Network Working Group                                        P. Nikander
Request for Comments: 5205                  Ericsson Research NomadicLab
Category: Experimental                                       J. Laganier
                                                       DoCoMo Euro-Labs
                                                             April 2008


   Host Identity Protocol (HIP) Domain Name System (DNS) Extension

Status of This Memo

  This memo defines an Experimental Protocol for the Internet
  community.  It does not specify an Internet standard of any kind.
  Discussion and suggestions for improvement are requested.
  Distribution of this memo is unlimited.

Abstract

  This document specifies a new resource record (RR) for the Domain
  Name System (DNS), and how to use it with the Host Identity Protocol
  (HIP).  This RR allows a HIP node to store in the DNS its Host
  Identity (HI, the public component of the node public-private key
  pair), Host Identity Tag (HIT, a truncated hash of its public key),
  and the Domain Names of its rendezvous servers (RVSs).



























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Table of Contents

  1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
  2.  Conventions Used in This Document  . . . . . . . . . . . . . .  3
  3.  Usage Scenarios  . . . . . . . . . . . . . . . . . . . . . . .  4
    3.1.  Simple Static Singly Homed End-Host  . . . . . . . . . . .  5
    3.2.  Mobile end-host  . . . . . . . . . . . . . . . . . . . . .  6
  4.  Overview of Using the DNS with HIP . . . . . . . . . . . . . .  8
    4.1.  Storing HI, HIT, and RVS in the DNS  . . . . . . . . . . .  8
    4.2.  Initiating Connections Based on DNS Names  . . . . . . . .  8
  5.  HIP RR Storage Format  . . . . . . . . . . . . . . . . . . . .  9
    5.1.  HIT Length Format  . . . . . . . . . . . . . . . . . . . .  9
    5.2.  PK Algorithm Format  . . . . . . . . . . . . . . . . . . .  9
    5.3.  PK Length Format . . . . . . . . . . . . . . . . . . . . . 10
    5.4.  HIT Format . . . . . . . . . . . . . . . . . . . . . . . . 10
    5.5.  Public Key Format  . . . . . . . . . . . . . . . . . . . . 10
    5.6.  Rendezvous Servers Format  . . . . . . . . . . . . . . . . 10
  6.  HIP RR Presentation Format . . . . . . . . . . . . . . . . . . 10
  7.  Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
  8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 12
    8.1.  Attacker Tampering with an Insecure HIP RR . . . . . . . . 12
    8.2.  Hash and HITs Collisions . . . . . . . . . . . . . . . . . 13
    8.3.  DNSSEC . . . . . . . . . . . . . . . . . . . . . . . . . . 13
  9.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 13
  10. Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 14
  11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
    11.1. Normative references . . . . . . . . . . . . . . . . . . . 14
    11.2. Informative references . . . . . . . . . . . . . . . . . . 15























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1.  Introduction

  This document specifies a new resource record (RR) for the Domain
  Name System (DNS) [RFC1034], and how to use it with the Host Identity
  Protocol (HIP) [RFC5201].  This RR allows a HIP node to store in the
  DNS its Host Identity (HI, the public component of the node public-
  private key pair), Host Identity Tag (HIT, a truncated hash of its
  HI), and the Domain Names of its rendezvous servers (RVSs) [RFC5204].

  Currently, most of the Internet applications that need to communicate
  with a remote host first translate a domain name (often obtained via
  user input) into one or more IP address(es).  This step occurs prior
  to communication with the remote host, and relies on a DNS lookup.

  With HIP, IP addresses are intended to be used mostly for on-the-wire
  communication between end hosts, while most Upper Layer Protocols
  (ULP) and applications use HIs or HITs instead (ICMP might be an
  example of an ULP not using them).  Consequently, we need a means to
  translate a domain name into an HI.  Using the DNS for this
  translation is pretty straightforward: We define a new HIP resource
  record.  Upon query by an application or ULP for a name to IP address
  lookup, the resolver would then additionally perform a name to HI
  lookup, and use it to construct the resulting HI to IP address
  mapping (which is internal to the HIP layer).  The HIP layer uses the
  HI to IP address mapping to translate HIs and HITs into IP addresses
  and vice versa.

  The HIP Rendezvous Extension [RFC5204] allows a HIP node to be
  reached via the IP address(es) of a third party, the node's
  rendezvous server (RVS).  An Initiator willing to establish a HIP
  association with a Responder served by an RVS would typically
  initiate a HIP exchange by sending an I1 towards the RVS IP address
  rather than towards the Responder IP address.  Consequently, we need
  a means to find the name of a rendezvous server for a given host
  name.

  This document introduces the new HIP DNS resource record to store the
  Rendezvous Server (RVS), Host Identity (HI), and Host Identity Tag
  (HIT) information.

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 RFC 2119 [RFC2119].






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3.  Usage Scenarios

  In this section, we briefly introduce a number of usage scenarios
  where the DNS is useful with the Host Identity Protocol.

  With HIP, most applications and ULPs are unaware of the IP addresses
  used to carry packets on the wire.  Consequently, a HIP node could
  take advantage of having multiple IP addresses for fail-over,
  redundancy, mobility, or renumbering, in a manner that is transparent
  to most ULPs and applications (because they are bound to HIs; hence,
  they are agnostic to these IP address changes).

  In these situations, for a node to be reachable by reference to its
  Fully Qualified Domain Name (FQDN), the following information should
  be stored in the DNS:

  o  A set of IP address(es) via A [RFC1035] and AAAA [RFC3596] RR sets
     (RRSets [RFC2181]).

  o  A Host Identity (HI), Host Identity Tag (HIT), and possibly a set
     of rendezvous servers (RVS) through HIP RRs.

  When a HIP node wants to initiate communication with another HIP
  node, it first needs to perform a HIP base exchange to set up a HIP
  association towards its peer.  Although such an exchange can be
  initiated opportunistically, i.e., without prior knowledge of the
  Responder's HI, by doing so both nodes knowingly risk man-in-the-
  middle attacks on the HIP exchange.  To prevent these attacks, it is
  recommended that the Initiator first obtain the HI of the Responder,
  and then initiate the exchange.  This can be done, for example,
  through manual configuration or DNS lookups.  Hence, a new HIP RR is
  introduced.

  When a HIP node is frequently changing its IP address(es), the
  natural DNS latency for propagating changes may prevent it from
  publishing its new IP address(es) in the DNS.  For solving this
  problem, the HIP Architecture [RFC4423] introduces rendezvous servers
  (RVSs) [RFC5204].  A HIP host uses a rendezvous server as a
  rendezvous point to maintain reachability with possible HIP
  initiators while moving [RFC5206].  Such a HIP node would publish in
  the DNS its RVS domain name(s) in a HIP RR, while keeping its RVS up-
  to-date with its current set of IP addresses.

  When a HIP node wants to initiate a HIP exchange with a Responder, it
  will perform a number of DNS lookups.  Depending on the type of
  implementation, the order in which those lookups will be issued may
  vary.  For instance, implementations using HIT in APIs may typically
  first query for HIP resource records at the Responder FQDN, while



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  those using an IP address in APIs may typically first query for A
  and/or AAAA resource records.

  In the following, we assume that the Initiator first queries for HIP
  resource records at the Responder FQDN.

  If the query for the HIP type was responded to with a DNS answer with
  RCODE=3 (Name Error), then the Responder's information is not present
  in the DNS and further queries for the same owner name SHOULD NOT be
  made.

  In case the query for the HIP records returned a DNS answer with
  RCODE=0 (No Error) and an empty answer section, it means that no HIP
  information is available at the responder name.  In such a case, if
  the Initiator has been configured with a policy to fallback to
  opportunistic HIP (initiating without knowing the Responder's HI) or
  plain IP, it would send out more queries for A and AAAA types at the
  Responder's FQDN.

  Depending on the combinations of answers, the situations described in
  Section 3.1 and Section 3.2 can occur.

  Note that storing HIP RR information in the DNS at an FQDN that is
  assigned to a non-HIP node might have ill effects on its reachability
  by HIP nodes.

3.1.  Simple Static Singly Homed End-Host

  A HIP node (R) with a single static network attachment, wishing to be
  reachable by reference to its FQDN (www.example.com), would store in
  the DNS, in addition to its IP address(es) (IP-R), its Host Identity
  (HI-R) and Host Identity Tag (HIT-R) in a HIP resource record.

  An Initiator willing to associate with a node would typically issue
  the following queries:

  o  QNAME=www.example.com, QTYPE=HIP

  o  (QCLASS=IN is assumed and omitted from the examples)

  Which returns a DNS packet with RCODE=0 and one or more HIP RRs with
  the HIT and HI (e.g., HIT-R and HI-R) of the Responder in the answer
  section, but no RVS.








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  o  QNAME=www.example.com, QTYPE=A QNAME=www.example.com, QTYPE=AAAA

  Which returns DNS packets with RCODE=0 and one or more A or AAAA RRs
  containing IP address(es) of the Responder (e.g., IP-R) in the answer
  section.

  Caption: In the remainder of this document, for the sake of keeping
           diagrams simple and concise, several DNS queries and answers
           are represented as one single transaction, while in fact
           there are several queries and answers flowing back and
           forth, as described in the textual examples.

              [HIP? A?        ]
              [www.example.com]            +-----+
         +-------------------------------->|     |
         |                                 | DNS |
         | +-------------------------------|     |
         | |  [HIP? A?        ]            +-----+
         | |  [www.example.com]
         | |  [HIP HIT-R HI-R ]
         | |  [A IP-R         ]
         | v
       +-----+                              +-----+
       |     |--------------I1------------->|     |
       |  I  |<-------------R1--------------|  R  |
       |     |--------------I2------------->|     |
       |     |<-------------R2--------------|     |
       +-----+                              +-----+

                        Static Singly Homed Host

  The Initiator would then send an I1 to the Responder's IP addresses
  (IP-R).

3.2.  Mobile end-host

  A mobile HIP node (R) wishing to be reachable by reference to its
  FQDN (www.example.com) would store in the DNS, possibly in addition
  to its IP address(es) (IP-R), its HI (HI-R), HIT (HIT-R), and the
  domain name(s) of its rendezvous server(s) (e.g., rvs.example.com) in
  HIP resource record(s).  The mobile HIP node also needs to notify its
  rendezvous servers of any change in its set of IP address(es).

  An Initiator willing to associate with such a mobile node would
  typically issue the following queries:

  o  QNAME=www.example.com, QTYPE=HIP




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  Which returns a DNS packet with RCODE=0 and one or more HIP RRs with
  the HIT, HI, and RVS domain name(s) (e.g., HIT-R, HI-R, and
  rvs.example.com) of the Responder in the answer section.

  o  QNAME=rvs.example.com, QTYPE=A QNAME=www.example.com, QTYPE=AAAA

  Which returns DNS packets with RCODE=0 and one or more A or AAAA RRs
  containing IP address(es) of the Responder's RVS (e.g., IP-RVS) in
  the answer section.

             [HIP?           ]
             [www.example.com]

             [A?             ]
             [rvs.example.com]                     +-----+
        +----------------------------------------->|     |
        |                                          | DNS |
        | +----------------------------------------|     |
        | |  [HIP?                          ]      +-----+
        | |  [www.example.com               ]
        | |  [HIP HIT-R HI-R rvs.example.com]
        | |
        | |  [A?             ]
        | |  [rvs.example.com]
        | |  [A IP-RVS       ]
        | |
        | |                +-----+
        | | +------I1----->| RVS |-----I1------+
        | | |              +-----+             |
        | | |                                  |
        | | |                                  |
        | v |                                  v
       +-----+                              +-----+
       |     |<---------------R1------------|     |
       |  I  |----------------I2----------->|  R  |
       |     |<---------------R2------------|     |
       +-----+                              +-----+

                             Mobile End-Host

  The Initiator would then send an I1 to the RVS IP address (IP-RVS).
  Following, the RVS will relay the I1 up to the mobile node's IP
  address (IP-R), which will complete the HIP exchange.








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4.  Overview of Using the DNS with HIP

4.1.  Storing HI, HIT, and RVS in the DNS

  For any HIP node, its Host Identity (HI), the associated Host
  Identity Tag (HIT), and the FQDN of its possible RVSs can be stored
  in a DNS HIP RR.  Any conforming implementation may store a Host
  Identity (HI) and its associated Host Identity Tag (HIT) in a DNS HIP
  RDATA format.  HI and HIT are defined in Section 3 of the HIP
  specification [RFC5201].

  Upon return of a HIP RR, a host MUST always calculate the HI-
  derivative HIT to be used in the HIP exchange, as specified in
  Section 3 of the HIP specification [RFC5201], while the HIT possibly
  embedded along SHOULD only be used as an optimization (e.g., table
  lookup).

  The HIP resource record may also contain one or more domain name(s)
  of rendezvous server(s) towards which HIP I1 packets might be sent to
  trigger the establishment of an association with the entity named by
  this resource record [RFC5204].

  The rendezvous server field of the HIP resource record stored at a
  given owner name MAY include the owner name itself.  A semantically
  equivalent situation occurs if no rendezvous server is present in the
  HIP resource record stored at that owner name.  Such situations occur
  in two cases:

  o  The host is mobile, and the A and/or AAAA resource record(s)
     stored at its host name contain the IP address(es) of its
     rendezvous server rather than its own one.

  o  The host is stationary, and can be reached directly at the IP
     address(es) contained in the A and/or AAAA resource record(s)
     stored at its host name.  This is a degenerated case of rendezvous
     service where the host somewhat acts as a rendezvous server for
     itself.

  An RVS receiving such an I1 would then relay it to the appropriate
  Responder (the owner of the I1 receiver HIT).  The Responder will
  then complete the exchange with the Initiator, typically without
  ongoing help from the RVS.

4.2.  Initiating Connections Based on DNS Names

  On a HIP node, a Host Identity Protocol exchange SHOULD be initiated
  whenever a ULP attempts to communicate with an entity and the DNS
  lookup returns HIP resource records.



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5.  HIP RR Storage Format

  The RDATA for a HIP RR consists of a public key algorithm type, the
  HIT length, a HIT, a public key, and optionally one or more
  rendezvous server(s).

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |  HIT length   | PK algorithm  |          PK length            |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                                                               |
  ~                           HIT                                 ~
  |                                                               |
  +                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                     |                                         |
  +-+-+-+-+-+-+-+-+-+-+-+                                         +
  |                           Public Key                          |
  ~                                                               ~
  |                                                               |
  +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                               |                               |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
  |                                                               |
  ~                       Rendezvous Servers                      ~
  |                                                               |
  +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |             |
  +-+-+-+-+-+-+-+

  The HIT length, PK algorithm, PK length, HIT, and Public Key fields
  are REQUIRED.  The Rendezvous Servers field is OPTIONAL.

5.1.  HIT Length Format

  The HIT length indicates the length in bytes of the HIT field.  This
  is an 8-bit unsigned integer.

5.2.  PK Algorithm Format

  The PK algorithm field indicates the public key cryptographic
  algorithm and the implied public key field format.  This is an 8-bit
  unsigned integer.  This document reuses the values defined for the
  'algorithm type' of the IPSECKEY RR [RFC4025].

  Presently defined values are listed in Section 9 for reference.





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5.3.  PK Length Format

  The PK length indicates the length in bytes of the Public key field.
  This is a 16-bit unsigned integer in network byte order.

5.4.  HIT Format

  The HIT is stored as a binary value in network byte order.

5.5.  Public Key Format

  Both of the public key types defined in this document (RSA and DSA)
  reuse the public key formats defined for the IPSECKEY RR [RFC4025].

  The DSA key format is defined in RFC 2536 [RFC2536].

  The RSA key format is defined in RFC 3110 [RFC3110] and the RSA key
  size limit (4096 bits) is relaxed in the IPSECKEY RR [RFC4025]
  specification.

5.6.  Rendezvous Servers Format

  The Rendezvous Servers field indicates one or more variable length
  wire-encoded domain names of rendezvous server(s), as described in
  Section 3.3 of RFC 1035 [RFC1035].  The wire-encoded format is self-
  describing, so the length is implicit.  The domain names MUST NOT be
  compressed.  The rendezvous server(s) are listed in order of
  preference (i.e., first rendezvous server(s) are preferred), defining
  an implicit order amongst rendezvous servers of a single RR.  When
  multiple HIP RRs are present at the same owner name, this implicit
  order of rendezvous servers within an RR MUST NOT be used to infer a
  preference order between rendezvous servers stored in different RRs.

6.  HIP RR Presentation Format

  This section specifies the representation of the HIP RR in a zone
  master file.

  The HIT length field is not represented, as it is implicitly known
  thanks to the HIT field representation.

  The PK algorithm field is represented as unsigned integers.

  The HIT field is represented as the Base16 encoding [RFC4648] (a.k.a.
  hex or hexadecimal) of the HIT.  The encoding MUST NOT contain
  whitespaces to distinguish it from the public key field.





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  The Public Key field is represented as the Base64 encoding [RFC4648]
  of the public key.  The encoding MUST NOT contain whitespace(s) to
  distinguish it from the Rendezvous Servers field.

  The PK length field is not represented, as it is implicitly known
  thanks to the Public key field representation containing no
  whitespaces.

  The Rendezvous Servers field is represented by one or more domain
  name(s) separated by whitespace(s).

  The complete representation of the HPIHI record is:

  IN  HIP   ( pk-algorithm
              base16-encoded-hit
              base64-encoded-public-key
              rendezvous-server[1]
                      ...
              rendezvous-server[n] )

  When no RVSs are present, the representation of the HPIHI record is:

  IN  HIP   ( pk-algorithm
              base16-encoded-hit
              base64-encoded-public-key )

7.  Examples

  In the examples below, the public key field containing no whitespace
  is wrapped since it does not fit in a single line of this document.

  Example of a node with HI and HIT but no RVS:

www.example.com.      IN  HIP ( 2 200100107B1A74DF365639CC39F1D578
                               AwEAAbdxyhNuSutc5EMzxTs9LBPCIkOFH8cIvM4p
9+LrV4e19WzK00+CI6zBCQTdtWsuxKbWIy87UOoJTwkUs7lBu+Upr1gsNrut79ryra+bSRGQ
b1slImA8YVJyuIDsj7kwzG7jnERNqnWxZ48AWkskmdHaVDP4BcelrTI3rMXdXF5D )

  Example of a node with a HI, HIT, and one RVS:

www.example.com.      IN  HIP ( 2 200100107B1A74DF365639CC39F1D578
                               AwEAAbdxyhNuSutc5EMzxTs9LBPCIkOFH8cIvM4p
9+LrV4e19WzK00+CI6zBCQTdtWsuxKbWIy87UOoJTwkUs7lBu+Upr1gsNrut79ryra+bSRGQ
b1slImA8YVJyuIDsj7kwzG7jnERNqnWxZ48AWkskmdHaVDP4BcelrTI3rMXdXF5D
                               rvs.example.com. )






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  Example of a node with a HI, HIT, and two RVSs:

www.example.com.      IN  HIP ( 2 200100107B1A74DF365639CC39F1D578
                               AwEAAbdxyhNuSutc5EMzxTs9LBPCIkOFH8cIvM4p
9+LrV4e19WzK00+CI6zBCQTdtWsuxKbWIy87UOoJTwkUs7lBu+Upr1gsNrut79ryra+bSRGQ
b1slImA8YVJyuIDsj7kwzG7jnERNqnWxZ48AWkskmdHaVDP4BcelrTI3rMXdXF5D
                               rvs1.example.com.
                               rvs2.example.com. )

8.  Security Considerations

  This section contains a description of the known threats involved
  with the usage of the HIP DNS Extension.

  In a manner similar to the IPSECKEY RR [RFC4025], the HIP DNS
  Extension allows for the provision of two HIP nodes with the public
  keying material (HI) of their peer.  These HIs will be subsequently
  used in a key exchange between the peers.  Hence, the HIP DNS
  Extension introduces the same kind of threats that IPSECKEY does,
  plus threats caused by the possibility given to a HIP node to
  initiate or accept a HIP exchange using "opportunistic" or
  "unpublished Initiator HI" modes.

  A HIP node SHOULD obtain HIP RRs from a trusted party trough a secure
  channel ensuring data integrity and authenticity of the RRs.  DNSSEC
  [RFC4033] [RFC4034] [RFC4035] provides such a secure channel.
  However, it should be emphasized that DNSSEC only offers data
  integrity and authenticity guarantees to the channel between the DNS
  server publishing a zone and the HIP node.  DNSSEC does not ensure
  that the entity publishing the zone is trusted.  Therefore, the RRSIG
  signature of the HIP RRSet MUST NOT be misinterpreted as a
  certificate binding the HI and/or the HIT to the owner name.

  In the absence of a proper secure channel, both parties are
  vulnerable to MitM and DoS attacks, and unrelated parties might be
  subject to DoS attacks as well.  These threats are described in the
  following sections.

8.1.  Attacker Tampering with an Insecure HIP RR

  The HIP RR contains public keying material in the form of the named
  peer's public key (the HI) and its secure hash (the HIT).  Both of
  these are not sensitive to attacks where an adversary gains knowledge
  of them.  However, an attacker that is able to mount an active attack
  on the DNS, i.e., tampers with this HIP RR (e.g., using DNS
  spoofing), is able to mount Man-in-the-Middle attacks on the
  cryptographic core of the eventual HIP exchange (Responder's HIP RR
  rewritten by the attacker).



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  The HIP RR may contain a rendezvous server domain name resolved into
  a destination IP address where the named peer is reachable by an I1,
  as per the HIP Rendezvous Extension [RFC5204].  Thus, an attacker
  able to tamper with this RR is able to redirect I1 packets sent to
  the named peer to a chosen IP address for DoS or MitM attacks.  Note
  that this kind of attack is not specific to HIP and exists
  independently of whether or not HIP and the HIP RR are used.  Such an
  attacker might tamper with A and AAAA RRs as well.

  An attacker might obviously use these two attacks in conjunction: It
  will replace the Responder's HI and RVS IP address by its own in a
  spoofed DNS packet sent to the Initiator HI, then redirect all
  exchanged packets to him and mount a MitM on HIP.  In this case, HIP
  won't provide confidentiality nor Initiator HI protection from
  eavesdroppers.

8.2.  Hash and HITs Collisions

  As with many cryptographic algorithms, some secure hashes (e.g.,
  SHA1, used by HIP to generate a HIT from an HI) eventually become
  insecure, because an exploit has been found in which an attacker with
  reasonable computation power breaks one of the security features of
  the hash (e.g., its supposed collision resistance).  This is why a
  HIP end-node implementation SHOULD NOT authenticate its HIP peers
  based solely on a HIT retrieved from the DNS, but SHOULD rather use
  HI-based authentication.

8.3.  DNSSEC

  In the absence of DNSSEC, the HIP RR is subject to the threats
  described in RFC 3833 [RFC3833].

9.  IANA Considerations

  IANA has allocated one new RR type code (55) for the HIP RR from the
  standard RR type space.

  IANA does not need to open a new registry for public key algorithms
  of the HIP RR because the HIP RR reuses "algorithms types" defined
  for the IPSECKEY RR [RFC4025].  Presently defined values are shown
  here for reference only:

     0 is reserved

     1 is DSA

     2 is RSA




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  In the future, if a new algorithm is to be used for the HIP RR, a new
  algorithm type and corresponding public key encoding should be
  defined for the IPSECKEY RR.  The HIP RR should reuse both the same
  algorithm type and the same corresponding public key format as the
  IPSECKEY RR.

10.  Acknowledgments

  As usual in the IETF, this document is the result of a collaboration
  between many people.  The authors would like to thank the author
  (Michael Richardson), contributors, and reviewers of the IPSECKEY RR
  [RFC4025] specification, after which this document was framed.  The
  authors would also like to thank the following people, who have
  provided thoughtful and helpful discussions and/or suggestions, that
  have helped improve this document: Jeff Ahrenholz, Rob Austein, Hannu
  Flinck, Olafur Gudmundsson, Tom Henderson, Peter Koch, Olaf Kolkman,
  Miika Komu, Andrew McGregor, Erik Nordmark, and Gabriel Montenegro.
  Some parts of this document stem from the HIP specification
  [RFC5201].

11.  References

11.1.  Normative references

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

  [RFC1035]  Mockapetris, P., "Domain names - implementation and
             specification", STD 13, RFC 1035, November 1987.

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

  [RFC2181]  Elz, R. and R. Bush, "Clarifications to the DNS
             Specification", RFC 2181, July 1997.

  [RFC3596]  Thomson, S., Huitema, C., Ksinant, V., and M. Souissi,
             "DNS Extensions to Support IP Version 6", RFC 3596,
             October 2003.

  [RFC4025]  Richardson, M., "A Method for Storing IPsec Keying
             Material in DNS", RFC 4025, March 2005.

  [RFC4033]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
             Rose, "DNS Security Introduction and Requirements",
             RFC 4033, March 2005.





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  [RFC4034]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
             Rose, "Resource Records for the DNS Security Extensions",
             RFC 4034, March 2005.

  [RFC4035]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
             Rose, "Protocol Modifications for the DNS Security
             Extensions", RFC 4035, March 2005.

  [RFC4648]  Josefsson, S., "The Base16, Base32, and Base64 Data
             Encodings", RFC 4648, October 2006.

  [RFC5201]  Moskowitz, R., Nikander, P., Jokela, P., Ed., and T.
             Henderson, "Host Identity Protocol", RFC 5201, April 2008.

  [RFC5204]  Laganier, J. and L. Eggert, "Host Identity Protocol (HIP)
             Rendezvous Extension", RFC 5204, April 2008.

11.2.  Informative references

  [RFC2536]  Eastlake, D., "DSA KEYs and SIGs in the Domain Name System
             (DNS)", RFC 2536, March 1999.

  [RFC3110]  Eastlake, D., "RSA/SHA-1 SIGs and RSA KEYs in the Domain
             Name System (DNS)", RFC 3110, May 2001.

  [RFC3833]  Atkins, D. and R. Austein, "Threat Analysis of the Domain
             Name System (DNS)", RFC 3833, August 2004.

  [RFC4423]  Moskowitz, R. and P. Nikander, "Host Identity Protocol
             (HIP) Architecture", RFC 4423, May 2006.

  [RFC5206]  Henderson, T., Ed., "End-Host Mobility and Multihoming
             with the Host Identity Protocol", RFC 5206, April 2008.


















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Authors' Addresses

  Pekka Nikander
  Ericsson Research NomadicLab
  JORVAS  FIN-02420
  FINLAND

  Phone: +358 9 299 1
  EMail: [email protected]


  Julien Laganier
  DoCoMo Communications Laboratories Europe GmbH
  Landsberger Strasse 312
  Munich  80687
  Germany

  Phone: +49 89 56824 231
  EMail: [email protected]
  URI:   http://www.docomolab-euro.com/































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Full Copyright Statement

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