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TMRID                                                    A. Wiethuechter
Internet-Draft                                                   S. Card
Intended status: Standards Track                           AX Enterprize
Expires: 30 April 2020                                      R. Moskowitz
                                                          HTT Consulting
                                                         28 October 2019


                     TM-RID Authentication Formats
                    draft-wiethuechter-tmrid-auth-02

Abstract

   This document describes how to include trust into the proposed ASTM
   Remote ID specification defined in WK65041 by the F38 Committee under
   a Broadcast Remote ID (RID) scenario.  It defines a few different
   message schemes (based on the authentication message) that can be
   used to assure past messages sent by a UA and also act as a assurance
   for UA trustworthiness in the absence of Internet connectivity at the
   receiving node.

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 https://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 30 April 2020.

Copyright Notice

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

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://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



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   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.  Terms and Definitions . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Requirements Terminology  . . . . . . . . . . . . . . . .   3
     2.2.  Definitions . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Background  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Problem Space And Document Focus  . . . . . . . . . . . .   4
     3.2.  Notation in the ASTM Remote ID Standard . . . . . . . . .   4
     3.3.  ASTM Authentication Message . . . . . . . . . . . . . . .   4
     3.4.  Thoughts on ASTM Authentication Message . . . . . . . . .   6
     3.5.  TM-RID Supporting Levels  . . . . . . . . . . . . . . . .   7
   4.  HIP Based Extensions to the ASTM Authentication
           Message . . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.1.  HIP Based Authentication Wrapper  . . . . . . . . . . . .   7
     4.2.  Signed Hash Lists . . . . . . . . . . . . . . . . . . . .   9
       4.2.1.  Hash Operation  . . . . . . . . . . . . . . . . . . .  12
       4.2.2.  Pseudo-blockchain Hashes  . . . . . . . . . . . . . .  12
       4.2.3.  Limitations . . . . . . . . . . . . . . . . . . . . .  12
     4.3.  HIP Based Offline Authentication  . . . . . . . . . . . .  13
   5.  Example Use Cases . . . . . . . . . . . . . . . . . . . . . .  14
     5.1.  Trusted Messages  . . . . . . . . . . . . . . . . . . . .  14
     5.2.  Wrapped Signed Hashes . . . . . . . . . . . . . . . . . .  16
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  19
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  19
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  19
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  19
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  19
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  19
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  20

1.  Introduction

   UA Systems (UAS) are usually in a volatile environment when it comes
   to communication.  UA are generally small with little computational
   (or flying) horsepower to carry standard communication equipment.
   This limits the mediums of communication to few viable options.

   The ASTM standard focuses on two ways of communicating to a UAS for
   RID: Broadcast and Network.

   This document will focus on adding trust to Broadcast RID in the
   current authentication message format, using the Host Identity




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   Protocol Version 2 (HIPv2) [RFC7401] Hierarchical HIT (HHIT)
   [I-D.moskowitz-hip-hierarchical-hit].

2.  Terms and Definitions

2.1.  Requirements 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 BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.2.  Definitions

   CAA  Civil Aeronautics Administration.  An example is the Federal
      Aviation Administration; (FAA) in the United States of America.

   C2  Command and Control.

   RID  Remote ID.

   HI  Host Identity.  The public key portion of an assymetric keypair
      from HIP.  In this document it is assume that the HI is a
      EdDSA25519 keypair.  This is supported by new crypto defined in
      [I-D.moskowitz-hip-new-crypto].

   HIT  Host Identity Tag. Defined in HIPv2 [RFC7401].

   HHIT  Hierarchical Host Identity Tag. Defined in
      [I-D.moskowitz-hip-hierarchical-hit].

   UA  Unmanned Aircraft.  In this document UAs are typically though of
      as drones of commerical or military variety.  This is a very
      strict definition which can be relaxed to include any and all
      aircraft that are unmanned.

   UAS (Unmanned Aircraft System)  Composed of Unmanned Aircraft and all
      required on-board subsystems, payload, control station, other
      required off-board subsystems, any required launch and recovery
      equipment, all required crew members, and command and control (C2)
      links between UA and the control station.

   USS (UAS Service Supplier)  USSs provide UTM services to support the
      UAS community, to connect Operators and other entities to enable
      information flow across the USS network, and to promote shared
      situational awareness among UTM participants.  (From FAA UTM
      ConOps V1, May 2018).



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3.  Background

3.1.  Problem Space And Document Focus

   The current draft standard for Remote ID (RID) does not, in any
   meaningful capacity, address the concerns of trust in the UA space
   with communication in the Broadcast RID environment.  This is a
   requirement that will need to be addressed eventually for various
   different parties that have a stake in the UA industry.

   The following subsections will provide reference to the ASTM standard
   for authentication messages and how their current limitations effect
   trust in the Broadcast RID envirorment.

3.2.  Notation in the ASTM Remote ID Standard

   As per the ASTM drafts [WK65041]:

   "Non-magnitude values, strings, or IDs that may be or may not be
   numerical (such as the Unique ID) shall be expressed in Network Byte
   Order which reads in a left to right, most significant byte (MSB) to
   least significant byte (LSB) order.  Magnitude values expressed as 16
   or 32 bit integers (such as Latitude, Longitude, Altitude, etc.)
   shall be expressed as "little endian", where the LSB is on the left
   and the MSB is on the right."

   In short; representation is network byte order but values are encoded
   little-endian.

3.3.  ASTM Authentication Message

   Page 0:
    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
   +---------------+---------------+---------------+---------------+
   |  Msg. Header  |   Page Count  |     Length    |               /
   +---------------+---------------+---------------+---------------+
   /                   Timestamp                   |               |
   +-----------------------------------------------+               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                Authentication Data / Signature                |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+




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   Page 1 - 4:
    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
   +---------------+-----------------------------------------------+
   |  Msg. Header  |                                               |
   +---------------+                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                 Authentication Data / Signature               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

   Msg. Header: (1 byte)
       On all pages. Contains two subfields.

          0     1     2     3     4     5     6     7
       +-----+-----+-----+-----+-----+-----+-----+-----+
       |      Page Number      |  Authentication Type  |
       +-----+-----+-----+-----+-----+-----+-----+-----+

       Authentication Type: (4 bits)
           Field denoting authentication message type based
           on the following table.

           Number   Type
           ------   ----
           0        None
           1        UAS ID Signature
           2        Operator ID Signature
           3        Message Set Signature
           4        Authentication Provided by Network RID
           5-9      Reserved for Specification
           A-F      Avalible for Private Use

       Page Number: (4 bits)
           Sequence number of current page in authentication
           message.

   Page Count: (1 byte)
       Only on page 0.
       Total number of pages this authentication message has.
       Max value of 5.




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          0     1     2     3     4     5     6     7
       +-----+-----+-----+-----+-----+-----+-----+-----+
       |       Page Count      |        RESERVED       |
       +-----+-----+-----+-----+-----+-----+-----+-----+

   Length: (1 byte)
       Only on page 0.
       Total length of Authentication Data / Signature in bytes.
       Value of 0 - 109.

   Timestamp: (4 bytes)
       Only on page 0.
       32 bit Unix timestamp in seconds since 00:00:00 01/01/2019.
       To relate back to standard Unix timestamp, add 1546300800 to
       base it on 00:00:00 01/01/1970.
       Max of 01/19/2087 @ 3:14am (UTC).

   Authentication Data / Signature: (109 bytes: 17+23*4)
       Opaque authentication data.

3.4.  Thoughts on ASTM Authentication Message

   The format proposed by the ASTM is designed with a few major
   considerations in mind, which the authors feel put significant
   limitations on the standard.

   The primary consideration (in this context) is the use of the
   Bluetooth 5.X Extended Frame format.  This method allows for a 255
   byte payload to be sent in what the ASTM refers to as an "atomic
   message".

   The idea in the ASTM is to include up to five standard ASTM Broadcast
   RID messages (each of which are 25 bytes) plus a single
   authentication message (5 pages of 25 bytes each) in an atomic
   message.  The reasoning is then the authentication message is for the
   entire atomic message pack.

   The authors have no issues with this proposed approach; given the
   restraints and current technologies the ASTM did a good job.
   However, by limiting the authentication message to ONLY five pages in
   the standard it ignores the possibility of other formatting options
   to be created and used.









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3.5.  TM-RID Supporting Levels

   This document is assuming that the first two levels of TM-RID
   (Identification and Authentication) are implemented.  This document
   serves as a expansion to these two levels, leveraging the abilities
   of the HHIT Registries [I-D.moskowitz-hip-hhit-registries] to its
   fullest potenional.

4.  HIP Based Extensions to the ASTM Authentication Message

   The following section describes various methods that HIP can help
   enable more trustworthy communication using the Authentication
   Message as the base.  Each diagram will show all 5 pages of the
   format filled out.

4.1.  HIP Based Authentication Wrapper

   Page 0:
    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
   +---------------+---------------+---------------+---------------+
   |  Msg. Header  |   Page Count  |     Length    |               /
   +---------------+---------------+---------------+---------------+
   /                   Timestamp                   |    RESERVED   |
   +-----------------------------------------------+---------------+
   |                                                               |
   |                                                               |
   |                                                               |
   |                             HHIT                              |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

   Page 1:
    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
   +---------------+-----------------------------------------------+
   |  Msg. Header  |                 Trust Timestamp               /
   +---------------+---------------+-------------------------------+
   /               |    RESERVED   |                               |
   +---------------+---------------+                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                         HHIT Signature                        |
   |                                                               |
   |                                                               |



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   |                                                               |
   +---------------------------------------------------------------+

   Page 2:
    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
   +---------------+-----------------------------------------------+
   |  Msg. Header  |                                               |
   +---------------+                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                         HHIT Signature                        |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

   Page 3:
    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
   +---------------+-----------------------------------------------+
   |  Msg. Header  |                                               |
   +---------------+                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                         HHIT Signature                        |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

   Page 4:
    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
   +---------------+-----------------------------------------------+
   |  Msg. Header  |                                               |
   +---------------+                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                            Payload                            |



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   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

   HHIT: (16 bytes)
       HHIT using the EdDSA25519 HI.

   Trust Timestamp: (4 bytes)
       Timestamp denoting a future time to trust message to.

   HHIT Signature: (64 bytes)
       Signature of payload using the EdDSA25519 keypair.
       Spread across 3 pages.

   Payload: (0 to 23/25 bytes)
       Opaque payload data that has been used in signing.
       This can be increased to 25 by removing padding RESERVED
       sections.

   This format is a way to authenticate a given UA using Level 1 and
   Level 2 of the TM-RID architecture.

4.2.  Signed Hash Lists

   Page 0:
    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
   +---------------+---------------+---------------+---------------+
   |  Msg. Header  |   Page Count  |     Length    |               /
   +---------------+---------------+---------------+---------------+
   /                   Timestamp                   | H-Alg | H-Len |
   +---------------------------------------------------------------+
   |                Hash of Previous Auth. Message                 |
   +---------------------------------------------------------------+
   |                Hash of Current Auth. Message                  |
   +---------------------------------------------------------------+
   |                          Message Hash                         |
   +---------------------------------------------------------------+
   |                          Message Hash                         |
   +---------------------------------------------------------------+

   DataPage 1:
    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
   +---------------+---------------+-------------------------------+
   |  Msg. Header  | H-Alg | H-Len |            RESERVED           |



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   +---------------+---------------+-------------------------------+
   |                          Message Hash                         |
   +---------------------------------------------------------------+
   |                          Message Hash                         |
   +---------------------------------------------------------------+
   |                          Message Hash                         |
   +---------------------------------------------------------------+
   |                          Message Hash                         |
   +---------------------------------------------------------------+
   |                          Message Hash                         |
   +---------------------------------------------------------------+

   Page 2:
    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
   +---------------+---------------+-------------------------------+
   |  Msg. Header  |    RESERVED   |       Signature Length        |
   +---------------+---------------+-------------------------------+
   |       Signature Algorithm     |                               |
   +-------------------------------+                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                         HHIT Signature                        |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

   Page 3:
    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
   +---------------+-----------------------------------------------+
   |  Msg. Header  |                                               |
   +---------------+                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                         HHIT Signature                        |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

   Page 4:
    0                   1                   2                   3



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    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
   +---------------+-----------------------------------------------+
   |  Msg. Header  |                                               |
   +---------------+                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                         HHIT Signature                        |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

   H-Alg, H-Len: (4 bits), (4 bits)
       These are fields for relaying information of the Hash
       algorithm used for the messages and the Hash length (in octets).
       For this example of the format a length of 4 bytes is
       used.

       H-Alg       Values
       -----       ------
       RESERVED    0
       cSHAKE128   1 [sp800-185] (RECOMMENDED)

   Hash of Previous Auth. Message: (4 bytes)
       A hash of the previously sent Authentication message.

   Hash of Current Auth. Message: (4 bytes)
       A hash of the current Authentication message.

   Message Hash: (4 bytes)
       A hash of a previously sent message.

   Signature Length: (2 bytes)
       Length of signature in octets, excluding Length, and Padding

   Signature Algorithm: (2 bytes)
       Self explanatory.

   HHIT Signature: (64 bytes)
       EdDSA25519 signature using an EdDSA25519-based HHIT from HIP.
       Spread across 3 pages.

   This format is designed to provide provenance to Broadcast RID
   messages sent by a give UAS.  It should be noted that the HHIT is not




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   provided in the format like others - instead it must be obtained via
   the Basic ID Message.

   By hashing previously sent messages and signing them we gain trust in
   the UAS's previous reports.  An observer who has been listening for
   any length of time can hash received messages and cross check against
   listed hashes.  The signature is signed across the list of hashes.

4.2.1.  Hash Operation

   With cSHAKE128 NIST SP 800-185 [NIST.SP.800-185], the hash is
   computed as follows:

        cSHAKE128(MAC|Message, 8*H-Len, "", "RemoteID Auth Hash")

   The message MAC is prepended to the message, as the MAC is the only
   information that links a UA's messages as from a specific UA.

4.2.2.  Pseudo-blockchain Hashes

   Two special hashes are included; a previous authentication hash,
   which links to the previous signed hash list message, as well as a
   current hash.  This gives a pseudo-blockchain provenance to the
   authentication message that could be traced back if the observer was
   present for extended periods of time.

   In regards to the creation and use of the current authentication hash
   field:

      During creation and signing of this message format this field MUST
      be set to 0.  So the signature will be based on this field being
      0, as well as its own hash.  It is an open question of if we
      compute the hash, then sign or sign then compute.

      There a few different ways to cycle this message.  We can "roll
      up" the hash of 'current' to 'previous' when needed or to
      completely recompute the hash.  This mostly depends on the
      previous note.

4.2.3.  Limitations

   With the current format defined by ASTM only 7 messages can be hashed
   reasonably in the above format.  RESERVED padding, the Signature
   Algorithm, Signature Length and redundant H-Alg, H-Len fields (of
   page 1) could be removed.  This would increase the total list of
   hashes to 9 while losing word alignment of the hashes in each page.





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   To address this problem properly the authors feel that the
   Authentication Messages needs to have a max bound of 10 pages,
   instead of 5.

4.3.  HIP Based Offline Authentication

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                            DEV HHIT                           |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            TIMESTAMP                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                            DEV HHIT                           |
   |                              SIG                              |
   .                                                               .
   .                                                               .
   .                                                               .
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                              DEV HI                           |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         AUTH TIMESTAMP                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                           AUTH HHIT                           |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                            AUTH                               |
   |                              SIG                              |
   .                                                               .
   .                                                               .
   .                                                               .
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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   /                            PAYLOAD                            /
   /                                                               /
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   DEV HHIT       16 byte Dev HHIT of EdDSA25519 HI
   TIMESTAMP      4 byte packet trust until timestamp
   DEV HHIT SIG   64 byte Signature of whole packet
   DEV HI         32 byte Device HI of EdDSA25519 HI
   AUTH TIMESTAMP 4 byte Dev HHIT trust until timestamp
   AUTH HHIT      16 byte Authorizer's HHIT of EdDSA25519 HI
   AUTH SIG       64 byte Signature of Device HHIT-HI
   PAYLOAD        0 to n bytes of payload
   Length         200 + n bytes

   This specific format does not currently fit within the ASTM
   specification.  Requiring a minimum of 200 bytes, this would require
   the Authentication Message to have 10 pages, instead of the current 5
   page limit.

   What this will grant, if attainable in future revisions of the ASTM
   specification, is the ability to authenticate UA information when the
   receiving device of the observer (e.g. a smartphone with a dedicated
   RID application) has no Internet service (e.g.  LTE signal).

   By including the device HI along with a signature from the registry
   the UA is under, we can assert trust of a given drone without
   requiring the need for immediate reverse lookups online.

5.  Example Use Cases

   This section introduces potentional use cases of the HIP based
   extensions to the ASTM standard authentication message.

5.1.  Trusted Messages

   Using the HIP Based Authentication Wrapper any single Broadcast RID
   message defined by ASTM can become what the authors refer to as a
   "Trusted Message".

   One specific use case that is useful in the UAS RID space is the
   creation of a "Trusted Vector Message".  By placing a previous [or
   new] vector message into the Payload section of this format a
   verifiable broadcast can be created.

   Due to being signed this creates an authentic vector that is hard to
   spoof, which can confirm flight paths in near real time.





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   The figure below is a example of a "Trusted Vector Message".  Note
   that the padding (RESERVED) byte are now gone.  The "Trust Timestamp"
   and "Vector Message" fields now span multiple pages instead of being
   aligned to pages.

   Page 0:
    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
   +---------------+---------------+---------------+---------------+
   |  Msg. Header  |   Page Count  |     Length    |               /
   +---------------+---------------+---------------+---------------+
   /                   Timestamp                   |               |
   +-----------------------------------------------+               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                             HHIT                              |
   |                                                               |
   |                                               +---------------+
   |                                               |               /
   +-----------------------------------------------+---------------+

   Page 1:
    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
   +---------------+-----------------------------------------------+
   |  Msg. Header  /                 Trust Timestamp               |
   +---------------+-----------------------------------------------+
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                         HHIT Signature                        |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

   Page 2:
    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
   +---------------+-----------------------------------------------+
   |  Msg. Header  |                                               |
   +---------------+                                               |
   |                                                               |
   |                                                               |
   |                                                               |



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   |                                                               |
   |                         HHIT Signature                        |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

   Page 3:
    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
   +---------------+-----------------------------------------------+
   |  Msg. Header  |                                               |
   +---------------+                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                         HHIT Signature                        |
   |                                                               |
   |                                                               |
   |                                                               |
   |                               +-------------------------------+
   |                               |        Vector Message         |
   +-------------------------------+-------------------------------+

   Page 4:
    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
   +---------------+-----------------------------------------------+
   |  Msg. Header  |                                               |
   +---------------+                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                         Vector Message                        |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

5.2.  Wrapped Signed Hashes

   Using the HIP Based Authentication Wrapper a [short] list of hashes
   can be signed.  These hashes are of previous individual RID messages.





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   This follows the format of the Signed Hash List, excluding the
   psuedo-blockchain hashes and various other fields enabling it to fit
   within the 23 byte limit of the final page.

   To the authors, this format has limited use due to numerous concerns
   of replay attacks.  It is suggested to instead use the full Signed
   Hash List format.

   Page 0:
    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
   +---------------+---------------+---------------+---------------+
   |  Msg. Header  |   Page Count  |     Length    |               /
   +---------------+---------------+---------------+---------------+
   /                   Timestamp                   |    RESERVED   |
   +-----------------------------------------------+---------------+
   |                                                               |
   |                                                               |
   |                                                               |
   |                             HHIT                              |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

   Page 1:
    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
   +---------------+-----------------------------------------------+
   |  Msg. Header  |                 Trust Timestamp               /
   +---------------+---------------+-------------------------------+
   /               |    RESERVED   |                               |
   +---------------+---------------+                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                         HHIT Signature                        |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

   Page 2:
    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
   +---------------+-----------------------------------------------+
   |  Msg. Header  |                                               |
   +---------------+                                               |



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   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                         HHIT Signature                        |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

   Page 3:
    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
   +---------------+-----------------------------------------------+
   |  Msg. Header  |                                               |
   +---------------+                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   |                         HHIT Signature                        |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   +---------------------------------------------------------------+

   Page 4:
    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
   +---------------+---------------+-------------------------------+
   |  Msg. Header  | H-Alg | H-Len |            RESERVED           |
   +---------------+---------------+-------------------------------+
   |                          Message Hash                         |
   +---------------------------------------------------------------+
   |                          Message Hash                         |
   +---------------------------------------------------------------+
   |                          Message Hash                         |
   +---------------------------------------------------------------+
   |                          Message Hash                         |
   +---------------------------------------------------------------+
   |                          Message Hash                         |
   +---------------------------------------------------------------+







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6.  IANA Considerations

   TBD

7.  Security Considerations

   TBD

8.  Acknowledgments

   TBD

9.  References

9.1.  Normative References

   [NIST.SP.800-185]
              Kelsey, J., Change, S., and R. Perlner, "SHA-3 derived
              functions: cSHAKE, KMAC, TupleHash and ParallelHash",
              DOI 10.6028/nist.sp.800-185, National Institute of
              Standards and Technology report, December 2016,
              <https://doi.org/10.6028/nist.sp.800-185>.

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

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

9.2.  Informative References

   [I-D.moskowitz-hip-hhit-registries]
              Moskowitz, R., Card, S., and A. Wiethuechter,
              "Hierarchical HIT Registries", draft-moskowitz-hip-hhit-
              registries-01 (work in progress), 17 October 2019,
              <http://www.ietf.org/internet-drafts/draft-moskowitz-hip-
              hhit-registries-01.txt>.

   [I-D.moskowitz-hip-hierarchical-hit]
              Moskowitz, R., Card, S., and A. Wiethuechter,
              "Hierarchical HITs for HIPv2", draft-moskowitz-hip-
              hierarchical-hit-02 (work in progress), 17 October 2019,
              <http://www.ietf.org/internet-drafts/draft-moskowitz-hip-
              hierarchical-hit-02.txt>.




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   [I-D.moskowitz-hip-new-crypto]
              Moskowitz, R., Card, S., and A. Wiethuechter, "New
              Cryptographic Algorithms for HIP", draft-moskowitz-hip-
              new-crypto-02 (work in progress), 3 October 2019,
              <http://www.ietf.org/internet-drafts/draft-moskowitz-hip-
              new-crypto-02.txt>.

   [RFC7401]  Moskowitz, R., Ed., Heer, T., Jokela, P., and T.
              Henderson, "Host Identity Protocol Version 2 (HIPv2)",
              RFC 7401, DOI 10.17487/RFC7401, April 2015,
              <https://www.rfc-editor.org/info/rfc7401>.

   [WK65041]  ASTM, "Standard Specification for Remote ID and Tracking",
              September 2019.

Authors' Addresses

   Adam Wiethuechter
   AX Enterprize
   4947 Commercial Drive
   Yorkville, NY 13495
   United States of America

   Email: adam.wiethuechter@axenterprize.com


   Stuart W. Card
   AX Enterprize
   4947 Commercial Drive
   Yorkville, NY 13495
   United States of America

   Email: stu.card@axenterprize.com


   Robert Moskowitz
   HTT Consulting
   0000
   Oak Park, MI 48237
   United States of America

   Email: rgm@labs.htt-consult.com









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