Internet-Draft DETIM Architecture May 2024
Wiethuechter & Reid Expires 2 December 2024 [Page]
drip Working Group
Intended Status:
Standards Track
A. Wiethuechter, Ed.
AX Enterprize, LLC
J. Reid
RTFM llp

DRIP Entity Tag (DET) Identity Management Architecture


This document describes the high level architecture for the registration and discovery of DRIP Entity Tags (DETs) using DNS. Discovery of DETs and related metadata is performed via 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

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 2 December 2024.

Table of Contents

1. Introduction

Registries are fundamental to Unmanned Aircraft System (UAS) Remote ID (RID). Only very limited operational information can be sent via Broadcast RID, 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]).

Such extended information is retrieved from the UAS ID via the use of a DRIP Entity Tag (DET) [RFC9374] which is managed by the DRIP Identity Management Entity (DIME). In this document we assume the DIME belongs to the UAS Service Suppliers (USS) (Appendix A.2 of [RFC9434]) but a DIME can be independent or handled by another entity as well.

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 will be private. As discussed in Section 7 of [RFC9434], Authentication, Attestation, Authorization, Access Control, Accounting, Attribution, and Audit (typically known as AAA) 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 are out of scope for this document.

The intent of the access control requirements 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.

Registration is necessary to guarantee the uniqueness of the DET and thus to ensure the extended information is bound to the UAS ID.

This document creates the DRIP registration and discovery architecture focusing on the DET for UAS at its surrounding ecosystem. Clients in the architecture that can use a DET include 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.

2. General Concept

DETs MUST be registered within the hierarchy to become legitimate. DIME's are the points in the hierarchy that enforce requirements on registration and information access. This document standardizes the basic interactions and methods for registration and lookup to support interoperability based around DETs. Other identifiers and their methods are out of scope for this document.

This document selects the Domain Name System (DNS) as the Public Information Registry for both storing and retrieving public information, such as the public key of DETs and pointers to Private Information Registries. Personally Identifiable Information (PII) is stored in Private Information Registries and MUST be protected through AAA. AAA mechanisms to protect PII is out of scope for this document.

For UAS, a DIME can provide the following registration and lookup services:

  1. personal information (e.g. for pilots and operators)
  2. UAS Serial Number and aircraft physical characteristics
  3. DETs as a Key ID for UAS RID Authentication ([drip-auth])
  4. DETs as a pseudo-anonymous UAS Specific Session ID (UAS ID Type 4)
  5. binding of UAS ID to UTM Operational Intent

A DIME's services are determined by their intended role (Section 4) and policies (both internally and from appropriate authorities). For example, services 1 and 2 can be restricted to non-public access controlled lookups with mandatory registration and 5 to publicly available but access controlled lookups.

For this document only services 3 and 4, as they directly relate to DETs, are detailed. Services 1 and 5 will be talked about conceptually while service 2 is out of scope.

Requirements on the elements of information in registration and lookup (beyond the scope basic interoperability) is out of scope for this document. It is left to appropriate authorities to determine these details along with policy for access. For the UAS use-case this would be the national Civil Aviation Authorities (CAAs).

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].

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

[RFC9374] defines the Hierarchical Host Identity Tag (HHIT) and further specifies an instance of them used for UAS RID called DETs. The HHIT is a 128-bit value that can be represented as an IPv6 address.

As a review, HHITs are comprised of four major components: a Prefix, a Hierarchy ID (HID), a HHIT Suite ID (fixed 8-bits) and an ORCHID Hash. DETs use a 28-bit prefix and 64-bit hash leaving 28-bits for the HID. For UAS RID this HID is further divided into two fields: RAA and HDA, each 14-bits in length. Figure 1 shows this breakdown.

| IPv6 Prefix | Hierarchy ID | HHIT Suite ID | ORCHID Hash |
| (28-bits)   | (28-bits)    | (8-bits)      | (64-bits)   |
             /                \
            /                  \
           /                    \-----------------------------\
          /                                                    \
         /                                                      \
        | Registered Assigning Authority | HHIT Domain Authority |
        | (14-bits)                      | (14-bits)             |
Figure 1: DRIP Entity Tag Breakdown

[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 (Section 5) and can be classified to serve a number of different roles, mapped to levels in the hierarchy, which are detailed in the following subsections.

4.1. Apex

The Apex is the IPv6 prefix portion of the DET associated with it which is assigned by IANA from the special IPv6 address space for ORCHIDs. It serves as the branch point from the larger DNS system in which DETs are defined. The Apex manages all delegations and allocations of RAAs to various parties. The Apex MUST reserve an allocation for itself that it MAY use.

4.1.1. DRIP Apex for UAS RID

For UAS RID the Apex uses IPv6 prefix of 2001:30/28 per [RFC9374]. Allocations of RAAs in this prefix SHOULD be done in contiguous groups of 4. This is to support the nibble reversing of the DET to be placed in DNS (Section 8.1). See Section 11.1 for the RAA allocations.

Values 0 (0x0000) through 3 (0x0003) MUST be reserved for the UAS RID Apex and SHOULD be used to endorse RAA delegations in Endorsements (Section 9). While the individual Apexes can be designated for different purposes they share the same pool of RAAs to be allocated. Such operation would require policy by the administrator of the Apex to avoid simultaneous allocation and is out of scope for this document.

4.2. Registered Assigning Authority (RAA)

An RAA is a business or organization that runs a DIME to register HDAs (Section 4.3). Most are expected to be CAAs (using Section 4.2.1), such as the Federal Aviation Authority (FAA), that then delegate HDAs for use in their National Air Space (NAS). This is does not preclude other entities to operate an RAA if the Apex allows it.


  • MUST provide a set of services to allocate HDAs to organizations
  • MUST have a public policy on what is necessary to obtain an HDA
  • SHOULD provide service level guarantees for DNS operation and registry service
  • SHOULD maintain a DNS zone minimally for discovering HIP RVS servers

All RAA's MUST use the single reserved HDA value 0 (0x0000) for itself to support various functions or services. Other HDA values SHOULD 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 (raa_code + 0, raa_code + 1, raa_code + 2 and raa_code + 3) 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 (by ISO 3166-1) as "user assigned code elements" and do not have specific claimants predefined in the RAA space. Withdrawn and other special codes also do not have predetermined claimants. These values MUST NOT be used for an RAA.

How a CAA handles their allocated values 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.

  • Author Note: get ISO reference for document and for reserved/special allocations. Reference/steal from ENUM document text on delegation procedure. How country code delegations are done through ICAO.
  • Informational Note: A single entity may control more than one NAS (for example LU and BE being covered by and would manage two allocation spaces. How this is claimed and handled is out of scope for this document.

4.2.2. Experimental

The RAA range of 16376 (0x3FF8) to 16383 (0x3FFF), eight (8) RAAs, is allocated to the DRIP working group itself as an experimental range. RAA 16376 is already "in use" with The rest of the range (16377 to 16383) are reserved to be allocated by a designated expert to agencies or organizations that wish to test for a period of time.

  • Author Note: ietf leadership has to choose DE

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 client entities that need DETs. This includes, but is not limited to UA, GCS, UAS Operators and UAS/UTM infrastructure (such as Supplemental Data Service Providers). It SHOULD also provide needed UAS services including those required for HIP-enabled devices (e.g. RVS).

For UAS RID, HDAs can provide any of the following services:

  • registration and public lookup of DETs as a Key ID for Authentication as defined in [drip-auth]
  • registration and access controlled lookup of DETs as a pseudo-anonymous UAS Session ID
  • registration of UAS ID and UTM Operational Intent to bind them together (if allowed by cognizant authority)

An HDA SHOULD maintain a set of RVS servers for UAS clients that may use HIP. This service MUST be discoverable through the DNS zone maintained by the HDA's RAA.

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 for this document.

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.

Interfaces with a specific transport requirement (such as HTTPS) are labeled accordingly. Interfaces not labeled can be implementation specific or proprietary due to co-location of components. For example the interface between the DPA and a Registrar, when delegated, might be Extensional Provisioning Protocol (EPP) [RFC5730] while implementations co-locating these components might use an internal code library. These non-labeled interfaces are out of scope for this document.

| Registering Client |
          | HTTPS
*         |                                                        *
*         |      DRIP Identity Management Entity (DIME)            *
*         |                                                        *
*   ######|#####################################################   *
*   #     |                                                    #   *
*   #  +--o-----------------+                                  #   *
*   #  | DIME               |                                  #   *
*   #  | Provisioning Agent |         Registrar Functions      #   *
*   #  | (DPA)              |                                  #   *
*   #  +--------------------+                                  #   *
*   #                                                          #   *
*   ##############################o#############################   *
*                                 |                                *
*                                 | EPP                            *
*                                 |                                *
*   ##############################o#############################   *
*   #                                                          #   *
*   #  +--------------------+                                  #   *
*   #  | DIME               |                                  #   *
*   #  | Information Agent  |         Registry Functions       #   *
*   #  | (DIA)              |                                  #   *
*   #  +--------------------+                                  #   *
*   #                                                          #   *
*   ######o#########################################o###########   *
*         |                                         |              *
*         |                                         |              *
          |                                         |
          | Registrant Information Service          |
          | (e.g. WHOIS, RDAP, etc.)                | DNS
          |              +---------------+          |
          '--------------o Lookup Client o----------'
Figure 2: DIME Logical Components

5.1. DIME Provisioning Agent (DPA)

The DPA performs the task of vetting information coming from clients wishing to register and then delegates (internally or externally) various items to other components in the DIME. This is the primary component that handles all DRIP related cryptographic operations for incoming registrations to the DIME.

The DPA:

  • MUST have a publicly accessible and discoverable HTTPS interface for clients to register through
  • MUST use a provided interface from a Registrar (Section 5.2)

Specific details of the public HTTPS interface (such as advertisement) is out of scope for this document.

A DPA can be considered an additional specific function to an existing DNS Registrar for DRIP. It MAY be a separate service or entity that interfaces with a DNS Registrar.

5.2. Registrar & Registry

The Registrar and Registry and pre-existing components used in DNS. These components interface the DIME into the DNS hierarchy and thus operation SHOULD follow best common practices, specifically in security (such as running DNSSEC) as appropriate.

Existing functions and interface/protocol specifications for Registrars and Registries are out of scope for this document. However the following references are presented as pointers to material that might be useful: TODO: add list of useful RFCs?

  • 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.

5.3. DIME Information Agent (DIA)

The DIA is the main component handling information egress (via lookup) of the Registry.

The DIA:

  • MUST have an access controlled interface for add/delete/update of information that MAY be publicly available

    • this interface definition is out of scope for this document
  • MUST have an access controlled interface to query for information that MAY be publicly available

    • if this interface is publicly available it MUST use Registration Data Access Protocol (RDAP) ([RFC7480], [RFC9082] and [RFC9083])
    • if this interface is not publicly available its specification is out of scope for this document

Certain information stored, due to policy, may be considered PII and MUST be protected from access using AAA (for example using XACML). See Section 7 for more information.

A DIA can be considered an additional function to an existing DNS Registry for DRIP. It MAY be a separate service or entity that interfaces with a DNS Registry.

6. DET Registration Process

The general process for a registering DET is as follows:

  1. Verify inputs (such as Endorsement(s)) from registering client
  2. DPA checks 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)

Generically a DET can be used as an identifier for any client in UTM and SHOULD be registered to a DIME. For example a CAA may choose to use DETs for its Operators. A data model (such as what is specified in Section 6.1) would be required to define all the information for registration for a given classification of client.

Such specification beyond using DETs as a Session ID and/or Key ID (Section 6.2, Section 6.3 and Section 6.4) is out of scope for this document.

6.1. DET Registration Data Model

The following is the general data model for DET registration data to be sent to the DPA from a client. This model is defined for and used by Section 6.2, Section 6.3 and Section 6.4.

det_registration_info = {
    serial_number: tstr .size 20,  ; ANSI CTA2063-A UAS Serial Number
    uas_id: bstr .size 20,  ; UAS ID per ASTM F3411-22a Basic ID Message
    uas_id_type: 0..15,  ; UAS ID Type per ASTM F3411-22a
    ? self_endorsement: bstr .size 120,
    ? key_binding,
    ? utm_binding,
    * tstr => any
utm_binding = (
    utm_id: bstr .size 16,  ; Operational Intent (UUIDv4)
    utm_source: tstr  ; URI to USS with Operational Intent
key_binding = (
    key_id: bstr,
    key: bstr
UAS ID Type and UAS ID:
defined per ASTM [F3411]. See Section 6.1.1 for handling specific instructions during registration.
UAS Serial Number:
defined per [CTA2063A]. Other UAS Serial Number formats (considered legacy) are out of scope for this document.
UTM Assigned ID:
also known as an Operational Intent, defined per ADD-UTM-REF and ASTM [F3411] as a UUIDv4. Part of the UTM Binding group which also includes the source URI of the Operational Intent.
Key ID:
part of the Key Binding group which also includes a raw key value.
Self Endorsement:
defined per Section 9 and Appendix D.1. See Section 6.1.2 for handling specific instructions during registration.

It is RECOMMENDED that the information above is signed over in some way to ensure integrity of the registration data. The recommended way to do this is with a Endorsement (Section 9). Another way is with a JWT[RFC7519] or CWT [RFC8392] using the clients key.

Other data elements MAY be added to this model. A DIME MUST have a public API detailing additional elements expected for their implementations. These elements and reference is out of scope for this document.

6.1.1. UAS ID Handling

The uas_id_type field MUST be set to same UAS ID Type in the ASTM [F3411] Basic ID Message to ensure proper decoding of the uas_id field.

The uas_id field MUST be set with the octets found in the ASTM [F3411] Basic ID Message UAS ID field. By using identical contents of the Basic ID Message the Specific Session ID Type octet (the first octet in the UAS ID when using UAS ID Type is 0x4) is preserved. When a DET is used a Session ID, the value of this first octet MUST be 0x01.

6.1.2. Self Endorsement

The self_endorsement is included when a DET is used either as a Session ID (in uas_id) or for Authentication (in key_id).

The value is verified by the DPA and its contents used to generate a Broadcast Endorsement for use in [drip-auth] and put into DNS.

6.1.3. Service Tuple

Five critical pieces of information are required to provide the services listed in Section 2 that make a tuple. These are: UAS ID, UAS ID Type, UAS Serial Number, Key ID and UTM Assigned ID. The UAS ID, UAS ID Type and UAS Serial Number fields are mandatory and MUST NOT be null for entry as defined.

This tuple encodes the services that the specific registration is being used. A few examples can be seen in the table below.

Table 1
Service UAS ID UAS ID Type UAS Serial Number Key ID UTM Assigned ID
DET Authentication TEST3ABC 0x1 TEST3ABC DET -
DET Session ID 0x01 + DET 0x4 TEST3ABC - -
DET Session ID + Authentication 0x01 + DET 0x4 TEST3ABC DET -

As this document focuses on DETs exclusively the use of the Key ID using other cryptographic identifiers and how to distinguish between them (such as how UAS ID and UAS ID Type is used) is out of scope of this document.

6.2. DET Authentication

For Authentication use of a DET, registration requires the following additional data elements: key_id, self_endorsement. Section 6.1.2 MUST be followed.

6.3. DET Session ID

For the registration of a DET as a Session ID the client is typically the UAS. The mechanisms of how the UAS generates a DET are out of scope for this document.

For Session ID use of a DET, registration requires the following additional data elements: self_endorsement. Both Section 6.1.1 and Section 6.1.2 MUST be followed.

Optionally a binding between a DET and a UTM Session ID can be made by providing the information of the UTM side using utm_id and utm_source. The support of this is based on CAA policy and is out of scope for this document.

6.4. DET Session ID & Authentication

For Session ID & Authentication use of a DET, registration requires the following additional data elements: key_id, self_endorsement. Both Section 6.1.1 and Section 6.1.2 MUST be followed.

7. Differentiated Access Process

Per [RFC9434] all information classified as private 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.

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].

DIMEs MUST be responsible for the operation of the DNS-related infrastructure for domain names under DRIP. It MAY chose to run that infrastructure directly or outsource it to competent third parties or some combination of the two.

DIMEs 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. National policy and regulations will define how long DNS data are stored or archived. These are all National Matters where national law/regulation prevail ensuring DRIP complies with national law and regulation since these are matters of national sovereignty.

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.

Static UAS specific information that is publicly available MAY also be stored in DNS but is out of scope for this document.

For DRIP, IANA has agreed to act as the Apex at least initially (see Section 11.1 for more details). 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. The Apex 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.

8.1. DRIP Entity Tags

The REQUIRED mechanism is to place any information into 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 - the corresponding reverse domain - SHOULD be under the administrative control of the Apex. In addition to the DNS infrastructure for, 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 HHIT resource record (Appendix A) 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, HHIT, TLSA, URI, or PTR RRTypes.

9. Endorsements

DRIP Endorsements are defined in a CDDL [RFC8610] structure (Figure 3) that can be encoded to CBOR, JSON or as a binary blob by concatenating values. 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.

endorsement = array)
e-data = [e-type, scope, ? $$evidence, $$endorser, $$signature]

e-type = uint .size(2)
scope = (vnb: time, vna: time, ? $$scope-ext)

$$endorser //= (hhit,)
$$endorser //= (hhit, eddsa25519-hi,)
$$endorser //= (eddsa25519-hi,)
hhit = #6.54(bstr .size(16))
eddsa25519-hi = bstr .size(32)

$$signature = (eddsa25519-sig,)
eddsa25519-sig = bstr .size(64)
Figure 3: Endorsement CDDL
Endorsement Type:
a 16-bit value used to hint at the content of the $$evidence group. Four special values (1 through 4) map to the SAM Type of the Authentication framing in [drip-auth], allowing the 16-bit value to be excluded from the Endorsement structure. See Section 11.2.2 for more details.
Scope & Scope Extensions:
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 using the $$scope-ext socket group.
socket group containing a set claims. The content and order of claims is specified explicitly for each e-type.
socket group 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). The content and ordering is specified explicitly for each e-type.
socket group containing the signature data for the Endorsement. The content and ordering is specified explicitly for each e-type. Signatures MUST be generated using the preceding sections (except for e-type) in their binary forms (i.e. as a concatenated bytestring of values) rather than their CBOR encoding.

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

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). 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.

  • Authors 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

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.

10.3. Examples

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

10.4. Alternative Certificate Encoding

The CBOR Encoded X.509 Certificates (C509 Certificates) [cbor-cert] provides a standards-based approach to reduce the size of X.509 certificates both on-the-wire and in storage. The PKI-Lite RAA certificate example in Appendix B.2 is 331 bytes. The matching C509 certificate is 183 bytes. This sort of difference may have significant impact both on UAS storage requirements and over-the-air transmission impact.

C509 provides two approaches for encoding X.509:

  1. An invertible CBOR re-encoding of DER encoded X.509 certificates [RFC5280], which can be reversed to obtain the original DER encoded X.509 certificate.
  2. Natively signed C509 certificates, where the signature is calculated over the CBOR encoding instead of over the DER encoding as in 1. This removes the need for ASN.1 and DER parsing and the associated complexity but they are not backwards compatible with implementations requiring DER encoded X.509.

The invertible CBOR encoding may be sufficient for most needs. The CBOR objects clearly indicate which approach was used, so that the receiver can properly process the C509 object. For interoperability in DRIP, it is recommended that invertible CBOR encoding be used.

Using the invertible CBOR encoding is achieved through in-line libraries that convert in the desired direction. Since it is not expected that DNS protocols to implement this conversion, the HHIT RR SHOULD contain the normal X.509 DER encoding. The CBOR encoding MAY be used, but operational experience will be needed to see if there are measurable gains in doing so.

11. IANA Considerations

11.1. Management of DRIP Apex

A discussion between the authors of this document, DRIP AD and IANA was held during IETF 118. Those present were:

  • Eric Vyncke (AD of DRIP WG)
  • Bob Moskowitz
  • Jim Ried (Author of this RFC)
  • Adam Wiethuechter (Editor of this RFC)
  • Kim Davies (IANA)

IANA agreed that they would be willing to manage the Apex for DRIP until the desired Apex manager, International Civil Aviation Organization (ICAO), is ready. This is expected to be in the next 5 years due to ICAO process. The hand-over to ICAO is TBD at that time but various options are available.

Further discussion of the SLA required to RAAs by IANA is and other requirements to IANA are TBD.

11.2. IANA DRIP Registry

11.2.1. DRIP RAA Allocations

This document requests a new registry for RAA Allocations under the DRIP registry group.

RAA Allocations:
a 14-bit value that is allocated in groups of 4. Future additions to this registry are to be made through Expert Review (Section 4.5 of [RFC8126]). The following values/ranges are defined:
Table 2
RAA Value(s) Status Allocation Reference
0 - 3 Allocated UAS RID (DRIP) Apex This RFC (Section 4.1.1)
4 - 3999 Allocated ISO 3166-1 Countries This RFC (Section 4.2.1)
4000 - 16375 Reserved N/A N/A
16375 - 16383 Allocated DRIP WG (Experimental Use) This RFC (Section 4.2.2)

The mapping between ISO 3166-1 Numeric Numbers and RAAs can be found as a CSV file here: TODO.

11.2.2. Endorsement Types

This document requests a new registry for Endorsement Type under the DRIP registry group.

Endorsement Type:
A 16-bit value to provide hinting of the contents of other sections of an Endorsement. Future additions to this registry are to be made through Specification Required (Section 4.3 of [RFC8126]) for values 0x0000 to 0xEFFF and First Come First Served (Section 4.4 of [RFC8126]) for the values 0xF000 to 0xFFFF. The following values are defined:
Table 3
Value Endorsement Type Reference
0 Self-Endorsement This RFC (Appendix D.1)
1 Broadcast Endorsement This RFC (Appendix D.2)
2 Wrapper This RFC (Appendix D.3)
3 Manifest This RFC (Appendix D.4)
4 Frame This RFC (Appendix D.5)

To register an e-type the following MUST be provided in CDDL for review:

  • Additions to scope group using $$scope-ext
  • Specific group contents of $$evidence
  • Specific group contents of $$endorser
  • Specific group contents of $$signature

11.2.3. HHIT Type

This document requests a new registry for HHIT Type under the DRIP registry group.

HHIT Type:
numeric, 16-bit, field of the HHIT RR to encode the HHIT Type. Future additions to this registry are to be made through Expert Review (Section 4.5 of [RFC8126]). The following values are defined:
Table 4
Value Type Reference
0 Not Defined This RFC
1 DRIP Identity Management Entity (DIME) This RFC
2 Apex This RFC
3 Registered Assigning Authority (RAA) This RFC
4 HHIT Domain Authority (HDA) This RFC
5 DIME Provisioning Agent (DPA) This RFC
6 DIME Information Agent (DIA) This RFC
7 Name Server (NS) This RFC
8 Registration Data Directory Service (RDDS) This RFC
9 ISO 3166-1 Numeric Nation (INN) This RFC
10 - 15 Reserved  
16 Endpoint Entity (EE) [drip-dki]
17 Issuer CA [drip-dki]
18 Authentication CA [drip-dki]
19 Uncrewed Aircraft (UA) This RFC
20 Ground Control Station (GCS) This RFC
21 Uncrewed Aerial System (UAS) This RFC
22 Remote Identification (RID) Module This RFC
23 Pilot This RFC
24 Operator This RFC
25 Discovery & Synchronization Service (DSS) This RFC
26 UAS Service Supplier (USS) This RFC
27 Network RID Service Provider (SP) This RFC
28 Network RID Display Provider (DP) This RFC
29 Supplemental Data Service Provider (SDSP) This RFC
30 - 65535 Reserved  

11.2.4. HHIT Status

This document requests a new registry for HHIT Status under the DRIP registry group.

HHIT Status:
numeric, 8 bit, field of the HHIT RR to encode the HHIT Status. Future additions to this registry are to be made through Expert Review (Section 4.5 of [RFC8126]). The following values are defined:
Table 5
Value Status Description Reference
0 Inactive Default when accepted by DIME This RFC
1 Active Set when in use This RFC
2 Expired Set when past VNA This RFC
3 Deprecated Set when no longer in use (but not expired) This RFC

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.

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 [FAA-RID-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.

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. Public Key Exposure

DETs are built upon asymmetric keypairs. As such the public key must be revealed to enable clients to perform signature verifications.

While unlikely the forging of a corresponding private key is possible if given enough time (and computational power). As such it is RECOMMENDED that the public key for any DET not be exposed in DNS (using the HIP RR) until it is required.

Optimally this requires the UAS somehow signal the DIME that a flight using a Specific Session ID is underway or complete. It may also be facilitated under UTM if the USS (which may or may not be a DIME) signals when a given operation using a Session ID goes active.

14. 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.

15. References

15.1. Normative References

Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <>.
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <>.
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, , <>.
Card, S., Ed., Wiethuechter, A., Moskowitz, R., and A. Gurtov, "Drone Remote Identification Protocol (DRIP) Requirements and Terminology", RFC 9153, DOI 10.17487/RFC9153, , <>.
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, , <>.
Card, S., Wiethuechter, A., Moskowitz, R., Zhao, S., Ed., and A. Gurtov, "Drone Remote Identification Protocol (DRIP) Architecture", RFC 9434, DOI 10.17487/RFC9434, , <>.

15.2. Informative References

Mattsson, J. P., Selander, G., Raza, S., Höglund, J., and M. Furuhed, "CBOR Encoded X.509 Certificates (C509 Certificates)", Work in Progress, Internet-Draft, draft-ietf-cose-cbor-encoded-cert-09, , <>.
"ANSI/CTA 2063-A Small Unmanned Aerial Systems Numbers", , <>.
Huque, S. and V. Dukhovni, "TLS Client Authentication via DANE TLSA records", Work in Progress, Internet-Draft, draft-ietf-dance-client-auth-05, , <>.
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-49, , <>.
Moskowitz, R. and S. W. Card, "The DRIP DET public Key Infrastructure", Work in Progress, Internet-Draft, draft-moskowitz-drip-dki-09, , <>.
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-c2-14, , <>.
ASTM International, "Standard Specification for Remote ID and Tracking", ASTM F3411-22A, DOI 10.1520/F3411-22A, , <>.
"Notice of Proposed Rule Making on Remote Identification of Unmanned Aircraft Systems", .
Thomson, S. and C. Huitema, "DNS Extensions to support IP version 6", RFC 1886, DOI 10.17487/RFC1886, , <>.
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, , <>.
Hollenbeck, S., "Extensible Provisioning Protocol (EPP)", STD 69, RFC 5730, DOI 10.17487/RFC5730, , <>.
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, , <>.
Ljunggren, F., Eklund Lowinder, AM., and T. Okubo, "A Framework for DNSSEC Policies and DNSSEC Practice Statements", RFC 6841, DOI 10.17487/RFC6841, , <>.
Newton, A., Ellacott, B., and N. Kong, "HTTP Usage in the Registration Data Access Protocol (RDAP)", STD 95, RFC 7480, DOI 10.17487/RFC7480, , <>.
Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token (JWT)", RFC 7519, DOI 10.17487/RFC7519, , <>.
Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, , <>.
Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig, "CBOR Web Token (CWT)", RFC 8392, DOI 10.17487/RFC8392, , <>.
Hollenbeck, S. and A. Newton, "Registration Data Access Protocol (RDAP) Query Format", STD 95, RFC 9082, DOI 10.17487/RFC9082, , <>.
Hollenbeck, S. and A. Newton, "JSON Responses for the Registration Data Access Protocol (RDAP)", STD 95, RFC 9083, DOI 10.17487/RFC9083, , <>.

Appendix A. HHIT Resource Record

This appendix is normative.

The HHIT Resource Record is a metadata record for various bits of HHIT specific information that isn't available in the pre-existing HIP RR Type. It is encoded as a CBOR array.

rr = array)
rr_data= [hhit, type, status, abbreviation, endorsements]
hhit = #6.54(bstr .size(16))
type = uint .size(2)
status = uint .size(1)
abbreviation = tstr .size(15)
endorsements = [1* endorsement]  ; MUST be in e-type order
uris = [* #6.32]
Figure 4: Resource Record Wire CDDL
<domain> HHIT IN ( HHIT TYPE STATUS ABBREV [Endorsement(s)] [URI(s)])
Figure 5: Resource Record Text CDDL
This field is two octets with values defined in Section 11.2.3. It is envisioned that there may be many types of HHITs in use. In some cases it may be helpful to understand the HHITs role in the ecosystem like described in [drip-dki].
This field is a single byte with values defined in Section 11.2.4. A HHIT can go through various states during its life-cycle in the ecosystem. It is helpful for a querant to understand the current status as a further requirement for verification.
This field is meant to provide an abbreviation to the HID structure for display devices. The specific contents of this field are not defined here, but a recommendation/example can be found in Appendix B.
This field is a list of CBOR encoded Endorsements in e-type order. It MUST included at least one Broadcast Endorsement (Appendix D.2). A special case for the Apex is that the Broadcast Endorsement is filled with its own DET and HI as evidence (i.e. a self-signed Broadcast Endorsement).
This field is a list of URIs that can be used for the given HHIT to obtain information. URIs are encoded in the CBOR.

Appendix B. HID Abbreviation Recommendation

This appendix is informative.

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 should not be used and be replaced with either underscores (_) or dashes (-).

The concatenation of {RAA Abbreviation} and {HDA Abbreviation} with a space between them can be what fills in the HID field of the HHIT RR in Appendix A.

For RAAs allocated in the ISO range Section 4.2.1, the RAA abbreviation should be set to the ISO 3166-1 country code (either Alpha-2 or Alpha-3). A common abbreviation for an RAAs four allocated RAA values are out of scope. Other documents such as [drip-dki] may have more specific recommendations or requirements.

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 when using this form.

Appendix C. DETs as Fully Qualified Domain Names

This appendix is informative.

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

DET: 2001:0030:0280:1405:c465:1542:a33f:dc26
ID: c4651542a33fdc26
OGA: 05
HID: 0028014
HDA: 0014
RAA: 000a
Prefix: 2001003

Appendix D. DRIP Endorsements for UAS

This appendix is normative.

D.1. Self Endorsement

; e-type=0, Self Endorsement
$$evidence //= (eddsa25519-hi,)
$$endorser //= (hhit,)
$$signature = (eddsa25519-sig,)
Figure 6: Self Endorsement CDDL

Used during registration process as an input. $$evidence contains the HI of the endorser. $$endorser contains the HHIT of the endorser. $$signature contains the EdDSA25519 signature.

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 7: Self Endorsement Binary

D.2. Broadcast Endorsement

; e-type=1, SAM Type=1, Broadcast Endorsement
$$evidence //= (hhit, eddsa25519-hi,)
$$endorser //= (hhit,)
$$signature = (eddsa25519-sig,)
Figure 9: Broadcast Endorsement CDDL

Defined by [drip-auth] in a binary format to support Authentication over ASTM [F3411] constrained links. Used in the DRIP Link format. A required output of registration to a DIME at any level.

$$evidence are the child entities (e.g. a UA) DET/HHIT and its associated HI. $$endorser contains the HHIT of the parent entity (e.g. DIME) as the endorser. $$signature contains the EdDSA25519 signature.

Note that the Endorsement Type (e-type) field is the same value as the SAM Type allocated to DRIP (i.e. the value 1). As such for DRIP Authentication the e-type field is not encoded into the binary form and is instead handled by the SAM Type of the Authentication framing.

 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 10: Broadcast Endorsement Binary

D.3. Wrapper Endorsement

; e-type=2, SAM Type=2, Wrapper Endorsement
$$evidence //= (*4 astm-message,)
$$endorser //= (hhit,)
$$signature = (eddsa25519-sig,)
astm-message = bstr .size(25)
Figure 12: Wrapper Endorsement CDDL

D.4. Manifest Endorsement

; e-type=3, SAM Type=3, Manifest Endorsement
$$evidence //= (3*11 manifest-hash,)
$$endorser //= (hhit,)
$$signature = (eddsa25519-sig,)
manifest-hash = bstr .size(8)
Figure 15: Manifest Endorsement CDDL

D.5. Frame Endorsement

; e-type=4, SAM Type=4, Frame Endorsement
$$evidence //= (frame-type, frame-data,)
$$endorser //= (hhit,)
$$signature = (eddsa25519-sig,)
frame-type = uint .size(1)
frame-data = bstr .size(1..111)
Figure 18: Frame Endorsement CDDL

Appendix E. DNS Examples

This appendix is informative.

E.1. Operator

( 2001003fff800005ba8af5252a35030e 0 1 "TEST DRIP" "" ... )
( 5 2001003fff800005ba8af5252a35030e ... )
(* )

E.2. Session ID

4.d. IN DET
( 2001003fff800005b6ce935b616306d4 0 1 "TEST DRIP" "" ... )
4.d. IN HIP
( 5 2001003fff800005b6ce935b616306d4 ... )
4.d. IN URI
(* )

E.3. Child DIME

0.0.0 IN NS

9.6.6.b.b.0.6.a. IN DET
( 2001003fff8000054e486394a60bb669 0 1 "TEST DRIP" "" ... )
9.6.6.b.b.0.6.a. IN HIP
( 5 2001003fff8000054e486394a60bb669 ... )
9.6.6.b.b.0.6.a. IN URI
(* )

Authors' Addresses

Adam Wiethuechter (editor)
AX Enterprize, LLC
4947 Commercial Drive
Yorkville, NY 13495
United States of America
Jim Reid
RTFM llp
St Andrews House
382 Hillington Road, Glasgow Scotland
G51 4BL
United Kingdom