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Network Working Group                                        D. von Hugo
Internet-Draft                                          Deutsche Telekom
Intended status: Standards Track                             B. Sarikaya
Expires: December 5, 2019                            Denpel Informatique
                                                              L. Iannone
                                                       Telecom ParisTech
                                                             A. Petrescu
                                                               CEA, LIST
                                                                  K. Sun
                                                     Soongsil University
                                                              U. Fattore
                                                            June 3, 2019

    Problem Statement for Secure End to End Privacy in IdLoc Systems


   Efficient and service aware flexible end-to-end routing in future
   communication networks is achieved by routing protocol approaches
   making use of Identifier Locator separation systems.  Since these
   systems require a correlation between identifiers and location which
   might allow tracking and misusage of individuals' identities and
   locations such operation demands for highly secure measures to
   preserve privacy of users and devices.  This document tries to
   identify and describe typical use cases and derive thereof a problem
   statement describing issues and challenges for application of privacy
   preserving Identifier-Locator split (PidLoc) approaches.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on December 5, 2019.

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Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions and Terminology . . . . . . . . . . . . . . . . .   3
   3.  Identifier Locator Separation Protocols . . . . . . . . . . .   4
     3.1.  ILNP  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  ILA . . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.3.  LISP  . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.4.  Privacy in IdLoc Protocols  . . . . . . . . . . . . . . .   5
   4.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . .   6
     4.1.  Industrial IoT  . . . . . . . . . . . . . . . . . . . . .   6
     4.2.  5G Use Case . . . . . . . . . . . . . . . . . . . . . . .   6
     4.3.  Cloud Use Case  . . . . . . . . . . . . . . . . . . . . .   7
     4.4.  Vehicular Networks  . . . . . . . . . . . . . . . . . . .   7
   5.  PIdLoc Issues and Challenges  . . . . . . . . . . . . . . . .   8
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   Forthcoming future communication systems which are currently under
   specification by various SDOs (Standards Development Organizations)
   try to achieve higher resource efficiency and flexibility as compared
   to currently deployed and operated networks.  Independent of specific
   access technologies, multiple applications shall be served with
   different levels of policy-driven mobility support and quality of
   service in terms of bandwidth, latency, error probability, etc.
   Current practice of IP address usage includes semantics as session
   identification as well as entity location and name resolution.  Many
   networking and information processing related topics as cloud

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   computing, software defined networking, network function
   virtualization, logical network slicing, and convergence of multiple
   heterogeneous access and transport technologies call for new
   approaches towards service specific and optimized packet routing.

   Promising proposals are Identifier Locator (Id-Loc) separation
   systems like Identifier Locator Addressing (ILA)
   [I-D.herbert-intarea-ila], Identifier-Locator Network Protocol (ILNP)
   [RFC6740], Locator/ID Separation Protocol (LISP)
   [I-D.ietf-lisp-rfc6830bis] [I-D.ietf-lisp-rfc6833bis], and others.

   Architectures and protocols for these approaches are already
   documented in detail and are under continuous evolution in different
   WGs.  This document on the other hand attempts to identify potential
   issues with respect to real-world deployment scenarios, which may
   demand for implementations of the above-mentionned Id-Loc systems.
   In particular, this document focuses on issues related to threats due
   to privacy violation of devices and their users, as well as location
   detection and movement tracking, where specific countermeasures may
   be needed.

   To provide a problem statement this draft documents common aspects
   and differences of several Id-Loc approaches from a high-level
   perspective and describes a set of use cases resulting in identified
   issues and challenges concerning privacy and security.  A set of
   requirements as outcome of a detailed analysis of these both generic
   and use cases specific questions will be provided in a companion

2.  Conventions and Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC 2119 [RFC2119].

   Identifier: An identifier is information allowing to unambiguously
   identify an entity or an entity group within a given scope.  An
   identifier is the equivalent of an End-point IDentifier (EID) in The
   Locator/ID Separation Protocol (LISP).  It may or may not be visible
   in communications.

   Locator: A locator is a routable network address.  It may be
   associated with an identifier and used for communication on the
   network layer according to identifier locator split principle.  A
   locator is the equivalent of a Routing Locator (RLOC) in LISP or an
   IP address in other cases.

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3.  Identifier Locator Separation Protocols

   Identifier represents a communication end-point of an entity and may
   not be routable.  Locator also represents a communication end-point,
   however, it is a routable network address.  Because entities
   identified by an Identifier can move the association between
   Identifiers and Locators may be ephemeral.  A database called a
   mapping system needs to be used for Identifier to Locator mapping.
   Identifiers are mapped to locators for reachability purposes.  A
   mapping system has to handle mobility by updating the identifier to
   locator mappings in the database.

   To start the communication, a device needs to know the identifier of
   the destination, hence it relies on a identifier lookup process to
   obtain the associated locator(s).  Note that both identifier and
   locator may be carried in clear in packet headers, depending on the
   specific technology used and the level of security/privacy enforced.

   Usage of identifiers readily available for public access raises
   privacy issues.  For public entities, it may be desirable to have
   their fully qualified domain names or host names available for public
   lookups by the clients, however, this is not the case in general for
   all identifiers, e.g. for individuals roaming in a mobile network.

3.1.  ILNP

   Identifier-Locator Network Protocol (ILNP) [RFC6740] is a host- based
   approach enabling mobility using mechanisms that are only deployed in
   end-systems and do not require any router changes.

3.2.  ILA

   Identifier-Locator Addressing (ILA) [I-D.herbert-intarea-ila] uses
   address transformation proposing to split an IPv6 address in 64-bit
   identifier (lower address bits) and locator (higher address bits)
   portions.  The locator part is determined dynamically from a mapping
   table that maintains associations between the location-independent
   identifiers and topologically significant locators.

   ILA is currently deployed in commercially available cloud systems
   such as Facebook and Google which are Layer 3 based.  Also A kernel
   implementation of ILA is available in Linux distribution.  ILA does
   not require any transport layer (UDP/TCP) changes.

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3.3.  LISP

   Locator/Id Separation Protocol (LISP) [I-D.ietf-lisp-rfc6830bis]
   [I-D.ietf-lisp-rfc6833bis] is based on a map-and-encap approach,
   which provides a level of indirection for routing and addressing
   performed at specific ingress/egress routers at the LISP domain
   boundaries.  Such border routers performing LISP encapsulation at the
   packet's source stub network are indicated as Ingress Tunnel Routers
   (ITRs), while border routers at the packet's destination stub network
   are called Egress Tunnel Routers (ETRs), all of them are indicated by
   the general term xTRs.  In order to obtain mappings used for
   encapsulation operation, xTRs query the mapping system in order to
   obtain all mappings related to a certain EID only when necessary
   (usually, but not exclusively, at the beginning of a new flow
   transmission).  The LISP control plane protocol
   [I-D.ietf-lisp-rfc6833bis] allows to support several different
   mapping systems (e.g., LISP+ALT [RFC6836] and LISP-DDT [RFC8111]).
   More than that, it can actually also be applied to various other data
   plane protocols.

3.4.  Privacy in IdLoc Protocols

   In all of the above protocols of ILNP, ILA and LISP, the identifiers
   are carried in packet headers in clear and therefore preserving
   identifier's privacy is needed.  Otherwise private information such
   as the location and content of the communication can be revealed.

   In case of ILNP, public DNS can be used to by the end nodes to access
   the destination identifier for a given Fully Qualified Domain Name
   (FQDN).  However the same node also gets the locator values raising
   serious privacy issues in the control plane.  As for the data plane,
   both source locator and identifier need to be privacy protected and
   techniques such as locator rewriting and ephemeral-use identifiers,
   respectively are suggested.

   In the control plane, ILA exhibits similar privacy issues if the ILA
   mapping system defining identifier locator mappings can publicly be
   accessed.  In ILA, privacy is addressed in the data plane by way of
   UE simultaneously using different addresses for different connections
   chosen from a block of addresses.

   In LISP mapping system, the lack of privacy support in the control
   plane for a given identifier value exists due to the use of DNS, as
   in ILNP.  In the data plane, privacy addressing by way of UE
   simultaneously using different addresses for different connections
   chosen from a block of addresses can be used as in ILA.

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4.  Use Cases

   The collection of use cases shall serve as starting point to identify
   different issues and challenges allowing for later derivation of
   requirements to future solutions providing privacy and security in
   generic Identifier Locator Split approaches.

4.1.  Industrial IoT

   Sensors and other connected things in the industry are usually not
   personal items (e.g. wearables) potentially revealing an individual's
   sensitive information.  Yet, industrial connected objects are
   business assets which should be detected/accessed only by authorised
   intra-company entities.  Since the huge amount of these things
   (massive IoT) as well as the typical energy and bandwidth constraints
   of battery-powered devices may pose a challenge to traditional
   routing and security measures, privacy enabled Id-Loc split
   approaches are proposed as a viable approach here,

   In Industrial IoT, there are very strong reasons to not share the ID/
   Locator binding with third parties, i.e. retain the privacy.  This
   can be achieved in a number of ways such as: using an ID/locator
   system but using some fixed anchor points a locator; injecting
   routing prefixes for the ID prefixes into the normal routing system
   and use proxy indirection; providing limited ID/Locator exposure.
   These are just examples, more approaches should be explored in order
   to find which one is the most suitable in the context of industrial

4.2.  5G Use Case

   Upcoming new truly universal communication via so-called 5G systems
   will demand for much more than (just) higher bandwidth and lower
   latency.  Integration of heterogeneous multiple access technologies
   (both wireless and wireline) controlled by a common converged core
   network and the evolution to service-based flexile functionalities
   instead of hard-coded network functions calls for new protocols both
   on control and user (data) plane.  While Id-Loc approach would serve
   well here, the challenge to provide a unique level of security and
   privacy even for a lightweight routing and forwarding mechanism -
   allowing for ease of deployment and migration from existing
   operational network architecture - remains to be solved.

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4.3.  Cloud Use Case

   The cloud, i.e. a set of distributed data centers for processing and
   storage connected via high speed transmission paths, is seen as
   logical location for content and also for virtualized network
   function instances and shall provide measures for easy re-location
   and migration of these instances deployed as e.g. containers or
   virtual machines.  Id-Loc split routing protocols are proposed for
   usage here as in ILA [I-D.herbert-intarea-ila] and LISP
   [I-D.ietf-lisp-rfc6830bis] [I-D.ietf-lisp-rfc6833bis] while the
   topology of the cloud components and logical correlations shall be
   invisible from outside.

   In a cloud, an upstream IP address does not necessarily belong to the
   actual service location, but a gateway or load balancer.  So, the
   locator or also ID reveal the location with the accuracy of a data
   center, not the function taking a service request.  This issue also
   manifests itself in today's LTE as PGWs are in a data center binding
   UEs' IP addresses which are from the network of the data center.

4.4.  Vehicular Networks

   In vehicular networks use cases (e.g. for a future C-ITS, i.e.
   Cooperative Intelligent Transport Systems) there are some problems
   related to privacy.  Cars are mandated to beacon CAM messages
   (cooperative awareness message - also denoted as basic service
   message, BSM) very frequently (more than 1 per second).  These
   messages contain identifiers such as MAC addresses.  They are unique
   and visible in the public oui.txt file.  They can be tracked.  But
   these are MAC addresses, not IP addresses.

   If, in the future, cars beacon Router Advertisements as well, then
   there is a risk in the source address of these RAs - the link local
   (LL) address.  They are usually formed out of the MAC address, even
   though recent RFC7217 [RFC7217] give suggestion of using a random ID
   in the IID (Interface Identifiers) (rather than the MAC address); the
   RFC stays silent about the prefix length; since the RFC7217 method
   covers also the LL addresses, and requires them to be RFC4291-like
   (64bit length), that random ID is still of fixed length (64).  Longer
   than 64 IIDs may benefit privacy, since crypto attacks on them would
   be harder.

   A variable length IID in link-local addresses may help create a
   flexible identifier-locator split thus increasing privacy.

   In addition C-ITS shall also allow to improve vehicular network based
   services as e.g. predict traffic congestion along the route and
   propose a re-direction towards alternative routes, or predict network

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   coverage along the foreseen path to adapt a critical service.  This
   on the other hand demands for knowledge of the actual route, i.e.
   tracking of the vehicle.  As was shown in [NYC_cab] even anonymizing
   sometimes does not prevent from privacy breaches.  ...

   Strong access control to ID/LOC mapping system(e.g. using longer and
   variable length of IID, crypto-ID, etc.) has some tradeoffs between
   enhancing privacy and increasing delay.  Furthermore, in the
   vehicular network, reducing delay is also very important issue
   because vehicle moves too fast to have enough time to configure.

   For V2V communication, using temporary identifier between two
   vehicles can be one solution to prevent privacy.  When we think of
   the example for V2V communication, most of their data includes
   current traffic condition, speed, or accident information which are
   not related to identify their unique device information.
   [I-D.ietf-lisp-eid-anonymity] can be one good solution to provide
   anonymity.  In [I-D.ietf-ipwave-vehicular-networking], they suggest
   MAC address pseudonym in which MAC address is changed periodically.

5.  PIdLoc Issues and Challenges

   This section concludes on both common and specific issues and
   challenges in PIdLoc to allow for derivation of requirements to
   potential solutions serving for a gap analysis to be documented in
   upcoming drafts, e.g.  (I-D.xyz-pidloc-reqs).

6.  IANA Considerations


7.  Security Considerations


8.  Acknowledgements

9.  References

              Herbert, T. and P. Lapukhov, "Identifier-locator
              addressing for IPv6", draft-herbert-intarea-ila-01 (work
              in progress), March 2018.

              Touch, J. and M. Townsley, "IP Tunnels in the Internet
              Architecture", draft-ietf-intarea-tunnels-09 (work in
              progress), July 2018.

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              Jeong, J., "IP Wireless Access in Vehicular Environments
              (IPWAVE): Problem Statement and Use Cases", draft-ietf-
              ipwave-vehicular-networking-09 (work in progress), May

              Farinacci, D., Pillay-Esnault, P., and W. Haddad, "LISP
              EID Anonymity", draft-ietf-lisp-eid-anonymity-06 (work in
              progress), April 2019.

              Farinacci, D., Fuller, V., Meyer, D., Lewis, D., and A.
              Cabellos-Aparicio, "The Locator/ID Separation Protocol
              (LISP)", draft-ietf-lisp-rfc6830bis-26 (work in progress),
              November 2018.

              Fuller, V., Farinacci, D., and A. Cabellos-Aparicio,
              "Locator/ID Separation Protocol (LISP) Control-Plane",
              draft-ietf-lisp-rfc6833bis-24 (work in progress), February

              Maino, F., Ermagan, V., Cabellos-Aparicio, A., and D.
              Saucez, "LISP-Security (LISP-SEC)", draft-ietf-lisp-sec-18
              (work in progress), June 2019.

              Nordmark, E., "Privacy issues in ID/locator separation
              systems", draft-nordmark-id-loc-privacy-00 (work in
              progress), July 2018.

   [NYC_cab]  Douriez, et al., M., "Anonymizing NYC Taxi Data: Does It
              Matter?", Proc. of IEEE Intl. Conf. on Data Science and
              Advanced Analytics (DSAA'16) , pp. 140-148, 2016.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,

   [RFC6740]  Atkinson, RJ. and SN. Bhatti, "Identifier-Locator Network
              Protocol (ILNP) Architectural Description", RFC 6740,
              DOI 10.17487/RFC6740, November 2012,

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   [RFC6836]  Fuller, V., Farinacci, D., Meyer, D., and D. Lewis,
              "Locator/ID Separation Protocol Alternative Logical
              Topology (LISP+ALT)", RFC 6836, DOI 10.17487/RFC6836,
              January 2013, <https://www.rfc-editor.org/info/rfc6836>.

   [RFC7217]  Gont, F., "A Method for Generating Semantically Opaque
              Interface Identifiers with IPv6 Stateless Address
              Autoconfiguration (SLAAC)", RFC 7217,
              DOI 10.17487/RFC7217, April 2014,

   [RFC8111]  Fuller, V., Lewis, D., Ermagan, V., Jain, A., and A.
              Smirnov, "Locator/ID Separation Protocol Delegated
              Database Tree (LISP-DDT)", RFC 8111, DOI 10.17487/RFC8111,
              May 2017, <https://www.rfc-editor.org/info/rfc8111>.

Authors' Addresses

   Dirk von Hugo
   Deutsche Telekom
   Deutsche-Telekom-Allee 7
   D-64295 Darmstadt

   Email: Dirk.von-Hugo@telekom.de

   Behcet Sarikaya
   Denpel Informatique

   Email: sarikaya@ieee.org

   Luigi Iannone
   Telecom ParisTech

   Email: ggx@gigix.net

   Alex Petrescu

   Email: alexandre.petrescu@gmail.com

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   Kyoungjae Sun
   Soongsil University

   Email: gomjae@dcn.ssu.ac.kr

   Umberto Fattore

   Email: Umberto.Fattore@neclab.eu

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