Recipient Proof-of-Possession of the Credential

2.5) Location Field.

2.5.1) Motion and direction vectors. This field MUST be
optional.

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Each Location Field may contain one or more Location
Representations, which can be also in different formats.

2.6) Location Data Type

When transmitting the Location Object, the sender and the
receiver must agree on the data type of the location information.
The using protocol may specify that the data type information is
part of the Location Object or that sender and receiver have
agreed on it before the actual data transfer.

2.7) Motion and direction vectors

2.8) Timing information:
(a) When was the LI Location Information accurate? (sighting time)
(b) Until when considered current? TTL (Time-to-live) (This is
different than a privacy rule setting a limit on data retention)

2.9) Policy

2.8) Rule Field: this field MAY be a referral to an applicable
policy
Rule (for instance, an URI to a full policy), Rule), or it MAY contain a
Limited Policy Rule (see Req. 9), 11), or both.

2.10)

2.9) Security-headers and -trailers (for instance encryption
information, hashes, or signatures) (see Req. 13).

2.11) 14 and 15).

2.10) Version number

Req. 3. (Location Data Types)

3.1) The Location Object MUST define at least one Location Data
Type to be supported by all geopriv Geopriv receivers (entities that
receive LOs).

3.2) The Location Object SHOULD define two Location Data Types:
one for latitude / longitude / altitude coordinates and one for
civil locations (City, Street, Number) supported by all geopriv Geopriv
receivers (entities that receive LOs).

3.3) The latitude / longitude / altitude Data Type SHOULD also
support a delta format in addition to an absolute one, used for
the purpose of reducing the size of the packages or the security
and confidentiality needs.

3.4) The Location Object definition SHOULD agree on further
Location Data Types supported by some geopriv Geopriv entities and
defined by other organizations.

5.2.

7.2. The Using Protocol

Req. 4. The using protocol has to obey the privacy and security
instructions coded in the Location Object and in the

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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
associated with the credentials are transported to the respective

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parties, that is, key agreement is responsibility of the using
protocol.

Req. 6. (Single Message Transfer) In particular for tracking of
small target devices, the design should allow a single
message/packet transmission of location as a complete
transaction.

Other requirements on the using protocol are out of the scope of
this document. document, but might be the subject of future efforts from this
working group. See also Section 9 (Protocol and LO Issues for later
Consideration)

5.3. Policy

7.3. Rule based Location Data Transfer

Req. 7. (LServ Policies) (LS Rules) The decision of a Location Server to provide a
Location Seeker Recipient access to Location Information MUST be based
on Rule Maker-defined Privacy Policies. Rules.

It is outside of our scope how Privacy Policies Rules are managed, managed and how a
Location Server has access to the Privacy Policies, and if he is or
not aware of the full set of rules desired by the Rule-Maker. Rules. Note that it might
be that some rules contain private information not intended for
untrusted parties.

Req. 8. (LoSi Policies) (LG Rules) Even if a Location Sighter Generator is unaware of and
lacks access to the full Privacy Policies Rules defined by the Rule Maker,
the Location Sighter Generator MUST transmit Location Information in
compliance with instructions set by the Rule Maker. Such
compliance MAY be accomplished by the Location Sighter Generator
transmitting LI the LO only to a URI designated by the Rule Maker.

Req. 9. (ULR Policies) (Viewer Rules) An Ultimate Location Recipient Viewer does not need to be aware of the
full policies Rules defined by the Rule Maker (because an ULR Viewer SHOULD
NOT retransmit Location Information), and thus an ULR Viewer SHOULD
receive only the subset of Privacy Policies Rules necessary for the ULR Viewer
to handle the LI LO in compliance with the full Privacy Policies Rules (such
as, for example, an instruction on the time period for which then LI
the LO can be retained).

Req. 10. (Full Policy Rule language) Geopriv MAY specify a policy Rule language
capable of expressing a wide range of privacy rules concerning
location information. This policy Rule language MAY be an existing one,
an adaptation of an existing one or a new policy Rule language, and it
SHOULD be as simple as possible.

Req. 11. (Limited Policy Rule language) Geopriv MUST specify a limited
policy
Rule language capable of expressing a limited set of privacy

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Geopriv Requirements Jan 2003
rules concerning location information. This policy Rule language MAY be
an existing one, an adaptation of an existing one or a new
policy Rule
language. The Location Object MUST include sufficient fields and
data to express the limited set of privacy rules.

5.4.

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7.4. Location Object Privacy and Security

5.5.

7.4.1. Identity Protection

Req. 12. (Identity Protection) The Location Object MUST support use
of Unlinked Pseudonyms in the corresponding identification fields
of Rule Maker, Target, Device, and Location Recipient. Since
Unlinked Pseudonyms are simply bit strings that are not linked
initially to a well-known identity, this requirement boils down
to saying that the name space for Identifiers used in the LO has
to be large enough to contain many unused strings.

5.6.

7.4.2. Authentication Requirements

Req. 13. (Credential Requirements) The using protocol and the
Location Object SHOULD allow the use of different credentials
types, including privacy-enhancing credentials (like for instance
the ones described in [Bra00] or [Cha85]).

5.7.

7.4.3. Actions to be secured

Req. 14. (Security Features) The Location Object MUST support
fields suitable for protecting the Object to provide the
following security features:

14.1) Mutual end-point authentication: the using protocol is
able to authenticate both parties in a Location Object
transmission,

14.2) Data object integrity: the LO is secured from
modification by unauthorized entities during transmission and
during storage,

14.3) Data object confidentiality: the LO is secured from
eavesdropping (unauthorized reading) during transmission and
during storage, and

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
perhaps during a small window of time that is configurable or
accepted by the Rule Maker).

Req. 15. (Minimal Crypto)

15.1) Geopriv MUST specify a minimum mandatory to implement
Location Object security including mandatory to implement crypto

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Geopriv Requirements Jan 2003
algorithms, for digital signature algorithms and encryption
algorithms.

15.2) It MAY also define further mandatory to implement
Location Object security mechanisms for message authentication
codes (MACs) or other purposes.

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15.3) The protocol SHOULD allow a bypass if authentication
fails in an emergency call.

The issue addressed in the last point is that an emergency call in
some very unfavorable situations my may not be completed if the minimal
authentication fails. This is probably not what the user would like
to see. happen. The user may prefer an unauthenticated call to an
unauthenticated emergency server than over no call completion at all,
even at the risk that he is talking to an attacker or that his
information is not secured.

5.8.

7.5. Non-Requirements

Non-Req. 1. (Bridging to non-IP networks) The geopriv Geopriv specification
SHOULD NOT specify the bridging to non-IP networks (PSTN, etc).

8. Security Considerations

The purpose of the geopriv Geopriv Location Object and the requirements on
the using protocol are to allow a policy-controlled Privacy Rule-controlled disclosure
of location information for location services.

6.1.

8.1. Traffic Analysis

The information carried within the Location Object is secured in a
way compliant with the privacy and security policies Rules of the Rule Maker,
but other information, carried in other objects or headers are in
general not secured in the same way. This means that geopriv
does Geopriv may
not as a general matter secure the Target against general traffic
analysis attacks or other forms of privacy violations.

6.2.

8.2. Securing the Privacy Policies Rules

The Privacy Policies Rules of the Rule Maker regarding the location of the
Target may be accessible to a Location Server in a Private Storage public or in a Public Repository, non-
public Rule Holder, or they may be carried by the Location Object,
or they may be presented by the Location Seeker Recipient as capabilities
or tokens. Each of this types of policy Rule has to be secured it�s it's own
particular way.

The rules in a Private Storage non-public Rule Holder are typically authenticated
using a MAC (Message Authentication Code) or a signature, depending
on the type of keys used. The rules in a Public Repository public Rule Holder (one
that in

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Geopriv Requirements Jan 2003 principle may be accessed directly by several entities, for
instance several Location Servers) are typically digitally signed. A Policy
Field
Rule Fields in a LO is are secured as part of the LO itself. A Geopriv
Token (a token or ticket issued by the Rule Maker to a Location Seeker,
Recipient, expressing the explicit consent of the Rule Maker to
access his location information) is authenticated or signed.

6.3.

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Geopriv Requirements Mar 2003

8.3. Emergency Case

One

Let us consider the situation where the authentication fails in an
emergency call because the authentication center fails to
authenticate itself. In this case, one way of implementing the
authentication bypass for emergency calls, mentioned in Req 14.3) 15.3) is
to let the user have the choice of writing a policy Rule that says:
- "If the emergency server does not authenticate itself,
nevertheless send the location",
location information anyway", or
- "If the emergency server does not authenticate itself, let the
call fail".

Second, in the case where the authentication of the emergency call
fails because the user may not authenticate itself, the question
arises: whose policy Rule to use? It is reasonable to use a default one:
this location information can only be sent to an emergency center.

Another

The third situation, which should be studied in more detail detail, is:
what to do if not only the user fails to authenticate itself, but
also the emergency center is not authenticable? It is reasonable to
send the Location Information anyway, but are there in this case any
security threats that must be considered?

6.4.

8.4. Identities and Anonymity

The use of Unlinked Pseudonyms is necessary to obtain anonymity.

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
Maker, the Target, and the Device, the and to Location Servers or Location Recipients.
Recipients, if required by the RM. Also, the using protocol SHOULD
be able to hide the real identity of the Location Recipient to the
Location Server.

In this last case, the Target is not concerned about the Server
identifying him and knowing his location, but identifying his
business partners, and therefore his habits, etc. Reasons for
hiding the real identities of the Location Recipients include (a)
that this knowledge may be used to infer the identity of the Target,
(b) that knowledge of the identity of the Location Recipient may
embarrass the Target or breach confidential information, and (c)
that the dossier telling who has obtained a Target's location
information over a long period of time can give information on
habits, movements, etc. Even if the location service providers
agree to respect the privacy of the user, are compelled by laws or
regulations to protect the privacy of the user, and misbehavior or

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Geopriv Requirements Jan 2003
negligence of the Location Server can be ruled out, there is still
risk that personal data may become available to unauthorized persons
through attacks from outsiders, unauthorized access from insiders,
technical or human errors, or legal processes.

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Geopriv Requirements Mar 2003

In some occasions a Location Server has to know who is supplying
policies the
Privacy Rules for a particular Target, but in other situations it
could be enough to know that the supplier of the policies Rules is authorized
to do so. Those considerations are outside of our scope.

6.5.

8.5. Unintended Target

An Unintended Target is a person or object tracked by proximity to
the Target. This special case most frequently occurs if the Target
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
company may not care about the driver's location, but the driver's
privacy is implicitly affected.

Geopriv may or may not protect or affect the privacy of Unintended
Targets, but the impact on Unintended Targets should be
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 rental
company may not care about 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 driver's location, but the driver's
privacy is implicitly affected.

Geopriv Requirements Jan 2003

Enhancing Technologies; Proc. Workshop may or may not protect or affect the privacy of Unintended
Targets, but the impact 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. Unintended Targets should be
acknowledged.

9. Protocol and LO Issues for later Consideration

It seems important to mention some

This section briefly discusses issues on relating to the Location
Object or
on the protocol, which protocol that have emerged during the discussion of
earlier versions of this document.

9.1. Multiple Locations in one LO

A location Field is intended to represent one point or one region in
space (either 1, 2, or 3 dimensionally). The possibility of
inclusion of multiple locations is discussed in another draft, draft-morris-geopriv-location-object-issues-00.txt.

An instance of a document.
The current rough consensus is the following: the LO definition MAY
allow the Location Object could contain zero, one, Field to be optional, to appear exactly one time
or to occur several times. Each Location Fields, perhaps in Field may contain one or
more "Location Representations", each of which is intended to
represent a different formats. Several 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
formats, or multiple sightings at different times, or multiple
sensor locations for the same device, or other purposes. purposes, which could
also depend on the using protocol. This all is for further
discussion.

9.2. Translation Fields

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
possible to have a field to identify the translator, as identity and
method.

9.3. Specifying Desired Accuracy in a Request

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. and
method.

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Geopriv Requirements Mar 2003

9.3. Truth Flag

Geopriv should MUST be silent on the truth or lack-of-truth of the location
information contained in the LO. Thus, the LO MUST not provide an
attribute in object saying "I'm not "I am (or am not) telling you the whole
truth."

9.5.

9.4. Timing Information Format

The format of timing information is out of the scope of this
document.

9.6.

9.5. The Name Space of Identifiers

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Geopriv Requirements Jan 2003

Who defines the Identities: may the using protocol define the
Identifiers or must the using protocol use and authenticate
Pseudonyms proposed by the policies, Rules, chosen independently of the using
protocol? Of course, if the using protocol has an appropriate
namespace, containing many unused names that may be used as
pseudonyms and may be replaced by new ones regularly, then the
Location Object may be able to use the name space. For this purpose,
the user would probably have to write his policies Rules using this name
space. Note that it is necessary to change the used pseudonyms
regularly, because identifying the user behind an unlinked pseudonym
can be very simple.

There are several advantages of letting the using protocol to define
the name space:
o the embedded authentication would be easier, as the using protocol
has often already the credentials for the authentication identity
in place and the "embedded" authentication would be independent on
the form of Identifiers,
o the size of the names would be fixed.

On the other hand, the benefits of the policy Rule choosing the identifiers
are:
o the user has a control of his anonymity, and
o the interworking of multiple systems with Location object across
protocol boundaries is facilitated.

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
Siemens AG
Corporate Technology
CT IC 3
81730 Munich Email: Jorge.Cuellar@mchp.siemens.de
Germany

John B. Morris, Jr.
Director, Internet Standards, Technology & Policy Privacy Project
Center for Democracy and Technology
1634 I Street NW, Suite 1100
Washington, DC 20006 Email: jmorris@cdt.org
USA http://www.cdt.org

Deirdre K. Mulligan
Samuelson Law, Technology and Public Policy Privacy Clinic
Boalt Hall School of Law
University of California
Berkeley, CA 94720-7 Email: dmulligan@law.berkeley.edu

11.
USA

Jon Peterson
NeuStar, Inc.
1800 Sutter St
Suite 5707 Email: jon.peterson@neustar.biz

Cuellar, Morris, Mulligan, Peterson, Polk 26

Geopriv Requirements Mar 2003

Concord, CA 94520 http://www.neustar.biz/
USA

James M. Polk
Cisco Systems
2200 East President George Bush Turnpike
Richardson, Texas 75082 USA7 Email: jmpolk@cisco.com

13. Full Copyright Statement

Cuellar, Morris, Mulligan 23

Geopriv Requirements Jan 2003

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