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Versions: 00 draft-ietf-6man-ipv6-address-generation-privacy

Network Working Group                                          A. Cooper
Internet-Draft                                                       CDT
Intended status: Informational                                   F. Gont
Expires: January 16, 2014                            Huawei Technologies
                                                               D. Thaler
                                                               Microsoft
                                                           July 15, 2013


     Privacy Considerations for IPv6 Address Generation Mechanisms
        draft-cooper-6man-ipv6-address-generation-privacy-00.txt

Abstract

   This document discusses privacy and security considerations for
   several IPv6 address generation mechanisms, both standardized and
   non-standardized.  It evaluates how different mechanisms mitigate
   different threats and the trade-offs that implementors, developers,
   and users face in choosing different addresses or address generation
   mechanisms.

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

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

   This Internet-Draft will expire on January 16, 2014.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect



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   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Weaknesses in IEEE-identifier-based IIDs  . . . . . . . . . .   4
     3.1.  Correlation of activities over time . . . . . . . . . . .   4
     3.2.  Location tracking . . . . . . . . . . . . . . . . . . . .   5
     3.3.  Address scanning  . . . . . . . . . . . . . . . . . . . .   6
     3.4.  Device-specific vulnerability exploitation  . . . . . . .   6
   4.  Privacy and security properties of address generation
       mechanisms  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     4.1.  Single-address scenarios  . . . . . . . . . . . . . . . .   7
       4.1.1.  Static, manually configured address only  . . . . . .   8
       4.1.2.  Cryptographically generated address only  . . . . . .   8
       4.1.3.  Temporary address only  . . . . . . . . . . . . . . .   8
       4.1.4.  Persistent random address only  . . . . . . . . . . .   8
       4.1.5.  Random-per-network address only . . . . . . . . . . .   9
       4.1.6.  DHCPv6 address only . . . . . . . . . . . . . . . . .   9
     4.2.  Multiple-address scenarios  . . . . . . . . . . . . . . .   9
       4.2.1.  Temporary addresses and IEEE-identifier-based address  10
       4.2.2.  Temporary addresses and persistent random address . .  11
       4.2.3.  Temporary addresses and random-per-network addresses   11
   5.  Other Privacy Issues  . . . . . . . . . . . . . . . . . . . .  11
   6.  Miscellaneous Issues with IPv6 addressing . . . . . . . . . .  12
     6.1.  Network Operation . . . . . . . . . . . . . . . . . . . .  12
     6.2.  Compliance  . . . . . . . . . . . . . . . . . . . . . . .  12
     6.3.  Intellectual Property Rights (IPRs) . . . . . . . . . . .  12
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  13
   10. Informative References  . . . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction












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   IPv6 was designed to improve upon IPv4 in many respects, and
   mechanisms for address assignment were one such area for improvement.
   In addition to static address assignment and DHCP, stateless
   autoconfiguration was developed as a less intensive, fate-shared
   means of performing address assignment.  With stateless
   autoconfiguration, routers advertise on-link prefixes and hosts
   generate their own interface identifiers (IIDs) to complete their
   addresses.  Over the years, many interface identifier generation
   techniques have been defined, both standardized and non-standardized:

   o  Manual configuration

      *  IPv4 address

      *  Service port

      *  Wordy

      *  Low-byte

   o  Stateless Address Auto-Cofiguration (SLAAC)

      *  IEEE 802 48-bit MAC or IEEE EUI-64 identifier
         [RFC1972][RFC2464]

      *  Cryptographically generated [RFC3972]

      *  Persistent random [Microsoft]

      *  Temporary (also known as "privacy addresses") [RFC4941]

      *  Random-per-network (also known as "stable privacy addresses")
         [I-D.ietf-6man-stable-privacy-addresses]

   o  DHCPv6-based [RFC3315]

   o  Specified by transition/co-existence technologies

      *  IPv4 address and port [RFC4380]

   Deriving the IID from a globally unique IEEE identifier [RFC2462] was
   one of the earliest mechanisms developed.  A number of privacy and
   security issues related to the interface IDs derived from IEEE
   identifiers were discovered after their standardization, and many of
   the mechanisms developed later aimed to mitigate some or all of these
   weaknesses.  This document identifies four types of threats against
   IEEE-identifier-based IIDs, and discusses how other existing
   techniques for generating IIDs do or do not mitigate those threats.



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2.  Terminology

   This section clarifies the terminology used throughout this document.

   Stable address:
      An address that does not vary over time within the same network.
      Note that [RFC4941] refers to these as "public" addresses, but
      "stable" is used here for reasons explained in Section 4.2.

   Temporary address:
      An address that varies over time within the same network.

   Public address:
      An address that has been published on some sort of directory
      service, such as the DNS [RFC1034].

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   [RFC2119].  These words take their normative meanings only when they
   are presented in ALL UPPERCASE.

3.  Weaknesses in IEEE-identifier-based IIDs

   There are a number of privacy and security implications that exist
   for hosts that use IEEE-identifier-based IIDs.  This section
   discusses four generic attack types: correlation of activities over
   time, location tracking, device-specific vulnerability exploitation,
   and address scanning.  The first three of these rely on the attacker
   first gaining knowledge of the target host's IID.  This can be
   achieved by a number of different attackers: the operator of a server
   to which the host connects, such as a web server or a peer-to-peer
   server; an entity that connects to the same network as the target
   (such as a conference network or any public network); or an entity
   that is on-path to the destinations with which the host communicates,
   such as a network operator.

3.1.  Correlation of activities over time

   As with other identifiers, an IPv6 address can be used to correlate
   the activities of a host for at least as long as the lifetime of the
   address.  The correlation made possible by IEEE-identifier-based IIDs
   is of particular concern because MAC addresses are much more
   permanent than, say, DHCP leases.  MAC addresses tend to last roughly
   the lifetime of a device's network interface, allowing correlation on
   the order of years, compared to days for DHCP.

   As [RFC4941] explains,



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      "[t]he use of a non-changing interface identifier to form
      addresses is a specific instance of the more general case where a
      constant identifier is reused over an extended period of time and
      in multiple independent activities.  Anytime the same identifier
      is used in multiple contexts, it becomes possible for that
      identifier to be used to correlate seemingly unrelated activity.
      ... The use of a constant identifier within an address is of
      special concern because addresses are a fundamental requirement of
      communication and cannot easily be hidden from eavesdroppers and
      other parties.  Even when higher layers encrypt their payloads,
      addresses in packet headers appear in the clear."

   IP addresses are just one example of information that can be used to
   correlate activities over time.  DNS names, cookies [RFC6265],
   browser fingerprints [Panopticlick], and application-layer usernames
   can all be used to link a host's activities together.  Although IEEE-
   identifier-based IIDs are likely to last at least as long or longer
   than these other identifiers, IIDs generated in other ways may have
   shorter or longer lifetimes than these identifiers depending on how
   they are generated.  Therefore, the extent to which a host's
   activities can be correlated depends on whether the host uses
   multiple identifiers together and the lifetimes of all of those
   identifiers.  Frequently refreshing an IPv6 address may not mitigate
   correlation if an attacker has access to other longer lived
   identifiers for a particular host.  This is an important caveat to
   keep in mind throughout the discussion of correlation in this
   document.  For further discussion of correlation, see Section 5.2.1
   of [I-D.iab-privacy-considerations].

3.2.  Location tracking

   Because the IPv6 address structure is divided between a topological
   portion and an interface identifier portion, an interface identifier
   that remains constant when a host connects to different networks (as
   an IEEE-identifier-based IID does) provides a way for observers to
   track the movements of that host.  In a passive attack on a mobile
   host, a server that receives connections from the same host over time
   would be able to determine the host's movements as its prefix
   changes.












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   Active attacks are also possible.  An attacker that first learns the
   host's interface identifier by being connected to the same network
   segment, running a server that the host connects to, or being on-path
   to the host's communications could subsequently probe other networks
   for the presence of the same interface identifier by sending a probe
   packet (ICMPv6 Echo Request, or any other probe packet).  Even if the
   host does not respond, the first hop router will usually respond with
   an ICMP Address Unreachable when the host is not present, and be
   silent when the host is present.

3.3.  Address scanning

   The structure of IEEE-based identifiers used for address generation
   can be leveraged by an attacker to reduce the target search space
   [I-D.ietf-opsec-ipv6-host-scanning].  The 24-bit Organizationally
   Unique Identifier (OUI) of MAC addresses, together with the fixed
   value (0xff, 0xfe) used to form a Modified EUI-64 Interface
   Identifier, greatly help to reduce the search space, making it easier
   for an attacker to scan for individual addresses using widely-known
   popular OUIs.

3.4.  Device-specific vulnerability exploitation

   IPv6 addresses that embed IEEE identifiers leak information about the
   device (Network Interface Card vendor, or even Operating System and/
   or software type), which could be leveraged by an attacker with
   knowledge of device/software-specific vulnerabilities to quickly find
   possible targets.  Attackers can exploit vulnerabilities in hosts
   whose IIDs they have previously obtained, or scan an address space to
   find potential targets.

4.  Privacy and security properties of address generation mechanisms

   Analysis of the extent to which a particular host is protected
   against the threats described in Section 3 depends on how each of a
   host's IIDs is generated and used.  In some scenarios, a host
   configures a single global address and uses it for all
   communications.  In other scenarios, a host configures multiple
   addresses using different mechanisms and may use any or all of them.
   This section compares the privacy and security properties of a
   variety of IID generation/use scenarios.  The scenarios are grouped
   according to whether one or more addresses are configured.  The table
   below provides a summary of the analysis.

   +--------------+-------------+------------+------------+------------+
   | Mechanism(s) | Correlation | Location   | Address    | Device     |
   |              |             | tracking   | scanning   | exploits   |
   +--------------+-------------+------------+------------+------------+



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   | Static       | For address | For        | NP         | Depends on |
   | manual only  | lifetime    | address    |            | generation |
   |              |             | lifetime   |            | mechanism  |
   |              |             |            |            |            |
   | CGA only     | Within      | NP         | NP         | NP         |
   |              | single      |            |            |            |
   |              | network     |            |            |            |
   |              |             |            |            |            |
   | Temporary    | NP          | NP         | NP         | NP         |
   | only         |             |            |            |            |
   |              |             |            |            |            |
   | Persistent   | For address | For        | NP         | NP         |
   | random only  | lifetime    | address    |            |            |
   |              |             | lifetime   |            |            |
   |              |             |            |            |            |
   | Random-per-  | Within      | NP         | NP         | NP         |
   | network only | single      |            |            |            |
   |              | network     |            |            |            |
   |              |             |            |            |            |
   | Temporary    | When IEEE-  | Possible   | Possible   | Possible   |
   | and IEEE-    | based is in |            |            |            |
   | based        | use, or for |            |            |            |
   |              | temp        |            |            |            |
   |              | address     |            |            |            |
   |              | lifetime    |            |            |            |
   |              |             |            |            |            |
   | Temporary    | When random | Possible   | Possible   | Possible   |
   | and          | is in use,  |            |            |            |
   | persistent   | or for temp |            |            |            |
   | random       | address     |            |            |            |
   |              | lifetime    |            |            |            |
   |              |             |            |            |            |
   | Temporary    | Within      | NP         | NP         | NP         |
   | and random-  | single      |            |            |            |
   | per-network  | network, or |            |            |            |
   |              | for temp    |            |            |            |
   |              | address     |            |            |            |
   |              | lifetime    |            |            |            |
   +--------------+-------------+------------+------------+------------+

                         Legend: NP = Not possible

    Table 1: Privacy and security properties of IPv6 address generation
                                mechanisms

4.1.  Single-address scenarios





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4.1.1.  Static, manually configured address only

   Because static, manually configured addresesses are persistent, both
   correlation and location tracking are possible for the life of the
   address.

   The extent to which location tracking can be successfully performed
   depends, to a some extent, on the uniqueness of the employed
   Intarface ID.  For example, one would expect "low byte" Interface IDs
   to be more widely reused than, for example, Interface IDs where the
   whole 64-bits follow some pattern that is unique to a specific
   organization.  Widely reused Interface IDs will typically lead to
   false positives when performing location tracking.

   Because they do not embed OUIs, manually configured addresses are not
   vulnerable to device-specific exploitation.  Whether they are
   vulnerable to address scanning depends on the specifics of how they
   are generated.

4.1.2.  Cryptographically generated address only

   Cryptographically generated addresses (CGAs) [RFC3972] bind a hash of
   the host's public key to an IPv6 address in the SEcure Neighbor
   Discovery (SEND) [RFC3971] protocol.  CGAs are uniquely generated for
   each subnet prefix, which means that correlation is possible within a
   single network only.  A host that stays connected to the same network
   could therefore be tracked at length, whereas a mobile host's
   activities could only be correlated for the duration of each network
   connection.  Location tracking is not possible with CGAs.  CGAs also
   do not allow device-specific exploitation or address scanning
   attacks.

4.1.3.  Temporary address only

   A host that uses only a temporary address mitigates all four threats.
   Its activities may only be correlated for the lifetime a single
   address.

4.1.4.  Persistent random address only

   Although a mechanism to generate a static, random IID has not been
   standardized, it has been in wide use for many years on at least one
   platform (Windows).  Windows uses the [RFC4941] random generation
   mechanism in lieu of generating an IEEE-identifier-based IID.  This
   mitigates the device-specific exploitation and address scanning
   attacks, but still allows correlation and location tracking because
   the address is persistent across networks and time.




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4.1.5.  Random-per-network address only

   [I-D.ietf-6man-stable-privacy-addresses] specifies a mechanism that
   generates a unique random IID for each network.  A host that stays
   connected to the same network could therefore be tracked at length,
   whereas a mobile host's activities could only be correlated for the
   duration of each network connection.  Location tracking is not
   possible with these addresses.  They also do not allow device-
   specific exploitation or address scanning attacks.

4.1.6.  DHCPv6 address only

   TBD

4.2.  Multiple-address scenarios

   [RFC3041] (later obsoleted by [RFC4941]) sought to address some of
   the problems described in Section 3 by defining "temporary addresses"
   (commonly referred to as "privacy addresses") for outbound
   connections.  Temporary addresses are meant to supplement the other
   IIDs that a device might use, not to replace them.  They are randomly
   generated and change daily by default.  The idea was for temporary
   addresses to be used for outgoing connections (e.g. web browsing)
   while maintaining the ability to use a stable address when more
   address stability is desired (e.g., in DNS advertisements).

   [RFC3484] originally specified that stable addresses be used for
   outbound connections unless an application explicitly prefers
   temporary addresses.  The default preference for stable addresses was
   established to avoid applications potentially failing due to the
   short lifetime of temporary addresses or the possibility of a reverse
   look-up failure or error.  However, [RFC3484] allowed that
   "implementations for which privacy considerations outweigh these
   application compatibility concerns MAY reverse the sense of this
   rule" and instead prefer by default temporary addresses rather than
   stable addresses.  Indeed most implementations (notably including
   Windows) chose to default to temporary addresses for outbound
   connections since privacy was considered more important (and few
   applications supported IPv6 at the time, so application compatibility
   concerns were minimal).  [RFC6724] then obsoleted [RFC3484] and
   changed the default to match what implementations actually did.

   The envisioned relationship in [RFC3484] between stability of an
   address and its use in "public" can be misleading when conducting
   privacy analysis.  The stability of an address and the extent to
   which it is linkable to some other public identifier are independent
   of one another.  For example, there is nothing that prevents a host
   from publishing a temporary address in a public place, such as the



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   DNS.  Publishing both a stable address and a temporary address in the
   DNS or elsewhere where they can be linked together by a public
   identifier allows the host's activities when using either address to
   be correlated together.

   Moreover, because temporary addresses were designed to supplement
   other addresses generated by a host, the host may still configure a
   more stable address even if it only ever intentionally uses temporary
   addresses (as source addresses) for communication to off-link
   destinations.  An attacker can probe for the stable address even if
   it is never used as such a source address or advertised (e.g., in DNS
   or SIP) outside the link.

   The scenarios in this section describe the privacy and security
   properties in cases where a host configures both a temporary address
   and an address generated via another mechanism.  The analysis
   distinguishes between cases when both addresses are used as source
   addresses or are advertised off-link and cases where only the
   temporary address is used in those manners.

   [TO DO: Add in Temporary + manual, Temporary + DHCP, Temporary +
   other link-layer-derived, Temporary + CGA, and perhaps re-arrange
   this section to avoid repetition.]

4.2.1.  Temporary addresses and IEEE-identifier-based address

   By using an IEEE-identifier-based IID and temporary addresses, a host
   can be vulnerable to the same attacks as if temporary addresses were
   not in use, although the viability of some of them depends on how the
   host uses each address.  An attacker can correlate all of the host's
   activities for which it uses its IEEE-identifier-based IID.  Once an
   attacker has obtained the IEEE-identifier-based IID, location
   tracking becomes possible on other networks even if the host only
   makes use of temporary addresses on those other networks; the
   attacker can actively probe the other networks for the presence of
   the IEEE-identifier-based IID.  Device-specific vulnerabilities can
   still be exploited.  Address scanning is also still possible because
   the IEEE-identifier-based address can be probed.

   A host that configures but does not use an IEEE-identifier-based IID
   is vulnerable to address scanning because the address can be probed
   even if the IEEE-identifier-based address is otherwise never used.
   Once an attacker has received such a response, it can exploit device-
   specific vulnerabilities or probe other networks over time to track
   the location of the host.  Correlation over time, however, is
   significantly mitigated, since the temporary addresses that the host
   routinely uses on the network refresh often.




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4.2.2.  Temporary addresses and persistent random address

   Using a persistent, random address as a stable address for server-
   like connections together with temporary addresses for outbound
   connections presents some improvements over the previous scenario.
   The address scanning and device-specific exploitation attacks are no
   longer possible because the OUI is no longer embedded in any of the
   host's addresses.  However, correlation of some activities across
   time and location tracking are both still possible because the random
   IID is persistent.  As in Section 4.2.1, once an attacker has
   obtained the host's random IID, location tracking is possible on any
   network by probing for that IID, even if the host only uses temporary
   addresses on those networks.

   A host that configures but does not use a persistent random address
   mitigates all four threats.  Correlation is only possible for the
   lifetime of a temporary address.  The persistent random address
   cannot be easily discovered in an address scan (although it is
   available to an on-link adversary), which prevents an attacker from
   using it for location tracking or device-specific exploitation.

4.2.3.  Temporary addresses and random-per-network addresses

   When used together with temporary addresses, the random-per-network
   mechanism [I-D.ietf-6man-stable-privacy-addresses] improves upon the
   previous scenario by limiting the potential for correlation to the
   lifetime of the random-per-network address (which may still be
   lengthy for hosts that are not mobile) and eliminating the
   possibility for location tracking (since a different IID is generated
   for each subnet prefix).

   As in the previous scenario, a host that configures but does not use
   a random-per-network address mitigates all four threats.

5.  Other Privacy Issues

   Since IPv6 subnets have unique prefixes, they reveal some information
   about the location of the subnet, just as IPv4 addresses do.  Hiding
   this information is one motivation for usng NAT in IPv6 (see RFC 5902
   section 2.4).











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   Teredo [RFC4380] specifies a means to generate an IPv6 address from
   the underlying IPv4 address and port, leaving many other bits set to
   zero.  This makes it relatively easy for an attacker to scan for IPv6
   addresses by guessing the Teredo client's IPv4 address and port
   (which for many NATs is not randomized).  For this reason, popular
   implementations (e.g., Windows), began deviating from the standard by
   including 12 random bits in place of zero bits.  This modification
   was later standardized in [RFC5991].

6.  Miscellaneous Issues with IPv6 addressing

6.1.  Network Operation

   It is generally agreed that IPv6 addresses that vary over time in a
   specific network tend to increase the complexity of event logging,
   trouble-shooting, enforcement of access controls and quality of
   service, etc.  As a result, some organizations disable the use of
   temporary addresses [RFC4941] even at the expense of reduced privacy
   [Broersma].

6.2.  Compliance

   Major IPv6 compliance testing suites required (and still require)
   implementations to support MAC-derived suffixes in order to be
   approved as compliant.  Implementations that fail to support MAC-
   derived suffixes are therefore largely not eligible to receive the
   benefits of compliance certification (e.g., use of the IPv6 logo,
   eligibility for government contracts, etc.).  This document
   recommends that these be relaxed to allow other forms of address
   generation that are more amenable to privacy.

6.3.  Intellectual Property Rights (IPRs)

   Some IPv6 addressing techniques might be covered by Intellectual
   Property rights, which might limit their implementation in different
   Operating Systems.  [CGA-IPR] and [KAME-CGA] discuss the IPRs on
   CGAs.

7.  Security Considerations

   This whole document concerns the privacy and security properties of
   different IPv6 address generation mechanisms.









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8.  IANA Considerations

   This document does not require actions by IANA.

9.  Acknowledgements

   The authors would like to thank Bernard Aboba and Rich Draves.

10.  Informative References

   [Broersma]
              Broersma, R., "IPv6 Everywhere: Living with a Fully
              IPv6-enabled environment", Australian IPv6 Summit 2010,
              Melbourne, VIC Australia, October 2010, October 2010,
              <http://www.ipv6.org.au/10ipv6summit/talks/
              Ron_Broersma.pdf>.

   [CGA-IPR]  IETF, "Intellectual Property Rights on RFC 3972", 2005.

   [I-D.iab-privacy-considerations]
              Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
              Morris, J., Hansen, M., and R. Smith, "Privacy
              Considerations for Internet Protocols", draft-iab-privacy-
              considerations-03 (work in progress), July 2012.

   [I-D.ietf-6man-stable-privacy-addresses]
              Gont, F., "A method for Generating Stable Privacy-Enhanced
              Addresses with IPv6 Stateless Address Autoconfiguration
              (SLAAC)", draft-ietf-6man-stable-privacy-addresses-10
              (work in progress), June 2013.

   [I-D.ietf-opsec-ipv6-host-scanning]
              Gont, F. and T. Chown, "Network Reconnaissance in IPv6
              Networks", draft-ietf-opsec-ipv6-host-scanning-01 (work in
              progress), April 2013.

   [KAME-CGA]
              KAME, "The KAME IPR policy and concerns of some
              technologies which have IPR claims", 2005.

   [Microsoft]
              Microsoft, "IPv6 interface identifiers", 2013.

   [Panopticlick]
              Electronic Frontier Foundation, "Panopticlick", 2011.

   [RFC1034]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, RFC 1034, November 1987.



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Internet-Draft       IPv6 Address Generation Privacy           July 2013


   [RFC1972]  Crawford, M., "A Method for the Transmission of IPv6
              Packets over Ethernet Networks", RFC 1972, August 1996.

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

   [RFC2462]  Thomson, S. and T. Narten, "IPv6 Stateless Address
              Autoconfiguration", RFC 2462, December 1998.

   [RFC2464]  Crawford, M., "Transmission of IPv6 Packets over Ethernet
              Networks", RFC 2464, December 1998.

   [RFC3041]  Narten, T. and R. Draves, "Privacy Extensions for
              Stateless Address Autoconfiguration in IPv6", RFC 3041,
              January 2001.

   [RFC3315]  Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
              and M. Carney, "Dynamic Host Configuration Protocol for
              IPv6 (DHCPv6)", RFC 3315, July 2003.

   [RFC3484]  Draves, R., "Default Address Selection for Internet
              Protocol version 6 (IPv6)", RFC 3484, February 2003.

   [RFC3971]  Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
              Neighbor Discovery (SEND)", RFC 3971, March 2005.

   [RFC3972]  Aura, T., "Cryptographically Generated Addresses (CGA)",
              RFC 3972, March 2005.

   [RFC4380]  Huitema, C., "Teredo: Tunneling IPv6 over UDP through
              Network Address Translations (NATs)", RFC 4380, February
              2006.

   [RFC4941]  Narten, T., Draves, R., and S. Krishnan, "Privacy
              Extensions for Stateless Address Autoconfiguration in
              IPv6", RFC 4941, September 2007.

   [RFC5991]  Thaler, D., Krishnan, S., and J. Hoagland, "Teredo
              Security Updates", RFC 5991, September 2010.

   [RFC6265]  Barth, A., "HTTP State Management Mechanism", RFC 6265,
              April 2011.

   [RFC6724]  Thaler, D., Draves, R., Matsumoto, A., and T. Chown,
              "Default Address Selection for Internet Protocol Version 6
              (IPv6)", RFC 6724, September 2012.





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Internet-Draft       IPv6 Address Generation Privacy           July 2013


Authors' Addresses

   Alissa Cooper
   CDT
   1634 Eye St. NW, Suite 1100
   Washington, DC  20006
   US

   Phone: +1-202-637-9800
   Email: acooper@cdt.org
   URI:   http://www.cdt.org/


   Fernando Gont
   Huawei Technologies
   Evaristo Carriego 2644
   Haedo, Provincia de Buenos Aires  1706
   Argentina

   Phone: +54 11 4650 8472
   Email: fgont@si6networks.com
   URI:   http://www.si6networks.com


   Dave Thaler
   Microsoft
   Microsoft Corporation
   One Microsoft Way
   Redmond, WA  98052

   Phone: +1 425 703 8835
   Email: dthaler@microsoft.com



















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