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docName="draft-ietf-drip-auth-49"
number="9575"
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<front> <front>
<title abbrev="DRIP Auth Formats">DRIP Entity Tag Authentication Formats &am <title abbrev="DRIP Auth Formats">DRIP Entity Tag Authentication Formats and
p; Protocols for Broadcast Remote ID</title> Protocols for Broadcast Remote Identification</title>
<seriesInfo name="Internet-Draft" value="draft-ietf-drip-auth-49"/> <seriesInfo name="RFC" value="9575"/>
<author initials="A." surname="Wiethuechter" fullname="Adam Wiethuechter" ro le="editor"> <author initials="A." surname="Wiethuechter" fullname="Adam Wiethuechter" ro le="editor">
<organization>AX Enterprize, LLC</organization> <organization>AX Enterprize, LLC</organization>
<address> <address>
<postal> <postal>
<street>4947 Commercial Drive</street> <street>4947 Commercial Drive</street>
<city>Yorkville</city> <city>Yorkville</city>
<region>NY</region> <region>NY</region>
<code>13495</code> <code>13495</code>
<country>USA</country> <country>United States of America</country>
</postal> </postal>
<email>adam.wiethuechter@axenterprize.com</email> <email>adam.wiethuechter@axenterprize.com</email>
</address> </address>
</author> </author>
<author initials="S." surname="Card" fullname="Stuart Card"> <author initials="S." surname="Card" fullname="Stuart Card">
<organization>AX Enterprize, LLC</organization> <organization>AX Enterprize, LLC</organization>
<address> <address>
<postal> <postal>
<street>4947 Commercial Drive</street> <street>4947 Commercial Drive</street>
<city>Yorkville</city> <city>Yorkville</city>
<region>NY</region> <region>NY</region>
<code>13495</code> <code>13495</code>
<country>USA</country> <country>United States of America</country>
</postal> </postal>
<email>stu.card@axenterprize.com</email> <email>stu.card@axenterprize.com</email>
</address> </address>
</author> </author>
<author initials="R." surname="Moskowitz" fullname="Robert Moskowitz"> <author initials="R." surname="Moskowitz" fullname="Robert Moskowitz">
<organization>HTT Consulting</organization> <organization>HTT Consulting</organization>
<address> <address>
<postal> <postal>
<street/> <street/>
<city>Oak Park</city> <city>Oak Park</city>
<region>MI</region> <region>MI</region>
<code>48237</code> <code>48237</code>
<country>USA</country> <country>United States of America</country>
</postal> </postal>
<email>rgm@labs.htt-consult.com</email> <email>rgm@labs.htt-consult.com</email>
</address> </address>
</author> </author>
<date year="2024" month="February" day="21"/> <date year="2024" month="May"/>
<area>Internet</area>
<workgroup>DRIP Working Group</workgroup> <area>INT</area>
<keyword>Internet-Draft</keyword> <workgroup>drip</workgroup>
<keyword>drone</keyword>
<keyword>UAS</keyword>
<keyword>Broadcast RID</keyword>
<keyword>trustworthy remote identification</keyword>
<keyword>anti-spoofing</keyword>
<abstract> <abstract>
<t>The Drone Remote Identification Protocol (DRIP), plus trust policies an d periodic access to registries, augments Unmanned Aircraft System (UAS) Remote Identification (RID), enabling local real time assessment of trustworthiness of received RID messages and observed UAS, even by Observers lacking Internet acces s. This document defines DRIP message types and formats to be sent in Broadcast RID Authentication Messages to verify that attached and recent detached messages were signed by the registered owner of the DRIP Entity Tag (DET) claimed.</t> <t>The Drone Remote Identification Protocol (DRIP), plus trust policies an d periodic access to registries, augments Unmanned Aircraft System (UAS) Remote Identification (RID), enabling local real-time assessment of trustworthiness of received RID messages and observed UAS, even by Observers lacking Internet acces s. This document defines DRIP message types and formats to be sent in Broadcast RID Authentication Messages to verify that attached and recently detached messag es were signed by the registered owner of the DRIP Entity Tag (DET) claimed.</t>
</abstract> </abstract>
</front> </front>
<middle> <middle>
<section anchor="introduction" numbered="true" toc="default"> <section anchor="introduction" numbered="true" toc="default">
<name>Introduction</name> <name>Introduction</name>
<t>The initial regulations (e.g., <xref target="FAA-14CFR" format="default <t>The initial regulations (e.g., <xref target="FAA-14CFR" format="default
"/>) and standards (e.g., <xref target="F3411" format="default"/>) for Unmanned "/>) and standards (e.g., <xref target="F3411" format="default"/>) for Unmanned
Aircraft (UA) Systems (UAS) Remote Identification and tracking (RID) do not addr Aircraft Systems (UAS) Remote Identification (RID) and tracking do not address
ess trust. However, this is a requirement that needs to be addressed for various trust. However, this is a requirement that needs to be addressed for various dif
different parties that have a stake in the safe operation of National Airspace ferent parties that have a stake in the safe operation of National Airspace Syst
Systems (NAS). Drone Remote ID Protocol's (DRIP's) goal is to specify how RID ca ems (NAS). Drone Remote ID Protocol's (DRIP's) goal is to specify how RID can be
n be made trustworthy and available in both Internet and local-only connected sc made trustworthy and available in both Internet and local-only connected scenar
enarios, especially in emergency situations.</t> ios, especially in emergency situations.</t>
<t>UAS often operate in a volatile environment. Small UA offer little capa <t>UAS often operate in a volatile environment. A small Unmanned Aircraft
city for computation and communication. UAS RID must also be accessible with ubi (UA) offers little capacity for computation and communication. UAS RID must also
quitous and inexpensive devices without modification. This limits options. Most be accessible with ubiquitous and inexpensive devices without modification. Thi
current small UAS are IoT devices even if not typically thought of as such. Thus s limits options. Most current small UAS are Internet of Things (IoT) devices ev
many IoT considerations apply here. Some DRIP work, currently strongly scoped t en if they are not typically thought of as such. Thus many IoT considerations ap
o UAS RID, is likely to be applicable to some other IoT use-cases.</t> ply here. Some DRIP work, currently strongly scoped to UAS RID, is likely to be
<t>Generally, two communication schemes for UAS RID are considered: Broadc applicable to some other IoT use cases.</t>
ast and Network. This document focuses on adding trust to Broadcast RID (Section
3.2 of <xref target="RFC9153" format="default"/> and Section 1.2.2 of <xref tar <t>Generally, two communication schemes for UAS RID are considered: Broadc
get="RFC9434" format="default"/>). As defined in <xref target="F3411" format="de ast and Network. This document focuses on adding trust to Broadcast RID (<xref t
fault"/> and outlined in <xref target="RFC9153" format="default"/> and <xref tar arget="RFC9153" sectionFormat="of" section="3.2"/> and <xref target="RFC9434" se
get="RFC9434" format="default"/>, Broadcast RID is a one-way RF transmission of ctionFormat="of" section="1.2.2"/>). As defined in <xref target="F3411" format="
MAC layer messages over Bluetooth or Wi-Fi.</t> default"/> and outlined in <xref target="RFC9153" format="default"/> and <xref t
<t>Senders can make any claims the RID message formats allow. Observers ha arget="RFC9434" format="default"/>, Broadcast RID is a one-way Radio Frequency (
ve no standardized means to assess the trustworthiness of message content, nor v RF) transmission of Media Access Control (MAC) layer messages over Bluetooth or
erify whether the messages were sent by the UA identified therein, nor confirm t Wi-Fi.</t>
hat the UA identified therein is the one they are visually observing. Indeed, Ob <t>Senders can make any claims the RID message formats allow. Observers ha
servers have no way to detect whether the messages were sent by a UA, or spoofed ve no standardized means to assess the trustworthiness of message content, nor v
by some other transmitter (e.g., a laptop or smartphone) anywhere in direct wir erify whether the messages were sent by the UA identified therein, nor confirm t
eless broadcast range. Authentication is the primary strategy for mitigating thi hat the UA identified therein is the one they are visually observing. Indeed, Ob
s issue.</t> servers have no way to detect whether the messages were sent by a UA or spoofed
by some other transmitter (e.g., a laptop or smartphone) anywhere in direct wire
less broadcast range. Authentication is the primary strategy for mitigating this
issue.</t>
<section anchor="drip-entity-tag-det-authentication-goals-for-broadcast-ri d" numbered="true" toc="default"> <section anchor="drip-entity-tag-det-authentication-goals-for-broadcast-ri d" numbered="true" toc="default">
<name>DRIP Entity Tag (DET) Authentication Goals for Broadcast RID</name > <name>DRIP Entity Tag (DET) Authentication Goals for Broadcast RID</name >
<t>ASTM <xref target="F3411" format="default"/> Authentication Messages <t>ASTM <xref target="F3411" format="default"/> Authentication Messages
(Message Type 0x2), when used with DRIP Entity Tag (DET) <xref target="RFC9374" (Message Type 0x2), when used with DET-based formats <xref target="RFC9374" form
format="default"/> based formats, enable a high level of trust that the content at="default"/>, enable a high level of trust that the content of other ASTM Mess
of other ASTM Messages was generated by their claimed registered source. These m ages was generated by their claimed registered source. These messages are design
essages are designed to provide the Observers with trustworthy and immediately a ed to provide the Observers with trustworthy and immediately actionable informat
ctionable information. <xref target="auth-state-diagrams" format="default"/> pro ion. <xref target="auth-state-diagrams" format="default"/> provides a high-level
vides a high-level overview of the various states of trustworthiness that may be overview of the various states of trustworthiness that may be used along with t
used along with these formats.</t> hese formats.</t>
<t>This authentication approach also provides some error correction (<xr ef target="fec-details" format="default"/>) as mandated by the United States (US ) Federal Aviation Administration (FAA) <xref target="FAA-14CFR" format="default "/>, which is missing from <xref target="F3411" format="default"/> over Legacy T ransports (Bluetooth 4.x).</t> <t>This authentication approach also provides some error correction (<xr ef target="fec-details" format="default"/>) as mandated by the United States (US ) Federal Aviation Administration (FAA) <xref target="FAA-14CFR" format="default "/>, which is missing from <xref target="F3411" format="default"/> over Legacy T ransports (Bluetooth 4.x).</t>
<t>These DRIP enhancements to ASTM's <xref target="F3411" format="defaul <t>These DRIP enhancements to ASTM's specification for RID and tracking
t"/> further support the important use case of Observers who may be offline at t <xref target="F3411" format="default"/> further support the important use case o
he time of observation.</t> f Observers who may be offline at the time of observation.</t>
<t>A summary of DRIP requirements <xref target="RFC9153" format="default <t><xref target="req-sum" format="default"/> summarizes the DRIP require
"/> addressed herein is provided in <xref target="req-sum" format="default"/>.</ ments <xref target="RFC9153" format="default"/> addressed herein.</t>
t> <!-- [rfced] Please review whether any of the notes in this document should be
<ul empty="true" spacing="normal"> in the <aside> element. It is defined as "a container for content that is
<li>Note: The Endorsement (used in <xref target="drip-link" format="de semantically less important or tangential to the content that surrounds
fault"/>) that proves that a DET is registered MUST come from its immediate pare it" (https://authors.ietf.org/en/rfcxml-vocabulary#aside).
nt in the registration hierarchy, e.g., a DRIP Identity Management Entity (DIME)
<xref target="drip-registries" format="default"/>. In the definitive hierarchy, 2 May 2024: Wait for further guidance from authors.
the parent of the UA is its HHIT Domain Authority (HDA), the parent of an HDA i -->
s its Registered Assigning Authority (RAA), etc. It is also assumed that all DRI
P-aware entities use a DET as their identifier during interactions with other DR <t>Note: The Endorsement (used in <xref target="drip-link" format="def
IP-aware entities.</li> ault"/>) that proves that a DET is registered <bcp14>MUST</bcp14> come from its
</ul> immediate parent in the registration hierarchy, e.g., a DRIP Identity Management
Entity (DIME) <xref target="I-D.ietf-drip-registries" format="default"/>. In th
e 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 al
so assumed that all DRIP-aware entities use a DET as their identifier during int
eractions with other DRIP-aware entities.</t>
</section> </section>
</section> </section>
<section anchor="terminology" numbered="true" toc="default"> <section anchor="terminology" numbered="true" toc="default">
<name>Terminology</name> <name>Terminology</name>
<section anchor="required-terminology" numbered="true" toc="default"> <section anchor="required-terminology" numbered="true" toc="default">
<name>Required Terminology</name> <name>Required Terminology</name>
<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", " <t>
SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" i The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>",
n this document are to be interpreted as described in BCP 14 <xref target="RFC21 "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL NOT</bcp14>
19" format="default"/> <xref target="RFC8174" format="default"/> when, and only ",
when, they appear in all capitals, as shown here.</t> "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>",
"<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
"<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are to
be
interpreted as described in BCP&nbsp;14 <xref target="RFC2119"/> <xref
target="RFC8174"/> when, and only when, they appear in all capitals, as
shown here.
</t>
</section> </section>
<section anchor="definitions" numbered="true" toc="default"> <section anchor="definitions" numbered="true" toc="default">
<name>Definitions</name> <name>Definitions</name>
<t>This document makes use of the terms (CAA, Observer, USS, UTM, etc.) defined in <xref target="RFC9153" format="default"/>. Other terms (such as DIME) are from <xref target="RFC9434" format="default"/>, while others (HI, DET, RAA, HDA, etc.) are from <xref target="RFC9374" format="default"/>.</t> <t>This document makes use of the terms (CAA, Observer, USS, UTM, etc.) defined in <xref target="RFC9153" format="default"/>. Other terms (such as DIME) are from <xref target="RFC9434" format="default"/>, while others (HI, DET, RAA, HDA, etc.) are from <xref target="RFC9374" format="default"/>.</t>
<t>In addition, the following terms are defined for this document:</t> <t>In addition, the following terms are defined for this document:</t>
<t>Extended Transports:</t> <dl>
<ul empty="true" spacing="normal"> <dt>Extended Transports:</dt>
<li>Use of extended advertisements (Bluetooth 5.x), service info (Wi-F <dd>Use of extended advertisements (Bluetooth 5.x), service info
i Neighbor Awareness Networking (NAN)), or IEEE 802.11 Beacons with vendor speci (Wi-Fi Neighbor Awareness Networking (NAN)), or IEEE 802.11 Beacons
fic information element as specified in <xref target="F3411" format="default"/>. with the vendor-specific information element as specified in <xref
Must use ASTM Message Pack (Message Type 0xF).</li> target="F3411" format="default"/>. Must use ASTM Message Pack (Message
</ul> Type 0xF).</dd>
<t>Legacy Transports:</t> <dt>Legacy Transports:</dt>
<ul empty="true" spacing="normal"> <dd>Use of broadcast frames (Bluetooth 4.x) as specified in <xref
<li>Use of broadcast frames (Bluetooth 4.x) as specified in <xref targ target="F3411" format="default"/>.</dd>
et="F3411" format="default"/>.</li> <dt>Manifest:</dt>
</ul> <dd>An immutable list of items being transported (in this specific
<t>Manifest:</t> case over wireless communication).</dd>
<ul empty="true" spacing="normal"> </dl>
<li>an immutable list of items being transported (in this specific cas
e over wireless communication).</li>
</ul>
</section> </section>
</section> </section>
<section anchor="uas-rid-authentication-background-procedures" numbered="tru e" toc="default"> <section anchor="uas-rid-authentication-background-procedures" numbered="tru e" toc="default">
<name>UAS RID Authentication Background &amp; Procedures</name> <name>UAS RID Authentication Background and Procedures</name>
<section anchor="protocol-desc" numbered="true" toc="default"> <section anchor="protocol-desc" numbered="true" toc="default">
<name>DRIP Authentication Protocol Description</name> <name>DRIP Authentication Protocol Description</name>
<t><xref target="F3411" format="default"/> defines Authentication Messag <t><xref target="F3411" format="default"/> defines Authentication Messag
e framing only. It does not define authentication formats or methods. It explici e framing only. It does not define authentication formats or methods. It explici
tly anticipates several signature options but does not fully define those. Annex tly anticipates several signature options but does not fully define those. Annex
A1 of <xref target="F3411" format="default"/> defines a Broadcast Authenticatio A1 of <xref target="F3411" format="default"/> defines a Broadcast Authenticatio
n Verifier Service, which has a heavy reliance on Observer real-time connectivit n Verifier Service, which has a heavy reliance on Observer real-time connectivit
y to the Internet. Fortunately, <xref target="F3411" format="default"/> also all y to the Internet. Fortunately, <xref target="F3411" format="default"/> also all
ows third party standard Authentication Types using Type 5 Specific Authenticati ows third-party standard Authentication Types using the Type 0x5 Specific Authen
on Method (SAM), several of which DRIP defines herein.</t> tication Method (SAM), several of which DRIP defines herein.</t>
<t>The standardization of specific formats to support the DRIP requireme
nts in UAS RID for trustworthy communications over Broadcast RID is an important <t>The standardization of specific formats to support the DRIP requireme
part of the chain of trust for a UAS ID. Per Section 5 of <xref target="RFC9434 nts in UAS RID for trustworthy communications over Broadcast RID is an important
" format="default"/>, Authentication formats are needed to relay information for part of the chain of trust for a UAS ID. Per <xref target="RFC9434" sectionForm
Observers to determine trust. No existing formats (defined in <xref target="F34 at="of" section="5"/>, Authentication formats are needed to relay information fo
11" format="default"/> or other organizations leveraging this feature) provide t r Observers to determine trust. No existing formats (defined in <xref target="F3
he functionality to satisfy this goal resulting in the work reflected in this do 411" format="default"/> or other organizations leveraging this feature) provide
cument.</t> functionality to satisfy this goal, resulting in the work reflected in this doc
ument.</t>
<section anchor="auth-dns" numbered="true" toc="default"> <section anchor="auth-dns" numbered="true" toc="default">
<name>Usage of DNS</name> <name>Usage of DNS</name>
<t>Like most aviation matters, the overall objectives here are securit <t>Like most aviation matters, the overall objectives here are securit
y and ultimately safety oriented. Since DRIP depends on DNS for some of its func y and ultimately safety oriented. Since DRIP depends on DNS for some of its func
tions, DRIP usage of DNS needs to be protected as per best security practices. M tions, DRIP usage of DNS needs to be protected per best security practices. Many
any participating nodes will have limited local processing power and/or poor, lo participating nodes will have limited local processing power and/or poor, low-b
w bandwidth QoS paths. Appropriate and feasible security techniques will be high andwidth QoS paths. Appropriate and feasible security techniques will be highly
ly UAS and Observer situation dependent. Therefore specification of particular D dependent on the UAS and Observer situation. Therefore, specification of particu
NS security options, transports, etc. is outside the scope of this document (see lar DNS security options, transports, etc. is outside the scope of this document
also <xref target="dns-security" format="default"/>).</t> (see also <xref target="dns-security" format="default"/>).</t>
<t>In DRIP Observers MUST validate all signatures received. This requi <t>In DRIP, Observers <bcp14>MUST</bcp14> validate all signatures rece
res the Host Identity (HI) corresponding to a DET <xref target="RFC9374" format= ived. This requires that the Host Identity (HI) correspond to a DET <xref target
"default"/>. HI's MAY be retrieved from a local cache, if present. The local cac ="RFC9374" format="default"/>. HI's <bcp14>MAY</bcp14> be retrieved from a local
he is pre-configured with well knowns HIs (such as those of CAA DIMEs) and furth cache, if present. The local cache is pre-configured with well-known HIs (such
er populated by received Broadcast Endorsements (BEs) (<xref target="dime-attest as those of CAA DIMEs) and is further populated by received Broadcast Endorsemen
ation" format="default"/>) and DNS lookups (when available).</t> ts (BEs) (<xref target="dime-attestation" format="default"/>) and DNS lookups (w
<t>The Observer MUST perform a DNS query, when connectivity allows, to hen available).</t>
obtain an HI not previously known. If a query can not be performed, the message <t>The Observer <bcp14>MUST</bcp14> perform a DNS query, when connecti
SHOULD be cached by the Observer to be validated once the HI is obtained.</t> vity allows, to obtain a previously unknown HI. If a query cannot be performed,
<t>A more comprehensive specification of DRIP's use of DNS is out of s the message <bcp14>SHOULD</bcp14> be cached by the Observer to be validated once
cope for this document and can be found in <xref target="drip-registries" format the HI is obtained.</t>
="default"/>.</t> <t>A more comprehensive specification of DRIP's use of DNS is out of s
cope for this document and can be found in <xref target="I-D.ietf-drip-registrie
s" format="default"/>.</t>
</section> </section>
<section anchor="rid-trust" numbered="true" toc="default"> <section anchor="rid-trust" numbered="true" toc="default">
<name>Providing UAS RID Trust</name> <name>Providing UAS RID Trust</name>
<t>For DRIP, two actions together provide a mechanism for an Observer to trust in UAS RID using Authentication Messages.</t> <t>For DRIP, two actions together provide a mechanism for an Observer to trust in UAS RID using Authentication Messages.</t>
<t>First is the transmission of an entire trust chain via Broadcast En dorsements (<xref target="dime-attestation" format="default"/>). This provides a hierarchy of DIMEs down to and including an individual UA's registration of a c laimed DET and corresponding HI (public key). This alone cannot be trusted as ha ving any relevance to the observed UA because replay attacks are trivial.</t> <t>First is the transmission of an entire trust chain via Broadcast En dorsements (<xref target="dime-attestation" format="default"/>). This provides a hierarchy of DIMEs down to and including an individual UA's registration of a c laimed DET and corresponding HI (public key). This alone cannot be trusted as ha ving any relevance to the observed UA because replay attacks are trivial.</t>
<t>After an Observer has gathered such a complete key trust chain (fro <t>After an Observer has gathered such a complete key trust chain (fro
m pre-configured cache entries, Broadcast Endorsements received over the air and m pre-configured cache entries, Broadcast Endorsements received over the air and
/or DNS lookups) and verified all of its links, that device can trust that claim /or DNS lookups) and verified all of its links, that device can trust that the c
ed DET and corresponding public key are properly registered, but the UA has not laimed DET and corresponding public key are properly registered, but the UA has
yet been proven to possess the corresponding private key.</t> not yet been proven to possess the corresponding private key.</t>
<t>It is necessary for the UA to prove possession by dynamically signi <t>It is necessary for the UA to prove possession by dynamically signi
ng data that is unique and unpredictable but easily verified by the Observer (<x ng data that is unique and unpredictable but easily verified by the Observer (<x
ref target="ua-attestation" format="default"/>). Verification of this signed dat ref target="ua-attestation" format="default"/>). Verification of this signed dat
a MUST be performed by the Observer as part of the received UAS RID information a <bcp14>MUST</bcp14> be performed by the Observer as part of the received UAS R
trust assessment (<xref target="trust-assessment" format="default"/>).</t> ID information trust assessment (<xref target="trust-assessment" format="default
"/>).</t>
<section anchor="dime-attestation" numbered="true" toc="default"> <section anchor="dime-attestation" numbered="true" toc="default">
<name>DIME Endorsements of Subordinate DETs</name> <name>DIME Endorsements of Subordinate DETs</name>
<t>Observers receive DRIP Link Authentication Messages (<xref target <t>Observers receive DRIP Link Authentication Messages (<xref target
="drip-link" format="default"/>) containing Broadcast Endorsements by DIMEs of c ="drip-link" format="default"/>) containing Broadcast Endorsements by DIMEs of c
hild DET registrations. A series of these Endorsements confirms a path through t hild DET registrations. A series of these Endorsements confirms a path through t
he hierarchy, defined in <xref target="drip-registries" format="default"/>, from he hierarchy, defined in <xref target="I-D.ietf-drip-registries" format="default
the DET Prefix Owner all the way to an individual UA DET registration.</t> "/>, from the DET Prefix Owner all the way to an individual UA DET registration.
<ul empty="true" spacing="normal"> </t>
<li>Note: For the remainder of this document <tt>Broadcast Endorse <t>Note: For the remainder of this document, <tt>Broadcast
ment: Parent, Child</tt> will be abbreviated to <tt>BE: Parent, Child</tt>. For Endorsement: Parent, Child</tt> will be abbreviated as <tt>BE:
example <tt>Broadcast Endorsement: RAA, HDA</tt> will be abbreviated to <tt>BE: Parent, Child</tt>. For example, <tt>Broadcast Endorsement: RAA, HDA</
RAA, HDA</tt>.</li> tt> will be abbreviated as <tt>BE: RAA, HDA</tt>.</t>
</ul>
</section> </section>
<section anchor="ua-attestation" numbered="true" toc="default"> <section anchor="ua-attestation" numbered="true" toc="default">
<name>UA Signed Evidence</name> <name>UA-Signed Evidence</name>
<t>To prove possession of the private key associated to the DET, the <t> To prove possession of the private key associated with the DET,
UA MUST send data that is unique and unpredictable but easily validated by the the UA
Observer, that is signed over. The data can be an ASTM Message that fulfills the <bcp14>MUST</bcp14> sign and send data that is unique and unpredictable but ea
requirements to be unpredictable but easily validated. An Observer receives thi sily validated by the Observer. The data can be an ASTM Message that fulfills th
s UA-signed Evidence from DRIP-based Authentication Messages (<xref target="drip e requirements to be unpredictable but easily validated. An Observer receives th
-wrapper" format="default"/> or <xref target="drip-manifest" format="default"/>) is UA-signed Evidence from DRIP-based Authentication Messages (Sections <xref ta
.</t> rget="drip-wrapper" format="counter"/> or <xref target="drip-manifest" format="c
<t>Whether the content is true is a separate question which DRIP can ounter"/>).</t>
not address, but validation performed using observable and/or out of band data ( <t>Whether the content is true is a separate question that DRIP cann
<xref target="reqs" format="default"/>) are possible and encouraged.</t> ot address, but validation performed using observable and/or out-of-band data (<
xref target="reqs" format="default"/>) is possible and encouraged.</t>
</section> </section>
</section> </section>
</section> </section>
<section anchor="auth-message" numbered="true" toc="default"> <section anchor="auth-message" numbered="true" toc="default">
<name>ASTM Authentication Message Framing</name> <name>ASTM Authentication Message Framing</name>
<t>The Authentication Message (Message Type 0x2) is unique in the ASTM < <t>The Authentication Message (Message Type 0x2) is unique in the ASTM
xref target="F3411" format="default"/> Broadcast standard as it is the only mess <xref target="F3411" format="default"/> Broadcast standard, as it is the only me
age that can be larger than the Legacy Transport size. To address this limitatio ssage that can be larger than the Legacy Transport size. To address this limitat
n around transport size, it is defined as a set of "pages", each of which fits i ion around transport size, it is defined as a set of "pages", each of which fits
nto a single Legacy Transport frame. For Extended Transports, pages are still us into a single Legacy Transport frame. For Extended Transports, pages are still
ed but all are in a single frame.</t> used but they are all in a single frame.</t>
<ul empty="true" spacing="normal"> <t>Informational Note: Message Pack (Message Type 0xF) is also
<li>Informational Note: Message Pack (Message Type 0xF) is also larger larger than the Legacy Transport size but is limited for use only on
than the Legacy Transport size but is limited for use only on Extended Transpor Extended Transports where it can be supported.</t>
ts where is can be supported.</li> <t>The following subsections are a brief overview of the Authentication
</ul> Message format defined in <xref target="F3411" format="default"/> for better con
<t>The following sub-sections are a brief overview of the Authentication text on how DRIP Authentication fills and uses various fields already defined by
Message format defined in <xref target="F3411" format="default"/> for better co ASTM <xref target="F3411" format="default"/>.</t>
ntext on how DRIP Authentication fills and uses various fields already defined b
y ASTM <xref target="F3411" format="default"/>.</t>
<section anchor="auth-page" numbered="true" toc="default"> <section anchor="auth-page" numbered="true" toc="default">
<name>Authentication Page</name> <name>Authentication Page</name>
<t>This document leverages Authentication Type 0x5, Specific Authentic ation Method (SAM), as the principal authentication container, defining a set of SAM Types in <xref target="drip-authentication-formats" format="default"/>. Aut hentication Type is encoded in every Authentication Page in the <tt>Page Header< /tt>. The SAM Type is defined as a field in the <tt>Authentication Payload</tt> (see <xref target="sam-data" format="default"/>).</t> <t>This document leverages Authentication Type 0x5 (Specific Authentic ation Method (SAM)) as the principal authentication container, defining a set of SAM Types in <xref target="drip-authentication-formats" format="default"/>. Aut hentication Type is encoded in every Authentication Page in the <em>Page Header< /em>. The SAM Type is defined as a field in the <em>Authentication Payload</em> (see <xref target="sam-data" format="default"/>).</t>
<figure anchor="astm-auth-page"> <figure anchor="astm-auth-page">
<name>Standard ASTM Authentication Message Page</name> <name>Standard ASTM Authentication Message Page</name>
<artwork align="center" name="" type="" alt=""><![CDATA[ <artwork align="center" name="" type="" alt=""><![CDATA[
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 |
| | | |
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
]]></artwork> ]]></artwork>
</figure> </figure>
<t>Page Header: (1 octet)</t> <dl><dt>Page Header:</dt><dd><t>(1 octet)</t>
<ul empty="true" spacing="normal"> <t>Authentication Type (4 bits) and Page Number (4 bits)</t></dd>
<li>Authentication Type (4 bits) and Page Number (4 bits)</li>
</ul> <dt>Authentication Payload:</dt><dd><t>(23 octets per page)</t>
<t>Authentication Payload: (23 octets per page)</t> <t>Authentication Payload, including headers. Null padded. See
<ul empty="true" spacing="normal"> <xref target="auth-payload" format="default"/>.</t></dd>
<li>Authentication Payload, including headers. Null padded. See <xre </dl>
f target="auth-payload" format="default"/>.</li> <t>The Authentication Message is structured as a set of pages per <xre
</ul> f target="astm-auth-page" format="default"/>. There is a technical maximum of 16
<t>The Authentication Message is structured as a set of pages per <xre pages (indexed 0 to 15) that can be sent for a single Authentication Message, w
f target="astm-auth-page" format="default"/>. There is a technical maximum of 16 ith each page carrying a maximum 23-octet <tt>Authentication Payload</tt>. See <
pages (indexed 0 to 15) that can be sent for a single Authentication Message, w xref target="drip-restrictions" format="default"/> for more details. Over Legacy
ith each page carrying a maximum 23 octet <tt>Authentication Payload</tt>. See < Transports, these messages are "fragmented", with each page sent in a separate
xref target="drip-restrictions" format="default"/> for more details. Over Legacy Legacy Transport frame.</t>
Transports, these messages are "fragmented", with each page sent in a separate
Legacy Transport frame.</t>
<t>Either as a single Authentication Message or a set of fragmented Au thentication Message Pages, the structure is further wrapped by outer ASTM frami ng and the specific link framing.</t> <t>Either as a single Authentication Message or a set of fragmented Au thentication Message Pages, the structure is further wrapped by outer ASTM frami ng and the specific link framing.</t>
</section> </section>
<section anchor="auth-payload" numbered="true" toc="default"> <section anchor="auth-payload" numbered="true" toc="default">
<name>Authentication Payload Field</name> <name>Authentication Payload Field</name>
<t><xref target="astm-auth" format="default"/> is the source data view of the data fields found in the Authentication Message as defined by <xref targ et="F3411" format="default"/>. This data is placed into <xref target="astm-auth- page" format="default"/>'s <tt>Authentication Payload</tt>, spanning multiple <t t>Authentication Pages</tt>.</t> <t><xref target="astm-auth" format="default"/> is the source data view of the data fields found in the Authentication Message as defined by <xref targ et="F3411" format="default"/>. This data is placed into the <tt>Authentication P ayload</tt> shown in <xref target="astm-auth-page" format="default"/>, which spa ns multiple <tt>Authentication Pages</tt>.</t>
<figure anchor="astm-auth"> <figure anchor="astm-auth">
<name>ASTM Authentication Message Fields</name> <name>ASTM Authentication Message Fields</name>
<artwork align="center" name="" type="" alt=""><![CDATA[ <artwork align="center" name="" type="" alt=""><![CDATA[
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 |
| +---------------+---------------+ | +---------------+---------------+
| | | | | |
+---------------+---------------+ | +---------------+---------------+ |
skipping to change at line 200 skipping to change at line 244
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| ADL | | | ADL | |
+---------------+ | +---------------+ |
. . . .
. Additional Data . . Additional Data .
. . . .
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
]]></artwork> ]]></artwork>
</figure> </figure>
<t>Authentication Headers: (6 octets)</t> <dl><dt>Authentication Headers:</dt><dd><t>(6 octets)</t>
<ul empty="true" spacing="normal"> <t>As defined in <xref target="F3411" format="default"/>.</t></dd>
<li>As defined in <xref target="F3411" format="default"/>.</li> <dt>Authentication Data / Signature:</dt><dd><t>(0 to 255 octets)</t>
</ul> <t>Opaque authentication data. The length of this payload is
<t>Authentication Data / Signature: (0 to 255 octets)</t> known through a field in the <tt>Authentication Headers</tt>
<ul empty="true" spacing="normal"> (defined in <xref target="F3411" format="default"/>).</t></dd>
<li>Opaque authentication data. The length of this payload is known <dt>Additional Data Length (ADL):</dt><dd><t>(1 octet - unsigned)</t>
through a field in the <tt>Authentication Headers</tt> (defined in <xref target= <t>Length in octets of <tt>Additional Data</tt>. The
"F3411" format="default"/>).</li> value of <tt>ADL</tt> is calculated as the minimum of <tt>361 -
</ul> Authentication Data / Signature Length</tt> and <tt>255</tt>. Only
<t>Additional Data Length (ADL): (1 octet - unsigned)</t> present with <tt>Additional Data</tt>.</t></dd>
<ul empty="true" spacing="normal"> <dt>Additional Data:</dt><dd><t>(<tt>ADL</tt> octets)</t>
<li>Length in octets of <tt>Additional Data</tt>. The value of <tt>A <t>Data that follows the <tt>Authentication Data /
DL</tt> is calculated as the minimum of <tt>361 - Authentication Data / Signatur Signature</tt> but is not considered part of the <tt>Authentication
e Length</tt> and <tt>255</tt>. Only present with <tt>Additional Data</tt>.</li> Data</tt>, and thus is not covered by a signature. For DRIP, this fiel
</ul> d
<t>Additional Data: (<tt>ADL</tt> octets)</t> is used to carry Forward Error Correction (FEC) generated by
<ul empty="true" spacing="normal"> transmitters and parsed by receivers as defined in <xref
<li>Data that follows the <tt>Authentication Data / Signature</tt> b target="fec-details" format="default"/>.</t></dd></dl>
ut is not considered part of the <tt>Authentication Data</tt> thus is not covere
d by a signature. For DRIP, this field is used to carry Forward Error Correction
(FEC) generated by transmitters and parsed by receivers as defined in <xref tar
get="fec-details" format="default"/>.</li>
</ul>
</section> </section>
<section anchor="specific-authentication-method-sam" numbered="true" toc ="default"> <section anchor="specific-authentication-method-sam" numbered="true" toc ="default">
<name>Specific Authentication Method (SAM)</name> <name>Specific Authentication Method (SAM)</name>
<section anchor="sam-data" numbered="true" toc="default"> <section anchor="sam-data" numbered="true" toc="default">
<name>SAM Data Format</name> <name>SAM Data Format</name>
<t><xref target="sam-frame" format="default"/> is the general format to hold authentication data when using SAM and is placed inside the <tt>Authent ication Data/Signature</tt> field in <xref target="astm-auth" format="default"/> .</t> <t><xref target="sam-frame" format="default"/> is the general format to hold authentication data when using SAM and is placed inside the <tt>Authent ication Data / Signature</tt> field in <xref target="astm-auth" format="default" />.</t>
<figure anchor="sam-frame"> <figure anchor="sam-frame">
<name>SAM Data Format</name> <name>SAM Data Format</name>
<artwork align="center" name="" type="" alt=""><![CDATA[ <artwork align="center" name="" type="" alt=""><![CDATA[
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 .
. . . .
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
]]></artwork> ]]></artwork>
</figure> </figure>
<t>SAM Type: (1 octet)</t>
<ul empty="true" spacing="normal"> <dl><dt>SAM Type:</dt><dd><t>(1 octet)</t>
<li>The following SAM Types are allocated to DRIP:</li> <t>The following SAM Types are allocated to DRIP:</t>
</ul>
<table align="center"> <table align="center">
<name>DRIP SAM Types</name> <name>DRIP SAM Types</name>
<thead> <thead>
<tr> <tr>
<th align="left">SAM Type</th> <th align="left">SAM Type</th>
<th align="left">Description</th> <th align="left">Description</th>
</tr> </tr>
</thead> </thead>
<tbody> <tbody>
<tr> <tr>
skipping to change at line 268 skipping to change at line 313
<tr> <tr>
<td align="left">0x03</td> <td align="left">0x03</td>
<td align="left">DRIP Manifest (<xref target="drip-manifest" f ormat="default"/>)</td> <td align="left">DRIP Manifest (<xref target="drip-manifest" f ormat="default"/>)</td>
</tr> </tr>
<tr> <tr>
<td align="left">0x04</td> <td align="left">0x04</td>
<td align="left">DRIP Frame (<xref target="drip-frame" format= "default"/>)</td> <td align="left">DRIP Frame (<xref target="drip-frame" format= "default"/>)</td>
</tr> </tr>
</tbody> </tbody>
</table> </table>
<ul empty="true" spacing="normal"> </dd></dl>
<li>Note: ASTM International is the owner of these code points as <t>Note: ASTM International is the owner of these code points as t
they are defined in <xref target="F3411" format="default"/>. In accordance with hey are defined in <xref target="F3411" format="default"/>. In accordance with A
Annex 5 of the ASTM's <xref target="F3411" format="default"/>, the International nnex 5 of <xref target="F3411" format="default"/>, the International Civil Aviat
Civil Aviation Organization (ICAO) has been selected by ASTM as the registrar t ion Organization (ICAO) has been selected by ASTM as the registrar to manage all
o manage allocations of these code points. The list of which can be found at <xr ocations of these code points. The list is available at <xref target="ASTM-Remot
ef target="ASTM-Remote-ID" format="default"/>.</li> e-ID" format="default"/>.</t>
</ul>
<t>SAM Authentication Data: (0 to 200 octets)</t> <dl><dt>SAM Authentication Data:</dt><dd><t>(0 to 200 octets)</t>
<ul empty="true" spacing="normal"> <t>Contains opaque authentication data formatted as defined by the p
<li>Contains opaque authentication data formatted as defined by th receding SAM Type.</t></dd></dl>
e preceding SAM Type.</li>
</ul>
</section> </section>
</section> </section>
<section anchor="drip-restrictions" numbered="true" toc="default"> <section anchor="drip-restrictions" numbered="true" toc="default">
<name>ASTM Broadcast RID Constraints</name> <name>ASTM Broadcast RID Constraints</name>
<section anchor="wireless-frame-constraints" numbered="true" toc="defa ult"> <section anchor="wireless-frame-constraints" numbered="true" toc="defa ult">
<name>Wireless Frame Constraints</name> <name>Wireless Frame Constraints</name>
<t>A UA has the option of broadcasting using Bluetooth (4.x and 5.x)
, Wi-Fi NAN, or IEEE 802.11 Beacon, see <xref target="reqs" format="default"/>. <t>A UA has the option to broadcast using Bluetooth (4.x and 5.x), W
With Bluetooth, FAA and other Civil Aviation Authorities (CAA) mandate transmitt i-Fi NAN, or IEEE 802.11 Beacon; see <xref target="reqs" format="default"/>. Wit
ing simultaneously over both 4.x and 5.x. The same application layer information h Bluetooth, FAA and other Civil Aviation Authorities (CAA) mandate transmitting
defined in <xref target="F3411" format="default"/> MUST be transmitted over all simultaneously over both 4.x and 5.x. The same application-layer information de
the physical layer interfaces performing the function of RID. This is because O fined in <xref target="F3411" format="default"/> <bcp14>MUST</bcp14> be transmit
bserver transports may be limited. If an Observer can support multiple transport ted over all the physical-layer interfaces performing RID, because Observer tran
s it should be assumed to use the latest data regardless of the transport receiv sports may be limited.
ed over.</t> If an Observer can
<t>Bluetooth 4.x presents a payload size challenge in that it can on support multiple transports, it <bcp14>SHOULD</bcp14> uses (display, report, e
ly transmit 25 octets of payload per frame while other transports can support la tc.) the latest
rger payloads per frame. However, the <xref target="F3411" format="default"/> me data regardless of the transport over which that data was received.
ssaging framing dictated by Bluetooth 4.x constraints is inherited by <xref targ
et="F3411" format="default"/> over other media.</t> </t>
<t>It should be noted that Extended Transports by definition have Er <t>Bluetooth 4.x presents a payload-size challenge in that it can on
ror Correction built in, unlike Legacy Transports. For Authentication Messages t ly transmit 25 octets of payload per frame, while other transports can support l
his means that over Legacy Transport pages could be not received by Observers re arger payloads per frame. As <xref target="F3411" format="default"/> message fo
sulting in incomplete messages during operation, although the use of DRIP FEC (< rmats are the same for all media,
xref target="fec-details" format="default"/>) reduces the likelihood of this. Au and their framing was designed to fit within these legacy constraints,
thentication Messages sent using Extended Transports do not suffer this issue as Extended Transports cannot send larger messages;
the full message (all pages) are sent using a single Message Pack. Furthermore instead, the Message Pack format encapsulates multiple messages
the use of one-way RF broadcasts prohibits the use of any congestion control or (each of which fits within these legacy constraints).</t>
loss recovery schemes that require ACKs or NACKs.</t> <!-- [rfced] Thank you for the update. It is much more clear, but we wonder whe
ther "incompletely reconstructable" should simply be "incomplete"? Please consi
der the suggested udpate below.
Current:
...
This would result in delivery to the Observer application of incomplete
(typically unusable) messages, so DRIP FEC (Section 5) is specified
to enable recovery of a single lost page and thereby reduce the likelihood
of receiving incompletely reconstructable Authentication Messages.
Perhaps:
...
This would result in delivery of incomplete
(typically unusable) messages to the Observer application.
DRIP FEC (Section 5) is specified
to enable recovery of a single lost page, thereby reducing the likelihood
of receiving Authentication Messages that are incomplete.
-->
<t>By definition Extended Transports provide FEC,
but Legacy Transports lack FEC. Thus over Legacy Transports, paged
Authentication Messages may suffer the loss of one or more pages.
This would result in delivery to the Observer application of incomplete
(typically unusable) messages, so DRIP FEC (<xref target="fec-details" format=
"default"/>) is specified
to enable recovery of a single lost page and thereby reduce the likelihood
of receiving incompletely reconstructable Authentication Messages.
Authentication Messages sent using Extended Transports do not suffer this issue,
as the full message (all pages) is sent using a single Message Pack. Furthermor
e, the use of one-way RF broadcasts prohibits the use of any congestion-control
or loss-recovery schemes that require ACKs or NACKs.</t>
</section> </section>
<section anchor="paged-authentication-message-constraints" numbered="t rue" toc="default"> <section anchor="paged-authentication-message-constraints" numbered="t rue" toc="default">
<name>Paged Authentication Message Constraints</name> <name>Paged Authentication Message Constraints</name>
<t>To keep consistent formatting across the different transports (Le <t>To keep consistent formatting across the different transports (Le
gacy and Extended) and their independent restrictions, the authentication data b gacy and Extended) and their independent restrictions, the authentication data b
eing sent is REQUIRED to fit within the page limit that the most constrained exi eing sent is <bcp14>REQUIRED</bcp14> to fit within the page limit that the most
sting transport can support. Under Broadcast RID, the Extended Transport that ca constrained existing transport can support. Under Broadcast RID, the Extended Tr
n hold the least amount of authentication data is Bluetooth 5.x at 9 pages.</t> ansport that can hold the least amount of authentication data is Bluetooth 5.x a
<t>As such DRIP transmitters are REQUIRED to adhere to the following t 9 pages.</t>
when using the Authentication Message:</t> <t>As such, DRIP transmitters are <bcp14>REQUIRED</bcp14> to adhere
<ol spacing="normal" type="1"><li> to the following when using the Authentication Message:</t>
<tt>Authentication Data / Signature</tt> data MUST fit in the fi <ol spacing="normal" type="1">
rst 9 pages (Page Numbers 0 through 8).</li> <li><tt>Authentication Data / Signature</tt> data
<li>The <tt>Length</tt> field in the <tt>Authentication Headers</t <bcp14>MUST</bcp14> fit in the first 9 pages (Page Numbers 0
t> (which encodes the length in octets of <tt>Authentication Data / Signature</t through 8).</li>
t> only) MUST NOT exceed the value of 201. This includes the SAM Type but exclud <li>The <tt>Length</tt> field in the <tt>Authentication
es <tt>Additional Data</tt>.</li> Headers</tt> (which encodes the length in octets of
<tt>Authentication Data / Signature</tt> only) <bcp14>MUST
NOT</bcp14> exceed the value of 201. This includes the SAM Type
but excludes <tt>Additional Data</tt>.</li>
</ol> </ol>
</section> </section>
<section anchor="astm-timestamps" numbered="true" toc="default"> <section anchor="astm-timestamps" numbered="true" toc="default">
<name>Timestamps</name> <name>Timestamps</name>
<t>In ASTM <xref target="F3411" format="default"/> timestamps are a <t>In ASTM <xref target="F3411" format="default"/>, timestamps are a
Unix-style timestamp with an epoch of <tt>2019-01-01 00:00:00 UTC</tt>. For DRIP Unix-style timestamp with an epoch of <tt>2019-01-01 00:00:00 UTC</tt>. For DRI
this format is adopted for Authentication to keep a common time format in Broad P, this format is adopted for Authentication to keep a common time format in Bro
cast payloads.</t> adcast payloads.</t>
<t>Under DRIP there are two timestamps defined <tt>Valid Not Before <t>Under DRIP, there are two timestamps defined: <tt>Valid Not Befor
(VNB)</tt> and <tt>Valid Not After (VNA)</tt>.</t> e (VNB)</tt> and <tt>Valid Not After (VNA)</tt>.</t>
<t>Valid Not Before (VNB) Timestamp: (4 octets)</t> <dl><dt>Valid Not Before (VNB) Timestamp:</dt><dd><t>(4 octets)</t>
<ul empty="true" spacing="normal"> <t>Timestamp denoting the recommended time at which to start trustin
<li>Timestamp denoting recommended time to start trusting data in. g data. <bcp14>MUST</bcp14> follow the format defined in <xref target="F3411" fo
MUST follow the format defined in <xref target="F3411" format="default"/> as de rmat="default"/> as described above. <bcp14>MUST</bcp14> be set no earlier than
scribed above. MUST be set no earlier than the time the signature (across a give the time the signature (across a given structure) is generated.</t></dd>
n structure) is generated.</li>
</ul> <dt>Valid Not After (VNA) Timestamp:</dt><dd><t>(4 octets)</t>
<t>Valid Not After (VNA) Timestamp: (4 octets)</t> <t>Timestamp denoting the recommended time at which to stop trusting
<ul empty="true" spacing="normal"> data. <bcp14>MUST</bcp14> follow the format defined in <xref target="F3411" for
<li>Timestamp denoting recommended time to stop trusting data. MUS mat="default"/> as described above. Has an additional offset to push a short tim
T follow the format defined in <xref target="F3411" format="default"/> as descri e into the future (relative to <tt>VNB</tt>) to avoid replay attacks. The exact
bed above. Has an additional offset to push a short time into the future (relati offset is not defined in this document. Best practice for identifying an accepta
ve to <tt>VNB</tt>) to avoid replay attacks. The exact offset is not defined in ble offset should be used and should take into consideration the UA environment,
this document. Best practice identifying an acceptable offset should be used tak propagation characteristics of the messages being sent, and clock differences b
ing into consideration the UA environment, and propagation characteristics of th etween the UA and Observers.
e messages being sent, and clock differences between the UA and Observers. A rea For UA signatures in scenarios typical as of 2024, a reasonable offset would b
sonable time would be to set <tt>VNA</tt> 2 minutes after <tt>VNB</tt>.</li> e
</ul> to set <tt>VNA</tt> approximately 2 minutes after <tt>VNB</tt>; see <xref targ
et="operational-proof"/> for examples
that may aid in tuning this value.</t></dd></dl>
</section> </section>
</section> </section>
</section> </section>
</section> </section>
<section anchor="drip-authentication-formats" numbered="true" toc="default"> <section anchor="drip-authentication-formats" numbered="true" toc="default">
<name>DRIP Authentication Formats</name> <name>DRIP Authentication Formats</name>
<t>All formats defined in this section are the content of the <tt>Authenti <t>All formats defined in this section are contained in the <tt>Authentica
cation Data / Signature</tt> field in <xref target="astm-auth" format="default"/ tion Data / Signature</tt> field in <xref target="astm-auth" format="default"/>
> and use the Specific Authentication Method (SAM, Authentication Type 0x5). The and use the Specific Authentication Method (SAM, Authentication Type 0x5). The f
first octet of the <tt>Authentication Data / Signature</tt> of <xref target="as irst octet of the <tt>Authentication Data / Signature</tt> of <xref target="astm
tm-auth" format="default"/> is used to multiplex among these various formats.</t -auth" format="default"/> is used to multiplex among these various formats.</t>
> <t>
<t>When sending data over a medium that does not have underlying FEC, for When sending data over a medium that does not have underlying FEC,
example Legacy Transports, then <xref target="fec-details" format="default"/> MU for example Legacy Transports, then FEC <xref target="fec-details" format="de
ST be used.</t> fault"/> <bcp14>MUST</bcp14> be used.
<t>Examples of Link, Wrapper and Manifest are shown as part of an operatio </t>
nal schedule in <xref target="raw-example" format="default"/>.</t> <t>Examples of Link, Wrapper, and Manifest are shown as part of an operati
onal schedule in <xref target="raw-example" format="default"/>.</t>
<section anchor="bas" numbered="true" toc="default"> <section anchor="bas" numbered="true" toc="default">
<name>UA Signed Evidence Structure</name> <name>UA-Signed Evidence Structure</name>
<t>The <tt>UA Signed Evidence Structure</tt> (<xref target="drip-data" f <!-- [rfced] Is it correct for "UA-Signed Evidence Structure" to appear in <tt>?
ormat="default"/>) is used by the UA during flight to sign over information elem It seems like it is the name of the set of fields, rather than a field name its
ents using the private key associated with the current UA DET. It is encapsulate elf.
d by the <tt>SAM Authentication Data</tt> field of <xref target="sam-frame" form
at="default"/>.</t> Original:
<t>This structure is used by the DRIP Wrapper (<xref target="drip-wrappe The UA Signed Evidence Structure (Figure 4) is used by the UA during
r" format="default"/>), Manifest <xref target="drip-manifest" format="default"/> flight to sign over information elements using the private key
, and Frame (<xref target="drip-frame" format="default"/>). DRIP Link (<xref tar associated with the current UA DET.
get="drip-link" format="default"/>) MUST NOT use it as it will not fit in the AS -->
TM Authentication Message with its intended content (i.e., a Broadcast Endorseme
nt).</t> <t>The <tt>UA-Signed Evidence Structure</tt> (<xref target="drip-data" f
ormat="default"/>) is used by the UA during flight to sign over information elem
ents using the private key associated with the current UA DET. It is encapsulate
d by the <tt>SAM Authentication Data</tt> field of <xref target="sam-frame" form
at="default"/>.</t>
<t>This structure is used by the DRIP Wrapper (<xref target="drip-wrappe
r" format="default"/>), Manifest <xref target="drip-manifest" format="default"/>
), and Frame (<xref target="drip-frame" format="default"/>). DRIP Link (<xref ta
rget="drip-link" format="default"/>) <bcp14>MUST NOT</bcp14> use it, as it will
not fit in the ASTM Authentication Message with its intended content (i.e., a Br
oadcast Endorsement).</t>
<figure anchor="drip-data"> <figure anchor="drip-data">
<name>Endorsement Structure for UA Signed Evidence</name> <name>Endorsement Structure for UA-Signed Evidence</name>
<artwork align="center" name="" type="" alt=""><![CDATA[ <artwork align="center" name="" type="" alt=""><![CDATA[
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 359 skipping to change at line 455
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
]]></artwork> ]]></artwork>
</figure> </figure>
<t>Valid Not Before (VNB) Timestamp by UA: (4 octets)</t> <dl><dt>Valid Not Before (VNB) Timestamp by UA:</dt><dd><t>(4 octets)</t>
<ul empty="true" spacing="normal"> <t>See <xref target="astm-timestamps" format="default"/>. Set by the UA.
<li>See <xref target="astm-timestamps" format="default"/>. Set by the </t></dd>
UA.</li>
</ul> <dt>Valid Not After (VNA) Timestamp by UA:</dt><dd><t>(4 octets)</t>
<t>Valid Not After (VNA) Timestamp by UA: (4 octets)</t> <t>See <xref target="astm-timestamps" format="default"/>. Set by the UA.<
<ul empty="true" spacing="normal"> /t></dd>
<li>See <xref target="astm-timestamps" format="default"/>. Set by the <dt>Evidence:</dt><dd><t>(0 to 112 octets)</t>
UA.</li> <t>The <tt>Evidence</tt> field <bcp14>MUST</bcp14> be filled in with dat
</ul> a in the form of an opaque object specified in the DRIP Wrapper (<xref target="d
<t>Evidence: (0 to 112 octets)</t> rip-wrapper" format="default"/>), Manifest (<xref target="drip-manifest" format=
<ul empty="true" spacing="normal"> "default"/>), or Frame (<xref target="drip-frame" format="default"/>).</t></dd>
<li>The <tt>evidence</tt> section MUST be filled in with data in the f
orm of an opaque object specified in the DRIP Wrapper (<xref target="drip-wrappe <dt>UA DRIP Entity Tag:</dt><dd><t>(16 octets)</t>
r" format="default"/>), Manifest (<xref target="drip-manifest" format="default"/
>), or Frame (<xref target="drip-frame" format="default"/>).</li> <t>
</ul> This is a DET <xref target="RFC9374" format="default"/> currently being used b
<t>UA DRIP Entity Tag: (16 octets)</t> y the UA for authentication;
<ul empty="true" spacing="normal"> it is assumed to be a Specific Session ID (a type of UAS ID typically also
<li>This is the current DET <xref target="RFC9374" format="default"/> used by the UA in the Basic ID Message).</t></dd>
being used by the UA assumed to be a Specific Session ID (a type of UAS ID).</li
> <dt>UA Signature:</dt><dd><t>(64 octets)</t>
</ul> <t>Signature over the concatenation of preceding fields (<tt>VNB</tt>, <
<t>UA Signature: (64 octets)</t> tt>VNA</tt>, <tt>Evidence</tt>, and <tt>UA DET</tt>) using the keypair of the UA
<ul empty="true" spacing="normal"> DET. The signature algorithm is specified by the Hierarchical Host Identity Tag
<li>Signature over concatenation of preceding fields (<tt>VNB</tt>, <t s (HHIT) Suite ID of the DET.</t></dd></dl>
t>VNA</tt>, <tt>Evidence</tt>, and <tt>UA DET</tt>) using the keypair of the UA
DET. The signature algorithm is specified by the HHIT Suite ID of the DET.</li> <t>When using this structure, the UA is minimally self-endorsing its DET
</ul> . The HI of the UA DET can be looked up by mechanisms described in <xref target=
<t>When using this structure, the UA is minimally self-endorsing its DET "I-D.ietf-drip-registries" format="default"/> or by extracting it from a Broadca
. The HI of the UA DET can be looked up by mechanisms described in <xref target= st Endorsement (see Sections <xref target="drip-link" format="counter"/> and <xr
"drip-registries" format="default"/> or by extracting it from a Broadcast Endors ef target="drip-recommendations" format="counter"/>).</t>
ement (see <xref target="drip-link" format="default"/> and <xref target="drip-re
commendations" format="default"/>).</t>
</section> </section>
<section anchor="drip-link" numbered="true" toc="default"> <section anchor="drip-link" numbered="true" toc="default">
<name>DRIP Link</name> <name>DRIP Link</name>
<t>This SAM Type is used to transmit Broadcast Endorsements. For example , the <tt>BE: HDA, UA</tt> is sent (see <xref target="drip-recommendations" form at="default"/>) as a DRIP Link message.</t> <t>This SAM Type is used to transmit Broadcast Endorsements. For example , the <tt>BE: HDA, UA</tt> is sent (see <xref target="drip-recommendations" for mat="default"/>) as a DRIP Link message.</t>
<t>DRIP Link is important as its contents are used to provide trust in t he DET/HI pair that the UA is currently broadcasting. This message does not requ ire Internet connectivity to perform signature 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 a <tt>BE: HDA, UA</tt>, so that connectivity is not required whe n performing signature verification of other DRIP Authentication Messages.</t> <t>DRIP Link is important as its contents are used to provide trust in t he DET/HI pair that the UA is currently broadcasting. This message does not requ ire Internet connectivity to perform signature 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 a <tt>BE: HDA, UA</tt>, so that connectivity is not required whe n performing signature verification of other DRIP Authentication Messages.</t>
<t>Various Broadcast Endorsements are sent during operation to ensure th <t>
at the full Broadcast Endorsement chain is available offline. See <xref target=" Various Broadcast Endorsements are sent during each UAS flight operation to en
drip-recommendations" format="default"/> for further details.</t> sure
that the full Broadcast Endorsement chain is available offline.
See <xref target="drip-recommendations" format="default"/> for further details.<
/t>
<figure anchor="link-fig"> <figure anchor="link-fig">
<name>Broadcast Endorsement / DRIP Link</name> <name>Broadcast Endorsement / DRIP Link</name>
<artwork align="center" name="" type="" alt=""><![CDATA[ <artwork align="center" name="" type="" alt=""><![CDATA[
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 Parent | | VNB Timestamp by Parent |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| VNA Timestamp by Parent | | VNA Timestamp by Parent |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
skipping to change at line 434 skipping to change at line 531
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
]]></artwork> ]]></artwork>
</figure> </figure>
<t>VNB Timestamp by Parent: (4 octets)</t> <dl><dt>VNB Timestamp by Parent:</dt><dd><t>(4 octets)</t>
<ul empty="true" spacing="normal"> <t>See <xref target="astm-timestamps" format="default"/>. Set by Parent
<li>See <xref target="astm-timestamps" format="default"/>. Set by Pare Entity.</t></dd>
nt Entity.</li> <dt>VNA Timestamp by Parent:</dt><dd><t>(4 octets)</t>
</ul> <t>See <xref target="astm-timestamps" format="default"/>. Set by Parent
<t>VNA Timestamp by Parent: (4 octets)</t> Entity.</t></dd>
<ul empty="true" spacing="normal"> <dt>DET of Child:</dt><dd><t>(16 octets)</t>
<li>See <xref target="astm-timestamps" format="default"/>. Set by Pare <t>DRIP Entity Tag of Child Entity.</t></dd>
nt Entity.</li> <dt>HI of Child:</dt><dd><t>(32 octets)</t>
</ul> <t>Host Identity of Child Entity.</t></dd>
<t>DET of Child: (16 octets)</t> <dt>DET of Parent:</dt><dd><t>(16 octets)</t>
<ul empty="true" spacing="normal"> <t>DRIP Entity Tag of Parent Entity in DIME Hierarchy.</t></dd>
<li>DRIP Entity Tag of Child Entity.</li> <dt>Signature by Parent:</dt><dd><t>(64 octets)</t>
</ul> <t>Signature over concatenation of preceding fields (<tt>VNB</tt>, <tt>V
<t>HI of Child: (32 octets)</t> NA</tt>, <tt>DET of Child</tt>, <tt>HI of Child</tt>, and <tt>DET of Parent</tt>
<ul empty="true" spacing="normal"> ) using the keypair of the Parent DET.</t></dd></dl>
<li>Host Identity of Child Entity.</li>
</ul>
<t>DET of Parent: (16 octets)</t>
<ul empty="true" spacing="normal">
<li>DRIP Entity Tag of Parent Entity in DIME Hierarchy.</li>
</ul>
<t>Signature by Parent: (64 octets)</t>
<ul empty="true" spacing="normal">
<li>Signature over concatenation of preceding fields (<tt>VNB</tt>, <t
t>VNA</tt>, <tt>DET of Child</tt>, <tt>HI of Child</tt>, and <tt>DET of Parent</
tt>) using the keypair of the Parent DET.</li>
</ul>
<t>This DRIP Authentication Message is used in conjunction with other DR IP SAM Types (such as the Manifest or the Wrapper) that contain data (e.g., the ASTM Location/Vector Message, Message Type 0x2) that is guaranteed to be unique, unpredictable, and easily cross-checked by the receiving device.</t> <t>This DRIP Authentication Message is used in conjunction with other DR IP SAM Types (such as the Manifest or the Wrapper) that contain data (e.g., the ASTM Location/Vector Message, Message Type 0x2) that is guaranteed to be unique, unpredictable, and easily cross-checked by the receiving device.</t>
<t>A hash of the final link (<tt>BE: HDA on UA</tt>) in the Broadcast En dorsement chain MUST be included in each DRIP Manifest <xref target="drip-manife st" format="default"/>.</t> <t>A hash of the final link (<tt>BE: HDA on UA</tt>) in the Broadcast En dorsement chain <bcp14>MUST</bcp14> be included in each DRIP Manifest (<xref tar get="drip-manifest" format="default"/>).</t>
</section> </section>
<section anchor="drip-wrapper" numbered="true" toc="default"> <section anchor="drip-wrapper" numbered="true" toc="default">
<name>DRIP Wrapper</name> <name>DRIP Wrapper</name>
<t>This SAM Type is used to wrap and sign over a list of other <xref tar get="F3411" format="default"/> Broadcast RID messages.</t> <t>This SAM Type is used to wrap and sign over a list of other <xref tar get="F3411" format="default"/> Broadcast RID messages.</t>
<t>The <tt>evidence</tt> section of the <tt>UA Signed Evidence Structure </tt> (<xref target="bas" format="default"/>) is populated with up to four ASTM <xref target="F3411" format="default"/> Messages in a contiguous octet sequence. Only ASTM Message Types 0x0, 0x1, 0x3, 0x4, and 0x5 are allowed and must be in Message Type order as defined by <xref target="F3411" format="default"/>. These messages MUST include the Message Type and Protocol Version octet and MUST NOT i nclude the Message Counter octet (thus are fixed at 25 octets in length).</t> <t>The <tt>Evidence</tt> field of the <tt>UA-Signed Evidence Structure</ tt> (<xref target="bas" format="default"/>) is populated with up to four ASTM Me ssages <xref target="F3411" format="default"/> in a contiguous octet sequence. O nly ASTM Message Types 0x0, 0x1, 0x3, 0x4, and 0x5 are allowed and must be in Me ssage Type order as defined by <xref target="F3411" format="default"/>. These me ssages <bcp14>MUST</bcp14> include the Message Type and Protocol Version octet a nd <bcp14>MUST NOT</bcp14> include the Message Counter octet (thus are fixed at 25 octets in length).</t>
<section anchor="wrapped-count-format-validation" numbered="true" toc="d efault"> <section anchor="wrapped-count-format-validation" numbered="true" toc="d efault">
<name>Wrapped Count &amp; Format Validation</name> <name>Wrapped Count and Format Validation</name>
<t>When decoding a DRIP Wrapper on a receiver, a calculation of the nu <t>When decoding a DRIP Wrapper on a receiver, a calculation of the nu
mber of messages wrapped and a validation MUST be performed by using the number mber of messages wrapped and a validation <bcp14>MUST</bcp14> be performed by us
of octets (defined as <tt>wrapperLength</tt>) between the <tt>VNA Timestamp by U ing the number of octets (defined as <tt>wrapperLength</tt>) between the <tt>VNA
A</tt> and the <tt>UA DET</tt> as shown in <xref target="wrapper-check" format=" Timestamp by UA</tt> and the <tt>UA DET</tt> as shown in <xref target="wrapper-
default"/>.</t> check" format="default"/>.</t>
<figure anchor="wrapper-check"> <figure anchor="wrapper-check">
<name>Pseudo-code for Wrapper validation and number of messages calc <name>Pseudocode for Wrapper Validation and Number of Messages calcu
ulation</name> lation</name>
<sourcecode name="" type="" markers="true"><![CDATA[
<sourcecode name="" type="pseudocode" markers="true"><![CDATA[
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 {
skipping to change at line 484 skipping to change at line 569
} }
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
} }
]]></sourcecode> ]]></sourcecode>
</figure> </figure>
</section> </section>
<section anchor="extended-wrapper" numbered="true" toc="default"> <section anchor="extended-wrapper" numbered="true" toc="default">
<name>Wrapper over Extended Transports</name> <name>Wrapper over Extended Transports</name>
<t>When using Extended Transports an optimization can be made to DRIP <t>When using Extended Transports, an optimization to DRIP Wrapper can
Wrapper to sign over co-located data in an ASTM Message Pack (Message Type 0xF). be made to sign over co-located data in an ASTM Message Pack (Message Type 0xF)
</t> .</t>
<t>To perform this optimization the <tt>UA Signed Evidence Structure</ <t>To perform this optimization, the <tt>UA-Signed Evidence Structure<
tt> is filled with the ASTM Messages to be in the ASTM Message Pack, the signatu /tt> is filled with the ASTM Messages to be in the ASTM Message Pack, the signat
re is generated, then the <tt>evidence</tt> field is cleared leaving the encoded ure is generated, and then the <tt>Evidence</tt> field is cleared, leaving the e
form shown in <xref target="set-sig" format="default"/>.</t> ncoded form shown in <xref target="set-sig" format="default"/>.</t>
<figure anchor="set-sig"> <figure anchor="set-sig">
<name>DRIP Wrapper over Extended Transports</name> <name>DRIP Wrapper over Extended Transports</name>
<artwork align="center" name="" type="" alt=""><![CDATA[ <artwork align="center" name="" type="" alt=""><![CDATA[
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 526 skipping to change at line 610
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
]]></artwork> ]]></artwork>
</figure> </figure>
<t>To verify the signature, the receiver MUST concatenate all the mess <t>To verify the signature, the receiver <bcp14>MUST</bcp14> concatena
ages in the Message Pack (excluding Authentication Message found in the same Mes te all the messages in the Message Pack (excluding the Authentication Message fo
sage Pack) in ASTM Message Type order and set the <tt>evidence</tt> section of t und in the same Message Pack) in ASTM Message Type order and set the <tt>Evidenc
he <tt>UA Signed Evidence Structure</tt> before performing signature verificatio e</tt> field of the <tt>UA-Signed Evidence Structure</tt> before performing sign
n.</t> ature verification.</t>
<t>The functionality of a Wrapper in this form is equivalent to Messag <t>The functionality of a Wrapper in this form is equivalent to Messag
e Set Signature (Authentication Type 0x3) when running over Extended Transports. e Set Signature (Authentication Type 0x3) when running over Extended Transports.
What the Wrapper provides is the same format but over both Extended and Legacy The Wrapper provides the same format but over both Extended and Legacy Transpor
Transports allowing the transports to be similar. Message Set Signature also imp ts, which allows the transports to be similar. Message Set Signature also implie
lies using the ASTM validator system architecture which depends on Internet conn s using the ASTM validator system architecture, which depends on Internet connec
ectivity for verification which the receiver may not have at the time of receipt tivity for verification that the receiver may not have at the time an Authentica
of an Authentication Message. This is something the Wrapper, and all DRIP Authe tion Message is received. This is something the Wrapper, and all DRIP Authentica
ntication Formats, avoid when the UA key is obtained via a DRIP Link Authenticat tion Formats, avoid when the UA key is obtained via a DRIP Link Authentication M
ion Message.</t> essage.</t>
</section> </section>
<section anchor="wrapper-limitations" numbered="true" toc="default"> <section anchor="wrapper-limitations" numbered="true" toc="default">
<name>Wrapper Limitations</name> <name>Wrapper Limitations</name>
<t>The primary limitation of the Wrapper is the bounding of up to 4 AS TM Messages that can be sent within it. Another limitation is that the format ca nnot be used as a surrogate for messages it is wrapping due to the potential tha t an Observer on the ground does not support DRIP. Thus, when a Wrapper is being used, the wrapped data must effectively be sent twice, once as a single framed message (as specified in <xref target="F3411" format="default"/>) and then again within the Wrapper.</t> <t>The primary limitation of the Wrapper is the bounding of up to four ASTM Messages that can be sent within it. Another limitation is that the format cannot be used as a surrogate for messages it is wrapping due to the potential that an Observer on the ground does not support DRIP. Thus, when a Wrapper is be ing used, the wrapped data must effectively be sent twice, once as a single-fram ed message (as specified in <xref target="F3411" format="default"/>) and again w ithin the Wrapper.</t>
</section> </section>
</section> </section>
<section anchor="drip-manifest" numbered="true" toc="default"> <section anchor="drip-manifest" numbered="true" toc="default">
<name>DRIP Manifest</name> <name>DRIP Manifest</name>
<t>This SAM Type is used to create message manifests that contain hashes of previously sent ASTM Messages.</t> <t>This SAM Type is used to create message manifests that contain hashes of previously sent ASTM Messages.</t>
<t>By hashing previously sent messages and signing them, we gain trust i <t>By hashing previously sent messages and signing them, we gain trust i
n a UA's previous reports without re-transmitting them. This is a way to evade t n a UA's previous reports without retransmitting them. This is a way to evade th
he limitation of a maximum of 4 messages in the Wrapper (<xref target="wrapper-l e limitation of a maximum of four messages in the Wrapper (<xref target="wrapper
imitations" format="default"/>) and greatly reduce overhead.</t> -limitations" format="default"/>) and greatly reduce overhead.</t>
<t>Observers MUST hash all received ASTM Messages and cross-check them a <t>Observers <bcp14>MUST</bcp14> hash all received ASTM Messages and cro
gainst hashes in received Manifests.</t> ss-check them against hashes in received Manifests.</t>
<t>Judicious use of a Manifest enables an entire Broadcast RID message s tream to be strongly authenticated with less than 100% overhead relative to a co mpletely unauthenticated message stream (see <xref target="drip-recommendations" format="default"/> and <xref target="operational-proof" format="default"/>).</t > <t>Judicious use of a Manifest enables an entire Broadcast RID message s tream to be strongly authenticated with less than 100% overhead relative to a co mpletely unauthenticated message stream (see <xref target="drip-recommendations" format="default"/> and <xref target="operational-proof" format="default"/>).</t >
<t>The <tt>evidence</tt> section of the <tt>UA Signed Evidence Structure <t>The <tt>Evidence</tt> field of the <tt>UA-Signed Evidence Structure</
</tt> (<xref target="bas" format="default"/>) is populated with 8-octet hashes o tt> (<xref target="bas" format="default"/>) is populated with 8-octet hashes of
f <xref target="F3411" format="default"/> Broadcast RID messages (up to 11) and <xref target="F3411" format="default"/> Broadcast RID messages (up to 11) and th
three special hashes (<xref target="block-hashes" format="default"/>). All these ree special hashes (<xref target="block-hashes" format="default"/>). All of thes
hashes MUST be concatenated to form a contiguous octet sequence in the <tt>evid e hashes <bcp14>MUST</bcp14> be concatenated to form a contiguous octet sequence
ence</tt> section. It is RECOMMENDED the max number of ASTM Message Hashes be us in the <tt>Evidence</tt> field. It is <bcp14>RECOMMENDED</bcp14> that the maxim
ed is 10 (see <xref target="eleven-astm-messages" format="default"/>).</t> um number of ASTM Message Hashes used be 10 (see <xref target="eleven-astm-messa
<t>The <tt>Previous Manifest Hash</tt>, <tt>Current Manifest Hash</tt>, ges" format="default"/>).</t>
and <tt>DRIP Link (BE: HDA, UA) Hash</tt> MUST always come before the <tt>ASTM M <t>The <tt>Previous Manifest Hash</tt>, <tt>Current Manifest Hash</tt>,
essage Hashes</tt> as seen in <xref target="manifest-fig" format="default"/>.</t and <tt>DRIP Link (BE: HDA, UA) Hash</tt> <bcp14>MUST</bcp14> always come before
> the <tt>ASTM Message Hashes</tt> as seen in <xref target="manifest-fig" format=
<t>An Observer MUST use the Manifest to verify each ASTM Message hashed "default"/>.</t>
therein that it has previously received. It can do this without having received <t>An Observer <bcp14>MUST</bcp14> use the Manifest to verify each ASTM
them all. A Manifest SHOULD typically encompass a single transmission cycle of m Message hashed therein that it has previously received. It can do this without h
essages being sent, see <xref target="operational-recommendations" format="defau aving received them all. A Manifest <bcp14>SHOULD</bcp14> typically encompass a
lt"/> and <xref target="operational-proof" format="default"/>.</t> single transmission cycle of messages being sent; see <xref target="operational-
recommendations" format="default"/> and <xref target="operational-proof" format=
"default"/>.</t>
<figure anchor="manifest-fig"> <figure anchor="manifest-fig">
<name>DRIP Manifest Evidence Structure</name> <name>DRIP Manifest Evidence Structure</name>
<artwork align="center" name="" type="" alt=""><![CDATA[ <artwork align="center" name="" type="" alt=""><![CDATA[
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
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| Previous Manifest | | Previous Manifest |
| Hash | | Hash |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| Current Manifest | | Current Manifest |
skipping to change at line 566 skipping to change at line 650
| Hash | | Hash |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| | | |
. . . .
. ASTM Message Hashes . . ASTM Message Hashes .
. . . .
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
]]></artwork> ]]></artwork>
</figure> </figure>
<t>Previous Manifest Hash: (8 octets)</t> <dl>
<ul empty="true" spacing="normal"> <dt>Previous Manifest Hash:</dt><dd><t>(8 octets)</t>
<li>Hash of the previously sent Manifest Message.</li> <t>Hash of the previously sent Manifest Message.</t></dd>
</ul> <dt>Current Manifest Hash:</dt><dd><t>(8 octets)</t>
<t>Current Manifest Hash: (8 octets)</t> <t>Hash of the current Manifest Message.</t></dd>
<ul empty="true" spacing="normal"> <dt>DRIP Link (BE: HDA, UA):</dt><dd><t>(8 octets)</t>
<li>Hash of the current Manifest Message.</li> <t>Hash of the DRIP Link Authentication Message carrying <tt>BE: HDA,
</ul> UA</tt> (see <xref target="drip-link" format="default"/>).</t></dd>
<t>DRIP Link (BE: HDA, UA): (8 octets)</t> <dt>ASTM Message Hash:</dt><dd><t>(8 octets)</t>
<ul empty="true" spacing="normal"> <t>Hash of a single full ASTM Message using hash operations described
<li>Hash of the DRIP Link Authentication Message carrying <tt>BE: HDA, in <xref target="hash-op" format="default"/>.</t></dd></dl>
UA</tt> (see <xref target="drip-link" format="default"/>).</li>
</ul>
<t>ASTM Message Hash: (8 octets)</t>
<ul empty="true" spacing="normal">
<li>Hash of a single full ASTM Message using hash operations described
in <xref target="hash-op" format="default"/>.</li>
</ul>
<section anchor="hash-count-format-validation" numbered="true" toc="defa ult"> <section anchor="hash-count-format-validation" numbered="true" toc="defa ult">
<name>Hash Count &amp; Format Validation</name> <name>Hash Count and Format Validation</name>
<t>When decoding a DRIP Manifest on a receiver, a calculation of the n <t>When decoding a DRIP Manifest on a receiver, a calculation of the n
umber of hashes and a validation can be performed by using the number of octets umber of hashes and a validation can be performed by using the number of octets
(defined as <tt>manifestLength</tt>) between the <tt>UA DET</tt> and the <tt>VNB between the <tt>UA DET</tt> and the <tt>VNB Timestamp by UA</tt> (defined as
Timestamp by UA</tt> such as shown in <xref target="manifest-check" format="def <tt>manifestLength</tt>) such as shown in <xref target="manifest-check" format="
ault"/>.</t> default"/>.</t>
<figure anchor="manifest-check"> <figure anchor="manifest-check">
<name>Pseudo-code for Manifest Sanity Check and Number of Hashes Cal <name>Pseudocode for Manifest Sanity Check and Number of Hashes Calc
culation</name> ulation</name>
<sourcecode name="" type="" markers="true"><![CDATA[
<sourcecode name="" type="pseudocode" markers="true"><![CDATA[
if (manifestLength MOD 8) != 0 { if (manifestLength MOD 8) != 0 {
return DECODE_FAILURE return DECODE_FAILURE
} }
hashCount = (manifestLength / 8) - 3; hashCount = (manifestLength / 8) - 3;
]]></sourcecode> ]]></sourcecode>
</figure> </figure>
</section> </section>
<section anchor="block-hashes" numbered="true" toc="default"> <section anchor="block-hashes" numbered="true" toc="default">
<name>Manifest Ledger Hashes</name> <name>Manifest Ledger Hashes</name>
<t>Three special hashes are included in all Manifests. The <tt>Previou <t>
s Manifest Hash</tt>, links to the previous Manifest, and the <tt>Current Manife The following three special hashes are included in all Manifests:</t>
st Hash</tt> is of the Manifest in which it appears. These two hashes act as a l <ul>
edger of provenance to the Manifest that could be traced back if the Observer wa <li>the <tt>Previous Manifest Hash</tt> links to the previous Manifest.</li>
s present for extended periods of time.</t> <li>the <tt>Current Manifest Hash</tt> is of the Manifest in which it appears.
<t>The <tt>DRIP Link (BE: HDA, UA)</tt> is included so there is a dire </li>
ct signature by the UA over the Broadcast Endorsement (see <xref target="drip-li <li>the <tt>DRIP Link (BE: HDA, UA) Hash</tt> ties the endorsed UA key to the
nk" format="default"/>). Typical operation would expect that the list of <tt>AST Manifest chain.</li></ul>
M Message Hash</tt>'s contain nonce-link data. To enforce a binding between the <t>
<tt>BE: HDA, UA</tt> and avoid trivial replay attack vectors (see <xref target=" The Previous and Current hashes act as a ledger of provenance for the Manifest
replay-attacks" format="default"/>) at least 1 <tt>ASTM Message Hash</tt> MUST b chain,
e from an <xref target="F3411" format="default"/> message that satisfies the 4th which should be traced back if the Observer and UA were within Broadcast RID w
requirement in <xref target="drip-recommendations" format="default"/>.</t> ireless range
of each other for an extended period of time.</t>
<t>The <tt>DRIP Link (BE: HDA, UA)</tt> is included so there is a dire
ct signature by the UA over the Broadcast Endorsement (see <xref target="drip-li
nk" format="default"/>). Typical operation would expect that the list of <tt>AST
M Message Hashes</tt> contain nonce-like data. To enforce a binding between the
<tt>BE: HDA, UA</tt> and avoid trivial replay attack vectors (see <xref target="
replay-attacks" format="default"/>), at least one <tt>ASTM Message Hash</tt> <bc
p14>MUST</bcp14> be from an <xref target="F3411" format="default"/> message that
satisfies the fourth requirement in <xref target="drip-recommendations" format=
"default"/>.</t>
</section> </section>
<section anchor="hash-op" numbered="true" toc="default"> <section anchor="hash-op" numbered="true" toc="default">
<name>Hash Algorithms and Operation</name> <name>Hash Algorithms and Operation</name>
<t>The hash algorithm used for the Manifest is the same hash algorithm used in creation of the DET <xref target="RFC9374" format="default"/> that is s igning the Manifest. This is encoded as part of the DET using the HHIT Suite ID. </t> <t>The hash algorithm used for the Manifest is the same hash algorithm used in creation of the DET <xref target="RFC9374" format="default"/> that is s igning the Manifest. This is encoded as part of the DET using the HHIT Suite ID. </t>
<t>DET's using cSHAKE128 <xref target="NIST.SP.800-185" format="defaul <t>DETs that use cSHAKE128 <xref target="NIST.SP.800-185" format="defa
t"/> compute the hash as follows:</t> ult"/> compute the hash as follows:</t>
<artwork name="" type="" align="left" alt=""><![CDATA[ <artwork name="" type="" align="left" alt=""><![CDATA[
cSHAKE128(ASTM Message, 64, "", "Remote ID Auth Hash") cSHAKE128(ASTM Message, 64, "", "Remote ID Auth Hash")
]]></artwork> ]]></artwork>
<t>For OGAs other than "5" <xref target="RFC9374" format="default"/>, <t>For ORCHID Generation Algorithms (OGAs) other than "5" (EdDSA/cSHAK
use the construct appropriate for the associated hash. For example, for "2" whic E128) <xref target="RFC9374" format="default"/>, use the construct appropriate f
h is ECDSA/SHA-384:</t> or the associated hash. For example, the hash for "2" (ECDSA/SHA-384) is compute
<artwork name="" type="" align="left" alt=""><![CDATA[ d as follows:</t>
Ltrunc( SHA-384( ASTM Message | "Remote ID Auth Hash" ), 8 ) <artwork name="" type="" align="left" alt=""><![CDATA[
Ltrunc( SHA-384( ASTM Message | "Remote ID Auth Hash" ), 8 )
]]></artwork> ]]></artwork>
<t>When building the list of hashes, the <tt>Previous Manifest Hash</t t> is known from the previous Manifest. For the first built Manifest this value is filled with a random nonce. The <tt>Current Manifest Hash</tt> is null filled while ASTM Messages are hashed and fill the <tt>ASTM Messages Hashes</tt> secti on. When all messages are hashed, the <tt>Current Manifest Hash</tt> is computed over the <tt>Previous Manifest Hash</tt>, <tt>Current Manifest Hash</tt> (null filled) and <tt>ASTM Messages Hashes</tt>. This hash value replaces the null fil led <tt>Current Manifest Hash</tt> and becomes the <tt>Previous Manifest Hash</t t> for the next Manifest.</t> <t>When building the list of hashes, the <tt>Previous Manifest Hash</t t> is known from the previous Manifest. For the first built Manifest, this value is filled with a random nonce. The <tt>Current Manifest Hash</tt> is null fille d while ASTM Messages are hashed and fill the <tt>ASTM Message Hashes</tt> field . When all messages are hashed, the <tt>Current Manifest Hash</tt> is computed o ver the <tt>Previous Manifest Hash</tt>, <tt>Current Manifest Hash</tt> (null fi lled), and <tt>ASTM Message Hashes</tt>. This hash value replaces the null-fille d <tt>Current Manifest Hash</tt> and becomes the <tt>Previous Manifest Hash</tt> for the next Manifest.</t>
<section anchor="legacy-transport-hashing" numbered="true" toc="defaul t"> <section anchor="legacy-transport-hashing" numbered="true" toc="defaul t">
<name>Legacy Transport Hashing</name> <name>Legacy Transport Hashing</name>
<t>Under this transport DRIP hashes the full ASTM Message being sent <t>Under this transport, DRIP hashes the full ASTM Message being sen
over the Bluetooth Advertising frame. This is the 25-octet object start with th t over the Bluetooth Advertising frame. This is the 25-octet object that starts
e Message Type and Protocol Version octet along with the 24 octets of message da with the Message Type and Protocol Version octet along with the 24 octets of mes
ta. The hash MUST NOT included the Message Counter octet.</t> sage data. The hash <bcp14>MUST NOT</bcp14> include the Message Counter octet.</
<t>For paged ASTM Messages (currently only Authentication Messages) t>
all the pages are concatenated together in Page Number order and hashed as one o <t>For paged ASTM Messages (currently only Authentication Messages),
bject.</t> all of the pages are concatenated together in Page Number order and hashed as o
ne object.</t>
</section> </section>
<section anchor="extended-transport-hashing" numbered="true" toc="defa ult"> <section anchor="extended-transport-hashing" numbered="true" toc="defa ult">
<name>Extended Transport Hashing</name> <name>Extended Transport Hashing</name>
<t>Under this transport DRIP hashes the full ASTM Message Pack (Mess age Type 0xF) regardless of its content. The hash MUST NOT included the Message Counter octet.</t> <t>Under this transport, DRIP hashes the full ASTM Message Pack (Mes sage Type 0xF) regardless of its content. The hash <bcp14>MUST NOT</bcp14> inclu de the Message Counter octet.</t>
</section> </section>
</section> </section>
</section> </section>
<section anchor="drip-frame" numbered="true" toc="default"> <section anchor="drip-frame" numbered="true" toc="default">
<name>DRIP Frame</name> <name>DRIP Frame</name>
<t>This SAM Type is defined to enable the use of <xref target="bas" form <t>
at="default"/> in the future beyond the previously defined formats (Wrapper and This SAM Type is defined to enable use of the <tt>UA-Signed Evidence Structure
Manifest) by the inclusion of a single octet to signal the format of <tt>evidenc </tt>
e</tt> data (up to 111 octets).</t> (<xref target="bas" format="default"/>) in the future beyond the previously de
<t>The content format of <tt>Frame Evidence Data</tt> is not defined in fined formats (Wrapper and
this document. Other specifications MUST define the contents and register for a Manifest) by the inclusion of a single octet to signal the format of <tt>Evide
<tt>Frame Type</tt>. At the time of publication there are no defined Frame Types nce</tt>
other than an Experimental range.</t> data (up to 111 octets).</t>
<t>Observers MUST check the signature of the structure (<xref target="ba
s" format="default"/>) per <xref target="ua-attestation" format="default"/> and <t>The content format of <tt>Frame Evidence Data</tt> is not defined in
MAY, if the specification of <tt>Frame Type</tt> is known, parse the content in this document. Other specifications <bcp14>MUST</bcp14> define the contents and
<tt>Frame Evidence Data</tt>.</t> register for a <tt>Frame Type</tt>. At the time of publication (2024), there are
no defined Frame Types; only an Experimental range has been defined.</t>
<t>Observers <bcp14>MUST</bcp14> check the signature of the structure (<
xref target="bas" format="default"/>) per <xref target="ua-attestation" format="
default"/> and <bcp14>MAY</bcp14>, if the specification of <tt>Frame Type</tt> i
s known, parse the content in <tt>Frame Evidence Data</tt>.</t>
<figure anchor="frame-fig"> <figure anchor="frame-fig">
<name>DRIP Frame</name> <name>DRIP Frame</name>
<artwork align="center" name="" type="" alt=""><![CDATA[ <artwork align="center" name="" type="" alt=""><![CDATA[
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 .
. . . .
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
]]></artwork> ]]></artwork>
</figure> </figure>
<t>Frame Type: (1 octet)</t> <dl>
<ul empty="true" spacing="normal"> <dt>Frame Type:</dt><dd><t>(1 octet)</t>
<li>Byte to sub-type for future different DRIP Frame formats. It takes <t>
the first octet in <xref target="frame-fig" format="default"/>, leaving 111 oct As shown in <xref target="frame-fig" format="default"/>, the <tt>Frame Typ
ets available for <tt>Frame Evidence Data</tt>. See <xref target="iana-drip-regi e</tt> takes the first octet, which
stry" format="default"/> for Frame Type allocations.</li> leaves 111 octets available for <tt>Frame Evidence Data</tt>. See <xref t
</ul> arget="iana-drip-registry" format="default"/> for Frame Type allocations.</t></d
d></dl>
</section> </section>
</section> </section>
<section anchor="fec-details" numbered="true" toc="default"> <section anchor="fec-details" numbered="true" toc="default">
<name>Forward Error Correction</name> <name>Forward Error Correction</name>
<t>For Broadcast RID, FEC is provided by the lower layers in Extended Tran sports. The Bluetooth 4.x Legacy Transport does not have supporting FEC, so with DRIP Authentication the following application level scheme is used to add some FEC. When sending data over a medium that does not have underlying FEC, for exam ple Bluetooth 4.x, then this section MUST be used.</t> <t>For Broadcast RID, FEC is provided by the lower layers in Extended Tran sports. The Bluetooth 4.x Legacy Transport does not support FEC, so the followin g application-level scheme is used with DRIP Authentication to add some FEC. Whe n sending data over a medium that does not have underlying FEC, for example Blue tooth 4.x, this section <bcp14>MUST</bcp14> be used.</t>
<t>The Bluetooth 4.x lower layers have error detection but not correction. Any frame in which Bluetooth detects an error is dropped and not delivered to h igher layers (in our case, DRIP). Thus it can be treated as an erasure.</t> <t>The Bluetooth 4.x lower layers have error detection but not correction. Any frame in which Bluetooth detects an error is dropped and not delivered to h igher layers (in our case, DRIP). Thus it can be treated as an erasure.</t>
<t>DRIP standardizes a single page FEC scheme using XOR parity across all <t>DRIP standardizes a single page FEC scheme using XOR parity across all
page data of an Authentication Message. This allows the correction of single era page data of an Authentication Message. This allows the correction of a single e
sed page in an Authentication Message. If more than a single page is missing the rased page in an Authentication Message. If more than a single page is missing,
n handling of an incomplete Authentication Message is determined by higher layer then handling of an incomplete Authentication Message is determined by higher la
s.</t> yers.</t>
<t>Other FEC schemes, to protect more than a single page of an Authenticat <t>Other FEC schemes, to protect more than a single page of an Authenticat
ion Message or multiple <xref target="F3411" format="default"/> Messages, is lef ion Message or multiple <xref target="F3411" format="default"/> Messages, are le
t for future standardization if operational experience proves it necessary and/o ft for future standardization if operational experience proves it necessary and/
r practical.</t> or practical.</t>
<t>The data added during FEC is not included in the <tt>Authentication Dat <t>The data added during FEC is not included in the <tt>Authentication Dat
a / Signature</tt>, but instead in the <tt>Additional Data</tt> field of <xref t a / Signature</tt>, but instead in the <tt>Additional Data</tt> field of <xref t
arget="astm-auth" format="default"/>. This may cause the Authentication Message arget="astm-auth" format="default"/>. This may cause the Authentication Message
to exceed 9-pages, up to a maximum of 16-pages.</t> to exceed 9 pages, up to a maximum of 16 pages.</t>
<section anchor="enc-single-page" numbered="true" toc="default"> <section anchor="enc-single-page" numbered="true" toc="default">
<name>Encoding</name> <name>Encoding</name>
<t>When encoding two things are REQUIRED:</t> <t>When encoding, two things are <bcp14>REQUIRED</bcp14>:</t>
<ol spacing="normal" type="1"><li>The FEC data MUST start on a new Authe <ol spacing="normal" type="1">
ntication Page. To do this, the results of parity encoding MUST be placed in the <li>The FEC data <bcp14>MUST</bcp14> start on a new Authentication
<tt>Additional Data</tt> field of <xref target="astm-auth" format="default"/> w Page. To do this, the results of parity encoding <bcp14>MUST</bcp14>
ith null padding before it to line up with the next page. The <tt>Additional Dat be placed in the <tt>Additional Data</tt> field of <xref
a Length</tt> field MUST be set to <tt>number of padding octets + number of pari target="astm-auth" format="default"/> with null padding before it to
ty octets</tt>.</li> line up with the next page. The <tt>Additional Data Length</tt>
<li>The <tt>Last Page Index</tt> field (in Page 0) MUST be incremented field <bcp14>MUST</bcp14> be set to <tt>number of padding octets +
from what it would have been without FEC by the number of pages required for th number of parity octets</tt>.</li>
e <tt>Additional Data Length</tt> field, null padding and FEC.</li> <li>The <tt>Last Page Index</tt> field (in Page 0)
<bcp14>MUST</bcp14> be incremented from what it would have been
without FEC by the number of pages required for the <tt>Additional
Data Length</tt> field, null padding, and FEC.</li>
</ol> </ol>
<t>To generate the parity, a simple XOR operation using the previous par ity page and current page is used. Only the 23-octet <tt>Authentication Payload< /tt> field of <xref target="astm-auth-page" format="default"/> is used in the XO R operations. For Page 0, a 23-octet null pad is used for the previous parity pa ge.</t> <t>To generate the parity, a simple XOR operation using the previous par ity page and current page is used. Only the 23-octet <tt>Authentication Payload< /tt> field of <xref target="astm-auth-page" format="default"/> is used in the XO R operations. For Page 0, a 23-octet null pad is used for the previous parity pa ge.</t>
<t><xref target="fig-single-fec" format="default"/> shows an example of the last two pages (out of N) of an Authentication Message using DRIP Single Pag e FEC. The <tt>Additional Data Length</tt> is set to 33 as there are always 23 o ctets of FEC data and in this example 10 octets of padding to line it up into Pa ge N.</t> <t><xref target="fig-single-fec" format="default"/> shows an example of the last two pages (out of N) of an Authentication Message using DRIP Single Pag e FEC. The <tt>Additional Data Length</tt> 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 Page N.</t>
<figure anchor="fig-single-fec"> <figure anchor="fig-single-fec">
<name>Example Single Page FEC Encoding</name> <name>Example Single Page FEC Encoding</name>
<artwork align="center" name="" type="" alt=""><![CDATA[ <artwork align="center" name="" type="" alt=""><![CDATA[
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 700 skipping to change at line 803
| Forward Error Correction | | Forward Error Correction |
| | | |
| | | |
| | | |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
]]></artwork> ]]></artwork>
</figure> </figure>
</section> </section>
<section anchor="dec-single-page" numbered="true" toc="default"> <section anchor="dec-single-page" numbered="true" toc="default">
<name>Decoding</name> <name>Decoding</name>
<t>Frame decoding is independent of the transmit media. However the deco <t>Frame decoding is independent of the transmit media. However, the dec
ding process can determine from the first Authentication page that there may be oding process can determine from the first Authentication page that there may be
a Bluetooth 4.x FEC page at the end. The decoding process MUST test for the pres a Bluetooth 4.x FEC page at the end. The decoding process <bcp14>MUST</bcp14> t
ence of FEC and apply it as follows.</t> est for the presence of FEC and apply it as follows.</t>
<t>To determine if FEC has been used, a check of the <tt>Last Page Index <t>To determine if FEC has been used, a check of the <tt>Last Page Index
</tt> is performed. In general if the <tt>Last Page Index</tt> field is one grea </tt> is performed. In general, if the <tt>Last Page Index</tt> field is one gre
ter than that necessary to hold <tt>Length</tt> octets of Authentication Data th ater than that necessary to hold <tt>Length</tt> octets of Authentication Data,
en FEC has been used. Note that if <tt>Length</tt> octets are exhausted exactly then FEC has been used. Note that if <tt>Length</tt> octets are exhausted exactl
at the end of an Authentication Page, the <tt>Additional Data Length</tt> field y at the end of an Authentication Page, the <tt>Additional Data Length</tt> fiel
will occupy the first octet of the following page. The remainder of this page wi d will occupy the first octet of the following page. The remainder of this page
ll be null padded under DRIP to align the FEC to its own page. In this case the will be null padded under DRIP to align the FEC to its own page. In this case, t
<tt>Last Page Index</tt> will have been incremented once for initializing the <t he <tt>Last Page Index</tt> will have been incremented once for initializing the
t>Additional Data Length</tt> field and once for FEC page, for a total of two ad <tt>Additional Data Length</tt> field and once for the FEC page, for a total of
ditional pages, as in the last row of <xref target="tbl-page-counts" format="def two additional pages, as in the last row of <xref target="tbl-page-counts" form
ault"/>.</t> at="default"/>.</t>
<t>To decode FEC in DRIP, a rolling XOR is used on each <tt>Authenticati <t>To decode FEC in DRIP, a rolling XOR is used on each <tt>Authenticati
on Page</tt> received in the current <tt>Authentication Message</tt>. A Message on Page</tt> received in the current <tt>Authentication Message</tt>. A Message
Counter, outside of the ASTM Message but specified in <xref target="F3411" forma Counter, outside of the ASTM Message but specified in <xref target="F3411" forma
t="default"/>, is used to signal a different <tt>Authentication Message</tt> and t="default"/>, is used to signal a different <tt>Authentication Message</tt> and
to correlate pages to messages. This Message Counter is only single octet in le to correlate pages to messages. This Message Counter is only a single octet in
ngth, so it will roll over (to 0x00) after reaching its maximum value (0xFF). If length, so it will roll over (to 0x00) after reaching its maximum value (0xFF).
only a single page is missing in the <tt>Authentication Message</tt> the result If only a single page is missing in the <tt>Authentication Message</tt> the resu
ing parity octets should be the data of the erased page.</t> lting parity octets should be the data of the erased page.</t>
<t>Authentication Page 0 contains various important fields, only located <t>Authentication Page 0 contains various important fields, only located
on that page, that help decode the full ASTM Authentication Message. If Page 0 on that page, that help decode the full ASTM Authentication Message. If Page 0
has been reconstructed, the <tt>Last Page Index</tt> and <tt>Length</tt> fields has been reconstructed, the <tt>Last Page Index</tt> and <tt>Length</tt> fields
MUST be validated by DRIP. The pseudo-code in <xref target="decode-pseudo" forma <bcp14>MUST</bcp14> be validated by DRIP. The pseudocode in <xref target="decode
t="default"/> can be used for both checks.</t> -pseudo" format="default"/> can be used for both checks.</t>
<figure anchor="decode-pseudo"> <figure anchor="decode-pseudo">
<name>Pseudo-code for Decode Checks</name> <name>Pseudocode for Decode Checks</name>
<sourcecode name="" type="" markers="true"><![CDATA[
<sourcecode name="" type="pseudocode" markers="true"><![CDATA[
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
} }
// check that decoded length does not exceed DRIP maximum value // check that decoded length does not exceed DRIP maximum value
if (decoded_length > 201) { if (decoded_length > 201) {
return DECODE_FAILURE return DECODE_FAILURE
} }
skipping to change at line 736 skipping to change at line 839
return DECODE_FAILURE return DECODE_FAILURE
} }
// 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 LPI // use the presumed ADL to calculate a presumed
//Last Page Index (LPI, a field defined in <xref target="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
} }
]]></sourcecode> ]]></sourcecode>
</figure> </figure>
</section> </section>
<section anchor="fec-limitations" numbered="true" toc="default"> <section anchor="fec-limitations" numbered="true" toc="default">
<name>FEC Limitations</name> <name>FEC Limitations</name>
<t>The worst-case scenario is when the <tt>Authentication Data / Signatu re</tt> ends perfectly on a page boundary (Page N-1). This means the <tt>Additio nal Data Length</tt> would start the next page (Page N) and have 22 octets worth of null padding to align the FEC to begin at the start of the next page (Page N +1). In this scenario, an entire page (Page N) is being wasted just to carry the <tt>Additional Data Length</tt>.</t> <t>The worst-case scenario is when the <tt>Authentication Data / Signatu re</tt> ends perfectly on a page boundary (Page N-1). This means the <tt>Additio nal Data Length</tt> would start the next page (Page N) and have 22 octets worth of null padding to align the FEC to begin at the start of the next page (Page N +1). In this scenario, an entire page (Page N) is being wasted just to carry the <tt>Additional Data Length</tt>.</t>
</section> </section>
</section> </section>
<section anchor="reqs" numbered="true" toc="default"> <section anchor="reqs" numbered="true" toc="default">
<name>Requirements &amp; Recommendations</name> <name>Requirements and Recommendations</name>
<section anchor="legacy-transports" numbered="true" toc="default"> <section anchor="legacy-transports" numbered="true" toc="default">
<name>Legacy Transports</name> <name>Legacy Transports</name>
<t>Under DRIP, the goal is to attempt to bring reliable receipt of the p <t>Under DRIP, the goal is to bring reliable receipt of the paged Authen
aged Authentication Message using Legacy Transports. FEC (<xref target="fec-deta tication Message using Legacy Transports. FEC (<xref target="fec-details" format
ils" format="default"/>) MUST be used, per mandated RID rules (for example the U ="default"/>) <bcp14>MUST</bcp14> be used, per mandated RID rules (for example,
S FAA RID Rule <xref target="FAA-14CFR" format="default"/>), when using Legacy T the US FAA RID Rules <xref target="FAA-14CFR" format="default"/>), when using Le
ransports (such as Bluetooth 4.x).</t> gacy Transports (such as Bluetooth 4.x).</t>
<t>Under <xref target="F3411" format="default"/>, Authentication Message <t>Under <xref target="F3411" format="default"/>, Authentication Message
s are transmitted at the static rate (at least every 3 seconds). Any DRIP Authen s are transmitted at the static rate (at least every 3 seconds). Any DRIP Authen
tication Messages containing dynamic data (such as the DRIP Wrapper) MAY be sent tication Messages containing dynamic data (such as the DRIP Wrapper) <bcp14>MAY<
at the dynamic rate (at least every 1 second).</t> /bcp14> be sent at the dynamic rate (at least every 1 second).</t>
</section> </section>
<section anchor="extended-transports" numbered="true" toc="default"> <section anchor="extended-transports" numbered="true" toc="default">
<name>Extended Transports</name> <name>Extended Transports</name>
<t>Under the ASTM specification, Extended Transports of RID must use the <t>Under the ASTM specification, Extended Transports of RID must use the
Message Pack (Message Type 0xF) format for all transmissions. Under Message Pac Message Pack (Message Type 0xF) format for all transmissions. Under Message Pac
k, ASTM Messages are sent together (in Message Type order) in a single frame (up k, ASTM Messages are sent together (in Message Type order) in a single frame (up
to 9 single frame equivalent messages under Legacy Transports). Message Packs a to 9 single-frame equivalent messages under Legacy Transports). Message Packs a
re required by <xref target="F3411" format="default"/> to be sent at a rate of 1 re required by <xref target="F3411" format="default"/> to be sent at a rate of 1
per second (like dynamic messages).</t> per second (like dynamic messages).</t>
<t>Message Packs are sent only over Extended Transports that provide FEC <t>Message Packs are sent only over Extended Transports that provide FEC
. Thus, the DRIP decoders will never be presented with a Message Pack from which . Thus, the DRIP decoders will never be presented with a Message Pack from which
a constituent Authentication Page has been dropped; DRIP FEC could never provid a constituent Authentication Page has been dropped; DRIP FEC could never provid
e a benefit to a Message Pack, only consume its precious payload space. Therefor e benefit to a Message Pack, only consume its precious payload space. Therefore,
e, DRIP FEC (<xref target="fec-details" format="default"/>) MUST NOT be used in DRIP FEC (<xref target="fec-details" format="default"/>) <bcp14>MUST NOT</bcp14
Message Packs.</t> > be used in Message Packs.</t>
</section> </section>
<section anchor="drip-recommendations" numbered="true" toc="default"> <section anchor="drip-recommendations" numbered="true" toc="default">
<name>Authentication</name> <name>Authentication</name>
<t>To fulfill the requirements in <xref target="RFC9153" format="default "/>, a UA:</t> <t>To fulfill the requirements in <xref target="RFC9153" format="default "/>, a UA:</t>
<ol spacing="normal" type="1"><li>MUST: send DRIP Link (<xref target="dr <ol spacing="normal" type="1">
ip-link" format="default"/>) using the <tt>BE: Apex, RAA</tt> (partially satisfy <li><bcp14>MUST</bcp14>: send DRIP Link (<xref target="drip-link"
ing GEN-3); at least once per 5 minutes. Apex in this context is the DET prefix format="default"/>) using the <tt>BE: Apex, RAA</tt> (partially
owner</li> satisfying GEN-3); at least once per 5 minutes. Apex in this context
<li>MUST: send DRIP Link (<xref target="drip-link" format="default"/>) is the DET prefix owner.</li>
using the <tt>BE: RAA, HDA</tt> (partially satisfying GEN-3); at least once per <li><bcp14>MUST</bcp14>: send DRIP Link (<xref target="drip-link"
5 minutes</li> format="default"/>) using the <tt>BE: RAA, HDA</tt> (partially
<li>MUST: send DRIP Link (<xref target="drip-link" format="default"/>) satisfying GEN-3); at least once per 5 minutes.</li>
using the <tt>BE: HDA, UA</tt> (satisfying ID-5, GEN-1 and partially satisfying <li><bcp14>MUST</bcp14>: send DRIP Link (<xref target="drip-link"
GEN-3); at least once per minute</li> format="default"/>) using the <tt>BE: HDA, UA</tt> (satisfying ID-5,
<li>MUST: send any other DRIP Authentication Format (non-DRIP Link) wh GEN-1 and partially satisfying GEN-3); at least once per minute.</li>
ere the UA is dynamically signing data that is guaranteed to be unique, unpredic <li><bcp14>MUST</bcp14>: send any other DRIP Authentication Format
table and easily cross checked by the receiving device (satisfying ID-5, GEN-1 a (non-DRIP Link) where the UA is dynamically signing data that is
nd GEN-2); at least once per 5 seconds</li> guaranteed to be unique, unpredictable, and easily cross checked by
the receiving device (satisfying ID-5, GEN-1 and GEN-2); at least
once per 5 seconds.</li>
</ol> </ol>
<t>These four transmission requirements collectively satisfy GEN-3.</t> <t>These four transmission requirements collectively satisfy GEN-3.</t>
</section> </section>
<section anchor="operational-recommendations" numbered="true" toc="default "> <section anchor="operational-recommendations" numbered="true" toc="default ">
<name>Operational</name> <name>Operational</name>
<t>UAS operation may impact the frequency of sending DRIP Authentication <t>UAS operation may impact the frequency of sending DRIP Authentication
messages. When a UA dwells at an approximate location, and the channel is heavi Messages. When a UA dwells at an approximate location, and the channel is heavi
ly used by other devices, less frequent message authentication may be effective ly used by other devices, less frequent message authentication may be effective
(to minimize RF packet collisions) for an Observer. Contrast this with a UA tran (to minimize RF packet collisions) for an Observer. Contrast this with a UA tran
siting an area, where authenticated messages SHOULD be sufficiently frequent for siting an area, where authenticated messages <bcp14>SHOULD</bcp14> be sufficient
an Observer to have a high probability of receiving an adequate number for vali ly frequent for an Observer to have a high probability of receiving an adequate
dation during the transit.</t> number for validation during the transit.</t>
<t>A RECOMMENDED operational configuration (in alignment with <xref targ
et="drip-recommendations" format="default"/>) with reasoning can be found in <xr <t>A <bcp14>RECOMMENDED</bcp14> operational configuration (in alignment
ef target="operational-proof" format="default"/>. It consists of the following r with <xref target="drip-recommendations" format="default"/>) with rationale can
ecommendations for every second:</t> be found in <xref target="operational-proof" format="default"/>. It recommends t
he following once per second:</t>
<ul spacing="normal"> <ul spacing="normal">
<li> <li>
<t>Under Legacy Transport: <t>Under Legacy Transport:
</t> </t>
<ul spacing="normal"> <ul spacing="normal">
<li>Two sets of those ASTM Messages required by a CAA in its juris <li>Two sets of those ASTM Messages required by a CAA in its juris
diction (example: Basic ID, Location and System) and one set of other ASTM Messa diction (example: Basic ID, Location/Vector, and System) and one set of other AS
ges (example: Self ID, Operator ID)</li> TM Messages (example: Self ID, Operator ID)</li>
<li>An FEC protected DRIP Manifest enabling authentication of thos <li>An FEC-protected DRIP Manifest enabling authentication of thos
e ASTM Messages sent</li> e ASTM Messages sent</li>
<li>A single page of an FEC protected DRIP Link</li> <li>A single page of an FEC-protected DRIP Link</li>
</ul> </ul>
</li> </li>
<li> <li>
<t>Under Extended Transport: <t>Under Extended Transport:
</t> </t>
<ul spacing="normal"> <ul spacing="normal">
<li>A Message Pack of ASTM Messages (up to 4) and a DRIP Wrapper ( per <xref target="extended-wrapper" format="default"/>)</li> <li>A Message Pack of ASTM Messages (up to 4) and a DRIP Wrapper ( per <xref target="extended-wrapper" format="default"/>)</li>
<li>A Message Pack of a DRIP Link</li> <li>A Message Pack of a DRIP Link</li>
</ul> </ul>
</li> </li>
</ul> </ul>
<section anchor="wrapper-operations" numbered="true" toc="default"> <section anchor="wrapper-operations" numbered="true" toc="default">
<name>DRIP Wrapper</name> <name>DRIP Wrapper</name>
<t>If DRIP Wrappers are sent, they MUST be sent in addition to any req <t>If DRIP Wrappers are sent, they <bcp14>MUST</bcp14> be sent in addi
uired ASTM Messages in a given jurisdiction. An implementation MUST NOT send DRI tion to any required ASTM Messages in a given jurisdiction. An implementation <b
P Wrappers in place of any required ASTM Messages it may encapsulate. Thus, mess cp14>MUST NOT</bcp14> send DRIP Wrappers in place of any required ASTM Messages
ages within a Wrapper are sent twice: once in the clear and once authenticated w it may encapsulate. Thus, messages within a Wrapper are sent twice: once in the
ithin the Wrapper.</t> clear and once authenticated within the Wrapper.</t>
<t>The DRIP Wrapper has a specific use case for DRIP aware Observers. <t>The DRIP Wrapper has a specific use case for DRIP-aware Observers.
For an Observer plotting Location Messages (Message Type 0x2) on a map, display For an Observer plotting Location/Vector Messages (Message Type 0x2) on a map, d
an embedded Location Message in a DRIP Wrapper can be marked differently (e.g., isplay of an embedded Location/Vector Message in a DRIP Wrapper can be marked di
via color) to signify trust in the Location data.</t> fferently (e.g., via color) to signify trust in the Location/Vector data.</t>
</section> </section>
<section anchor="trust-assessment" numbered="true" toc="default"> <section anchor="trust-assessment" numbered="true" toc="default">
<name>UAS RID Trust Assessment</name> <name>UAS RID Trust Assessment</name>
<t>As described in <xref target="rid-trust" format="default"/>, the Ob <t>As described in <xref target="rid-trust" format="default"/>, the Ob
server MUST perform validation of the data being received in Broadcast RID. This server <bcp14>MUST</bcp14> perform validation of the data being received in Broa
is because trust in a key is different from trust that an observed UA possesses dcast RID. This is because trust in a key is different from trust that an observ
that key.</t> ed UA possesses that key.</t>
<t>A chain of DRIP Links provides trust in a key. A message containing <t>A chain of DRIP Links provides trust in a key. A message, signed by
rapidly changing, not predictable far in advance (relative to typical operation that key, containing data that changes rapidly and is not predictable far in ad
al flight times) that can be validated by Observers, signed by that key, provide vance (relative to typical operational flight times) but that can be validated b
s trust that some agent with access to that data also possesses that key. If the y Observers, provides trust that some agent with access to that data also posses
validation involves correlating physical world observations of the UA with clai ses that key. If the validation involves correlating physical world observations
ms in that data, then the probability is high that the observed UA is (or is col of the UA with claims in that data, then the probability is high that the obser
laborating with or observed in real time by) the agent with the key.</t> ved UA is (or is collaborating with or observed in real time by) the agent with
<t>After signature verification of any DRIP Authentication Message con the key.</t>
taining UAS RID information elements (e.g., DRIP Wrapper <xref target="drip-wrap <t>After signature verification of any DRIP Authentication Message con
per" format="default"/>) the Observer MUST use other sources of information to c taining UAS RID information elements (e.g., DRIP Wrapper <xref target="drip-wrap
orrelate against and perform validation. An example of another source of informa per" format="default"/>) the Observer <bcp14>MUST</bcp14> use other sources of i
tion is a visual confirmation of the UA position.</t> nformation to correlate against and perform validation. An example of another so
<t>When correlation of these different data streams does not match in urce of information is a visual confirmation of the UA position.</t>
acceptable thresholds, the data MUST be rejected as if the signature failed to v <t>When correlation of these different data streams does not match in
alidate. Acceptable thresholds limits and what happens after such a rejection ar acceptable thresholds, the data <bcp14>MUST</bcp14> be rejected as if the signat
e out of scope for this document.</t> ure failed to validate. Acceptable threshold limits and what happens after such
a rejection are out of scope for this document.</t>
</section> </section>
</section> </section>
</section> </section>
<section anchor="req-sum" numbered="true" toc="default"> <section anchor="req-sum" numbered="true" toc="default">
<name>Summary of Addressed DRIP Requirements</name> <name>Summary of Addressed DRIP Requirements</name>
<t>The following <xref target="RFC9153" format="default"/> requirements ar <t>The following requirements as defined in <xref target="RFC9153" format=
e addressed in this document:</t> "default"/> are addressed in this document:</t>
<t>ID-5: Non-spoofability</t> <dl>
<ul empty="true" spacing="normal"> <dt>ID-5:</dt><dd><t>Non-spoofability</t>
<li>Addressed using the DRIP Wrapper (<xref target="drip-wrapper" format <t>Addressed using the DRIP Wrapper (<xref target="drip-wrapper" format=
="default"/>), DRIP Manifest (<xref target="drip-manifest" format="default"/>) o "default"/>), DRIP Manifest (<xref target="drip-manifest" format="default"/>), o
r DRIP Frame (<xref target="drip-frame" format="default"/>).</li> r DRIP Frame (<xref target="drip-frame" format="default"/>).</t></dd>
</ul>
<t>GEN-1: Provable Ownership</t> <dt>GEN-1:</dt><dd><t>Provable Ownership</t>
<ul empty="true" spacing="normal">
<li>Addressed using the DRIP Link (<xref target="drip-link" format="defa <t>Addressed using the DRIP Link (<xref target="drip-link" format="defau
ult"/>) and DRIP Wrapper (<xref target="drip-wrapper" format="default"/>), DRIP lt"/>) and DRIP Wrapper (<xref target="drip-wrapper" format="default"/>), DRIP M
Manifest (<xref target="drip-manifest" format="default"/>) or DRIP Frame (<xref anifest (<xref target="drip-manifest" format="default"/>), or DRIP Frame (<xref
target="drip-frame" format="default"/>).</li> target="drip-frame" format="default"/>).</t></dd>
</ul>
<t>GEN-2: Provable Binding</t> <dt>GEN-2:</dt><dd><t>Provable Binding</t>
<ul empty="true" spacing="normal"> <t>Addressed using the DRIP Wrapper (<xref target="drip-wrapper" format=
<li>Addressed using the DRIP Wrapper (<xref target="drip-wrapper" format "default"/>), DRIP Manifest (<xref target="drip-manifest" format="default"/>) or
="default"/>), DRIP Manifest (<xref target="drip-manifest" format="default"/>) o DRIP Frame (<xref target="drip-frame" format="default"/>).</t></dd>
r DRIP Frame (<xref target="drip-frame" format="default"/>).</li>
</ul> <dt>GEN-3:</dt><dd><t>Provable Registration</t>
<t>GEN-3: Provable Registration</t> <t>Addressed using the DRIP Link (<xref target="drip-link" format="defau
<ul empty="true" spacing="normal"> lt"/>).</t></dd></dl>
<li>Addressed using the DRIP Link (<xref target="drip-link" format="defa
ult"/>).</li>
</ul>
</section> </section>
<section anchor="iana-considerations" numbered="true" toc="default"> <section anchor="iana-considerations" numbered="true" toc="default">
<name>IANA Considerations</name> <name>IANA Considerations</name>
<section anchor="iana-drip-registry" numbered="true" toc="default"> <section anchor="iana-drip-registry" numbered="true" toc="default">
<name>IANA DRIP Registry</name> <name>IANA DRIP Registry</name>
<t>This document requests two new registries, for DRIP SAM Type and DRIP <t>IANA has created the "DRIP SAM Types" and "DRIP Frame Types" registri
Frame Type, under the <eref target="https://www.iana.org/assignments/drip/drip. es within the <eref target="https://www.iana.org/assignments/drip">"Drone Remote
xhtml">DRIP registry group</eref>.</t> ID Protocol" registry group</eref>.</t>
<dl newline="false" spacing="normal"> <dl newline="true" spacing="normal">
<dt>DRIP SAM Type:</dt> <dt>DRIP SAM Types:</dt>
<dd> <dd><t>This registry is a mirror for SAM Types containing the subset o
This registry is a mirror for SAM Types containing the subset of allocations u f
sed by DRIP Authentication Messages. Future additions MUST be done through ASTM' allocations used by DRIP Authentication Messages. Future additions
s designated registrar which at the time of publication of this RFC is ICAO <xre <bcp14>MUST</bcp14> be done through ASTM's designated registrar,
f target="ASTM-Remote-ID" format="default"/>. Additions for DRIP will be coordin which is ICAO <xref target="ASTM-Remote-ID" format="default"/> at the
ated by IANA and the ASTM designated registrar before final publication as Stand time of publication of this RFC (2024). The registration procedure for DRIP (onl
ards Track RFCs. The following values have been allocated to the IETF and are de y) SAM Types is Standards Action <xref target="RFC8126"/>.
fined here:</dd> Requests for new DRIP SAM Type registrations will be coordinated by IANA and t
</dl> he
ASTM-designated registrar of all SAM Types before being documented in Standard
s Track RFCs. The following values have
been allocated to the IETF:</t>
<table align="center"> <table align="center">
<name>DRIP SAM Types</name> <name>DRIP SAM Types</name>
<thead> <thead>
<tr> <tr>
<th align="left">SAM Type</th> <th align="left">SAM Type</th>
<th align="left">Name</th> <th align="left">Name</th>
<th align="left">Description</th> <th align="left">Description</th>
</tr> </tr>
</thead> </thead>
<tbody> <tbody>
skipping to change at line 874 skipping to change at line 992
<td align="left">0x03</td> <td align="left">0x03</td>
<td align="left">DRIP Manifest</td> <td align="left">DRIP Manifest</td>
<td align="left">Authenticate hashes of ASTM Messages</td> <td align="left">Authenticate hashes of ASTM Messages</td>
</tr> </tr>
<tr> <tr>
<td align="left">0x04</td> <td align="left">0x04</td>
<td align="left">DRIP Frame</td> <td align="left">DRIP Frame</td>
<td align="left">Format for future DRIP authentication</td> <td align="left">Format for future DRIP authentication</td>
</tr> </tr>
</tbody> </tbody>
</table> </table></dd>
<dl newline="false" spacing="normal">
<dt>DRIP Frame Type:</dt> <dt>DRIP Frame Types:</dt>
<dd> <dd><t>This 8-bit value registry is for Frame Types in DRIP Frame
This 8-bit valued registry is for Frame Types in DRIP Frame Authentication Mes Authentication Messages. Future additions to this registry are to be
sages. Future additions to this registry are to be made through Expert Review (S made through Expert Review (<xref target="RFC8126"
ection 4.5 of <xref target="RFC8126" format="default"/>) for the values of 0x01 sectionFormat="of" section="4.5"/>) for values 0x01 to 0x9F
to 0x9F and First Come, First Served (Section 4.4 of <xref target="RFC8126" form and First Come First Served (<xref target="RFC8126"
at="default"/>) for values 0xA0 to 0xEF. The following values are defined:</dd> sectionFormat="of" section="4.4"/>) for values 0xA0 to 0xEF. The
</dl> following values are defined:</t>
<table align="center"> <table align="center">
<name>DRIP Frame Types</name> <name>DRIP Frame Types</name>
<thead> <thead>
<tr> <tr>
<th align="left">Frame Type</th> <th align="left">Frame Type</th>
<th align="left">Name</th> <th align="left">Name</th>
<th align="left">Description</th> <th align="left">Description</th>
</tr> </tr>
</thead> </thead>
<tbody> <tbody>
<tr> <tr>
<td align="left">0x00</td> <td align="left">0x00</td>
<td align="left">Reserved</td> <td align="left">Reserved</td>
<td align="left">Reserved</td> <td align="left">Reserved</td>
</tr> </tr>
<tr> <tr>
<td align="left">0x01 - 0x9F</td> <td align="left">0x01 - 0xEF</td>
<td align="left">Reserved</td> <td align="left">Unassigned</td>
<td align="left">Reserved: Expert Review</td> <td align="left"></td>
</tr>
<tr>
<td align="left">0xA0 - 0xEF</td>
<td align="left">Reserved</td>
<td align="left">Reserved: First Come, First Served</td>
</tr>
<tr>
<td align="left">0xF0 - 0xFF</td>
<td align="left">Experimental</td>
<td align="left">Experimental Use</td>
</tr> </tr>
<tr>
<td align="left">0xF0-0xFF</td>
<td align="left">Experimental</td>
<td align="left">Reserved for Experimental Use</td>
</tr>
</tbody> </tbody>
</table> </table>
</dd></dl>
<t>Criteria that should be applied by the designated experts includes de termining whether the proposed registration duplicates existing functionality an d whether the registration description is clear and fits the purpose of this reg istry.</t> <t>Criteria that should be applied by the designated experts includes de termining whether the proposed registration duplicates existing functionality an d whether the registration description is clear and fits the purpose of this reg istry.</t>
<t>Registration requests MUST be sent to <eref target="mailto:drip-reg-r eview@ietf.org">drip-reg-review@ietf.org</eref> and be evaluated within a three- week review period on the advice of one or more designated experts. Within that review period, the designated experts will either approve or deny the registrati on request, and communicate their decision to the review list and IANA. Denials should include an explanation and, if applicable, suggestions to successfully re gister the DRIP Frame Type.</t> <t>Registration requests <bcp14>MUST</bcp14> be sent to <eref target="ma ilto:drip-reg-review@ietf.org">drip-reg-review@ietf.org</eref> and be evaluated by one or more designated experts within a three-week review period. Within that review period, the designated experts will either approve or deny the registrat ion request, and communicate their decision to the review list and IANA. Denials should include an explanation and, if applicable, suggestions to successfully r egister the DRIP Frame Type.</t>
<t>Registration requests that are undetermined for a period longer than 28 days can be brought to the IESG's attention for resolution.</t> <t>Registration requests that are undetermined for a period longer than 28 days can be brought to the IESG's attention for resolution.</t>
</section> </section>
</section> </section>
<section anchor="security-considerations" numbered="true" toc="default"> <section anchor="security-considerations" numbered="true" toc="default">
<name>Security Considerations</name> <name>Security Considerations</name>
<section anchor="replay-attacks" numbered="true" toc="default"> <section anchor="replay-attacks" numbered="true" toc="default">
<name>Replay Attacks</name> <name>Replay Attacks</name>
<t><xref target="F3411" format="default"/> (regardless of transport) lac <t><xref target="F3411" format="default"/> (regardless of transport) lac
ks replay protection, as it more fundamentally lacks fully specified authenticat ks replay protection, as it more fundamentally lacks fully specified authenticat
ion. An attacker can spoof the UA sender MAC address and UAS ID, replaying (with ion. An attacker can spoof the UA sender MAC address and UAS ID, replaying (with
or without modification) previous genuine messages, and/or crafting entirely ne or without modification) previous genuine messages, and/or crafting entirely ne
w messages. Using DRIP in <xref target="F3411" format="default"/> Authentication w messages. Using DRIP in <xref target="F3411" format="default"/> Authentication
message framing enables verification that messages were signed with registered Message framing enables verification that messages were signed with registered
keys, but when naively used may be vulnerable to replay attacks. Technologies su keys, but when naively used may be vulnerable to replay attacks. Technologies su
ch as Single Emitter Identification can detect such attacks, but are not readily ch as Single Emitter Identification can detect such attacks, but they are not re
available and can be prohibitively expensive, especially for typical Observer d adily available and can be prohibitively expensive, especially for typical Obser
evices such as smartphones.</t> ver devices such as smartphones.</t>
<t>Replay attack detection using DRIP requires Observer devices to combi
ne information from multiple messages and sources other than Broadcast RID. A co <!-- [rfced] We are having trouble parsing this sentence. Please review.
mplete chain of Link messages (<xref target="drip-link" format="default"/>), fro
m an Endorsement root of trust to the claimed sender, must be collected and veri Original:
fied by the Observer device to provide trust in a key. Successful signature veri Successful signature verification, using that key, of a Wrapper
fication, using that key, of a Wrapper (<xref target="drip-wrapper" format="defa (Section 4.3) or Manifest (Section 4.4) message, authenticating
ult"/>) or Manifest (<xref target="drip-manifest" format="default"/>) message, a content that is nonce-like, provides trust that the sender actually
uthenticating content that is nonce-like, provides trust that the sender actuall possesses that key.
y possesses that key.</t>
<t>By "nonce-like" is meant data that is unique, not accurately predicta Perhaps:
ble long in advance, and readily validated by the Observer. This is described in Using that key, successful signature verification of a Wrapper
<xref target="drip-recommendations" format="default"/> (requirement 4) and <xre (Section 4.3) or Manifest (Section 4.4) message and authentication of
f target="ua-attestation" format="default"/>. The <xref target="F3411" format="d content that is nonce-like provides trust that the sender actually
efault"/> Location message reporting precise UA position and velocity at a preci possesses that key.
se very recent time, to be checked by the Observer against visual observations o
f the UA within RF and thus typically visual Line Of Sight is the recommended fo Authors NEW text:
rm of this data. For specification of the foregoing, see <xref target="rid-trust
" format="default"/> and <xref target="trust-assessment" format="default"/>.</t> Successful signature verification, using that public key, of a Wrapper
<t>Messages that pass signature verification with trusted keys could sti (Section 4.3) or Manifest (Section 4.4) message, authenticating
ll be replays if they contain only static information (e.g., Broadcast Endorseme content that is nonce-like, provides trust that the sender actually
nts (<xref target="drip-link" format="default"/>), <xref target="F3411" format=" possesses the corresponding private key.
default"/> Basic ID or <xref target="F3411" format="default"/> Operator ID) or i
nformation that cannot be readily validated (e.g., <xref target="F3411" format=" Reversing the order of the first two phrases in this sentence does not read as l
default"/> Self-ID). Replay of Link messages is harmless (unless sent so frequen ogically to me (the original phrasing proceeds from the general to the specific)
tly as to cause RF data link congestion) and indeed can increase the likelihood , but if the meaning is actually unclear as I have phrased it, I can live with t
of an Observer device collecting an entire trust chain in a short time window. R he reversal.
eplay of other messages (<xref target="F3411" format="default"/> Basic ID, <xref
target="F3411" format="default"/> Operator ID, or <xref target="F3411" format=" [rfced] It is still unclear to us how "authenticating content that is nonce-like
default"/> Self-ID) remains a vulnerability, unless they are combined with messa " relates to rest of the sentence. Please clarify.
ges containing nonce-like data (<xref target="F3411" format="default"/> Location
or <xref target="F3411" format="default"/> System) in a Wrapper or Manifest. Fo Perhaps:
r specification of this last requirement, see <xref target="block-hashes" format Successful signature verification (using that public key) of a Wrapper
="default"/>.</t> or Manifest message, which authenticates
content that is nonce-like, provides trust that the sender actually
possesses the corresponding private key.
-->
<t>Replay attack detection using DRIP requires Observer devices to combi
ne information from multiple messages and sources other than Broadcast RID. A co
mplete chain of Link messages (<xref target="drip-link" format="default"/>) from
an Endorsement root of trust to the claimed sender must be collected and verifi
ed by the Observer device to provide trust in a key.
Successful signature verification, using that public key, of a Wrapper
(<xref target="drip-wrapper" format="default"/>) or Manifest (<xref target="dr
ip-manifest"/>) message, authenticating
content that is nonce-like, provides trust that the sender actually
possesses the corresponding private key.</t>
<t>The term "nonce-like" describes data that is unique, changes frequent
ly,
is not accurately predictable long in advance, and is easily validated (i.e.,
can be checked quickly at low computational cost using readily available
data) by the Observer. A Location/Vector Message is an obvious choice.
This is described in <xref target="drip-recommendations" format="default"/> (req
uirement 4) and <xref target="ua-attestation" format="default"/>. The Location/V
ector Message <xref target="F3411" format="default"/> reporting precise UA posit
ion and velocity at a precise and very recent time is to be checked by the Obser
ver against visual observations of the UA within RF. Thus, Visual Line of Sight
is typically the recommended form of this data. For specification of the foregoi
ng, see Sections <xref target="rid-trust" format="counter"/> and <xref target="t
rust-assessment" format="counter"/>.</t>
<t>Messages that pass signature verification with trusted keys could sti
ll be replays if they contain only static information (e.g., Broadcast Endorseme
nts (<xref target="drip-link" format="default"/>), <xref target="F3411" format="
default"/> Basic ID or <xref target="F3411" format="default"/> Operator ID), or
information that cannot be readily validated (e.g., <xref target="F3411" format=
"default"/> Self-ID). Replay of Link messages is harmless (unless sent so freque
ntly as to cause RF data link congestion) and indeed can increase the likelihood
of an Observer device collecting an entire trust chain in a short time window.
Replay of other messages (<xref target="F3411" format="default"/> Basic ID, <xre
f target="F3411" format="default"/> Operator ID, or <xref target="F3411" format=
"default"/> Self-ID) remains a vulnerability, unless they are combined with mess
ages containing nonce-like data (<xref target="F3411" format="default"/> Locatio
n/Vector or <xref target="F3411" format="default"/> System) in a Wrapper or Mani
fest. For specification of this last requirement, see <xref target="block-hashes
" format="default"/>.</t>
</section> </section>
<section anchor="wrapper-vs-manifest" numbered="true" toc="default"> <section anchor="wrapper-vs-manifest" numbered="true" toc="default">
<name>Wrapper vs Manifest</name> <name>Wrapper vs Manifest</name>
<t>Implementations have a choice on using Wrapper (<xref target="drip-wr <t>Implementations have a choice of using Wrapper (<xref target="drip-wr
apper" format="default"/>), Manifest (<xref target="drip-manifest" format="defau apper" format="default"/>), Manifest (<xref target="drip-manifest" format="defau
lt"/>), or a combination to satisfy the 4th requirement in <xref target="drip-re lt"/>), or a combination to satisfy the fourth requirement in <xref target="drip
commendations" format="default"/>.</t> -recommendations" format="default"/>.</t>
<t>Wrapper is an attached signature of the full content of one or more < <t>
xref target="F3411" format="default"/> messages, providing strong authentication Wrapper is an attached signature on the full content of one or more
. However, the size limitation means it can not support such signatures over oth <xref target="F3411"/> messages, providing strong authentication.
er Authentication Messages, thus it can not provide a direct binding to any part Wrapper is an attached signature of the full content of one or more <xref target
of the trust chain (<xref target="rid-trust" format="default"/> and <xref targe ="F3411" format="default"/> messages, providing strong authentication.
t="trust-assessment" format="default"/>).</t>
<t>Manifest explicitly provides the binding of the last link in the trus However, the size limitation means it cannot support such signatures over other
t chain (with the inclusion of the hash of the Link containing <tt>BE: HDA, UA</ Authentication Messages; thus, it cannot provide a direct binding to any part of
tt>). The use of hashes and their length also allows for a larger (11 vs 4) numb the trust chain (Sections <xref target="rid-trust" format="counter"/> and <xref
er of any <xref target="F3411" format="default"/> messages to be authenticated, target="trust-assessment" format="counter"/>).</t>
making it more efficient compared to the Wrapper. However, the detached signatur <t>Manifest explicitly provides the binding of the last link in the trus
e requires additional Observer overhead in storing and comparing hashes of recei t chain (with the inclusion of the hash of the Link containing <tt>BE: HDA, UA</
ved messages (some that may not be received) of those in a Manifest.</t> tt>). The use of hashes and their length also allows for a larger number (11 vs
<t><xref target="operational-proof" format="default"/> contains a breakd 4) of <xref target="F3411" format="default"/> messages to be authenticated, maki
own of frame counts and an example of a schedule using both Manifest and Wrapper ng it more efficient compared to the Wrapper. However, the detached signature re
. Typical operation may see (as an example) 2x Basic ID, 2x Location, 2x System, quires additional Observer overhead in storing and comparing hashes of received
1x Operator ID and 1x Self ID broadcast per second to comply with jurisdiction messages (some of which may not be received) with those in a Manifest.</t>
mandates. Each of these messages are a single frame in size. A Link message is 8 <t><xref target="operational-proof" format="default"/> contains a breakd
frames long (including FEC). This is a base frame count of <strong>16 frames</s own of frame counts and an example of a schedule using both Manifest and Wrapper
trong>.</t> . Typical operation may see (as an example) 2x Basic ID, 2x Location/Vector, 2x
<t>When Wrapper is used, up to 4 of the previous messages (except the Li System, 1x Operator ID and 1x Self ID broadcast per second to comply with jurisd
nk) can be authenticated. For this comparison, we will sign all the messages we iction mandates. Each of these messages is a single frame in size. A Link messag
can in two Wrappers. This results in <em>20 frames</em> (with FEC). Due to not b e is 8 frames long (including FEC). This is a base frame count of <strong>16 fra
eing able to fit, the Link message is left unauthenticated. The total frame coun mes</strong>.</t>
t using Wrappers is <strong>36 frames</strong> (wrapper frame count + base frame <t>When Wrapper is used, up to four of the previous messages (except the
count).</t> Link) can be authenticated. For this comparison, we will sign all the messages
<t>When Manifest is used, up to 10 previous messages can be authenticate we can in two Wrappers. This results in <em>20 frames</em> (with FEC). Due to si
d. For this example all messages (8) are hashed (including the Link) resulting i ze constraints, the Link message is left unauthenticated. The total frame count
n a single Manifest that is <em>9 frames</em> (with FEC). The total frame count using Wrappers is <strong>36 frames</strong> (wrapper frame count + base frame c
using Manifest is <strong>25 frames</strong> (manifest frame count + base frame ount).</t>
count).</t> <t>When Manifest is used, up to 10 previous messages can be authenticate
d. For this example, all messages (8) are hashed (including the Link) resulting
in a single Manifest that is <em>9 frames</em> (with FEC). The total frame count
using Manifest is <strong>25 frames</strong> (manifest frame count + base frame
count).</t>
</section> </section>
<section anchor="vna-timestamp-offsets-for-drip-authentication-formats" nu mbered="true" toc="default"> <section anchor="vna-timestamp-offsets-for-drip-authentication-formats" nu mbered="true" toc="default">
<name>VNA Timestamp Offsets for DRIP Authentication Formats</name> <name>VNA Timestamp Offsets for DRIP Authentication Formats</name>
<t>Note the discussion of VNA Timestamp offsets here is in the context o <t>Note the discussion of VNA Timestamp offsets here is in the context o
f the DRIP Wrapper (<xref target="drip-wrapper" format="default"/>), DRIP Manife f the DRIP Wrapper (<xref target="drip-wrapper" format="default"/>), DRIP Manife
st (<xref target="drip-manifest" format="default"/>), and DRIP Frame (<xref targ st (<xref target="drip-manifest" format="default"/>), and DRIP Frame (<xref targ
et="drip-frame" format="default"/>). For DRIP Link (<xref target="drip-link" for et="drip-frame" format="default"/>). For DRIP Link (<xref target="drip-link" for
mat="default"/>) these offsets are set by the DIME and have their own set of con mat="default"/>), these offsets are set by the DIME and have their own set of co
siderations in <xref target="drip-registries" format="default"/>.</t> nsiderations in <xref target="I-D.ietf-drip-registries" format="default"/>.</t>
<t>The offset of the <tt>VNA Timestamp by UA</tt> is one that needs care <t>The offset of the <tt>VNA Timestamp by UA</tt> is one that needs care
ful consideration for any implementation. The offset should be shorter than any ful consideration for any implementation. The offset should be shorter than any
given flight duration (typically less than an hour) but be long enough to be rec given flight duration (typically less than an hour) but be long enough to be rec
eived and processed by Observers (larger than a few seconds). It is recommended eived and processed by Observers (larger than a few seconds). It is recommended
that 3-5 minutes should be sufficient to serve this purpose in any scenario, but that 3-5 minutes should be sufficient to serve this purpose in any scenario, but
is not limited by design.</t> it is not limited by design.</t>
</section> </section>
<section anchor="dns-security" numbered="true" toc="default"> <section anchor="dns-security" numbered="true" toc="default">
<name>DNS Security in DRIP</name> <name>DNS Security in DRIP</name>
<t>As stated in <xref target="protocol-desc" format="default"/> specific <t>As stated in <xref target="protocol-desc" format="default"/> specific
ation of particular DNS security options, transports, etc. is outside the scope ation of particular DNS security options, transports, etc. is outside the scope
of this document. <xref target="drip-registries" format="default"/> is the main of this document.
specification for DNS operations in DRIP and as such will specify DRIP usage of The main specification for DNS operations in DRIP <xref target="I-D.ietf-drip-
best common practices for security (such as <xref target="RFC9364" format="defau registries" format="default"/>
lt"/>).</t> will specify applicable best common security practices
(e.g., from <xref target="RFC9364"/>).</t>
</section> </section>
</section> </section>
<section anchor="acknowledgments" numbered="true" toc="default">
<name>Acknowledgments</name>
<ul spacing="normal">
<li>Ryan Quigley, James Mussi and Joseph Stanton of AX Enterprize, LLC f
or early prototyping to find holes in the draft specifications</li>
<li>Carsten Bormann for the simple approach of using bit-column-wise par
ity for erasure (dropped frame) FEC</li>
<li>Soren Friis for pointing out that Wi-Fi implementations would not al
ways give access to the MAC Address, originally used in calculation of the hashe
s for DRIP Manifest. Also, for confirming that Message Packs (0xF) can only carr
y up to 9 ASTM frames worth of data (9 Authentication pages)</li>
<li>Gabriel Cox (chair of the working group that produced <xref target="
F3411" format="default"/>) in reviewing the specification for the SAM Type reque
st as the ASTM Designated Expert</li>
<li>Mohamed Boucadair (Document Shepherd) for his many patches and comme
nts</li>
<li>Eric Vyncke (DRIP AD) for his guidance through the documents path to
publication</li>
<li>
<t>Thanks to the following reviewers:
</t>
<ul spacing="normal">
<li>Rick Salz (secdir)</li>
<li>Matt Joras (genart)</li>
<li>Di Ma (dnsdir)</li>
<li>Gorry Fairhurst (tsvart)</li>
<li>Carlos Bernardos (intdir)</li>
<li>Behcet Sarikaya (iotdir)</li>
<li>Martin Duke (IESG)</li>
<li>Roman Danyliw (IESG)</li>
<li>Murray Kucherawy (IESG)</li>
<li>Erik Kline (IESG)</li>
<li>Warren Kumari (IESG)</li>
<li>Paul Wouters (IESG)</li>
</ul>
</li>
</ul>
</section>
</middle> </middle>
<back> <back>
<displayreference target="I-D.ietf-drip-registries" to="DRIP-REG"/>
<references> <references>
<name>References</name> <name>References</name>
<references> <references>
<name>Normative References</name> <name>Normative References</name>
<reference anchor="RFC9153" target="https://www.rfc-editor.org/info/rfc9
153"> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.91
<front> 53.xml"/>
<title>Drone Remote Identification Protocol (DRIP) Requirements and <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.93
Terminology</title> 74.xml"/>
<author fullname="S. Card" initials="S." role="editor" surname="Card <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.94
"/> 34.xml"/>
<author fullname="A. Wiethuechter" initials="A." surname="Wiethuecht
er"/>
<author fullname="R. Moskowitz" initials="R." surname="Moskowitz"/>
<author fullname="A. Gurtov" initials="A." surname="Gurtov"/>
<date month="February" year="2022"/>
<abstract>
<t>This document defines terminology and requirements for solution
s produced by the Drone Remote Identification Protocol (DRIP) Working Group. The
se solutions will support Unmanned Aircraft System Remote Identification and tra
cking (UAS RID) for security, safety, and other purposes (e.g., initiation of id
entity-based network sessions supporting UAS applications). DRIP will facilitate
use of existing Internet resources to support RID and to enable enhanced relate
d services, and it will enable online and offline verification that RID informat
ion is trustworthy.</t>
</abstract>
</front>
<seriesInfo name="RFC" value="9153"/>
<seriesInfo name="DOI" value="10.17487/RFC9153"/>
</reference>
<reference anchor="RFC9374" target="https://www.rfc-editor.org/info/rfc9
374">
<front>
<title>DRIP Entity Tag (DET) for Unmanned Aircraft System Remote ID
(UAS RID)</title>
<author fullname="R. Moskowitz" initials="R." surname="Moskowitz"/>
<author fullname="S. Card" initials="S." surname="Card"/>
<author fullname="A. Wiethuechter" initials="A." surname="Wiethuecht
er"/>
<author fullname="A. Gurtov" initials="A." surname="Gurtov"/>
<date month="March" year="2023"/>
<abstract>
<t>This document describes the use of Hierarchical Host Identity T
ags (HHITs) as self-asserting IPv6 addresses, which makes them trustable identif
iers for use in Unmanned Aircraft System Remote Identification (UAS RID) and tra
cking.</t>
<t>Within the context of RID, HHITs will be called DRIP Entity Tag
s (DETs). HHITs provide claims to the included explicit hierarchy that provides
registry (via, for example, DNS, RDAP) discovery for third-party identifier endo
rsement.</t>
<t>This document updates RFCs 7401 and 7343.</t>
</abstract>
</front>
<seriesInfo name="RFC" value="9374"/>
<seriesInfo name="DOI" value="10.17487/RFC9374"/>
</reference>
<reference anchor="RFC9434" target="https://www.rfc-editor.org/info/rfc9
434">
<front>
<title>Drone Remote Identification Protocol (DRIP) Architecture</tit
le>
<author fullname="S. Card" initials="S." surname="Card"/>
<author fullname="A. Wiethuechter" initials="A." surname="Wiethuecht
er"/>
<author fullname="R. Moskowitz" initials="R." surname="Moskowitz"/>
<author fullname="S. Zhao" initials="S." role="editor" surname="Zhao
"/>
<author fullname="A. Gurtov" initials="A." surname="Gurtov"/>
<date month="July" year="2023"/>
<abstract>
<t>This document describes an architecture for protocols and servi
ces to support Unmanned Aircraft System Remote Identification and tracking (UAS
RID), plus UAS-RID-related communications. This architecture adheres to the requ
irements listed in the Drone Remote Identification Protocol (DRIP) Requirements
document (RFC 9153).</t>
</abstract>
</front>
<seriesInfo name="RFC" value="9434"/>
<seriesInfo name="DOI" value="10.17487/RFC9434"/>
</reference>
<reference anchor="F3411" target="https://www.astm.org/f3411-22a.html"> <reference anchor="F3411" target="https://www.astm.org/f3411-22a.html">
<front> <front>
<title>Standard Specification for Remote ID and Tracking</title> <title>Standard Specification for Remote ID and Tracking</title>
<author> <author>
<organization>ASTM International</organization> <organization>ASTM International</organization>
</author> </author>
<date year="2022" month="July"/> <date year="2022" month="July"/>
</front> </front>
<seriesInfo name="ASTM" value="F3411-22A"/> <seriesInfo name="ASTM" value="F3411-22A"/>
<seriesInfo name="DOI" value="10.1520/F3411-22A"/> <seriesInfo name="DOI" value="10.1520/F3411-22A"/>
</reference> </reference>
<reference anchor="RFC2119" target="https://www.rfc-editor.org/info/rfc2
119"> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.21
<front> 19.xml"/>
<title>Key words for use in RFCs to Indicate Requirement Levels</tit <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.81
le> 74.xml"/>
<author fullname="S. Bradner" initials="S." surname="Bradner"/>
<date month="March" year="1997"/>
<abstract>
<t>In many standards track documents several words are used to sig
nify the requirements in the specification. These words are often capitalized. T
his document defines these words as they should be interpreted in IETF documents
. This document specifies an Internet Best Current Practices for the Internet Co
mmunity, and requests discussion and suggestions for improvements.</t>
</abstract>
</front>
<seriesInfo name="BCP" value="14"/>
<seriesInfo name="RFC" value="2119"/>
<seriesInfo name="DOI" value="10.17487/RFC2119"/>
</reference>
<reference anchor="RFC8174" target="https://www.rfc-editor.org/info/rfc8
174">
<front>
<title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</ti
tle>
<author fullname="B. Leiba" initials="B." surname="Leiba"/>
<date month="May" year="2017"/>
<abstract>
<t>RFC 2119 specifies common key words that may be used in protoco
l specifications. This document aims to reduce the ambiguity by clarifying that
only UPPERCASE usage of the key words have the defined special meanings.</t>
</abstract>
</front>
<seriesInfo name="BCP" value="14"/>
<seriesInfo name="RFC" value="8174"/>
<seriesInfo name="DOI" value="10.17487/RFC8174"/>
</reference>
<reference anchor="NIST.SP.800-185" target="https://nvlpubs.nist.gov/nis tpubs/SpecialPublications/NIST.SP.800-185.pdf"> <reference anchor="NIST.SP.800-185" target="https://nvlpubs.nist.gov/nis tpubs/SpecialPublications/NIST.SP.800-185.pdf">
<front> <front>
<title>SHA-3 derived functions: cSHAKE, KMAC, TupleHash and Parallel <title>SHA-3 Derived Functions: cSHAKE, KMAC, TupleHash and Parallel
Hash</title> Hash</title>
<author fullname="John Kelsey" surname="Kelsey"> <author fullname="John Kelsey" surname="Kelsey"/>
<organization>Information Technology Laboratory</organization> <author fullname="Shu-jen Chang" surname="Chang"/>
</author> <author fullname="Ray Perlner" surname="Perlner"/>
<author fullname="Shu-jen Change" surname="Change"> <date month="December" year="2016"/>
<organization>Information Technology Laboratory</organization>
</author>
<author fullname="Ray Perlner" surname="Perlner">
<organization>Information Technology Laboratory</organization>
</author>
<author>
<organization abbrev="NIST">National Institute of Standards and Te
chnology</organization>
<address>
<postal>
<country>US</country>
<city>Gaithersburg</city>
</postal>
</address>
</author>
<date month="December" year="2016"/>
</front> </front>
<seriesInfo name="NIST Special Publications (General)" value="800-185" /> <seriesInfo name="NIST Special Publication" value="800-185"/>
<seriesInfo name="DOI" value="10.6028/NIST.SP.800-185"/> <seriesInfo name="DOI" value="10.6028/NIST.SP.800-185"/>
</reference> </reference>
</references> </references>
<references> <references>
<name>Informative References</name> <name>Informative References</name>
<reference anchor="drip-registries" target="https://datatracker.ietf.org
/doc/html/draft-ietf-drip-registries-14">
<front>
<title>DRIP Entity Tag (DET) Identity Management Architecture</title
>
<author fullname="Adam Wiethuechter" initials="A." surname="Wiethuec
hter">
<organization>AX Enterprize, LLC</organization>
</author>
<author fullname="Jim Reid" initials="J." surname="Reid">
<organization>RTFM llp</organization>
</author>
<date day="4" month="December" year="2023"/>
<abstract>
<t> This document describes the high level architecture for the
registration and discovery of DRIP Entity Tags (DETs) using DNS.
Discovery of DETs and their artifacts are through DRIP specific DNS
structures and standard DNS methods. A general overview of the
interfaces required between involved components is described in this
document with future supporting documents giving technical
specifications.
</t> <!-- [I-D.ietf-drip-registries] IESG State: I-D Exists -->
</abstract> <xi:include href="https://bib.ietf.org/public/rfc/bibxml3/reference.I-D.i
</front> etf-drip-registries.xml"/>
<seriesInfo name="Internet-Draft" value="draft-ietf-drip-registries-14
"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.81
</reference> 26.xml"/>
<reference anchor="RFC8126" target="https://www.rfc-editor.org/info/rfc8 <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.93
126"> 64.xml"/>
<front>
<title>Guidelines for Writing an IANA Considerations Section in RFCs
</title>
<author fullname="M. Cotton" initials="M." surname="Cotton"/>
<author fullname="B. Leiba" initials="B." surname="Leiba"/>
<author fullname="T. Narten" initials="T." surname="Narten"/>
<date month="June" year="2017"/>
<abstract>
<t>Many protocols make use of points of extensibility that use con
stants to identify various protocol parameters. To ensure that the values in the
se fields do not have conflicting uses and to promote interoperability, their al
locations are often coordinated by a central record keeper. For IETF protocols,
that role is filled by the Internet Assigned Numbers Authority (IANA).</t>
<t>To make assignments in a given registry prudently, guidance des
cribing the conditions under which new values should be assigned, as well as whe
n and how modifications to existing values can be made, is needed. This document
defines a framework for the documentation of these guidelines by specification
authors, in order to assure that the provided guidance for the IANA Consideratio
ns is clear and addresses the various issues that are likely in the operation of
a registry.</t>
<t>This is the third edition of this document; it obsoletes RFC 52
26.</t>
</abstract>
</front>
<seriesInfo name="BCP" value="26"/>
<seriesInfo name="RFC" value="8126"/>
<seriesInfo name="DOI" value="10.17487/RFC8126"/>
</reference>
<reference anchor="RFC9364" target="https://www.rfc-editor.org/info/rfc9
364">
<front>
<title>DNS Security Extensions (DNSSEC)</title>
<author fullname="P. Hoffman" initials="P." surname="Hoffman"/>
<date month="February" year="2023"/>
<abstract>
<t>This document describes the DNS Security Extensions (commonly c
alled "DNSSEC") that are specified in RFCs 4033, 4034, and 4035, as well as a ha
ndful of others. One purpose is to introduce all of the RFCs in one place so tha
t the reader can understand the many aspects of DNSSEC. This document does not u
pdate any of those RFCs. A second purpose is to state that using DNSSEC for orig
in authentication of DNS data is the best current practice. A third purpose is t
o provide a single reference for other documents that want to refer to DNSSEC.</
t>
</abstract>
</front>
<seriesInfo name="BCP" value="237"/>
<seriesInfo name="RFC" value="9364"/>
<seriesInfo name="DOI" value="10.17487/RFC9364"/>
</reference>
<reference anchor="FAA-14CFR" target="https://www.govinfo.gov/content/pk g/FR-2021-01-15/pdf/2020-28948.pdf"> <reference anchor="FAA-14CFR" target="https://www.govinfo.gov/content/pk g/FR-2021-01-15/pdf/2020-28948.pdf">
<front> <front>
<title>Remote Identification of Unmanned Aircraft</title> <title>Remote Identification of Unmanned Aircraft</title>
<author> <author>
<organization/> <organization>Federal Aviation Administration (FAA)</organization>
</author> </author>
<date year="2021" month="January"/> <date year="2021" month="January"/>
</front> </front>
</reference> </reference>
<reference anchor="ASTM-Remote-ID" target="https://www.icao.int/airnavig ation/IATF/Pages/ASTM-Remote-ID.aspx"> <reference anchor="ASTM-Remote-ID" target="https://www.icao.int/airnavig ation/IATF/Pages/ASTM-Remote-ID.aspx">
<front> <front>
<title>ICAO Remote ID Number Registration</title> <title>Remote ID Number Registration</title>
<author> <author>
<organization/> <organization>International Civil Aviation Organization (ICAO)</or
</author> ganization>
</author>
<date year="2023" month="December"/> <date year="2023" month="December"/>
</front> </front>
</reference> </reference>
</references> </references>
</references> </references>
<section anchor="auth-state-diagrams" numbered="true" toc="default"> <section anchor="auth-state-diagrams" numbered="true" toc="default">
<name>Authentication States</name> <name>Authentication States</name>
<t>ASTM Authentication has only three states: None, Invalid, and Valid. Th <t>ASTM Authentication has only three states: None, Invalid, and Valid. Th
is is because, under ASTM, the authentication is done by an external service hos is is because, under ASTM, the authentication is done by an external service hos
ted somewhere on the Internet so it is assumed an authoritative response will al ted somewhere on the Internet so it is assumed an authoritative response will al
ways be returned. This classification becomes more complex in DRIP with the supp ways be returned. This classification becomes more complex in DRIP with the supp
ort of "offline" scenarios where a Observer does not have Internet connectivity. ort of "offline" scenarios where an Observer does not have Internet connectivity
With the use of asymmetric cryptography this means that the public key (PK) mus . With the use of asymmetric cryptography, this means that the public key (PK) m
t somehow be obtained. <xref target="drip-registries" format="default"/> gets mo ust somehow be obtained. <xref target="I-D.ietf-drip-registries" format="default
re into detail how these keys are stored on DNS and one use of DRIP Authenticati "/> provides more detail on how these keys are stored on the DNS and how DRIP Au
on messages is to send PK's over Broadcast RID.</t> thentication Messages can be used to send PK's over Broadcast RID.</t>
<t>There are a few keys of interest: the PK of the UA and the PK's of rele <t>There are a few keys of interest: the PK of the UA and the PKs of relev
vant DIMEs. This document describes how to send the PK of the UA over the Broadc ant DIMEs. This document describes how to send the PK of the UA over the Broadca
ast RID messages. The key of DIMEs are sent over Broadcast RID using the same me st RID messages. The keys of DIMEs are sent over Broadcast RID using the same me
chanisms (see <xref target="drip-link" format="default"/> and <xref target="drip chanisms (see Sections <xref target="drip-link" format="counter"/> and <xref tar
-recommendations" format="default"/>) but MAY be sent at a far lower rate due to get="drip-recommendations" format="counter"/>) but <bcp14>MAY</bcp14> be sent at
potential operational constraints (such as saturation of limited bandwidth). As a far lower rate due to potential operational constraints (such as saturation o
such, there are scenarios where part of the key-chain may be unavailable at the f limited bandwidth). As such, there are scenarios where part of the key-chain m
moment a full Authentication Message is received and processed.</t> ay be unavailable at the moment a full Authentication Message is received and pr
<t>The intent of this informative appendix is to give a recommended way to ocessed.</t>
classify these various states and convey it to the user through colors and stat <t>The intent of this informative appendix is to recommend a way to classi
e names/text. These states can apply to either a single authentication message, fy these various states and convey it to the user through colors and state names
a DET (and its associated public key), and/or a sender.</t> /text. These states can apply to either a single Authentication Message, a DET (
<t>The table below lays out the recommended colors to associate with state and its associated public key), and/or a sender.</t>
and a brief description of each.</t>
<t>The table below briefly describes each state and recommends an associat
ed color.</t>
<table align="center"> <table align="center">
<name>Authentication State Names, Colors &amp; Descriptions</name> <name>Authentication State Names, Colors, and Descriptions</name>
<thead> <thead>
<tr> <tr>
<th align="left">State</th> <th align="left">State</th>
<th align="left">Color</th> <th align="left">Color</th>
<th align="left">Details</th> <th align="left">Details</th>
</tr> </tr>
</thead> </thead>
<tbody> <tbody>
<tr> <tr>
<td align="left">None</td> <td align="left">None</td>
<td align="left">Black</td> <td align="left">Black</td>
<td align="left">No Authentication being received (as yet)</td> <td align="left">No Authentication has been or is being received (as yet)</td>
</tr> </tr>
<tr> <tr>
<td align="left">Partial</td> <td align="left">Partial</td>
<td align="left">Gray</td> <td align="left">Gray</td>
<td align="left">Authentication being received but missing pages</td > <td align="left">Authentication being received but missing pages</td >
</tr> </tr>
<tr> <tr>
<td align="left">Unsupported</td> <td align="left">Unsupported</td>
<td align="left">Brown</td> <td align="left">Brown</td>
<td align="left">Authentication Type/SAM Type of received message no t supported</td> <td align="left">Authentication Type / SAM Type of received message not supported</td>
</tr> </tr>
<tr> <tr>
<td align="left">Unverifiable</td> <td align="left">Unverifiable</td>
<td align="left">Yellow</td> <td align="left">Yellow</td>
<td align="left">Data needed for signature verification is missing</ td> <td align="left">Data needed for signature verification is missing</ td>
</tr> </tr>
<tr> <tr>
<td align="left">Verified</td> <td align="left">Verified</td>
<td align="left">Green</td> <td align="left">Green</td>
<td align="left">Valid signature verification and content validation </td> <td align="left">Valid signature verification and content validation </td>
</tr> </tr>
<tr> <tr>
<td align="left">Trusted</td> <td align="left">Trusted</td>
<td align="left">Blue</td> <td align="left">Blue</td>
<td align="left">evidence of Verified and DIME is marked as only reg istering DETs for trusted entities</td> <td align="left">Evidence of Verified and DIME is marked as only reg istering DETs for trusted entities</td>
</tr> </tr>
<tr> <tr>
<td align="left">Unverified</td> <td align="left">Unverified</td>
<td align="left">Red</td> <td align="left">Red</td>
<td align="left">Invalid signature verification or content validatio n</td> <td align="left">Invalid signature verification or content validatio n</td>
</tr> </tr>
<tr> <tr>
<td align="left">Questionable</td> <td align="left">Questionable</td>
<td align="left">Orange</td> <td align="left">Orange</td>
<td align="left">evidence of both Verified &amp; Unverified for the same claimed sender</td> <td align="left">Evidence of both"Verified and Unverified for the sa me claimed sender</td>
</tr> </tr>
<tr> <tr>
<td align="left">Conflicting</td> <td align="left">Conflicting</td>
<td align="left">Purple</td> <td align="left">Purple</td>
<td align="left">evidence of both Trusted &amp; Unverified for the s ame claimed sender</td> <td align="left">Evidence of both Trusted and Unverified for the sam e claimed sender</td>
</tr> </tr>
</tbody> </tbody>
</table> </table>
<section anchor="black" numbered="true" toc="default"> <section anchor="black" numbered="true" toc="default">
<name>None: Black</name> <name>None: Black</name>
<t>The default state where no authentication information has yet to be r <!-- [rfced] Regarding the description of "black" in A.1:
eceived.</t>
Authors:
NEW:
A.1. None: Black
The default state where as yet authentication information neither has been
nor is currently being received.
We updated this as follows; please let us know if this is incorrect.
A.1. None: Black
The default state where authentication information has not yet been received
and is not currently being received.
-->
<t>The default state where authentication information has not yet been r
eceived and is not currently being received.</t>
</section> </section>
<section anchor="gray" numbered="true" toc="default"> <section anchor="gray" numbered="true" toc="default">
<name>Partial: Gray</name> <name>Partial: Gray</name>
<t>A pending state where authentication pages are being received but a f ull authentication message has yet to be compiled.</t> <t>A pending state where authentication pages are being received, but a full Authentication Message has yet to be compiled.</t>
</section> </section>
<section anchor="brown" numbered="true" toc="default"> <section anchor="brown" numbered="true" toc="default">
<name>Unsupported: Brown</name> <name>Unsupported: Brown</name>
<t>A state wherein authentication data is being or has been received, bu t cannot be used, as the Authentication Type or SAM Type is not supported by the Observer.</t> <t>A state wherein authentication data is being or has been received but cannot be used, as the Authentication Type or SAM Type is not supported by the Observer.</t>
</section> </section>
<section anchor="yellow" numbered="true" toc="default"> <section anchor="yellow" numbered="true" toc="default">
<name>Unverifiable: Yellow</name> <name>Unverifiable: Yellow</name>
<t>A pending state where a full authentication message has been received but other information, such as public keys to verify signatures, is missing.</t > <t>A pending state where a full Authentication Message has been received but other information, such as public keys to verify signatures, is missing.</t >
</section> </section>
<section anchor="green" numbered="true" toc="default"> <section anchor="green" numbered="true" toc="default">
<name>Verified: Green</name> <name>Verified: Green</name>
<t>A state where all authentication messages that have been received, up to that point from that claimed sender, pass signature verification and the req uirement of <xref target="trust-assessment" format="default"/> has been met.</t> <t>A state where all Authentication Messages that have been received fro m that claimed sender up to that point pass signature verification and the requi rement of <xref target="trust-assessment" format="default"/> has been met.</t>
</section> </section>
<section anchor="blue" numbered="true" toc="default"> <section anchor="blue" numbered="true" toc="default">
<name>Trusted: Blue</name> <name>Trusted: Blue</name>
<t>A state where all authentication messages that have been received, up to that point, from that claimed sender, have passed signature verification, th e requirement of <xref target="trust-assessment" format="default"/> has been met , and the public key of the sending UA is marked as trusted.</t> <t>A state where all Authentication Messages that have been received fro m that claimed sender up to that point have passed signature verification, the r equirement of <xref target="trust-assessment" format="default"/> has been met, a nd the public key of the sending UA has been marked as trusted.</t>
<t>The sending UA key will have been marked as trusted if the relevant D IMEs only register DETs (of subordinate DIMEs, UAS operators, and UA) that have been vetted as per their published registration policies, and those DIMEs have b een marked, by the owner (individual or organizational) of the Observer, as per that owner's policy, as trusted to register DETs only for trusted parties.</t> <t>The sending UA key will have been marked as trusted if the relevant D IMEs only register DETs (of subordinate DIMEs, UAS operators, and UA) that have been vetted as per their published registration policies, and those DIMEs have b een marked, by the owner (individual or organizational) of the Observer, as per that owner's policy, as trusted to register DETs only for trusted parties.</t>
</section> </section>
<section anchor="orange" numbered="true" toc="default"> <section anchor="orange" numbered="true" toc="default">
<name>Questionable: Orange</name> <name>Questionable: Orange</name>
<t>A state where there is a mix of authentication messages received that <t>A state where there is a mix of Authentication Messages received that
are Verified (<xref target="green" format="default"/>) and Unverified (<xref ta are Verified (<xref target="green" format="default"/>) and Unverified (<xref ta
rget="red" format="default"/>).</t> rget="red" format="default"/>).</t>
<t>Transition to this state is from Verified if a subsequent message fai <t>State transitions from Verified to Questionable if a subsequent messa
ls verification so would have otherwise been marked Unverified, or from Unverifi ge fails verification, so it would have otherwise been marked Unverified. State
ed if a subsequent message passes verification or validation so would otherwise transitions from Unverified to Questionable if a subsequent message passes veri
have been marked Verified, or from either of those state upon mixed results on t fication or validation, so it would otherwise have been marked Verified. It may
he requirement of <xref target="trust-assessment" format="default"/>.</t> transition from either of those states upon mixed results on the requirement of
<xref target="trust-assessment" format="default"/>.</t>
</section> </section>
<section anchor="red" numbered="true" toc="default"> <section anchor="red" numbered="true" toc="default">
<name>Unverified: Red</name> <name>Unverified: Red</name>
<t>A state where all authentication messages that have been received, up to that point, from that claimed sender, failed signature verification or the r equirement of <xref target="trust-assessment" format="default"/>.</t> <t>A state where all Authentication Messages that have been received fro m that claimed sender up to that point failed signature verification or the requ irement of <xref target="trust-assessment" format="default"/>.</t>
</section> </section>
<section anchor="purple" numbered="true" toc="default"> <section anchor="purple" numbered="true" toc="default">
<name>Conflicting: Purple</name> <name>Conflicting: Purple</name>
<t>A state where there is a mix of authentication messages received that <t>A state where there is a mix of Authentication Messages received that
are Trusted (<xref target="blue" format="default"/>) and Unverified (<xref targ are Trusted (<xref target="blue" format="default"/>) and Unverified (<xref targ
et="red" format="default"/>) and the public key of the aircraft is marked as tru et="red" format="default"/>) and the public key of the aircraft is marked as tru
sted.</t> sted.</t>
<t>Transition to this state is from Trusted if a subsequent message fail <t>State transitions from Trusted to Conflicting if a subsequent message
s verification so would have otherwise been marked Unverified, or from Unverifie fails verification, so it would have otherwise been marked Unverified. State t
d if a subsequent message passes verification or validation and policy checks so ransitions from Unverified to Conflicting if a subsequent message passes verific
would otherwise have been marked Trusted, or from either of those state upon mi ation or validation and policy checks, so it would otherwise have been marked Tr
xed results on the requirement of <xref target="trust-assessment" format="defaul usted. It may transition from either of those states upon mixed results on the r
t"/>.</t> equirement of <xref target="trust-assessment" format="default"/>.</t>
</section> </section>
</section> </section>
<section anchor="operational-proof" numbered="true" toc="default"> <section anchor="operational-proof" numbered="true" toc="default">
<name>Operational Recommendation Analysis</name> <name>Operational Recommendation Analysis</name>
<t>The recommendations found in <xref target="operational-recommendations" <t>The recommendations in <xref target="operational-recommendations" forma
format="default"/> may seem heavy handed and specific. This informative appendi t="default"/> may seem heavy-handed and specific. This informative appendix lays
x lays out the math and assumptions made to come to the recommendations listed t out the math and assumptions made that resulted in those recommendations and pr
here as well as an example.</t> ovides an example.</t>
<t>In many jurisdictions, the required ASTM Messages to be transmitted eve
ry second are: Basic ID (0x1), Location (0x2), and System (0x4). Typical impleme <t>In many jurisdictions, the required ASTM Messages to be transmitted eve
ntations will most likely send at a higher rate (2x sets per cycle) resulting in ry second are: Basic ID (0x0), Location/Vector (0x1), and System (0x4). Typical
6 frames sent per cycle. Transmitting this set of message more than once a seco implementations will most likely send at a higher rate (2x sets per cycle) resul
nd is not discouraged but awareness is needed to avoid congesting the RF spectru ting in 6 frames sent per cycle. Transmitting this set of messages more than onc
m, causing further issues.</t> e a second is not discouraged, but awareness is needed to avoid congesting the R
<ul empty="true" spacing="normal"> F spectrum, causing further issues.</t>
<li>Informational Note: In Europe, the Operator ID Message (0x5) is also <t>Informational Note: In Europe, the Operator ID Message (0x5) is also
required. In Japan, two Basic ID (0x0), Location (0x1), and Authentication (0x2 required. In Japan, two Basic ID (0x0), Location/Vector (0x1), and Authenticatio
) are required. Self ID (0x3) is optional but can carry Emergency Status informa n (0x2) are required. Self ID (0x3) is optional but can carry Emergency Status i
tion.</li> nformation.</t>
</ul>
<section anchor="page-counts-vs-frame-counts" numbered="true" toc="default "> <section anchor="page-counts-vs-frame-counts" numbered="true" toc="default ">
<name>Page Counts vs Frame Counts</name> <name>Page Counts vs Frame Counts</name>
<t>There are two formulas to determine the number of Authentication Page <t>There are two formulas to determine the number of Authentication Page
s required, one for Wrapper:</t> s required. The following formula is for Wrapper:</t>
<sourcecode name="" type="" markers="true"><![CDATA[ <sourcecode name="" type="" markers="true"><![CDATA[
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
]]></sourcecode> ]]></sourcecode>
<t>and one for Manifest:</t>
<sourcecode name="" type="" markers="true"><![CDATA[
<t>The following formula is for Manifest:</t>
<sourcecode name="" type="" markers="true"><![CDATA[
manifest_struct_size = 89 + (8 * (num_astm_hashes + 3)) manifest_struct_size = 89 + (8 * (num_astm_hashes + 3))
manifest_page_count = ceiling((manifest_struct_size - 17) / 23) + 1 manifest_page_count = ceiling((manifest_struct_size - 17) / 23) + 1
]]></sourcecode> ]]></sourcecode>
<t>A similar formula can be applied to Link as they are of fixed size:</
t>
<sourcecode name="" type="" markers="true"><![CDATA[
<t>A similar formula can be applied to Links, as they are of fixed size:
</t>
<sourcecode name="" type="" markers="true"><![CDATA[
link_page_count = ceiling((137 - 17) / 23) + 1 = 7 link_page_count = ceiling((137 - 17) / 23) + 1 = 7
]]></sourcecode> ]]></sourcecode>
<t>Comparing Wrapper and Manifest Authentication Message page counts aga
inst total frame counts we have the following:</t> <t>Comparing Wrapper and Manifest Authentication Message page counts aga
inst total frame counts, we have the following:</t>
<table anchor="tbl-page-counts" align="center"> <table anchor="tbl-page-counts" align="center">
<name>Page &amp; Frame Counts</name> <name>Page and Frame Counts</name>
<thead> <thead>
<tr> <tr>
<th align="left">ASTM Messages</th> <th align="left">ASTM Messages</th>
<th align="left">Wrapper (w/FEC)</th> <th align="left">Wrapper (w/FEC)</th>
<th align="left">Manifest (w/FEC)</th> <th align="left">Manifest (w/FEC)</th>
<th align="left">ASTM Messages + Wrapper (w/FEC)</th> <th align="left">ASTM Messages + Wrapper (w/FEC)</th>
<th align="left">ASTM Messages + Manifest (w/FEC)</th> <th align="left">ASTM Messages + Manifest (w/FEC)</th>
</tr> </tr>
</thead> </thead>
<tbody> <tbody>
skipping to change at line 1404 skipping to change at line 1435
<td align="left">N/A</td> <td align="left">N/A</td>
<td align="left">20 (22)</td> <td align="left">20 (22)</td>
</tr> </tr>
</tbody> </tbody>
</table> </table>
<t>Link shares the same page counts as Manifest with 5 ASTM Messages.</t > <t>Link shares the same page counts as Manifest with 5 ASTM Messages.</t >
<section anchor="special-cases" numbered="true" toc="default"> <section anchor="special-cases" numbered="true" toc="default">
<name>Special Cases</name> <name>Special Cases</name>
<section anchor="zero-astm-messages" numbered="true" toc="default"> <section anchor="zero-astm-messages" numbered="true" toc="default">
<name>Zero ASTM Messages</name> <name>Zero ASTM Messages</name>
<t>Zero ASTM Messages in <xref target="tbl-page-counts" format="defa ult"/> is where Extended Wrapper (<xref target="extended-wrapper" format="defaul t"/>) without FEC is used in Message Packs. With a max of 9 "message slots" in a Message Pack an Extended Wrapper fills 5 slots, thus can authenticate up to 4 A STM Messages co-located in the same Message Pack.</t> <t>Zero ASTM Messages (see <xref target="tbl-page-counts" format="de fault"/>) is where Extended Wrapper (<xref target="extended-wrapper" format="def ault"/>) without FEC is used in Message Packs. With a maximum of nine "message s lots" in a Message Pack, an Extended Wrapper fills five slots; thus it can authe nticate up to four ASTM Messages co-located in the same Message Pack.</t>
</section> </section>
<section anchor="eleven-astm-messages" numbered="true" toc="default"> <section anchor="eleven-astm-messages" numbered="true" toc="default">
<name>Eleven ASTM Messages</name> <name>Eleven ASTM Messages</name>
<t>Eleven ASTM Messages in <xref target="tbl-page-counts" format="de <t>Eleven ASTM Messages (see <xref target="tbl-page-counts" format="
fault"/> is where a Manifest with FEC invokes the situation mentioned in <xref t default"/>) is where a Manifest with FEC invokes the situation mentioned in <xre
arget="fec-limitations" format="default"/>.</t> f target="fec-limitations" format="default"/>.</t>
<t>Eleven is the max number of ASTM Messages Hashes that can be supp <t>Eleven is the maximum number of ASTM Message Hashes that can be s
orted resulting in 14 total hashes. This completely fills the <tt>evidence</tt> upported resulting in 14 total hashes. This completely fills the <tt>Evidence</t
section of the structure making its total size 200 octets. This fits on exactly t> field of the <tt>UA-Signed Evidence
9 Authentication Pages (<tt>(201 - 17) / 23 == 8</tt>) so when the ADL is added Structure</tt> making its total size 200 octets. This fits on exactly 9 Authenti
it is placed on the next page (Page 10). Per rule 1 in <xref target="enc-single- cation Pages (<tt>(201 - 17) / 23 == 8</tt>), so when the ADL is added, it is pl
page" format="default"/> this means that all of Page 10 is null padded (expect t aced on the next page (Page 10). Per rule 1 in <xref target="enc-single-page" fo
he ADL octet) and FEC data fills Page 11, resulting in a plus two page count whe rmat="default"/>, this means that all of Page 10 is null padded (expect the ADL
n FEC is applied.</t> octet) and FEC data fills Page 11, resulting in a plus-two page count when FEC i
<t>This drives the recommendation is <xref target="drip-manifest" fo s applied.</t>
rmat="default"/> to only use up to 10 ASTM Message Hashes and not 11.</t> <t>This drives the recommendation is <xref target="drip-manifest" fo
rmat="default"/> to only use up to 10 ASTM Message Hashes, not 11.</t>
</section> </section>
</section> </section>
</section> </section>
<section anchor="full-authentication-example" numbered="true" toc="default "> <section anchor="full-authentication-example" numbered="true" toc="default ">
<name>Full Authentication Example</name> <name>Full Authentication Example</name>
<t>This example is focused on showing that 100% of ASTM Messages can be <t>This example is focused on showing that 100% of ASTM Messages can be
authenticated over Legacy Transports with up to 125% overhead in Authentication authenticated over Legacy Transports with up to 125% overhead in Authentication
Pages. Extended Transports is not shown as Authentication with DRIP in that case Pages.
is covered using Extended Wrapper (<xref target="extended-wrapper" format="defa Extended Transports are not shown in this example, because, for those,
ult"/>). Two ASTM Message Packs are sent in a given cycle: one containing up to Authentication with DRIP is achieved using Extended Wrapper
4 ASTM Messages and an Extended Wrapper (authenticating the pack) and one contai (<xref target="extended-wrapper" format="default"/>).
ning a Link message with a Broadcast Endorsement and up to two other ASTM Messag Two ASTM Message Packs are sent in a given cycle: one containing up to four ASTM
es.</t> Messages and an Extended Wrapper (authenticating the pack), and one containing
a Link message with a Broadcast Endorsement and up to two other ASTM Messages.</
t>
<t>This example transmit scheme covers and meets every known regulatory case enabling manufacturers to use the same firmware worldwide.</t> <t>This example transmit scheme covers and meets every known regulatory case enabling manufacturers to use the same firmware worldwide.</t>
<figure anchor="max-schedule-fig"> <figure anchor="max-schedule-fig">
<name>Full Authenticated Legacy Transport Transmit Schedule Example</n ame> <name>Example of a Fully Authenticated Legacy Transport Transmit Sched ule</name>
<artwork align="center" name="" type="" alt=""><![CDATA[ <artwork align="center" name="" type="" alt=""><![CDATA[
+------------------------------------------------------+ +------------------------------------------------------+
| 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] |
+-------------------+---------------+---------+--------+ +-------------------+---------------+---------+--------+
| {A|B|C|D},V,S,I,O | {A|B|C|D},V,S | M[0,8] | L/W[1] | | {A|B|C|D},V,S,I,O | {A|B|C|D},V,S | M[0,8] | L/W[1] |
+-------------------+---------------+---------+--------+ +-------------------+---------------+---------+--------+
| {A|B|C|D},V,S,I,O | {A|B|C|D},V,S | M[0,8] | L/W[2] | | {A|B|C|D},V,S,I,O | {A|B|C|D},V,S | M[0,8] | L/W[2] |
skipping to change at line 1461 skipping to change at line 1497
L[y,z] = DRIP Link Authentication Message (0x2) L[y,z] = DRIP Link Authentication Message (0x2)
W[y,z] = DRIP Wrapper Authentication Message (0x2) W[y,z] = DRIP Wrapper Authentication Message (0x2)
M[y,z] = DRIP Manifest Authentication Message (0x2) M[y,z] = DRIP Manifest Authentication Message (0x2)
y = Start Page y = Start Page
z = End Page z = End Page
# = Empty Frame Slot # = Empty Frame Slot
* = Message in DRIP Manifest Authentication Message * = Message in DRIP Manifest Authentication Message
]]></artwork> ]]></artwork>
</figure> </figure>
<t>Every common required message (Basic ID, Location and System) is sent <t>Every common required message (Basic ID, Location/Vector, and System)
twice plus Operator ID and Self ID in a single second. The Manifest is over all is sent twice along with Operator ID and Self ID in a single second. The Manife
messages (8) in slots <tt>00 - 04</tt> and <tt>05 - 07</tt>.</t> st is over all messages (8) in slots <tt>00 - 04</tt> and <tt>05 - 07</tt>.</t>
<t>In two seconds either a Link or Wrapper are sent. The content and ord <t>In two seconds, either a Link or Wrapper is sent. The content and ord
er of Links and Wrappers runs as follows:</t> er of Links and Wrappers runs as follows:</t>
<artwork name="" type="" align="left" alt=""><![CDATA[ <artwork name="" type="" align="left" alt=""><![CDATA[
Link: HDA on UA Link: HDA on UA
Link: RAA on HDA Link: RAA on HDA
Link: HDA on UA Link: HDA on UA
Link: Apex on RAA Link: Apex on RAA
Link: HDA on UA Link: HDA on UA
Link: RAA on HDA Link: RAA on HDA
Link: HDA on UA Link: HDA on UA
Wrapper: Location (0x1), System (0x4) Wrapper: Location/Vector (0x1), System (0x4)
Link: HDA on UA Link: HDA on UA
Link: RAA on HDA Link: RAA on HDA
Link: HDA on UA Link: HDA on UA
Link: Apex on RAA Link: Apex on RAA
Link: HDA on UA Link: HDA on UA
Link: RAA on HDA Link: RAA on HDA
Link: HDA on UA Link: HDA on UA
Wrapper: Location (0x1), System (0x4) Wrapper: Location/Vector (0x1), System (0x4)
Link: IANA on UAS RID Apex Link: IANA on UAS RID Apex
]]></artwork> ]]></artwork>
<t>With perfect receipt of all messages, in 8 seconds all messages (up t <t>After perfect receipt of all messages for a period of 8 seconds,
o that point then all in future) are authenticated using the Manifest. Within 13 all messages sent during that period have been authenticated using the Manifes
6 seconds the entire Broadcast Endorsement chain is received and can be validate t
d; interspersed with 4 messages directly signed over via Wrapper.</t> (except for the Authentication Messages themselves).
Within 136 seconds, the entire Broadcast Endorsement chain
is received and can be validated. Interspersed in this schedule
are 4 messages sent not only in their basic <xref target="F3411"/> form, but a
lso
in DRIP Wrapper messages, together with their attached signatures,
to defend against the possibility of attack against the detached signatures
provided by the Manifest messages.</t>
<section anchor="raw-example" numbered="true" toc="default"> <section anchor="raw-example" numbered="true" toc="default">
<name>Raw Example</name> <name>Raw Example</name>
<t>Assuming the following DET and HI:</t> <t>Assuming the following DET and HI:</t>
<artwork name="" type="" align="left" alt=""><![CDATA[ <artwork name="" type="" align="left" alt=""><![CDATA[
2001:3f:fe00:105:a29b:3ff4:2226:c04e 2001:3f:fe00:105:a29b:3ff4:2226:c04e
b5fef530d450dedb59ebafa18b00d7f5ed0ac08a81975034297bea2b00041813 b5fef530d450dedb59ebafa18b00d7f5ed0ac08a81975034297bea2b00041813
]]></artwork> ]]></artwork>
<t>The following ASTM Messages to be sent in a single second:</t> <t>The following ASTM Messages are to be sent in a single second:</t>
<artwork name="" type="" align="left" alt=""><![CDATA[ <artwork name="" type="" align="left" alt=""><![CDATA[
0240012001003ffe000105a29b3ff42226c04e000000000000 0240012001003ffe000105a29b3ff42226c04e000000000000
12000000000000000000000000000000000000000060220000 12000000000000000000000000000000000000000060220000
32004578616d706c652053656c662049440000000000000000 32004578616d706c652053656c662049440000000000000000
420000000000000000000100000000000000000010ea510900 420000000000000000000100000000000000000010ea510900
52004578616d706c65204f70657261746f7220494400000000 52004578616d706c65204f70657261746f7220494400000000
0240012001003ffe000105a29b3ff42226c04e000000000000 0240012001003ffe000105a29b3ff42226c04e000000000000
12000000000000000000000000000000000000000060220000 12000000000000000000000000000000000000000060220000
420000000000000000000100000000000000000010ea510900 420000000000000000000100000000000000000010ea510900
]]></artwork> ]]></artwork>
<t>This is Link with FEC that would be spread out over 8 seconds:</t> <t>This is a Link with FEC that would be spread out over 8 seconds:</t >
<artwork name="" type="" align="left" alt=""><![CDATA[ <artwork name="" type="" align="left" alt=""><![CDATA[
2250078910ea510904314b8564b17e66662001003ffe000105 2250078910ea510904314b8564b17e66662001003ffe000105
2251a29b3ff42226c04eb5fef530d450dedb59ebafa18b00d7 2251a29b3ff42226c04eb5fef530d450dedb59ebafa18b00d7
2252f5ed0ac08a81975034297bea2b000418132001003ffe00 2252f5ed0ac08a81975034297bea2b000418132001003ffe00
22530105b82bf1c99d87273103fc83f6ecd9b91842f205c222 22530105b82bf1c99d87273103fc83f6ecd9b91842f205c222
2254dd71d8e165ad18ca91daf9299a73eec850c756a7e9be46 2254dd71d8e165ad18ca91daf9299a73eec850c756a7e9be46
2255f51dddfa0f09db7bfdde14eec07c7a6dd1061c1d5ace94 2255f51dddfa0f09db7bfdde14eec07c7a6dd1061c1d5ace94
2256d9ad97940d280000000000000000000000000000000000 2256d9ad97940d280000000000000000000000000000000000
2257a03b0f7a6feb0d198167045058cfc49f73129917024d22 2257a03b0f7a6feb0d198167045058cfc49f73129917024d22
]]></artwork> ]]></artwork>
skipping to change at line 1538 skipping to change at line 1582
22538884e3e28a24fd5529bc2bd4862734ed012ca2e5f2b8a3 22538884e3e28a24fd5529bc2bd4862734ed012ca2e5f2b8a3
2254e61547b81704766ba3eeb62001003ffe000105a29b3ff4 2254e61547b81704766ba3eeb62001003ffe000105a29b3ff4
22552226c04efb729846e7d110903797066fd96f49a77c5a48 22552226c04efb729846e7d110903797066fd96f49a77c5a48
2256c4c3b330be05bc4a958e9641718aaa31aeabad368386a2 2256c4c3b330be05bc4a958e9641718aaa31aeabad368386a2
22579ed2dce2769120da83edbcdc0858dd1e357755e7860317 22579ed2dce2769120da83edbcdc0858dd1e357755e7860317
2258e7c06a5918ea62a937391cbfe0983539de1b2e688b7c83 2258e7c06a5918ea62a937391cbfe0983539de1b2e688b7c83
]]></artwork> ]]></artwork>
</section> </section>
</section> </section>
</section> </section>
<section anchor="acknowledgments" numbered="false" toc="default">
<name>Acknowledgments</name>
<t>The authors acknowledge the following individuals:</t>
<ul spacing="normal">
<li><t><contact fullname="Ryan Quigley"/>, <contact fullname="James
Mussi"/>, and <contact fullname="Joseph Stanton"/> of AX Enterprize,
LLC for early prototyping to find holes in earlier drafts of this
specification.</t></li>
<li><t><contact fullname="Carsten Bormann"/> for the simple approach of
using bit-column-wise
parity for erasure (dropped frame) FEC.</t></li>
<li><t><contact fullname="Soren Friis"/> for pointing out that Wi-Fi imp
lementations would not always give access to the MAC Address, as was originally
used in calculation of the hashes for DRIP Manifest. Also, for confirming that M
essage Packs (0xF) can only carry up to 9 ASTM frames worth of data (9 Authentic
ation pages)</t></li>
<li><t><contact fullname="Gabriel Cox"/> (chair of the working group tha
t produced <xref target="F3411" format="default"/>) for reviewing the specificat
ion for the SAM Type request as the ASTM Designated Expert.</t></li>
<li><t><contact fullname="Mohamed Boucadair"/> (Document Shepherd) for h
is many patches and comments.</t></li>
<li><t><contact fullname="Eric Vyncke"/> (DRIP AD) for his guidance rega
rding the document's path to publication.</t></li></ul>
<t>The authors also thank the following reviewers:</t>
<ul spacing="normal">
<li><t><contact fullname="Rick Salz (secdir)"/></t></li>
<li><t><contact fullname="Matt Joras (genart)"/></t></li>
<li><t><contact fullname="Di Ma (dnsdir)"/></t></li>
<li><t><contact fullname="Gorry Fairhurst (tsvart)"/></t></li>
<li><t><contact fullname="Carlos Bernardos (intdir)"/></t></li>
<li><t><contact fullname="Behcet Sarikaya (iotdir)"/></t></li>
<li><t><contact fullname="Martin Duke (IESG)"/></t></li>
<li><t><contact fullname="Roman Danyliw (IESG)"/></t></li>
<li><t><contact fullname="Murray Kucherawy (IESG)"/></t></li>
<li><t><contact fullname="Erik Kline (IESG)"/></t></li>
<li><t><contact fullname="Warren Kumari (IESG)"/></t></li>
<li><t><contact fullname="Paul Wouters (IESG)"/></t></li>
</ul>
</section>
</back> </back>
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<!-- [rfced] We have the following questions regarding the use of elements used
for emphasis.
a) Is the intent to use <tt> to denote field names? If so, it does not appear t
o have been
applied consistently. For example, in the explanatory text following figures, <
tt> is
not used for field names.
<t>Authentication Data / Signature: (0 to 255 octets)</t>
Please review and update as needed.
c) It is unclear why the following appear in <tt>. For example, why do "361"
and "255" appear within <tt>?
<tt>361 - Authentication Data / Signature Length</tt>
<tt>255</tt>
<tt>00 - 04</tt> and <tt>05 - 07</tt> (slots)
<tt>number of padding octets + number of parity octets</tt>
<tt>2019-01-01 00:00:00 UTC</tt>
<tt>wrapperLength</tt>
<tt>manifestLength</tt>
authors: no change
d) Please review the use of <tt> for the following, as <tt> seems to be applied
inconsistently. Please review and update as needed.
<tt>Valid Not Before (VNB)</tt>
<tt>Valid Not After (VNA)</tt>
<tt>VNB</tt>
<tt>VNA</tt>
authors: no change
e) We also note a few instances of <strong> and <em>. Are these necessary?
If so, should they be made consistent? Note that we see a few instances of "N
frames" that are not enclosed within either of these elements.
<strong>16 frames</strong>
<strong>36 frames</strong>
<strong>25 frames</strong>
<em>20 frames</em>
<em>9 frames</em>
authors: no change
-->
<!-- [rfced] Please review the "Inclusive Language" portion of the online
Style Guide <https://www.rfc-editor.org/styleguide/part2/#inclusive_language>
and let us know if any changes are needed.
For example, please consider whether the following should be updated:
Sanity
--> -->
</rfc> </rfc>
 End of changes. 143 change blocks. 
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