rfc9434.original   rfc9434.txt 
drip S. Card Internet Engineering Task Force (IETF) S. Card
Internet-Draft A. Wiethuechter Request for Comments: 9434 A. Wiethuechter
Intended status: Informational AX Enterprize Category: Informational AX Enterprize
Expires: 6 September 2023 R. Moskowitz ISSN: 2070-1721 R. Moskowitz
HTT Consulting HTT Consulting
S. Zhao (Editor) S. Zhao, Ed.
Intel Intel
A. Gurtov A. Gurtov
Linköping University Linköping University
5 March 2023 July 2023
Drone Remote Identification Protocol (DRIP) Architecture Drone Remote Identification Protocol (DRIP) Architecture
draft-ietf-drip-arch-31
Abstract Abstract
This document describes an architecture for protocols and services to This document describes an architecture for protocols and services to
support Unmanned Aircraft System (UAS) Remote Identification (RID) support Unmanned Aircraft System Remote Identification and tracking
and tracking, plus UAS RID-related communications. This architecture (UAS RID), plus UAS-RID-related communications. This architecture
adheres to the requirements listed in the DRIP Requirements document adheres to the requirements listed in the Drone Remote Identification
(RFC 9153). Protocol (DRIP) Requirements document (RFC 9153).
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This document is not an Internet Standards Track specification; it is
provisions of BCP 78 and BCP 79. published for informational purposes.
Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
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approved by the IESG are candidates for any level of Internet
Standard; see Section 2 of RFC 7841.
This Internet-Draft will expire on 6 September 2023. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9434.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction
1.1. Overview of UAS RID and its Standardization . . . . . . . 3 1.1. Overview of UAS RID and Its Standardization
1.2. Overview of Types of UAS Remote ID . . . . . . . . . . . 4 1.2. Overview of Types of UAS Remote ID
1.2.1. Broadcast RID . . . . . . . . . . . . . . . . . . . . 5 1.2.1. Broadcast RID
1.2.2. Network RID . . . . . . . . . . . . . . . . . . . . . 5 1.2.2. Network RID
1.3. Overview of USS Interoperability . . . . . . . . . . . . 7 1.3. Overview of USS Interoperability
1.4. Overview of DRIP Architecture . . . . . . . . . . . . . . 8 1.4. Overview of DRIP Architecture
2. Terms and Definitions . . . . . . . . . . . . . . . . . . . . 10 2. Terms and Definitions
2.1. Additional Abbreviations . . . . . . . . . . . . . . . . 11 2.1. Additional Abbreviations
2.2. Additional Definitions . . . . . . . . . . . . . . . . . 11 2.2. Additional Definitions
3. HHIT as the DRIP Entity Identifier . . . . . . . . . . . . . 12 3. HHIT as the DRIP Entity Identifier
3.1. UAS Remote Identifiers Problem Space . . . . . . . . . . 12 3.1. UAS Remote Identifiers Problem Space
3.2. HHIT as a Cryptographic Identifier . . . . . . . . . . . 13 3.2. HHIT as a Cryptographic Identifier
3.3. HHIT as A Trustworthy DRIP Entity Identifier . . . . . . 13 3.3. HHIT as a Trustworthy DRIP Entity Identifier
3.4. HHIT for DRIP Identifier Registration and Lookup . . . . 15 3.4. HHIT for DRIP Identifier Registration and Lookup
4. DRIP Identifier Registration and Registries . . . . . . . . . 15 4. DRIP Identifier Registration and Registries
4.1. Public Information Registry . . . . . . . . . . . . . . . 15 4.1. Public Information Registry
4.1.1. Background . . . . . . . . . . . . . . . . . . . . . 16 4.1.1. Background
4.1.2. Public DRIP Identifier Registry . . . . . . . . . . . 16 4.1.2. Public DRIP Identifier Registry
4.2. Private Information Registry . . . . . . . . . . . . . . 16 4.2. Private Information Registry
4.2.1. Background . . . . . . . . . . . . . . . . . . . . . 16 4.2.1. Background
4.2.2. Information Elements . . . . . . . . . . . . . . . . 17 4.2.2. Information Elements
4.2.3. Private DRIP Identifier Registry Methods . . . . . . 17 4.2.3. Private DRIP Identifier Registry Methods
4.2.4. Alternative Private DRIP Registry Methods . . . . . . 17 4.2.4. Alternative Private DRIP Registry Methods
5. DRIP Identifier Trust . . . . . . . . . . . . . . . . . . . . 17 5. DRIP Identifier Trust
6. Harvesting Broadcast Remote ID messages for UTM Inclusion . . 18 6. Harvesting Broadcast Remote ID Messages for UTM Inclusion
6.1. The CS-RID Finder . . . . . . . . . . . . . . . . . . . . 19 6.1. The CS-RID Finder
6.2. The CS-RID SDSP . . . . . . . . . . . . . . . . . . . . . 19 6.2. The CS-RID SDSP
7. DRIP Contact . . . . . . . . . . . . . . . . . . . . . . . . 20 7. DRIP Contact
8. Security Considerations . . . . . . . . . . . . . . . . . . . 21 8. IANA Considerations
8.1. Private Key Physical Security . . . . . . . . . . . . . . 21 9. Security Considerations
8.2. Quantum Resistant Cryptography . . . . . . . . . . . . . 21 9.1. Private Key Physical Security
8.3. Denial Of Service (DoS) Protection . . . . . . . . . . . 22 9.2. Quantum Resistant Cryptography
8.4. Spoofing & Replay Protection . . . . . . . . . . . . . . 22 9.3. Denial of Service (DoS) Protection
8.5. Timestamps & Time Sources . . . . . . . . . . . . . . . . 22 9.4. Spoofing & Replay Protection
9. Privacy & Transparency Considerations . . . . . . . . . . . . 23 9.5. Timestamps & Time Sources
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 10. Privacy & Transparency Considerations
10.1. Normative References . . . . . . . . . . . . . . . . . . 23 11. References
10.2. Informative References . . . . . . . . . . . . . . . . . 24 11.1. Normative References
11.2. Informative References
Appendix A. Overview of Unmanned Aircraft Systems (UAS) Traffic Appendix A. Overview of UAS Traffic Management (UTM)
Management (UTM) . . . . . . . . . . . . . . . . . . . . 28 A.1. Operation Concept
A.1. Operation Concept . . . . . . . . . . . . . . . . . . . . 28 A.2. UAS Service Supplier (USS)
A.2. UAS Service Supplier (USS) . . . . . . . . . . . . . . . 29 A.3. UTM Use Cases for UAS Operations
A.3. UTM Use Cases for UAS Operations . . . . . . . . . . . . 29 Appendix B. Automatic Dependent Surveillance Broadcast (ADS-B)
Appendix B. Automatic Dependent Surveillance Broadcast Acknowledgments
(ADS-B) . . . . . . . . . . . . . . . . . . . . . . . . . 30 Authors' Addresses
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31
1. Introduction 1. Introduction
This document describes an architecture for protocols and services to This document describes an architecture for protocols and services to
support Unmanned Aircraft System (UAS) Remote Identification (RID) support Unmanned Aircraft System Remote Identification and tracking
and tracking, plus RID-related communications. The architecture (UAS RID), plus UAS-RID-related communications. The architecture
takes into account both current (including proposed) regulations and takes into account both current (including proposed) regulations and
non-IETF technical standards. non-IETF technical standards.
The architecture adheres to the requirements listed in the DRIP The architecture adheres to the requirements listed in the DRIP
Requirements document [RFC9153] and illustrates how all of them can Requirements document [RFC9153] and illustrates how all of them can
be met, except for GEN-7 QoS, which is left for future work. The be met, except for GEN-7 QoS, which is left for future work. The
requirements document provides an extended introduction to the requirements document provides an extended introduction to the
problem space and use cases. Further, this architecture document problem space and use cases. Further, this architecture document
frames the DRIP Entity Tag (DET) [I-D.ietf-drip-rid] within the frames the DRIP Entity Tag (DET) [RFC9374] within the architecture.
architecture.
1.1. Overview of UAS RID and its Standardization 1.1. Overview of UAS RID and Its Standardization
UAS RID is an application that enables UAS to be identified by UAS UAS RID is an application that enables UAS to be identified by UAS
Traffic Management (UTM) and UAS Service Suppliers (USS) (Appendix A) Traffic Management (UTM), UAS Service Suppliers (USS) (Appendix A),
and third party entities such as law enforcement. Many and third-party entities, such as law enforcement. Many
considerations (e.g., safety and security) dictate that UAS be considerations (e.g., safety and security) dictate that UAS be
remotely identifiable. remotely identifiable.
Civil Aviation Authorities (CAAs) worldwide are mandating UAS RID. Civil Aviation Authorities (CAAs) worldwide are mandating UAS RID.
CAAs currently promulgate performance-based regulations that do not CAAs currently promulgate performance-based regulations that do not
specify techniques, but rather cite industry consensus technical specify techniques but rather cite industry consensus technical
standards as acceptable means of compliance. standards as acceptable means of compliance.
USA Federal Aviation Administration (FAA) USA Federal Aviation Administration (FAA)
The FAA published a Notice of Proposed Rule Making [NPRM] in 2019 The FAA published a Notice of Proposed Rule Making [NPRM] in 2019
and thereafter published a "Final Rule" in 2021 [FAA_RID], and thereafter published a "Final Rule" in 2021 [FAA_RID],
imposing requirements on UAS manufacturers and operators, both imposing requirements on UAS manufacturers and operators, both
commercial and recreational. The rule states that Automatic commercial and recreational. The rule states that Automatic
Dependent Surveillance Broadcast (ADS-B) Out and transponders Dependent Surveillance Broadcast (ADS-B) Out and transponders
cannot be used to satisfy the UAS RID requirements on UAS to which cannot be used to satisfy the UAS RID requirements on UAS to which
the rule applies (see Appendix B). the rule applies (see Appendix B).
European Union Aviation Safety Agency (EASA) European Union Aviation Safety Agency (EASA)
In pursuit of the "U-space" concept of a single European airspace In pursuit of the "U-space" concept of a single European airspace
safely shared by manned and unmanned aircraft, the EASA published safely shared by manned and unmanned aircraft, the EASA published
a [Delegated] regulation in 2019 imposing requirements on UAS a [Delegated] regulation in 2019, imposing requirements on UAS
manufacturers and third-country operators, including but not manufacturers and third-country operators, including but not
limited to UAS RID requirements. The same year, EASA also limited to UAS RID requirements. The same year, the EASA also
published an [Implementing] regulation laying down detailed rules published a regulation [Implementing], laying down detailed rules
and procedures for UAS operations and operating personnel, which and procedures for UAS operations and operating personnel, which
then was updated in 2021 [Implementing_update]. A Notice of then was updated in 2021 [Implementing_update]. A Notice of
Proposed Amendment [NPA] was published in 2021 to provide more Proposed Amendment [NPA] was published in 2021 to provide more
information about the development of acceptable means of information about the development of acceptable means of
compliance and guidance material to support U-space regulations. compliance and guidance material to support U-space regulations.
American Society for Testing and Materials (ASTM) American Society for Testing and Materials (ASTM)
ASTM International, Technical Committee F38 (UAS), Subcommittee ASTM International, Technical Committee F38 (UAS), Subcommittee
F38.02 (Aircraft Operations), Work Item WK65041, developed the F38.02 (Aircraft Operations), Work Item WK65041 developed an ASTM
ASTM [F3411-22a] Standard Specification for Remote ID and standard [F3411-22a], titled "Standard Specification for Remote ID
Tracking. and Tracking".
ASTM defines one set of UAS RID information and two means, MAC-
layer broadcast and IP-layer network, of communicating it. If an
UAS uses both communication methods, the same information must be
provided via both means. [F3411-22a] is the technical standard
basis of the [F3586-22] "Means Of Compliance" (MOC) accepted by
the FAA as per [MOC-NOA] to the FAA's UAS RID final rule [FAA_RID]
and is expected to be accepted by some other CAAs.
The 3rd Generation Partnership Project (3GPP) ASTM defines one set of UAS RID information and two means, Media
Access Control (MAC) layer broadcast and IP layer network, of
communicating it. If a UAS uses both communication methods, the
same information must be provided via both means. [F3411-22a] is
the technical standard basis of the Means Of Compliance (MOC)
specified in [F3586-22]. The FAA has accepted [F3586-22] as a MOC
to the FAA's UAS RID Final Rule [FAA_RID], with some caveats, as
per [MOC-NOA]. Other CAAs are expected to accept the same or
other MOCs likewise based on [F3411-22a].
3rd Generation Partnership Project (3GPP)
With Release 16, the 3GPP completed the UAS RID requirement study With Release 16, the 3GPP completed the UAS RID requirement study
[TS-22.825] and proposed a set of use cases in the mobile network [TR-22.825] and proposed a set of use cases in the mobile network
and services that can be offered based on UAS RID. The Release 17 and services that can be offered based on UAS RID. The Release 17
study [TR-23.755] and specification [TS-23.255] focus on enhanced study [TR-23.755] and specification [TS-23.255] focus on enhanced
UAS service requirements and provides the protocol and application UAS service requirements and provide the protocol and application
architecture support that will be applicable for both 4G and 5G architecture support that will be applicable for both 4G and 5G
networks. The study of Further Architecture Enhancement for networks. The study of Further Architecture Enhancement for
Uncrewed Aerial Vehicles (UAV) and Urban Air Mobility (UAM) Uncrewed Aerial Vehicles (UAV) and Urban Air Mobility (UAM) in
[FS_AEUA] in Release 18 further enhances the communication Release 18 [FS_AEUA] further enhances the communication mechanism
mechanism between UAS and USS/UTM. The DRIP Entity Tag in between UAS and USS/UTM. The DET in Section 3 may be used as the
Section 3 may be used as the 3GPP CAA-level UAS ID for Remote 3GPP CAA-level UAS ID for RID purposes.
Identification purposes.
1.2. Overview of Types of UAS Remote ID 1.2. Overview of Types of UAS Remote ID
This specification introduces two types of UAS Remote ID defined in This specification introduces two types of UAS Remote IDs as defined
ASTM [F3411-22a]. in ASTM [F3411-22a].
1.2.1. Broadcast RID 1.2.1. Broadcast RID
[F3411-22a] defines a set of UAS RID messages for direct, one-way, [F3411-22a] defines a set of UAS RID messages for direct, one-way
broadcast transmissions from the UA over Bluetooth or Wi-Fi. These broadcast transmissions from the Unmanned Aircraft (UA) over
are currently defined as MAC-Layer messages. Internet (or other Wide Bluetooth or Wi-Fi. These are currently defined as MAC layer
Area Network) connectivity is only needed for UAS registry messages. Internet (or other Wide Area Network) connectivity is only
information lookup by Observers using the directly received UAS ID. needed for UAS registry information lookup by Observers using the
Broadcast RID should be functionally usable in situations with no directly received UAS ID. Broadcast RID should be functionally
Internet connectivity. usable in situations with no Internet connectivity.
The minimum Broadcast RID data flow is illustrated in Figure 1. The minimum Broadcast RID data flow is illustrated in Figure 1.
+------------------------+ +------------------------+
| Unmanned Aircraft (UA) | | Unmanned Aircraft (UA) |
+-----------o------------+ +-----------o------------+
| |
| app messages directly over | app messages directly over
| one-way RF data link (no IP) | one-way RF data link (no IP)
| |
v v
+------------------o-------------------+ +------------------o-------------------+
| Observer's device (e.g., smartphone) | | Observer's device (e.g., smartphone) |
+--------------------------------------+ +--------------------------------------+
Figure 1 Figure 1: Minimum Broadcast RID Data Flow
Broadcast RID provides information only about unmanned aircraft (UA) Broadcast RID provides information only about UA within direct Radio
within direct Radio Frequency (RF) Line-Of-Sight (LOS), typically Frequency (RF) Line Of Sight (LOS), typically similar to Visual LOS
similar to Visual LOS (VLOS), with a range up to approximately 1 km. (VLOS), with a range up to approximately 1 km. This information may
This information may be 'harvested' from received broadcasts and made be 'harvested' from received broadcasts and made available via the
available via the Internet, enabling surveillance of areas too large Internet, enabling surveillance of areas too large for local direct
for local direct visual observation or direct RF link-based ID (see visual observation or direct RF link-based identification (see
Section 6). Section 6).
1.2.2. Network RID 1.2.2. Network RID
[F3411-22a], using the same data dictionary that is the basis of [F3411-22a], using the same data dictionary that is the basis of
Broadcast RID messages, defines a Network Remote Identification (Net- Broadcast RID messages, defines a Network Remote Identification (Net-
RID) data flow as follows. RID) data flow as follows.
* The information to be reported via UAS RID is generated by the * The information to be reported via UAS RID is generated by the
UAS. Typically some of this data is generated by the UA and some UAS. Typically, some of this data is generated by the UA and some
by the GCS (Ground Control Station), e.g., their respective Global by the Ground Control Station (GCS), e.g., their respective
Navigation Satellite System (GNSS) derived locations. locations derived from the Global Navigation Satellite System
(GNSS).
* The information is sent by the UAS (UA or GCS) via unspecified * The information is sent by the UAS (UA or GCS) via unspecified
means to the cognizant Network Remote Identification Service means to the cognizant Network Remote Identification Service
Provider (Net-RID SP), typically the USS under which the UAS is Provider (Net-RID SP), typically the USS under which the UAS is
operating if participating in UTM. operating if it is participating in UTM.
* The Net-RID SP publishes via the Discovery and Synchronization * The Net-RID SP publishes, via the Discovery and Synchronization
Service (DSS) over the Internet that it has operations in various Service (DSS) over the Internet, that it has operations in various
4-D airspace volumes (Section 2.2 of [RFC9153]), describing the 4-D airspace volumes (Section 2.2 of [RFC9153]), describing the
volumes but not the operations. volumes but not the operations.
* An Observer's device, which is expected, but not specified, to be * An Observer's device, which is expected but not specified to be
web-based, queries a Network Remote Identification Display based on the Web, queries a Network Remote Identification Display
Provider (Net-RID DP), typically also a USS, about any operations Provider (Net-RID DP), typically also a USS, about any operations
in a specific 4-D airspace volume. in a specific 4-D airspace volume.
* Using fully specified web-based methods over the Internet, the * Using fully specified Web-based methods over the Internet, the
Net-RID DP queries all Net-RID SPs that have operations in volumes Net-RID DP queries all Net-RID SPs that have operations in volumes
intersecting that of the Observer's query for details on all such intersecting that of the Observer's query for details on all such
operations. operations.
* The Net-RID DP aggregates information received from all such Net- * The Net-RID DP aggregates information received from all such Net-
RID SPs and responds to the Observer's query. RID SPs and responds to the Observer's query.
The minimum Net-RID data flow is illustrated in Figure 2: The minimum Net-RID data flow is illustrated in Figure 2:
+-------------+ ****************** +-------------+ ******************
skipping to change at page 6, line 52 skipping to change at line 281
| | * '------*-----o | | | * '------*-----o |
| | * * | Net-RID DP | | | * * | Net-RID DP |
| | * .------*-----o | | | * .------*-----o |
| | * | * +------------+ | | * | * +------------+
| | * | * | | * | *
| | * | * +------------+ | | * | * +------------+
+--o-------o--+ * '------*-----o Observer's | +--o-------o--+ * '------*-----o Observer's |
| GCS | * * | Device | | GCS | * * | Device |
+-------------+ ****************** +------------+ +-------------+ ****************** +------------+
Figure 2 Figure 2: Minimum Net-RID Data Flow
Command and Control (C2) must flow from the GCS to the UA via some Command and Control (C2) must flow from the GCS to the UA via some
path. Currently (in the year 2022) this is typically a direct RF path. Currently (in the year 2023), this is typically a direct RF
link; however, with increasing Beyond Visual Line of Sight (BVLOS) link; however, with increasing Beyond Visual Line Of Sight (BVLOS)
operations, it is expected often to be a wireless link at either end operations, it is expected to often be a wireless link at either end
with the Internet between. with the Internet between.
Telemetry (at least the UA's position and heading) flows from the UA Telemetry (at least the UA's position and heading) flows from the UA
to the GCS via some path, typically the reverse of the C2 path. to the GCS via some path, typically the reverse of the C2 path.
Thus, UAS RID information pertaining to both the GCS and the UA can Thus, UAS RID information pertaining to both the GCS and the UA can
be sent, by whichever has Internet connectivity, to the Net-RID SP, be sent by whichever has Internet connectivity to the Net-RID SP,
typically the USS managing the UAS operation. typically the USS managing the UAS operation.
The Net-RID SP forwards UAS RID information via the Internet to The Net-RID SP forwards UAS RID information via the Internet to
subscribed Net-RID DPs, typically USS. Subscribed Net-RID DPs then subscribed Net-RID DPs, typically the USS. Subscribed Net-RID DPs
forward RID information via the Internet to subscribed Observer then forward RID information via the Internet to subscribed Observer
devices. Regulations require and [F3411-22a] describes UAS RID data devices. Regulations require and [F3411-22a] describes UAS RID data
elements that must be transported end-to-end from the UAS to the elements that must be transported end to end from the UAS to the
subscribed Observer devices. subscribed Observer devices.
[F3411-22a] prescribes the protocols between the Net-RID SP, Net-RID [F3411-22a] prescribes the protocols between the Net-RID SP, Net-RID
DP, and the DSS. It also prescribes data elements (in JSON) between DP, and DSS. It also prescribes data elements (in JSON) between the
the Observer and the Net-RID DP. DRIP could address standardization Observer and the Net-RID DP. DRIP could address standardization of
of secure protocols between the UA and GCS (over direct wireless and secure protocols between the UA and the GCS (over direct wireless and
Internet connection), between the UAS and the Net-RID SP, and/or Internet connection), between the UAS and the Net-RID SP, and/or
between the Net-RID DP and Observer devices. between the Net-RID DP and Observer devices.
Informative note: Neither link layer protocols nor the use of _Neither link-layer protocols nor the use of links (e.g., the link
links (e.g., the link often existing between the GCS and the often existing between the GCS and the UA) for any purpose other than
UA) for any purpose other than carriage of UAS RID information carriage of UAS RID information are in the scope of Network RID
is in the scope of [F3411-22a] Network RID. [F3411-22a]._
1.3. Overview of USS Interoperability 1.3. Overview of USS Interoperability
With Net-RID, there is direct communication between each UAS and its With Net-RID, there is direct communication between each UAS and its
USS. Multiple USS exchange information with the assistance of a DSS USS. Multiple USS exchange information with the assistance of a DSS
so all USS collectively have knowledge about all activities in a 4D so all USS collectively have knowledge about all activities in a 4-D
airspace. The interactions among an Observer, multiple UAS, and airspace. The interactions among an Observer, multiple UAS, and
their USS are shown in Figure 3. their USS are shown in Figure 3.
+------+ +----------+ +------+ +------+ +----------+ +------+
| UAS1 | | Observer | | UAS2 | | UAS1 | | Observer | | UAS2 |
+---o--+ +-----o----+ +--o---+ +---o--+ +-----o----+ +--o---+
| | | | | |
******|*************|************|****** ******|*************|************|******
* | | | * * | | | *
* | +---o--+ | * * | +---o--+ | *
skipping to change at page 8, line 24 skipping to change at line 341
* | | | | | * * | | | | | *
* +-o--o-+ +--o--+ +-o--o-+ * * +-o--o-+ +--o--+ +-o--o-+ *
* | o----o DSS o-----o | * * | o----o DSS o-----o | *
* | USS1 | +-----+ | USS2 | * * | USS1 | +-----+ | USS2 | *
* | o----------------o | * * | o----------------o | *
* +------+ +------+ * * +------+ +------+ *
* * * *
* Internet * * Internet *
**************************************** ****************************************
Figure 3 Figure 3: Interactions Between Observers, UAS, and USS
1.4. Overview of DRIP Architecture 1.4. Overview of DRIP Architecture
Figure 4 illustrates a global UAS RID usage scenario. Broadcast RID Figure 4 illustrates a global UAS RID usage scenario. Broadcast RID
links are not shown as they reach from any UA to any listening links are not shown, as they reach from any UA to any listening
receiver in range and thus would obscure the intent of the figure. receiver in range and thus would obscure the intent of the figure.
Figure 4 shows, as context, some entities and interfaces beyond the Figure 4 shows, as context, some entities and interfaces beyond the
scope of DRIP (as currently (2022) chartered). Multiple UAS are scope of DRIP (as currently (2023) chartered). Multiple UAS are
shown, each with its own UA controlled by its own GCS, potentially shown, each with its own UA controlled by its own GCS, potentially
using the same or different USS, with the UA potentially using the same or different USS, with the UA potentially
communicating directly with each other (V2V) especially for low communicating directly with each other (V2V), especially for low-
latency safety related purposes (DAA). latency, safety-related purposes (DAA).
*************** *************** *************** ***************
* UAS1 * * UAS2 * * UAS1 * * UAS2 *
* * * * * * * *
* +--------+ * DAA/V2V * +--------+ * * +--------+ * DAA/V2V * +--------+ *
* | UA o--*----------------------------------------*--o UA | * * | UA o--*----------------------------------------*--o UA | *
* +--o--o--+ * * +--o--o--+ * * +--o--o--+ * * +--o--o--+ *
* | | * +------+ Lookups +------+ * | | * * | | * +------+ Lookups +------+ * | | *
* | | * | GPOD o------. .------o PSOD | * | | * * | | * | GPOD o------. .------o PSOD | * | | *
* | | * +------+ | | +------+ * | | * * | | * +------+ | | +------+ * | | *
skipping to change at page 9, line 39 skipping to change at line 389
+--o--+ +--o--+
| DNS | | DNS |
+-----+ +-----+
DAA: Detect And Avoid DAA: Detect And Avoid
GPOD: General Public Observer Device GPOD: General Public Observer Device
PSOD: Public Safety Observer Device PSOD: Public Safety Observer Device
V2I: Vehicle-to-Infrastructure V2I: Vehicle-to-Infrastructure
V2V: Vehicle-to-Vehicle V2V: Vehicle-to-Vehicle
Figure 4 Figure 4: Global UAS RID Usage Scenario
Informative note: see [RFC9153] for detailed definitions. | Informative note: See [RFC9153] for detailed definitions.
DRIP is meant to leverage existing Internet resources (standard DRIP is meant to leverage existing Internet resources (standard
protocols, services, infrastructures, and business models) to meet protocols, services, infrastructures, and business models) to meet
UAS RID and closely related needs. DRIP will specify how to apply UAS RID and closely related needs. DRIP will specify how to apply
IETF standards, complementing [F3411-22a] and other external IETF standards, complementing [F3411-22a] and other external
standards, to satisfy UAS RID requirements. standards, to satisfy UAS RID requirements.
This document outlines the DRIP architecture in the context of the This document outlines the DRIP architecture in the context of the
UAS RID architecture. This includes closing the gaps between the UAS RID architecture. This includes closing the gaps between the
CAAs' Concepts of Operations and [F3411-22a] as it relates to the use CAAs' concepts of operations and [F3411-22a] as it relates to the use
of Internet technologies and UA direct RF communications. Issues of Internet technologies and UA-direct RF communications. Issues
include, but are not limited to: include, but are not limited to:
- Design of trustworthy remote identifiers required by GEN-1 * the design of trustworthy remote identifiers required by GEN-1
(Section 3), especially but not exclusively for use as single- (Section 3), especially but not exclusively for use as single-use
use session IDs. session IDs,
- Mechanisms to leverage the Domain Name System (DNS [RFC1034]), * mechanisms to leverage the Domain Name System (DNS) [RFC1034] for
for registering and publishing public and private information registering and publishing public and private information (see
(see Section 4.1 and Section 4.2) as required by REG-1 and REG- Sections 4.1 and 4.2), as required by REG-1 and REG-2,
2.
- Specific authentication methods and message payload formats to * specific authentication methods and message payload formats to
enable verification that Broadcast RID messages were sent by enable verification that Broadcast RID messages were sent by the
the claimed sender (Section 5) and that the sender is in the claimed sender (Section 5) and that the sender is in the claimed
claimed DIME (Section 4 and Section 5) as required by GEN-2. DRIP Identity Management Entity (DIME) (see Sections 4 and 5), as
required by GEN-2,
- Harvesting Broadcast RID messages for UTM inclusion, with the * harvesting Broadcast RID messages for UTM inclusion, with the
optional DRIP extension of Crowd Sourced Remote ID (CS-RID, optional DRIP extension of Crowdsourced Remote ID (CS-RID)
Section 6), using the DRIP support for gateways required by (Section 6), using the DRIP support for gateways required by GEN-5
GEN-5 [RFC9153]. [RFC9153],
- Methods for instantly establishing secure communications * methods for instantly establishing secure communications between
between an Observer and the pilot of an observed UAS an Observer and the pilot of an observed UAS (Section 7), using
(Section 7), using the DRIP support for dynamic contact the DRIP support for dynamic contact required by GEN-4 [RFC9153],
required by GEN-4 [RFC9153]. and
- Privacy in UAS RID messages (personal data protection) * privacy in UAS RID messages (personal data protection)
(Section 9). (Section 10).
This document should serve as a main point of entry into the set This document should serve as a main point of entry into the set of
of IETF documents addressing the basic DRIP requirements. IETF documents addressing the basic DRIP requirements.
2. Terms and Definitions 2. Terms and Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in
14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
To encourage comprehension necessary for adoption of DRIP by the To encourage comprehension necessary for adoption of DRIP by the
intended user community, the UAS community's norms are respected intended user community, the UAS community's norms are respected
herein. herein.
This document uses terms defined in [RFC9153]. This document uses terms defined in [RFC9153].
Some of the acronyms have plural forms that remain the same as their Some of the acronyms have plural forms that remain the same as their
singular forms, e.g., UAS can expand to Unmanned Aircraft System singular forms, e.g., "UAS" can expand to "Unmanned Aircraft System"
(singular) or Unmanned Aircraft Systems (plural), as appropriate for (singular) or "Unmanned Aircraft Systems" (plural), as appropriate
the context. This usage is consistent with Section 2.2 of [RFC9153]. for the context. This usage is consistent with Section 2.2 of
[RFC9153].
2.1. Additional Abbreviations 2.1. Additional Abbreviations
DET: DRIP Entity Tag DET: DRIP Entity Tag
EdDSA: Edwards-Curve Digital Signature Algorithm EdDSA: Edwards-curve Digital Signature Algorithm
HHIT: Hierarchical HIT HHIT: Hierarchical HIT
HI: Host Identity HI: Host Identity
HIP: Host Identity Protocol HIP: Host Identity Protocol
HIT: Host Identity Tag HIT: Host Identity Tag
2.2. Additional Definitions 2.2. Additional Definitions
This section introduces the terms "Claim", "Evidence", "Endorsement", This section introduces the terms "Claim", "Evidence", "Endorsement",
and "Certificate" as used in DRIP. A DRIP certificate has a and "Certificate", as used in DRIP. A DRIP certificate has a
different context compared with security certificates and Public Key different context compared with security certificates and Public Key
Infrastructure used in X.509. Infrastructure used in X.509.
Claim: Claim:
A claim shares the same definition as a claim in Remote
A claim shares the same definition as a claim in RATS [RFC9334]; ATtestation procedureS (RATS) [RFC9334]; it is a piece of asserted
it is a piece of asserted information, sometimes in the form of a information, sometimes in the form of a name/value pair. It could
name/value pair. It could also been seen as a predicate (e.g., "X also been seen as a predicate (e.g., "X is Y", "X has property Y",
is Y", "X has property Y", and most importantly "X owns Y" or "X and most importantly "X owns Y" or "X is owned by Y").
is owned by Y").
Evidence: Evidence:
Evidence in DRIP borrows the same definition as in RATS [RFC9334],
Evidence in DRIP borrows the same definition as in RATS [RFC9334];
that is, a set of claims. that is, a set of claims.
Endorsement: Endorsement:
An Endorsement is inspired from RATS [RFC9334]; it is a secure An Endorsement is inspired from RATS [RFC9334]; it is a secure
(i.e. signed) statement vouching the integrity and veracity of (i.e., signed) statement vouching the integrity and veracity of
evidence. evidence.
Certificate: Certificate:
A certificate in DRIP is an endorsement, strictly over identity A certificate in DRIP is an endorsement, strictly over identity
information, signed by a third party. This third party should be information, signed by a third party. This third party should be
one with no stake in the endorsement over which it is signing. one with no stake in the endorsement over which it is signing.
DRIP Identity Management Entity (DIME): DRIP Identity Management Entity (DIME):
A DIME is an entity that performs functions similar to a domain
An entity that performs functions similar to a domain registrar/ registrar/registry. A DIME vets Claims and/or Evidence from a
registry. A DIME vets Claims and/or Evidence from a registrant registrant and delivers back Endorsements and/or Certificates in
and delivers back Endorsements and/or Certificates in response. response. It is a high-level entity in the DRIP registration/
It is a high-level entity in the DRIP registration/provisioning provisioning process that can hold the role of HHIT Domain
process that can hold the role of HDA, RAA, or root of trust Authority (HDA), Registered Assigning Authority (RAA), or root of
(typically the HHIT prefix owner or DNS apex owner) for DETs. trust (typically the HHIT prefix owner or DNS apex owner) for
DETs.
3. HHIT as the DRIP Entity Identifier 3. HHIT as the DRIP Entity Identifier
This section describes the DRIP architectural approach to meeting the This section describes the DRIP architectural approach to meeting the
basic requirements of a DRIP entity identifier within external basic requirements of a DRIP entity identifier within the external
technical standard ASTM [F3411-22a] and regulatory constraints. It technical standard ASTM [F3411-22a] and regulatory constraints. It
justifies and explains the use of Hierarchical Host Identity Tags justifies and explains the use of Hierarchical Host Identity Tags
(HHITs) [I-D.ietf-drip-rid] as self-asserting IPv6 addresses suitable (HHITs) [RFC9374] as self-asserting IPv6 addresses suitable as a UAS
as a UAS ID type and, more generally, as trustworthy multipurpose ID type and, more generally, as trustworthy multipurpose remote
remote identifiers. identifiers.
Self-asserting in this usage means that given the Host Identity (HI), Self-asserting in this usage means that, given the Host Identity
the HHIT ORCHID construction (see section 3.5 of [I-D.ietf-drip-rid]) (HI), the HHIT Overlay Routable Cryptographic Hash IDentifier
and a signature of the DIME on the HHIT and HI; the HHIT can be (ORCHID) construction (see Section 3.5 of [RFC9374]), and a signature
verified by the receiver as a trusted UAS ID. The explicit of the DIME on the HHIT and HI, the HHIT can be verified by the
registration hierarchy within the HHIT provides registration receiver as a trusted UAS ID. The explicit registration hierarchy
discovery (managed by a DRIP Identity Management Entity (DIME)) to within the HHIT provides registration discovery (managed by a DIME)
either yield the HI for a 3rd-party (seeking UAS ID endorsement) to either yield the HI for third-party (seeking UAS ID endorsement)
validation or prove that the HHIT and HI have been registered validation or prove that the HHIT and HI have been registered
uniquely. uniquely.
3.1. UAS Remote Identifiers Problem Space 3.1. UAS Remote Identifiers Problem Space
A DRIP entity identifier needs to be "Trustworthy" (see DRIP A DRIP entity identifier needs to be "Trustworthy" (see DRIP
Requirement GEN-1, ID-4 and ID-5 in [RFC9153]). This means that requirements GEN-1, ID-4, and ID-5 in [RFC9153]). This means that
given a sufficient collection of UAS RID messages, an Observer can given a sufficient collection of UAS RID messages, an Observer can
establish that the identifier claimed therein uniquely belongs to the establish that the identifier claimed therein uniquely belongs to the
claimant. To satisfy DRIP requirements and maintain important claimant. To satisfy DRIP requirements and maintain important
security properties, the DRIP identifier should be self-generated by security properties, the DRIP identifier should be self-generated by
the entity it names (e.g., a UAS) and registered (e.g., with a USS, the entity it names (e.g., a UAS) and registered (e.g., with a USS;
see Requirements GEN-3 and ID-2). see DRIP requirements GEN-3 and ID-2).
However Broadcast RID, especially its support for Bluetooth 4, However, Broadcast RID, especially its support for Bluetooth 4,
imposes severe constraints. A previous revision of the ASTM UAS RID, imposes severe constraints. A previous revision of the ASTM UAS RID,
F3411-19, allowed a UAS ID of types (1, 2, and 3), each of 20 bytes. [F3411-19], allowed a UAS ID of types (1, 2, and 3), each of 20
[F3411-22a] adds type 4, Specific Session ID, for other Standards bytes. [F3411-22a] adds type 4, Specific Session ID, for other
Development Organizations (SDOs) to extend ASTM UAS RID. Type 4 uses Standards Development Organizations (SDOs) to extend ASTM UAS RID.
one byte to index the Specific Session ID subtype, leaving 19 bytes Type 4 uses one byte to index the Specific Session ID subtype,
(see ID-1 of DRIP Requirements [RFC9153]). As described in Section 3 leaving 19 bytes (see ID-1 of DRIP Requirements [RFC9153]). As
of [RFC9153], ASTM has allocated Specific Session ID subtype 1 to described in Section 3 of [RFC9153], ASTM has allocated Specific
IETF DRIP. Session ID subtype 1 to IETF DRIP.
The maximum ASTM UAS RID Authentication Message payload is 201 bytes The maximum ASTM UAS RID Authentication Message payload is 201 bytes
each for Authentication Types 1, 2, 3, and 4. [F3411-22a] adds each for Authentication Types 1, 2, 3, and 4. [F3411-22a] adds
Authentication Type 5 for other SDOs (including the IETF) to extend Authentication Type 5 for other SDOs (including the IETF) to extend
ASTM UAS RID with Specific Authentication Methods (SAM). With type ASTM UAS RID with Specific Authentication Methods (SAMs). With Type
5, one of the 201 bytes is consumed to index the SAM Type, leaving 5, one of the 201 bytes is consumed to index the SAM Type, leaving
only 200 bytes for DRIP authentication payloads, including one or only 200 bytes for DRIP authentication payloads, including one or
more DRIP entity identifiers and associated authentication data. more DRIP entity identifiers and associated authentication data.
3.2. HHIT as a Cryptographic Identifier 3.2. HHIT as a Cryptographic Identifier
The only (known to the authors at the time of this writing) existing The only (known to the authors at the time of writing) existing types
types of IP address compatible identifiers cryptographically derived of IP-address-compatible identifiers cryptographically derived from
from the public keys of the identified entities are Cryptographically the public keys of the identified entities are Cryptographically
Generated Addresses (CGAs) [RFC3972] and Host Identity Tags (HITs) Generated Addresses (CGAs) [RFC3972] and Host Identity Tags (HITs)
[RFC7401]. CGAs and HITs lack registration/retrieval capability. To [RFC7401]. CGAs and HITs lack registration/retrieval capability. To
provide this, each HHIT embeds plaintext information designating the provide this, each HHIT embeds plaintext information designating the
hierarchy within which it is registered and a cryptographic hash of hierarchy within which it is registered, a cryptographic hash of that
that information concatenated with the entity's public key, etc. information concatenated with the entity's public key, etc. Although
Although hash collisions may occur, the DIME can detect them and hash collisions may occur, the DIME can detect them and reject
reject registration requests rather than issue credentials, e.g., by registration requests rather than issue credentials, e.g., by
enforcing a First Come First Served policy. Pre-image hash attacks enforcing a First Come First Served policy [RFC8126]. Preimage hash
are also mitigated through this registration process, locking the attacks are also mitigated through this registration process, locking
HHIT to a specific HI. the HHIT to a specific HI.
3.3. HHIT as A Trustworthy DRIP Entity Identifier 3.3. HHIT as a Trustworthy DRIP Entity Identifier
A Remote UAS ID that can be trustworthy for use in Broadcast RID can A Remote UAS ID that can be trustworthy for use in Broadcast RID can
be built from an asymmetric keypair. In this method, the UAS ID is be built from an asymmetric key pair. In this method, the UAS ID is
cryptographically derived directly from the public key. The proof of cryptographically derived directly from the public key. The proof of
UAS ID ownership (verifiable endorsement, versus mere claim) is UAS ID ownership (verifiable endorsement versus mere claim) is
guaranteed by signing this cryptographic UAS ID with the associated guaranteed by signing this cryptographic UAS ID with the associated
private key. The association between the UAS ID and the private key private key. The association between the UAS ID and the private key
is ensured by cryptographically binding the public key with the UAS is ensured by cryptographically binding the public key with the UAS
ID; more specifically, the UAS ID results from the hash of the public ID; more specifically, the UAS ID results from the hash of the public
key. The public key is designated as the HI while the UAS ID is key. The public key is designated as the HI, while the UAS ID is
designated as the HIT. designated as the HIT.
By construction, the HIT is statistically unique through the By construction, the HIT is statistically unique through the
mandatory use of cryptographic hash functions with second-preimage mandatory use of cryptographic hash functions with second-preimage
resistance. The cryptographically-bound addition of the Hierarchy resistance. The cryptographically bound addition of the hierarchy
and an HHIT registration process provide complete, global HHIT and a HHIT registration process provide complete, global HHIT
uniqueness. This registration forces the attacker to generate the uniqueness. This registration forces the attacker to generate the
same public key rather than a public key that generates the same same public key rather than a public key that generates the same
HHIT. This is in contrast to general IDs (e.g., a UUID or device HHIT. This is in contrast to general IDs (e.g., a Universally Unique
serial number) as the subject in an X.509 certificate. Identifier (UUID) or device serial number) as the subject in an X.509
certificate.
A UA equipped for Broadcast RID MUST be provisioned not only with its A UA equipped for Broadcast RID MUST be provisioned not only with its
HHIT but also with the HI public key from which the HHIT was derived HHIT but also with the HI public key from which the HHIT was derived
and the corresponding private key, to enable message signature. and the corresponding private key to enable message signature.
A UAS equipped for DRIP enhanced Network RID MUST be provisioned A UAS equipped for DRIP-enhanced Network RID MUST be provisioned
likewise; the private key resides only in the ultimate source of likewise; the private key resides only in the ultimate source of
Network RID messages. If the GCS is the source of the Network RID Network RID messages. If the GCS is the source of the Network RID
messages; the GCS MUST hold the private key. If the UA is the source messages, the GCS MUST hold the private key. If the UA is the source
of the Network RID messages and they are being relayed by the GCS; of the Network RID messages and they are being relayed by the GCS,
the UA MUST hold the private key, just as a UA that directly connects the UA MUST hold the private key, just as a UA that directly connects
to the network rather than through its GCS. to the network rather than through its GCS.
Each Observer device functioning with Internet connectivity MAY be Each Observer device functioning with Internet connectivity MAY be
provisioned either with public keys of the DRIP identifier root provisioned either with public keys of the DRIP identifier root
registries or certificates for subordinate registries; each Observer registries or certificates for subordinate registries; each Observer
device that needs to operate without Internet connectivity at any device that needs to operate without Internet connectivity at any
time MUST be so provisioned. time MUST be so provisioned.
HHITs can also be used throughout the USS/UTM system. Operators and HHITs can also be used throughout the USS/UTM system. Operators and
Private Information Registries, as well as other UTM entities, can Private Information Registries, as well as other UTM entities, can
use HHITs for their IDs. Such HHITs can facilitate DRIP security use HHITs for their IDs. Such HHITs can facilitate DRIP security
functions such as used with HIP to strongly mutually authenticate and functions, such as those used with HIP, to strongly mutually
encrypt communications. authenticate and encrypt communications.
A self-endorsement of a HHIT used as a UAS ID can be done in as A self-endorsement of a HHIT used as a UAS ID can be done in as
little as 88-bytes when Ed25519 [RFC8032] is used by only including little as 88 bytes when Ed25519 [RFC8032] is used by only including
the 16-byte HHIT, two 4-byte timestamps, and the 64-byte Ed25519 the 16-byte HHIT, two 4-byte timestamps, and the 64-byte Ed25519
signature. signature.
Ed25519 [RFC8032] is used as the HHIT Mandatory to Implement signing Ed25519 [RFC8032] is used as the HHIT mandatory-to-implement signing
algorithm as [RFC9153] GEN-1 and ID-5 can best be met by restricting algorithm, as GEN-1 and ID-5 [RFC9153] can best be met by restricting
the HI to 32 bytes. A larger public key would rule out the offline the HI to 32 bytes. A larger public key would rule out the offline
endorsement feature that fits within the 200-byte Authentication endorsement feature that fits within the 200-byte Authentication
Message maximum length. Other algorithms that meet this 32 byte Message maximum length. Other algorithms that meet this 32-byte
constraint can be added as deemed needed. constraint can be added as deemed needed.
A DRIP identifier can be assigned to a UAS as a static HHIT by its A DRIP identifier can be assigned to a UAS as a static HHIT by its
manufacturer, such as a single HI and derived HHIT encoded as a manufacturer, such as a single HI and derived HHIT encoded as a
hardware serial number per [CTA2063A]. Such a static HHIT SHOULD hardware serial number, per [CTA2063A]. Such a static HHIT SHOULD
only be used to bind one-time use DRIP identifiers to the unique UA. only be used to bind one-time-use DRIP identifiers to the unique UA.
Depending upon implementation, this may leave a HI private key in the Depending upon implementation, this may leave a HI private key in the
possession of the manufacturer (see also Section 8). possession of the manufacturer (see also Section 9).
In general, Internet access may be needed to validate Endorsements or In general, Internet access may be needed to validate Endorsements or
Certificates. This may be obviated in the most common cases (e.g., Certificates. This may be obviated in the most common cases (e.g.,
endorsement of the UAS ID), even in disconnected environments, by endorsement of the UAS ID), even in disconnected environments, by
pre-populating small caches on Observer devices with DIME public keys prepopulating small caches on Observer devices with DIME public keys
and a chain of Endorsements or Certificates (tracing a path through and a chain of Endorsements or Certificates (tracing a path through
the DIME tree). This is assuming all parties on the trust path also the DIME tree). This is assuming all parties on the trust path also
use HHITs for their identities. use HHITs for their identities.
3.4. HHIT for DRIP Identifier Registration and Lookup 3.4. HHIT for DRIP Identifier Registration and Lookup
UAS RID needs a deterministic lookup mechanism that rapidly provides UAS RID needs a deterministic lookup mechanism that rapidly provides
actionable information about the identified UA. Given the size actionable information about the identified UA. Given the size
constraints imposed by the Bluetooth 4 broadcast media, the UAS ID constraints imposed by the Bluetooth 4 broadcast media, the UAS ID
itself needs to be a non-spoofable inquiry input into the lookup. itself needs to be a non-spoofable inquiry input into the lookup.
A DRIP registration process based on the explicit hierarchy within a A DRIP registration process based on the explicit hierarchy within a
HHIT provides manageable uniqueness of the HI for the HHIT. The HHIT provides manageable uniqueness of the HI for the HHIT. The
hierarchy is defined in [I-D.ietf-drip-rid] and consists of 2-levels, hierarchy is defined in [RFC9374] and consists of 2 levels: an RAA
a Registered Assigning Authority (RAA) and then a Hierarchical HIT and then an HDA. The registration within this hierarchy is the
Domain Authority (HDA). The registration within this hierarchy is defense against a cryptographic hash second-preimage attack on the
the defense against a cryptographic hash second pre-image attack on HHIT (e.g., multiple HIs yielding the same HHIT; see Requirement ID-3
the HHIT (e.g., multiple HIs yielding the same HHIT, see Requirement in [RFC9153]). The First Come First Served registration policy is
ID-3 in [RFC9153]). The First Come First Served registration policy adequate.
is adequate.
A lookup of the HHIT into the DIME provides the registered HI for A lookup of the HHIT into the DIME provides the registered HI for
HHIT proof of ownership and deterministic access to any other needed HHIT proof of ownership and deterministic access to any other needed
actionable information based on inquiry access authority (more actionable information based on inquiry access authority (more
details in Section 4.2). details in Section 4.2).
4. DRIP Identifier Registration and Registries 4. DRIP Identifier Registration and Registries
DRIP registries hold both public and private UAS information (see DRIP registries hold both public and private UAS information (see
PRIV-1 in [RFC9153]) resulting from the DRIP identifier registration PRIV-1 in [RFC9153]) resulting from the DRIP identifier registration
process. Given these different uses, and to improve scalability, process. Given these different uses, and to improve scalability,
security, and simplicity of administration, the public and private security, and simplicity of administration, the public and private
information can be stored in different registries. This section information can be stored in different registries. This section
introduces the public and private information registries for DRIP introduces the public and private information registries for DRIP
identifiers. This DRIP Identifier registration process satisfies the identifiers. In this section, for ease of comprehension, the
following DRIP requirements defined in [RFC9153]: GEN-3, GEN-4, ID-2, registry functions are described (using familiar terminology) without
ID-4, ID-6, PRIV-3, PRIV-4, REG-1, REG-2, REG-3 and REG-4. detailing their assignment to specific implementing entities (or
using unfamiliar jargon). Elsewhere in this document, and in
forthcoming documents detailing the DRIP registration processes and
entities, the more specific term "DRIP Identity Management Entity"
(DIME) will be used. This DRIP identifier registration process
satisfies the following DRIP requirements defined in [RFC9153]: GEN-
3, GEN-4, ID-2, ID-4, ID-6, PRIV-3, PRIV-4, REG-1, REG-2, REG-3, and
REG-4.
4.1. Public Information Registry 4.1. Public Information Registry
4.1.1. Background 4.1.1. Background
The public information registry provides trustable information such The public information registry provides trustable information, such
as endorsements of UAS RID ownership and registration with the HDA as endorsements of UAS RID ownership and registration with the HDA.
(Hierarchical HIT Domain Authority). Optionally, pointers to the Optionally, pointers to the registries for the HDA and RAA implicit
registries for the HDA and RAA (Registered Assigning Authority) in the UAS RID can be included (e.g., for HDA and RAA HHIT|HI used in
implicit in the UAS RID can be included (e.g., for HDA and RAA endorsement signing operations). This public information will be
HHIT|HI used in endorsement signing operations). This public principally used by Observers of Broadcast RID messages. Data on UAS
information will be principally used by Observers of Broadcast RID that only use Network RID is available via an Observer's Net-RID DP
messages. Data on UAS that only use Network RID, is available via an that would directly provide all public registry information. The
Observer's Net-RID DP that would directly provide all public registry Net-RID DP is the only source of information for a query on an
information. The Net-RID DP is the only source of information for a airspace volume.
query on an airspace volume.
| Note: In the above paragraph, | signifies concatenation of
| information, e.g., X | Y is the concatenation of X and Y.
4.1.2. Public DRIP Identifier Registry 4.1.2. Public DRIP Identifier Registry
A DRIP identifier MUST be registered as an Internet domain name (at A DRIP identifier MUST be registered as an Internet domain name (at
an arbitrary level in the hierarchy, e.g., in .ip6.arpa). Thus DNS an arbitrary level in the hierarchy, e.g., in .ip6.arpa). Thus, the
can provide all the needed public DRIP information. A standardized DNS can provide all the needed public DRIP information. A
HHIT FQDN (Fully Qualified Domain Name) can deliver the HI via a HIP standardized HHIT Fully Qualified Domain Name (FQDN) can deliver the
RR (Resource Record) [RFC8005] and other public information (e.g., HI via a HIP Resource Record (RR) [RFC8005] and other public
RAA and HDA PTRs, and HIP RVS (Rendezvous Servers) [RFC8004]). These information (e.g., RAA and HDA PTRs and HIP Rendezvous Servers (RVSs)
public information registries can use DNSSEC to deliver public [RFC8004]). These public information registries can use DNSSEC to
information that is not inherently trustable (e.g., everything other deliver public information that is not inherently trustable (e.g.,
than endorsements). everything other than endorsements).
This DNS entry for the HHIT can also provide a revocation service. This DNS entry for the HHIT can also provide a revocation service.
For example, instead of returning the HI RR it may return some record For example, instead of returning the HI RR, it may return some
showing that the HI (and thus HHIT) has been revoked. record showing that the HI (and thus HHIT) has been revoked.
4.2. Private Information Registry 4.2. Private Information Registry
4.2.1. Background 4.2.1. Background
The private information required for DRIP identifiers is similar to The private information required for DRIP identifiers is similar to
that required for Internet domain name registration. A DRIP that required for Internet domain name registration. A DRIP
identifier solution can leverage existing Internet resources: identifier solution can leverage existing Internet resources, i.e.,
registration protocols, infrastructure, and business models, by registration protocols, infrastructure, and business models, by
fitting into a UAS ID structure compatible with DNS names. The HHIT fitting into a UAS ID structure compatible with DNS names. The HHIT
hierarchy can provide the needed scalability and management hierarchy can provide the needed scalability and management
structure. It is expected that the private information registry structure. It is expected that the private information registry
function will be provided by the same organizations that run a USS, function will be provided by the same organizations that run a USS
and likely integrated with a USS. The lookup function may be and likely integrated with a USS. The lookup function may be
implemented by the Net-RID DPs. implemented by the Net-RID DPs.
4.2.2. Information Elements 4.2.2. Information Elements
When a DET is used as a UA's Session ID, the corresponding When a DET is used as a UA's Session ID, the corresponding
manufacturer assigned serial number MUST be stored in a Private manufacturer-assigned serial number MUST be stored in a private
Information Registry that can be identified uniquely from the DET. information registry that can be identified uniquely from the DET.
When a DET is used as either as UA's Session ID or as a UA's When a DET is used as either a UA's Session ID or a UA's
manufacturer assigned serial number, and the operation is being flown manufacturer-assigned serial number, and the operation is being flown
under UTM, the corresponding UTM system assigned Operational Intent under UTM, the corresponding UTM-system-assigned Operational Intent
Identifier SHOULD be so stored. Other information MAY be so stored, Identifier SHOULD be so stored. Other information MAY be stored as
and often must to satisfy CAA regulations or USS operator policies. such, and often must, to satisfy CAA regulations or USS operator
policies.
4.2.3. Private DRIP Identifier Registry Methods 4.2.3. Private DRIP Identifier Registry Methods
A DRIP private information registry supports essential registry A DRIP private information registry supports essential registry
operations (e.g., add, delete, update, query) using interoperable operations (e.g., add, delete, update, and query) using interoperable
open standard protocols. It can accomplish this by leveraging open standard protocols. It can accomplish this by leveraging
aspects of Extensible Provisioning Protocol (EPP [RFC5730]) and the aspects of the Extensible Provisioning Protocol (EPP) [RFC5730] and
Registry Data Access Protocol (RDAP [RFC7480] [RFC9082] [RFC9083]). the Registry Data Access Protocol (RDAP) [RFC7480] [RFC9082]
The DRIP private information registry in which a given UAS is [RFC9083]. The DRIP private information registry in which a given
registered needs to be findable, starting from the UAS ID, using the UAS is registered needs to be findable, starting from the UAS ID,
methods specified in [RFC9224]. using the methods specified in [RFC9224].
4.2.4. Alternative Private DRIP Registry Methods 4.2.4. Alternative Private DRIP Registry Methods
A DRIP private information registry might be an access-controlled DNS A DRIP private information registry might be an access-controlled DNS
(e.g., via DNS over TLS). Additionally, WebFinger [RFC7033] can be (e.g., via DNS over TLS). Additionally, WebFinger [RFC7033] can be
supported. These alternative methods may be used by Net-RID DP with supported. These alternative methods may be used by a Net-RID DP
specific customers. with specific customers.
5. DRIP Identifier Trust 5. DRIP Identifier Trust
While the DRIP entity identifier is self-asserting, it alone does not While the DRIP entity identifier is self-asserting, it alone does not
provide the trustworthiness (non-repudiation, protection vs spoofing, provide the trustworthiness (i.e., non-repudiation, protection vs.
message integrity protection, scalability, etc.) essential to UAS spoofing, message integrity protection, scalability, etc.) essential
RID, as justified in [RFC9153]. For that it MUST be registered to UAS RID, as justified in [RFC9153]. For that, it MUST be
(under DRIP Registries) and be actively used by the party (in most registered (under DRIP registries) and actively used by the party (in
cases the UA). A sender's identity cannot be proved merely by its most cases the UA). A sender's identity cannot be proved merely by
possessing a DRIP Entity Tag (DET) and broadcasting it as a claim its possessing of a DRIP Entity Tag (DET) and broadcasting it as a
that it belongs to that sender. Sending data signed using that HI's claim that it belongs to that sender. Sending data signed using that
private key proves little, as it is subject to trivial replay attacks HI's private key proves little, as it is subject to trivial replay
using previously broadcast messages. Only sending the DET and a attacks using previously broadcast messages. Only sending the DET
signature on novel (i.e., frequently changing and unpredictable) data and a signature on novel (i.e., frequently changing and
that can be externally validated by the Observer (such as a signed unpredictable) data that can be externally validated by the Observer
Location/Vector message, matching actually seeing the UA at the (such as a signed Location/Vector message that matches actually
location and time reported in the signed message) proves that the seeing the UA at the location and time reported in the signed
observed UA possesses the private key and thus the claimed UAS ID. message) proves that the observed UA possesses the private key and
thus the claimed UAS ID.
The severe constraints of Broadcast RID make it challenging to The severe constraints of Broadcast RID make it challenging to
satisfy UAS RID requirements. From received Broadcast RID messages satisfy UAS RID requirements. From received Broadcast RID messages
and information that can be looked up using the received UAS ID in and information that can be looked up using the received UAS ID in
online registries or local caches, it is possible to establish levels online registries or local caches, it is possible to establish levels
of trust in the asserted information and the Operator. of trust in the asserted information and the operator.
A combination of different DRIP Authentication Messages enables an A combination of different DRIP Authentication Messages enables an
Observer, without Internet connection (offline) or with (online), to Observer, without Internet connection (offline) or with (online), to
validate a UAS DRIP ID in real-time. Some messages must contain the validate a UAS DRIP ID in real time. Some messages must contain the
relevant registration of the UA's DRIP ID in the claimed DIME. Some relevant registration of the UA's DRIP ID in the claimed DIME. Some
messages must contain sender signatures over both static (e.g., messages must contain sender signatures over both static (e.g.,
registration) and dynamically changing (e.g., current UA location) registration) and dynamically changing (e.g., current UA location)
data. Combining these two sets of information, an Observer can piece data. Combining these two sets of information, an Observer can piece
together a chain of trust including real-time evidence to make a together a chain of trust, including real-time evidence to make a
determination on the UA's claims. determination on the UA's claims.
This process (combining the DRIP entity identifier, registries, and This process (combining the DRIP entity identifier, registries, and
authentication formats for Broadcast RID) can satisfy the following authentication formats for Broadcast RID) can satisfy the following
DRIP requirements defined in [RFC9153]: GEN-1, GEN-2, GEN-3, ID-2, DRIP requirements defined in [RFC9153]: GEN-1, GEN-2, GEN-3, ID-2,
ID-3, ID-4, and ID-5. ID-3, ID-4, and ID-5.
6. Harvesting Broadcast Remote ID messages for UTM Inclusion 6. Harvesting Broadcast Remote ID Messages for UTM Inclusion
ASTM anticipated that regulators would require both Broadcast RID and ASTM anticipated that regulators would require both Broadcast RID and
Network RID for large UAS, but allow UAS RID requirements for small Network RID for large UAS but allow UAS RID requirements for small
UAS to be satisfied with the operator's choice of either Broadcast UAS to be satisfied with the operator's choice of either Broadcast
RID or Network RID. The EASA initially specified Broadcast RID for RID or Network RID. The EASA initially specified Broadcast RID for
essentially all UAS, and is now also considering Network RID. The essentially all UAS and is now also considering Network RID. The FAA
FAA UAS RID Final Rules [FAA_RID] permit only Broadcast RID for rule UAS RID Final Rules [FAA_RID] permit only Broadcast RID for rule
compliance, but still encourage Network RID for complementary compliance but still encourage Network RID for complementary
functionality, especially in support of UTM. functionality, especially in support of UTM.
One opportunity is to enhance the architecture with gateways from One opportunity is to enhance the architecture with gateways from
Broadcast RID to Network RID. This provides the best of both and Broadcast RID to Network RID. This provides the best of both and
gives regulators and operators flexibility. It offers advantages gives regulators and operators flexibility. It offers advantages
over either form of UAS RID alone: greater fidelity than Network RID over either form of UAS RID alone, i.e., greater fidelity than
reporting of planned area operations; surveillance of areas too large Network RID reporting of [FAA_RID] planned area operations, together
for local direct visual observation and direct RF-LOS link based with surveillance of areas too large for local direct visual
Broadcast RID (e.g., a city or a national forest). observation and direct Radio Frequency Line Of Sight (RF-LOS) link-
based Broadcast RID (e.g., a city or a national forest).
These gateways could be pre-positioned (e.g., around airports, public These gateways could be pre-positioned (e.g., around airports, public
gatherings, and other sensitive areas) and/or crowd-sourced (as gatherings, and other sensitive areas) and/or crowdsourced (as
nothing more than a smartphone with a suitable app is needed). nothing more than a smartphone with a suitable app is needed).
Crowd-sourcing can be encouraged by quid pro quo, providing CS-RID Crowdsourcing can be encouraged by quid pro quo, providing CS-RID
Surveillance Supplemental Data Service Provider (SDSP) outputs only Surveillance Supplemental Data Service Provider (SDSP) outputs only
to CS-RID Finders. As Broadcast RID media have limited range, to CS-RID Finders. As Broadcast RID media have a limited range,
gateways receiving messages claiming locations far from the gateway messages claiming sender (typically UA) locations far from a physical
can alert authorities or a Surveillance SDSP to the failed sanity layer receiver thereof ("Finder" below, typically Observer device)
check possibly indicating intent to deceive. CS-RID SDSPs can use should arouse suspicion of possible intent to deceive; a fast and
messages with precise date/time/position stamps from the gateways to computationally inexpensive consistency check can be performed (by
multilaterate UA location, independent of the locations claimed in the Finder or the Surveillance SDSP) on application layer data
the messages, which are entirely operator self-reported in UAS RID present in the gateway (claimed UA location vs physical receiver
and UTM, and thus are subject not only to natural time lag and error location), and authorities can be alerted to failed checks. CS-RID
but also operator misconfiguration or intentional deception. SDSPs can use messages with precise date/time/position stamps from
the gateways to multilaterate UA locations, independent of the
locations claimed in the messages, which are entirely self-reported
by the operator in UAS RID and UTM, and thus are subject not only to
natural time lag and error but also operator misconfiguration or
intentional deception.
Multilateration technologies use physical layer information, such as Multilateration technologies use physical layer information, such as
precise Time Of Arrival (TOA) of transmissions from mobile precise Time Of Arrival (TOA) of transmissions from mobile
transmitters at receivers with a priori precisely known locations, to transmitters at receivers with a priori precisely known locations, to
estimate the locations of the mobile transmitters. estimate the locations of the mobile transmitters.
Further, gateways with additional sensors (e.g., smartphones with Further, gateways with additional sensors (e.g., smartphones with
cameras) can provide independent information on the UA type and size, cameras) can provide independent information on the UA type and size,
confirming or refuting those claims made in the UAS RID messages. confirming or refuting those claims made in the UAS RID messages.
Section 6.1 and Section 6.2 define two additional entities that are Sections 6.1 and 6.2 define two additional entities that are required
required to provide this Crowd Sourced Remote ID (CS-RID). to provide this Crowdsourced Remote ID (CS-RID).
This approach satisfies the following DRIP requirements defined in This approach satisfies the following DRIP requirements defined in
[RFC9153]: GEN-5, GEN-11, and REG-1. As Broadcast messages are [RFC9153]: GEN-5, GEN-11, and REG-1. As Broadcast messages are
inherently multicast, GEN-10 is met for local-link multicast to inherently multicast, GEN-10 is met for local-link multicast to
multiple Finders (how multilateration is possible). multiple Finders (this is how multilateration is possible).
6.1. The CS-RID Finder 6.1. The CS-RID Finder
A CS-RID Finder is the gateway for Broadcast Remote ID Messages into A CS-RID Finder is the gateway for Broadcast Remote ID Messages into
UTM. It performs this gateway function via a CS-RID SDSP. A CS-RID UTM. It performs this gateway function via a CS-RID SDSP. A CS-RID
Finder could implement, integrate, or accept outputs from a Broadcast Finder could implement, integrate, or accept outputs from a Broadcast
RID receiver. However, it should not depend upon a direct interface RID receiver. However, it should not depend upon a direct interface
with a GCS, Net-RID SP, Net-RID DP or Net-RID client. It would with a GCS, Net-RID SP, Net-RID DP, or Net-RID client. It would
present a new interface to a CS-RID SDSP, similar to but readily present a new interface to a CS-RID SDSP, similar to but readily
distinguishable from that which a UAS (UA or GCS) presents to a Net- distinguishable from that which a UAS (UA or GCS) presents to a Net-
RID SP. RID SP.
6.2. The CS-RID SDSP 6.2. The CS-RID SDSP
A CS-RID SDSP aggregates and processes (e.g., estimates UA location A CS-RID SDSP aggregates and processes (e.g., estimates UA locations
using multilateration when possible) information collected by CS-RID using multilateration when possible) information collected by CS-RID
Finders. A CS-RID SDSP should present the same interface to a Net- Finders. A CS-RID SDSP should present the same interface to a Net-
RID SP as does a Net-RID DP and to a Net-RID DP as does a Net-RID SP, RID SP as it does to a Net-RID DP and to a Net-RID DP as it does to a
but its data source must be readily distinguishable as via Finders Net-RID SP, but its data source must be readily distinguishable via
rather than direct from the UAS itself. Finders rather than direct from the UAS itself.
7. DRIP Contact 7. DRIP Contact
One of the ways in which DRIP can enhance [F3411-22a] with One of the ways in which DRIP can enhance [F3411-22a] with
immediately actionable information is by enabling an Observer to immediately actionable information is by enabling an Observer to
instantly initiate secure communications with the UAS remote pilot, instantly initiate secure communications with the UAS remote pilot,
Pilot In Command, operator, USS under which the operation is being Pilot In Command, operator, USS under which the operation is being
flown, or other entity potentially able to furnish further flown, or other entity potentially able to furnish further
information regarding the operation and its intent and/or to information regarding the operation and its intent and/or to
immediately influence further conduct or termination of the operation immediately influence further conduct or termination of the operation
(e.g., land or otherwise exit an airspace volume). Such potentially (e.g., land or otherwise exit an airspace volume). Such potentially
distracting communications demand strong "AAA" (Authentication, distracting communications demand strong "AAA" (Authentication,
Attestation, Authorization, Access Control, Accounting, Attribution, Attestation, Authorization, Access Control, Accounting, Attribution,
Audit) per applicable policies (e.g., of the cognizant CAA). Audit), per applicable policies (e.g., of the cognizant CAA).
A DRIP entity identifier based on a HHIT as outlined in Section 3 A DRIP entity identifier based on a HHIT, as outlined in Section 3,
embeds an identifier of the DIME in which it can be found (expected embeds an identifier of the DIME in which it can be found (expected
typically to be the USS under which the UAS is flying) and the typically to be the USS under which the UAS is flying), and the
procedures outlined in Section 5 enable Observer verification of that procedures outlined in Section 5 enable Observer verification of that
relationship. A DRIP entity identifier with suitable records in relationship. A DRIP entity identifier with suitable records in
public and private registries as outlined in Section 5 can enable public and private registries, as outlined in Section 5, can enable
lookup not only of information regarding the UAS, but also identities lookup not only of information regarding the UAS but also identities
of and pointers to information regarding the various associated of and pointers to information regarding the various associated
entities (e.g., the USS under which the UAS is flying an operation), entities (e.g., the USS under which the UAS is flying an operation),
including means of contacting those associated entities (i.e., including means of contacting those associated entities (i.e.,
locators, typically IP addresses). locators, typically IP addresses).
A suitably equipped Observer could initiate a secure communication A suitably equipped Observer could initiate a secure communication
channel, using the DET HI, to a similarly equipped and identified channel, using the DET HI, to a similarly equipped and identified
entity: the UA itself, if operating autonomously; the GCS, if the UA entity, i.e., the UA itself, if operating autonomously; the GCS, if
is remotely piloted and the necessary records have been populated in the UA is remotely piloted and the necessary records have been
DNS; the USS, etc. Assuming secure communication setup (e.g. via populated in the DNS; the USS; etc. Assuming secure communication
IPsec or HIP), arbitrary standard higher layer protocols can then be setup (e.g., via IPsec or HIP), arbitrary standard higher-layer
used for Observer to Pilot (O2P) communications (e.g., SIP [RFC3261] protocols can then be used for Observer to Pilot (O2P) communications
et seq), V2X communications (e.g., [MAVLink]), etc. Certain (e.g., SIP [RFC3261] et seq), Vehicle to Everything (V2X) (or more
preconditions are necessary: each party needs a currently usable specifically Aircraft to Anything (A2X)) communications (e.g.,
means (typically DNS) of resolving the other party's DRIP entity [MAVLink]), etc. Certain preconditions are necessary: 1) each party
identifier to a currently usable locator (IP address); and there must needs a currently usable means (typically a DNS) of resolving the
be currently usable bidirectional IP (not necessarily Internet) other party's DRIP entity identifier to a currently usable locator
connectivity between the parties. One method directly supported by (IP address), and 2) there must be currently usable bidirectional IP
the use of HHITs as DRIP entity identifiers is initiation of a HIP connectivity (not necessarily via the Internet) between the parties.
Base Exchange (BEX) and Bound End-to-End Tunnel (BEET). One method directly supported by the use of HHITs as DRIP entity
identifiers is initiation of a HIP Base Exchange (BEX) and Bound End-
to-End Tunnel (BEET).
This approach satisfies DRIP requirement GEN-6 Contact, supports This approach satisfies DRIP requirement GEN-6 Contact, supports
satisfaction of requirements [RFC9153] GEN-8, GEN-9, PRIV-2, PRIV-5 satisfaction of DRIP requirements GEN-8, GEN-9, PRIV-2, PRIV-5, and
and REG-3, and is compatible with all other DRIP requirements. REG-3 [RFC9153], and is compatible with all other DRIP requirements.
8. Security Considerations 8. IANA Considerations
The size of the public key hash in the HHIT is vulnerable to a second This document has no IANA actions.
preimage attack. It is well within current server array technology
to compute another key pair that hashes to the same HHIT (given the 9. Security Considerations
current ORCHID construction hash length to fit UAS RID and IPv6
address constraints). Thus, if a receiver were to check HHIT/HI pair The size of the public key hash in the HHIT is vulnerable to a
validity only by verifying that the received HI and associated second-preimage attack. It is well within current server array
technology to compute another key pair that hashes to the same HHIT
(given the current ORCHID construction hash length to fit UAS RID and
IPv6 address constraints). Thus, if a receiver were to check HHIT/HI
pair validity only by verifying that the received HI and associated
information, when hashed in the ORCHID construction, reproduce the information, when hashed in the ORCHID construction, reproduce the
received HHIT, an adversary could impersonate a validly registered received HHIT, an adversary could impersonate a validly registered
UA. To defend against this, online receivers should verify the UA. To defend against this, online receivers should verify the
received HHIT and received HI with the HDA (typically USS) with which received HHIT and received HI with the HDA (typically USS) with which
the HHIT/HI pair purports to be registered. Online and offline the HHIT/HI pair purports to be registered. Online and offline
receivers can use a chain of received DRIP link endorsements from a receivers can use a chain of received DRIP link endorsements from a
root of trust through the RAA and the HDA to the UA, e.g., as root of trust through the RAA and the HDA to the UA, e.g., as
described in [I-D.ietf-drip-auth] and [I-D.ietf-drip-registries]. described in [DRIP-AUTH] and [DRIP-REGISTRIES].
Compromise of a DIME private key could do widespread harm Compromise of a DIME private key could do widespread harm
[I-D.ietf-drip-registries]. In particular, it would allow bad actors [DRIP-REGISTRIES]. In particular, it would allow bad actors to
to impersonate trusted members of said DIME. These risks are in impersonate trusted members of said DIME. These risks are in
addition to those involving key management practices and will be addition to those involving key management practices and will be
addressed as part of the DIME process. All DRIP public keys can be addressed as part of the DIME process. All DRIP public keys can be
found in DNS thus they can be revoked in DNS and users SHOULD check found in the DNS, thus they can be revoked in the DNS, and users
DNS when available. Specific key revocation procedures are as yet to SHOULD check the DNS when available. Specific key revocation
be determined. procedures are as yet to be determined.
8.1. Private Key Physical Security 9.1. Private Key Physical Security
The security provided by asymmetric cryptographic techniques depends The security provided by asymmetric cryptographic techniques depends
upon protection of the private keys. It may be necessary for the GCS upon protection of the private keys. It may be necessary for the GCS
to have the key pair to register the HHIT to the USS. Thus it may be to have the key pair to register the HHIT to the USS. Thus, it may
the GCS that generates the key pair and delivers it to the UA, making be the GCS that generates the key pair and delivers it to the UA,
the GCS a part of the key security boundary. Leakage of the private making the GCS a part of the key security boundary. Leakage of the
key either from the UA or GCS to the component manufacturer is a private key, from either the UA or the GCS, to the component
valid concern and steps need to be in place to ensure safe keeping of manufacturer is a valid concern, and steps need to be in place to
the private key. Since it is possible for the UAS RID sender of a ensure safe keeping of the private key. Since it is possible for the
small harmless UA (or the entire UA) to be carried by a larger UAS RID sender of a small harmless UA (or the entire UA) to be
dangerous UA as a "false flag", it is out of scope to deal with carried by a larger dangerous UA as a "false flag", it is out of
secure storage of the private key. scope to deal with secure storage of the private key.
8.2. Quantum Resistant Cryptography 9.2. Quantum Resistant Cryptography
There has been no effort as yet in DRIP to address post quantum There has been no effort as of yet in DRIP to address post quantum
computing cryptography. Small UAS and Broadcast Remote ID computing cryptography. Small UAS and Broadcast Remote ID
communications are so constrained that current post quantum computing communications are so constrained that current post quantum computing
cryptography is not applicable. Fortunately, since a UA may use a cryptography is not applicable. Fortunately, since a UA may use a
unique HHIT for each operation, the attack window can be limited to unique HHIT for each operation, the attack window can be limited to
the duration of the operation. One potential future DRIP use for the duration of the operation. One potential future DRIP use for
post quantum cryptography is for keypairs that have long usage lives, post quantum cryptography is for key pairs that have long usage lives
but rarely if ever need to be transmitted over bandwidth constrained but that rarely, if ever, need to be transmitted over bandwidth
links; such as for Serial Numbers or Operators. As the HHIT contains constrained links, such as for serial numbers or operators. As the
the ID for the cryptographic suite used in its creation, a future HHIT contains the ID for the cryptographic suite used in its
post quantum computing safe algorithm that fits Remote ID constraints creation, a future post quantum computing safe algorithm that fits
may readily be added. This is left for future work. Remote ID constraints may be readily added. This is left for future
work.
8.3. Denial Of Service (DoS) Protection 9.3. Denial of Service (DoS) Protection
Remote ID services from the UA use a wireless link in a public space. Remote ID services from the UA use a wireless link in a public space.
As such, they are open to many forms of RF jamming. It is trivial As such, they are open to many forms of RF jamming. It is trivial
for an attacker to stop any UA messages from reaching a wireless for an attacker to stop any UA messages from reaching a wireless
receiver. Thus it is pointless to attempt to provide relief from DOS receiver. Thus, it is pointless to attempt to provide relief from
attacks as there is always the ultimate RF jamming attack. Also DOS DoS attacks, as there is always the ultimate RF jamming attack.
may be attempted with spoofing/replay attacks, for which see Also, DoS may be attempted with spoofing/replay attacks; for which,
Section 8.4. see Section 9.4.
8.4. Spoofing & Replay Protection 9.4. Spoofing & Replay Protection
As noted in Section 5, spoofing is combatted by the intrinsic self- As noted in Section 5, spoofing is combatted by the intrinsic self-
attesting properties of HHITs plus their registration. Also as noted attesting properties of HHITs, plus their registration. Also, as
in Section 5, to combat replay attacks, a receiver MUST NOT trust noted in Section 5, to combat replay attacks, a receiver MUST NOT
that an observed UA is that identified in the Basic ID message (i.e. trust any claims nominally received from an observed UA (not even the
possesses the corresponding private key) until it receives a complete Basic ID message purportedly identifying that UA) until the receiver
chain of endorsement links from a root of trust to the UA's leaf DET, verifies that the private key used to sign those claims is trusted,
plus a signed message containing frequently changing, unpredictable that the sender actually possesses that key, and that the sender
but sanity-checkable data (e.g., a Location/Vector message) and appears indeed to be that observed UA. This requires receiving a
verifies all the foregoing. complete chain of endorsement links from a root of trust to the UA's
leaf DET, plus a message containing suitable nonce-like data signed
with the private key corresponding to that DET, and verifying all the
foregoing. The term "nonce-like" describes data that is readily
available to the prover and the verifier, changes frequently, is not
predictable by the prover, and can be checked quickly at low
computational cost by the verifier; a Location/Vector message is an
obvious choice.
8.5. Timestamps & Time Sources 9.5. Timestamps & Time Sources
Section 6 and more fundamentally Section 3.3 both require timestamps. Section 6 and, more fundamentally, Section 3.3 both require
In Broadcast RID messages, [F3411-22a] specifies both 32 bit Unix timestamps. In Broadcast RID messages, [F3411-22a] specifies both
style UTC timestamps (seconds since midnight going into the 1st day 32-bit Unix-style UTC timestamps (seconds since midnight going into
of 2019 rather than 1970) and 16 bit relative timestamps (tenths of the 1st day of 2019, rather than 1970) and 16-bit relative timestamps
seconds since the start of the most recent hour or other specified (tenths of seconds since the start of the most recent hour or other
event). [F3411-22a] requires that 16 bit timestamp accuracy, specified event). [F3411-22a] requires that 16-bit timestamp
relative to the time of applicability of the data being timestamped, accuracy, relative to the time of applicability of the data being
also be reported, with a worst allowable case of 1.5 seconds. timestamped, also be reported, with a worst allowable case of 1.5
[F3411-22a] does not specify the time source, but GNSS is generally seconds. [F3411-22a] does not specify the time source, but GNSS is
assumed, as latitude, longitude and geodetic altitude must be generally assumed, as latitude, longitude, and geodetic altitude must
reported and most small UAS use GNSS for positioning and navigation. be reported and most small UAS use GNSS for positioning and
navigation.
Informative note: for example, to satisfy [FAA_RID], [F3586-22] | Informative note: For example, to satisfy [FAA_RID], [F3586-22]
specifies tamper protection of the entire RID subsystem and use of | specifies tamper protection of the entire RID subsystem and use
the US Government operated GPS. GPS has sub-microsecond accuracy | of the GPS operated by the US Government. The GPS has sub-
and 1.5 second precision. In this example, UA-sourced messages | microsecond accuracy and 1.5-second precision. In this
can be assumed to have timestamp accuracy and precision of 1.5 | example, UA-sourced messages can be assumed to have timestamp
seconds at worst. | accuracy and precision of 1.5 seconds at worst.
GCS often have access to cellular LTE or other time sources better GCS often have access to cellular LTE or other time sources better
than the foregoing, and such better time sources would be required to than the foregoing, and such better time sources would be required to
support multilateration in Section 6, but such better time sources support multilateration in Section 6, but such better time sources
cannot be assumed generally for purposes of security analysis. cannot be assumed generally for purposes of security analysis.
9. Privacy & Transparency Considerations 10. Privacy & Transparency Considerations
Broadcast RID messages can contain personal data (Section 3.2 of Broadcast RID messages can contain personal data (Section 3.2 of
[RFC6973]) such as the operator ID and in most jurisdictions must [RFC6973]), such as the operator ID, and, in most jurisdictions, must
contain the pilot/GCS location. The DRIP architectural approach for contain the pilot/GCS location. The DRIP architectural approach for
personal data protection is symmetric encryption of the personal data personal data protection is symmetric encryption of the personal data
using a session key known to the UAS and its USS, as follows. using a session key known to the UAS and its USS, as follows.
Authorized Observers obtain plaintext in either of two ways. An Authorized Observers obtain plaintext in either of two ways: 1) an
Observer can send the UAS ID and the cyphertext to a server that Observer can send the UAS ID and the cyphertext to a server that
offers decryption as a service. An Observer can send just the UAS ID offers decryption as a service, and 2) an Observer can send just the
to a server that returns the session key, so that Observer can UAS ID to a server that returns the session key so that the Observer
directly locally decrypt all cyphertext sent by that UA during that can directly, locally decrypt all cyphertext sent by that UA during
session (UAS operation). In either case, the server can be a Public that session (UAS operation). In either case, the server can be a
Safety USS, the Observer's own USS, or the UA's USS if the latter can public safety USS, the Observer's own USS, or the UA's USS if the
be determined (which under DRIP it can be, from the UAS ID itself). latter can be determined (which, under DRIP, can be from the UAS ID
Personal data is protected unless the UAS is otherwise configured: as itself). Personal data is protected unless the UAS is otherwise
part of DRIP-enhanced RID subsystem provisioning; as part of UTM configured, i.e., as part of DRIP-enhanced RID subsystem
operation authorization; or via subsequent authenticated provisioning, as part of UTM operation authorization, or via
communications from a cognizant authority. Personal data protection subsequent authenticated communications from a cognizant authority.
MUST NOT be used if the UAS loses connectivity to its USS, as if the Personal data protection MUST NOT be used if the UAS loses
UAS loses connectivity, Observers nearby likely also won't have connectivity to its USS; if the UAS loses connectivity, Observers
connectivity enabling decryption of the personal data. The UAS nearby likely also won't have connectivity enabling decryption of the
always has the option to abort the operation if personal data personal data. The UAS always has the option to abort the operation
protection is disallowed, but if this occurs during flight, the UA if personal data protection is disallowed, but if this occurs during
then MUST broadcast the personal data without protection until it flight, the UA then MUST broadcast the personal data without
lands and is powered off. Note that normative language was used only protection until it lands and is powered off. Note that normative
minimally in this section, as privacy protection requires refinement language was used only minimally in this section, as privacy
of the DRIP architecture and specification of interoperable protocol protection requires refinement of the DRIP architecture and
extensions, which are left for future DRIP documents. specification of interoperable protocol extensions, which are left
for future DRIP documents.
10. References 11. References
10.1. Normative References 11.1. Normative References
[F3411-22a] [F3411-22a]
ASTM International, "Standard Specification for Remote ID ASTM International, "Standard Specification for Remote ID
and Tracking", July 2022, and Tracking", ASTM F3411-22A, DOI 10.1520/F3411-22A, July
<https://www.astm.org/f3411-22a.html>. 2022, <https://www.astm.org/f3411-22a.html>.
[I-D.ietf-drip-rid]
Moskowitz, R., Card, S. W., Wiethuechter, A., and A.
Gurtov, "DRIP Entity Tag (DET) for Unmanned Aircraft
System Remote ID (UAS RID)", Work in Progress, Internet-
Draft, draft-ietf-drip-rid-37, 2 December 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-drip-
rid-37>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC9153] Card, S., Ed., Wiethuechter, A., Moskowitz, R., and A. [RFC9153] Card, S., Ed., Wiethuechter, A., Moskowitz, R., and A.
Gurtov, "Drone Remote Identification Protocol (DRIP) Gurtov, "Drone Remote Identification Protocol (DRIP)
Requirements and Terminology", RFC 9153, Requirements and Terminology", RFC 9153,
DOI 10.17487/RFC9153, February 2022, DOI 10.17487/RFC9153, February 2022,
<https://www.rfc-editor.org/info/rfc9153>. <https://www.rfc-editor.org/info/rfc9153>.
10.2. Informative References [RFC9374] Moskowitz, R., Card, S., Wiethuechter, A., and A. Gurtov,
"DRIP Entity Tag (DET) for Unmanned Aircraft System Remote
ID (UAS RID)", RFC 9374, DOI 10.17487/RFC9374, March 2023,
<https://www.rfc-editor.org/info/rfc9374>.
11.2. Informative References
[CTA2063A] ANSI, "Small Unmanned Aerial Systems Serial Numbers", [CTA2063A] ANSI, "Small Unmanned Aerial Systems Serial Numbers",
2019. ANSI/CTA 2063-A, September 2019.
[Delegated] [Delegated]
European Union Aviation Safety Agency (EASA), "EU European Union Aviation Safety Agency (EASA), "Commission
Commission Delegated Regulation 2019/945 of 12 March 2019 Delegated Regulation (EU) 2019/945 of 12 March 2019 on
on unmanned aircraft systems and on third-country unmanned aircraft systems and on third-country operators
operators of unmanned aircraft systems", 2019, of unmanned aircraft systems", March 2019,
<https://eur-lex.europa.eu/legal-content/EN/ <https://eur-lex.europa.eu/eli/reg_del/2019/945/oj>.
TXT/?uri=CELEX%3A32019R0945>.
[DRIP-AUTH]
Wiethuechter, A., Ed., Card, S., and R. Moskowitz, "DRIP
Entity Tag Authentication Formats & Protocols for
Broadcast Remote ID", Work in Progress, Internet-Draft,
draft-ietf-drip-auth-30, 28 March 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-drip-
auth-30>.
[DRIP-REGISTRIES]
Wiethuechter, A. and J. Reid, "DRIP Entity Tag (DET)
Identity Management Architecture", Work in Progress,
Internet-Draft, draft-ietf-drip-registries-12, 10 July
2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
drip-registries-12>.
[F3411-19] ASTM International, "Standard Specification for Remote ID
and Tracking", ASTM F3411-19, DOI 10.1520/F3411-19, May
2022, <https://www.astm.org/f3411-19.html>.
[F3586-22] ASTM International, "Standard Practice for Remote ID Means [F3586-22] ASTM International, "Standard Practice for Remote ID Means
of Compliance to Federal Aviation Administration of Compliance to Federal Aviation Administration
Regulation 14 CFR Part 89", July 2022, Regulation 14 CFR Part 89", ASTM F3586-22,
DOI 10.1520/F3586-22, July 2022,
<https://www.astm.org/f3586-22.html>. <https://www.astm.org/f3586-22.html>.
[FAA_RID] United States Federal Aviation Administration (FAA), [FAA_RID] United States Federal Aviation Administration (FAA),
"Remote Identification of Unmanned Aircraft", 2021, "Remote Identification of Unmanned Aircraft", Federal
Register, Vol. 86, No. 10, January 2021,
<https://www.govinfo.gov/content/pkg/FR-2021-01-15/ <https://www.govinfo.gov/content/pkg/FR-2021-01-15/
pdf/2020-28948.pdf>. pdf/2020-28948.pdf>.
[FAA_UAS_Concept_Of_Ops] [FAA_UAS_Concept_Of_Ops]
United States Federal Aviation Administration (FAA), United States Federal Aviation Administration (FAA),
"Unmanned Aircraft System (UAS) Traffic Management (UTM) "Unmanned Aircraft System (UAS) Traffic Management (UTM)
Concept of Operations (V2.0)", 2020, Concept of Operations", v2.0, March 2020,
<https://www.faa.gov/uas/research_development/ <https://www.faa.gov/sites/faa.gov/files/2022-08/
traffic_management/media/UTM_ConOps_v2.pdf>. UTM_ConOps_v2.pdf>.
[FS_AEUA] "Study of Further Architecture Enhancement for UAV and [FS_AEUA] "Study of Further Architecture Enhancement for UAV and
UAM", 2021, <https://www.3gpp.org/ftp/tsg_sa/WG2_Arch/ UAM", S2-2107092, October 2021,
<https://www.3gpp.org/ftp/tsg_sa/WG2_Arch/
TSGS2_147E_Electronic_2021-10/Docs/S2-2107092.zip>. TSGS2_147E_Electronic_2021-10/Docs/S2-2107092.zip>.
[I-D.ietf-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-29, 15 February 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-drip-
auth-29>.
[I-D.ietf-drip-registries]
Wiethuechter, A. and J. Reid, "DRIP Entity Tag (DET)
Identity Management Architecture", Work in Progress,
Internet-Draft, draft-ietf-drip-registries-07, 5 December
2022, <https://datatracker.ietf.org/doc/html/draft-ietf-
drip-registries-07>.
[Implementing] [Implementing]
European Union Aviation Safety Agency (EASA), "EU European Union Aviation Safety Agency (EASA), "Commission
Commission Implementing Regulation 2019/947 of 24 May 2019 Implementing Regulation (EU) 2019/947 of 24 May 2019 on
on the rules and procedures for the operation of unmanned the rules and procedures for the operation of unmanned
aircraft", 2019, <https://eur-lex.europa.eu/legal- aircraft (Text with EEA relevance.)", May 2019,
content/EN/TXT/?uri=CELEX%3A32019R0947>. <https://eur-lex.europa.eu/legal-content/EN/
TXT/?uri=CELEX%3A32019R0947>.
[Implementing_update] [Implementing_update]
European Union Aviation Safety Agency (EASA), "EU European Union Aviation Safety Agency (EASA), "Commission
COMMISSION IMPLEMENTING REGULATION (EU) 2021/664 of 22 Implementing Regulation (EU) 2021/664 of 22 April 2021 on
April 2021 on a regulatory framework for the U-space", a regulatory framework for the U-space (Text with EEA
2021, <https://eur-lex.europa.eu/legal-content/EN/ relevance)", April 2021, <https://eur-lex.europa.eu/legal-
TXT/?uri=CELEX%3A32021R0664>. content/EN/TXT/?uri=CELEX%3A32021R0664>.
[LAANC] United States Federal Aviation Administration (FAA), "Low [LAANC] United States Federal Aviation Administration (FAA), "Low
Altitude Authorization and Notification Capability", n.d., Altitude Authorization and Notification Capability",
<https://www.faa.gov/uas/programs_partnerships/ <https://www.faa.gov/
data_exchange/>. air_traffic/publications/atpubs/foa_html/
chap12_section_9.html>.
[MAVLink] "Micro Air Vehicle Communication Protocol", 2021, [MAVLink] MAVLink, "Micro Air Vehicle Communication Protocol",
<http://mavlink.io/>. <http://mavlink.io/>.
[MOC-NOA] United States Federal Aviation Administration (FAA), [MOC-NOA] United States Federal Aviation Administration (FAA),
"Accepted Means of Compliance; Remote Identification of "Accepted Means of Compliance; Remote Identification of
Unmanned Aircraft", August 2022, Unmanned Aircraft", Document ID FAA-2022-0859-0001, August
2022,
<https://www.regulations.gov/document/FAA-2022-0859-0001>. <https://www.regulations.gov/document/FAA-2022-0859-0001>.
[NPA] European Union Aviation Safety Agency (EASA), "Notice of [NPA] European Union Aviation Safety Agency (EASA), "Notice of
Proposed Amendment 2021-14 Development of acceptable means Proposed Amendment 2021-14: Development of acceptable
of compliance and guidance material to support the U-space means of compliance and guidance material to support the
regulation", 2021, U-space regulation", December 2021,
<https://www.easa.europa.eu/downloads/134303/en>. <https://www.easa.europa.eu/downloads/134303/en>.
[NPRM] United States Federal Aviation Administration (FAA), [NPRM] United States Federal Aviation Administration (FAA),
"Notice of Proposed Rule Making on Remote Identification "Remote Identification of Unmanned Aircraft Systems",
of Unmanned Aircraft Systems", 2019. Notice of proposed rulemaking, December 2019,
<https://www.federalregister.gov/documents/2019/
12/31/2019-28100/remote-identification-of-unmanned-
aircraft-systems>.
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities", [RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
<https://www.rfc-editor.org/info/rfc1034>. <https://www.rfc-editor.org/info/rfc1034>.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E. A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261, Schooler, "SIP: Session Initiation Protocol", RFC 3261,
DOI 10.17487/RFC3261, June 2002, DOI 10.17487/RFC3261, June 2002,
<https://www.rfc-editor.org/info/rfc3261>. <https://www.rfc-editor.org/info/rfc3261>.
skipping to change at page 27, line 32 skipping to change at line 1255
[RFC8005] Laganier, J., "Host Identity Protocol (HIP) Domain Name [RFC8005] Laganier, J., "Host Identity Protocol (HIP) Domain Name
System (DNS) Extension", RFC 8005, DOI 10.17487/RFC8005, System (DNS) Extension", RFC 8005, DOI 10.17487/RFC8005,
October 2016, <https://www.rfc-editor.org/info/rfc8005>. October 2016, <https://www.rfc-editor.org/info/rfc8005>.
[RFC8032] Josefsson, S. and I. Liusvaara, "Edwards-Curve Digital [RFC8032] Josefsson, S. and I. Liusvaara, "Edwards-Curve Digital
Signature Algorithm (EdDSA)", RFC 8032, Signature Algorithm (EdDSA)", RFC 8032,
DOI 10.17487/RFC8032, January 2017, DOI 10.17487/RFC8032, January 2017,
<https://www.rfc-editor.org/info/rfc8032>. <https://www.rfc-editor.org/info/rfc8032>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC9082] Hollenbeck, S. and A. Newton, "Registration Data Access [RFC9082] Hollenbeck, S. and A. Newton, "Registration Data Access
Protocol (RDAP) Query Format", STD 95, RFC 9082, Protocol (RDAP) Query Format", STD 95, RFC 9082,
DOI 10.17487/RFC9082, June 2021, DOI 10.17487/RFC9082, June 2021,
<https://www.rfc-editor.org/info/rfc9082>. <https://www.rfc-editor.org/info/rfc9082>.
[RFC9083] Hollenbeck, S. and A. Newton, "JSON Responses for the [RFC9083] Hollenbeck, S. and A. Newton, "JSON Responses for the
Registration Data Access Protocol (RDAP)", STD 95, Registration Data Access Protocol (RDAP)", STD 95,
RFC 9083, DOI 10.17487/RFC9083, June 2021, RFC 9083, DOI 10.17487/RFC9083, June 2021,
<https://www.rfc-editor.org/info/rfc9083>. <https://www.rfc-editor.org/info/rfc9083>.
[RFC9224] Blanchet, M., "Finding the Authoritative Registration Data [RFC9224] Blanchet, M., "Finding the Authoritative Registration Data
Access Protocol (RDAP) Service", STD 95, RFC 9224, Access Protocol (RDAP) Service", STD 95, RFC 9224,
DOI 10.17487/RFC9224, March 2022, DOI 10.17487/RFC9224, March 2022,
<https://www.rfc-editor.org/info/rfc9224>. <https://www.rfc-editor.org/info/rfc9224>.
[RFC9334] Birkholz, H., Thaler, D., Richardson, M., Smith, N., and [RFC9334] Birkholz, H., Thaler, D., Richardson, M., Smith, N., and
W. Pan, "Remote ATtestation procedureS (RATS) W. Pan, "Remote ATtestation procedureS (RATS)
Architecture", RFC 9334, DOI 10.17487/RFC9334, January Architecture", RFC 9334, DOI 10.17487/RFC9334, January
2023, <https://www.rfc-editor.org/info/rfc9334>. 2023, <https://www.rfc-editor.org/info/rfc9334>.
[TR-22.825]
3GPP, "Study on Remote Identification of Unmanned Aerial
Systems (UAS)", Release 16, 3GPP TR 22.825, September
2018,
<https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3527>.
[TR-23.755] [TR-23.755]
3GPP, "Study on application layer support for Unmanned 3GPP, "Study on application layer support for Unmanned
Aerial Systems (UAS) (Release 17)", 2019, Aerial Systems (UAS)", Release 17, 3GPP TR 23.755, March
2021,
<https://portal.3gpp.org/desktopmodules/Specifications/ <https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3588>. SpecificationDetails.aspx?specificationId=3588>.
[TS-22.825]
3GPP, "Study on Remote Identification of Unmanned Aerial
Systems (UAS)", 2018,
<https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3527>.
[TS-23.255] [TS-23.255]
3GPP, "Application layer support for Uncrewed Aerial 3GPP, "Application layer support for Uncrewed Aerial
System (UAS) Functional architecture and information System (UAS); Functional architecture and information
flows; (Release 17)", 2020, flows", Release 17, 3GPP TS 23.255, June 2021,
<https://portal.3gpp.org/desktopmodules/Specifications/ <https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3843>. SpecificationDetails.aspx?specificationId=3843>.
[U-Space] European Organization for the Safety of Air Navigation [U-Space] European Organization for the Safety of Air Navigation
(EUROCONTROL), "U-space Concept of Operations", 2019, (EUROCONTROL), "U-space Concept of Operations", October
2019,
<https://www.sesarju.eu/sites/default/files/documents/u- <https://www.sesarju.eu/sites/default/files/documents/u-
space/CORUS%20ConOps%20vol2.pdf>. space/CORUS%20ConOps%20vol2.pdf>.
Appendix A. Overview of Unmanned Aircraft Systems (UAS) Traffic Appendix A. Overview of UAS Traffic Management (UTM)
Management (UTM)
A.1. Operation Concept A.1. Operation Concept
The National Aeronautics and Space Administration (NASA) and FAA's The efforts of the National Aeronautics and Space Administration
effort to integrate UAS operations into the national airspace system (NASA) and FAA to integrate UAS operations into the national airspace
(NAS) led to the development of the concept of UTM and the ecosystem system (NAS) led to the development of the concept of UTM and the
around it. The UTM concept was initially presented in 2013 and ecosystem around it. The UTM concept was initially presented in
version 2.0 was published in 2020 [FAA_UAS_Concept_Of_Ops]. 2013, and version 2.0 was published in 2020 [FAA_UAS_Concept_Of_Ops].
The eventual concept refinement, initial prototype implementation, The eventual concept refinement, initial prototype implementation,
and testing were conducted by the joint FAA and NASA UTM research and testing were conducted by the joint FAA and NASA UTM research
transition team. World efforts took place afterward. The Single transition team. World efforts took place afterward. The Single
European Sky ATM Research (SESAR) started the CORUS project to European Sky ATM Research (SESAR) started the Concept of Operation
research its UTM counterpart concept, namely [U-Space]. This effort for EuRopean UTM Systems (CORUS) project to research its UTM
is led by the European Organization for the Safety of Air Navigation counterpart concept, namely [U-Space]. This effort is led by the
(Eurocontrol). European Organization for the Safety of Air Navigation (EUROCONTROL).
Both NASA and SESAR have published their UTM concepts of operations Both NASA and SESAR have published their UTM concepts of operations
to guide the development of their future air traffic management (ATM) to guide the development of their future air traffic management (ATM)
system and ensure safe and efficient integration of manned and system and ensure safe and efficient integration of manned and
unmanned aircraft into the national airspace. unmanned aircraft into the national airspace.
UTM comprises UAS operations infrastructure, procedures and local UTM comprises UAS operations infrastructure, procedures, and local
regulation compliance policies to guarantee safe UAS integration and regulation compliance policies to guarantee safe UAS integration and
operation. The main functionality of UTM includes, but is not operation. The main functionality of UTM includes, but is not
limited to, providing means of communication between UAS operators limited to, providing means of communication between UAS operators
and service providers and a platform to facilitate communication and service providers and a platform to facilitate communication
among UAS service providers. among UAS service providers.
A.2. UAS Service Supplier (USS) A.2. UAS Service Supplier (USS)
A USS plays an important role to fulfill the key performance A USS plays an important role to fulfill the key performance
indicators (KPIs) that UTM has to offer. Such an Entity acts as a indicators (KPIs) that UTM has to offer. Such an entity acts as a
proxy between UAS operators and UTM service providers. It provides proxy between UAS operators and UTM service providers. It provides
services like real-time UAS traffic monitoring and planning, services like real-time UAS traffic monitoring and planning,
aeronautical data archiving, airspace and violation control, aeronautical data archiving, airspace and violation control,
interacting with other third-party control entities, etc. A USS can interacting with other third-party control entities, etc. A USS can
coexist with other USS to build a large service coverage map that can coexist with other USS to build a large service coverage map that can
load-balance, relay, and share UAS traffic information. load-balance, relay, and share UAS traffic information.
The FAA works with UAS industry shareholders and promotes the Low The FAA works with UAS industry shareholders and promotes the Low
Altitude Authorization and Notification Capability [LAANC] program, Altitude Authorization and Notification Capability [LAANC] program,
which is the first system to realize some of the envisioned which is the first system to realize some of the envisioned
functionality of UTM. The LAANC program can automate UAS operational functionality of UTM. The LAANC program can automate UAS operational
intent (flight plan) submission and application for airspace intent (flight plan) submissions and applications for airspace
authorization in real-time by checking against multiple aeronautical authorization in real time by checking against multiple aeronautical
databases such as airspace classification and operating rules databases, such as airspace classification and operating rules
associated with it, FAA UAS facility map, special use airspace, associated with it, the FAA UAS facility map, special use airspace,
Notice to Airmen (NOTAM), and Temporary Flight Restriction (TFR). Notice to Airmen (NOTAM), and Temporary Flight Restriction (TFR).
A.3. UTM Use Cases for UAS Operations A.3. UTM Use Cases for UAS Operations
This section illustrates a couple of use case scenarios where UAS This section illustrates a couple of use case scenarios where UAS
participation in UTM has significant safety improvement. participation in UTM has significant safety improvement.
1. For a UAS participating in UTM and taking off or landing in 1. For a UAS participating in UTM and taking off or landing in
controlled airspace (e.g., Class Bravo, Charlie, Delta, and Echo controlled airspace (e.g., Class Bravo, Charlie, Delta, and Echo
in the United States), the USS under which the UAS is operating in the United States), the USS under which the UAS is operating
is responsible for verifying UA registration, authenticating the is responsible for verifying UA registration, authenticating the
UAS operational intent (flight plan) by checking against a UAS operational intent (flight plan) by checking against a
designated UAS facility map database, obtaining the air traffic designated UAS facility map database, obtaining the air traffic
control (ATC) authorization, and monitoring the UAS flight path control (ATC) authorization, and monitoring the UAS flight path
in order to maintain safe margins and follow the pre-authorized in order to maintain safe margins and follow the pre-authorized
sequence of authorized 4-D volumes (route). sequence of authorized 4-D volumes (route).
2. For a UAS participating in UTM and taking off or landing in 2. For a UAS participating in UTM and taking off or landing in
uncontrolled airspace (e.g., Class Golf in the United States), uncontrolled airspace (e.g., Class Golf in the United States),
pre-flight authorization must be obtained from a USS when preflight authorization must be obtained from a USS when
operating Beyond Visual Line Of Sight (BVLOS). The USS either operating BVLOS. The USS either accepts or rejects the received
accepts or rejects the received operational intent (flight plan) operational intent (flight plan) from the UAS. An accepted UAS
from the UAS. An accepted UAS operation may, and in some cases operation may, and in some cases must, share its current flight
must, share its current flight data, such as GPS position and data, such as GPS position and altitude, to the USS. The USS may
altitude, to the USS. The USS may maintain (and provide to maintain (and provide to authorized requestors) the UAS operation
authorized requestors) the UAS operation status near real-time in status near real time in the short term and may retain at least
the short term, and may retain at least some of it in the longer some of it in the longer term, e.g., for overall airspace air
term, e.g., for overall airspace air traffic monitoring. traffic monitoring.
Appendix B. Automatic Dependent Surveillance Broadcast (ADS-B) Appendix B. Automatic Dependent Surveillance Broadcast (ADS-B)
The ADS-B is the de jure technology used in manned aviation for ADS-B is the de jure technology used in manned aviation for sharing
sharing location information, from the aircraft to ground and location information, from the aircraft to ground and satellite-based
satellite-based systems, designed in the early 2000s. Broadcast RID systems, designed in the early 2000s. Broadcast RID is conceptually
is conceptually similar to ADS-B, but with the receiver target being similar to ADS-B but with the receiver target being the general
the general public on generally available devices (e.g., public on generally available devices (e.g., smartphones).
smartphones).
For numerous technical reasons, ADS-B itself is not suitable for low- For numerous technical reasons, ADS-B itself is not suitable for low-
flying small UAS. Technical reasons include but are not limited to flying, small UAS. Technical reasons include, but are not limited
the following: to, the following:
1. Lack of support for the 1090 MHz ADS-B channel on any consumer 1. lack of support for the 1090-MHz ADS-B channel on any consumer
handheld devices handheld devices
2. Cost, Size, Weight and Power (CSWaP) requirements of ADS-B 2. Cost, Size, Weight, and Power (CSWaP) requirements of ADS-B
transponders on CSWaP constrained UA transponders on CSWaP-constrained UA
3. Limited bandwidth of both uplink and downlink, which would likely 3. limited bandwidth of both uplink and downlink, which would likely
be saturated by large numbers of UAS, endangering manned aviation be saturated by large numbers of UAS, endangering manned aviation
Understanding these technical shortcomings, regulators worldwide have Understanding these technical shortcomings, regulators worldwide have
ruled out the use of ADS-B for the small UAS for which UAS RID and ruled out the use of ADS-B for the small UAS for which UAS RID and
DRIP are intended. DRIP are intended.
Acknowledgments Acknowledgments
The work of the FAA's UAS Identification and Tracking (UAS ID) The work of the FAA's UAS Identification and Tracking (UAS ID)
Aviation Rulemaking Committee (ARC) is the foundation of later ASTM Aviation Rulemaking Committee (ARC) is the foundation of later ASTM
and IETF DRIP WG efforts. The work of ASTM F38.02 in balancing the and IETF DRIP WG efforts. The work of ASTM F38.02 in balancing the
interests of diverse stakeholders is essential to the necessary rapid interests of diverse stakeholders is essential to the necessary rapid
and widespread deployment of UAS RID. Thanks to Alexandre Petrescu, and widespread deployment of UAS RID. Thanks to Alexandre Petrescu,
Stephan Wenger, Kyle Rose, Roni Even, Thomas Fossati, Valery Smyslov, Stephan Wenger, Kyle Rose, Roni Even, Thomas Fossati, Valery Smyslov,
Erik Kline, John Scudder, Murray Kucheraway, Robert Wilton, Roman Erik Kline, John Scudder, Murray Kucheraway, Robert Wilton, Roman
Daniliw, Warren Kumari, Zaheduzzaman Sarker and Dave Thaler for the Daniliw, Warren Kumari, Zaheduzzaman Sarker, and Dave Thaler for the
reviews and helpful positive comments. Thanks to Laura Welch for her reviews and helpful positive comments. Thanks to Laura Welch for her
assistance greatly improving this document. Thanks to Dave Thaler assistance in greatly improving this document. Thanks to Dave Thaler
for showing our authors how to leverage the RATS model for for showing our authors how to leverage the RATS model for
attestation in DRIP. Thanks to chairs Daniel Migault and Mohamed attestation in DRIP. Thanks to chairs Daniel Migault and Mohamed
Boucadair for direction of our team of authors and editor, some of Boucadair for direction of our team of authors and editors, some of
whom are relative newcomers to writing IETF documents. Thanks whom are relative newcomers to writing IETF documents. Thanks
especially to Internet Area Director Eric Vyncke for guidance and especially to Internet Area Director Éric Vyncke for guidance and
support. support.
Authors' Addresses Authors' Addresses
Stuart W. Card Stuart W. Card
AX Enterprize AX Enterprize
4947 Commercial Drive 4947 Commercial Drive
Yorkville, NY, 13495 Yorkville, NY 13495
United States of America United States of America
Email: stu.card@axenterprize.com Email: stu.card@axenterprize.com
Adam Wiethuechter Adam Wiethuechter
AX Enterprize AX Enterprize
4947 Commercial Drive 4947 Commercial Drive
Yorkville, NY, 13495 Yorkville, NY 13495
United States of America United States of America
Email: adam.wiethuechter@axenterprize.com Email: adam.wiethuechter@axenterprize.com
Robert Moskowitz Robert Moskowitz
HTT Consulting HTT Consulting
Oak Park, MI, 48237 Oak Park, MI 48237
United States of America United States of America
Email: rgm@labs.htt-consult.com Email: rgm@labs.htt-consult.com
Shuai Zhao Shuai Zhao (editor)
Intel Intel
2200 Mission College Blvd 2200 Mission College Blvd.
Santa Clara, 95054 Santa Clara, 95054
United States of America United States of America
Email: shuai.zhao@ieee.org Email: shuai.zhao@ieee.org
Andrei Gurtov Andrei Gurtov
Linköping University Linköping University
IDA IDA
SE-58183 Linköping Linköping SE-58183 Linköping
Sweden Sweden
Email: gurtov@acm.org Email: gurtov@acm.org
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