draft-ietf-drip-arch-17.txt   draft-ietf-drip-arch-18.txt 
drip S. Card drip S. Card
Internet-Draft A. Wiethuechter Internet-Draft A. Wiethuechter
Intended status: Informational AX Enterprize Intended status: Informational AX Enterprize
Expires: 14 May 2022 R. Moskowitz Expires: 17 June 2022 R. Moskowitz
HTT Consulting HTT Consulting
S. Zhao (Editor) S. Zhao (Editor)
Tencent Tencent
A. Gurtov A. Gurtov
Linköping University Linköping University
10 November 2021 14 December 2021
Drone Remote Identification Protocol (DRIP) Architecture Drone Remote Identification Protocol (DRIP) Architecture
draft-ietf-drip-arch-17 draft-ietf-drip-arch-18
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 Remote Identification and tracking support Unmanned Aircraft System Remote Identification and tracking
(UAS RID), plus RID-related communications. This architecture (UAS RID), plus RID-related communications. This architecture
adheres to the requirements listed in the DRIP Requirements document. adheres to the requirements listed in the DRIP Requirements document.
Status of This Memo Status of This Memo
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on 14 May 2022. This Internet-Draft will expire on 17 June 2022.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/ Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document. license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
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1.1. Overview of Unmanned Aircraft System (UAS) Remote ID (RID) 1.1. Overview of Unmanned Aircraft System (UAS) Remote ID (RID)
and Standardization . . . . . . . . . . . . . . . . . . . 3 and Standardization . . . . . . . . . . . . . . . . . . . 3
1.2. Overview of Types of UAS Remote ID . . . . . . . . . . . 4 1.2. Overview of Types of UAS Remote ID . . . . . . . . . . . 4
1.2.1. Broadcast RID . . . . . . . . . . . . . . . . . . . . 4 1.2.1. Broadcast RID . . . . . . . . . . . . . . . . . . . . 4
1.2.2. Network RID . . . . . . . . . . . . . . . . . . . . . 5 1.2.2. Network RID . . . . . . . . . . . . . . . . . . . . . 5
1.3. Overview of USS Interoperability . . . . . . . . . . . . 7 1.3. Overview of USS Interoperability . . . . . . . . . . . . 7
1.4. Overview of DRIP Architecture . . . . . . . . . . . . . . 8 1.4. Overview of DRIP Architecture . . . . . . . . . . . . . . 8
2. Terms and Definitions . . . . . . . . . . . . . . . . . . . . 10 2. Terms and Definitions . . . . . . . . . . . . . . . . . . . . 10
2.1. Architecture Terminology . . . . . . . . . . . . . . . . 10 2.1. Architecture Terminology . . . . . . . . . . . . . . . . 10
2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 10 2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 10
2.3. Additional Definitions . . . . . . . . . . . . . . . . . 10 2.3. Claims, Assertions, Attestations, and Certificates . . . 10
3. Claims, Assertions, Attestations, and Certificates . . . . . 10 2.4. Additional Definitions . . . . . . . . . . . . . . . . . 11
4. HHIT as the DRIP Entity Identifier . . . . . . . . . . . . . 11 3. HHIT as the DRIP Entity Identifier . . . . . . . . . . . . . 11
4.1. UAS Remote Identifiers Problem Space . . . . . . . . . . 12 3.1. UAS Remote Identifiers Problem Space . . . . . . . . . . 12
4.2. HHIT as A Trustworthy DRIP Entity Identifier . . . . . . 12 3.2. HHIT as A Trustworthy DRIP Entity Identifier . . . . . . 12
4.3. HHIT for DRIP Identifier Registration and Lookup . . . . 14 3.3. HHIT for DRIP Identifier Registration and Lookup . . . . 14
4.4. HHIT as a Cryptographic Identifier . . . . . . . . . . . 14 3.4. HHIT as a Cryptographic Identifier . . . . . . . . . . . 14
5. DRIP Identifier Registration and Registries . . . . . . . . . 14 4. DRIP Identifier Registration and Registries . . . . . . . . . 14
5.1. Public Information Registry . . . . . . . . . . . . . . . 15 4.1. Public Information Registry . . . . . . . . . . . . . . . 15
5.1.1. Background . . . . . . . . . . . . . . . . . . . . . 15 4.1.1. Background . . . . . . . . . . . . . . . . . . . . . 15
5.1.2. DNS as the Public DRIP Identifier Registry . . . . . 15 4.1.2. DNS as the Public DRIP Identifier Registry . . . . . 15
5.2. Private Information Registry . . . . . . . . . . . . . . 15 4.2. Private Information Registry . . . . . . . . . . . . . . 15
5.2.1. Background . . . . . . . . . . . . . . . . . . . . . 15 4.2.1. Background . . . . . . . . . . . . . . . . . . . . . 15
5.2.2. EPP and RDAP as the Private DRIP Identifier 4.2.2. EPP and RDAP as the Private DRIP Identifier
Registry . . . . . . . . . . . . . . . . . . . . . . 16 Registry . . . . . . . . . . . . . . . . . . . . . . 16
5.2.3. Alternative Private DRIP Registry methods . . . . . . 16 4.2.3. Alternative Private DRIP Registry methods . . . . . . 16
6. DRIP Identifier Trust . . . . . . . . . . . . . . . . . . . . 16 5. DRIP Identifier Trust . . . . . . . . . . . . . . . . . . . . 16
7. Harvesting Broadcast Remote ID messages for UTM Inclusion . . 17 6. Harvesting Broadcast Remote ID messages for UTM Inclusion . . 17
7.1. The CS-RID Finder . . . . . . . . . . . . . . . . . . . . 18 6.1. The CS-RID Finder . . . . . . . . . . . . . . . . . . . . 18
7.2. The CS-RID SDSP . . . . . . . . . . . . . . . . . . . . . 18 6.2. The CS-RID SDSP . . . . . . . . . . . . . . . . . . . . . 18
8. DRIP Contact . . . . . . . . . . . . . . . . . . . . . . . . 18 7. DRIP Contact . . . . . . . . . . . . . . . . . . . . . . . . 18
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
10. Security Considerations . . . . . . . . . . . . . . . . . . . 19 9. Security Considerations . . . . . . . . . . . . . . . . . . . 19
11. Privacy & Transparency Considerations . . . . . . . . . . . . 19 10. Privacy & Transparency Considerations . . . . . . . . . . . . 19
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
12.1. Normative References . . . . . . . . . . . . . . . . . . 20 11.1. Normative References . . . . . . . . . . . . . . . . . . 20
12.2. Informative References . . . . . . . . . . . . . . . . . 20 11.2. Informative References . . . . . . . . . . . . . . . . . 20
Appendix A. Overview of Unmanned Aircraft Systems (UAS) Traffic Appendix A. Overview of Unmanned Aircraft Systems (UAS) Traffic
Management (UTM) . . . . . . . . . . . . . . . . . . . . 23 Management (UTM) . . . . . . . . . . . . . . . . . . . . 23
A.1. Operation Concept . . . . . . . . . . . . . . . . . . . . 23 A.1. Operation Concept . . . . . . . . . . . . . . . . . . . . 23
A.2. UAS Service Supplier (USS) . . . . . . . . . . . . . . . 24 A.2. UAS Service Supplier (USS) . . . . . . . . . . . . . . . 24
A.3. UTM Use Cases for UAS Operations . . . . . . . . . . . . 24 A.3. UTM Use Cases for UAS Operations . . . . . . . . . . . . 24
Appendix B. Automatic Dependent Surveillance Broadcast Appendix B. Automatic Dependent Surveillance Broadcast
(ADS-B) . . . . . . . . . . . . . . . . . . . . . . . . . 25 (ADS-B) . . . . . . . . . . . . . . . . . . . . . . . . . 25
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 25 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25
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rule [FAA_RID] as "a potential means of compliance" to a Remote ID rule [FAA_RID] as "a potential means of compliance" to a Remote ID
rule. rule.
The 3rd Generation Partnership Project (3GPP) The 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 [TS-22.825] and proposed a set of use cases in the mobile network
and the services that can be offered based on RID. Release 17 and the services that can be offered based on RID. Release 17
specification focuses on enhanced UAS service requirements and specification focuses on enhanced UAS service requirements and
provides the protocol and application architecture support that provides the protocol and application architecture support that
will be applicable for both 4G and 5G networks. will be applicable for both 4G and 5G networks. The study of
Further Architecture Enhancement for Uncrewed Aerial Vehicles
(UAV) and Urban Air Mobility (UAM) [FS_AEUA] in release 18 further
enhances the communication mechanism between UAS and USS/UTM. The
RID discussed in Section 3 may be used as the 3GPP CAA-level ID
for Remote Identification purposes.
1.2. Overview of Types of UAS Remote ID 1.2. Overview of Types of UAS Remote ID
1.2.1. Broadcast RID 1.2.1. Broadcast RID
[F3411] defines a set of RID messages for direct, one-way, broadcast [F3411] defines a set of RID messages for direct, one-way, broadcast
transmissions from the UA over Bluetooth or Wi-Fi. These are transmissions from the UA over Bluetooth or Wi-Fi. These are
currently defined as MAC-Layer messages. Internet (or other Wide currently defined as MAC-Layer messages. Internet (or other Wide
Area Network) connectivity is only needed for UAS registry Area Network) connectivity is only needed for UAS registry
information lookup by Observers using the directly received UAS ID. information lookup by Observers using the directly received UAS ID.
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| Observer's device (e.g., smartphone) | | Observer's device (e.g., smartphone) |
+--------------------------------------+ +--------------------------------------+
Figure 1 Figure 1
Broadcast RID provides information only about unmanned aircraft (UA) Broadcast RID provides information only about unmanned aircraft (UA)
within direct RF LOS, typically similar to visual Light-Of-Sight within direct RF LOS, typically similar to visual Light-Of-Sight
(LOS), with a range up to approximately 1 km. This information may (LOS), with a range up to approximately 1 km. This information may
be 'harvested' from received broadcasts and made available via the be 'harvested' from received broadcasts and made available via the
Internet, enabling surveillance of areas too large for local direct Internet, enabling surveillance of areas too large for local direct
visual observation or direct RF link based ID (see Section 7). visual observation or direct RF link based ID (see Section 6).
1.2.2. Network RID 1.2.2. Network RID
[F3411], using the same data dictionary that is the basis of [F3411], 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 RID is generated by the UAS * The information to be reported via RID is generated by the UAS
(typically some by the UA and some by the GCS, e.g. their (typically some by the UA and some by the GCS, e.g. their
respective GNSS derived locations). respective GNSS derived locations).
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* 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 SP that have operations in volumes Net-RID DP queries all Net-RID SP 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 SP and responds to the Observer's query. RID SP 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:
+-------------+ ****************** +-------------+ ******************
| UA | * Internet * | UA | * Internet *
+--o-------o--+ * * +--o-------o--+ * *
| | * * | | * *
| | * * +------------+ | | * * +------------+
| '--------*--(+)-----------*-----o | | '--------*--(+)-----------*-----o |
| * | * | | | * | * | |
| .--------*--(+)-----------*-----o NET-RID SP | | .--------*--(+)-----------*-----o NET-RID SP |
| | * * | | | | * * | |
| | * .------*-----o | | | * .------*-----o |
| | * | * +------------+ | | * | * +------------+
| | * | * | | * | *
| | * | * +------------+ | | * | * +------------+
| | * '------*-----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
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 of 2021) typically a direct RF link, but path, currently (in the year of 2021) typically a direct RF link, but
with increasing beyond Visual Line of Sight (BVLOS) operations with increasing beyond Visual Line of Sight (BVLOS) operations
expected often to be wireless links at either end with the Internet expected often to be wireless links at either end with the Internet
between. between.
Telemetry (at least UA's position and heading) flows from the UA to Telemetry (at least UA's position and heading) flows from the UA to
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UAS and the Net-RID SP, and/or between the Net-RID DP and Observer UAS and the Net-RID SP, and/or between the Net-RID DP and Observer
devices. devices.
Informative note: Neither link layer protocols nor the use of Informative note: Neither link layer protocols nor the use of
links (e.g., the link often existing between the GCS and the links (e.g., the link often existing between the GCS and the
UA) for any purpose other than carriage of RID information is UA) for any purpose other than carriage of RID information is
in the scope of [F3411] Network RID. in the scope of [F3411] Network RID.
1.3. Overview of USS Interoperability 1.3. Overview of USS Interoperability
With Net-RID, there is direct communication between the UAS and its With Net-RID, there is direct communication between each UAS and its
USS. With Broadcast-RID and UTM, the UAS Operator has either pre- USS. Multiple USS exchange information with the assistance of a
filed a 4D space volume for USS operational knowledge and/or Discovery and Synchronization Service (DSS) so all USS collectively
Observers can be providing information about observed UA to a have knowledge about all activities in a 4D airspace.
Surveillance Supplemental Data Service Provider (SDSP). USS exchange
information via a Discovery and Synchronization Service (DSS) so all
USS collectively have knowledge about all activities in a 4D
airspace.
The interactions among Observer, UA, and USS are shown in Figure 3. The interactions among an Observer, multiple UAS, and their USS are
shown in Figure 3.
+----------+ +------+ +----------+ +------+
| Observer | | UAS1 | | Observer | | UAS2 |
+----------+ +----o-+ +-----o----+ +-o----+
/ \ | | |
/ \ | | |
+------+ +------+ ******|*************|************|******
| UAS1 | | UAS2 | * | | | *
+------+ +------+ * | +---o--+ | *
\ / * | .------o USS3 o------. | *
\ / * | | +--o---+ | | *
+----------+ * | | | | | *
| Internet | * +-o--o-+ +--o--+ +-o--o-+ *
+----------+ * | o----o DSS o-----o | *
/ \ * | USS1 | +-----+ | USS2 | *
/ \ * | o----------------o | *
+------+ +------+ * +------+ +------+ *
| USS1 | <-------> | USS2 | * *
+------+ +------+ * Internet *
\ / ****************************************
\ /
+------+
| DSS |
+------+
Figure 3 Figure 3
Editor-note-1: (Stu) re-draw this figure and propose text. Then
double check the langauge in Editor-note-8
1.4. Overview of DRIP Architecture 1.4. Overview of DRIP Architecture
Figure 4 illustrates a brief summary of the general UAS RID usage Figure 4 illustrates the general UAS RID usage scenario. Broadcast
scenarios in DRIP. RID 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.
Figure 4 shows, as context, some entities and interfaces beyond the
scope of DRIP (as currently (2022) chartered).
General x x Public *************** ***************
Public xxxxx xxxxx Safety * UAS1 * * UAS2 *
Observer x x Observer * * * *
x x * +--------+ * DAA/V2V * +--------+ *
x x ---------+ +---------- x x * | UA o--*----------------------------------------*--o UA | *
x x | | x x * +--o--o--+ * * +--o--o--+ *
| | * | | * +------+ Lookups +------+ * | | *
UA1 x x | | +------------ x x UA2 * | | * | GPOD o------. .------o PSOD | * | | *
xxxxx | | | xxxxx * | | * +------+ | | +------+ * | | *
| + + + | * | | * | | * | | *
| xxxxxxxxxx | * C2 | | * V2I ************ V2I * | | C2 *
| x x | * | '-----*--------------* *--------------*-----' | *
+----------+x Internet x+------------+ * | * * * * | *
UA1 | x x | UA1 * | o====NetRID====* *====NetRID====o | *
Pilot x | xxxxxxxxxx | x Pilot * +--o--+ * * Internet * * +--o--+ *
Operator xxxxx + + + xxxxx Operator * | GCS o-----*--------------* *--------------*-----o GCS | *
GCS1 x | | | x GCS2 * +-----+ * Registration * * Registration * +-----+ *
x | | | x * * (and UTM) * * (and UTM) * *
x x | | | x x *************** ************ ***************
x x | | | x x | | |
| | | +----------+ | | | +----------+
+----------+ | | | +----------+ | Public o---' | '---o Private |
| |------+ | +-------| | | Registry | | | Registry |
| Public | | | Private | +----------+ | +----------+
| Registry | +-----+ | Registry | +--o--+
| | | DNS | | | | DNS |
+----------+ +-----+ +----------+ +-----+
Figure 4 GPOD: General Public Observer Device (for brevity in this figure)
PSOD: Public Safety Observer Device (for brevity in this figure)
Editor-note-2: Stu: replace figure 4 Figure 4
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] and other external standards, IETF standards, complementing [F3411] and other external standards,
to satisfy UAS RID requirements. 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 presenting the gaps between the UAS RID architecture. This includes presenting the gaps between the
CAAs' Concepts of Operations and [F3411] as it relates to the use of CAAs' Concepts of Operations and [F3411] as it relates to the use of
Internet technologies and UA direct RF communications. Issues Internet technologies and UA direct RF communications. Issues
include, but are not limited to: include, but are not limited to:
o Design of trustworthy remote identifiers (Section 4). o Design of trustworthy remote identifiers (Section 3).
- Mechanisms to leverage Domain Name System (DNS [RFC1034]), - Mechanisms to leverage Domain Name System (DNS [RFC1034]),
Extensible Provisioning Protocol (EPP [RFC5731]) and Extensible Provisioning Protocol (EPP [RFC5731]) and
Registration Data Access Protocol (RDAP) ([RFC7482]) for Registration Data Access Protocol (RDAP) ([RFC7482]) for
publishing public and private information (see Section 5.1 and publishing public and private information (see Section 4.1 and
Section 5.2). Section 4.2).
- 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 claimed sender (Section 6) and that sender is in the the claimed sender (Section 5) and that sender is in the
claimed registry (Section 5 and Section 6). claimed registry (Section 4 and Section 5).
- Harvesting broadcast RID messages for UTM inclusion - Harvesting broadcast RID messages for UTM inclusion
(Section 7). (Section 6).
- Methods for instantly establishing secure communications - Methods for instantly establishing secure communications
between an Observer and the pilot of an observed UAS between an Observer and the pilot of an observed UAS
(Section 8). (Section 7).
- Privacy in RID messages (PII protection) (Section 11). - Privacy in RID messages (PII protection) (Section 10).
2. Terms and Definitions 2. Terms and Definitions
2.1. Architecture Terminology 2.1. Architecture Terminology
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 BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown above. capitals, as shown above.
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2.2. Abbreviations 2.2. Abbreviations
EdDSA: Edwards-Curve Digital Signature Algorithm EdDSA: Edwards-Curve Digital Signature Algorithm
HHIT: Hierarchical HIT HHIT: Hierarchical HIT
HIP: Host Identity Protocol HIP: Host Identity Protocol
HIT: Host Identity Tag HIT: Host Identity Tag
2.3. Additional Definitions 2.3. Claims, Assertions, Attestations, and Certificates
This document uses terms defined in [I-D.ietf-drip-reqs].
3. Claims, Assertions, Attestations, and Certificates
Editor-note-7: (Bob) move section 3 to Section 2.4?
This section introduces the terms "Claims", "Assertions", This section introduces the terms "Claims", "Assertions",
"Attestations", and "Certificates" as used in DRIP. DRIP certificate "Attestations", and "Certificates" as used in DRIP. DRIP certificate
has a different context compared with security certificates and has a different context compared with security certificates and
Public Key Infrastructure used in X.509. Public Key Infrastructure used in X.509.
Claims: Claims:
A claim in DRIP is a predicate (e.g., "X is Y", "X has property A claim in DRIP is a predicate (e.g., "X is Y", "X has property
Y", and most importantly "X owns Y" or "X is owned by Y"). Y", and most importantly "X owns Y" or "X is owned by Y").
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relationship with another entity, along with other information, relationship with another entity, along with other information,
and the asserting entity signs the assertion, thereby making it an and the asserting entity signs the assertion, thereby making it an
attestation. attestation.
Certificates: Certificates:
A certificate in DRIP is an attestation, strictly over identity A certificate in DRIP is an attestation, 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 attestation(s) its signing over. one with no stake in the attestation(s) its signing over.
4. HHIT as the DRIP Entity Identifier 2.4. Additional Definitions
This document uses terms defined in [I-D.ietf-drip-reqs].
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 external
technical standard ASTM [F3411] and regulatory constraints. It technical standard ASTM [F3411] 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) as self-asserting IPv6 addresses suitable as a UAS ID type (HHITs) as self-asserting IPv6 addresses suitable as a UAS ID type
and more generally as trustworthy multipurpose remote identifiers. and more generally as trustworthy multipurpose remote identifiers.
Self-asserting in this usage is given the Host Identity (HI), the Self-asserting in this usage is given the Host Identity (HI), the
HHIT ORCHID construction and a signature of the HHIT by the HI can HHIT ORCHID construction and a signature of the HHIT by the HI can
both be validated. The explicit registration hierarchy within the both be validated. The explicit registration hierarchy within the
HHIT provides registry discovery (managed by a Registrar) to either HHIT provides registry discovery (managed by a Registrar) to either
yield the HI for 3rd-party (who is looking for ID attestation) yield the HI for 3rd-party (who is looking for ID attestation)
validation or prove the HHIT and HI have uniquely been registered. validation or prove the HHIT and HI have uniquely been registered.
4.1. 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 [I-D.ietf-drip-reqs]). This Requirement GEN-1, ID-4 and ID-5 in [I-D.ietf-drip-reqs]). This
means that given a sufficient collection of RID messages, an Observer means that given a sufficient collection of RID messages, an Observer
can establish that the identifier claimed therein uniquely belongs to can establish that the identifier claimed therein uniquely belongs to
the claimant: that the only way for any other entity to prove the claimant: that the only way for any other entity to prove
ownership of that identifier would be to obtain information that ownership of that identifier would be to obtain information that
ought to be available only to the legitimate owner of the identifier ought to be available only to the legitimate owner of the identifier
(e.g., a cryptographic private key). (e.g., a cryptographic private key).
skipping to change at page 12, line 36 skipping to change at page 12, line 36
consumes one of those bytes to index the sub-type, leaving only 19 consumes one of those bytes to index the sub-type, leaving only 19
for the identifier (see DRIP Requirement ID-1). Likewise, the for the identifier (see DRIP Requirement ID-1). Likewise, the
maximum ASTM RID [F3411] Authentication Message payload is 201 bytes maximum ASTM RID [F3411] Authentication Message payload is 201 bytes
for most authentication types, but for type 5, also added in this for most authentication types, but for type 5, also added in this
revision, for IETF and other SDOs to develop Specific Authentication revision, for IETF and other SDOs to develop Specific Authentication
Methods as extensions to ASTM RID, one byte is consumed to index the Methods as extensions to ASTM RID, one byte is consumed to index the
sub-type, leaving only 200 for DRIP authentication payloads, sub-type, leaving only 200 for DRIP authentication payloads,
including one or more DRIP entity identifiers and associated including one or more DRIP entity identifiers and associated
authentication data. authentication data.
4.2. HHIT as A Trustworthy DRIP Entity Identifier 3.2. HHIT as A Trustworthy DRIP Entity Identifier
A Remote ID that can be trustworthily used in the RID Broadcast mode A Remote ID that can be trustworthily used in the RID Broadcast mode
can be built from an asymmetric keypair. Rather than using a key can be built from an asymmetric keypair. Rather than using a key
signing operation to claim ownership of an ID that does not guarantee signing operation to claim ownership of an ID that does not guarantee
name uniqueness, in this method the ID is cryptographically derived name uniqueness, in this method the ID is cryptographically derived
directly from the public key. The proof of ID ownership (verifiable directly from the public key. The proof of ID ownership (verifiable
attestation, versus mere claim) is guaranteed by signing this attestation, versus mere claim) is guaranteed by signing this
cryptographic ID with the associated private key. The association cryptographic ID with the associated private key. The association
between the ID and the private key is ensured by cryptographically between the ID and the private key is ensured by cryptographically
binding the public key with the ID, more specifically the ID results binding the public key with the ID, more specifically the ID results
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registration forces the attacker to generate the same public key registration forces the attacker to generate the same public key
rather than a public key that generates the same HHIT. This is in rather than a public key that generates the same HHIT. This is in
contrast to general IDs (e.g. a UUID or device serial number) as the contrast to general IDs (e.g. a UUID or device serial number) as the
subject in an X.509 certificate. subject in an X.509 certificate.
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 (more details in Section 10). possession of the manufacturer (more details in Section 9).
A UA equipped for Broadcast RID SHOULD be provisioned not only with A UA equipped for Broadcast RID SHOULD be provisioned not only with
its HHIT but also with the HI public key from which the HHIT was its HHIT but also with the HI public key from which the HHIT was
derived and the corresponding private key, to enable message derived and the corresponding private key, to enable message
signature. A UAS equipped for Network RID SHOULD be provisioned signature. A UAS equipped for Network RID SHOULD 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 (i.e. on the UA itself if the GCS is merely Network RID messages (i.e. on the UA itself if the GCS is merely
relaying rather than sourcing Network RID messages). Each Observer relaying rather than sourcing Network RID messages). Each Observer
device SHOULD be provisioned either with public keys of the DRIP device SHOULD be provisioned either with public keys of the DRIP
identifier root registries or certificates for subordinate identifier root registries or certificates for subordinate
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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 used with HIP to strongly mutually authenticate and
encrypt communications. encrypt communications.
A self-attestation of a HHIT used as a UAS ID can be done in as A self-attestation of a HHIT used as a UAS ID can be done in as
little as 84 bytes, by avoiding an explicit encoding technology like little as 84 bytes, by avoiding an explicit encoding technology like
ASN.1 or Concise Binary Object Representation (CBOR [RFC8949]). This ASN.1 or Concise Binary Object Representation (CBOR [RFC8949]). This
attestation consists of only the HHIT, a timestamp, and the EdDSA attestation consists of only the HHIT, a timestamp, and the EdDSA
signature on them. signature on them.
An Observer would need Internet access to validate a self- In general, Internet access may be needed to validate Attestations or
attestations claim. A third-party Certificate can be validated via a Certificates. This may be obviated in the most common cases (e.g.
small credential cache in a disconnected environment. This third- attestation of the UAS ID), even in disconnected environments, by
party Certificate is possible when the third-party also uses HHITs prepopulating small caches on Observer devices with Registry public
for its identity and the UA has the public key and the Certificate keys and a chain of Attestations or Certificates (tracing a path
for that HHIT. through the Registry tree). This is assuming all parties on the
trust path also use HHITs for their identities.
Editor-note-3: review the last/above pragraph.
4.3. HHIT for DRIP Identifier Registration and Lookup 3.3. HHIT for DRIP Identifier Registration and Lookup
Remote ID needs a deterministic lookup mechanism that rapidly Remote ID needs a deterministic lookup mechanism that rapidly
provides actionable information about the identified UA. Given the provides actionable information about the identified UA. Given the
size constraints imposed by the Bluetooth 4 broadcast media, the UAS size constraints imposed by the Bluetooth 4 broadcast media, the UAS
ID itself needs to be a non-spoofable inquiry input into the lookup. ID 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. This is HHIT provides manageable uniqueness of the HI for the HHIT. This is
the defense against a cryptographic hash second pre-image attack on the defense against a cryptographic hash second pre-image attack on
the HHIT (e.g. multiple HIs yielding the same HHIT, see Requirement the HHIT (e.g. multiple HIs yielding the same HHIT, see Requirement
ID-3). A lookup of the HHIT into this registration data provides the ID-3). A lookup of the HHIT into this registration data provides the
registered HI for HHIT proof. A first-come-first-serve registration registered HI for HHIT proof. A first-come-first-serve registration
for a HHIT provides deterministic access to any other needed for a HHIT provides 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 5.2). details in Section 4.2).
4.4. HHIT as a Cryptographic Identifier 3.4. HHIT as a Cryptographic Identifier
The only (known to the authors at the time of this writing) extant The only (known to the authors at the time of this writing) extant
types of IP address compatible identifiers cryptographically derived types of IP address compatible identifiers cryptographically derived
from the public keys of the identified entities are Cryptographically from 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 is registered and a cryptographic hash of that hierarchy within which is registered and a cryptographic hash of that
information concatenated with the entity's public key, etc. Although information concatenated with the entity's public key, etc. Although
hash collisions may occur, the registrar can detect them and reject hash collisions may occur, the registrar can detect them and reject
registration requests rather than issue credentials, e.g., by registration requests rather than issue credentials, e.g., by
enforcing a first-claimed, first-attested policy. Pre-image hash enforcing a first-claimed, first-attested policy. Pre-image hash
attacks are also mitigated through this registration process, locking attacks are also mitigated through this registration process, locking
the HHIT to a specific HI the HHIT to a specific HI
5. DRIP Identifier Registration and Registries 4. DRIP Identifier Registration and Registries
Editor-note-4: Section 5 needs to cite the corresponding numbered
requirement that it supports.
DRIP registries hold both public and private UAS information DRIP registries hold both public and private UAS information
resulting from the DRIP identifier registration process. Given these resulting from the DRIP identifier registration process. Given these
different uses, and to improve scalability, security, and simplicity different uses, and to improve scalability, security, and simplicity
of administration, the public and private information can be stored of administration, the public and private information can be stored
in different registries. This section introduces the public and in different registries. This section introduces the public and
private information registries for DRIP identifiers. private information registries for DRIP identifiers. This DRIP
Identifier registration process satisfies the following DRIP
requirements defined in [I-D.ietf-drip-reqs]: GEN-3, GEN-4, ID-2, ID-
4, ID-6, PRIV-3, PRIV-4, REG-1, PRG-2, REG-3 and REG-4.
5.1. Public Information Registry 4.1. Public Information Registry
5.1.1. Background 4.1.1. Background
The public registry provides trustable information such as The public registry provides trustable information such as
attestations of RID ownership and registration with the HDA attestations of RID ownership and registration with the HDA
(Hierarchical HIT Domain Authority). Optionally, pointers to the (Hierarchical HIT Domain Authority). Optionally, pointers to the
registries for the HDA and RAA (Registered Assigning registries for the HDA and RAA (Registered Assigning
Authority)implicit in the RID can be included (e.g., for HDA and RAA Authority)implicit in the RID can be included (e.g., for HDA and RAA
HHIT|HI used in attestation signing operations). This public HHIT|HI used in attestation signing operations). This public
information will be principally used by Observers of Broadcast RID information will be principally used by Observers of Broadcast RID
messages. Data on UAS that only use Network RID, is available via an messages. Data on UAS that only use Network RID, is available via an
Observer's Net-RID DP that would tend to directly provide all public Observer's Net-RID DP that would tend to directly provide all public
registry information. The Observer may visually "see" these Net-RID registry information. The Observer may visually "see" these Net-RID
UAS, but they may be silent to the Observer. The Net-RID DP is the UAS, but they may be silent to the Observer. The Net-RID DP is the
only source of information based on a query for an airspace volume. only source of information based on a query for an airspace volume.
5.1.2. DNS as the Public DRIP Identifier Registry 4.1.2. DNS as the Public DRIP Identifier Registry
A DRIP identifier SHOULD be registered as an Internet domain name (at A DRIP identifier SHOULD 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 DNS
can provide all the needed public DRIP information. A standardized can provide all the needed public DRIP information. A standardized
HHIT FQDN (Fully Qualified Domain Name) can deliver the HI via a HIP HHIT FQDN (Fully Qualified Domain Name) can deliver the HI via a HIP
RR (Resource Record) [RFC8005] and other public information (e.g., RR (Resource Record) [RFC8005] and other public information (e.g.,
RRA and HDA PTRs, and HIP RVS (Rendezvous Servers) [RFC8004]). These RRA and HDA PTRs, and HIP RVS (Rendezvous Servers) [RFC8004]). These
public information registries can use secure DNS transport (e.g. DNS public information registries can use secure DNS transport (e.g. DNS
over TLS) to deliver public information that is not inherently over TLS) to deliver public information that is not inherently
trustable (e.g. everything other than attestations). trustable (e.g. everything other than attestations).
5.2. Private Information Registry 4.2. Private Information Registry
5.2.1. 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:
registration protocols, infrastructure, and business models, by registration protocols, infrastructure, and business models, by
fitting into an ID structure compatible with DNS names. The HHIT fitting into an 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 registry function will be structure. It is expected that the private registry function will be
provided by the same organizations that run a USS, and likely provided by the same organizations that run a USS, and likely
integrated with a USS. The lookup function may be implemented by the integrated with a USS. The lookup function may be implemented by the
Net-RID DPs. Net-RID DPs.
5.2.2. EPP and RDAP as the Private DRIP Identifier Registry 4.2.2. EPP and RDAP as the Private DRIP Identifier Registry
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 open operations (e.g. add, delete, update, query) using interoperable open
standard protocols. It can accomplish this by using the Extensible standard protocols. It can accomplish this by using the Extensible
Provisioning Protocol (EPP [RFC5730]) and the Registry Data Access Provisioning Protocol (EPP [RFC5730]) and the Registry Data Access
Protocol (RDAP RFC7480] [RFC7482] [RFC7483]). The DRIP private Protocol (RDAP RFC7480] [RFC7482] [RFC7483]). The DRIP private
information registry in which a given UAS is registered needs to be information registry in which a given UAS is registered needs to be
findable, starting from the UAS ID, using the methods specified in findable, starting from the UAS ID, using the methods specified in
[RFC7484]. [RFC7484].
5.2.3. Alternative Private DRIP Registry methods 4.2.3. 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
deployed. These alternative methods may be used by Net-RID DP with deployed. These alternative methods may be used by Net-RID DP with
specific customers. specific customers.
6. DRIP Identifier Trust 5. DRIP Identifier Trust
Editor-note-5: Section 6 doesn't use the word "authentication" in the
section title, is there a reason to avoid it?
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" specified in [I-D.ietf-drip-reqs]. For provide the "trustworthiness" specified in [I-D.ietf-drip-reqs]. For
that it MUST be registered (under DRIP Registries) and be actively that it MUST be registered (under DRIP Registries) and be actively
used by the party (in most cases the UA). For Broadcast RID this is used by the party (in most cases the UA). For Broadcast RID this is
a challenge to balance the original requirements of Broadcast RID and a challenge to balance the original requirements of Broadcast RID and
the efforts needed to satisfy the DRIP requirements all under severe the efforts needed to satisfy the DRIP requirements all under severe
constraints. constraints.
From received Broadcast RID messages and information that can be
looked up using the received UAS ID in online registries or local
caches, it is possible to establish levels of trust in the asserted
information and the Operator.
An optimization of different DRIP Authentication Messages allows an An optimization of different DRIP Authentication Messages allows an
Observer, without Internet connection (offline) or with (online), to Observer, without Internet connection (offline) or with (online), to
be able to validate a UAS DRIP ID in real-time. First is the sending be able to validate a UAS DRIP ID in real-time. First is the sending
of Broadcast Attestations (over DRIP Link Authentication Messages) of Broadcast Attestations (over DRIP Link Authentication Messages)
containing the relevant registration of the UA's DRIP ID in the containing the relevant registration of the UA's DRIP ID in the
claimed Registry. Next is sending DRIP Wrapper Authentication claimed Registry. Next is sending DRIP Wrapper Authentication
Messages that sign over both static (e.g. above registration) and Messages that sign over both static (e.g. above registration) and
dynamically changing data (such as UA location data). Combining dynamically changing data (such as UA location data). Combining
these two sets of information an Observer can piece together a chain these two sets of information an Observer can piece together a chain
of trust and real-time evidence to make their determination of the of trust and real-time evidence to make their determination of the
UAs claims. UAs 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 requirement defined in [I-D.ietf-drip-reqs]: GEN-1, GEN-2, GEN- DRIP requirement defined in [I-D.ietf-drip-reqs]: GEN-1, GEN-2, GEN-
3, ID-2, ID-3, ID-4 and ID-5. 3, ID-2, ID-3, ID-4 and ID-5.
7. Harvesting Broadcast Remote ID messages for UTM Inclusion 6. Harvesting Broadcast Remote ID messages for UTM Inclusion
Editor-note-6: Section 7 needs to cite the corresponding numbered
requirement that it supports.
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 RID requirements for small UAS Network RID for large UAS, but allow RID requirements for small UAS
to be satisfied with the operator's choice of either Broadcast RID or to be satisfied with the operator's choice of either Broadcast RID or
Network RID. The EASA initially specified Broadcast RID for UAS of Network RID. The EASA initially specified Broadcast RID for UAS of
essentially all UAS and is now also considering Network RID. The FAA essentially all UAS and is now also considering Network RID. The FAA
RID Final Rules [FAA_RID] permit only Broadcast RID for rule 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.
skipping to change at page 18, line 5 skipping to change at page 17, line 49
subject not only to natural time lag and error but also operator subject not only to natural time lag and error but also operator
misconfiguration or intentional deception. misconfiguration or intentional deception.
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 RID messages. This confirming or refuting those claims made in the RID messages. This
Crowd Sourced Remote ID (CS-RID) would be a significant enhancement, Crowd Sourced Remote ID (CS-RID) would be a significant enhancement,
beyond baseline DRIP functionality; if implemented, it adds two more beyond baseline DRIP functionality; if implemented, it adds two more
entity types. entity types.
7.1. The CS-RID Finder This approach satisfies the following DRIP requirements defined in
[I-D.ietf-drip-reqs]: GEN-5, GEN-11, and REG-1.
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
the UTM. It performs this gateway function via a CS-RID SDSP. A CS- the UTM. It performs this gateway function via a CS-RID SDSP. A CS-
RID Finder could implement, integrate, or accept outputs from, a RID Finder could implement, integrate, or accept outputs from, a
Broadcast RID receiver. However, it should not depend upon a direct Broadcast RID receiver. However, it should not depend upon a direct
interface with a GCS, Net-RID SP, Net-RID DP or Network RID client. interface with a GCS, Net-RID SP, Net-RID DP or Network RID client.
It would present a TBD interface to a CS-RID SDSP, similar to but It would present a TBD interface to a CS-RID SDSP, similar to but
readily distinguishable from that between a GCS and a Net-RID SP. readily distinguishable from that between a GCS and a Net-RID SP.
7.2. 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 location
using including using multilateration when possible) information using including using multilateration when possible) information
collected by CS-RID Finders. A CS-RID SDSP should appear (i.e. collected by CS-RID Finders. A CS-RID SDSP should appear (i.e.
present the same interface) to a Net-RID SP as a Net-RID DP. present the same interface) to a Net-RID SP as a Net-RID DP.
Editor-note-8: double check above paragraph after Editor-note-1 is 7. DRIP Contact
resolved.
8. DRIP Contact
One of the ways in which DRIP can enhance [F3411] with immediately One of the ways in which DRIP can enhance [F3411] with immediately
actionable information is by enabling an Observer to instantly actionable information is by enabling an Observer to instantly
initiate secure communications with the UAS remote pilot, Pilot In initiate secure communications with the UAS remote pilot, Pilot In
Command, operator, USS under which the operation is being flown, or Command, operator, USS under which the operation is being flown, or
other entity potentially able to furnish further information other entity potentially able to furnish further information
regarding the operation and its intent and/or to immediately regarding the operation and its intent and/or to immediately
influence further conduct or termination of the operation (e.g., land influence further conduct or termination of the operation (e.g., land
or otherwise exit an airspace volume). Such potentially distracting or otherwise exit an airspace volume). Such potentially distracting
communications demand strong "AAA" (Authentication, Attestation, communications demand strong "AAA" (Authentication, Attestation,
Authorization, Access Control, Accounting, Attribution, Audit) per Authorization, Access Control, Accounting, Attribution, Audit) per
applicable policies (e.g., of the cognizant CAA). applicable policies (e.g., of the cognizant CAA).
A DRIP entity identifier based on a HHIT as outlined in Section 4 A DRIP entity identifier based on a HHIT as outlined in Section 3
embeds an identifier of the registry in which it can be found embeds an identifier of the registry in which it can be found
(expected typically to be the USS under which the UAS is flying) and (expected typically to be the USS under which the UAS is flying) and
the procedures outlined in Section 6 enable Observer verification of the procedures outlined in Section 5 enable Observer verification of
that relationship. A DRIP entity identifier with suitable records in that 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). An Observer equipped with HIP can locators, typically IP addresses). An Observer equipped with HIP can
initiate a Base Exchange (BEX) and establish a Bound End to End initiate a Base Exchange (BEX) and establish a Bound End to End
Tunnel (BEET) protected by IPsec Encapsulating Security Payload (ESP) Tunnel (BEET) protected by IPsec Encapsulating Security Payload (ESP)
encryption to a likewise equipped and identified entity: the UA encryption to a likewise equipped and identified entity: the UA
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currently usable locator (IP address); and there must be currently currently usable locator (IP address); and there must be currently
usable bidirectional IP (not necessarily Internet) connectivity usable bidirectional IP (not necessarily Internet) connectivity
between the parties. Given a BEET, arbitrary standard higher layer between the parties. Given a BEET, arbitrary standard higher layer
protocols can then be used for Observer to Pilot (O2P) communications protocols can then be used for Observer to Pilot (O2P) communications
(e.g., SIP [RFC3261] et seq), V2X communications (e.g., [MAVLink]), (e.g., SIP [RFC3261] et seq), V2X communications (e.g., [MAVLink]),
etc. This approach satisfies DRIP requirement GEN-6 Contact, etc. This approach satisfies DRIP requirement GEN-6 Contact,
supports satisfaction of requirements [I-D.ietf-drip-reqs] GEN-8, supports satisfaction of requirements [I-D.ietf-drip-reqs] GEN-8,
GEN-9, PRIV-2, PRIV-5 and REG-3, and is compatible with all other GEN-9, PRIV-2, PRIV-5 and REG-3, and is compatible with all other
DRIP requirements. DRIP requirements.
9. IANA Considerations 8. IANA Considerations
This document does not make any IANA request. This document does not make any IANA request.
10. Security Considerations 9. Security Considerations
The security provided by asymmetric cryptographic techniques depends The security provided by asymmetric cryptographic techniques depends
upon protection of the private keys. A manufacturer that embeds a upon protection of the private keys. A manufacturer that embeds a
private key in an UA may have retained a copy. A manufacturer whose private key in an UA may have retained a copy. A manufacturer whose
UA are configured by a closed source application on the GCS which UA are configured by a closed source application on the GCS which
communicates over the Internet with the factory may be sending a copy communicates over the Internet with the factory may be sending a copy
of a UA or GCS self-generated key back to the factory. Keys may be of a UA or GCS self-generated key back to the factory. Keys may be
extracted from a GCS or UA. The RID sender of a small harmless UA extracted from a GCS or UA. The RID sender of a small harmless UA
(or the entire UA) could be carried by a larger dangerous UA as a (or the entire UA) could be carried by a larger dangerous UA as a
"false flag." Compromise of a registry private key could do "false flag." Compromise of a registry private key could do
widespread harm. Key revocation procedures are as yet to be widespread harm. Key revocation procedures are as yet to be
determined. These risks are in addition to those involving Operator determined. These risks are in addition to those involving Operator
key management practices. key management practices.
11. Privacy & Transparency Considerations 10. Privacy & Transparency Considerations
Broadcast RID messages can contain Personally Identifiable Broadcast RID messages can contain Personally Identifiable
Information (PII). A viable architecture for PII protection would be Information (PII). A viable architecture for PII protection would be
symmetric encryption of the PII using a session key known to the UAS symmetric encryption of the PII using a session key known to the UAS
and its USS. Authorized Observers could obtain plaintext in either and its USS. Authorized Observers could obtain plaintext in either
of two ways. An Observer can send the UAS ID and the cyphertext to a of two ways. An Observer can send the UAS ID and the cyphertext to a
server that offers decryption as a service. An Observer can send the server that offers decryption as a service. An Observer can send the
UAS ID only to a server that returns the session key, so that UAS ID only to a server that returns the session key, so that
Observer can directly locally decrypt all cyphertext sent by that UA Observer can directly locally decrypt all cyphertext sent by that UA
during that session (UAS operation). In either case, the server can during that session (UAS operation). In either case, the server can
be: a Public Safety USS; the Observer's own USS; or the UA's USS if be: a Public Safety USS; the Observer's own USS; or the UA's USS if
the latter can be determined (which under DRIP it can be, from the the latter can be determined (which under DRIP it can be, from the
UAS ID itself). PII can be protected unless the UAS is informed UAS ID itself). PII can be protected unless the UAS is informed
otherwise. This could come as part of UTM operation authorization. otherwise. This could come as part of UTM operation authorization.
It can be special instructions at the start or during an operation. It can be special instructions at the start or during an operation.
PII protection MUST not be used if the UAS loses connectivity to the PII protection MUST not be used if the UAS loses connectivity to the
USS. The UAS always has the option to abort the operation if PII USS. The UAS always has the option to abort the operation if PII
protection is disallowed. protection is disallowed.
12. References 11. References
12.1. Normative References 11.1. Normative References
[I-D.ietf-drip-reqs] [I-D.ietf-drip-reqs]
Card, S. W., Wiethuechter, A., Moskowitz, R., and A. Card, S. W., Wiethuechter, A., Moskowitz, R., and A.
Gurtov, "Drone Remote Identification Protocol (DRIP) Gurtov, "Drone Remote Identification Protocol (DRIP)
Requirements", Work in Progress, Internet-Draft, draft- Requirements", Work in Progress, Internet-Draft, draft-
ietf-drip-reqs-18, 8 September 2021, ietf-drip-reqs-18, 8 September 2021,
<https://www.ietf.org/archive/id/draft-ietf-drip-reqs- <https://www.ietf.org/archive/id/draft-ietf-drip-reqs-
18.txt>. 18.txt>.
[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>.
12.2. Informative References 11.2. Informative References
[CTA2063A] ANSI, "Small Unmanned Aerial Systems Serial Numbers", [CTA2063A] ANSI, "Small Unmanned Aerial Systems Serial Numbers",
2019. 2019.
[Delegated] [Delegated]
European Union Aviation Safety Agency (EASA), "EU European Union Aviation Safety Agency (EASA), "EU
Commission Delegated Regulation 2019/945 of 12 March 2019 Commission Delegated Regulation 2019/945 of 12 March 2019
on unmanned aircraft systems and on third-country on unmanned aircraft systems and on third-country
operators of unmanned aircraft systems", 2019. operators of unmanned aircraft systems", 2019.
skipping to change at page 21, line 12 skipping to change at page 21, line 12
<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)", 2020,
<https://www.faa.gov/uas/research_development/ <https://www.faa.gov/uas/research_development/
traffic_management/media/UTM_ConOps_v2.pdf>. traffic_management/media/UTM_ConOps_v2.pdf>.
[FS_AEUA] "Study of Further Architecture Enhancement for UAV and
UAM", 2021, <https://www.3gpp.org/ftp/tsg_sa/WG2_Arch/
TSGS2_147E_Electronic_2021-10/Docs/S2-2107092.zip>.
[Implementing] [Implementing]
European Union Aviation Safety Agency (EASA), "EU European Union Aviation Safety Agency (EASA), "EU
Commission Implementing Regulation 2019/947 of 24 May 2019 Commission Implementing Regulation 2019/947 of 24 May 2019
on the rules and procedures for the operation of unmanned on the rules and procedures for the operation of unmanned
aircraft", 2019. aircraft", 2019.
[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", n.d.,
<https://www.faa.gov/uas/programs_partnerships/ <https://www.faa.gov/uas/programs_partnerships/
data_exchange/>. data_exchange/>.
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