draft-ietf-drip-arch-13.txt   draft-ietf-drip-arch-14.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: 28 November 2021 R. Moskowitz Expires: 10 January 2022 R. Moskowitz
HTT Consulting HTT Consulting
S. Zhao (Editor) S. Zhao (Editor)
Tencent Tencent
A. Gurtov A. Gurtov
Linköping University Linköping University
27 May 2021 9 July 2021
Drone Remote Identification Protocol (DRIP) Architecture Drone Remote Identification Protocol (DRIP) Architecture
draft-ietf-drip-arch-13 draft-ietf-drip-arch-14
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
satisfies 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
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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
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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
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This Internet-Draft will expire on 28 November 2021. This Internet-Draft will expire on 10 January 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
skipping to change at page 2, line 24 skipping to change at page 2, line 24
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 . . . . . . . . . . . . 6 1.3. Overview of USS Interoperability . . . . . . . . . . . . 6
1.4. Overview of DRIP Architecture . . . . . . . . . . . . . . 7 1.4. Overview of DRIP Architecture . . . . . . . . . . . . . . 7
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 9 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 9
3. Definitions and Abbreviations . . . . . . . . . . . . . . . . 9 3. Definitions and Abbreviations . . . . . . . . . . . . . . . . 9
3.1. Additional Definitions . . . . . . . . . . . . . . . . . 9 3.1. Additional Definitions . . . . . . . . . . . . . . . . . 9
3.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 9 3.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 9
3.3. Claims, Assertions, Attestations, and Certificates . . . 10 3.3. Claims, Assertions, Attestations, and Certificates . . . 10
4. HHIT for DRIP Entity Identifier . . . . . . . . . . . . . . . 11 4. HHIT as the Primary DRIP Entity Identifier . . . . . . . . . 11
4.1. UAS Remote Identifiers Problem Space . . . . . . . . . . 11 4.1. UAS Remote Identifiers Problem Space . . . . . . . . . . 11
4.2. HIT as A Trustworthy DRIP Entity Identifier . . . . . . . 12 4.2. HIT as A Trustworthy DRIP Entity Identifier . . . . . . . 12
4.3. HHIT for DRIP Identifier Registration and Lookup . . . . 13 4.3. HHIT for DRIP Identifier Registration and Lookup . . . . 14
4.4. HHIT for DRIP Identifier Cryptographic . . . . . . . . . 14 4.4. HHIT for DRIP Identifier Cryptographic . . . . . . . . . 14
5. DRIP Identifier Registration and Registries . . . . . . . . . 14 5. DRIP Identifier Registration and Registries . . . . . . . . . 14
5.1. Public Information Registry . . . . . . . . . . . . . . . 14 5.1. Public Information Registry . . . . . . . . . . . . . . . 15
5.1.1. Background . . . . . . . . . . . . . . . . . . . . . 14 5.1.1. Background . . . . . . . . . . . . . . . . . . . . . 15
5.1.2. Proposed Approach . . . . . . . . . . . . . . . . . . 14 5.1.2. Proposed Approach . . . . . . . . . . . . . . . . . . 15
5.2. Private Information Registry . . . . . . . . . . . . . . 15 5.2. Private Information Registry . . . . . . . . . . . . . . 15
5.2.1. Background . . . . . . . . . . . . . . . . . . . . . 15 5.2.1. Background . . . . . . . . . . . . . . . . . . . . . 15
5.2.2. Proposed Approach . . . . . . . . . . . . . . . . . . 15 5.2.2. Proposed Approach . . . . . . . . . . . . . . . . . . 16
6. Harvesting Broadcast Remote ID messages for UTM Inclusion . . 15 6. Harvesting Broadcast Remote ID messages for UTM Inclusion . . 16
6.1. The CS-RID Finder . . . . . . . . . . . . . . . . . . . . 16 6.1. The CS-RID Finder . . . . . . . . . . . . . . . . . . . . 17
6.2. The CS-RID SDSP . . . . . . . . . . . . . . . . . . . . . 16 6.2. The CS-RID SDSP . . . . . . . . . . . . . . . . . . . . . 17
7. Privacy for Broadcast PII . . . . . . . . . . . . . . . . . . 16 7. IANA Consideration . . . . . . . . . . . . . . . . . . . . . 17
8. Security Considerations . . . . . . . . . . . . . . . . . . . 17 8. Security Considerations . . . . . . . . . . . . . . . . . . . 17
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17 9. Privacy & Transparency Considerations . . . . . . . . . . . . 18
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 17 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
10.1. Normative References . . . . . . . . . . . . . . . . . . 17 10.1. Normative References . . . . . . . . . . . . . . . . . . 18
10.2. Informative References . . . . . . . . . . . . . . . . . 18 10.2. Informative References . . . . . . . . . . . . . . . . . 18
Appendix A. Overview of Unmanned Aircraft Systems (UAS) Traffic Appendix A. Overview of Unmanned Aircraft Systems (UAS) Traffic
Management (UTM) . . . . . . . . . . . . . . . . . . . . 20 Management (UTM) . . . . . . . . . . . . . . . . . . . . 21
A.1. Operation Concept . . . . . . . . . . . . . . . . . . . . 21 A.1. Operation Concept . . . . . . . . . . . . . . . . . . . . 21
A.2. UAS Service Supplier (USS) . . . . . . . . . . . . . . . 21 A.2. UAS Service Supplier (USS) . . . . . . . . . . . . . . . 22
A.3. UTM Use Cases for UAS Operations . . . . . . . . . . . . 22 A.3. UTM Use Cases for UAS Operations . . . . . . . . . . . . 22
A.4. Automatic Dependent Surveillance Broadcast (ADS-B) . . . 22 Appendix B. Automatic Dependent Surveillance Broadcast
(ADS-B) . . . . . . . . . . . . . . . . . . . . . . . . . 23
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
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 Remote Identification and tracking support Unmanned Aircraft System Remote Identification and tracking
(UAS RID), plus RID-related communications. The architecture takes (UAS RID), plus RID-related communications. The architecture takes
into account both current (including proposed) regulations and non- into account both current (including proposed) regulations and non-
IETF technical standards. 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 [I-D.ietf-drip-reqs]. Requirements document [I-D.ietf-drip-reqs].
1.1. Overview of Unmanned Aircraft System (UAS) Remote ID (RID) and 1.1. Overview of Unmanned Aircraft System (UAS) Remote ID (RID) and
Standardization Standardization
CAAs currently promulgate performance-based regulations that do not
specify techniques, but rather cite industry consensus technical
standards as acceptable means of compliance.
UAS Remote Identification (RID) is an application enabler for a UAS UAS Remote Identification (RID) is an application enabler for a UAS
to be identified by Unmanned Aircraft Systems Traffic Management to be identified by Unmanned Aircraft Systems Traffic Management
(UTM) and UAS Service Supplier (USS) (Appendix A) or third parties (UTM) and UAS Service Supplier (USS) (Appendix A) or third parties
entities such as law enforcement. Many considerations (e.g., safety) entities such as law enforcement. Many considerations (e.g., safety)
dictate that UAS be remotely identifiable. Civil Aviation dictate that UAS be remotely identifiable. Civil Aviation
Authorities (CAAs) worldwide are mandating UAS RID. For example, the Authorities (CAAs) worldwide are mandating UAS RID. For example, the
European Union Aviation Safety Agency (EASA) has published European Union Aviation Safety Agency (EASA) has published
[Delegated] and [Implementing] Regulations. [Delegated] and [Implementing] Regulations.
CAAs currently promulgate performance-based regulations that do not
specify techniques, but rather cite industry consensus technical
standards as acceptable means of compliance.
Federal Aviation Administration (FAA) 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 whereafter published the "Final Rule" in 2021 [FAA_RID]. In and whereafter published the "Final Rule" in 2021 [FAA_RID]. In
FAA's final rule, it is clearly stated that Automatic Dependent FAA's final rule, it is clearly stated that Automatic Dependent
Surveillance Broadcast (ADS-B) Out and transponders can not be Surveillance Broadcast (ADS-B) Out and transponders can not be
used to serve the purpose of an remote identification. More used to serve the purpose of an remote identification. More
details about ADS-B can be found in Appendix A.4. details about ADS-B can be found in Appendix B.
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 the
ASTM [F3411-19] Standard Specification for Remote ID and Tracking. ASTM [F3411-19] Standard Specification for Remote ID and Tracking.
ASTM defines one set of RID information and two means, MAC-layer ASTM defines one set of RID information and two means, MAC-layer
broadcast and IP-layer network, of communicating it. If an UAS broadcast and IP-layer network, of communicating it. If an UAS
uses both communication methods, the same information must be uses both communication methods, the same information must be
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final rule [FAA_RID] as "a potential means of compliance" to a final rule [FAA_RID] as "a potential means of compliance" to a
Remote ID rule. Remote ID 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 network. will be applicable for both 4G and 5G networks.
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
A set of RID messages are defined for direct, one-way, broadcast A set of RID messages are defined 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 locally directly received information lookup by Observers using the directly received UAS ID.
UAS RID as a key. Broadcast RID should be functionally usable in Broadcast RID should be functionally usable in situations with no
situations with no Internet connectivity. Internet connectivity.
The Broadcast RID is illustrated in Figure 1. The minimum Broadcast RID data flow is illustrated in Figure 1.
x x UA x x UA
xxxxx xxxxx
| |
| |
| app messages directly over | app messages directly over
| one-way RF data link (no IP) | one-way RF data link (no IP)
| |
| |
+ +
x x
xxxxx xxxxx
x x
x x
x x Observer's device (e.g. smartphone) x x Observer's device (e.g. smartphone)
x x x x
Figure 1 Figure 1
With Broadcast RID, an Observer is limited to their radio "visible" With queries sent over the Internet using harvested RID (see
airspace for UAS awareness and information. With queries sent over Section 6), the Observer may gain more information about those
the Internet using harvested RID (see Section 6), the Observer may visible UAS" is only true if the locally observed UAS is (or very
gain more information about those visible UAS. recently was) observed somewhere else; harvesting RID is not so much
about learning more about directly observed nearby UAS as it is about
surveillance of areas too large for local direct visual observation &
direct RF link based ID (e.g., an entire air force base, or even
larger, a national forest)
1.2.2. Network RID 1.2.2. Network RID
A RID data dictionary and data flow for Network RID are defined in A RID data dictionary and data flow for Network RID are defined in
[F3411-19]. This data flow is emitted from an UAS via unspecified [F3411-19]. This data flow is emitted from an UAS via unspecified
means (but at least in part over the Internet) to a Network Remote ID means (but at least in part over the Internet) to a Network Remote ID
Service Provider (Net-RID SP). A Net-RID SP provides the RID data to Service Provider (Net-RID SP). A Net-RID SP provides the RID data to
Network Remote ID Display Providers (Net-RID DP). It is the Net-RID Network Remote ID Display Providers (Net-RID DP). It is the Net-RID
DP that responds to queries from Network Remote ID Observers DP that responds to queries from Network Remote ID Observers
(expected typically, but not specified exclusively, to be web-based) (expected typically, but not specified exclusively, to be web-based)
specifying airspace volumes of interest. Network RID depends upon specifying airspace volumes of interest. Network RID depends upon
connectivity, in several segments, via the Internet, from the UAS to connectivity, in several segments, via the Internet, from the UAS to
the Observer. the Observer.
The Network RID is illustrated in Figure 2: Editor-note 1: + list all the segments mentioned above + specify
how DRIP provide solutions for each segment
The mimunum Network RID data flow is illustrated in Figure 2:
x x UA x x UA
xxxxx ******************** xxxxx ********************
| \ * ------*---+------------+ | \ * ------*---+------------+
| \ * / * | NET_RID_SP | | \ * / * | NET_RID_SP |
| \ * ------------/ +---*--+------------+ | \ * ------------/ +---*--+------------+
| RF \ */ | * | RF \ */ | *
| * INTERNET | * +------------+ | * INTERNET | * +------------+
| /* +---*--| NET_RID_DP | | /* +---*--| NET_RID_DP |
| / * +---*--+------------+ | / * +---*--+------------+
skipping to change at page 5, line 41 skipping to change at page 5, line 49
xxxxx | xxxxx xxxxx | xxxxx
x +------- x x +------- x
x x x x
x x Operator (GCS) Observer x x x x Operator (GCS) Observer x x
x x x x x x x x
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 BVLOS operations expected often to be wireless links with increasing beyond Visual Line of Sight (BVLOS) operations
at either end with the Internet between. For all, but the simplest expected often to be wireless links at either end with the Internet
hobby aircraft, telemetry (at least position and heading) flows from between.
the UA to the GCS via some path, typically the reverse of the C2
path. Thus, RID information pertaining to both the GCS and the UA Editor-note 2: Explain the difference with wireless and RF link
can be sent, by whichever has Internet connectivity, to the Net-RID includes what are the end entities, usages for each transport
SP, typically the USS managing the UAS operation. media.
For all but the simplest hobby aircraft, telemetry (at least position
and heading) flows from the UA to the GCS via some path, typically
the reverse of the C2 path. Thus, RID information pertaining to both
the GCS and the UA can be sent, by whichever has Internet
connectivity, to the Net-RID SP, typically the USS managing the UAS
operation.
Editor-note 3: Does all UAS support telemetry? explain what are
simplsest hobby aircraft vs UAS in general. Is it necessary to
keep "For all but the simplest hobby aircraft"?
The Net-RID SP forwards RID information via the Internet to The Net-RID SP forwards RID information via the Internet to
subscribed Net-RID DP, typically a USS. Subscribed Net-RID DP subscribed Net-RID DP, typically USS. Subscribed Net-RID DP forward
forward RID information via the Internet to subscribed Observer RID information via the Internet to subscribed Observer devices.
devices. Regulations require and [F3411-19] describes RID data Regulations require and [F3411-19] describes RID data elements that
elements that must be transported end-to-end from the UAS to the must be transported end-to-end from the UAS to the subscribed
subscribed Observer devices. Observer devices.
[F3411-19] prescribes the protocols only between the Net-RID SP, Net- [F3411-19] prescribes the protocols only between the Net-RID SP, Net-
RID DP, and the Discovery and Synchronization Service (DSS). DRIP RID DP, and the Discovery and Synchronization Service (DSS). DRIP
may also address standardization of protocols between the UA and GCS, may also address standardization of protocols between the UA and GCS,
between the UAS and the Net-RID SP, and/or between the Net-RID DP and between the UAS and the Net-RID SP, and/or between the Net-RID DP and
Observer devices. Observer devices.
Editor-note 4: "DRIP may also..." Specify what protocol DRIP can
or will standardize.
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 [F3411-19] Network RID. in the scope of [F3411-19] Network RID.
1.3. Overview of USS Interoperability 1.3. Overview of USS Interoperability
Each UAS is registered to at least one USS. With Net-RID, there is With Net-RID, there is direct communication between the UAS and its
direct communication between the UAS and its USS. With Broadcast- USS. With Broadcast-RID, the UAS Operator has either pre-filed a 4D
RID, the UAS Operator has either pre-filed a 4D space volume for USS space volume for USS operational knowledge and/or Observers can be
operational knowledge and/or Observers can be providing information providing information about observed UA to a USS. USS exchange
about observed UA to a USS. USS exchange information via a Discovery information via a Discovery and Synchronization Service (DSS) so all
and Synchronization Service (DSS) so all USS collectively have USS collectively have knowledge about all activities in a 4D
knowledge about all activities in a 4D airspace. airspace.
The interactions among Observer, UA, and USS are shown in Figure 3. The interactions among Observer, UA, and USS are shown in Figure 3.
+----------+ +----------+
| Observer | | Observer |
+----------+ +----------+
/ \ / \
/ \ / \
+-----+ +-----+ +-----+ +-----+
| UA1 | | UA2 | | UAS1 | | UAS2 |
+-----+ +-----+ +-----+ +-----+
\ / \ /
\ / \ /
+----------+ +----------+
| Internet | | Internet |
+----------+ +----------+
/ \ / \
/ \ / \
+-------+ +-------+ +-------+ +-------+
| USS-1 | <-------> | USS-2 | | USS1 | <-------> | USS2 |
+-------+ +-------+ +-------+ +-------+
\ / \ /
\ / \ /
+------+ +------+
| DSS | | DSS |
+------+ +------+
Figure 3 Figure 3
1.4. Overview of DRIP Architecture 1.4. Overview of DRIP Architecture
skipping to change at page 8, line 41 skipping to change at page 8, line 41
+----------+ +-----+ +----------+ +----------+ +-----+ +----------+
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 [F3411-19] and other external IETF standards, complementing [F3411-19] and other external
standards, to satisfy UAS RID requirements. standards, to satisfy UAS RID requirements.
This document outlines the UAS RID architecture into which DRIP must This document outlines the UAS RID architecture. This includes
fit and the architecture for DRIP itself. This includes presenting presenting the gaps between the CAAs' Concepts of Operations and
the gaps between the CAAs' Concepts of Operations and [F3411-19] as [F3411-19] as it relates to the use of Internet technologies and UA
it relates to the use of Internet technologies and UA direct RF direct RF communications. Issues include, but are not limited to:
communications. Issues include, but are not limited to:
- Design of trustworthy remote ID and trust in RID messages - Design of trustworthy remote ID and trust in RID messages
(Section 4) (Section 4)
- Mechanisms to leverage Domain Name System (DNS: [RFC1034]), - Mechanisms to leverage Domain Name System (including DNS:
Extensible Provisioning Protocol (EPP [RFC5731]) and [RFC1034]), Extensible Provisioning Protocol (EPP [RFC5731])
Registration Data Access Protocol (RDAP) ([RFC7482]) to provide and Registration Data Access Protocol (RDAP) ([RFC7482]) for
for private (Section 5.2) and public (Section 5.1) information publishing public and private information (see Section 5.1 and
registry. Section 5.2).
- Harvesting broadcast RID messages for UTM inclusion - Harvesting broadcast RID messages for UTM inclusion
(Section 6). (Section 6).
- Privacy in RID messages (PII protection) (Section 7). - Privacy in RID messages (PII protection) (Section 9).
2. Conventions 2. Conventions
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.
3. Definitions and Abbreviations 3. Definitions and Abbreviations
Editor-note 13: 1) should we merge Section 2 and Section 3 2) how
should we list abbr in the Arch? Previous WG agreement is that
all the DRIP terms shall be defined in -reqs, which may or may not
be used in -reqs itself, but other documents such as Arch-. And
arch- can list terms when they are used in the arch- only. So
which is which ?
3.1. Additional Definitions 3.1. Additional Definitions
This document uses terms defined in [I-D.ietf-drip-reqs]. This document uses terms defined in [I-D.ietf-drip-reqs].
3.2. Abbreviations 3.2. Abbreviations
ADS-B: Automatic Dependent Surveillance Broadcast ADS-B: Automatic Dependent Surveillance Broadcast
DSS: Discovery & Synchronization Service DSS: Discovery & Synchronization Service
skipping to change at page 10, line 19 skipping to change at page 10, line 27
UAS: Unmanned Aircraft System UAS: Unmanned Aircraft System
USS: UAS Service Supplier USS: UAS Service Supplier
UTM: UAS Traffic Management UTM: UAS Traffic Management
3.3. Claims, Assertions, Attestations, and Certificates 3.3. Claims, Assertions, Attestations, and Certificates
This section introduces the terms "Claims", "Assertions", This section introduces the terms "Claims", "Assertions",
"Attestations", and "Certificates" as used in DRIP. "Attestations", and "Certificates" as used in DRIP. DRIP certificate
has a different context compared with security certificates and
Public Key Infrastructure used in X.509.
This is due to the term "certificate" having significant Editor-note 5: To be confirmed
technological and legal baggage associated with it, specifically
around X.509 certificates. These types of certificates and Public
Key Infrastructure invoke more legal and public policy considerations
than probably any other electronic communication sector. It emerged
as a governmental platform for trusted identity management and was
pursued in intergovernmental bodies with links into treaty
instruments.
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").
Assertions: Assertions:
An assertion in DRIP is a set of claims. This definition is An assertion in DRIP is a set of claims. This definition is
borrowed from JWT [RFC7519] and CWT [RFC8392]. borrowed from JWT [RFC7519] and CWT [RFC8392].
skipping to change at page 11, line 5 skipping to change at page 11, line 8
claimant or a third party. Under DRIP this is normally used when claimant or a third party. Under DRIP this is normally used when
an entity asserts a relationship with another entity, along with an entity asserts a relationship with another entity, along with
other information, and the asserting entity signs the assertion, other information, and the asserting entity signs the assertion,
thereby making it an attestation. thereby making it an 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. information, signed by a third party.
4. HHIT for DRIP Entity Identifier 4. HHIT as the Primary DRIP Entity Identifier
This section describes the basic requirements of a DRIP entity This section describes the DRIP architectural approach to meeting the
identifier per regulation constrains from ASTM [F3411-19] and basic requirements of a DRIP entity identifier within external
explains the use of Hierarchical Host Identity Tags (HHITs) as self- technical standard ASTM [F3411-19] and regulatory constraints. It
asserting IPv6 addresses and thereby a trustable DRIP identifier for justifies and explains the use of Hierarchical Host Identity Tags
use as the UAS Remote ID. HHITs self-attest to the included explicit (HHITs) as self-asserting IPv6 addresses suitable as a UAS ID type
hierarchy that provides Registrar discovery for 3rd-party ID and more generally as trustworthy multipurpose remote identifiers.
attestation.
A HHIT, together with the Host Identity (HI) from which it is partly
derived, self-attests to its included explicit registration
hierarchy, providing Registrar discovery for a 3rd-party who is
looking for ID attestation retrieves the necessary information to the
registrar via a DNS request HHIT.
Editor-note 6: Is there a need to specify how self-attest works?
if yes then where? possible a new section under Section 4}
4.1. UAS Remote Identifiers Problem Space 4.1. UAS Remote Identifiers Problem Space
Editor-note 14: Good to have: adding match requirment numbering
from requirement document
A DRIP entity identifier needs to be "Trustworthy". This means that A DRIP entity identifier needs to be "Trustworthy". This means that
within the framework of the RID messages, an Observer can establish within the framework of the RID messages, an Observer can establish
that the DRIP identifier used does uniquely belong to the UAS. That that the DRIP identifier uniquely belong to the UAS. That the only
the only way for any other UAS to assert this DRIP identifier would way for any other UAS to assert this DRIP identifier would be to
be to steal something from within the UAS. The DRIP identifier is steal something from within the UAS. The DRIP identifier is self-
self-generated by the UAS (either UA or GCS) and registered with the generated by the UAS (either UA or GCS) and registered with the USS.
USS.
The data communication of using Broadcast RID faces extreme The Broadcast RID data exchange faces extreme challenges due to the
challenges due to the limitation of the demanding support for limitation of the demanding support for Bluetooth. The ASTM
Bluetooth. The ASTM [F3411-19] defines the basic RID message which [F3411-19] defines the basic RID message which is expected to contain
is expected to contain certain RID data and the Authentication certain RID data and the Authentication message. The Basic RID
message. The Basic RID message has a maximum payload of 25 bytes and message has a maximum payload of 25 bytes and the maximum size
the maximum size allocated by ASTM for the RID is 20 bytes and only 3 allocated by ASTM for the RID is 20 bytes and only 3 bytes are left
bytes are left unused. currently, the authentication maximum payload unused. currently, the authentication maximum payload is defined to
is defined to be 201 bytes. be 201 bytes.
Editor-note 7: To be more specific about the RID message header
and payload structure, such as 1) list different type of BRID
messages defined in ASTM F3411, 2) how many bytes for each filed.
Standard approaches like X.509 and PKI will not fit these Standard approaches like X.509 and PKI will not fit these
constraints, even using the new EdDSA [RFC8032] algorithm cannot fit constraints, even using the new EdDSA [RFC8032] algorithm cannot fit
within the maximum 201 byte limit, due in large measure to ASN.1 within the maximum 201 byte limit, due in large measure to ASN.1
encoding format overhead. encoding format overhead.
An example of a technology that will fit within these limitations is An example of a technology that will fit within these limitations is
an enhancement of the Host Identity Tag (HIT) of HIPv2 [RFC7401] an enhancement of the Host Identity Tag (HIT) of HIPv2 [RFC7401]
using Hierarchical HITs (HHITs) for UAS RID is outlined in HHIT based using Hierarchical HITs (HHITs) for UAS RID [I-D.ietf-drip-rid]. As
UAS RID [I-D.ietf-drip-rid]. As PKI with X.509 is being used in PKI with X.509 is being used in other systems with which UAS RID must
other systems with which UAS RID must interoperate (e.g. Discovery interoperate (e.g. Discovery and Synchronization Service and any
and Synchronization Service and any other communications involving other communications involving USS) mappings between the more
USS) mappings between the more flexible but larger X.509 certificates flexible but larger X.509 certificates and the HHIT-based structures
and the HHIT-based structures must be devised. This could be as in can must be devised. This could be as in [RFC8002] or simply the
[RFC8002] or simply the HHIT as Subject Alternative Name (SAN) and no HHIT as Subject Alternative Name (SAN) and no Distinguished Name
Distinguished Name (DN). (DN).
Editor-note 8: is there a need to explain the how binding/proxy/
translation between the HHIT and X509? Should this be addressed
in Arch- or solution?
A self-attestation of the HHIT RID can be done in as little as 84 A self-attestation of the HHIT RID can be done in as little as 84
bytes, by avoiding an explicit encoding technology like ASN.1 or bytes, by avoiding an explicit encoding technology like ASN.1 or
Concise Binary Object Representation (CBOR [RFC8949]). This Concise Binary Object Representation (CBOR [RFC8949]). This
compressed attestation consists of only the HHIT, a timestamp, and compressed attestation consists of only the HHIT, a timestamp, and
the EdDSA signature on them. The HHIT prefix and suiteID provide the EdDSA signature on them.
crypto agility and implicit encoding rules. Similarly, a self-
attestation of the Hierarchical registration of the RID (an Editor-note 9: to be more specific regarding how HHIT can only use
attestation of a RID third-party registration "certificate") can be as little as 84 bytes to address the crypto concern.
done in 200 bytes. Both these are detailed in UAS RID
[I-D.ietf-drip-rid]. The HHIT prefix and suiteID provide crypto agility and implicit
encoding rules. Similarly, a self-attestation of the Hierarchical
registration of the RID (an attestation of a RID third-party
registration "certificate") can be done in 200 bytes. Both these are
detailed in UAS RID [I-D.ietf-drip-rid].
Editor-note 10: to be more specific why 200 bytes is sufficient.
An Observer would need Internet access to validate a self- An Observer would need Internet access to validate a self-
attestations claim. A third-party Certificate can be validated via a attestations claim. A third-party Certificate can be validated via a
small credential cache in a disconnected environment. This third- small credential cache in a disconnected environment. This third-
party Certificate is possible when the third-party also uses HHITs party Certificate is possible when the third-party also uses HHITs
for its identity and the UA has the public key and the Certificate for its identity and the UA has the public key and the Certificate
for that HHIT. for that HHIT.
4.2. HIT as A Trustworthy DRIP Entity Identifier 4.2. HIT as A Trustworthy DRIP Entity Identifier
Editor-note 15: general comments about rewrite of this section due
to lack of coherence.
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) comes from signing this cryptographic attestation, versus mere claim) is guaranteed by signing this
ID with the associated private key. It is statistically hard for cryptographic ID with the associated private key. The association
between the ID and the private key is ensured by cryptographically
binding the public key with the ID, more specifically the ID results
from the hash of the public key. It is statistically hard for
another entity to create a public key that would generate (spoof) the another entity to create a public key that would generate (spoof) the
ID. ID.
HITs are so designed; they are statistically unique through the The HITs is designed statistically unique through the cryptographic
cryptographic hash feature of second-preimage resistance. The hash feature of second-preimage resistance. The cryptographically-
cryptographically-bound addition of the Hierarchy and an HHIT bound addition of the Hierarchy and an HHIT registration process
registration process (e.g. based on Extensible Provisioning Protocol, (e.g. based on Extensible Provisioning Protocol, [RFC5730]) provide
[RFC5730]) provide complete, global HHIT uniqueness. This complete, global HHIT uniqueness. This registration forces the
registration forces the attacker to generate the same public key attacker to generate the same public key rather than a public key
rather than a public key that generates the same HHIT. This is in that generates the same HHIT. This is in contrast to general IDs
contrast to general IDs (e.g. a UUID or device serial number) as the (e.g. a UUID or device serial number) as the subject in an X.509
subject in an X.509 certificate. certificate.
4.3. HHIT for DRIP Identifier Registration and Lookup
Remote ID needs a deterministic lookup mechanism that rapidly
provides actionable information about the identified UA. Given the
size constraints imposed by the Bluetooth 4 broadcast media, the
Remote ID itself needs to be the inquiry input into the lookup. An
HHIT DRIP identifier contains cryptographically embedded registration
information. This HHIT registration hierarchy, along with the IPv6
prefix, is trustable and sufficient information that can be used to
perform such a lookup. Additionally, the IPv6 prefix can enhance the
HHITs use beyond the basic Remote ID function (e.g use in HIP,
[RFC7401]).
Therefore, a DRIP identifier can be represented as a HHIT. It can be Editor-note 11: Explain how HIT itself and HHIT registry address
self-generated by a UAS (either UA or GCS) and registered with the naming collision.
Private Information Registry (More details in Section 5.2) identified
in its hierarchy fields. Each DRIP identifier represented as an HHIT
can not be used more than once.
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 can only hardware serial number per [CTA2063A]. Such a static HHIT can only
be used to bind one-time use DRIP identifiers to the unique UA. 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 8). possession of the manufacturer (more details in Section 8).
In another case, a UAS equipped for Broadcast RID can be provisioned In another case, a UAS equipped for Broadcast RID can be provisioned
not only with its HHIT but also with the HI public key from which the not only with its HHIT but also with the HI public key from which the
HHIT was derived and the corresponding private key, to enable message HHIT was derived and the corresponding private key, to enable message
signature. A UAS equipped for Network RID can be provisioned signature. A UAS equipped for Network RID can 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 can be provisioned either with public keys of the DRIP device can be provisioned either with public keys of the DRIP
identifier root registries or certificates for subordinate identifier root registries or certificates for subordinate
registries. registries.
HHITs can be used throughout the UAS/UTM system. The Operators, HHITs can also be used throughout the USS/UTM system. The Operators,
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 used with HIP to strongly mutually authenticate and
encrypt communications. encrypt communications.
4.3. HHIT for DRIP Identifier Registration and Lookup
Remote ID needs a deterministic lookup mechanism that rapidly
provides actionable information about the identified UA. Given the
size constraints imposed by the Bluetooth 4 broadcast media, the
Remote ID itself needs to be the inquiry input into the lookup. An
HHIT DRIP identifier contains cryptographically embedded registration
information. This HHIT registration hierarchy, along with the IPv6
prefix, is trustable and sufficient information that can be used to
perform such a lookup. Additionally, the IPv6 prefix can enhance the
HHITs use beyond the basic Remote ID function (e.g use in HIP,
[RFC7401]).
Editor-note 12: more description regarding 1) Is that something we
should address in the Arch- 2) if yes, then adding more text about
how a trustable lookup is performed
Therefore, a DRIP identifier can be represented as a HHIT. It can be
self-generated by a UAS (either UA or GCS) and registered with the
Private Information Registry (More details in Section 5.2) identified
in its hierarchy fields. Each DRIP identifier represented as an HHIT
can not be used more than once.
4.4. HHIT for DRIP Identifier Cryptographic 4.4. HHIT for DRIP Identifier Cryptographic
The only (known to the authors of this document at the time of its The only (known to the authors of this document at the time of its
writing) extant fixed-length ID cryptographically derived from a writing) extant fixed-length ID cryptographically derived from a
public key are the Host Identity Tag [RFC7401], HITs, and public key are the Host Identity Tag [RFC7401], HITs, and
Cryptographically Generated Addresses [RFC3972], CGAs. However, both Cryptographically Generated Addresses [RFC3972], CGAs. However, both
HITs and CGAs lack registration/retrieval capability. HHIT, on the HITs and CGAs lack registration/retrieval capability. HHIT, on the
other hand, is capable of providing a cryptographic hashing function, other hand, is capable of providing a cryptographic hashing function,
along with a registration process to mitigate the probability of a along with a registration process to mitigate the probability of a
hash collision (first registered, first allowed). hash collision (first registered, first allowed).
5. DRIP Identifier Registration and Registries 5. DRIP Identifier Registration and Registries
Editor-note 16: Fundamentally disagree with not actually
specifying an architecture in the DRIP Architecture document (From
Stuart Card)
UAS registries can hold both public and private UAS information UAS registries can 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. A DRIP identifier is amenable to handling in different registries. A DRIP identifier is amenable to handling
as an Internet domain name (at an arbitrary level in the hierarchy). as an Internet domain name (at an arbitrary level in the hierarchy).
It also can be registered in at least a pseudo-domain (e.g. .ip6.arpa It also can be registered in at least a pseudo-domain (e.g. .ip6.arpa
for reverse lookup), or as a sub-domain (for forward lookup). This for reverse lookup), or as a sub-domain (for forward lookup). This
section introduces the public and private information registries for section introduces the public and private information registries for
DRIP identifiers. DRIP identifiers.
skipping to change at page 15, line 18 skipping to change at page 16, line 5
5.2.1. Background 5.2.1. 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. This implies fitting into an ID structure compatible with DNS names. This implies
some sort of hierarchy, for scalability, and management of this some sort of hierarchy, for scalability, and management of this
hierarchy. It is expected that the private registry function will be hierarchy. It is expected that the private registry function will be
provided by the same organizations that run USS, and likely provided by the same organizations that run a USS, and likely
integrated with USS. integrated with a USS.
5.2.2. Proposed Approach 5.2.2. Proposed Approach
A DRIP private information registry can support essential Internet A DRIP private information registry can support essential Internet
domain name registry operations (e.g. add, delete, update, query) domain name registry operations (e.g. add, delete, update, query)
using interoperable open standard protocols. It can also support the using interoperable open standard protocols. It can also support the
Extensible Provisioning Protocol (EPP) and the Registry Data Access Extensible Provisioning Protocol (EPP) and the Registry Data Access
Protocol (RDAP) with access controls. It might be listed in a DNS: Protocol (RDAP) with access controls. It might be listed in a DNS:
that DNS could be private; but absent any compelling reasons for use that DNS could be private; but absent any compelling reasons for use
of private DNS, a public DNS hierarchy needs to be in place. The of private DNS, a public DNS hierarchy needs to be in place. The
skipping to change at page 15, line 42 skipping to change at page 16, line 29
specified in [RFC7484]. A DRIP private information registry can also specified in [RFC7484]. A DRIP private information registry can also
support WebFinger as specified in [RFC7033]. support WebFinger as specified in [RFC7033].
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 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 only specifies Broadcast RID for UAS, however, still RID Final Rules [FAA_RID] only specify Broadcast RID for UAS,
encourages Network RID for complementary functionality, especially in however, still encourages Network RID for complementary
support of UTM. functionality, especially in support of UTM.
One obvious opportunity is to enhance the architecture with gateways One obvious opportunity is to enhance the architecture with gateways
from Broadcast RID to Network RID. This provides the best of both from Broadcast RID to Network RID. This provides the best of both
and gives regulators and operators flexibility. It offers and gives regulators and operators flexibility. It offers
considerable enhancement over some Network RID options such as only considerable enhancement over some Network RID options such as only
reporting planned 4D operation space by the operator. reporting planned 4D operation space by the operator.
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 crowd-sourced (as
nothing more than a smartphone with a suitable app is needed). As nothing more than a smartphone with a suitable app is needed). As
Broadcast RID media have limited range, gateways receiving messages Broadcast RID media have limited range, gateways receiving messages
claiming locations far from the gateway can alert authorities or a claiming locations far from the gateway can alert authorities or a
SDSP to the failed sanity check possibly indicating intent to SDSP to the failed sanity check possibly indicating intent to
deceive. Surveillance SDSPs can use messages with precise date/time/ deceive. Surveillance SDSPs can use messages with precise date/time/
position stamps from the gateways to multilaterate UA location, position stamps from the gateways to multilaterate UA location,
independent of the locations claimed in the messages (which may have independent of the locations claimed in the messages (which may have
a natural time lag as it is), which are entirely operator self- a natural time lag as it is), which are entirely operator self-
reported in UAS RID and UTM. reported in UAS RID and UTM, and thus are subject not only to natural
time lag and error but also operator 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.
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
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 can not interface directly with Broadcast RID receiver. However, it should not depend upon a direct
a GCS, Net-RID SP, Net-RID DP or Network RID client. It would interface with a GCS, Net-RID SP, Net-RID DP or Network RID client.
present a TBD interface to a CS-RID SDSP; this interface needs to be It would present a TBD interface to a CS-RID SDSP; this interface
based upon but readily distinguishable from that between a GCS and a should be based upon but readily distinguishable from that between a
Net-RID SP. GCS and a Net-RID SP.
6.2. The CS-RID SDSP 6.2. The CS-RID SDSP
A CS-RID SDSP would appear (i.e. present the same interface) to a A CS-RID SDSP would present a TBD interface to a CS-RID Finder; this
Net-RID SP as a Net-RID DP. A CS-RID SDSP can not present a standard interface should be based upon but readily distinguishable from that
GCS-facing interface as if it were a Net-RID SP. A CS-RID SDSP would between a GCS and a Net-RID SP. A CS-RID SDSP should appear (i.e.
present a TBD interface to a CS-RID Finder; this interface can be present the same interface) to a Net-RID SP as a Net-RID DP.
based upon but readily distinguishable between a GCS and a Net-RID
SP.
7. Privacy for Broadcast PII
Broadcast RID messages can contain PII. A viable architecture for
PII protection would be symmetric encryption of the PII using a key
known to the UAS and its USS. An authorized Observer could send the
encrypted PII along with the UAS ID (to entities such as USS of the
Observer, or to the UAS in which the UAS ID is registered if that can
be determined from the UAS ID itself or to a Public Safety USS) to
get the plaintext. Alternatively, the authorized Observer can
receive the key to directly decrypt all future PII content from the
UA.
PII can be protected unless the UAS is informed otherwise. This 7. IANA Consideration
could come from operational instructions to even permit flying in a
space/time. It can be special instructions at the start or during an
operation. PII protection can not be used if the UAS loses
connectivity to the USS. The UAS always has the option to abort the
operation if PII protection is disallowed.
An authorized Observer can instruct a UAS via the USS that conditions This document does not make any IANA request.
have changed mandating no PII protection or land the UA (abort the
operation).
8. Security Considerations 8. 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.
9. Acknowledgements 9. Privacy & Transparency Considerations
The work of the FAA's UAS Identification and Tracking (UAS ID) Broadcast RID messages can contain PII. A viable architecture for
Aviation Rulemaking Committee (ARC) is the foundation of later ASTM PII protection would be symmetric encryption of the PII using a
and proposed IETF DRIP WG efforts. The work of ASTM F38.02 in session key known to the UAS and its USS. An authorized Observer
balancing the interests of diverse stakeholders is essential to the could send the encrypted PII along with the UAS ID (to the USS in
necessary rapid and widespread deployment of UAS RID. IETF which the UAS ID is registered if that can be determined, e.g., from
volunteers who have contributed to this draft include Amelia received Broadcast RID information such as the UAS ID itself, or to
Andersdotter and Mohamed Boucadair. the Observer's USS, or to a Public Safety USS) to get the plaintext.
Alternatively, the authorized Observer can receive the key to
directly decrypt all PII content sent by that UA during that session
(UAS operation).
An authorized Observer can instruct a UAS via the USS that conditions
have changed mandating no PII protection or land the UA (abort the
operation).
PII can be protected unless the UAS is informed otherwise. This
could come as part of UTM operation authorization. It can be special
instructions at the start or during an operation. PII protection can
not be used if the UAS loses connectivity to the USS. The UAS always
has the option to abort the operation if PII protection is
disallowed.
10. References 10. References
10.1. Normative References 10.1. 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-12, 23 May 2021, ietf-drip-reqs-17, 7 July 2021,
<https://www.ietf.org/archive/id/draft-ietf-drip-reqs- <https://www.ietf.org/archive/id/draft-ietf-drip-reqs-
12.txt>. 17.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>.
skipping to change at page 20, line 41 skipping to change at page 21, line 20
[RFC8392] Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig, [RFC8392] Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig,
"CBOR Web Token (CWT)", RFC 8392, DOI 10.17487/RFC8392, "CBOR Web Token (CWT)", RFC 8392, DOI 10.17487/RFC8392,
May 2018, <https://www.rfc-editor.org/info/rfc8392>. May 2018, <https://www.rfc-editor.org/info/rfc8392>.
[RFC8949] Bormann, C. and P. Hoffman, "Concise Binary Object [RFC8949] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", STD 94, RFC 8949, Representation (CBOR)", STD 94, RFC 8949,
DOI 10.17487/RFC8949, December 2020, DOI 10.17487/RFC8949, December 2020,
<https://www.rfc-editor.org/info/rfc8949>. <https://www.rfc-editor.org/info/rfc8949>.
[TS-22.825] [TS-22.825]
3GPP, "UAS RID requirement study", n.d., 3GPP, "Study on Remote Identification of Unmanned Aerial
Systems (UAS)", n.d.,
<https://portal.3gpp.org/desktopmodules/Specifications/ <https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3527>. SpecificationDetails.aspx?specificationId=3527>.
[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", 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 Unmanned Aircraft Systems (UAS) Traffic
Management (UTM) Management (UTM)
A.1. Operation Concept A.1. Operation Concept
The National Aeronautics and Space Administration (NASA) and FAAs' The National Aeronautics and Space Administration (NASA) and FAA's
effort of integrating UAS's operation into the national airspace effort of integrating UAS's operation into the national airspace
system (NAS) leads to the development of the concept of UTM and the system (NAS) led to the development of the concept of UTM and the
ecosystem around it. The UTM concept was initially presented in 2013 ecosystem around it. The UTM concept was initially presented in 2013
and version 2.0 is published in 2020 [FAA_UAS_Concept_Of_Ops]. and version 2.0 was published in 2020 [FAA_UAS_Concept_Of_Ops].
The eventual development and implementation are conducted by the UTM The eventual concept refinement, initial prototype implementation and
research transition team which is the joint workforce by FAA and testing were conducted by the UTM research transition team which is
NASA. World efforts took place afterward. The Single European Sky the joint workforce by FAA and NASA. World efforts took place
ATM Research (SESAR) started the CORUS project to research its UTM afterward. The Single European Sky ATM Research (SESAR) started the
counterpart concept, namely [U-Space]. This effort is led by the CORUS project to research its UTM counterpart concept, namely
European Organization for the Safety of Air Navigation (Eurocontrol). [U-Space]. This effort is led by the European Organization for the
Safety of Air Navigation (Eurocontrol).
Both NASA and SESAR have published the UTM concept of operations to Both NASA and SESAR have published the UTM concept of operations to
guide the development of their future air traffic management (ATM) guide the development of their future air traffic management (ATM)
system and make sure safe and efficient integrations of manned and system and ensure safe and efficient integrations of manned and
unmanned aircraft into the national airspace. unmanned aircraft into the national airspace.
The UTM composes of UAS operation infrastructure, procedures and The UTM comprises UAS operation infrastructure, procedures and local
local regulation compliance policies to guarantee UAS's safe regulation compliance policies to guarantee safe UAS integration and
integration and operation. The main functionality of a UTM includes, operation. The main functionality of a UTM includes, but is not
but is not limited to, providing means of communication between UAS limited to, providing means of communication between UAS operators
operators and service providers and a platform to facilitate and service providers and a platform to facilitate communication
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 a UTM has to offer. Such Entity acts as a indicators (KPIs) that a UTM has to offer. Such 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 monitor 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(s) to build a large service coverage map which coexist with other USS to build a large service coverage map which
can load-balance, relay and share UAS traffic information. can 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 UTM envisioned which is the first system to realize some of the UTM envisioned
functionality. The LAANC program can automate the UAS's flight plan functionality. The LAANC program can automate the UAS's flight plan
application and approval process for airspace authorization in real- application and approval process for airspace authorization in real-
time by checking against multiple aeronautical databases such as time by checking against multiple aeronautical databases such as
airspace classification and fly rules associated with it, FAA UAS airspace classification and fly rules associated with it, FAA UAS
facility map, special use airspace, Notice to Airman (NOTAM), and facility map, special use airspace, Notice to Airman (NOTAM), and
Temporary Flight Rule (TFR). Temporary Flight Rule (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 takeoff or land in a 1. For a UAS participating in UTM and taking off or landing in a
controlled airspace (e.g., Class Bravo, Charlie, Delta and Echo controlled airspace (e.g., Class Bravo, Charlie, Delta and Echo
in United States), the USS where UAS is currently communicating in the United States), the USS under which the UAS is operating
with is responsible for UAS's registration, authenticating the is responsible for verifying UA registration, authenticating the
UAS's fly plan by checking against designated UAS fly map UAS operational intent (flight plan) by checking against
database, obtaining the air traffic control (ATC) authorization designated UAS fly map database, obtaining the air traffic
and monitor the UAS fly path in order to maintain safe boundary control (ATC) authorization and monitor the UAS flight path in
and follow the pre-authorized route. order to maintain safe margins and follow the pre-authorized
sequence of authorized 4-D volumes (route).
2. For a UAS participating in UTM and take off or land in an 2. For a UAS participating in UTM and taking off or landing in an
uncontrolled airspace (ex. Class Golf in the United States), uncontrolled airspace (ex. Class Golf in the United States),
pre-fly authorization must be obtained from a USS when operating pre-flight authorization must be obtained from a USS when
beyond-visual-of-sight (BVLOS) operation. The USS either accepts operating beyond-visual-of-sight (BVLOS). The USS either accepts
or rejects received intended fly plan from the UAS. Accepted UAS or rejects received operational intent (flight plan) from the
operation may share its current fly data such as GPS position and UAS. Accepted UAS operation may share its current flight data
altitude to USS. The USS may keep the UAS operation status near such as GPS position and altitude to USS. The USS may keep the
real-time and may keep it as a record for overall airspace air UAS operation status near real-time and may keep it as a record
traffic monitor. for overall airspace air traffic monitoring.
A.4. 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 The ADS-B is the de jure technology used in manned aviation for
sharing location information, from the aircraft to ground and sharing location information, from the aircraft to ground and
satellite-based systems, designed in the early 2000s. Broadcast RID satellite-based systems, designed in the early 2000s. Broadcast RID
is conceptually similar to ADS-B, but with the receiver target being is conceptually similar to ADS-B, but with the receiver target being
the general public on generally available devices (e.g. smartphones). the general public on generally available devices (e.g. 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 UA. Technical reasons include but not limited to the flying small UA. Technical reasons include but not limited to the
following: following:
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2. Weight and cost of ADS-B transponders on CSWaP constrained UA 2. Weight and cost of ADS-B 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.
Acknowledgements
The work of the FAA's UAS Identification and Tracking (UAS ID)
Aviation Rulemaking Committee (ARC) is the foundation of later ASTM
and proposed IETF DRIP WG efforts. The work of ASTM F38.02 in
balancing the interests of diverse stakeholders is essential to the
necessary rapid and widespread deployment of UAS RID. IETF
volunteers who have contributed to this draft include Amelia
Andersdotter and Mohamed Boucadair.
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
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