Skip to main content

DRIP Entity Tag (DET) Identity Management Architecture
draft-ietf-drip-registries-13

The information below is for an old version of the document.
Document Type
This is an older version of an Internet-Draft whose latest revision state is "Active".
Authors Adam Wiethuechter , Jim Reid
Last updated 2023-12-01 (Latest revision 2023-09-18)
Replaces draft-wiethuechter-drip-registries
RFC stream Internet Engineering Task Force (IETF)
Formats
Reviews
OPSDIR Early review (of -09) by Joel Jaeggli Partially completed Has issues
Additional resources Mailing list discussion
Stream WG state WG Document
Associated WG milestones
Sep 2020
Solution space documents adopted by the WG
Mar 2024
Submit DRIP Registries to the IESG
Document shepherd Daniel Migault
IESG IESG state I-D Exists
Consensus boilerplate Yes
Telechat date (None)
Responsible AD (None)
Send notices to daniel.migault@ericsson.com
draft-ietf-drip-registries-13
drip Working Group                                  A. Wiethuechter, Ed.
Internet-Draft                                        AX Enterprize, LLC
Intended status: Standards Track                                 J. Reid
Expires: 21 March 2024                                          RTFM llp
                                                       18 September 2023

         DRIP Entity Tag (DET) Identity Management Architecture
                     draft-ietf-drip-registries-13

Abstract

   This document describes the high level architecture for the
   registration and discovery of DRIP Entity Tags (DETs) using DNS.
   Discovery of DETs and their artifacts are through DRIP specific DNS
   structures and standard DNS methods.  A general overview of the
   interfaces required between involved components is described in this
   document with future supporting documents giving technical
   specifications.

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 21 March 2024.

Copyright Notice

   Copyright (c) 2023 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Wiethuechter & Reid       Expires 21 March 2024                 [Page 1]
Internet-Draft             DETIM Architecture             September 2023

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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Abstract Process and Reasoning  . . . . . . . . . . . . . . .   5
     2.1.  Supported Scenarios . . . . . . . . . . . . . . . . . . .   5
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   6
     3.1.  Required Terminology  . . . . . . . . . . . . . . . . . .   6
     3.2.  Additional Definitions  . . . . . . . . . . . . . . . . .   6
     3.3.  Text Conventions  . . . . . . . . . . . . . . . . . . . .   7
   4.  DIME Roles  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.1.  Apex  . . . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.2.  Registered Assigning Authority (RAA)  . . . . . . . . . .   9
       4.2.1.  ISO 3166-1 Numeric Nations (INN)  . . . . . . . . . .   9
       4.2.2.  Manufacturer Code Authority (MCA) . . . . . . . . . .   9
     4.3.  Hierarchial HIT Domain Authority (HDA)  . . . . . . . . .  10
       4.3.1.  Manufacturer Unmanned Aircraft Authority (MAA)  . . .  11
   5.  DIME Architecture . . . . . . . . . . . . . . . . . . . . . .  11
     5.1.  DRIP Provisioning Agent (DPA) . . . . . . . . . . . . . .  12
     5.2.  Registry  . . . . . . . . . . . . . . . . . . . . . . . .  13
     5.3.  Name Server (NS)  . . . . . . . . . . . . . . . . . . . .  14
     5.4.  DRIP Information Agent (DIA)  . . . . . . . . . . . . . .  15
     5.5.  Registration Data Directory Service (RDDS)  . . . . . . .  16
   6.  Registration/Provisioning Process . . . . . . . . . . . . . .  17
     6.1.  Serial Number . . . . . . . . . . . . . . . . . . . . . .  17
       6.1.1.  Serial Method 1 . . . . . . . . . . . . . . . . . . .  18
       6.1.2.  Serial Method 2 . . . . . . . . . . . . . . . . . . .  18
       6.1.3.  Serial Method 3 . . . . . . . . . . . . . . . . . . .  19
       6.1.4.  Serial Method 4 . . . . . . . . . . . . . . . . . . .  20
     6.2.  Operator  . . . . . . . . . . . . . . . . . . . . . . . .  21
     6.3.  Session ID  . . . . . . . . . . . . . . . . . . . . . . .  22
       6.3.1.  UA Based Session ID . . . . . . . . . . . . . . . . .  24
       6.3.2.  UAS Based Session ID  . . . . . . . . . . . . . . . .  24
     6.4.  Child DIME  . . . . . . . . . . . . . . . . . . . . . . .  25
   7.  Differentiated Access Process . . . . . . . . . . . . . . . .  26
   8.  DRIP in the Domain Name System  . . . . . . . . . . . . . . .  27
     8.1.  DRIP Entity Tags  . . . . . . . . . . . . . . . . . . . .  28
       8.1.1.  DET Resource Record . . . . . . . . . . . . . . . . .  28
     8.2.  Serial Numbers & Other UAS ID Types . . . . . . . . . . .  29
   9.  Endorsements  . . . . . . . . . . . . . . . . . . . . . . . .  30

Wiethuechter & Reid       Expires 21 March 2024                 [Page 2]
Internet-Draft             DETIM Architecture             September 2023

     9.1.  Endorsement Structure . . . . . . . . . . . . . . . . . .  30
       9.1.1.  Scope . . . . . . . . . . . . . . . . . . . . . . . .  31
       9.1.2.  Evidence  . . . . . . . . . . . . . . . . . . . . . .  31
       9.1.3.  Identity  . . . . . . . . . . . . . . . . . . . . . .  31
       9.1.4.  Signature . . . . . . . . . . . . . . . . . . . . . .  32
   10. X.509 Certificates  . . . . . . . . . . . . . . . . . . . . .  32
     10.1.  Certificate Policy and Certificate Stores  . . . . . . .  32
     10.2.  Certificate Management . . . . . . . . . . . . . . . . .  33
     10.3.  Examples . . . . . . . . . . . . . . . . . . . . . . . .  34
     10.4.  Alternative Certificate Encoding . . . . . . . . . . . .  34
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  34
     11.1.  Delegation of Nibble Reversed IPv6 Prefix  . . . . . . .  34
     11.2.  IANA DRIP Registry . . . . . . . . . . . . . . . . . . .  35
       11.2.1.  Aircraft Information Registry  . . . . . . . . . . .  35
       11.2.2.  Endorsement Fields . . . . . . . . . . . . . . . . .  36
   12. Security Considerations . . . . . . . . . . . . . . . . . . .  37
     12.1.  Key Rollover & Federation  . . . . . . . . . . . . . . .  37
     12.2.  DET Generation . . . . . . . . . . . . . . . . . . . . .  37
   13. Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  38
   14. References  . . . . . . . . . . . . . . . . . . . . . . . . .  38
     14.1.  Normative References . . . . . . . . . . . . . . . . . .  38
     14.2.  Informative References . . . . . . . . . . . . . . . . .  39
   Appendix A.  DRIP Fully Qualified Domain Names  . . . . . . . . .  41
     A.1.  DRIP Entity Tag . . . . . . . . . . . . . . . . . . . . .  41
     A.2.  UAS Serial Number . . . . . . . . . . . . . . . . . . . .  41
   Appendix B.  DRIP Endorsements for UAS  . . . . . . . . . . . . .  41
     B.1.  Generic Endorsement . . . . . . . . . . . . . . . . . . .  41
     B.2.  Self Endorsement  . . . . . . . . . . . . . . . . . . . .  42
     B.3.  Broadcast Endorsement . . . . . . . . . . . . . . . . . .  43
   Appendix C.  DNS Examples . . . . . . . . . . . . . . . . . . . .  46
     C.1.  Serial Method 1 . . . . . . . . . . . . . . . . . . . . .  46
     C.2.  Serial Method 2 . . . . . . . . . . . . . . . . . . . . .  46
     C.3.  Serial Method 3 . . . . . . . . . . . . . . . . . . . . .  46
     C.4.  Serial Method 4 . . . . . . . . . . . . . . . . . . . . .  46
     C.5.  Operator  . . . . . . . . . . . . . . . . . . . . . . . .  46
     C.6.  Session ID  . . . . . . . . . . . . . . . . . . . . . . .  46
     C.7.  Child DIME  . . . . . . . . . . . . . . . . . . . . . . .  47
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  47

1.  Introduction

   Registries are fundamental to Unmanned Aircraft System (UAS) Remote
   ID (RID).  Only very limited operational information can be
   Broadcast, but extended information is sometimes needed.  The most
   essential element of information is the UAS ID, the unique key for
   lookup of extended information in relevant registries (see Figure 4
   of [RFC9434]).

Wiethuechter & Reid       Expires 21 March 2024                 [Page 3]
Internet-Draft             DETIM Architecture             September 2023

   While it is expected that DRIP Identity Management Entity (DIME)
   functions will be integrated with UAS Service Suppliers (USS)
   (Appendix A.2 of [RFC9434]), who will provide DIME-like functions is
   not yet determined in most, and is expected to vary between,
   jurisdictions.  However this evolves, the essential DIME-like
   functions (including the management of identifiers (such as the DRIP
   Entity Tag (DET))) are expected to remain the same, so are specified
   herein.

   While most data to be sent via Broadcast RID (Section 1.2.1 of
   [RFC9434]) or Network RID (Section 1.2.2 of [RFC9434]) is public,
   much of the extended information in registries will be private.  As
   discussed in Section 7 of [RFC9434], Authentication, Attestation,
   Authorization, Access Control, Accounting, Attribution, and Audit
   (AAA) for registries is essential, not just to ensure that access is
   granted only to strongly authenticated, duly authorized parties, but
   also to support subsequent attribution of any leaks, audit of who
   accessed information when and for what purpose.  As specific AAA
   requirements will vary by jurisdictional regulation, provider
   choices, customer demand, etc., they are left to specification in
   policies, which should be human readable to facilitate analysis and
   discussion, and machine readable to enable automated enforcement,
   using a language amenable to both (e.g., eXtensible Access Control
   Markup Language (XACML)).

   The intent of the access control requirements on registries is to
   ensure that no member of the public would be hindered from accessing
   public information, while only duly authorized parties would be
   enabled to access private information.  Mitigation of Denial of
   Service (DoS) attacks and refusal to allow database mass scraping
   would be based on those behavior, not on identity or role of the
   party submitting the query per se, but querant identity information
   might be gathered (by security systems protecting DRIP
   implementations) on such misbehavior.

   Registration under DRIP is vital to manage the inevitable collisions
   in the hash portion of the DET (Section 9.5 of [RFC9374]).  Forgery
   of a DET is still possible, but including it as a part of a public
   registration mitigates this risk.

   This document creates the DET registration and discovery ecosystem.
   This includes all components in the ecosystem (e.g., Unmanned
   Aircraft (UA), Registered Assigning Authority (RAA), Hierarchical HIT
   Domain Authority (HDA), Ground Control Station (GCS), and USS).

   This document uses the Concise Data Definition Language (CDDL)
   [RFC8610] for describing the registration data.

Wiethuechter & Reid       Expires 21 March 2024                 [Page 4]
Internet-Draft             DETIM Architecture             September 2023

2.  Abstract Process and Reasoning

   In DRIP each entity (DIME, Operator, UA, etc.) is expected to
   generate a DET [RFC9374] on the local device their key is expected to
   be used.  These are registered with a Public Information Registry
   (e.g.  DNS) within the hierarchy along with whatever data is required
   by the cognizant CAA and the DIME.  Any Personally Identifiable
   Information (PII) is stored in a Private Information Registry
   protected through industry practice AAA or stronger.  In response,
   the entity will obtain an endorsement from the DIME proving such
   registration.

   Manufacturers that wish to participate in DRIP should not only
   support DRIP as a Session ID type for their aircraft but could also
   generate a DET then encode it as a Serial Number (Section 4.2 of
   [RFC9374]).  This would allow aircraft under CAA mandates to fly only
   ID Type 1 (Serial Number) could still use DRIP and most of its
   benefits.  Even if DRIP is not supported for Serial Numbers by a
   Manufacturer it is hoped that they would still run a DIME to store
   their Serial Numbers and allow look ups for generic model
   information.  This look up could be especially helpful in UTM for
   Situational Awareness when an aircraft flying with a Serial Number is
   detected and allow for an aircraft profile to be displayed.

   Operators are registered with a number of registries or their
   regional RAA.  This acts as a verification check when a user performs
   other registration operations; such as provisioning an aircraft with
   a new Session ID.  It is an open question if an Operator registers to
   their CAA (the RAA's direct HDA) or multiple USS's (HDA's).  PII of
   the Operator would vary based on the CAA they are under and the DIME.

   Finally, aircraft that support using a DET would provision per flight
   to a USS, proposing a DET to the DIME to generate a binding between
   the aircraft (Session ID, Serial Number, and Operational Intent),
   operator and DIME.  The aircraft then follows [drip-auth] to meet
   various requirements from [RFC9153] during a flight.

2.1.  Supported Scenarios

      Author Note: with the proposal to remove solving the issue of
      putting Serial Numbers into DNS from this document, this section
      most likely is removed or merged with another.  The only point to
      merge is #6.

   1.  UA using manufacturer generated Serial Number for UAS ID.  No
       additional information provided.

Wiethuechter & Reid       Expires 21 March 2024                 [Page 5]
Internet-Draft             DETIM Architecture             September 2023

   2.  UA using manufacturer generated Serial Number for UAS ID.
       Manufacturer using a DIME.  Manufacturer MUST provided pointer to
       additional information via DNS (even if null).

   3.  UA using manufacturer generated Serial Number which is mapped to
       a DET by manufacturer for UAS ID.  UA using manufacturer
       generated DET for Authentication.  Manufacturer using a DIME.
       DIME MUST place public DET information into DNS (i.e.  HI).  DIME
       MUST provide mapping of Serial Number to DET in DNS.
       Manufacturer MUST provide pointer to additional information via
       DNS (even if null).

   4.  UA using manufacturer generated DRIP enhanced Serial Number for
       UAS ID.  UA using manufacturer generated DET for Authentication.
       Manufacturer using a DIME.  DIME MUST place public information
       into DNS (i.e.  HI) - either directly or as a mapping to a DET.
       DIME MUST provide pointer to additional information via DNS (even
       if null).

   5.  UA using manufacturer generated Serial Number for UAS ID.  UA
       using user generated DET for Authentication.  User uses DIME with
       capability to publicly map Serial Number to a DET (via a USS).
       DIME MUST place public DET information into DNS (i.e.  HI).  DIME
       MUST provide mapping of Serial Number to DET in DNS.  DIME MUST
       provide pointer to additional information via DNS (even if null).

   6.  UA provisioned with DET (i.e.  Session ID) with a DIME (via a
       USS) for UAS ID and Authentication.  DIME MUST place public DET
       information into DNS (i.e.  HI).  DIME MUST NOT (unless required)
       provide mapping of DET to Serial Number in DNS.  USS MUST provide
       pointer to additional information via DNS (even if null).

3.  Terminology

3.1.  Required 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.

3.2.  Additional Definitions

   This document makes use of the terms (PII, USS, etc.) defined in
   [RFC9153].  Other terms (DIME, Endorsement, etc.) are from [RFC9434],
   while others (RAA, HDA, etc.) are from [RFC9374].

Wiethuechter & Reid       Expires 21 March 2024                 [Page 6]
Internet-Draft             DETIM Architecture             September 2023

3.3.  Text Conventions

   When talking about a DIME in documents it should be referred to as
   the role it is serving.  For example a CAA level DIME running
   services both as an RAA (its primary role in the hierarchy) and as an
   HDA (optionally) would be be referred to "RAA" when performing its
   RAA duties and "HDA" when performing its HDA duties.  The rest of the
   document will follow this convention unless verbosity or clarity is
   needed.

4.  DIME Roles

   [RFC9434] defines the DRIP Identity Management Entity (DIME) as an
   entity that vets Claims and/or Evidence from a registrant and
   delivers, to successful registrations, Endorsements and/or
   Certificates in response.  The DIME encompasses various logical
   components and can be classified to serve a number of different
   roles, which are detailed in the following subsections.  The general
   hierarchy of these initial roles (some highly specialized and
   predetermined for the UAS use case) are illustrated in Figure 1.

                          +----------+
                          |   Apex   o--------.
                          +-o------o-+        |
                            |      |          |
          ******************|******|**********|******************
                            |      |          |
                      +-----o-+  +-o-----+  +-o-----+
          RAAs        |  MCA  |  |  INN  |  |  RAA  |
                      +---o---+  +---o---+  +---o---+
                          |          |          |
          ****************|**********|**********|****************
                          |          |          |
                      +---o---+  +---o---+  +---o---+
          HDAs        |  MAA  |  |  HDA  |  |  HDA  |
                      +-------+  +-------+  +-------+

                     Figure 1: DIME Roles and Hierarchy

4.1.  Apex

   The Apex is a special DIME role that holds the values of RAA=0-3 and
   HDA=0.  It serves as the branch point from the larger DNS system in
   which DETs are defined.  The Apex is the owner of the IPv6 prefix
   portion of the DET associated with it (2001:30/28) which is assigned
   by IANA from the special IPv6 address space for ORCHIDs.

Wiethuechter & Reid       Expires 21 March 2024                 [Page 7]
Internet-Draft             DETIM Architecture             September 2023

   The Apex manages all delegations and allocations of the DET's RAA to
   various parties.  Allocations of RAAs SHOULD be done in contiguous
   groups of 4.

   +===================+=================+=============================+
   | RAA Decimal Range | RAA Hex Range   | Status                      |
   +===================+=================+=============================+
   | 0 - 3             | 0x0000 -        | Apex                        |
   |                   | 0x0003          |                             |
   +-------------------+-----------------+-----------------------------+
   | 4 - 3999          | 0x0004 -        | ISO 3166-1 Countries        |
   |                   | 0x0F9F          | (Section 4.2.1)             |
   +-------------------+-----------------+-----------------------------+
   | 4000 - 4095       | 0x0FA0 -        | Manufacturer Code           |
   |                   | 0x0FFF          | Authorities (Section 4.2.2) |
   +-------------------+-----------------+-----------------------------+
   | 4096 - 16375      | 0x1000 -        | Reserved                    |
   |                   | 0x3FFF          |                             |
   +-------------------+-----------------+-----------------------------+
   | 16376 - 16383     | 0x3FF8 -        | DRIP WG Experimental Use    |
   |                   | 0x3FFF          |                             |
   +-------------------+-----------------+-----------------------------+

                                  Table 1

      Note: that the first column of this table is _decimal_ values
      *not* _hexadecimal_.

   RAA values of 0 (0x0000) to 3 (0x0003) are reserved to the Apex
   exclusively.

   The Experimental range of 16376 (0x3FF8) to 16383 (0x3FFF), eight (8)
   RAAs, is allocated to the DRIP working group itself. 16376 to 16379
   are setup by DRIP experts to act as RAAs for potential HDA users to
   test against.  RAA 16376 is already "in use" with driptesting.org.
   16379 is to be setup as an RAA to act as a MCA Section 4.2.2 for UAS
   manufacturers to test their HDAs against and have their Manufacturer
   Code properly managed.  The rest of the range (16380 to 16383) are
   reserved to be allocate by the DRIP experts to agencies that wish to
   test being an RAA.

Wiethuechter & Reid       Expires 21 March 2024                 [Page 8]
Internet-Draft             DETIM Architecture             September 2023

4.2.  Registered Assigning Authority (RAA)

   RAA's are the upper hierarchy in DRIP (denoted by a 14-bit field,
   i.e. 16,384 RAAs, of an DET).  An RAA is a business or organization
   that manages a DIME of HDAs (Section 4.3).  Most are contemplated to
   be Civil Aviation Authorities (CAA), such as the Federal Aviation
   Authority (FAA), that then delegate HDAs to manage their National Air
   Space (NAS).  This is does not preclude other entities to operate an
   RAA if the Apex allows it.

   An RAA must provide a set of services to allocate HDAs to
   organizations.  It must have a public policy on what is necessary to
   obtain an HDA.  It must maintain a DNS zone minimally for discovering
   HID RVS servers.  All RAA's have a single reserved HDA value: 0
   (0x0000) for itself to support various functions or services.  Other
   HDA values can be allocated or reserved per RAA policy.

4.2.1.  ISO 3166-1 Numeric Nations (INN)

   The RAA range of 4 (0x0004) to 3999 (0x0F9F) are reserved for CAAs
   using the ISO 3166-1 Numeric Nation Code.  The RAA can be derived
   from the ISO 3166-1 numeric code by multiplying the value by 4 (i.e.
   raa_code = iso_code * 4).  Four contiguous values are used in a
   single allocation.  The inverse (RAA to ISO) works out as: iso_code =
   floor(raa_code / 4).

   As an example the United States has an ISO 3166-1 Numeric Code of
   840.  This derives the following RAAs: 3360, 3361, 3362 and 3363.

   It should be noted that the range of codes from 900 to 999 are
   defined as "user assigned code elements" without specific claimant
   predefined in the RAA space.  Withdrawn and other special codes also
   do not have predetermined claimants.

   How a CAA handles their 4 allocations are out of scope of this
   document.  Control of these values are expected to be claimed by
   their respective owner.  How a claim is vetted and validated is out
   of scope of this document.  Protection against fraudulent claims of
   one of these values is out of scope for this document.

      Note: A single entity may control more than one NAS (for example
      LU and BE being covered by Skeyes.be) and would manage two
      allocation spaces.  How this is claimed and handled is out of
      scope for this document.

4.2.2.  Manufacturer Code Authority (MCA)

Wiethuechter & Reid       Expires 21 March 2024                 [Page 9]
Internet-Draft             DETIM Architecture             September 2023

      Author Note: with the proposal to remove solving the issue of
      putting Serial Numbers into DNS from this document, this section
      is either moved to a new document or left here.

   An RAA-level DIME that hands out HDA values to participating
   Manufacturer's that hold an Manufacturer Code used in [CTA2063A] that
   is issued by ICAO.

   To manage the large Manufacturer Code space (34 character set; 4
   characters; 1,336,336 possible codes) a range of RAA values are set
   aside for the use case.  These are the RAA values of 4000 (0x0FA0) up
   to 4095 (0x0FFF).  This allows a single HDA for each Manufacturer
   Code.

   See Section 4.3.1 for the HDA allocation of Manufacturer Codes under
   these RAAs.

      Note: the upper RAAs in the range (4083 to 4095) are not used but
      are left reserved in this space for future action if required.

4.3.  Hierarchial HIT Domain Authority (HDA)

   An HDA may be an USS, ISP, or any third party that takes on the
   business to register the actual entities that need DETs.  This
   includes, but is not limited to UA, GCS, UAS Operators and
   infrastructure (such as Supplemental Data Service Providers).  It
   should also provide needed UAS services including those required for
   HIP-enabled devices (e.g.  RVS).

   A primary function of HDAs for DRIP, in the context of UAS RID is the
   binding between a UAS Session ID (for DRIP the DET) and the UA Serial
   Number.  The Serial Number MUST have its access protected to allow
   only authorized parties to obtain it.  The Serial Number MUST be
   protected in a way only the authorized party can decrypt.  As part of
   the UTM system HDAs can also hold a binding between a UAS ID (Serial
   Number or Session ID) and an Operational Intent.  They may either be
   a direct logical part of a UAS Service Supplier (USS) or be a UTM
   wide service to USS's.

   The HDA is a 14-bit field (16,384 HDAs per RAA) of a DET assigned by
   an RAA.  An HDA should maintain a set of RVS servers for UAS clients
   that may use HIP.  How this is done and scales to the potentially
   millions of customers are outside the scope of this document.  This
   service should be discoverable through the DNS zone maintained by the
   HDA's RAA.

Wiethuechter & Reid       Expires 21 March 2024                [Page 10]
Internet-Draft             DETIM Architecture             September 2023

   An RAA may assign a block of values to an individual organization.
   This is completely up to the individual RAA's published policy for
   delegation.  Such policy is out of scope.

4.3.1.  Manufacturer Unmanned Aircraft Authority (MAA)

      Author Note: with the proposal to remove solving the issue of
      putting Serial Numbers into DNS from this document, this section
      can be moved to the new document or left here.

   An HDA-level DIME run by a manufacturer of UAS systems that
   participate in Remote ID.  Stores UAS Serial Numbers under a specific
   Manufacturer Code (assigned to the manufacturer by ICAO).  The
   specific RAA (out of MCA space) and HDA use the following derivation:

   mfr_int = base34_decode(mfr_code)
   hid = (4000 << 14) + mfr_int
   mfr_code = base34_encode(hid)

   A character in a UAS Serial Number "shall include any combination of
   digits and uppercase letters, except the letters O and I, but may
   include all digits" [CTA2063A].  For HID determination, the character
   space [0-9,A-H,J-N,P-Z] is mapped to [0-34] to convert the 4 place
   Base34 Manufacturer Code to Base10 (Note this is different than the
   Base32 process in Section 4.2 of [RFC9374]).

   A DET can be encoded into a Serial Number (see [RFC9374],
   Section 4.2) and this DIME MUST hold a mapping from the Serial Number
   to the DET and its artifacts.

5.  DIME Architecture

   The DIME, in any of its roles (Section 4), is comprised of a number
   of logical components that are depicted in Figure 2.  Any of these
   components could be delegated to other entities as a service both co-
   located or remote.  For example:

   *  The Name Server component could be handled by a well-established
      DNS registrar/registry with the DRIP Provisioning Agent (DPA)
      (Section 5.1) interfacing to them

      -  Either the DPA or the Registry/Name Server interfaces to the
         DRIP Information Agent (DIA)

   *  The DPA, Registry, and Name Server may all be co-located in one
      implementation with an interface to a DIA offered by another
      organization from any one of the co-located components

Wiethuechter & Reid       Expires 21 March 2024                [Page 11]
Internet-Draft             DETIM Architecture             September 2023

     +--------------------+
     | Registering Client |
     +---------o----------+
               |
     **********|******************************************************
     *         |     DRIP Identity Management Entity (DIME)          *
     *         |                                                     *
     *  +------o-------+      +-------------+      +--------------+  *
     *  | DRIP         |      |             |      |              |  *
     *  | Provisioning o------o             |      |              |  *
     *  | Agent (DPA)  |      |             |      |              |  *
     *  +-------o------+      |             |      |              |  *
     *          |             |             |      |              |  *
     *          |             | DRIP        |      | Registration |  *
     *  +-------o--+          | Information o------o Data         |  *
     *  | Registry o----------o Agent (DIA) |      | Directory    |  *
     *  +-------o--+          |             |      | Service      |  *
     *          |             |             |      | (RDDS)       |  *
     *          |             |             |      |              |  *
     *  +-------o----------+  |             |      |              |  *
     *  | Name Server (NS) |  |             |      |              |  *
     *  +------o-----------+  +-----o-------+      +------o-------+  *
     *         |                    |                     |          *
     *         |                    |                     |          *
     **********|********************|*********************|***********
               |                    |                     |
               |            +-------o-------+             |
               '------------o Lookup Client o-------------'
                            +---------------+

                     Figure 2: DIME Logical Components

5.1.  DRIP Provisioning Agent (DPA)

   The DPA performs the important task of vetting information coming
   from clients wishing to register and then delegate (internally or
   externally) various items to other components in the DIME.

   A standard interface MUST be provided for clients to access.  An
   HTTPS based interface is RECOMMENDED.  This interface specification
   is out of scope for this document.

   There MUST be an interface from the DPA to a Registry (Section 5.2)
   component which handles the DNS specific requirements of the DIME as
   defined by the Registry.  There MAY also be interface from the DPA to
   a DRIP Information Agent (Section 5.4) as defined by the DIA.

Wiethuechter & Reid       Expires 21 March 2024                [Page 12]
Internet-Draft             DETIM Architecture             September 2023

                       +-------------+
                       | Registering |
                       |   Client    |
                       +------o------+
                              |
                              | HTTPS
                              |
                              |
                           +--o--+           +-----+
                           | DPA o-----------o DIA |
                           +--o--+    TBD    +-----+
                              |
                              |
                              | HTTPS or EPP
                              |
                       +------o---+
                       | Registry |
                       +----------+

                      Figure 3: DPA Interface Mapping

5.2.  Registry

   The Registry component handles all the required DNS based
   requirements of the DIME to function for DRIP.  This includes the
   registration and maintenance of various DNS Resource Records.

   A standardized interface MUST be implemented for interactions with
   the DPA (Section 5.1).  This interface MAY be over HTTPS using JSON/
   CBOR encoding or MAY use the Extensional Provisioning Protocol (EPP)
   [RFC5730].  The detailed specification of either of these interfaces
   is out of scope for this document.

   There MAY be interface from the Registry to a DRIP Information Agent
   (Section 5.4) as defined by the DIA.

Wiethuechter & Reid       Expires 21 March 2024                [Page 13]
Internet-Draft             DETIM Architecture             September 2023

                          +-----+
                          | DPA |
                          +--o--+
                             |
                             | HTTPS or EPP
                             |
                             |
                      +------o---+           +-----+
                      | Registry o-----------o DIA |
                      +-----o----+    TBD    +-----+
                            |
                            |
                            | TBD
                            |
                        +---o--+
                        |  NS  |
                        +------+

                    Figure 4: Registry Interface Mapping

5.3.  Name Server (NS)

   The interface of the Name Server to any component (nominally the
   Registry) in a DIME is out of scope as typically they are
   implementation specific.

      Author Note: This may be very important here as we should not
      preclude a USS from running his own Name Server but they are not
      DNS experts and will need guidance or at least pointers to it to
      not mess it up.  Such as SOA and NS formats to allow delegation if
      acting as an RAA.

Wiethuechter & Reid       Expires 21 March 2024                [Page 14]
Internet-Draft             DETIM Architecture             September 2023

                         +----------+
                         | Registry |
                         +-----o----+
                               |
                               |
                               | TBD
                               |
                           +---o--+
                           |  NS  |
                           +--o---+
                              |
                              |
                              | DNS Query/Response
                              |
                         +----o----------+
                         | Lookup Client |
                         +---------------+

                  Figure 5: Name Server Interface Mapping

5.4.  DRIP Information Agent (DIA)

   The DIA is the main component handling requests for information from
   entities outside of the DIME.  Typically this is when an Observer
   looks up a Session ID from an UA and gets pointed to the DIA to
   obtain information not available publicly (i.e. via DNS).

   The information contained in the DIA is generally more oriented
   around the Operator of a given UAS and is thus classified as
   Personally Identifiable Information (PII).  To protect the privacy of
   an Operator of the UAS this information is not publicly accessible
   and is only available behind policy driven differentiated access
   mechanisms (see Section 7).

   For DRIP, the Registration Data Access Protocol (RDAP) ([RFC7480],
   [RFC9082] and [RFC9083]) is the selected protocol to provide policy
   driven differentiated access for queries of information from clients.

   There MUST be a standardized interface for the DPA or Registry to
   add, update or delete information into the DIA.  Specific details for
   these interfaces are out of scope for this document.

   An interface defined by the Registration Data Directory Service
   (RDDS) (Section 5.5) is also required as specified by the RDDS.

Wiethuechter & Reid       Expires 21 March 2024                [Page 15]
Internet-Draft             DETIM Architecture             September 2023

                                    +-----+
                                    | DPA |
                                    +--o--+
                                       |
                                       |
                                       | TBD
                                       |
             +----------+    TBD    +--o--+             +------+
             | Registry o-----------o DIA o-------------o RDDS |
             +----------+           +--o--+     TBD     +------+
                                       |
                                       |
                                  RDAP |
                                       |
                               +-------o-------+
                               | Lookup Client |
                               +---------------+

                      Figure 6: DIA Interface Mapping

5.5.  Registration Data Directory Service (RDDS)

   This is the primary information database for the DIA.  An interface
   MUST be provided to the DIA but its specification is out of scope for
   this document.

                                +-----+
                                | DIA |
                                +--o--+
                                   |
                                   |
                                   | TBD
                                   |
                               +---o--+
                               | RDDS |
                               +--o---+
                                  |
                                  |
                                  | RDAP
                                  |
                             +----o----------+
                             | Lookup Client |
                             +---------------+

                      Figure 7: RDDS Interface Mapping

Wiethuechter & Reid       Expires 21 March 2024                [Page 16]
Internet-Draft             DETIM Architecture             September 2023

6.  Registration/Provisioning Process

   The general process for a registering party is as follows:

   1.  Verify input Endorsement(s) from registering party

   2.  Check for collision of DET and HI

   3.  Populate Registry/Name Server with resource record(s)

   4.  Populate RDDS via DIA with PII and other info

   5.  Generate and return Endorsement(s)

   In the following subsections an abbreviated form of Section 5 using
   co-located components is used to describe the flow of information.
   The data elements being transmitted between entities is marked
   accordingly in each figure for the specific examples.

   Each section has an associated appendix (Appendix C) containing DNS
   examples.

6.1.  Serial Number

      Author Note: with the proposal to remove solving the issue of
      putting Serial Numbers into DNS from this document, this section
      becomes the basis for a new document and is removed from here.

   There are four ways a Serial Number is supported by DRIP:

   1.  As a clear-text string with additional information
       (Section 6.1.1)

   2.  As a clear-text string mapped to a DET "post" generation by the
       *manufacturer* (for use in authentication) and additional
       information (Section 6.1.2)

   3.  As a clear-text string mapped to a DET "post" generation by the
       *user (via an HDA)* (for use in authentication) and additional
       information (Section 6.1.3)

   4.  As an encoding of an HI and associated DET by the *manufacturer*
       (for use in authentication) with additional information
       (Section 6.1.4)

      Note: additional information here refers to any subset of keys
      defined in Section 11.2.1.

Wiethuechter & Reid       Expires 21 March 2024                [Page 17]
Internet-Draft             DETIM Architecture             September 2023

6.1.1.  Serial Method 1

   This is where a UA is provisioned with a Serial Number by the
   manufacturer.  The Serial Number is just text string, defined by
   [CTA2063A].  The manufacturer runs an Name Server delegated under the
   Serial Number apex and points to information using a DET RR (filling
   in only the Serial Number and URI fields).

                     +-------------------+
                     | Unmanned Aircraft |
                     +--o---o------------+
                        |   ^
                    (a) |   | (b)
                        |   |
                 *******|***|*****************************
                 *      |   |    DIME: MAA               *
                 *      |   |                            *
                 *      v   |             +----------+   *
                 *   +--o---o--+          |          |   *
                 *   |   DPA   o--------->o          |   *
                 *   +----o----+   (d)    |          |   *
                 *        |               |          |   *
                 *        | (c)           | DIA/RDDS |   *
                 *        v               |          |   *
                 *   +----o--------+      |          |   *
                 *   | Registry/NS |      |          |   *
                 *   +-------------+      |          |   *
                 *                        +----------+   *
                 *                                       *
                 *****************************************

                 (a) Serial Number,
                     UA Information
                 (b) Success Code
                 (c) DET RR
                 (d) UA Information

         Figure 8: Example DIME:MAA with Serial Number Registration

6.1.2.  Serial Method 2

   This is where a UAS is provisioned with a Serial Number and DET by
   the manufacturer enabling their devices to use [drip-auth] and
   provide additional information.  A public mapping of the Serial
   Number to DET and all public artifacts MUST be provided by the
   manufacturer.  The manufacturer MUST use an MAA for this task.

Wiethuechter & Reid       Expires 21 March 2024                [Page 18]
Internet-Draft             DETIM Architecture             September 2023

   The device MAY allow the DET to be regenerated dynamically with the
   MAA.

                     +-------------------+
                     | Unmanned Aircraft |
                     +--o---o------------+
                        |   ^
                    (a) |   | (b)
                        |   |
                 *******|***|*****************************
                 *      |   |    DIME: MAA               *
                 *      |   |                            *
                 *      v   |             +----------+   *
                 *   +--o---o--+          |          |   *
                 *   |   DPA   o--------->o          |   *
                 *   +----o----+   (d)    |          |   *
                 *        |               |          |   *
                 *        | (c)           | DIA/RDDS |   *
                 *        v               |          |   *
                 *   +----o--------+      |          |   *
                 *   | Registry/NS |      |          |   *
                 *   +-------------+      |          |   *
                 *                        +----------+   *
                 *                                       *
                 *****************************************

                 (a) Serial Number,
                     UA Information,
                     Self-Endorsement: UA
                 (b) Success Code,
                     Broadcast Endorsement: MAA on UA
                 (c) DET RR, PTR RR
                 (d) UA Information

      Figure 9: Example DIME:MAA with Serial Number + DET Registration

6.1.3.  Serial Method 3

   This is where a UAS has a Serial Number (from the manufacturer) and
   the user (via a DIME) has a mechanism to generate and map a DET to
   the Serial Number after production.  This can provide dynamic signing
   keys for DRIP Authentication Messages via [drip-auth] for UAS that
   MUST fly only using Serial Numbers.  Registration SHOULD be allowed
   to any relevant DIME that supports it.  A public mapping of the DET
   to the Serial Number SHOULD be provided.

Wiethuechter & Reid       Expires 21 March 2024                [Page 19]
Internet-Draft             DETIM Architecture             September 2023

                     +-------------------+
                     | Unmanned Aircraft |
                     +--o---o------------+
                        |   ^
                    (a) |   | (b)
                        |   |
                 *******|***|*****************************
                 *      |   |      DIME                  *
                 *      |   |                            *
                 *      v   |             +----------+   *
                 *   +--o---o--+          |          |   *
                 *   |   DPA   o--------->o          |   *
                 *   +----o----+   (d)    |          |   *
                 *        |               |          |   *
                 *        | (c)           | DIA/RDDS |   *
                 *        v               |          |   *
                 *   +----o--------+      |          |   *
                 *   | Registry/NS |      |          |   *
                 *   +-------------+      |          |   *
                 *                        +----------+   *
                 *                                       *
                 *****************************************

                 (a) Serial Number,
                     UA Information,
                     Self-Endorsement: UA
                 (b) Success Code,
                     Broadcast Endorsement: DIME on UA
                 (c) DET RR
                 (d) UA Information

       Figure 10: Example DIME with Serial Number + DET Registration

6.1.4.  Serial Method 4

   This is where a UAS manufacturer chooses to use the Serial Number
   scheme defined in [RFC9374] to create Serial Numbers, their
   associated DETs for [drip-auth] and provide additional information.
   This document RECOMMENDS that the manufacturer "locks" the device
   from changing its authentication method so identifiers in both the
   Basic ID Message and Authentication Message do not de-sync.  The
   manufacturer MUST use an MAA for this task, with the mapping between
   their Manufacturer Code and the upper portion of the DET publicly
   available.

Wiethuechter & Reid       Expires 21 March 2024                [Page 20]
Internet-Draft             DETIM Architecture             September 2023

                     +-------------------+
                     | Unmanned Aircraft |
                     +--o---o------------+
                        |   ^
                    (a) |   | (b)
                        |   |
                 *******|***|*****************************
                 *      |   |    DIME: MAA               *
                 *      |   |                            *
                 *      v   |             +----------+   *
                 *   +--o---o--+          |          |   *
                 *   |   DPA   o--------->o          |   *
                 *   +----o----+   (d)    |          |   *
                 *        |               |          |   *
                 *        | (c)           | DIA/RDDS |   *
                 *        v               |          |   *
                 *   +----o--------+      |          |   *
                 *   | Registry/NS |      |          |   *
                 *   +-------------+      |          |   *
                 *                        +----------+   *
                 *                                       *
                 *****************************************

                 (a) Serial Number,
                     UA Information,
                     Self-Endorsement: UA
                 (b) Success Code,
                     Broadcast Endorsement: MAA on UA
                 (c) DET RR
                 (d) UA Information

      Figure 11: Example DIME:MAA with DRIP Serial Number Registration

6.2.  Operator

   Provided either by USS or CAA run HDAs.  Regulation might require
   interaction between them.  An Operator can request that certain
   information normally generated and provisioned into DNS be omitted
   due to privacy concerns.

Wiethuechter & Reid       Expires 21 March 2024                [Page 21]
Internet-Draft             DETIM Architecture             September 2023

    +----------+
    | Operator |
    +--o---o---+
       |   ^
   (a) |   | (b)
       |   |
*******|***|*****************************
*      |   |    DIME:HDA                *
*      |   |                            *
*      v   |             +----------+   *
*   +--o---o--+          |          |   *
*   |   DPA   o--------->o          |   *
*   +----o----+   (d)    |          |   *
*        |               |          |   *
*        | (c)           | DIA/RDDS |   *
*        v               |          |   *
*   +----o--------+      |          |   *
*   | Registry/NS |      |          |   *
*   +-------------+      |          |   *
*                        +----------+   *
*                                       *
*****************************************

(a) Operator Information,
    Operator Self-Endorsement
(b) Success Code,
    Generic Endorsement: HDA on Operator
(c) HIP RR, DET RR, TLSA RR, URI RR, PTR RR
(d) Operator Information

Note: (c) MAY be requested by the Operator to be omitted due to PII concerns.

     Figure 12: Example DIME:HDA with Operator (DET) Registration

   The definition of Operator Information is out of scope of this
   document and left to local regulations (both in its format and
   contents).

6.3.  Session ID

   Session IDs are generally handled by HDAs.  In Figure 13 the UAS
   comprises of an unmanned aircraft and a Ground Control Station (GCS).
   Both parties are involved in the registration process.

Wiethuechter & Reid       Expires 21 March 2024                [Page 22]
Internet-Draft             DETIM Architecture             September 2023

                    +---------+
                    |   UAS   |
                    +--o---o--+
                       |   ^
                   (a) |   | (b)
                       |   |
                *******|***|*****************************
                *      |   |    DIME: HDA               *
                *      |   |                            *
                *      v   |             +----------+   *
                *   +--o---o--+          |          |   *
                *   |   DPA   o--------->o          |   *
                *   +----o----+   (d)    |          |   *
                *        |               |          |   *
                *        | (c)           | DIA/RDDS |   *
                *        v               |          |   *
                *   +----o--------+      |          |   *
                *   | Registry/NS |      |          |   *
                *   +-------------+      |          |   *
                *                        +----------+   *
                *                                       *
                *****************************************

                (a) Mutual Endorsement: HDA on GCS,
                    Generic Endorsement: GCS on UA,
                    Session ID Information
                (b) Success Code,
                    Broadcast Endorsement: HDA on UA,
                    Generic Endorsement: HDA on UAS
                (c) HIP RR, DET RR, TLSA RR, URI RR, PTR RR
                (d) Session ID Information

       Figure 13: Example DIME:HDA with Session ID (DET) Registration

   Through mechanisms not specified in this document the Operator should
   have methods (via the GCS) to instruct the unmanned aircraft onboard
   systems to generate a keypair, DET and Self-Endorsement: UA.  The
   Self-Endorsement: UA is extracted by the Operator onto the GCS.

   The GCS is already pre-provisioned and registered to the DIME with
   its own keypair, DET, Self-Endorsement: GCS and Generic Endorsement:
   HDA on GCS.  The GCS creates a new Generic Endorsement: GCS on UA and
   also creates Mutual Endorsement: HDA on GCS.  These new endorsements
   along with Session ID Information are sent to the DIME via a secure
   channel.

Wiethuechter & Reid       Expires 21 March 2024                [Page 23]
Internet-Draft             DETIM Architecture             September 2023

   The GCS injects the Broadcast Endorsement: HDA on UA securely into
   the unmanned aircraft.  Endorsement: HDA on GCS is securely stored by
   the GCS.

      Note: in Figure 13 the Session ID Information is expected to
      contain the Serial Number along with other PII specific
      information (such as UTM data) related to the Session ID.

   Session ID Information is defined as the current model:

   sessionid_info = {
       serial: tstr .size 20,
       session_id: tstr,
       operational_intent: tstr,
       intent_src: tstr,
       operator_id: tstr,
       session_context: tstr,
       * tstr: any
   }

   Future standards or implementations MAY add other keys to this list
   (for local features and/or local regulation).

6.3.1.  UA Based Session ID

   There may be some unmanned aircraft that have their own Internet
   connectivity allowing them to register a Session ID themselves
   without outside help from other devices such as a GCS.  When such a
   system is in use its imperative that the Operator has some method to
   create the Generic Endorsement: Operator on UA to send to the DIME.
   The process and methods to perform this are out of scope for this
   document but MUST be done in a secure fashion.

6.3.2.  UAS Based Session ID

   Most unmanned aircraft will not have their own Internet connectivity
   but will have a connection to a GCS.  Typically a GCS is an
   application on a user device (such as smartphone) that allow the user
   to fly their aircraft.  For the Session ID registration the DIME MUST
   be provided with an Generic Endorsement: GCS on UA which implies
   there is some mechanism extracting and inserting information from the
   unmanned aircraft to the GCS.  These methods MUST be secure but are
   out of scope for this document.

   With this system it is also possible to have the GCS generate the DET
   based Session ID and insert it securely into the unmanned aircraft
   after registration is done.  This is NOT RECOMMENDED as this
   invalidates the objective of the asymmetric cryptography in the

Wiethuechter & Reid       Expires 21 March 2024                [Page 24]
Internet-Draft             DETIM Architecture             September 2023

   underlying DET as the private key MAY get in the possession of
   another entity other than the unmanned aircraft.  See Section 12.2
   for more details.

6.4.  Child DIME

   Handled by the Apex and RAA's.  This is an endpoint that handles
   dynamic registration (or key roll-over) of lower-level DIMEs (RAAs to
   Apex and HDAs to RAAs) in the hierarchy.

                    +---------------+
                    |   DIME: HDA   |
                    +--o---o--------+
                       |   ^
                   (a) |   | (b)
                       |   |
                *******|***|*****************************
                *      |   |    DIME: RAA               *
                *      |   |                            *
                *      v   |             +----------+   *
                *   +--o---o--+          |          |   *
                *   |   DPA   o--------->o          |   *
                *   +----o----+   (d)    |          |   *
                *        |               |          |   *
                *        | (c)           | DIA/RDDS |   *
                *        v               |          |   *
                *   +----o--------+      |          |   *
                *   | Registry/NS |      |          |   *
                *   +-------------+      |          |   *
                *                        +----------+   *
                *                                       *
                *****************************************

                (a) Self-Endorsement: HDA,
                    HDA Information or
                    Generic Endorsement: old HDA, new HDA
                (b) Success Code,
                    Broadcast Endorsement: RAA on HDA
                (c) HIP RR, DET RR, TLSA RR, URI RR, PTR RR
                (d) HDA Information

           Figure 14: Example DIME:RAA with DIME:HDA Registration

Wiethuechter & Reid       Expires 21 March 2024                [Page 25]
Internet-Draft             DETIM Architecture             September 2023

   It should be noted that this endpoint DOES NOT hand out dynamically
   RAA/HDA values to systems that hit the endpoint.  This is done out-
   of-band through processes specified by local regulations and
   performed by cognizant authorities.  The endpoint MUST NOT accept
   queries it is not previously informed of being expected via
   mechanisms not defined in this document.

   It is OPTIONAL to implement this endpoint.  This MAY be used to
   handle lower-level DIME key roll-over.

7.  Differentiated Access Process

   Per [RFC9434] all information classified as public is stored in a
   datastore protected using some form of differentiated access (i.e.
   AAA) to satisfy REG-2 from [RFC9153].

   Differentiated access, as a process, is a requirement for DIMEs as
   defined in [RFC9153] by the combination of PRIV-1, PRIV-3, PRIV-4,
   REG-2 and REG-4.  [RFC9434] further elaborates on the concept by
   citing RDAP (from [RFC7480], [RFC9082] and [RFC9083]) as a potential
   means of fulfilling this requirement.

   Typically the cognizant authority is the primary querant of private
   information from a DIME if a Session ID is reported (the case of the
   owner of the private information is ignored for the moment).  This
   capability MAY be delegated to other parties at the authorities
   discretion (be it to a single user or many), thus requiring a
   flexible system to delegate, determine and revoke querent access
   rights for information.  XACML MAY be a good technology choice for
   this flexibility.

   It is noted by the authors that as this system scales the problem
   becomes a, well known and tricky, key management problem.  While
   recommendations for key management are useful they are not
   necessarily in scope for this document as best common practices
   around key management should already be mandated and enforced by the
   cognizant authorities in their existing systems.  This document
   instead focuses on finding a balance for generic wide-spread
   interoperability between DIMEs with authorities and their existing
   systems in a Differentiated Access Process (DAP).

   A system where cognizant authorities would require individual
   credentials to each HDA is not scalable, nor practical.  Any change
   in policy would require the authority to interact with every single
   HDA (active or inactive) to grant or revoke access; this would be
   tedious and prone to mistakes.  A single credential for a given
   authority is also strongly NOT RECOMMENDED due to the security
   concerns it would entail if it leaked.

Wiethuechter & Reid       Expires 21 March 2024                [Page 26]
Internet-Draft             DETIM Architecture             September 2023

   A zero-trust model would be the most appropriate for a DAP; being
   highly flexible and robust.  Most authorities however use "oracle"
   based systems with specific user credentials and the oracle knowing
   the access rights for a given user.  This would require the DAP the
   have some standard mechanism to locate and query a given oracle for
   information on the querent to determine if access is granted.

   DRIP has no intention to develop a new "art" of key management,
   instead hoping to leverage existing systems and be flexible enough to
   adapt as new ones become popular.

8.  DRIP in the Domain Name System

   Per [RFC9434] all information classified as public is stored in the
   DNS to satisfy REG-1 from [RFC9153].

   The apex for domain names MUST be under the administrative control of
   ICAO, the international treaty organization providing the critical
   coordination platform for civil aviation.  ICAO SHOULD be responsible
   for the operation of the DNS-related infrastructure for these domain
   name apexes.  It MAY chose to run that infrastructure directly or
   outsource it to competent third parties or some combination of the
   two.  ICAO SHOULD specify the technical and administrative criteria
   for the provision of these services: contractual terms (if any),
   reporting, uptime, SLAs (if any), DNS query handling capacity,
   response times incident handling, complaints, law enforcement
   interaction and so on.

   The delegation of civil aviation authorities to RAAs is already done
   per Section 4.2.1 using their ISO 3166-1 Numeric Codes.  Since these
   are public, any entity can stand up an RAA with that value.  ICAO
   SHOULD be the root of trust in a Endorsement or certificate chain
   that provides validation of any of these specific RAAs, in the ISO
   RAA range, thus protecting against bad actors standing up fraudulent
   RAAs.  This also ensures DRIP complies with national law and
   regulation since these are matters of national sovereignty.

Wiethuechter & Reid       Expires 21 March 2024                [Page 27]
Internet-Draft             DETIM Architecture             September 2023

   Each national aviation authority SHOULD be responsible for the
   operation of the DNS-related infrastructure for their delegated
   subdomains.  As with the domain apexes overseen by ICAO, each
   national aviation authority MAY chose to run that infrastructure
   directly or outsource it to competent third parties or some
   combination of the two.  National aviation authorities SHOULD specify
   the technical and administrative criteria for the provision of these
   services: contractual terms (if any), reporting, uptime, SLAs (if
   any), DNS query handling capacity, response times, incident handling,
   complaints, law enforcement interaction and so on.  These are
   National Matters where national law/regulation prevail.  National
   policy and regulations will define how long DNS data are stored or
   archived.

   DNSSEC is strongly RECOMMENDED (especially for RAA-level and higher
   zones).  When a DIME decides to use DNSSEC they SHOULD define a
   framework for cryptographic algorithms and key management [RFC6841].
   This may be influenced by frequency of updates, size of the zone, and
   policies.

8.1.  DRIP Entity Tags

   The REQUIRED mechanism is to place any information into ip6.arpa when
   using a DET.  Since the DET is an IPv6 address it can be nibble-
   reversed and used in the zone, per standard conventions.

   The prefix 2001:30/28 is registered with IANA [RFC9374] and
   3.0.0.1.0.0.2.ip6.arpa - the corresponding reverse domain - SHOULD be
   under the administrative control of the Apex.  In addition to the DNS
   infrastructure for 3.0.0.1.0.0.2.ip6.arpa, the Apex SHOULD be
   responsible for the allocation of IPv6 addresses in this prefix.  An
   addressing plan will need to be developed.

   Distribution of HHIT (IPv6 address) blocks SHOULD be done using the
   14-bit RAA space as a framework.  The Apex SHOULD allocate blocks to
   each entity who can then assign them to HDAs in accordance with local
   law and policy.  All HDAs MUST have an IPv6 address in 2001:30/28.  A
   discrete zone SHOULD be delegated for each HDA.  These MUST contain
   an DET resource record (Section 8.1.1) for itself.

   Reverse lookups of these IPv6 addresses will translate the address
   into a domain name in the manner defined in [RFC1886].  However,
   these lookups will query for, depending on what is required: HIP,
   DET, TLSA, URI, or PTR RRTypes.

8.1.1.  DET Resource Record

Wiethuechter & Reid       Expires 21 March 2024                [Page 28]
Internet-Draft             DETIM Architecture             September 2023

      Author Note: This section is very much a WIP, comments are
      welcome.

   <domain> DET IN ( DET TYPE STATUS HID [SN] Endorsement )

   DET = Base16 DET
   TYPE = enumeration of Type of DET
   STATUS = enumeration of Status of DET
   HID = HID Abbreviation
   SN = Serial Number (optional)
   Endorsement = Broadcast Endorsement in CBOR encoding

   With the SN parameter this covers the "public mapping to DET" when a
   user/manufacturer already has a Serial Number that can not change and
   wishes to do DRIP Authentication.

8.1.1.1.  HID Abbreviation

   On receiver devices a DET can be translated to a more human readable
   form such as: {RAA Abbreviation} {HDA Abbreviation} {Last 4
   Characters of DET Hash}. An example of this would be US FAA FE23.

   To support this DIMEs are RECOMMENDED to have an abbreviation that
   could be used for this form.  These abbreviations SHOULD be a maximum
   of six characters (for each section) in length.  Spaces MUST NOT be
   used and be replaced with either underscores (_) or dashes (-).

   The concatenation of {RAA Abbreviation} and {HDA Abbreviation} with a
   space between them is what fills in the HID field of the DET RR in
   Section 8.1.1.

   For RAAs allocated in the ISO range Section 4.2.1, the RAA
   abbreviation MUST be set to the ISO 3166-1 country code (either
   Alpha-2 or Alpha-3).

   If a DIME does not have an abbreviation or it can not be looked up
   then the receiver MUST use the uppercase 4-character hexadecimal
   encoding of the field it is missing.

8.2.  Serial Numbers & Other UAS ID Types

      Author Note: with the proposal to remove solving the issue of
      putting Serial Numbers into DNS from this document, this section
      is removed and becomes part of a new document.

      Author Note: There MUST be an entry point in DNS for the lookup of
      UAS Serial Numbers.  This section is very much a shot in the dark.

Wiethuechter & Reid       Expires 21 March 2024                [Page 29]
Internet-Draft             DETIM Architecture             September 2023

   This document specifies the creation and delegation to ICAO of the
   subdomain uas.icao.arpa.  To enable lookup of Serial Numbers a
   subdomains of sn.uas.icao.arpa is maintained.  All entries under
   sn.uas.icao.arpa are to follow the convention found in Appendix A.2.
   This is to enable a singular lookup point for Serial Numbers for UAS.

   Note that other subdomains under uas.icao.arpa can be made to support
   other identifiers in UAS.  The creation and use of other such other
   subdomains are out of scope for this document.  The further use and
   creation of items under icao.arpa is the authority of ICAO (which has
   been delegated control).

   DETs MUST not have a subdomain in uas.icao.arpa (such as
   det.uas.icao.arpa) as they fit within the predefined ip6.arpa as they
   are IPv6 addresses.

9.  Endorsements

   DRIP Endorsements are defined in a CDDL [RFC8610] structure
   (Figure 15) that can be encoded to CBOR, JSON or have their CDDL keys
   removed and be sent as a binary blob.  When the latter is used very
   specific forms are defined with naming conventions to know the data
   fields and their lengths for parsing and constrained envirornments.
   CBOR is the preferred encoding format.

   The CDDL was derived from the more specific structure developed for
   [drip-auth].  As such the structures found in [drip-auth], such as
   the UA Signed Evidence and the contents of DRIP Link (known as a
   Broadcast Endorsement), are a subset of the below definition in a
   strict binary form.

   Appendix B specifies specific Endorsement structures for the UAS RID
   use-case.

      Note: this section uses the term HHIT instead of DET as the
      Endorsements are designed to be generic and re-useable for other
      HHIT use-cases.  Specific use-cases SHOULD add new keys for each
      section (if required) and define the valid keys and encoding forms
      for their use-case.

9.1.  Endorsement Structure

Wiethuechter & Reid       Expires 21 March 2024                [Page 30]
Internet-Draft             DETIM Architecture             September 2023

     endorsement = {
         ; TODO: add tag for self-describing type or leave up to cbor?
         scope: {
             vnb: number,
             vna: number,
             * tstr => any
         },
         evidence: bstr,
         endorser: {
             identity: {
                 hhit: bstr .size 16, ? hi: bstr // * tstr => any
             },
             signature: {
                 sig: bstr,
                 * tstr => any
             }
         }
     }

                        Figure 15: Endorsement CDDL

9.1.1.  Scope

   The scope section is more formally "the scope of validity of the
   endorsement".  The scope can come in various forms but MUST always
   have a "valid not before" (vnb) and "valid not after" (vna)
   timestamps.

   Other forms of the scope could for example be a 4-dimensional volume
   definition.  This could be in raw latitude, longitude, altitude pairs
   or may be a URI pointing to scope information.  Additional scope
   fields are out of scope for this document and should be defined for
   specific Endorsement structures if they are desired.

9.1.2.  Evidence

   The evidence section contain a byte string of evidence.  Specific
   content of evidence (such as subfields, length and ordering) is
   defined in specific Endorsement structures.

9.1.3.  Identity

   The identity section is where the main identity information of the
   signer of the Endorsement is found.  The identity can take many forms
   such as a handle to the identity (e.g. an HHIT), or can include more
   explicit data such as the public key (e.g. an HI).  Other keys, for
   different identifiers, can be provided and MUST be defined in their
   specific Endorsement.

Wiethuechter & Reid       Expires 21 March 2024                [Page 31]
Internet-Draft             DETIM Architecture             September 2023

   The length of the hi can be determined when using hhit by decoding
   the provided IPv6 address.  The prefix will inform of the ORCHID
   construction being used, which informs the locations of the OGA ID in
   the address.  The OGA ID will then inform the user of the key
   algorithm selected which has the key length defined.

9.1.4.  Signature

   The signature section contain the signature data for the Endorsement.
   The signature itself MUST be provided under the sig key.  Other forms
   or data elements could also be present in the signature section if
   specified in a specific Endorsement.  Signatures MUST be generated
   using the preceding sections in their binary forms (i.e. as a
   bytestring with no keys).

10.  X.509 Certificates

10.1.  Certificate Policy and Certificate Stores

   X.509 certificates are optional for the DRIP entities covered in this
   document.  DRIP endpoint entities (EE) (i.e., UA, GCS, and Operators)
   may benefit from having X.509 certificates.  Most of these
   certificates will be for their DET and some will be for other UAS
   identities.  To provide for these certificates, some of the other
   entities (e.g.  USS) covered in this document will also have
   certificates to create and manage the necessary PKI structure.

   Three certificate profiles are defined, with examples, and explained
   in [drip-dki].  Each has a specific role to play and an EE may have
   its DET enrolled in all of them.  There is a 'Lite' profile that
   would work well enough on constrained communication links for those
   instances where various issues push the use of X.509.  There is a
   'Basic; profile that is more in line with [RFC5280] recommendations,
   but is still small enough for many constrained environments.  Finally
   there is a profile to directly add DET support into the civil/general
   aviation certificates as discussed below.

   A Certificate Authority (CA) supporting DRIP entities MAY adhere to
   the ICAO's Aviation Common Certificate Policy (ACCP) [ICAO-IATF-CP-
   draft].  The CA(s) supporting this CP MUST either be a part of the
   ACCP cross-certification or part of the ACCP CA Trust List.  It is
   possible that future versions of the ACCP will directly support the
   DRIP Basic profile.

      Note ACCP is: ICAO Doc 10169 Aviation Common Certificate Policy
      (ACCP).  I can't get a url for that, but so far these is no
      changes from v 0.93 of the old IATF CP; changes are in the works
      then will be posted, so continue to reference IATF CP

Wiethuechter & Reid       Expires 21 March 2024                [Page 32]
Internet-Draft             DETIM Architecture             September 2023

   EEs may use their X.509 certificates, rather than their rawPublicKey
   (i.e.  HI) in authentication protocols (as not all may support
   rawPublicKey identities).  Short lived DETs like those used for a
   single operation or even for a day's operations may not benefit from
   X.509.  Creating then almost immediately revoking these certificates
   is a considerable burden on all parts of the system.  Even using a
   short notAfter date will not completely mitigate the burden of
   managing these certificates.  That said, many EEs will benefit to
   offset the effort.  It may also be a regulator requirement to have
   these certificates.  Finally, certificates can provide the context of
   use for a DET (via policy constraint OIDs).

   Typically an HDA either does or does not issue a certificate for all
   its DETs.  An RAA may specifically have some HDAs for DETs that do
   not want/need certificates and other HDAs for DETs that do need them.
   These types of HDAs could be managed by a single entity thus
   providing both environments for its customers.

   It is recommended that DRIP X.509 certificates be stored as DNS TLSA
   Resource Records, using the DET as the lookup key.  This not only
   generally improves certificate lookups, but also enables use of DANE
   [RFC6698] for the various servers in the UTM and particularly DIME
   environment and DANCE [dane-clients] for EEs (e.g.
   [drip-secure-nrid-c2]).  All DRIP certificates MAY alternatively be
   available via RDAP.  LDAP/OCSP access for other UTM and ICAO uses
   SHOULD also be provided.

10.2.  Certificate Management

   PKIX standard X.509 issuance practices should be used.  The
   certificate request SHOULD be included in the DET registration
   request.  A successful DET registration then MUST include certificate
   creation, store, and return to the DET registrant.  It is possible
   that the DET registration is actually an X.509 registration.  For
   example, PKIX CSR may be directly used and the DET registration and
   Endorsement creation are a addition to this process.  Further ACME
   may be directly extendable to provide the DET registration.

   Note that CSRs do not include the certificate validityDate; adding
   that is done by the CA.  If in the registration process, the EE is
   the source of notBefore and notAfter dates, they need to be sent
   along with the CSR.

   Certificate revocation will parallel DET revocation.  TLSA RR MUST be
   deleted from DNS and RDAP, LDAP, and OCSP return revoked responses.
   CRLs SHOULD be maintained per the CP.

Wiethuechter & Reid       Expires 21 March 2024                [Page 33]
Internet-Draft             DETIM Architecture             September 2023

10.3.  Examples

   For full examples of X.509 Certificates and the process to use them
   see [drip-dki].

10.4.  Alternative Certificate Encoding

   (CBOR encoded certs here.  TBD)

11.  IANA Considerations

11.1.  Delegation of Nibble Reversed IPv6 Prefix

   For DRIP to function in a interoperable way the easiest way to allow
   look up of DETs is through the already existing ip6.arpa domain
   structure (as defined in this document).  Here IPv6 addresses are
   nibble reversed and usually have PTR records.

   With DRIP the prefix 2001:30/28 has been allocated by IANA already
   for DRIP use.  However its representative reverse domain in ip6.arpa
   has not.

   There are a number of questions in this area for DRIP:

   1.  What organization would have administrative control over the
       nibble-reversed ip6.arpa block for 2001:30/28?

       *  How do they obtain this and from whom?

       *  What is the SLA between IANA/ICANN and the administrative
          organization for nibble-reversed 2001:30/28?

   2.  What organization would have technical control (i.e. day to day
       operations) over the nibble-reversed ip6.arpa block for
       2001:30/28?

   3.  How are delegation/allocation of further nibble-reversed sub-
       blocks from 2001:30/28 handled by the administrative
       organization?

       *  This is partly covered in this document already
          (Apex->RAA->HDA)

       *  What is the SLA between the administrative organization and
          sub-organizations given delegations/allocations?  This might
          be more general guidelines than an actual SLA?

Wiethuechter & Reid       Expires 21 March 2024                [Page 34]
Internet-Draft             DETIM Architecture             September 2023

   4.  What goes into a nibble-reversed ip6.arpa domain for DRIP at each
       level?

   This is not an exhaustive list of questions, this is more to get
   discussion going.

11.2.  IANA DRIP Registry

11.2.1.  Aircraft Information Registry

   This document requests a new registry for aircraft information fields
   under the DRIP registry group (https://www.iana.org/assignments/drip/
   drip.xhtml).

   Aircraft Information Fields:  list of acceptable keys to be used in
      UA Information during a UA registration to a DIME.  Future
      additions to this registry are to be made through First Come First
      Served (Section 4.4 of [RFC8126]).  The following values are
      defined:

         +======================+=======+========================+
         | Key Name             | Type  | Description            |
         +======================+=======+========================+
         | length               | float | length, in millimeters |
         +----------------------+-------+------------------------+
         | width                | float | width, in millimeters  |
         +----------------------+-------+------------------------+
         | height               | float | height, in millimeters |
         +----------------------+-------+------------------------+
         | constructionMaterial | tstr  | materials, comma       |
         |                      |       | separated if multiple  |
         +----------------------+-------+------------------------+
         | color                | tstr  | colors, comma          |
         |                      |       | separated if multiple  |
         +----------------------+-------+------------------------+
         | serial               | tstr  | ANSI CTA 2063-A Serial |
         |                      |       | Number                 |
         +----------------------+-------+------------------------+
         | manufacturer         | tstr  | manufacturer name      |
         +----------------------+-------+------------------------+
         | make                 | tstr  | aircraft make          |
         +----------------------+-------+------------------------+
         | model                | tstr  | aircraft model         |
         +----------------------+-------+------------------------+
         | dryWeight            | float | weight of aircraft     |
         |                      |       | with no payloads       |
         +----------------------+-------+------------------------+
         | numRotors            | int   | Number of rotators     |

Wiethuechter & Reid       Expires 21 March 2024                [Page 35]
Internet-Draft             DETIM Architecture             September 2023

         +----------------------+-------+------------------------+
         | propLength           | float | Length of props, in    |
         |                      |       | centimeters            |
         +----------------------+-------+------------------------+
         | numBatteries         | int   |                        |
         +----------------------+-------+------------------------+
         | batteryCapacity      | float | in milliampere hours   |
         +----------------------+-------+------------------------+
         | batteryWeight        | float | in kilograms           |
         +----------------------+-------+------------------------+
         | batteryVoltage       | float | in volts               |
         +----------------------+-------+------------------------+
         | batteryChemistry     | tstr  |                        |
         +----------------------+-------+------------------------+
         | maxTakeOffWeight     | float | in kilograms           |
         +----------------------+-------+------------------------+
         | maxPayloadWeight     | float | in kilograms           |
         +----------------------+-------+------------------------+
         | maxFlightTime        | float | in minutes             |
         +----------------------+-------+------------------------+
         | minOperatingTemp     | float | in Celsius             |
         +----------------------+-------+------------------------+
         | maxOperatingTemp     | float | in Celsius             |
         +----------------------+-------+------------------------+
         | ipRating             | tstr  | standard IP rating     |
         +----------------------+-------+------------------------+
         | engineType           | tstr  |                        |
         +----------------------+-------+------------------------+
         | fuelType             | tstr  |                        |
         +----------------------+-------+------------------------+
         | fuelCapacity         | float | in liters              |
         +----------------------+-------+------------------------+
         | previousSerial       | tstr  | legacy serial          |
         |                      |       | number(s)              |
         +----------------------+-------+------------------------+

                                  Table 2

11.2.2.  Endorsement Fields

   This document requests a new registry for Endorsement fields under
   the DRIP registry group (https://www.iana.org/assignments/drip/
   drip.xhtml).

   Endorsement Fields:  list of field keys to be used in an Endorsement
      and what section(s) they can be used in.  Future additions to this
      registry are to be made through First Come First Served
      (Section 4.4 of [RFC8126]).  The following values are defined:

Wiethuechter & Reid       Expires 21 March 2024                [Page 36]
Internet-Draft             DETIM Architecture             September 2023

    +============+========+===========+==============================+
    | Field Name | Type   | Useable   | Description                  |
    |            |        | Sections  |                              |
    +============+========+===========+==============================+
    | vna        | number | scope     | Valid Not After, UTC Unix    |
    |            |        |           | Timestamp                    |
    +------------+--------+-----------+------------------------------+
    | vnb        | number | scope     | Valid Not Before, UTC Unix   |
    |            |        |           | Timestamp                    |
    +------------+--------+-----------+------------------------------+
    | hhit       | bstr   | identity  | Hierarchial Host Identity    |
    |            |        |           | Tag (HHIT), fixed size of 16 |
    +------------+--------+-----------+------------------------------+
    | hi         | bstr   | identity  | Host Identity (HI)           |
    +------------+--------+-----------+------------------------------+
    | sig        | bstr   | signature | Signature                    |
    +------------+--------+-----------+------------------------------+

                                 Table 3

12.  Security Considerations

12.1.  Key Rollover & Federation

   During key rollover the DIME MUST inform all children and parents of
   the change - using best standard practices of a key rollover.

   A DET has a natural ability for a single DIME to hold different
   cryptographic identities under the same HID values.  This is due to
   the lower 64-bits of the DET being a hash of the public key and the
   HID of the DET being generated.  As such during key rollover, only
   the lower 64-bits would change and a check for a collision would be
   required.

   This attribute could also allow for a single DIME to be "federated"
   across multiple DETs sharing the same HID value.  This method of
   deployment has not been thoroughly studied at this time.  An endpoint
   such as in Section 6.4 is a possible place to have these functions.

12.2.  DET Generation

      Author Note: is this section valid anymore?  Perhaps we hard
      specify that devices ONLY generate on their own hardware instead
      of "out-sourcing" as this section implies.

   Under the FAA [NPRM], it is expecting that IDs for UAS are assigned
   by the UTM and are generally one-time use.  The methods for this
   however are unspecified leaving two options.

Wiethuechter & Reid       Expires 21 March 2024                [Page 37]
Internet-Draft             DETIM Architecture             September 2023

   Option 1:

      The entity generates its own DET, discovering and using the RAA
      and HDA for the target DIME.  The method for discovering a DIME's
      RAA and HDA is out of scope here.  This allows for the device to
      generate an DET to send to the DIME to be accepted (thus
      generating the required Self-Endorsement) or denied.

   Option 2:

      The entity sends to the DIME its HI for it to be hashed and result
      in the DET.  The DIME would then either accept (returning the DET
      to the device) or deny this pairing.

   Keypairs are expected to be generated on the device hardware it will
   be used on.  Due to hardware limitations and connectivity it is
   acceptable, though not recommended, under DRIP to generate keypairs
   for the Aircraft on Operator devices and later securely inject them
   into the Aircraft.  The methods to securely inject and store keypair
   information in a "secure element" of the Aircraft is out of scope of
   this document.

13.  Contributors

   Thanks to Stuart Card (AX Enterprize, LLC) and Bob Moskowitz (HTT
   Consulting, LLC) for their early work on the DRIP registries concept.
   Their early contributions laid the foundations for the content and
   processes of this architecture and document.  Bob Moskowitz is also
   instrumental in the PKIX work defined in this document with his
   parallel work in ICAO.

14.  References

14.1.  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,
              <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>.

Wiethuechter & Reid       Expires 21 March 2024                [Page 38]
Internet-Draft             DETIM Architecture             September 2023

   [RFC8610]  Birkholz, H., Vigano, C., and C. Bormann, "Concise Data
              Definition Language (CDDL): A Notational Convention to
              Express Concise Binary Object Representation (CBOR) and
              JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,
              June 2019, <https://www.rfc-editor.org/info/rfc8610>.

   [RFC9153]  Card, S., Ed., Wiethuechter, A., Moskowitz, R., and A.
              Gurtov, "Drone Remote Identification Protocol (DRIP)
              Requirements and Terminology", RFC 9153,
              DOI 10.17487/RFC9153, February 2022,
              <https://www.rfc-editor.org/info/rfc9153>.

   [RFC9374]  Moskowitz, R., Card, S., Wiethuechter, A., and A. Gurtov,
              "DRIP Entity Tag (DET) for Unmanned Aircraft System Remote
              ID (UAS RID)", RFC 9374, DOI 10.17487/RFC9374, March 2023,
              <https://www.rfc-editor.org/info/rfc9374>.

   [RFC9434]  Card, S., Wiethuechter, A., Moskowitz, R., Zhao, S., Ed.,
              and A. Gurtov, "Drone Remote Identification Protocol
              (DRIP) Architecture", RFC 9434, DOI 10.17487/RFC9434, July
              2023, <https://www.rfc-editor.org/info/rfc9434>.

14.2.  Informative References

   [CTA2063A] "ANSI/CTA 2063-A Small Unmanned Aerial Systems Numbers",
              September 2019, <https://shop.cta.tech/products/small-
              unmanned-aerial-systems-serial-numbers>.

   [dane-clients]
              Huque, S. and V. Dukhovni, "TLS Client Authentication via
              DANE TLSA records", Work in Progress, Internet-Draft,
              draft-ietf-dance-client-auth-02, 12 May 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-dance-
              client-auth-02>.

   [drip-auth]
              Wiethuechter, A., Card, S. W., and R. Moskowitz, "DRIP
              Entity Tag Authentication Formats & Protocols for
              Broadcast Remote ID", Work in Progress, Internet-Draft,
              draft-ietf-drip-auth-32, 18 September 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-drip-
              auth-32>.

   [drip-dki] Moskowitz, R. and S. W. Card, "The DRIP DET public Key
              Infrastructure", Work in Progress, Internet-Draft, draft-
              moskowitz-drip-dki-07, 10 July 2023,
              <https://datatracker.ietf.org/doc/html/draft-moskowitz-
              drip-dki-07>.

Wiethuechter & Reid       Expires 21 March 2024                [Page 39]
Internet-Draft             DETIM Architecture             September 2023

   [drip-secure-nrid-c2]
              Moskowitz, R., Card, S. W., Wiethuechter, A., and A.
              Gurtov, "Secure UAS Network RID and C2 Transport", Work in
              Progress, Internet-Draft, draft-moskowitz-drip-secure-
              nrid-c2-12, 26 March 2023,
              <https://datatracker.ietf.org/doc/html/draft-moskowitz-
              drip-secure-nrid-c2-12>.

   [NPRM]     "Notice of Proposed Rule Making on Remote Identification
              of Unmanned Aircraft Systems", December 2019.

   [RFC1886]  Thomson, S. and C. Huitema, "DNS Extensions to support IP
              version 6", RFC 1886, DOI 10.17487/RFC1886, December 1995,
              <https://www.rfc-editor.org/info/rfc1886>.

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
              <https://www.rfc-editor.org/info/rfc5280>.

   [RFC5730]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
              STD 69, RFC 5730, DOI 10.17487/RFC5730, August 2009,
              <https://www.rfc-editor.org/info/rfc5730>.

   [RFC6698]  Hoffman, P. and J. Schlyter, "The DNS-Based Authentication
              of Named Entities (DANE) Transport Layer Security (TLS)
              Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August
              2012, <https://www.rfc-editor.org/info/rfc6698>.

   [RFC6841]  Ljunggren, F., Eklund Lowinder, AM., and T. Okubo, "A
              Framework for DNSSEC Policies and DNSSEC Practice
              Statements", RFC 6841, DOI 10.17487/RFC6841, January 2013,
              <https://www.rfc-editor.org/info/rfc6841>.

   [RFC7480]  Newton, A., Ellacott, B., and N. Kong, "HTTP Usage in the
              Registration Data Access Protocol (RDAP)", STD 95,
              RFC 7480, DOI 10.17487/RFC7480, March 2015,
              <https://www.rfc-editor.org/info/rfc7480>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

Wiethuechter & Reid       Expires 21 March 2024                [Page 40]
Internet-Draft             DETIM Architecture             September 2023

   [RFC9082]  Hollenbeck, S. and A. Newton, "Registration Data Access
              Protocol (RDAP) Query Format", STD 95, RFC 9082,
              DOI 10.17487/RFC9082, June 2021,
              <https://www.rfc-editor.org/info/rfc9082>.

   [RFC9083]  Hollenbeck, S. and A. Newton, "JSON Responses for the
              Registration Data Access Protocol (RDAP)", STD 95,
              RFC 9083, DOI 10.17487/RFC9083, June 2021,
              <https://www.rfc-editor.org/info/rfc9083>.

Appendix A.  DRIP Fully Qualified Domain Names

A.1.  DRIP Entity Tag

      {hash}.{oga_id}.{hda}.{raa}.{prefix}.{apex}.

   When building a DET FQDN it MUST must be built using the exploded
   (all padding present) form of the IPv6 address.

   Apex: .example.com
   DET: 2001:0030:0280:1405:c465:1542:a33f:dc26
   ID: c4651542a33fdc26
   OGA: 05
   HID: 0028014
   HDA: 0014
   RAA: 000a
   Prefix: 2001003
   FQDN: c4651542a33fdc26.05.0014.000a.2001003.example.com

A.2.  UAS Serial Number

      Author Note: with the proposal to remove solving the issue of
      putting Serial Numbers into DNS from this document, this section
      is removed and part of a new document.

      {id}.{length}.{manufacturer-code}.{apex}.

   Apex: .sn.uas.icao.arpa.
   Serial: MFR0ADR1P1SC00L
   Manufacturer Code: MFR0
   Length: A
   ID: DR1P1SC00L
   FQDN: dr1p1sc00l.a.mfr0.sn.uas.icao.arpa.

Appendix B.  DRIP Endorsements for UAS

B.1.  Generic Endorsement

Wiethuechter & Reid       Expires 21 March 2024                [Page 41]
Internet-Draft             DETIM Architecture             September 2023

                      generic_endorsement = {
                          scope: {
                              vnb: number,
                              vna: number
                          },
                          evidence: bstr,
                          endorser: {
                              identity: {
                                  hhit: bstr .size 16
                              },
                              signature: {
                                  sig: bstr
                              }
                          }
                      }

                    Figure 16: Generic Endorsement CDDL

   evidence is a binary string with specified contents (in format and
   ordering) by specific use-cases.  As an example this format is used
   by [drip-auth] to support Authentication over F3411 constrained
   links. evidence data is defined by [drip-auth] for DRIP Wrapper,
   Manifest and Frame formats.

B.2.  Self Endorsement

                      self_endorsement = {
                          scope: {

                              vnb: number,
                              vna: number
                          },
                          evidence: bstr,
                          endorser: {
                              identity: {
                                  hhit: bstr .size 16
                              },
                              signature: {
                                  sig: bstr
                              }
                          }
                      }

                      Figure 17: Self Endorsement CDDL

   Used during registration process as an input. evidence is filled with
   the corresponding HI of the hhit.

Wiethuechter & Reid       Expires 21 March 2024                [Page 42]
Internet-Draft             DETIM Architecture             September 2023

     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
     +---------------+---------------+---------------+---------------+
     |                              VNB                              |
     +---------------+---------------+---------------+---------------+
     |                              VNA                              |
     +---------------+---------------+---------------+---------------+
     |                                                               |
     |                                                               |
     |                                                               |
     |                              HI                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     +---------------+---------------+---------------+---------------+
     |                                                               |
     |                             HHIT                              |
     |                                                               |
     |                                                               |
     +---------------+---------------+---------------+---------------+
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                           Signature                           |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     +---------------+---------------+---------------+---------------+

                     Figure 18: Self Endorsement Binary

                                   TODO

                      Figure 19: Self Endorsement CBOR

B.3.  Broadcast Endorsement

Wiethuechter & Reid       Expires 21 March 2024                [Page 43]
Internet-Draft             DETIM Architecture             September 2023

                      broadcast_endorsement = {
                          scope: {
                              vnb: number,
                              vna: number
                          },
                          evidence: bstr,
                          endorser: {
                              identity: {
                                  hhit: bstr .size 16
                              },
                              signature: {
                                  sig: bstr
                              }
                          }
                      }

                   Figure 20: Broadcast Endorsement CDDL

   Defined by [drip-auth] in a binary format to support Authentication
   over F3411 constrained links.  Used in the DRIP Link format.  A
   required output of registration to a DIME at any level. evidence is a
   binary string of the concatination of a child entities (e.g. a UA)
   HHIT and its associated HI. hhit is of the parent entity (e.g. a
   DIME).

Wiethuechter & Reid       Expires 21 March 2024                [Page 44]
Internet-Draft             DETIM Architecture             September 2023

      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
     +---------------+---------------+---------------+---------------+
     |                              VNB                              |
     +---------------+---------------+---------------+---------------+
     |                              VNA                              |
     +---------------+---------------+---------------+---------------+
     |                                                               |
     |                            HHIT of                            |
     |                             Child                             |
     |                                                               |
     +---------------+---------------+---------------+---------------+
     |                                                               |
     |                                                               |
     |                                                               |
     |                             HI of                             |
     |                             Child                             |
     |                                                               |
     |                                                               |
     |                                                               |
     +---------------+---------------+---------------+---------------+
     |                                                               |
     |                            HHIT of                            |
     |                            Parent                             |
     |                                                               |
     +---------------+---------------+---------------+---------------+
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                           Signature                           |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     +---------------+---------------+---------------+---------------+

                  Figure 21: Broadcast Endorsement Binary

                                   TODO

Wiethuechter & Reid       Expires 21 March 2024                [Page 45]
Internet-Draft             DETIM Architecture             September 2023

                   Figure 22: Broadcast Endorsement CBOR

Appendix C.  DNS Examples

      Author Note: with the proposal to remove solving the issue of
      putting Serial Numbers into DNS from this document, Serial Numbers
      section is removed and part of a new document.

C.1.  Serial Method 1

   @ORIGIN mfr0.uas-sn.arpa
   example1.8 IN URI ( https://example.com/sn/EXAMPLE1 )

C.2.  Serial Method 2

@ORIGIN mfr0.uas-sn.arpa
example2.8 IN DET ( 5 20010033e872f705f3ce91124b677d65 ... "MFR MFR0" MFR08EXAMPLE2 https://example.com/sn/EXAMPLE2 ... active )

@ORIGIN 3.2.f.7.0.f.a.1.3.0.0.1.0.0.2.ip6.arpa
6.5.d.7.7.6.b.4.2.1.1.9.e.c.3.f.5.0 IN PTR example2.8.mfr0.uas-sn.arpa

C.3.  Serial Method 3

@ORIGIN mfr0.uas-sn.arpa
example3.8 IN DET ( 5 20010033e872f70584b1fa2b70421112 ... "MFR MFR0" MFR08EXAMPLE3 https://example.com/sn/EXAMPLE3 ... active )

@ORIGIN 3.2.f.7.0.f.a.1.3.0.0.1.0.0.2.ip6.arpa
2.1.1.1.2.4.0.7.b.2.a.f.1.b.4.8.5.0 IN PTR example3.8.mfr0.uas-sn.arpa

C.4.  Serial Method 4

@ORIGIN mfr0.uas-sn.arpa
example4.8 IN DET ( 5 20010033e872f705ba8af5252a35030e ... "MFR MFR0" MFR08EXAMPLE4 https://example.com/sn/EXAMPLE4 ... active )

@ORIGIN 3.2.f.7.0.f.a.1.3.0.0.1.0.0.2.ip6.arpa
e.0.3.0.5.3.a.2.5.2.5.f.a.8.a.b.5.0 IN PTR example4.8.mfr0.uas-sn.arpa

C.5.  Operator

@ORIGIN 0000.3ffe.2001003.hhit.arpa
ba8af5252a35030e.05.0000.3ffe.2001003.hhit.arpa IN DET ( 5 2001003fff800005ba8af5252a35030e ... "TEST DRIP" null https://example.com/operator/* ... active )

@ORIGIN 0.0.0.8.f.f.f.3.0.0.1.0.0.2.ip6.arpa
e.0.3.0.5.3.a.2.5.2.5.f.a.8.a.b.5.0 IN PTR ba8af5252a35030e.05.0000.3ffe.2001003.hhit.arpa

C.6.  Session ID

Wiethuechter & Reid       Expires 21 March 2024                [Page 46]
Internet-Draft             DETIM Architecture             September 2023

@ORIGIN 0000.3ffe.2001003.hhit.arpa
b6ce935b616306d4.05.0000.3ffe.2001003.hhit.arpa IN DET ( 5 2001003fff800005b6ce935b616306d4 ... "TEST DRIP" null https://example.com/session/* ... active )

@ORIGIN 0.0.0.8.f.f.f.3.0.0.1.0.0.2.ip6.arpa
4.d.6.0.3.6.1.6.b.5.3.9.e.c.6.b.5.0 IN PTR b6ce935b616306d4.05.0000.3ffe.2001003.hhit.arpa

C.7.  Child DIME

RAA:
@ORIGIN 8.f.f.f.3.0.0.1.0.0.2.ip6.arpa
0.0.0 IN NS 0.0.0.8.f.f.f.3.0.0.1.0.0.2.ip6.arpa

HDA:
@ORIGIN 0.0.0.8.f.f.f.3.0.0.1.0.0.2.ip6.arpa
9.6.6.b.b.0.6.a.4.9.3.6.8.4.e.4.5.0 IN PTR 4e486394a60bb669.05.0000.3ffe.2001003.hhit.arpa

@ORIGIN 0000.3ffe.2001003.hhit.arpa
4e486394a60bb669.05.0000.3ffe.2001003.hhit.arpa IN DET ( 5 2001003fff8000054e486394a60bb669 ... "TEST DRIP" null https://example.com/session/* ... active )

Authors' Addresses

   Adam Wiethuechter (editor)
   AX Enterprize, LLC
   4947 Commercial Drive
   Yorkville, NY 13495
   United States of America
   Email: adam.wiethuechter@axenterprize.com

   Jim Reid
   RTFM llp
   St Andrews House
   382 Hillington Road, Glasgow Scotland
   G51 4BL
   United Kingdom
   Email: jim@rfc1035.com

Wiethuechter & Reid       Expires 21 March 2024                [Page 47]