drip Working Group A. Wiethuechter, Ed. Internet-Draft AX Enterprize, LLC Intended status: Standards Track J. Reid Expires: 3 October 2024 RTFM llp 1 April 2024 DRIP Entity Tag (DET) Identity Management Architecture draft-ietf-drip-registries-15 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 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 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 3 October 2024. Copyright Notice Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved. Wiethuechter & Reid Expires 3 October 2024 [Page 1] Internet-Draft DETIM Architecture April 2024 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. General Concept . . . . . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1. Required Terminology . . . . . . . . . . . . . . . . . . 5 3.2. Additional Definitions . . . . . . . . . . . . . . . . . 5 3.3. Text Conventions . . . . . . . . . . . . . . . . . . . . 6 4. DIME Roles . . . . . . . . . . . . . . . . . . . . . . . . . 6 4.1. Apex . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.1.1. DRIP Apex for UAS RID . . . . . . . . . . . . . . . . 7 4.2. Registered Assigning Authority (RAA) . . . . . . . . . . 7 4.2.1. ISO 3166-1 Numeric Nations (INN) . . . . . . . . . . 8 4.2.2. Experimental . . . . . . . . . . . . . . . . . . . . 8 4.3. Hierarchial HIT Domain Authority (HDA) . . . . . . . . . 8 5. DIME Architecture . . . . . . . . . . . . . . . . . . . . . . 9 5.1. DRIP Provisioning Agent (DPA) . . . . . . . . . . . . . . 10 5.2. Registry & Name Server (NS) . . . . . . . . . . . . . . . 11 5.3. DRIP Information Agent (DIA) & Registration Data Directory Service (RDDS) . . . . . . . . . . . . . . . . . . . . . 11 6. DET Registration Process . . . . . . . . . . . . . . . . . . 12 6.1. DET Registration Data Model . . . . . . . . . . . . . . . 13 6.1.1. UAS ID Handling . . . . . . . . . . . . . . . . . . . 14 6.1.2. Self Endorsement . . . . . . . . . . . . . . . . . . 15 6.1.3. Service Tuple . . . . . . . . . . . . . . . . . . . . 15 6.2. DET Authentication . . . . . . . . . . . . . . . . . . . 16 6.3. DET Session ID . . . . . . . . . . . . . . . . . . . . . 16 6.4. DET Session ID & Authentication . . . . . . . . . . . . . 16 7. Differentiated Access Process . . . . . . . . . . . . . . . . 16 8. DRIP in the Domain Name System . . . . . . . . . . . . . . . 17 8.1. DRIP Entity Tags . . . . . . . . . . . . . . . . . . . . 18 9. Endorsements . . . . . . . . . . . . . . . . . . . . . . . . 19 10. X.509 Certificates . . . . . . . . . . . . . . . . . . . . . 20 10.1. Certificate Policy and Certificate Stores . . . . . . . 20 10.2. Certificate Management . . . . . . . . . . . . . . . . . 22 10.3. Examples . . . . . . . . . . . . . . . . . . . . . . . . 22 10.4. Alternative Certificate Encoding . . . . . . . . . . . . 22 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23 11.1. Management of DRIP Apex . . . . . . . . . . . . . . . . 23 Wiethuechter & Reid Expires 3 October 2024 [Page 2] Internet-Draft DETIM Architecture April 2024 11.2. IANA DRIP Registry . . . . . . . . . . . . . . . . . . . 23 11.2.1. DRIP RAA Allocations . . . . . . . . . . . . . . . . 23 11.2.2. Endorsement Types . . . . . . . . . . . . . . . . . 24 11.2.3. HHIT Type . . . . . . . . . . . . . . . . . . . . . 25 11.2.4. HHIT Status . . . . . . . . . . . . . . . . . . . . 27 12. Security Considerations . . . . . . . . . . . . . . . . . . . 27 12.1. Key Rollover & Federation . . . . . . . . . . . . . . . 27 12.2. DET Generation . . . . . . . . . . . . . . . . . . . . . 27 13. Public Key Exposure . . . . . . . . . . . . . . . . . . . . . 28 14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 29 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 29 15.1. Normative References . . . . . . . . . . . . . . . . . . 29 15.2. Informative References . . . . . . . . . . . . . . . . . 29 Appendix A. HHIT Resource Record . . . . . . . . . . . . . . . . 32 Appendix B. HID Abbreviation Recommendation . . . . . . . . . . 33 Appendix C. DETs as Fully Qualified Domain Names . . . . . . . . 33 Appendix D. DRIP Endorsements for UAS . . . . . . . . . . . . . 34 D.1. Self Endorsement . . . . . . . . . . . . . . . . . . . . 34 D.2. Broadcast Endorsement . . . . . . . . . . . . . . . . . . 35 D.3. Wrapper Endorsement . . . . . . . . . . . . . . . . . . . 38 D.4. Manifest Endorsement . . . . . . . . . . . . . . . . . . 38 D.5. Frame Endorsement . . . . . . . . . . . . . . . . . . . . 38 Appendix E. DNS Examples . . . . . . . . . . . . . . . . . . . . 39 E.1. Operator . . . . . . . . . . . . . . . . . . . . . . . . 39 E.2. Session ID . . . . . . . . . . . . . . . . . . . . . . . 39 E.3. Child DIME . . . . . . . . . . . . . . . . . . . . . . . 39 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40 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, Wiethuechter & Reid Expires 3 October 2024 [Page 3] Internet-Draft DETIM Architecture April 2024 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 when generated are only "proposed" and 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. For UAS, a DIME can provide the following congruent registration and lookup services: 1. personal information (e.g. for pilots and operators) Wiethuechter & Reid Expires 3 October 2024 [Page 4] Internet-Draft DETIM Architecture April 2024 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 cognizant 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 cognizant authorities to determine these details along with policy for access. For the UAS use-case this is 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]. Wiethuechter & Reid Expires 3 October 2024 [Page 5] Internet-Draft DETIM Architecture April 2024 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. 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. Wiethuechter & Reid Expires 3 October 2024 [Page 6] Internet-Draft DETIM Architecture April 2024 4.1. Apex The Apex is the owner of 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 manages the IPv6 prefix of 2001:30/28. 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 contemplated to be CAAs (using Section 4.2.1), 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 * MUST have a public policy on what is necessary to obtain an HDA * SHOULD maintain a DNS zone minimally for discovering HIP RVS servers All RAA's MUST have a 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. Wiethuechter & Reid Expires 3 October 2024 [Page 7] Internet-Draft DETIM Architecture April 2024 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. 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. Informational 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. 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 driptesting.org. The rest of the range (16377 to 16383) are reserved to be allocated by the DRIP experts to agencies or organizations that wish to test for a period of time. 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: Wiethuechter & Reid Expires 3 October 2024 [Page 8] Internet-Draft DETIM Architecture April 2024 * 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. How this is done and scales to the potentially millions of customers are outside the scope of this document. 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 Registry/Name Server, when delegated, might be Extensional Provisioning Protocol (EPP) [RFC5730] (due to Registry/Name Server requirements) while implementations co- locating these components might use an internal code library. These non-labeled interfaces are out of scope for this document. Wiethuechter & Reid Expires 3 October 2024 [Page 9] Internet-Draft DETIM Architecture April 2024 +--------------------+ | Registering Client | +---------o----------+ | | HTTPS | **********|********************************************************* * | DRIP Identity Management Entity (DIME) * * | * * +------o-------+ +-------------+ +--------------+ * * | DRIP | | | | | * * | Provisioning o---------o | | | * * | Agent (DPA) | | | | | * * +-------o------+ | | | | * * | | | | | * * | | DRIP | | Registration | * * | | Information o------o Data | * * | | Agent (DIA) | | Directory | * * | | | | Service | * * +-------o----------+ | | | (RDDS) | * * | Registry | | | | | * * | / | | | | | * * | Name Server (NS) | | | | | * * +------o-----------+ +-----o-------+ +--------------+ * * | | * * | | * **********|***********************|********************************* | | | TCP/UDP | RDAP | | | +-------o-------+ '---------------o Lookup Client | +---------------+ 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 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 Wiethuechter & Reid Expires 3 October 2024 [Page 10] Internet-Draft DETIM Architecture April 2024 * MUST use a provided interface from a DRIP Information Agent (Section 5.3) * MUST use a provided interface from a Registry/Name Server (Section 5.2) Specific details of the public HTTPS interface (such as advertisement) is out of scope for this document. 5.2. Registry & Name Server (NS) The Registry & Name Server component handles all the required DNS based requirements of the DIME to function. This includes the registration and maintenance of various DNS Resource Records used in public lookups. The Registry: * MUST provide an interface (for example EPP) for management of DNS functions * MUST provide a standard DNS query interface The detailed specification of either interface is out of scope for this document. The Registry is the component that interfaces the DIME into the DNS hierarchy and thus operation SHOULD follow best common practices, specifically in security (such as running DNSSEC) as appropriate. Specific instruction for operating a Registry & Name Server is 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. DRIP Information Agent (DIA) & Registration Data Directory Service (RDDS) The DIA is the main component handling information ingress (via registration) and egress (via lookup) of the RDDS. The DIA: Wiethuechter & Reid Expires 3 October 2024 [Page 11] Internet-Draft DETIM Architecture April 2024 * 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 within the RDDS, 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. The interface between a DIA and an RDDS is out of scope for this document. 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. Wiethuechter & Reid Expires 3 October 2024 [Page 12] Internet-Draft DETIM Architecture April 2024 In the following subsections an abbreviated form of Figure 2 seen below in Figure 3 uses co-located components to describe the flow of information. Each section gives specific example details for the components, interfaces and data elements. Each section has an associated appendix (Appendix E) containing DNS examples. +----------+ | Client | +--o---o---+ | ^ (1,2) | | (5) | | *******|***|***************************** * | | DIME * * | | * * v | +----------+ * * +--o---o--+ | | * * | DPA (2) o--------->o | * * +----o----+ (4) | | * * | | | * * | (3) | DIA/RDDS | * * v | | * * +----o--------+ | | * * | Registry/NS | | | * * +-------------+ | | * * +----------+ * * * ***************************************** Figure 3: Example Registration Process 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. Wiethuechter & Reid Expires 3 October 2024 [Page 13] Internet-Draft DETIM Architecture April 2024 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 ? key_id: bstr, ? self_endorsement: bstr .size 120, ? utm_binding, * tstr => any } utm_binding = ( utm_id: bstr .size 16, ; Operational Intent (UUIDv4) utm_source: tstr ; URI to USS with Operational Intent ) 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. 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. A recommended way to do this 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. Wiethuechter & Reid Expires 3 October 2024 [Page 14] Internet-Draft DETIM Architecture April 2024 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. +================+==========+========+============+=====+==========+ | Service | UAS ID | UAS ID | UAS Serial | Key | UTM | | | | Type | Number | ID | Assigned | | | | | | | ID | +================+==========+========+============+=====+==========+ | DET | TEST3ABC | 0x1 | TEST3ABC | DET | - | | Authentication | | | | | | +----------------+----------+--------+------------+-----+----------+ | DET Session ID | 0x01 + | 0x4 | TEST3ABC | - | - | | | DET | | | | | +----------------+----------+--------+------------+-----+----------+ | DET Session ID | 0x01 + | 0x4 | TEST3ABC | DET | - | | + | DET | | | | | | Authentication | | | | | | +----------------+----------+--------+------------+-----+----------+ Table 1 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. Wiethuechter & Reid Expires 3 October 2024 [Page 15] Internet-Draft DETIM Architecture April 2024 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. Wiethuechter & Reid Expires 3 October 2024 [Page 16] Internet-Draft DETIM Architecture April 2024 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. Wiethuechter & Reid Expires 3 October 2024 [Page 17] Internet-Draft DETIM Architecture April 2024 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. Author Note: proposal for a UAS RR that is a CBOR map of static UAS data elements (UAS ID, UAS Type, Self Description, etc.) 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 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 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. Wiethuechter & Reid Expires 3 October 2024 [Page 18] Internet-Draft DETIM Architecture April 2024 9. Endorsements DRIP Endorsements are defined in a CDDL [RFC8610] structure (Figure 4) 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. 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. endorsement = 6.xxx(e-data: 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 4: Endorsement CDDL Endorsement Type: a 16-bit value used to hint at the content of the $$evidence group. Four special values (1 through 4) map to the SAM Type of the Authentication framing in [drip-auth], allowing the 16-bit value to be excluded from the Endorsement structure. See Section 11.2.2 for more details. Scope & Scope Extensions: The scope section is more formally "the Wiethuechter & Reid Expires 3 October 2024 [Page 19] Internet-Draft DETIM Architecture April 2024 scope of validity of the endorsement". The scope can come in various forms but MUST always have a "valid not before" (vnb) and "valid not after" (vna) timestamps. Other forms of the scope could for example be a 4-dimensional volume definition. This could be in raw latitude, longitude, altitude pairs or may be a URI pointing to scope information. Additional scope fields are out of scope for this document and should be defined for specific Endorsement structures if they are desired using the $$scope-ext socket group. Evidence: socket group containing a set claims. The content and order of claims is specified explicitly for each e-type. Endorser: 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. Signature: 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. Wiethuechter & Reid Expires 3 October 2024 [Page 20] Internet-Draft DETIM Architecture April 2024 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. Wiethuechter & Reid Expires 3 October 2024 [Page 21] Internet-Draft DETIM Architecture April 2024 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. Wiethuechter & Reid Expires 3 October 2024 [Page 22] Internet-Draft DETIM Architecture April 2024 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 (https://www.iana.org/assignments/drip/ drip.xhtml). RAA Allocations: a 14-bit value that is allocated in groups of 4. Wiethuechter & Reid Expires 3 October 2024 [Page 23] Internet-Draft DETIM Architecture April 2024 Future additions to this registry are to be made through Expert Review (Section 4.5 of [RFC8126]). The following values/ranges are defined: +==============+===========+=====================+=================+ | 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 | This RFC | | | | Countries | (Section 4.2.1) | +--------------+-----------+---------------------+-----------------+ | 4000 - 16375 | Reserved | N/A | N/A | +--------------+-----------+---------------------+-----------------+ | 16375 - | Allocated | DRIP WG | This RFC | | 16383 | | (Experimental Use) | (Section 4.2.2) | +--------------+-----------+---------------------+-----------------+ Table 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 (https://www.iana.org/assignments/drip/ drip.xhtml). 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: Wiethuechter & Reid Expires 3 October 2024 [Page 24] Internet-Draft DETIM Architecture April 2024 +=======+=======================+=========================+ | 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) | +-------+-----------------------+-------------------------+ Table 3 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 (https://www.iana.org/assignments/drip/drip.xhtml). 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: +=========+============================================+============+ | 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 | +---------+--------------------------------------------+------------+ Wiethuechter & Reid Expires 3 October 2024 [Page 25] Internet-Draft DETIM Architecture April 2024 | 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 - | Reserved | | | 15 | | | +---------+--------------------------------------------+------------+ | 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 - | Reserved | | | 65535 | | | +---------+--------------------------------------------+------------+ Table 4 Wiethuechter & Reid Expires 3 October 2024 [Page 26] Internet-Draft DETIM Architecture April 2024 11.2.4. HHIT Status This document requests a new registry for HHIT Status under the DRIP registry group (https://www.iana.org/assignments/drip/drip.xhtml). 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: +=======+============+===============================+===========+ | 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 | This RFC | | | | (but not expired) | | +-------+------------+-------------------------------+-----------+ Table 5 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. Wiethuechter & Reid Expires 3 October 2024 [Page 27] Internet-Draft DETIM Architecture April 2024 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. Wiethuechter & Reid Expires 3 October 2024 [Page 28] Internet-Draft DETIM Architecture April 2024 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 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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, . [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, . [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, . [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, . 15.2. Informative References Wiethuechter & Reid Expires 3 October 2024 [Page 29] Internet-Draft DETIM Architecture April 2024 [cbor-cert] 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, 4 March 2024, . [CTA2063A] "ANSI/CTA 2063-A Small Unmanned Aerial Systems Numbers", September 2019, . [dane-clients] Huque, S. and V. Dukhovni, "TLS Client Authentication via DANE TLSA records", Work in Progress, Internet-Draft, draft-ietf-dance-client-auth-05, 13 January 2024, . [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-49, 21 February 2024, . [drip-dki] Moskowitz, R. and S. W. Card, "The DRIP DET public Key Infrastructure", Work in Progress, Internet-Draft, draft- moskowitz-drip-dki-09, 23 October 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-c2-14, 16 March 2024, . [F3411] ASTM International, "Standard Specification for Remote ID and Tracking", ASTM F3411-22A, DOI 10.1520/F3411-22A, July 2022, . [FAA-RID-NPRM] "Notice of Proposed Rule Making on Remote Identification of Unmanned Aircraft Systems", December 2019. Wiethuechter & Reid Expires 3 October 2024 [Page 30] Internet-Draft DETIM Architecture April 2024 [RFC1886] Thomson, S. and C. Huitema, "DNS Extensions to support IP version 6", RFC 1886, DOI 10.17487/RFC1886, December 1995, . [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, . [RFC5730] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)", STD 69, RFC 5730, DOI 10.17487/RFC5730, August 2009, . [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, . [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, . [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, . [RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015, . [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, . [RFC8392] Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig, "CBOR Web Token (CWT)", RFC 8392, DOI 10.17487/RFC8392, May 2018, . [RFC9082] Hollenbeck, S. and A. Newton, "Registration Data Access Protocol (RDAP) Query Format", STD 95, RFC 9082, DOI 10.17487/RFC9082, June 2021, . Wiethuechter & Reid Expires 3 October 2024 [Page 31] Internet-Draft DETIM Architecture April 2024 [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, . 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 = 6.xxx(rr_data: 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 Figure 5: Resource Record Wire CDDL HHIT IN ( HHIT TYPE STATUS ABBREV [Endorsement(s)] ) Figure 6: Resource Record Text CDDL Type: 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]. Status: 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. Abbreviation: 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. Endorsements: 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). Wiethuechter & Reid Expires 3 October 2024 [Page 32] Internet-Draft DETIM Architecture April 2024 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. {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 Wiethuechter & Reid Expires 3 October 2024 [Page 33] Internet-Draft DETIM Architecture April 2024 Appendix D. DRIP Endorsements for UAS This appendix is normative. D.1. Self Endorsement ; e-type=0, Self Endorsement $$evidence //= (eddsa25519-hi,) $$endorser //= (hhit,) $$signature = (eddsa25519-sig,) Figure 7: Self Endorsement CDDL Used during registration process as an input. $$evidence contains the HI of the endorser. $$endorser contains the HHIT of the endorser. $$signature contains the EdDSA25519 signature. Wiethuechter & Reid Expires 3 October 2024 [Page 34] Internet-Draft DETIM Architecture April 2024 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 8: Self Endorsement Binary TODO Figure 9: Self Endorsement CBOR D.2. Broadcast Endorsement Wiethuechter & Reid Expires 3 October 2024 [Page 35] Internet-Draft DETIM Architecture April 2024 ; e-type=1, SAM Type=1, Broadcast Endorsement $$evidence //= (hhit, eddsa25519-hi,) $$endorser //= (hhit,) $$signature = (eddsa25519-sig,) Figure 10: Broadcast Endorsement CDDL Defined by [drip-auth] in a binary format to support Authentication over ASTM [F3411] constrained links. Used in the DRIP Link format. A required output of registration to a DIME at any level. $$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. Wiethuechter & Reid Expires 3 October 2024 [Page 36] Internet-Draft DETIM Architecture April 2024 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 11: Broadcast Endorsement Binary TODO Wiethuechter & Reid Expires 3 October 2024 [Page 37] Internet-Draft DETIM Architecture April 2024 Figure 12: Broadcast Endorsement CBOR D.3. Wrapper Endorsement ; e-type=2, SAM Type=2, Wrapper Endorsement $$evidence //= (*4 astm-message,) $$endorser //= (hhit,) $$signature = (eddsa25519-sig,) astm-message = bstr .size(25) Figure 13: Wrapper Endorsement CDDL TODO Figure 14: Wrapper Endorsement CBOR TODO Figure 15: Wrapper Endorsement Binary D.4. Manifest Endorsement ; e-type=3, SAM Type=3, Manifest Endorsement $$evidence //= (3*11 manifest-hash,) $$endorser //= (hhit,) $$signature = (eddsa25519-sig,) manifest-hash = bstr .size(8) Figure 16: Manifest Endorsement CDDL TODO Figure 17: Manifest Endorsement CBOR TODO Figure 18: Manifest Endorsement Binary 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 19: Frame Endorsement CDDL Wiethuechter & Reid Expires 3 October 2024 [Page 38] Internet-Draft DETIM Architecture April 2024 TODO Figure 20: Frame Endorsement CBOR TODO Figure 21: Frame Endorsement Binary Appendix E. DNS Examples This appendix is informative. E.1. Operator @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 DET ( 2001003fff800005ba8af5252a35030e 0 1 "TEST DRIP" "" ... ) e.0.3.0.5.3.a.2.5.2.5.f.a.8.a.b.5.0 IN HIP ( 5 2001003fff800005ba8af5252a35030e ... ) e.0.3.0.5.3.a.2.5.2.5.f.a.8.a.b.5.0 IN URI ( https://example.com/operator/* ) E.2. Session ID @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 DET ( 2001003fff800005b6ce935b616306d4 0 1 "TEST DRIP" "" ... ) 4.d.6.0.3.6.1.6.b.5.3.9.e.c.6.b.5.0 IN HIP ( 5 2001003fff800005b6ce935b616306d4 ... ) 4.d.6.0.3.6.1.6.b.5.3.9.e.c.6.b.5.0 IN URI ( https://example.com/session/* ) E.3. 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 DET ( 2001003fff8000054e486394a60bb669 0 1 "TEST DRIP" "" ... ) 9.6.6.b.b.0.6.a.4.9.3.6.8.4.e.4.5.0 IN HIP ( 5 2001003fff8000054e486394a60bb669 ... ) 9.6.6.b.b.0.6.a.4.9.3.6.8.4.e.4.5.0 IN URI ( https://example.com/dime/* ) Wiethuechter & Reid Expires 3 October 2024 [Page 39] Internet-Draft DETIM Architecture April 2024 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 3 October 2024 [Page 40]