Identity-Based Signatures for Mobile Ad Hoc Network (MANET) Routing Protocols
RFC 7859

Internet Engineering Task Force (IETF)                       C. Dearlove
Request for Comments: 7859                                   BAE Systems
Category: Experimental                                          May 2016
ISSN: 2070-1721

                     Identity-Based Signatures for
            Mobile Ad Hoc Network (MANET) Routing Protocols

Abstract

   This document extends RFC 7182, which specifies a framework for (and
   specific examples of) Integrity Check Values (ICVs) for packets and
   messages using the generalized packet/message format specified in RFC
   5444.  It does so by defining an additional cryptographic function
   that allows the creation of an ICV that is an Identity-Based
   Signature (IBS), defined according to the Elliptic Curve-Based
   Certificateless Signatures for Identity-Based Encryption (ECCSI)
   algorithm specified in RFC 6507.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for examination, experimental implementation, and
   evaluation.

   This document defines an Experimental Protocol for the Internet
   community.  This document is a product of the Internet Engineering
   Task Force (IETF).  It represents the consensus of the IETF
   community.  It has received public review and has been approved for
   publication by the Internet Engineering Steering Group (IESG).  Not
   all documents approved by the IESG are a candidate for any level of
   Internet Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7859.

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Copyright Notice

   Copyright (c) 2016 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
   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Applicability Statement . . . . . . . . . . . . . . . . . . .   5
   4.  Specification . . . . . . . . . . . . . . . . . . . . . . . .   5
     4.1.  Cryptographic Function  . . . . . . . . . . . . . . . . .   5
     4.2.  ECCSI Parameters  . . . . . . . . . . . . . . . . . . . .   6
     4.3.  Identity  . . . . . . . . . . . . . . . . . . . . . . . .   7
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
     6.1.  Experimental Status . . . . . . . . . . . . . . . . . . .   9
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Appendix A.  Example  . . . . . . . . . . . . . . . . . . . . . .  12
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  17
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  17

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1.  Introduction

   [RFC7182] defines Integrity Check Value (ICV) TLVs for use in packets
   and messages that use the generalized MANET packet/message format
   defined in [RFC5444].  This specification extends the TLV definitions
   therein by defining two new cryptographic function code points from
   within the registries set up by [RFC7182].  This allows the use of an
   Identity-Based Signature (IBS) as an ICV.  An IBS has an additional
   property that is not shared by all of the previously specified ICVs;
   it not only indicates that the protected packet or message is valid,
   but also verifies the originator of the packet/message.

   This specification assumes that each router (i.e., each originator of
   [RFC5444] format packets/messages) has an identity that may be tied
   to the packet or message.  The router may have more than one identity
   but will only use one for each ICV TLV.  The cryptographic strength
   of the IBS is not dependent on the choice of identity.

   Two options for the choice of identity are supported (as reflected by
   the two code points allocated).  In the first option, the identity
   can be any octet sequence (up to 255 octets) included in the ICV TLV.
   In the second option, the octet sequence is preceded by an address,
   either the IP source address for a Packet TLV or the message
   originator address for a Message TLV or an Address Block TLV.  In
   particular, the second option allows just the address to be used as
   an identity.

   Identity-based signatures allow identification of the originator of
   information in a packet or message.  They thus allow additional
   security functions, such as revocation of an identity.  (A router
   could also then remove all information recorded as from that revoked
   originator; the Optimized Link State Routing Protocol Version 2
   (OLSRv2) [RFC7181], an expected user of this specification, can do
   this.)  When applied to messages (rather than packets), this can
   significantly reduce the damage that a compromised router can inflict
   on the network.

   Identity-based signatures are based on forms of asymmetric (public
   key) cryptography - Identity-Based Encryption (IBE).  Compared to
   symmetric cryptographic methods (such as HMAC and AES), IBE and IBS
   methods avoid requiring a shared secret key that results in a single
   point of failure vulnerability.  Compared to more widely used
   asymmetric (public key) cryptographic methods (such as RSA and
   ECDSA), IBE and IBS methods have a major advantage and a major
   disadvantage.

   The advantage referred to is that each router can be configured once
   (for its key lifetime) by a trusted authority, independently of all

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   other routers.  Thus, a router can connect to the authority
   (typically in a secure environment) to receive a private key or can
   have a private key delivered securely (out of band) from the
   authority.  During normal operation of the MANET, there is no need
   for the trusted authority to be connected to the MANET or even to
   still exist.  Additional routers can be authorized with no reference
   to previously authorized routers (the trusted authority must still
   exist in this case).  A router's public key is its identity, which
   when tied to a packet or message (as is the case when using an
   address as, or as part of, the identity) means that there is no need
   for public key certificates or a certificate authority, and a router
   need not retain key material for any other routers.

   The disadvantage referred to is that the trusted authority has
   complete authority, even more so than a conventional certificate
   authority.  Routers cannot generate their own private keys, only the
   trusted authority can do that.  Through the master secret held by the
   trusted authority, it could impersonate any router (existing or not).
   When used for IBE (not part of this specification), the trusted
   authority can decrypt anything.  However, note that the shared secret
   key options described in [RFC7182] also have this limitation.

   There are alternative mathematical realizations of identity-based
   signatures.  This specification uses one that has been previously
   published as [RFC6507], known as Elliptic Curve-Based Certificateless
   Signatures for Identity-Based Encryption (ECCSI).  Similar to other
   IBE/IBS approaches, it is based on the use of elliptic curves.
   Unlike some, it does not use "pairings" (bilinear maps from a product
   of two elliptic curve groups to another group).  It thus may be
   easier to implement and more efficient than some alternatives,
   although with a greater signature size than some.  This specification
   allows the use of any elliptic curve that may be used by [RFC6507].

   The computational load imposed by ECCSI (and, perhaps more so by
   other IBS methods) is not trivial, though it depends significantly on
   the quality of implementation of the required elliptic curve and
   other mathematical functions.  For a security level of 128 bits, the
   ICV data length is 129 octets, which is longer than for alternative
   ICVs specified in [RFC7182] (e.g., 32 octets for the similar strength
   HMAC-SHA-256).  The signature format used could have been slightly
   shortened (to 97 octets) by using a compressed representation of an
   elliptic curve point, however, at the expense of some additional work
   when verifying a signature and loss of direct compatibility with
   [RFC6507], and implementations thereof.

   The trusted authority is referred to in [RFC6507] as the Key
   Management Service (KMS).  That term will be used in the rest of this
   specification.

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2.  Terminology

   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].

   Additionally, this document uses the terminology of [RFC5444],
   [RFC6507], and [RFC7182].

3.  Applicability Statement

   This specification adds an additional option to the framework
   specified in [RFC7182] for use by packets and messages formatted as
   described in [RFC5444].  It is applicable as described in [RFC7182]
   and is subject to the additional comments in Section 6, particularly
   regarding the role of the trusted authority (KMS).

   Specific examples of protocols for which this specification is
   suitable are Neighborhood Discovery Protocol (NHDP) [RFC6130] and
   OLSRv2 [RFC7181].

4.  Specification

4.1.  Cryptographic Function

   This specification defines a cryptographic function named ECCSI that
   is implemented as specified as the "sign" function in Section 5.2.1
   of [RFC6507].  To use that specification:

   o  The ICV is not calculated as cryptographic-function(hash-
      function(content)) as defined in [RFC7182] but (like the HMAC ICVs
      defined in [RFC7182]) uses the hash function within the
      cryptographic function.  The option "none" is not permitted for
      hash-function, and the hash function must have a known fixed
      length of N octets (as specified in Section 4.2).

   o  M, used in [RFC6507], is "content" as specified in [RFC7182].

   o  ID, used in [RFC6507], is as specified in Section 4.3.

   o  Key Management Service Public Authentication Key (KPAK), Secret
      Signing Key (SSK), and Public Validation Token (PVT), which are
      provided by the KMS, are as specified in Sections 4.2 and 5.1.1 of
      [RFC6507].

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   The length of the signature is 4N+1 octets (as specified in
   [RFC6507]) whose affine coordinate format (including an octet valued
   0x04 to identify this) is used unchanged.

   Verification of the ICV is not implemented by the receiver
   recalculating the ICV and comparing with the received ICV, as it is
   necessarily incapable of doing so.  Instead, the receiver evaluates
   the "verify" function described in Section 5.2.2 of [RFC6507], which
   may pass or fail.

   To use that function M, KPAK, SSK, and PVT are as specified above,
   while the Identifier (ID) is deduced from the received packet or
   message (as specified in Section 4.3) using the <key-id> element in
   the <ICV-value>.  This element need not match that used by the
   receiver, and thus when using this cryptographic function, multiple
   ICV TLVs differing only in their <key-id> or in the choice of
   cryptographic function from the two defined in this specification
   SHOULD NOT be used unless routers are administratively configured to
   recognize which to verify.

   Routers MAY be administratively configured to reject an ICV TLV using
   ECCSI based on part or all of <key-id>: for example, if this encodes
   a time after which this identity is no longer valid (as described in
   Section 4.3).

4.2.  ECCSI Parameters

   Section 4.1 of [RFC6507] specifies parameters n, N, p, E, B, G, and
   q.  The first of these, n, is specified as "A security parameter; the
   size in bits of the prime p over which elliptic curve cryptography is
   to be performed."  For typical security levels (e.g., 128, 192, and
   256 bits), n must be at least twice the required bits of security;
   see Section 5.6.1 of [NIST-SP-800-57].

   Selection of an elliptic curve, and all related parameters, MUST be
   made by administrative means, and known to all routers.  Following
   [RFC6507], it is RECOMMENDED that the curves and base points defined
   in Appendix D.1.2 of [NIST-FIPS-186-4] be used (note that n in that
   document is q in [RFC6507]).  However, an alternative curve MAY be
   used.

   The parameter that is required by this specification is N, which is
   defined as Ceiling(n/8).  The hash function used must create an
   output of size N octets.  For example, for 128 bit security, with n =
   256 and N = 32, the RECOMMENDED hash function is SHA-256.  The
   signature (i.e., <ICV-data>) length is 4N+1 octets, i.e., 129 octets
   for N = 32.

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   Note that [RFC6507] actually refers to the predecessor to
   [NIST-FIPS-186-4], but the latest version is specified here; there
   are no significant differences in this regard.

4.3.  Identity

   There are two options for ID as used by [RFC6507], which are
   indicated by there being two code points allocated for this
   cryptographic function, see Section 5.

   o  For the cryptographic function ECCSI, ID is the element <key-id>
      defined in Section 12.1 of [RFC7182].  This MUST NOT be empty.

   o  For the cryptographic function ECCSI-ADDR, ID is the concatenation
      of an address (in network byte order) and the element <key-id>
      defined in Section 12.1 of [RFC7182], where the latter MAY be
      empty.

      *  For a Packet TLV, this address is the IP source address of the
         IP datagram in which this packet is included.

      *  For a Message TLV or an Address Block TLV, this address is the
         message originator address (the element <msg-orig-addr> defined
         in [RFC5444]) if that address is present; if it is not present
         and the message is known to have traveled only one hop, then
         the IP source address of the IP datagram in which this message
         is included is used.  Otherwise, no address is defined and the
         message MUST be rejected.  (Note that HELLO messages specified
         in NHDP [RFC6130] and used in OLSRv2 [RFC7181] always only
         travel one hop; hence, their IP source address SHOULD be used
         if no originator address is present.)

   The element <key-id> MAY be (for the cryptographic function ECCSI-
   ADDR) or include (for either cryptographic function) a representation
   of the identity expiry time.  This MAY use one of the representations
   of time defined for the TIMESTAMP TLV in [RFC7182].  A RECOMMENDED
   approach is to use the cryptographic function ECCSI-ADDR with element
   <key-id> containing the single octet representing the type of the
   time, normally used as the TIMESTAMP TLV Type Extension (defined in
   [RFC7182], Table 9), or any extension thereof, followed by the time
   as so represented, normally used as the TIMESTAMP TLV Value.

   Note that the identity is formatted as specified in [RFC6507] and
   thus does not need a length field incorporated into it by this
   specification.

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5.  IANA Considerations

   IANA has allocated the following two new values in the "Cryptographic
   Functions" registry under "Mobile Ad Hoc NETwork Parameters" registry
   and modified the unassigned range accordingly.

   +-------+------------+----------------------------------+-----------+
   | Value | Algorithm  |           Description            | Reference |
   +-------+------------+----------------------------------+-----------+
   |   7   |   ECCSI    |         ECCSI [RFC6507]          |  RFC 7859 |
   |   8   | ECCSI-ADDR | ECCSI [RFC6507] with an address  |  RFC 7859 |
   |       |            | (source or originator) joined to |           |
   |       |            |             identity             |           |
   | 9-251 |            |    Unassigned; Expert Review     |           |
   +-------+------------+----------------------------------+-----------+

                 Table 1: Cryptographic Function Registry

6.  Security Considerations

   This specification extends the security framework for MANET routing
   protocols specified in [RFC7182] by adding cryptographic functions
   (in two forms, according to how identity is specified).

   This cryptographic function implements a form of IBS; a stronger form
   of ICV that verifies not just that the received packet or message is
   valid but that the packet or message originated at a router that was
   assigned a private key for the specified identity.

   It is recommended that the identity include an address unique to that
   router: for a message, its originator address, and for a packet, the
   corresponding IP packet source address.  If additional information is
   included in the identity, this may be to indicate an expiry time for
   signatures created using that identity.

   In common with other forms of IBS, a feature of the form of IBS
   (known as ECCSI) used in this specification is that it requires a
   trusted KMS that issues all private keys and has complete
   cryptographic information about all possible private keys.  However,
   to set against that, the solution is scalable (as all routers can be
   independently keyed) and does not need the KMS in the network.  If no
   future keys will be required, then the KMS's master secret can be
   destroyed.  As routers are individually keyed, key revocation (by
   blacklist and/or time expiry of keys) is possible.

   ECCSI is based on elliptic curve mathematics.  This specification
   follows [RFC6507] in its recommendation of elliptic curves, but any
   suitable (prime power) elliptic curve may be used; this must be

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   administratively specified.  Implementation of this specification
   will require an available implementation of suitable mathematical
   functions.  Unlike some other forms of IBS, ECCSI requires only basic
   elliptic curve operations; it does not require "pairings" (bilinear
   functions of a product of two elliptic curve groups).  This increases
   the available range of suitable mathematical libraries.

6.1.  Experimental Status

   The idea of using identity-based signatures for authentication of ad
   hoc network signaling goes back at least as far as 2005 [Dearlove].
   The specific implementation of an IBS used in this specification,
   ECCSI, was published as an Internet Draft in 2010 before publication
   as an Informational RFC [RFC6507].  ECCSI is now part of standards
   such as [ETSI] for LTE Proximity-based Services.  An open-source
   implementation of cryptographic software that includes ECCSI is
   available, see [SecureChorus].

   However, although this specification has been implemented for use in
   an OLSRv2 [RFC7181] routed network, there are only limited reports of
   such use.  There are also no reports of the use of ECCSI within the
   IETF, other than in this specification.  There are no reports of
   independent public scrutiny of the algorithm, although ECCSI is
   reported [RFC6507] as being based on [ECDSA] with similar properties.

   This specification is thus published as Experimental in order to
   encourage its use and encourage reports on its use.  Once experiments
   have been carried out and reported on (and when some public analysis
   of the underlying cryptographic algorithms is available), it is
   intended to advance this specification, with any changes identified
   by such experimentation and analysis, to Standards Track.

7.  References

7.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC5444]  Clausen, T., Dearlove, C., Dean, J., and C. Adjih,
              "Generalized Mobile Ad Hoc Network (MANET) Packet/Message
              Format", RFC 5444, DOI 10.17487/RFC5444, February 2009,
              <http://www.rfc-editor.org/info/rfc5444>.

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   [RFC6507]  Groves, M., "Elliptic Curve-Based Certificateless
              Signatures for Identity-Based Encryption (ECCSI)",
              RFC 6507, DOI 10.17487/RFC6507, February 2012,
              <http://www.rfc-editor.org/info/rfc6507>.

   [RFC7182]  Herberg, U., Clausen, T., and C. Dearlove, "Integrity
              Check Value and Timestamp TLV Definitions for Mobile Ad
              Hoc Networks (MANETs)", RFC 7182, DOI 10.17487/RFC7182,
              April 2014, <http://www.rfc-editor.org/info/rfc7182>.

7.2.  Informative References

   [Dearlove] Dearlove, C., "OLSR Developments and Extensions",
              Proceedings of the 2nd OLSR Interop and Workshop, July
              2005, <http://interop.thomasclausen.org/Interop05/Papers/
              Papers/paper-01.pdf>.

   [ECDSA]    American National Standards Institute, "Public Key
              Cryptography for the Financial Services Industry: The
              Elliptic Curve Digital Signature Algorithm (ECDSA)",
              ANSI X9.62-2005, November 2005.

   [ETSI]     ETSI/3GPP, "Universal Mobile Telecommunications System
              (UMTS); LTE; Proximity-based Services (ProSe); Security
              aspects", ETSI TS 33.303, V13.2.0, Release 13, January
              2016, <http://www.etsi.org/deliver/
              etsi_ts/133300_133399/133303/13.02.00_60/
              ts_133303v130200p.pdf>.

   [NIST-FIPS-186-4]
              National Institute of Standards and Technology, "Digital
              Signature Standard (DSS)", FIPS 186-4,
              DOI 10.6028/NIST.FIPS.186-4, July 2013.

   [NIST-SP-800-57]
              National Institute of Standards and Technology,
              "Recommendation for Key Management - Part 1: General
              (Revision 3)", NIST Special Publication 800-57, Part 1,
              Revision 3, DOI 10.6028/NIST.SP.800-57pt1r4, July 2012.

   [RFC5497]  Clausen, T. and C. Dearlove, "Representing Multi-Value
              Time in Mobile Ad Hoc Networks (MANETs)", RFC 5497,
              DOI 10.17487/RFC5497, March 2009,
              <http://www.rfc-editor.org/info/rfc5497>.

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   [RFC6130]  Clausen, T., Dearlove, C., and J. Dean, "Mobile Ad Hoc
              Network (MANET) Neighborhood Discovery Protocol (NHDP)",
              RFC 6130, DOI 10.17487/RFC6130, April 2011,
              <http://www.rfc-editor.org/info/rfc6130>.

   [RFC7181]  Clausen, T., Dearlove, C., Jacquet, P., and U. Herberg,
              "The Optimized Link State Routing Protocol Version 2",
              RFC 7181, DOI 10.17487/RFC7181, April 2014,
              <http://www.rfc-editor.org/info/rfc7181>.

   [SecureChorus]
              "Secure Chorus: Interoperable and secure enterprise
              communications", <http://www.securechorus.com/>.

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Appendix A.  Example

   Appendix C of [RFC6130] contains this example of a HELLO message.
   (Note that normally a TIMESTAMP ICV would also be added before the
   ICV TLV, but for simplicity, that step has been omitted here.)

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     HELLO     | MF=7  | MAL=3 |      Message Length = 45      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Hop Limit = 1 | Hop Count = 0 |    Message Sequence Number    |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Message TLV Block Length = 8  | VALIDITY_TIME |  MTLVF = 16   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Value Len = 1 | Value (Time)  | INTERVAL_TIME |  MTLVF = 16   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Value Len = 1 | Value (Time)  | Num Addrs = 5 |   ABF = 128   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Head Len = 3  |                     Head                      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Mid 0     |     Mid 1     |     Mid 2     |     Mid 3     |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Mid 4     | Address TLV Block Length = 14 |   LOCAL_IF    |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  ATLVF = 80   |   Index = 0   | Value Len = 1 |    THIS_IF    |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  LINK_STATUS  |   ATLV = 52   | Strt Indx = 1 | Stop Indx = 4 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Value Len = 4 |     HEARD     |     HEARD     |   SYMMETRIC   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     LOST      |
     +-+-+-+-+-+-+-+-+

   In order to provide an example of an ECCSI ICV Message TLV that may
   be added to this message, the fields shown need to all have numerical
   values, both by inserting defined numerical values (e.g., 0 for
   HELLO) and by selecting example values where needed.  The latter
   means that

   o  The message sequence number will be zero.

   o  The five addresses will be 192.0.2.1 to 192.0.2.5.

   o  The message validity time will be six seconds and the message
      interval time will be two seconds, each encoded with a constant
      value C = 1/1024 seconds (as described in [RFC5497] and as
      referenced from [RFC6130]).

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   In addition, when calculating an ICV, the hop count and hop limit are
   both set to zero.  This results in the message:

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 0 0 0 0 0 0 0|0 1 1 1 0 0 1 1|0 0 0 0 0 0 0 0 0 0 1 0 1 1 0 1|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0|0 0 0 0 0 0 0 1|0 0 0 1 0 0 0 0|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 0 0 0 0 0 0 1|0 1 1 0 0 1 0 0|0 0 0 0 0 0 0 0|0 0 0 1 0 0 0 0|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 0 0 0 0 0 0 1|0 1 0 1 1 0 0 0|0 0 0 0 0 1 0 1|1 0 0 0 0 0 0 0|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 0 0 0 0 0 1 1|1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 0 0 0 0 0 0 1|0 0 0 0 0 0 1 0|0 0 0 0 0 0 1 1|0 0 0 0 0 1 0 0|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 0 0 0 0 1 0 1|0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0|0 0 0 0 0 0 1 0|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 1 0 1 0 0 0 0|0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 1|0 0 0 0 0 0 0 0|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 0 0 0 0 0 1 1|0 0 1 1 0 1 0 0|0 0 0 0 0 0 0 1|0 0 0 0 0 1 0 0|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 0 0 0 0 1 0 0|0 0 0 0 0 0 1 0|0 0 0 0 0 0 1 0|0 0 0 0 0 0 0 1|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 0 0 0 0 0 0 0|
     +-+-+-+-+-+-+-+-+

   Or, in hexadecimal form:

      M         := 0x 0073002D  00000000  00080110  01640010
                      01580580  03C00002  01020304  05000E02
                      50000100  03340104  04020201  00

   The ICV TLV that will be added will have cryptographic function
   ECCSI-ADDR and hash function SHA-256.  This message has no originator
   address, but it travels a single hop and its IP source address can be
   used.  This will be assumed to be 192.0.2.0 with an empty <key-id>;
   thus, the sender's identity will be (in hexadecimal form):

      ID        := 0x  C0000200

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RFC 7859                Identity-Based Signatures               May 2016

   Parameters for [RFC6507] will thus be n = 256, N = 32.  The same
   parameters and master key will be used as in Appendix A of [RFC6507],
   i.e., the elliptic curve P-256, with parameters:

      p         := 0x  FFFFFFFF 00000001 00000000 00000000
                       00000000 FFFFFFFF FFFFFFFF FFFFFFFF

      B         := 0x  5AC635D8 AA3A93E7 B3EBBD55 769886BC
                       651D06B0 CC53B0F6 3BCE3C3E 27D2604B

      q         := 0x  FFFFFFFF 00000000 FFFFFFFF FFFFFFFF
                       BCE6FAAD A7179E84 F3B9CAC2 FC632551

      G         := 0x  04
                       6B17D1F2 E12C4247 F8BCE6E5 63A440F2
                       77037D81 2DEB33A0 F4A13945 D898C296
                       4FE342E2 FE1A7F9B 8EE7EB4A 7C0F9E16
                       2BCE3357 6B315ECE CBB64068 37BF51F5

      KSAK      := 0x  12345;

      KPAK      := 0x  04
                       50D4670B DE75244F 28D2838A 0D25558A
                       7A72686D 4522D4C8 273FB644 2AEBFA93
                       DBDD3755 1AFD263B 5DFD617F 3960C65A
                       8C298850 FF99F203 66DCE7D4 367217F4

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   The remaining steps to creating a private key for the ID use the same
   "random" value v as Appendix A of [RFC6507] and are:

      v         := 0x  23456

      PVT       := 0x  04
                       758A1427 79BE89E8 29E71984 CB40EF75
                       8CC4AD77 5FC5B9A3 E1C8ED52 F6FA36D9
                       A79D2476 92F4EDA3 A6BDAB77 D6AA6474
                       A464AE49 34663C52 65BA7018 BA091F79

      HS        := hash( 0x 04
                            6B17D1F2 E12C4247 F8BCE6E5 63A440F2
                            77037D81 2DEB33A0 F4A13945 D898C296
                            4FE342E2 FE1A7F9B 8EE7EB4A 7C0F9E16
                            2BCE3357 6B315ECE CBB64068 37BF51F5
                            04
                            50D4670B DE75244F 28D2838A 0D25558A
                            7A72686D 4522D4C8 273FB644 2AEBFA93
                            DBDD3755 1AFD263B 5DFD617F 3960C65A
                            8C298850 FF99F203 66DCE7D4 367217F4
                            C0000200
                            04
                            758A1427 79BE89E8 29E71984 CB40EF75
                            8CC4AD77 5FC5B9A3 E1C8ED52 F6FA36D9
                            A79D2476 92F4EDA3 A6BDAB77 D6AA6474
                            A464AE49 34663C52 65BA7018 BA091F79 )

                 = 0x  F64FFD76 D2EC3E87 BA670866 C0832B80
                       B740C2BA 016034C8 1A6F5E5B 5F9AD8F3

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   The remaining steps to creating a signature for M use the same
   "random" value j as Appendix A of [RFC6507] and are:

      j         := 0x  34567

      J         := 0x  04
                       269D4C8F DEB66A74 E4EF8C0D 5DCC597D
                       DFE6029C 2AFFC493 6008CD2C C1045D81
                       6DDA6A13 10F4B067 BD5DABDA D741B7CE
                       F36457E1 96B1BFA9 7FD5F8FB B3926ADB

      r         := 0x  269D4C8F DEB66A74 E4EF8C0D 5DCC597D
                       DFE6029C 2AFFC493 6008CD2C C1045D81

      HE        := hash( 0x
                         F64FFD76 D2EC3E87 BA670866 C0832B80
                         B740C2BA 016034C8 1A6F5E5B 5F9AD8F3
                         269D4C8F DEB66A74 E4EF8C0D 5DCC597D
                         DFE6029C 2AFFC493 6008CD2C C1045D81
                         0073002D 00000000 00080110 01640010
                         01580580 03C00002 01020304 05000E02
                         50000100 03340104 04020201 00       )

                 = 0x  FE236B30 CF72E060 28E229ED 5751D796
                       91DED33C 24D2F661 28EA0804 30D8A832

      s'        := 0x  C8C739D5 FB3EFB75 221CB818 8CAAB86A
                       2E2669CF 209EA622 7D7072BA A83C2509

      s         := 0x  C8C739D5 FB3EFB75 221CB818 8CAAB86A
                       2E2669CF 209EA622 7D7072BA A83C2509

      Signature := 0x  269D4C8F DEB66A74 E4EF8C0D 5DCC597D
                       DFE6029C 2AFFC493 6008CD2C C1045D81
                       C8C739D5 FB3EFB75 221CB818 8CAAB86A
                       2E2669CF 209EA622 7D7072BA A83C2509
                       04
                       758A1427 79BE89E8 29E71984 CB40EF75
                       8CC4AD77 5FC5B9A3 E1C8ED52 F6FA36D9
                       A79D2476 92F4EDA3 A6BDAB77 D6AA6474
                       A464AE49 34663C52 65BA7018 BA091F79

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RFC 7859                Identity-Based Signatures               May 2016

Acknowledgments

   The author would like to thank his colleagues who have been involved
   in identity-based security for ad hoc networks, including (in
   alphabetical order) Alan Cullen, Peter Smith, and Bill Williams.  He
   would also like to thank Benjamin Smith (INRIA/Ecole Polytechnique)
   for independently recreating the signature and other values in
   Appendix A to ensure their correctness, and Thomas Clausen (Ecole
   Polytechnique) for additional comments.

Author's Address

   Christopher Dearlove
   BAE Systems Applied Intelligence Laboratories
   West Hanningfield Road
   Great Baddow, Chelmsford
   United Kingdom

   Phone: +44 1245 242194
   Email: chris.dearlove@baesystems.com
   URI:   http://www.baesystems.com/

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