rfc9575v2.txt   rfc9575.txt 
Internet Engineering Task Force (IETF) A. Wiethuechter, Ed. Internet Engineering Task Force (IETF) A. Wiethuechter, Ed.
Request for Comments: 9575 S. Card Request for Comments: 9575 S. Card
Category: Standards Track AX Enterprize, LLC Category: Standards Track AX Enterprize, LLC
ISSN: 2070-1721 R. Moskowitz ISSN: 2070-1721 R. Moskowitz
HTT Consulting HTT Consulting
May 2024 May 2024
DRIP Entity Tag Authentication Formats and Protocols for Broadcast DRIP Entity Tag (DET) Authentication Formats and Protocols for Broadcast
Remote Identification Remote Identification (RID)
Abstract Abstract
The Drone Remote Identification Protocol (DRIP), plus trust policies The Drone Remote Identification Protocol (DRIP), plus trust policies
and periodic access to registries, augments Unmanned Aircraft System and periodic access to registries, augments Unmanned Aircraft System
(UAS) Remote Identification (RID), enabling local real-time (UAS) Remote Identification (RID), enabling local real-time
assessment of trustworthiness of received RID messages and observed assessment of trustworthiness of received RID messages and observed
UAS, even by Observers lacking Internet access. This document UAS, even by Observers lacking Internet access. This document
defines DRIP message types and formats to be sent in Broadcast RID defines DRIP message types and formats to be sent in Broadcast RID
Authentication Messages to verify that attached and recently detached Authentication Messages to verify that attached and recently detached
skipping to change at line 68 skipping to change at line 68
2. Terminology 2. Terminology
2.1. Required Terminology 2.1. Required Terminology
2.2. Definitions 2.2. Definitions
3. UAS RID Authentication Background and Procedures 3. UAS RID Authentication Background and Procedures
3.1. DRIP Authentication Protocol Description 3.1. DRIP Authentication Protocol Description
3.1.1. Usage of DNS 3.1.1. Usage of DNS
3.1.2. Providing UAS RID Trust 3.1.2. Providing UAS RID Trust
3.2. ASTM Authentication Message Framing 3.2. ASTM Authentication Message Framing
3.2.1. Authentication Page 3.2.1. Authentication Page
3.2.2. Authentication Payload Field 3.2.2. Authentication Payload Field
3.2.3. Specific Authentication Method (SAM) 3.2.3. SAM Data Format
3.2.4. ASTM Broadcast RID Constraints 3.2.4. ASTM Broadcast RID Constraints
4. DRIP Authentication Formats 4. DRIP Authentication Formats
4.1. UA-Signed Evidence Structure 4.1. UA-Signed Evidence Structure
4.2. DRIP Link 4.2. DRIP Link
4.3. DRIP Wrapper 4.3. DRIP Wrapper
4.3.1. Wrapped Count and Format Validation 4.3.1. Wrapped Count and Format Validation
4.3.2. Wrapper over Extended Transports 4.3.2. Wrapper over Extended Transports
4.3.3. Wrapper Limitations 4.3.3. Wrapper Limitations
4.4. DRIP Manifest 4.4. DRIP Manifest
4.4.1. Hash Count and Format Validation 4.4.1. Hash Count and Format Validation
skipping to change at line 182 skipping to change at line 182
Administration (FAA) [FAA-14CFR], which is missing from [F3411] over Administration (FAA) [FAA-14CFR], which is missing from [F3411] over
Legacy Transports (Bluetooth 4.x). Legacy Transports (Bluetooth 4.x).
These DRIP enhancements to ASTM's specification for RID and tracking These DRIP enhancements to ASTM's specification for RID and tracking
[F3411] further support the important use case of Observers who may [F3411] further support the important use case of Observers who may
be offline at the time of observation. be offline at the time of observation.
Section 7 summarizes the DRIP requirements [RFC9153] addressed Section 7 summarizes the DRIP requirements [RFC9153] addressed
herein. herein.
Note: The Endorsement (used in Section 4.2) that proves that a DET is
registered MUST come from its immediate parent in the registration
hierarchy, e.g., a DRIP Identity Management Entity (DIME) [DRIP-REG].
In the definitive hierarchy, the parent of the UA is its HHIT Domain
Authority (HDA), the parent of an HDA is its Registered Assigning
Authority (RAA), etc. It is also assumed that all DRIP-aware
entities use a DET as their identifier during interactions with other
DRIP-aware entities.
2. Terminology 2. Terminology
2.1. Required Terminology 2.1. Required 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 "OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
skipping to change at line 221 skipping to change at line 212
802.11 Beacons with the vendor-specific information element as 802.11 Beacons with the vendor-specific information element as
specified in [F3411]. Must use ASTM Message Pack (Message Type specified in [F3411]. Must use ASTM Message Pack (Message Type
0xF). 0xF).
Legacy Transports: Use of broadcast frames (Bluetooth 4.x) as Legacy Transports: Use of broadcast frames (Bluetooth 4.x) as
specified in [F3411]. specified in [F3411].
Manifest: An immutable list of items being transported (in this Manifest: An immutable list of items being transported (in this
specific case over wireless communication). specific case over wireless communication).
Note: For the remainder of this document, Broadcast Endorsement:
Parent, Child will be abbreviated as BE: Parent, Child. For example,
Broadcast Endorsement: RAA, HDA will be abbreviated as BE: RAA, HDA.
3. UAS RID Authentication Background and Procedures 3. UAS RID Authentication Background and Procedures
3.1. DRIP Authentication Protocol Description 3.1. DRIP Authentication Protocol Description
[F3411] defines Authentication Message framing only. It does not [F3411] defines Authentication Message framing only. It does not
define authentication formats or methods. It explicitly anticipates define authentication formats or methods. It explicitly anticipates
several signature options but does not fully define those. Annex A1 several signature options but does not fully define those. Annex A1
of [F3411] defines a Broadcast Authentication Verifier Service, which of [F3411] defines a Broadcast Authentication Verifier Service, which
has a heavy reliance on Observer real-time connectivity to the has a heavy reliance on Observer real-time connectivity to the
Internet. Fortunately, [F3411] also allows third-party standard Internet. Fortunately, [F3411] also allows third-party standard
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trust assessment (Section 6.4.2). trust assessment (Section 6.4.2).
3.1.2.1. DIME Endorsements of Subordinate DETs 3.1.2.1. DIME Endorsements of Subordinate DETs
Observers receive DRIP Link Authentication Messages (Section 4.2) Observers receive DRIP Link Authentication Messages (Section 4.2)
containing Broadcast Endorsements by DIMEs of child DET containing Broadcast Endorsements by DIMEs of child DET
registrations. A series of these Endorsements confirms a path registrations. A series of these Endorsements confirms a path
through the hierarchy, defined in [DRIP-REG], from the DET Prefix through the hierarchy, defined in [DRIP-REG], from the DET Prefix
Owner all the way to an individual UA DET registration. Owner all the way to an individual UA DET registration.
Note: For the remainder of this document, Broadcast Endorsement:
Parent, Child will be abbreviated as BE: Parent, Child. For example,
Broadcast Endorsement: RAA, HDA will be abbreviated as BE: RAA, HDA.
3.1.2.2. UA-Signed Evidence 3.1.2.2. UA-Signed Evidence
To prove possession of the private key associated with the DET, the To prove possession of the private key associated with the DET, the
UA MUST sign and send data that is unique and unpredictable but UA MUST sign and send data that is unique and unpredictable but
easily validated by the Observer. The data can be an ASTM Message easily validated by the Observer. The data can be an ASTM Message
that fulfills the requirements to be unpredictable but easily that fulfills the requirements to be unpredictable but easily
validated. An Observer receives this UA-signed Evidence from DRIP- validated. An Observer receives this UA-signed Evidence from DRIP-
based Authentication Messages (Sections 4.3 or 4.4). based Authentication Messages (Sections 4.3 or 4.4).
Whether the content is true is a separate question that DRIP cannot Whether the content is true is a separate question that DRIP cannot
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3.2. ASTM Authentication Message Framing 3.2. ASTM Authentication Message Framing
The Authentication Message (Message Type 0x2) is unique in the ASTM The Authentication Message (Message Type 0x2) is unique in the ASTM
[F3411] Broadcast standard, as it is the only message that can be [F3411] Broadcast standard, as it is the only message that can be
larger than the Legacy Transport size. To address this limitation larger than the Legacy Transport size. To address this limitation
around transport size, it is defined as a set of "pages", each of around transport size, it is defined as a set of "pages", each of
which fits into a single Legacy Transport frame. For Extended which fits into a single Legacy Transport frame. For Extended
Transports, pages are still used but they are all in a single frame. Transports, pages are still used but they are all in a single frame.
Informational Note: Message Pack (Message Type 0xF) is also larger | Informational Note: Message Pack (Message Type 0xF) is also
than the Legacy Transport size but is limited for use only on | larger than the Legacy Transport size but is limited for use
Extended Transports where it can be supported. | only on Extended Transports where it can be supported.
The following subsections are a brief overview of the Authentication The following subsections are a brief overview of the Authentication
Message format defined in [F3411] for better context on how DRIP Message format defined in [F3411] for better context on how DRIP
Authentication fills and uses various fields already defined by ASTM Authentication fills and uses various fields already defined by ASTM
[F3411]. [F3411].
3.2.1. Authentication Page 3.2.1. Authentication Page
This document leverages Authentication Type 0x5 (Specific This document leverages Authentication Type 0x5 (Specific
Authentication Method (SAM)) as the principal authentication Authentication Method (SAM)) as the principal authentication
container, defining a set of SAM Types in Section 4. Authentication container, defining a set of SAM Types in Section 4. Authentication
Type is encoded in every Authentication Page in the _Page Header_. Type is encoded in every Authentication Page in the _Page Header_.
The SAM Type is defined as a field in the _Authentication Payload_ The SAM Type is defined as a field in the _Authentication Payload_
(see Section 3.2.3.1). (see Section 3.2.3).
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| Page Header | | | Page Header | |
+---------------+ | +---------------+ |
| | | |
| | | |
| Authentication Payload | | Authentication Payload |
| | | |
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
Figure 1: Standard ASTM Authentication Message Page Figure 1: Standard ASTM Authentication Message Page
Page Header: (1 octet) _Page Header_: (1 octet)
Authentication Type (4 bits) and Page Number (4 bits) Authentication Type (4 bits) and Page Number (4 bits)
Authentication Payload: (23 octets per page) _Authentication Payload_: (23 octets per page)
Authentication Payload, including headers. Null padded. See Authentication Payload, including headers. Null padded. See
Section 3.2.2. Section 3.2.2.
The Authentication Message is structured as a set of pages per The Authentication Message is structured as a set of pages per
Figure 1. There is a technical maximum of 16 pages (indexed 0 to 15) Figure 1. There is a technical maximum of 16 pages (indexed 0 to 15)
that can be sent for a single Authentication Message, with each page that can be sent for a single Authentication Message, with each page
carrying a maximum 23-octet Authentication Payload. See carrying a maximum 23-octet _Authentication Payload_. See
Section 3.2.4 for more details. Over Legacy Transports, these Section 3.2.4 for more details. Over Legacy Transports, these
messages are "fragmented", with each page sent in a separate Legacy messages are "fragmented", with each page sent in a separate Legacy
Transport frame. Transport frame.
Either as a single Authentication Message or a set of fragmented Either as a single Authentication Message or a set of fragmented
Authentication Message Pages, the structure is further wrapped by Authentication Message Pages, the structure is further wrapped by
outer ASTM framing and the specific link framing. outer ASTM framing and the specific link framing.
3.2.2. Authentication Payload Field 3.2.2. Authentication Payload Field
Figure 2 is the source data view of the data fields found in the Figure 2 is the source data view of the data fields found in the
Authentication Message as defined by [F3411]. This data is placed Authentication Message as defined by [F3411]. This data is placed
into the Authentication Payload shown in Figure 1, which spans into the _Authentication Payload_ shown in Figure 1, which spans
multiple Authentication Pages. multiple _Authentication Pages_.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| Authentication Headers | | Authentication Headers |
| +---------------+---------------+ | +---------------+---------------+
| | | | | |
+---------------+---------------+ | +---------------+---------------+ |
. . . .
. Authentication Data / Signature . . Authentication Data / Signature .
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| ADL | | | ADL | |
+---------------+ | +---------------+ |
. . . .
. Additional Data . . Additional Data .
. . . .
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
Figure 2: ASTM Authentication Message Fields Figure 2: ASTM Authentication Message Fields
Authentication Headers: (6 octets) _Authentication Headers_: (6 octets)
As defined in [F3411]. As defined in [F3411].
Authentication Data / Signature: (0 to 255 octets) _Authentication Data / Signature_: (0 to 255 octets)
Opaque authentication data. The length of this payload is known Opaque authentication data. The length of this payload is known
through a field in the Authentication Headers (defined in through a field in the _Authentication Headers_ (defined in
[F3411]). [F3411]).
Additional Data Length (ADL): (1 octet - unsigned) _Additional Data Length (ADL)_: (1 octet - unsigned)
Length in octets of Additional Data. The value of ADL is Length in octets of _Additional Data_. The value of _ADL_ is
calculated as the minimum of 361 - Authentication Data / Signature calculated as the minimum of 361 - Authentication Data / Signature
Length and 255. Only present with Additional Data. Length and 255. Only present with _Additional Data_.
Additional Data: (ADL octets) _Additional Data:_ (_ADL_ octets)
Data that follows the Authentication Data / Signature but is not Data that follows the _Authentication Data / Signature_ but is not
considered part of the Authentication Data, and thus is not considered part of the _Authentication Data_, and thus is not
covered by a signature. For DRIP, this field is used to carry covered by a signature. For DRIP, this field is used to carry
Forward Error Correction (FEC) generated by transmitters and Forward Error Correction (FEC) generated by transmitters and
parsed by receivers as defined in Section 5. parsed by receivers as defined in Section 5.
3.2.3. Specific Authentication Method (SAM) 3.2.3. SAM Data Format
3.2.3.1. SAM Data Format
Figure 3 is the general format to hold authentication data when using Figure 3 is the general format to hold authentication data when using
SAM and is placed inside the Authentication Data / Signature field in SAM and is placed inside the _Authentication Data / Signature_ field
Figure 2. in Figure 2.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| SAM Type | | | SAM Type | |
+---------------+ | +---------------+ |
. . . .
. SAM Authentication Data . . SAM Authentication Data .
. . . .
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
Figure 3: SAM Data Format Figure 3: SAM Data Format
SAM Type: (1 octet) _SAM Type_: (1 octet)
The following SAM Types are allocated to DRIP: The following SAM Types are allocated to DRIP:
+==========+=============================+ +==========+=============================+
| SAM Type | Description | | SAM Type | Description |
+==========+=============================+ +==========+=============================+
| 0x01 | DRIP Link (Section 4.2) | | 0x01 | DRIP Link (Section 4.2) |
+----------+-----------------------------+ +----------+-----------------------------+
| 0x02 | DRIP Wrapper (Section 4.3) | | 0x02 | DRIP Wrapper (Section 4.3) |
+----------+-----------------------------+ +----------+-----------------------------+
| 0x03 | DRIP Manifest (Section 4.4) | | 0x03 | DRIP Manifest (Section 4.4) |
+----------+-----------------------------+ +----------+-----------------------------+
| 0x04 | DRIP Frame (Section 4.5) | | 0x04 | DRIP Frame (Section 4.5) |
+----------+-----------------------------+ +----------+-----------------------------+
Table 1: DRIP SAM Types Table 1: DRIP SAM Types
Note: ASTM International is the owner of these code points as they | Note: ASTM International is the owner of these code points as
are defined in [F3411]. In accordance with Annex 5 of [F3411], the | they are defined in [F3411]. In accordance with Annex 5 of
International Civil Aviation Organization (ICAO) has been selected by | [F3411], the International Civil Aviation Organization (ICAO)
ASTM as the registrar to manage allocations of these code points. | has been selected by ASTM as the registrar to manage
The list is available at [ASTM-Remote-ID]. | allocations of these code points. The list is available at
| [ASTM-Remote-ID].
SAM Authentication Data: (0 to 200 octets) _SAM Authentication Data_: (0 to 200 octets)
Contains opaque authentication data formatted as defined by the Contains opaque authentication data formatted as defined by the
preceding SAM Type. preceding SAM Type.
3.2.4. ASTM Broadcast RID Constraints 3.2.4. ASTM Broadcast RID Constraints
3.2.4.1. Wireless Frame Constraints 3.2.4.1. Wireless Frame Constraints
A UA has the option to broadcast using Bluetooth (4.x and 5.x), Wi-Fi A UA has the option to broadcast using Bluetooth (4.x and 5.x), Wi-Fi
NAN, or IEEE 802.11 Beacon; see Section 6. With Bluetooth, FAA and NAN, or IEEE 802.11 Beacon; see Section 6. With Bluetooth, FAA and
other Civil Aviation Authorities (CAA) mandate transmitting other Civil Aviation Authorities (CAA) mandate transmitting
simultaneously over both 4.x and 5.x. The same application-layer simultaneously over both 4.x and 5.x. The same application-layer
information defined in [F3411] MUST be transmitted over all the information defined in [F3411] MUST be transmitted over all the
physical-layer interfaces performing RID, because Observer transports physical-layer interfaces performing RID, because Observer transports
may be limited. If an Observer can support multiple transports, it may be limited. If an Observer can support multiple transports, it
SHOULD uses (display, report, etc.) the latest data regardless of the SHOULD use (display, report, etc.) the latest data regardless of the
transport over which that data was received. transport over which that data was received.
Bluetooth 4.x presents a payload-size challenge in that it can only Bluetooth 4.x presents a payload-size challenge in that it can only
transmit 25 octets of payload per frame, while other transports can transmit 25 octets of payload per frame, while other transports can
support larger payloads per frame. As [F3411] message formats are support larger payloads per frame. As [F3411] message formats are
the same for all media, and their framing was designed to fit within the same for all media, and their framing was designed to fit within
these legacy constraints, Extended Transports cannot send larger these legacy constraints, Extended Transports cannot send larger
messages; instead, the Message Pack format encapsulates multiple messages; instead, the Message Pack format encapsulates multiple
messages (each of which fits within these legacy constraints). messages (each of which fits within these legacy constraints).
skipping to change at line 532 skipping to change at line 522
To keep consistent formatting across the different transports (Legacy To keep consistent formatting across the different transports (Legacy
and Extended) and their independent restrictions, the authentication and Extended) and their independent restrictions, the authentication
data being sent is REQUIRED to fit within the page limit that the data being sent is REQUIRED to fit within the page limit that the
most constrained existing transport can support. Under Broadcast most constrained existing transport can support. Under Broadcast
RID, the Extended Transport that can hold the least amount of RID, the Extended Transport that can hold the least amount of
authentication data is Bluetooth 5.x at 9 pages. authentication data is Bluetooth 5.x at 9 pages.
As such, DRIP transmitters are REQUIRED to adhere to the following As such, DRIP transmitters are REQUIRED to adhere to the following
when using the Authentication Message: when using the Authentication Message:
1. Authentication Data / Signature data MUST fit in the first 9 1. _Authentication Data / Signature_ data MUST fit in the first 9
pages (Page Numbers 0 through 8). pages (Page Numbers 0 through 8).
2. The Length field in the Authentication Headers (which encodes the 2. The _Length_ field in the _Authentication Headers_ (which encodes
length in octets of Authentication Data / Signature only) MUST the length in octets of _Authentication Data / Signature_ only)
NOT exceed the value of 201. This includes the SAM Type but MUST NOT exceed the value of 201. This includes the SAM Type but
excludes Additional Data. excludes _Additional Data_.
3.2.4.3. Timestamps 3.2.4.3. Timestamps
In ASTM [F3411], timestamps are a Unix-style timestamp with an epoch In ASTM [F3411], timestamps are a Unix-style timestamp with an epoch
of 2019-01-01 00:00:00 UTC. For DRIP, this format is adopted for of 2019-01-01 00:00:00 UTC. For DRIP, this format is adopted for
Authentication to keep a common time format in Broadcast payloads. Authentication to keep a common time format in Broadcast payloads.
Under DRIP, there are two timestamps defined: Valid Not Before (VNB) Under DRIP, there are two timestamps defined: Valid Not Before (VNB)
and Valid Not After (VNA). and Valid Not After (VNA).
skipping to change at line 560 skipping to change at line 550
Timestamp denoting the recommended time at which to start trusting Timestamp denoting the recommended time at which to start trusting
data. MUST follow the format defined in [F3411] as described data. MUST follow the format defined in [F3411] as described
above. MUST be set no earlier than the time the signature (across above. MUST be set no earlier than the time the signature (across
a given structure) is generated. a given structure) is generated.
Valid Not After (VNA) Timestamp: (4 octets) Valid Not After (VNA) Timestamp: (4 octets)
Timestamp denoting the recommended time at which to stop trusting Timestamp denoting the recommended time at which to stop trusting
data. MUST follow the format defined in [F3411] as described data. MUST follow the format defined in [F3411] as described
above. Has an additional offset to push a short time into the above. Has an offset (relative to VNB) to avoid replay attacks.
future (relative to VNB) to avoid replay attacks. The exact The exact offset is not defined in this document. Best practice
offset is not defined in this document. Best practice for for identifying an acceptable offset should be used and should
identifying an acceptable offset should be used and should take take into consideration the UA environment, propagation
into consideration the UA environment, propagation characteristics characteristics of the messages being sent, and clock differences
of the messages being sent, and clock differences between the UA between the UA and Observers. For UA signatures in scenarios
and Observers. For UA signatures in scenarios typical as of 2024, typical as of 2024, a reasonable offset would be to set VNA
a reasonable offset would be to set VNA approximately 2 minutes approximately 2 minutes after VNB; see Appendix B for examples
after VNB; see Appendix B for examples that may aid in tuning this that may aid in tuning this value.
value.
4. DRIP Authentication Formats 4. DRIP Authentication Formats
All formats defined in this section are contained in the All formats defined in this section are contained in the
Authentication Data / Signature field in Figure 2 and use the _Authentication Data / Signature_ field in Figure 2 and use the
Specific Authentication Method (SAM, Authentication Type 0x5). The Specific Authentication Method (SAM, Authentication Type 0x5). The
first octet of the Authentication Data / Signature of Figure 2 is first octet of the _Authentication Data / Signature_ of Figure 2 is
used to multiplex among these various formats. used to multiplex among these various formats.
When sending data over a medium that does not have underlying FEC, When sending data over a medium that does not have underlying FEC,
for example Legacy Transports, then FEC Section 5 MUST be used. for example Legacy Transports, then FEC (per Section 5) MUST be used.
Examples of Link, Wrapper, and Manifest are shown as part of an Examples of Link, Wrapper, and Manifest are shown as part of an
operational schedule in Appendix B.2.1. operational schedule in Appendix B.2.1.
4.1. UA-Signed Evidence Structure 4.1. UA-Signed Evidence Structure
The UA-Signed Evidence Structure (Figure 4) is used by the UA during The _UA-Signed Evidence Structure_ (Figure 4) is used by the UA
flight to sign over information elements using the private key during flight to sign over information elements using the private key
associated with the current UA DET. It is encapsulated by the SAM associated with the current UA DET. It is encapsulated by the _SAM
Authentication Data field of Figure 3. Authentication Data_ field of Figure 3.
This structure is used by the DRIP Wrapper (Section 4.3), Manifest This structure is used by the DRIP Wrapper (Section 4.3), Manifest
Section 4.4), and Frame (Section 4.5). DRIP Link (Section 4.2) MUST (Section 4.4), and Frame (Section 4.5). DRIP Link (Section 4.2) MUST
NOT use it, as it will not fit in the ASTM Authentication Message NOT use it, as it will not fit in the ASTM Authentication Message
with its intended content (i.e., a Broadcast Endorsement). with its intended content (i.e., a Broadcast Endorsement).
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| VNB Timestamp by UA | | VNB Timestamp by UA |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| VNA Timestamp by UA | | VNA Timestamp by UA |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
skipping to change at line 635 skipping to change at line 624
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
Figure 4: Endorsement Structure for UA-Signed Evidence Figure 4: Endorsement Structure for UA-Signed Evidence
Valid Not Before (VNB) Timestamp by UA: (4 octets) _Valid Not Before (VNB) Timestamp by UA_: (4 octets)
See Section 3.2.4.3. Set by the UA. See Section 3.2.4.3. Set by the UA.
Valid Not After (VNA) Timestamp by UA: (4 octets) _Valid Not After (VNA) Timestamp by UA_: (4 octets)
See Section 3.2.4.3. Set by the UA. See Section 3.2.4.3. Set by the UA.
Evidence: (0 to 112 octets) _Evidence_: (0 to 112 octets)
The Evidence field MUST be filled in with data in the form of an The _Evidence_ field MUST be filled in with data in the form of an
opaque object specified in the DRIP Wrapper (Section 4.3), opaque object specified in the DRIP Wrapper (Section 4.3),
Manifest (Section 4.4), or Frame (Section 4.5). Manifest (Section 4.4), or Frame (Section 4.5).
UA DRIP Entity Tag: (16 octets) _UA DRIP Entity Tag_: (16 octets)
This is a DET [RFC9374] currently being used by the UA for This is a DET [RFC9374] currently being used by the UA for
authentication; it is assumed to be a Specific Session ID (a type authentication; it is assumed to be a Specific Session ID (a type
of UAS ID typically also used by the UA in the Basic ID Message). of UAS ID typically also used by the UA in the Basic ID Message).
UA Signature: (64 octets) _UA Signature_: (64 octets)
Signature over the concatenation of preceding fields (VNB, VNA, Signature over the concatenation of preceding fields (_VNB_,
Evidence, and UA DET) using the keypair of the UA DET. The _VNA_, _Evidence_, and _UA DET_) using the keypair of the UA DET.
signature algorithm is specified by the Hierarchical Host Identity The signature algorithm is specified by the Hierarchical Host
Tags (HHIT) Suite ID of the DET. Identity Tags (HHIT) Suite ID of the DET.
When using this structure, the UA is minimally self-endorsing its When using this structure, the UA is minimally self-endorsing its
DET. The HI of the UA DET can be looked up by mechanisms described DET. The HI of the UA DET can be looked up by mechanisms described
in [DRIP-REG] or by extracting it from a Broadcast Endorsement (see in [DRIP-REG] or by extracting it from a Broadcast Endorsement (see
Sections 4.2 and 6.3). Sections 4.2 and 6.3).
4.2. DRIP Link 4.2. DRIP Link
This SAM Type is used to transmit Broadcast Endorsements. For This SAM Type (Figure 5) is used to transmit Broadcast Endorsements.
example, the BE: HDA, UA is sent (see Section 6.3) as a DRIP Link For example, the BE: HDA, UA is sent (see Section 6.3) as a DRIP Link
message. message.
DRIP Link is important as its contents are used to provide trust in DRIP Link is important as its contents are used to provide trust in
the DET/HI pair that the UA is currently broadcasting. This message the DET/HI pair that the UA is currently broadcasting. This message
does not require Internet connectivity to perform signature does not require Internet connectivity to perform signature
verification of the contents when the DIME DET/HI is in the verification of the contents when the DIME DET/HI is in the
Observer's cache. It also provides the UA HI, when it is filled with Observer's cache. It also provides the UA HI, when it is filled with
a BE: HDA, UA, so that connectivity is not required when performing a BE: HDA, UA, so that connectivity is not required when performing
signature verification of other DRIP Authentication Messages. signature verification of other DRIP Authentication Messages.
skipping to change at line 731 skipping to change at line 720
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
Figure 5: Broadcast Endorsement / DRIP Link Figure 5: Broadcast Endorsement / DRIP Link
VNB Timestamp by Parent: (4 octets) _VNB Timestamp by Parent_: (4 octets)
See Section 3.2.4.3. Set by Parent Entity. See Section 3.2.4.3. Set by Parent Entity.
VNA Timestamp by Parent: (4 octets) _VNA Timestamp by Parent_: (4 octets)
See Section 3.2.4.3. Set by Parent Entity. See Section 3.2.4.3. Set by Parent Entity.
DET of Child: (16 octets) _DET of Child_: (16 octets)
DRIP Entity Tag of Child Entity. DRIP Entity Tag of Child Entity.
HI of Child: (32 octets) _HI of Child_: (32 octets)
Host Identity of Child Entity. Host Identity of Child Entity.
DET of Parent: (16 octets) _DET of Parent_: (16 octets)
DRIP Entity Tag of Parent Entity in DIME Hierarchy. DRIP Entity Tag of Parent Entity in DIME Hierarchy.
Signature by Parent: (64 octets) _Signature by Parent_: (64 octets)
Signature over concatenation of preceding fields (VNB, VNA, DET of Signature over concatenation of preceding fields (_VNB_, _VNA_,
Child, HI of Child, and DET of Parent) using the keypair of the _DET of Child_, _HI of Child_, and _DET of Parent_) using the
Parent DET. keypair of the Parent DET.
This DRIP Authentication Message is used in conjunction with other This DRIP Authentication Message is used in conjunction with other
DRIP SAM Types (such as the Manifest or the Wrapper) that contain DRIP SAM Types (such as the Manifest or the Wrapper) that contain
data (e.g., the ASTM Location/Vector Message, Message Type 0x2) that data (e.g., the ASTM Location/Vector Message, Message Type 0x2) that
is guaranteed to be unique, unpredictable, and easily cross-checked is guaranteed to be unique, unpredictable, and easily cross-checked
by the receiving device. by the receiving device.
A hash of the final link (BE: HDA on UA) in the Broadcast Endorsement A hash of the final link (BE: HDA on UA) in the Broadcast Endorsement
chain MUST be included in each DRIP Manifest (Section 4.4). chain MUST be included in each DRIP Manifest (Section 4.4).
Note: The Endorsement that proves a DET is registered MUST come from
its immediate parent in the registration hierarchy, e.g., a DRIP
Identity Management Entity (DIME) [DRIP-REG]. In the definitive
hierarchy, the parent of the UA is its HHIT Domain Authority (HDA),
the parent of an HDA is its Registered Assigning Authority (RAA),
etc. It is also assumed that all DRIP-aware entities use a DET as
their identifier during interactions with other DRIP-aware entities.
4.3. DRIP Wrapper 4.3. DRIP Wrapper
This SAM Type is used to wrap and sign over a list of other [F3411] This SAM Type is used to wrap and sign over a list of other [F3411]
Broadcast RID messages. Broadcast RID messages.
The Evidence field of the UA-Signed Evidence Structure (Section 4.1) The _Evidence_ field of the _UA-Signed Evidence Structure_
is populated with up to four ASTM Messages [F3411] in a contiguous (Section 4.1) is populated with up to four ASTM Messages [F3411] in a
octet sequence. Only ASTM Message Types 0x0, 0x1, 0x3, 0x4, and 0x5 contiguous octet sequence. Only ASTM Message Types 0x0, 0x1, 0x3,
are allowed and must be in Message Type order as defined by [F3411]. 0x4, and 0x5 are allowed and must be in Message Type order as defined
These messages MUST include the Message Type and Protocol Version by [F3411]. These messages MUST include the Message Type and
octet and MUST NOT include the Message Counter octet (thus are fixed Protocol Version octet and MUST NOT include the Message Counter octet
at 25 octets in length). (thus are fixed at 25 octets in length).
4.3.1. Wrapped Count and Format Validation 4.3.1. Wrapped Count and Format Validation
When decoding a DRIP Wrapper on a receiver, a calculation of the When decoding a DRIP Wrapper on a receiver, a calculation of the
number of messages wrapped and a validation MUST be performed by number of messages wrapped and a validation MUST be performed by
using the number of octets (defined as wrapperLength) between the VNA using the number of octets (defined as wrapperLength) between the
Timestamp by UA and the UA DET as shown in Figure 6. _VNA Timestamp by UA_ and the _UA DET_ as shown in Figure 6.
<CODE BEGINS> <CODE BEGINS>
if (wrapperLength MOD 25) != 0 { if (wrapperLength MOD 25) != 0 {
return DECODE_FAILURE; return DECODE_FAILURE;
} }
wrappedCount = wrapperLength / 25; wrappedCount = wrapperLength / 25;
if (wrappedCount == 0) { if (wrappedCount == 0) {
// DECODE_SUCCESS; treat as DRIP Wrapper over extended transport // DECODE_SUCCESS; treat as DRIP Wrapper over extended transport
} }
else if (wrappedCount > 4) { else if (wrappedCount > 4) {
return DECODE_FAILURE; return DECODE_FAILURE;
} else { } else {
// DECODE_SUCCESS; treat as standard DRIP Wrapper // DECODE_SUCCESS; treat as standard DRIP Wrapper
} }
<CODE ENDS> <CODE ENDS>
Figure 6: Pseudocode for Wrapper Validation and Number of Figure 6: Pseudocode for Wrapper Validation and Number of
Messages calculation Messages Calculation
4.3.2. Wrapper over Extended Transports 4.3.2. Wrapper over Extended Transports
When using Extended Transports, an optimization to DRIP Wrapper can When using Extended Transports, an optimization to DRIP Wrapper can
be made to sign over co-located data in an ASTM Message Pack (Message be made to sign over co-located data in an ASTM Message Pack (Message
Type 0xF). Type 0xF).
To perform this optimization, the UA-Signed Evidence Structure is To perform this optimization, the _UA-Signed Evidence Structure_ is
filled with the ASTM Messages to be in the ASTM Message Pack, the filled with the ASTM Messages to be in the ASTM Message Pack, the
signature is generated, and then the Evidence field is cleared, signature is generated, and then the _Evidence_ field is cleared,
leaving the encoded form shown in Figure 7. leaving the encoded form shown in Figure 7.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| VNB Timestamp by UA | | VNB Timestamp by UA |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| VNA Timestamp by UA | | VNA Timestamp by UA |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| | | |
skipping to change at line 850 skipping to change at line 847
| | | |
| | | |
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
Figure 7: DRIP Wrapper over Extended Transports Figure 7: DRIP Wrapper over Extended Transports
To verify the signature, the receiver MUST concatenate all the To verify the signature, the receiver MUST concatenate all the
messages in the Message Pack (excluding the Authentication Message messages in the Message Pack (excluding the Authentication Message
found in the same Message Pack) in ASTM Message Type order and set found in the same Message Pack) in ASTM Message Type order and set
the Evidence field of the UA-Signed Evidence Structure before the _Evidence_ field of the _UA-Signed Evidence Structure_ before
performing signature verification. performing signature verification.
The functionality of a Wrapper in this form is equivalent to Message The functionality of a Wrapper in this form is equivalent to Message
Set Signature (Authentication Type 0x3) when running over Extended Set Signature (Authentication Type 0x3) when running over Extended
Transports. The Wrapper provides the same format but over both Transports. The Wrapper provides the same format but over both
Extended and Legacy Transports, which allows the transports to be Extended and Legacy Transports, which allows the transports to be
similar. Message Set Signature also implies using the ASTM validator similar. Message Set Signature also implies using the ASTM validator
system architecture, which depends on Internet connectivity for system architecture, which depends on Internet connectivity for
verification that the receiver may not have at the time an verification that the receiver may not have at the time an
Authentication Message is received. This is something the Wrapper, Authentication Message is received. This is something the Wrapper,
skipping to change at line 892 skipping to change at line 889
Wrapper (Section 4.3.3) and greatly reduce overhead. Wrapper (Section 4.3.3) and greatly reduce overhead.
Observers MUST hash all received ASTM Messages and cross-check them Observers MUST hash all received ASTM Messages and cross-check them
against hashes in received Manifests. against hashes in received Manifests.
Judicious use of a Manifest enables an entire Broadcast RID message Judicious use of a Manifest enables an entire Broadcast RID message
stream to be strongly authenticated with less than 100% overhead stream to be strongly authenticated with less than 100% overhead
relative to a completely unauthenticated message stream (see relative to a completely unauthenticated message stream (see
Section 6.3 and Appendix B). Section 6.3 and Appendix B).
The Evidence field of the UA-Signed Evidence Structure (Section 4.1) The _Evidence_ field of the _UA-Signed Evidence Structure_
is populated with 8-octet hashes of [F3411] Broadcast RID messages (Section 4.1) is populated with 8-octet hashes of [F3411] Broadcast
(up to 11) and three special hashes (Section 4.4.2). All of these RID messages (up to 11) and three special hashes (Section 4.4.2).
hashes MUST be concatenated to form a contiguous octet sequence in All of these hashes MUST be concatenated to form a contiguous octet
the Evidence field. It is RECOMMENDED that the maximum number of sequence in the _Evidence_ field. It is RECOMMENDED that the maximum
ASTM Message Hashes used be 10 (see Appendix B.1.1.2). number of ASTM Message Hashes used be 10 (see Appendix B.1.1.2).
The Previous Manifest Hash, Current Manifest Hash, and DRIP Link (BE: The _Previous Manifest Hash_, _Current Manifest Hash_, and _DRIP Link
HDA, UA) Hash MUST always come before the ASTM Message Hashes as seen (BE: HDA, UA) Hash_ MUST always come before the _ASTM Message Hashes_
in Figure 8. as seen in Figure 8.
An Observer MUST use the Manifest to verify each ASTM Message hashed An Observer MUST use the Manifest to verify each ASTM Message hashed
therein that it has previously received. It can do this without therein that it has previously received. It can do this without
having received them all. A Manifest SHOULD typically encompass a having received them all. A Manifest SHOULD typically encompass a
single transmission cycle of messages being sent; see Section 6.4 and single transmission cycle of messages being sent; see Section 6.4 and
Appendix B. Appendix B.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
skipping to change at line 930 skipping to change at line 927
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| | | |
. . . .
. ASTM Message Hashes . . ASTM Message Hashes .
. . . .
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
Figure 8: DRIP Manifest Evidence Structure Figure 8: DRIP Manifest Evidence Structure
Previous Manifest Hash: (8 octets) _Previous Manifest Hash_: (8 octets)
Hash of the previously sent Manifest Message. Hash of the previously sent Manifest Message.
Current Manifest Hash: (8 octets) _Current Manifest Hash_: (8 octets)
Hash of the current Manifest Message. Hash of the current Manifest Message.
DRIP Link (BE: HDA, UA): (8 octets) _DRIP Link (BE: HDA, UA)_: (8 octets)
Hash of the DRIP Link Authentication Message carrying BE: HDA, UA Hash of the DRIP Link Authentication Message carrying BE: HDA, UA
(see Section 4.2). (see Section 4.2).
ASTM Message Hash: (8 octets) _ASTM Message Hash_: (8 octets)
Hash of a single full ASTM Message using hash operations described Hash of a single full ASTM Message using hash operations described
in Section 4.4.3. in Section 4.4.3.
4.4.1. Hash Count and Format Validation 4.4.1. Hash Count and Format Validation
When decoding a DRIP Manifest on a receiver, a calculation of the When decoding a DRIP Manifest on a receiver, a calculation of the
number of hashes and a validation can be performed by using the number of hashes and a validation can be performed by using the
number of octets between the UA DET and the VNB Timestamp by UA number of octets between the _UA DET_ and the _VNB Timestamp by UA_
(defined as manifestLength) such as shown in Figure 9. (defined as manifestLength) such as shown in Figure 9.
<CODE BEGINS> <CODE BEGINS>
if (manifestLength MOD 8) != 0 { if (manifestLength MOD 8) != 0 {
return DECODE_FAILURE return DECODE_FAILURE
} }
hashCount = (manifestLength / 8) - 3; hashCount = (manifestLength / 8) - 3;
<CODE ENDS> <CODE ENDS>
Figure 9: Pseudocode for Manifest Sanity Check and Number of Figure 9: Pseudocode for Manifest Sanity Check and Number of
Hashes Calculation Hashes Calculation
4.4.2. Manifest Ledger Hashes 4.4.2. Manifest Ledger Hashes
The following three special hashes are included in all Manifests: The following three special hashes are included in all Manifests:
* the Previous Manifest Hash links to the previous Manifest. * the _Previous Manifest Hash_ links to the previous Manifest.
* the Current Manifest Hash is of the Manifest in which it appears. * the _Current Manifest Hash_ is of the Manifest in which it
appears.
* the DRIP Link (BE: HDA, UA) Hash ties the endorsed UA key to the * the _DRIP Link (BE: HDA, UA) Hash_ ties the endorsed UA key to the
Manifest chain. Manifest chain.
The Previous and Current hashes act as a ledger of provenance for the The Previous and Current hashes act as a ledger of provenance for the
Manifest chain, which should be traced back if the Observer and UA Manifest chain, which should be traced back if the Observer and UA
were within Broadcast RID wireless range of each other for an were within Broadcast RID wireless range of each other for an
extended period of time. extended period of time.
The DRIP Link (BE: HDA, UA) is included so there is a direct The _DRIP Link (BE: HDA, UA)_ is included so there is a direct
signature by the UA over the Broadcast Endorsement (see Section 4.2). signature by the UA over the Broadcast Endorsement (see Section 4.2).
Typical operation would expect that the list of ASTM Message Hashes Typical operation would expect that the list of _ASTM Message Hashes_
contain nonce-like data. To enforce a binding between the BE: HDA, contain nonce-like data. To enforce a binding between the BE: HDA,
UA and avoid trivial replay attack vectors (see Section 9.1), at UA and avoid trivial replay attack vectors (see Section 9.1), at
least one ASTM Message Hash MUST be from an [F3411] message that least one _ASTM Message Hash_ MUST be from an [F3411] message that
satisfies the fourth requirement in Section 6.3. satisfies the fourth requirement in Section 6.3.
4.4.3. Hash Algorithms and Operation 4.4.3. Hash Algorithms and Operation
The hash algorithm used for the Manifest is the same hash algorithm The hash algorithm used for the Manifest is the same hash algorithm
used in creation of the DET [RFC9374] that is signing the Manifest. used in creation of the DET [RFC9374] that is signing the Manifest.
This is encoded as part of the DET using the HHIT Suite ID. This is encoded as part of the DET using the HHIT Suite ID.
DETs that use cSHAKE128 [NIST.SP.800-185] compute the hash as DETs that use cSHAKE128 [NIST.SP.800-185] compute the hash as
follows: follows:
cSHAKE128(ASTM Message, 64, "", "Remote ID Auth Hash") cSHAKE128(ASTM Message, 64, "", "Remote ID Auth Hash")
For ORCHID Generation Algorithms (OGAs) other than "5" (EdDSA/ For ORCHID Generation Algorithms (OGAs) other than "5" (EdDSA/
cSHAKE128) [RFC9374], use the construct appropriate for the cSHAKE128) [RFC9374], use the construct appropriate for the
associated hash. For example, the hash for "2" (ECDSA/SHA-384) is associated hash. For example, the hash for "2" (ECDSA/SHA-384) is
computed as follows: computed as follows:
Ltrunc( SHA-384( ASTM Message | "Remote ID Auth Hash" ), 8 ) Ltrunc( SHA-384( ASTM Message | "Remote ID Auth Hash" ), 8 )
When building the list of hashes, the Previous Manifest Hash is known When building the list of hashes, the _Previous Manifest Hash_ is
from the previous Manifest. For the first built Manifest, this value known from the previous Manifest. For the first built Manifest, this
is filled with a random nonce. The Current Manifest Hash is null value is filled with a random nonce. The _Current Manifest Hash_ is
filled while ASTM Messages are hashed and fill the ASTM Message null filled while ASTM Messages are hashed and fill the _ASTM Message
Hashes field. When all messages are hashed, the Current Manifest Hashes_ field. When all messages are hashed, the _Current Manifest
Hash is computed over the Previous Manifest Hash, Current Manifest Hash_ is computed over the _Previous Manifest Hash_, _Current
Hash (null filled), and ASTM Message Hashes. This hash value Manifest Hash_ (null filled), and _ASTM Message Hashes_. This hash
replaces the null-filled Current Manifest Hash and becomes the value replaces the null-filled _Current Manifest Hash_ and becomes
Previous Manifest Hash for the next Manifest. the _Previous Manifest Hash_ for the next Manifest.
4.4.3.1. Legacy Transport Hashing 4.4.3.1. Legacy Transport Hashing
Under this transport, DRIP hashes the full ASTM Message being sent Under this transport, DRIP hashes the full ASTM Message being sent
over the Bluetooth Advertising frame. This is the 25-octet object over the Bluetooth Advertising frame. This is the 25-octet object
that starts with the Message Type and Protocol Version octet along that starts with the Message Type and Protocol Version octet along
with the 24 octets of message data. The hash MUST NOT include the with the 24 octets of message data. The hash MUST NOT include the
Message Counter octet. Message Counter octet.
For paged ASTM Messages (currently only Authentication Messages), all For paged ASTM Messages (currently only Authentication Messages), all
skipping to change at line 1037 skipping to change at line 1035
hashed as one object. hashed as one object.
4.4.3.2. Extended Transport Hashing 4.4.3.2. Extended Transport Hashing
Under this transport, DRIP hashes the full ASTM Message Pack (Message Under this transport, DRIP hashes the full ASTM Message Pack (Message
Type 0xF) regardless of its content. The hash MUST NOT include the Type 0xF) regardless of its content. The hash MUST NOT include the
Message Counter octet. Message Counter octet.
4.5. DRIP Frame 4.5. DRIP Frame
This SAM Type is defined to enable use of the UA-Signed Evidence This SAM Type is defined to enable use of the _UA-Signed Evidence
Structure (Section 4.1) in the future beyond the previously defined Structure_ (Section 4.1) in the future beyond the previously defined
formats (Wrapper and Manifest) by the inclusion of a single octet to formats (Wrapper and Manifest) by the inclusion of a single octet to
signal the format of Evidence data (up to 111 octets). signal the format of _Evidence_ data (up to 111 octets).
The content format of Frame Evidence Data is not defined in this The content format of _Frame Evidence Data_ is not defined in this
document. Other specifications MUST define the contents and register document. Other specifications MUST define the contents and register
for a Frame Type. At the time of publication (2024), there are no for a _Frame Type_. At the time of publication (2024), there are no
defined Frame Types; only an Experimental range has been defined. defined Frame Types; only an Experimental range has been defined.
Observers MUST check the signature of the structure (Section 4.1) per Observers MUST check the signature of the structure (Section 4.1) per
Section 3.1.2.2 and MAY, if the specification of Frame Type is known, Section 3.1.2.2 and MAY, if the specification of _Frame Type_ is
parse the content in Frame Evidence Data. known, parse the content in _Frame Evidence Data_.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| Frame Type | | | Frame Type | |
+---------------+ . +---------------+ .
. Frame Evidence Data . . Frame Evidence Data .
. . . .
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
Figure 10: DRIP Frame Figure 10: DRIP Frame
Frame Type: (1 octet) _Frame Type_: (1 octet)
As shown in Figure 10, the Frame Type takes the first octet, which As shown in Figure 10, the _Frame Type_ takes the first octet,
leaves 111 octets available for Frame Evidence Data. See which leaves 111 octets available for _Frame Evidence Data_. See
Section 8.1 for Frame Type allocations. Section 8.1 for Frame Type allocations.
5. Forward Error Correction 5. Forward Error Correction
For Broadcast RID, FEC is provided by the lower layers in Extended For Broadcast RID, FEC is provided by the lower layers in Extended
Transports. The Bluetooth 4.x Legacy Transport does not support FEC, Transports. The Bluetooth 4.x Legacy Transport does not support FEC,
so the following application-level scheme is used with DRIP so the following application-level scheme is used with DRIP
Authentication to add some FEC. When sending data over a medium that Authentication to add some FEC. When sending data over a medium that
does not have underlying FEC, for example Bluetooth 4.x, this section does not have underlying FEC, for example Bluetooth 4.x, this section
MUST be used. MUST be used.
skipping to change at line 1094 skipping to change at line 1092
all page data of an Authentication Message. This allows the all page data of an Authentication Message. This allows the
correction of a single erased page in an Authentication Message. If correction of a single erased page in an Authentication Message. If
more than a single page is missing, then handling of an incomplete more than a single page is missing, then handling of an incomplete
Authentication Message is determined by higher layers. Authentication Message is determined by higher layers.
Other FEC schemes, to protect more than a single page of an Other FEC schemes, to protect more than a single page of an
Authentication Message or multiple [F3411] Messages, are left for Authentication Message or multiple [F3411] Messages, are left for
future standardization if operational experience proves it necessary future standardization if operational experience proves it necessary
and/or practical. and/or practical.
The data added during FEC is not included in the Authentication Data The data added during FEC is not included in the _Authentication Data
/ Signature, but instead in the Additional Data field of Figure 2. / Signature_, but instead in the _Additional Data_ field of Figure 2.
This may cause the Authentication Message to exceed 9 pages, up to a This may cause the Authentication Message to exceed 9 pages, up to a
maximum of 16 pages. maximum of 16 pages.
5.1. Encoding 5.1. Encoding
When encoding, two things are REQUIRED: When encoding, two things are REQUIRED:
1. The FEC data MUST start on a new Authentication Page. To do 1. The FEC data MUST start on a new Authentication Page. To do
this, the results of parity encoding MUST be placed in the this, the results of parity encoding MUST be placed in the
Additional Data field of Figure 2 with null padding before it to _Additional Data_ field of Figure 2 with null padding before it
line up with the next page. The Additional Data Length field to line up with the next page. The _Additional Data Length_
MUST be set to number of padding octets + number of parity field MUST be set to number of padding octets + number of parity
octets. octets.
2. The Last Page Index field (in Page 0) MUST be incremented from 2. The _Last Page Index_ field (in Page 0) MUST be incremented from
what it would have been without FEC by the number of pages what it would have been without FEC by the number of pages
required for the Additional Data Length field, null padding, and required for the _Additional Data Length_ field, null padding,
FEC. and FEC.
To generate the parity, a simple XOR operation using the previous To generate the parity, a simple XOR operation using the previous
parity page and current page is used. Only the 23-octet parity page and current page is used. Only the 23-octet
Authentication Payload field of Figure 1 is used in the XOR _Authentication Payload_ field of Figure 1 is used in the XOR
operations. For Page 0, a 23-octet null pad is used for the previous operations. For Page 0, a 23-octet null pad is used for the previous
parity page. parity page.
Figure 11 shows an example of the last two pages (out of N) of an Figure 11 shows an example of the last two pages (out of N) of an
Authentication Message using DRIP Single Page FEC. The Additional Authentication Message using DRIP Single Page FEC. The _Additional
Data Length is set to 33, as there are always 23 octets of FEC data Data Length_ is set to 33, as there are always 23 octets of FEC data
and there are 10 octets of padding in this example to line it up into and there are 10 octets of padding in this example to line it up into
Page N. Page N.
Page N-1: Page N-1:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| Page Header | | | Page Header | |
+---------------+ | +---------------+ |
| Authentication Data / Signature | | Authentication Data / Signature |
skipping to change at line 1160 skipping to change at line 1158
| | | |
| | | |
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
Figure 11: Example Single Page FEC Encoding Figure 11: Example Single Page FEC Encoding
5.2. Decoding 5.2. Decoding
Frame decoding is independent of the transmit media. However, the Frame decoding is independent of the transmit media. However, the
decoding process can determine from the first Authentication page decoding process can determine from the first Authentication Page
that there may be a Bluetooth 4.x FEC page at the end. The decoding that there may be a Bluetooth 4.x FEC page at the end. The decoding
process MUST test for the presence of FEC and apply it as follows. process MUST test for the presence of FEC and apply it as follows.
To determine if FEC has been used, a check of the Last Page Index is To determine if FEC has been used, a check of the _Last Page Index_
performed. In general, if the Last Page Index field is one greater is performed. In general, if the _Last Page Index_ field is one
than that necessary to hold Length octets of Authentication Data, greater than that necessary to hold _Length_ octets of Authentication
then FEC has been used. Note that if Length octets are exhausted Data, then FEC has been used. Note that if _Length_ octets are
exactly at the end of an Authentication Page, the Additional Data exhausted exactly at the end of an Authentication Page, the
Length field will occupy the first octet of the following page. The _Additional Data Length_ field will occupy the first octet of the
remainder of this page will be null padded under DRIP to align the following page. The remainder of this page will be null padded under
FEC to its own page. In this case, the Last Page Index will have DRIP to align the FEC to its own page. In this case, the _Last Page
been incremented once for initializing the Additional Data Length Index_ will have been incremented once for initializing the
field and once for the FEC page, for a total of two additional pages, _Additional Data Length_ field and once for the FEC page, for a total
as in the last row of Table 5. of two additional pages, as in the last row of Table 5.
To decode FEC in DRIP, a rolling XOR is used on each Authentication To decode FEC in DRIP, a rolling XOR is used on each _Authentication
Page received in the current Authentication Message. A Message Page_ received in the current Authentication Message. A Message
Counter, outside of the ASTM Message but specified in [F3411], is Counter, outside of the ASTM Message but specified in [F3411], is
used to signal a different Authentication Message and to correlate used to signal a different Authentication Message and to correlate
pages to messages. This Message Counter is only a single octet in pages to messages. This Message Counter is only a single octet in
length, so it will roll over (to 0x00) after reaching its maximum length, so it will roll over (to 0x00) after reaching its maximum
value (0xFF). If only a single page is missing in the Authentication value (0xFF). If only a single page is missing in the Authentication
Message the resulting parity octets should be the data of the erased Message the resulting parity octets should be the data of the erased
page. page.
Authentication Page 0 contains various important fields, only located Authentication Page 0 contains various important fields, only located
on that page, that help decode the full ASTM Authentication Message. on that page, that help decode the full ASTM Authentication Message.
If Page 0 has been reconstructed, the Last Page Index and Length If Page 0 has been reconstructed, the _Last Page Index_ and _Length_
fields MUST be validated by DRIP. The pseudocode in Figure 12 can be fields MUST be validated by DRIP. The pseudocode in Figure 12 can be
used for both checks. used for both checks.
<CODE BEGINS> <CODE BEGINS>
function decode_check(auth_pages[], decoded_lpi, decoded_length) { function decode_check(auth_pages[], decoded_lpi, decoded_length) {
// check decoded_lpi does not exceed maximum value // check decoded_lpi does not exceed maximum value
if (decoded_lpi >= 16) { if (decoded_lpi >= 16) {
return DECODE_FAILURE return DECODE_FAILURE
} }
skipping to change at line 1222 skipping to change at line 1220
} }
// check that byte directly after last auth byte is null // check that byte directly after last auth byte is null
if (auth_data[last_auth_byte + 1] equals null) { if (auth_data[last_auth_byte + 1] equals null) {
return DECODE_FAILURE return DECODE_FAILURE
} }
// we set our presumed Additional Data Length (ADL) // we set our presumed Additional Data Length (ADL)
presumed_adl = auth_data[last_auth_byte + 1] presumed_adl = auth_data[last_auth_byte + 1]
// use the presumed ADL to calculate a presumed // use the presumed ADL to calculate a presumed
//Last Page Index (LPI, a field defined in <xref target="F3411"/>) //Last Page Index (LPI, a field defined in [F3411])
presumed_lpi = (presumed_adl + decoded_length - 17) / 23 presumed_lpi = (presumed_adl + decoded_length - 17) / 23
// check that presumed LPI and decoded LPI match // check that presumed LPI and decoded LPI match
if (presumed_lpi not equal decoded_lpi) { if (presumed_lpi not equal decoded_lpi) {
return DECODE_FAILURE return DECODE_FAILURE
} }
return DECODE_SUCCESS return DECODE_SUCCESS
} }
<CODE ENDS> <CODE ENDS>
Figure 12: Pseudocode for Decode Checks Figure 12: Pseudocode for Decode Checks
5.3. FEC Limitations 5.3. FEC Limitations
The worst-case scenario is when the Authentication Data / Signature The worst-case scenario is when the _Authentication Data / Signature_
ends perfectly on a page boundary (Page N-1). This means the ends perfectly on a page boundary (Page N-1). This means the
Additional Data Length would start the next page (Page N) and have 22 _Additional Data Length_ would start the next page (Page N) and have
octets worth of null padding to align the FEC to begin at the start 22 octets worth of null padding to align the FEC to begin at the
of the next page (Page N+1). In this scenario, an entire page (Page start of the next page (Page N+1). In this scenario, an entire page
N) is being wasted just to carry the Additional Data Length. (Page N) is being wasted just to carry the _Additional Data Length_.
6. Requirements and Recommendations 6. Requirements and Recommendations
6.1. Legacy Transports 6.1. Legacy Transports
Under DRIP, the goal is to bring reliable receipt of the paged Under DRIP, the goal is to bring reliable receipt of the paged
Authentication Message using Legacy Transports. FEC (Section 5) MUST Authentication Message using Legacy Transports. FEC (Section 5) MUST
be used, per mandated RID rules (for example, the US FAA RID Rules be used, per mandated RID rules (for example, the US FAA RID Rules
[FAA-14CFR]), when using Legacy Transports (such as Bluetooth 4.x). [FAA-14CFR]), when using Legacy Transports (such as Bluetooth 4.x).
skipping to change at line 1501 skipping to change at line 1499
Successful signature verification, using that public key, of a Successful signature verification, using that public key, of a
Wrapper (Section 4.3) or Manifest (Section 4.4) message, Wrapper (Section 4.3) or Manifest (Section 4.4) message,
authenticating content that is nonce-like, provides trust that the authenticating content that is nonce-like, provides trust that the
sender actually possesses the corresponding private key. sender actually possesses the corresponding private key.
The term "nonce-like" describes data that is unique, changes The term "nonce-like" describes data that is unique, changes
frequently, is not accurately predictable long in advance, and is frequently, is not accurately predictable long in advance, and is
easily validated (i.e., can be checked quickly at low computational easily validated (i.e., can be checked quickly at low computational
cost using readily available data) by the Observer. A Location/ cost using readily available data) by the Observer. A Location/
Vector Message is an obvious choice. This is described in Vector Message is an obvious choice. This is described in
Section 6.3 (requirement 4) and Section 3.1.2.2. The Location/Vector Section 3.1.2.2 and Section 6.3 (requirement 4). The Location/Vector
Message [F3411] reporting precise UA position and velocity at a Message [F3411] reporting precise UA position and velocity at a
precise and very recent time is to be checked by the Observer against precise and very recent time is to be checked by the Observer against
visual observations of the UA within RF. Thus, Visual Line of Sight visual observations of the UA within RF. Thus, Visual Line of Sight
is typically the recommended form of this data. For specification of is typically the recommended form of this data. For specification of
the foregoing, see Sections 3.1.2 and 6.4.2. the foregoing, see Sections 3.1.2 and 6.4.2.
Messages that pass signature verification with trusted keys could Messages that pass signature verification with trusted keys could
still be replays if they contain only static information (e.g., still be replays if they contain only static information (e.g.,
Broadcast Endorsements (Section 4.2), [F3411] Basic ID or [F3411] Broadcast Endorsements (Section 4.2), [F3411] Basic ID or [F3411]
Operator ID), or information that cannot be readily validated (e.g., Operator ID), or information that cannot be readily validated (e.g.,
skipping to change at line 1574 skipping to change at line 1572
frames* (manifest frame count + base frame count). frames* (manifest frame count + base frame count).
9.3. VNA Timestamp Offsets for DRIP Authentication Formats 9.3. VNA Timestamp Offsets for DRIP Authentication Formats
Note the discussion of VNA Timestamp offsets here is in the context Note the discussion of VNA Timestamp offsets here is in the context
of the DRIP Wrapper (Section 4.3), DRIP Manifest (Section 4.4), and of the DRIP Wrapper (Section 4.3), DRIP Manifest (Section 4.4), and
DRIP Frame (Section 4.5). For DRIP Link (Section 4.2), these offsets DRIP Frame (Section 4.5). For DRIP Link (Section 4.2), these offsets
are set by the DIME and have their own set of considerations in are set by the DIME and have their own set of considerations in
[DRIP-REG]. [DRIP-REG].
The offset of the VNA Timestamp by UA is one that needs careful The offset of the _VNA Timestamp by UA_ is one that needs careful
consideration for any implementation. The offset should be shorter consideration for any implementation. The offset should be shorter
than any given flight duration (typically less than an hour) but be than any given flight duration (typically less than an hour) but be
long enough to be received and processed by Observers (larger than a long enough to be received and processed by Observers (larger than a
few seconds). It is recommended that 3-5 minutes should be few seconds). It is recommended that 3-5 minutes should be
sufficient to serve this purpose in any scenario, but it is not sufficient to serve this purpose in any scenario, but it is not
limited by design. limited by design.
9.4. DNS Security in DRIP 9.4. DNS Security in DRIP
As stated in Section 3.1 specification of particular DNS security As stated in Section 3.1 specification of particular DNS security
skipping to change at line 1687 skipping to change at line 1685
constraints (such as saturation of limited bandwidth). As such, constraints (such as saturation of limited bandwidth). As such,
there are scenarios where part of the key-chain may be unavailable at there are scenarios where part of the key-chain may be unavailable at
the moment a full Authentication Message is received and processed. the moment a full Authentication Message is received and processed.
The intent of this informative appendix is to recommend a way to The intent of this informative appendix is to recommend a way to
classify these various states and convey it to the user through classify these various states and convey it to the user through
colors and state names/text. These states can apply to either a colors and state names/text. These states can apply to either a
single Authentication Message, a DET (and its associated public key), single Authentication Message, a DET (and its associated public key),
and/or a sender. and/or a sender.
The table below briefly describes each state and recommends an Table 4 briefly describes each state and recommends an associated
associated color. color.
+==============+========+===================================+ +==============+========+===================================+
| State | Color | Details | | State | Color | Details |
+==============+========+===================================+ +==============+========+===================================+
| None | Black | No Authentication has been or is | | None | Black | No Authentication has been or is |
| | | being received (as yet) | | | | being received (as yet) |
+--------------+--------+-----------------------------------+ +--------------+--------+-----------------------------------+
| Partial | Gray | Authentication being received but | | Partial | Gray | Authentication being received but |
| | | missing pages | | | | missing pages |
+--------------+--------+-----------------------------------+ +--------------+--------+-----------------------------------+
skipping to change at line 1733 skipping to change at line 1731
Table 4: Authentication State Names, Colors, and Descriptions Table 4: Authentication State Names, Colors, and Descriptions
A.1. None: Black A.1. None: Black
The default state where authentication information has not yet been The default state where authentication information has not yet been
received and is not currently being received. received and is not currently being received.
A.2. Partial: Gray A.2. Partial: Gray
A pending state where authentication pages are being received, but a A pending state where Authentication Pages are being received, but a
full Authentication Message has yet to be compiled. full Authentication Message has yet to be compiled.
A.3. Unsupported: Brown A.3. Unsupported: Brown
A state wherein authentication data is being or has been received but A state wherein authentication data is being or has been received but
cannot be used, as the Authentication Type or SAM Type is not cannot be used, as the Authentication Type or SAM Type is not
supported by the Observer. supported by the Observer.
A.4. Unverifiable: Yellow A.4. Unverifiable: Yellow
skipping to change at line 1808 skipping to change at line 1806
transition from either of those states upon mixed results on the transition from either of those states upon mixed results on the
requirement of Section 6.4.2. requirement of Section 6.4.2.
Appendix B. Operational Recommendation Analysis Appendix B. Operational Recommendation Analysis
The recommendations in Section 6.4 may seem heavy-handed and The recommendations in Section 6.4 may seem heavy-handed and
specific. This informative appendix lays out the math and specific. This informative appendix lays out the math and
assumptions made that resulted in those recommendations and provides assumptions made that resulted in those recommendations and provides
an example. an example.
In many jurisdictions, the required ASTM Messages to be transmitted In all jurisdictions known to the authors of this document as of its
every second are: Basic ID (0x0), Location/Vector (0x1), and System publication (2024), at least the following ASTM Messages are required
(0x4). Typical implementations will most likely send at a higher to be transmitted at least once per second:
rate (2x sets per cycle) resulting in 6 frames sent per cycle.
Transmitting this set of messages more than once a second is not
discouraged, but awareness is needed to avoid congesting the RF
spectrum, causing further issues.
Informational Note: In Europe, transmission of the Operator ID * Basic ID (0x1)
Message (0x5) is also required. In Japan, transmission of two Basic
IDs (0x0), a Location/Vector (0x1), and an Authentication (0x2) are * Location (0x2)
required. Self ID (0x3) transmission is optional but can carry
Emergency Status information. * System (0x4)
Europe also requires:
* Operator ID Message (0x5)
Japan requires not one but two Basic ID messages:
* one carrying a manufacturer assigned serial number
* one carrying a CAA assigned registration number
Japan also requires:
* Authentication (0x2) using their own unique scheme
In all jurisdictions, one further message is optional, but highly
recommended for carriage of additional information on the nature of
the emergency if the Emergency value is sent in the Operational
Status field of the Location/Vector Message:
* Self ID (0x3)
To improve the likelihood of successful timely receipt of regulator
required RID data elements, most implementations send at a higher
rate, whether by repeating the same messages in the same one second
interval, or updating message content and sending messages more
frequently than once per second. Excessive sending rate, however,
could congest the RF spectrum, leading to collisions and counter-
intuitively actually reducing the likelihood of timely receipt of RID
data.
B.1. Page Counts vs Frame Counts B.1. Page Counts vs Frame Counts
There are two formulas to determine the number of Authentication There are two formulas to determine the number of Authentication
Pages required. The following formula is for Wrapper: Pages required. The following formula is for Wrapper:
<CODE BEGINS> <CODE BEGINS>
wrapper_struct_size = 89 + (25 * num_astm_messages) wrapper_struct_size = 89 + (25 * num_astm_messages)
wrapper_page_count = ceiling((wrapper_struct_size - 17) / 23) + 1 wrapper_page_count = ceiling((wrapper_struct_size - 17) / 23) + 1
<CODE ENDS> <CODE ENDS>
skipping to change at line 1899 skipping to change at line 1923
five slots; thus it can authenticate up to four ASTM Messages co- five slots; thus it can authenticate up to four ASTM Messages co-
located in the same Message Pack. located in the same Message Pack.
B.1.1.2. Eleven ASTM Messages B.1.1.2. Eleven ASTM Messages
Eleven ASTM Messages (see Table 5) is where a Manifest with FEC Eleven ASTM Messages (see Table 5) is where a Manifest with FEC
invokes the situation mentioned in Section 5.3. invokes the situation mentioned in Section 5.3.
Eleven is the maximum number of ASTM Message Hashes that can be Eleven is the maximum number of ASTM Message Hashes that can be
supported resulting in 14 total hashes. This completely fills the supported resulting in 14 total hashes. This completely fills the
Evidence field of the UA-Signed Evidence Structure making its total _Evidence_ field of the _UA-Signed Evidence Structure_ making its
size 200 octets. This fits on exactly 9 Authentication Pages ((201 - total size 200 octets. This fits on exactly 9 Authentication Pages
17) / 23 == 8), so when the ADL is added, it is placed on the next ((201 - 17) / 23 == 8), so when the ADL is added, it is placed on the
page (Page 10). Per rule 1 in Section 5.1, this means that all of next page (Page 10). Per rule 1 in Section 5.1, this means that all
Page 10 is null padded (expect the ADL octet) and FEC data fills Page of Page 10 is null padded (expect the ADL octet) and FEC data fills
11, resulting in a plus-two page count when FEC is applied. Page 11, resulting in a plus-two page count when FEC is applied.
This drives the recommendation is Section 4.4 to only use up to 10 This drives the recommendation is Section 4.4 to only use up to 10
ASTM Message Hashes, not 11. ASTM Message Hashes, not 11.
B.2. Full Authentication Example B.2. Full Authentication Example
This example is focused on showing that 100% of ASTM Messages can be This example (Figure 13) is focused on showing that 100% of ASTM
authenticated over Legacy Transports with up to 125% overhead in Messages can be authenticated over Legacy Transports with up to 125%
Authentication Pages. Extended Transports are not shown in this overhead in Authentication Pages. Extended Transports are not shown
example, because, for those, Authentication with DRIP is achieved in this example, because, for those, Authentication with DRIP is
using Extended Wrapper (Section 4.3.2). Two ASTM Message Packs are achieved using Extended Wrapper (Section 4.3.2). Two ASTM Message
sent in a given cycle: one containing up to four ASTM Messages and an Packs are sent in a given cycle: one containing up to four ASTM
Extended Wrapper (authenticating the pack), and one containing a Link Messages and an Extended Wrapper (authenticating the pack), and one
message with a Broadcast Endorsement and up to two other ASTM containing a Link message with a Broadcast Endorsement and up to two
Messages. other ASTM Messages.
This example transmit scheme covers and meets every known regulatory This example transmit scheme covers and meets every known regulatory
case enabling manufacturers to use the same firmware worldwide. case enabling manufacturers to use the same firmware worldwide.
+------------------------------------------------------+ +------------------------------------------------------+
| Frame Slots | | Frame Slots |
| 00 - 04 | 05 - 07 | 08 - 16 | 17 | | 00 - 04 | 05 - 07 | 08 - 16 | 17 |
+-------------------+---------------+---------+--------+ +-------------------+---------------+---------+--------+
| {A|B|C|D},V,S,I,O | {A|B|C|D},V,S | M[0,8] | L/W[0] | | {A|B|C|D},V,S,I,O | {A|B|C|D},V,S | M[0,8] | L/W[0] |
+-------------------+---------------+---------+--------+ +-------------------+---------------+---------+--------+
skipping to change at line 2069 skipping to change at line 2093
LLC for early prototyping to find holes in earlier drafts of this LLC for early prototyping to find holes in earlier drafts of this
specification. specification.
* Carsten Bormann for the simple approach of using bit-column-wise * Carsten Bormann for the simple approach of using bit-column-wise
parity for erasure (dropped frame) FEC. parity for erasure (dropped frame) FEC.
* Soren Friis for pointing out that Wi-Fi implementations would not * Soren Friis for pointing out that Wi-Fi implementations would not
always give access to the MAC Address, as was originally used in always give access to the MAC Address, as was originally used in
calculation of the hashes for DRIP Manifest. Also, for confirming calculation of the hashes for DRIP Manifest. Also, for confirming
that Message Packs (0xF) can only carry up to 9 ASTM frames worth that Message Packs (0xF) can only carry up to 9 ASTM frames worth
of data (9 Authentication pages) of data (9 Authentication Pages).
* Gabriel Cox (chair of the working group that produced [F3411]) for * Gabriel Cox (chair of the working group that produced [F3411]) for
reviewing the specification for the SAM Type request as the ASTM reviewing the specification for the SAM Type request as the ASTM
Designated Expert. Designated Expert.
* Mohamed Boucadair (Document Shepherd) for his many patches and * Mohamed Boucadair (Document Shepherd) for his many patches and
comments. comments.
* Eric Vyncke (DRIP AD) for his guidance regarding the document's * Eric Vyncke (DRIP AD) for his guidance regarding the document's
path to publication. path to publication.
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