BRSKI with Pledge in Responder Mode (BRSKI-PRM)
draft-ietf-anima-brski-prm-11
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Active".
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|---|---|---|---|
| Authors | Steffen Fries , Thomas Werner , Eliot Lear , Michael Richardson | ||
| Last updated | 2024-02-06 (Latest revision 2023-11-20) | ||
| Replaces | draft-ietf-anima-brski-async-enroll | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
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| Additional resources | Mailing list discussion | ||
| Stream | WG state | In WG Last Call | |
| Document shepherd | Matthias Kovatsch | ||
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| Send notices to | ietf@kovatsch.net |
draft-ietf-anima-brski-prm-11
ANIMA WG S. Fries
Internet-Draft T. Werner
Intended status: Standards Track Siemens
Expires: 23 May 2024 E. Lear
Cisco Systems
M. Richardson
Sandelman Software Works
20 November 2023
BRSKI with Pledge in Responder Mode (BRSKI-PRM)
draft-ietf-anima-brski-prm-11
Abstract
This document defines enhancements to Bootstrapping a Remote Secure
Key Infrastructure (BRSKI, RFC8995) to enable bootstrapping in
domains featuring no or only limited connectivity between a pledge
and the domain registrar. It specifically changes the interaction
model from a pledge-initiated mode, as used in BRSKI, to a pledge-
responding mode, where the pledge is in server role. For this, BRSKI
with Pledge in Responder Mode (BRSKI-PRM) introduces a new component,
the Registrar-Agent, which facilitates the communication between
pledge and registrar during the bootstrapping phase. To establish
the trust relation between pledge and registrar, BRSKI-PRM relies on
object security rather than transport security. The approach defined
here is agnostic to the enrollment protocol that connects the domain
registrar to the domain CA.
About This Document
This note is to be removed before publishing as an RFC.
Status information for this document may be found at
https://datatracker.ietf.org/doc/draft-ietf-anima-brski-prm/.
Source for this draft and an issue tracker can be found at
https://github.com/anima-wg/anima-brski-prm.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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Task Force (IETF). Note that other groups may also distribute
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Scope of Solution . . . . . . . . . . . . . . . . . . . . . . 7
3.1. Supported Environments and Use Case Examples . . . . . . 7
3.1.1. Building Automation . . . . . . . . . . . . . . . . . 8
3.1.2. Infrastructure Isolation Policy . . . . . . . . . . . 8
3.1.3. Less Operational Security in the Target-Domain . . . 8
3.2. Limitations . . . . . . . . . . . . . . . . . . . . . . . 9
4. Requirements Discussion and Mapping to Solution-Elements . . 9
5. Architecture . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 11
5.2. Nomadic connectivity . . . . . . . . . . . . . . . . . . 14
5.3. Registrar-Agent co-located with registrar . . . . . . . . 16
5.4. Agent-Proximity Assertion . . . . . . . . . . . . . . . . 17
5.5. Behavior of Pledge in Pledge-Responder-Mode . . . . . . . 18
5.6. Behavior of Registrar-Agent . . . . . . . . . . . . . . . 19
5.6.1. Discovery of Registrar by Registrar-Agent . . . . . . 22
5.6.2. Discovery of Pledge by Registrar-Agent . . . . . . . 22
5.7. Behavior of Pledge with Combined Functionality . . . . . 23
6. Bootstrapping Data Objects and Corresponding Exchanges . . . 23
6.1. Request Objects Acquisition by Registrar-Agent from
Pledge . . . . . . . . . . . . . . . . . . . . . . . . . 26
6.1.1. Pledge-Voucher-Request (PVR) - Trigger . . . . . . . 28
6.1.2. Pledge-Voucher-Request (PVR) - Response . . . . . . . 30
6.1.3. Pledge-Enrollment-Request (PER) - Trigger . . . . . . 33
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6.1.4. Pledge-Enrollment-Request (PER) - Response . . . . . 33
6.2. Request Object Handling initiated by the Registrar-Agent on
Registrar, MASA and Domain CA . . . . . . . . . . . . . . 37
6.2.1. Connection Establishment (Registrar-Agent to
Registrar) . . . . . . . . . . . . . . . . . . . . . 39
6.2.2. Pledge-Voucher-Request (PVR) Processing by
Registrar . . . . . . . . . . . . . . . . . . . . . . 39
6.2.3. Registrar-Voucher-Request (RVR) Processing (Registrar
to MASA) . . . . . . . . . . . . . . . . . . . . . . 40
6.2.4. Voucher Issuance by MASA . . . . . . . . . . . . . . 44
6.2.5. MASA issued Voucher Processing by Registrar . . . . . 45
6.2.6. Pledge-Enrollment-Request (PER) Processing
(Registrar-Agent to Registrar) . . . . . . . . . . . 48
6.2.7. Request Wrapped-CA-certificate(s) (Registrar-Agent to
Registrar) . . . . . . . . . . . . . . . . . . . . . 49
6.3. Response Objects supplied by the Registrar-Agent to the
Pledge . . . . . . . . . . . . . . . . . . . . . . . . . 51
6.3.1. Pledge: Voucher-Response Processing . . . . . . . . . 52
6.3.2. Pledge: Voucher Status Telemetry . . . . . . . . . . 53
6.3.3. Pledge: Wrapped-CA-Certificate(s) Processing . . . . 55
6.3.4. Pledge: Enrollment-Response Processing . . . . . . . 56
6.3.5. Pledge: Enrollment-Status Telemetry . . . . . . . . . 56
6.3.6. Telemetry Voucher Status and Enroll Status Handling
(Registrar-Agent to Domain Registrar) . . . . . . . . 58
6.4. Request Pledge-Status by Registrar-Agent from Pledge . . 60
6.4.1. Pledge-Status - Request (Registrar-Agent to
Pledge) . . . . . . . . . . . . . . . . . . . . . . . 61
6.4.2. Pledge-Status - Response (Pledge -
Registrar-Agent) . . . . . . . . . . . . . . . . . . 62
7. Artifacts . . . . . . . . . . . . . . . . . . . . . . . . . . 66
7.1. Voucher-Request Artifact . . . . . . . . . . . . . . . . 66
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 66
8.1. BRSKI .well-known Registry . . . . . . . . . . . . . . . 66
8.2. DNS Service Names . . . . . . . . . . . . . . . . . . . . 67
9. Privacy Considerations . . . . . . . . . . . . . . . . . . . 67
10. Security Considerations . . . . . . . . . . . . . . . . . . . 68
10.1. Denial of Service (DoS) Attack on Pledge . . . . . . . . 68
10.2. Misuse of acquired PVR and PER by Registrar-Agent . . . 69
10.3. Misuse of Registrar-Agent Credentials . . . . . . . . . 69
10.4. Misuse of DNS-SD with mDNS to obtain list of pledges . . 70
10.5. YANG Module Security Considerations . . . . . . . . . . 70
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 71
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 71
12.1. Normative References . . . . . . . . . . . . . . . . . . 71
12.2. Informative References . . . . . . . . . . . . . . . . . 72
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 75
A.1. Example Pledge Voucher-Request - PVR (from Pledge to
Registrar-Agent) . . . . . . . . . . . . . . . . . . . . 76
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A.2. Example Parboiled Registrar Voucher-Request - RVR (from
Registrar to MASA) . . . . . . . . . . . . . . . . . . . 77
A.3. Example Voucher-Response (from MASA to Pledge, via
Registrar and Registrar-Agent) . . . . . . . . . . . . . 82
A.4. Example Voucher-Response, MASA issued Voucher with
additional Registrar signature (from MASA to Pledge, via
Registrar and Registrar-Agent) . . . . . . . . . . . . . 83
Appendix B. HTTP-over-TLS operations between Registrar-Agent and
Pledge . . . . . . . . . . . . . . . . . . . . . . . . . 85
Appendix C. History of Changes [RFC Editor: please delete] . . . 86
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 98
1. Introduction
BRSKI as defined in [RFC8995] specifies a solution for secure zero-
touch (automated) bootstrapping of devices (pledges) in a (customer
site) domain. This includes the discovery of the BRSKI registrar in
the customer domain and the exchange of security information
necessary to establish trust between a pledge and the domain.
Security information about the customer domain, specifically the
customer domain certificate, are exchanged and authenticated
utilizing voucher-request and voucher-response artifacts as defined
in [RFC8995]. Vouchers are signed objects from the Manufacturer's
Authorized Signing Authority (MASA). The MASA issues the voucher and
provides it via the domain registrar to the pledge. [RFC8366]
specifies the format of the voucher artifacts.
[I-D.ietf-anima-rfc8366bis] further enhances the format of the
voucher artifacts and also the voucher-request.
For the certificate enrollment of devices, BRSKI relies on EST
[RFC7030] to request and distribute customer domain specific device
certificates. EST in turn relies for the authentication and
authorization of the certification request on the credentials used by
the underlying TLS between the EST client and the EST server.
BRSKI addresses scenarios in which the pledge initiates the
bootstrapping acting as client (referred to as initiator mode by this
document). BRSKI with pledge in responder mode (BRSKI-PRM) defined
in this document allows the pledge to act as server, so that it can
be triggered to generate bootstrapping requests in the customer
domain. For this approach, this document:
* introduces the Registrar-Agent as new component to facilitate the
communication between the pledge and the domain registrar. The
Registrar-Agent may be implemented as an integrated functionality
of a commissioning tool or be co-located with the registrar
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itself. BRSKI-PRM supports the identification of the Registrar-
Agent that was performing the bootstrapping allowing for
accountability of the pledges installation, when the Registrar-
Agent is a component used by an installer and not co-located with
the registrar.
* specifies the interaction (data exchange and data objects) between
a pledge acting as server, the Registrar-Agent acting as client,
and the domain registrar.
* enables the usage of arbitrary transports between the pledge and
the domain registrar via the Registrar-Agent; security is
addressed at the application layer, and both IP-based and non-IP
connectivity can be used between pledge and Registrar-Agent.
* allows the application of Registrar-Agent credentials to establish
TLS connections to the domain registrar; these are different from
the IDevID of the pledge.
The term endpoint used in the context of this document is equivalent
to resource in HTTP [RFC9110] and CoAP [RFC7252]; it is not used to
describe a device. Endpoints are accessible via Well-Known URIs
[RFC8615]. For the interaction with the domain registrar, the
Registrar-Agent will use existing BRSKI [RFC8995] endpoints as well
as additional endpoints defined in this document. To utilize the EST
server endpoints on the domain registrar, the Registrar-Agent will
act as client toward the registrar.
The Registrar-Agent also acts as a client when communicating with a
pledge in responder mode. Here, TLS with server-side, certificate-
based authentication is only optionally supported. If TLS is
optionally used between the Registrar-Agent and the pledge, the
Registrar-Agent needs to identify the pledge based on its product-
serial-number rather than the hostname as this is not set in an
IDevID certificate.
BRSKI-PRM is designed to rely on object security to support also for
alternative transports for which TLS may not be available, e.g.,
Bluetooth or NFC. This is achieved through an additional signature
wrapping of the exchanged data objects involving the Registrar-Agent
for transport.
To utilize EST [RFC7030] for enrollment, the domain registrar must
perform the pre-processing of this wrapping signature before actually
using EST as defined in [RFC7030].
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There may be pledges which can support both modes, initiator and
responder mode. In these cases BRSKI-PRM can be combined with BRSKI
as defined in [RFC8995] or BRSKI-AE [I-D.ietf-anima-brski-ae] to
allow for more bootstrapping flexibility.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
This document relies on the terminology defined in [RFC8995], section
1.2. The following terms are defined additionally:
authenticated self-contained object: Describes an object, which is
cryptographically bound to the end entity (EE) certificate (IDevID
certificate or LDEVID certificate). The binding is assumed to be
provided through a digital signature of the actual object using
the corresponding private key of the certificate.
CA: Certification Authority, issues certificates.
Commissioning tool: Tool to interact with devices to provide
configuration data.
CSR: Certificate Signing Request.
EE: End Entity.
endpoint: term equivalent to resource in HTTP [RFC9110] and CoAP
[RFC7252]. Endpoints are accessible via .well-known URIs.
mTLS: mutual Transport Layer Security.
on-site: Describes a component or service or functionality available
in the customer domain.
off-site: Describes a component or service or functionality not
available on-site. It may be at a central site or an internet
resident "cloud" service. The on-site to off-site connection may
also be temporary and, e.g., only available at times when workers
are present on a construction side, for instance.
PER: Pledge Enrollment-Request is a signature wrapped CSR, signed by
the pledge that requests enrollment to a domain.
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POP: Proof-of-Possession (of a private key), as defined in
[RFC5272].
POI: Proof-of-Identity, as defined in [RFC5272].
PVR: Pledge Voucher-Request is a request for a voucher sent to the
domain registrar. The PVR is signed by the Pledge.
RA: Registration Authority, an optional system component to which a
CA delegates certificate management functions such as
authorization checks. In BRSKI-PRM this is a functionality of the
domain registrar, as in BRSKI [RFC8995].
RER: Registrar Enrollment-Request is the CSR of a PER sent to the CA
by the domain registrar (RA).
RVR: Registrar Voucher-Request is a request for a voucher signed by
the domain registrar to the MASA. It may contain the PVR received
from the pledge.
This document includes many examples that would contain many long
sequences of base64 encoded objects with no content directly
comprehensible to a human reader. In order to keep those examples
short, they use the token "base64encodedvalue==" as a placeholder for
base64 data. The full base64 data is included in the appendices of
this document.
This protocol unavoidably has a mix of both base64 encoded data (as
is normal for many JSON encoded protocols), and also BASE64URL
encoded data, as specified by JWS. The latter is indicated by a
string like "BASE64URL(content-name)".
3. Scope of Solution
3.1. Supported Environments and Use Case Examples
BRSKI-PRM is applicable to scenarios where pledges may have no direct
connection to the domain registrar, may have no continuous
connection, or require coordination of the pledge requests to be
provided to a domain registrar.
This can be motivated by pledges deployed in environments not yet
connected to the operational customer domain network, e.g., at a
building construction site, or environments intentionally
disconnected from the Internet, e.g., critical industrial facilities.
Another example is the assembly of electrical cabinets, which are
prepared in advance before the installation at a customer domain.
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3.1.1. Building Automation
In building automation a typical use case exists where a detached
building or the basement is equipped with sensors, actuators, and
controllers, but with only limited or no connection to the central
building management system. This limited connectivity may exist
during installation time or also during operation time.
During the installation, for instance, a service technician collects
the device-specific information from the basement network and
provides them to the central building management system. This could
be done using a laptop, common mobile device, or dedicated
commissioning tool to transport the information. The service
technician may successively collect device-specific information in
different parts of the building before connecting to the domain
registrar for bulk bootstrapping.
A domain registrar may be part of the central building management
system and already be operational in the installation network. The
central building management system can then provide operational
parameters for the specific devices in the basement or other detached
areas. These operational parameters may comprise values and settings
required in the operational phase of the sensors/actuators, among
them a certificate issued by the operator to authenticate against
other components and services. These operational parameters are then
provided to the devices in the basement facilitated by the service
technician's laptop. The Registrar-Agent, defined in this document,
may be run on the technician's laptop to interact with pledges.
3.1.2. Infrastructure Isolation Policy
This refers to any case in which the network infrastructure is
normally isolated from the Internet as a matter of policy, most
likely for security reasons. In such a case, limited access to a
domain registrar may be allowed in carefully controlled short periods
of time, for example when a batch of new devices are deployed, but
prohibited at other times.
3.1.3. Less Operational Security in the Target-Domain
The registration authority (RA) performing the authorization of a
certificate request is a critical PKI component and therefore
requires higher operational security than other components utilizing
the issued certificates. CAs may also require higher security in the
registration procedures. There may be situations in which the
customer domain does not offer enough physical security to operate a
RA/CA and therefore this service is transferred to a backend that
offers a higher level of operational security.
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3.2. Limitations
The mechanism described in this document presumes the ability of the
pledge and the Registrar-Agent to communicate with another. This may
not be possible in constrained environments where, in particular,
power must be conserved. In these situations, it is anticipated that
the transceiver will be powered down most of the time. This presents
a rendezvous problem: the pledge is unavailable for certain periods
of time, and the Registrar-Agent is similarly presumed to be
unavailable for certain periods of time. To overcome this situation,
the pledges may need to be powered on, either manually or by sending
a trigger signal.
4. Requirements Discussion and Mapping to Solution-Elements
Based on the intended target environment described in Section 3.1,
the following requirements are derived to support bootstrapping of
pledges in responder mode (acting as server):
* To facilitate the communication between a pledge in responder mode
and the registrar, additional functionality is needed either on
the registrar or as a stand-alone component. This new
functionality is defined as Registrar-Agent and acts as an agent
of the registrar to trigger the pledge to generate requests for
voucher and enrollment. These requests are then provided by the
Registrar-Agent to the registrar. This requires the definition of
pledge endpoints to allow interaction with the Registrar-Agent.
* The security of communication between the Registrar-Agent and the
pledge must not rely on Transport Layer Security (TLS) to enable
application of BRSKI-PRM in environments, in which the
communication between the Registrar-Agent and the pledge is done
over other technologies like BTLE or NFC, which may not support
TLS protected communication. In addition, the pledge does not
have a certificate that can easily be verified by [RFC6125]
methods.
* The use of authenticated self-contained objects addresses both,
the TLS challenges and the technology stack challenge.
* By contrast, the Registrar-Agent can be authenticated by the
registrar as a component, acting on behalf of the registrar. In
addition the registrar must be able to verify, which Registrar-
Agent was in direct contact with the pledge.
* It would be inaccurate for the voucher-request and voucher-
response to use an assertion with value "proximity" in the
voucher, as the pledge was not in direct contact with the
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registrar for bootstrapping. Therefore, a new "agent-proximity"
assertion value is necessary for distinguishing assertions the
MASA can state.
At least the following properties are required for the voucher and
enrollment processing:
* POI: provides data-origin authentication of a data object, e.g., a
voucher-request or an enrollment-request, utilizing an existing
IDevID. Certificate updates may utilize the certificate that is
to be updated.
* POP: proves that an entity possesses and controls the private key
corresponding to the public key contained in the certification
request, typically by adding a signature computed using the
private key to the certification request.
Solution examples based on existing technology are provided with the
focus on existing IETF RFCs:
* Voucher-requests and -responses as used in [RFC8995] already
provide both, POP and POI, through a digital signature to protect
the integrity of the voucher, while the corresponding signing
certificate contains the identity of the signer.
* Certification requests are data structures containing the
information from a requester for a CA to create a certificate.
The certification request format in BRSKI is PKCS#10 [RFC2986].
In PKCS#10, the structure is signed to ensure integrity protection
and POP of the private key of the requester that corresponds to
the contained public key. In the application examples, this POP
alone is not sufficient. A POI is also required for the
certification request and therefore the certification request
needs to be additionally bound to the existing credential of the
pledge (IDevID). This binding supports the authorization decision
for the certification request and may be provided directly with
the certification request. While BRSKI uses the binding to TLS,
BRSKI-PRM aims at an additional signature of the PKCS#10 using
existing credentials on the pledge (IDevID). This allows the
process to be independent of the selected transport.
5. Architecture
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5.1. Overview
For BRSKI with pledge in responder mode, the base system architecture
defined in BRSKI [RFC8995] is enhanced to facilitate new use cases in
which the pledge acts as server. The responder mode allows delegated
bootstrapping using a Registrar-Agent instead of a direct connection
between the pledge and the domain registrar.
Necessary enhancements to support authenticated self-contained
objects for certificate enrollment are kept at a minimum to enable
reuse of already defined architecture elements and interactions. The
format of the bootstrapping objects produced or consumed by the
pledge is based on JOSE [RFC7515] and further specified in Section 6
to address the requirements stated in Section 4 above. In
constrained environments it may be provided based on COSE [RFC9052]
and [RFC9053].
An abstract overview of the BRSKI-PRM protocol can be found on slide
8 of [BRSKI-PRM-abstract].
To support mutual trust establishment between the domain registrar
and pledges not directly connected to the customer domain, this
document specifies the exchange of authenticated self-contained
objects with the help of a Registrar-Agent.
This leads to extensions of the logical components in the BRSKI
architecture as shown in Figure 1.
Note that the Join Proxy is not shown in the figure, having been
replaced by Registrar-Agent. In certain situations the Join Proxy
may still be present and could be used by the Registrar-Agent to
connect to the Registrar. For example, a Registrar-Agent application
on a smartphone often can connect to local wifi without giving up
their LTE connection [androidnsd], but only can make link-local
connections.
The Registrar-Agent interacts with the pledge to transfer the
required data objects for bootstrapping, which are then also
exchanged between the Registrar-Agent and the domain registrar. The
addition of the Registrar-Agent influences the sequences of the data
exchange between the pledge and the domain registrar described in
[RFC8995]. To enable reuse of BRSKI defined functionality as much as
possible, BRSKI-PRM:
* uses existing endpoints where the required functionality is
provided.
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* enhances existing endpoints with new supported media types, e.g.,
for JWS voucher.
* defines new endpoints where additional functionality is required,
e.g., for wrapped certification request, CA certificates, or new
status information.
+---------------------------+
..... Drop Ship .....| Vendor Service |
: +---------------+-----------+
: | M anufacturer | |
: | A uthorized | Ownership |
: | S igning | Tracker |
: | A uthority | |
: +---------------+-----------+
: ^
: | BRSKI-
: | MASA
: ...............................|.........
V . v .
+--------+ . +------------+ +-----------+ .
| | . | | | | .
| Pledge | BRSKI- | Registrar- | BRSKI- | Domain | .
| | PRM | Agent | PRM | Registrar | .
| |<------>| |<------>| (PKI RA) | .
| | . | LDevID | | | .
| | . +------------+ +-----+-----+ .
| IDevID | . | .
| | . +------------------+-----+ .
+--------+ . | Key Infrastructure | .
. | (e.g., PKI CA) | .
. +------------------------+ .
.........................................
"Domain" Components
Figure 1: BRSKI-PRM architecture overview using Registrar-Agent
Figure 1 shows the relations between the following main components:
* Pledge: The pledge is expected to respond with the necessary data
objects for bootstrapping to the Registrar-Agent. The protocol
used between the pledge and the Registrar-Agent is assumed to be
HTTP in the context of this document. Any other protocols
(including HTTPS) can be used as long as they support the exchange
of the necessary data objects. This includes CoAP or protocol to
be used over Bluetooth or NFC connections A pledge acting as a
server during bootstrapping leads to some differences for BRSKI:
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- Discovery of the pledge by the Registrar-Agent MUST be
possible.
- As the Registrar-Agent MUST be able to request data objects for
bootstrapping of the pledge, the pledge MUST offer
corresponding endpoints as defined in Section 5.5.
- The Registrar-Agent MUST provide additional data to the pledge
in the context of the voucher-request trigger, which the pledge
MUST include into the PVR as defined in Section 6.1.1 and
Section 6.1.2. This allows the registrar to identify, with
which Registrar-Agent the pledge was in contact.
- The order of exchanges in the BRSKI-PRM call flow is different
those in BRSKI [RFC8995], as the PVR and PER are collected at
once and provided to the registrar. This enables bulk
bootstrapping of several devices.
- The data objects utilized for the data exchange between the
pledge and the registrar are self-contained authenticated
objects (signature-wrapped objects).
* Registrar-Agent: provides a store and forward communication path
to exchange data objects between the pledge and the domain
registrar. The Registrar-Agent brokers in situations in which the
domain registrar is not directly reachable by the pledge. This
may be due to a different technology stack or due to missing
connectivity. The Registrar-Agent triggers a pledge to create
bootstrapping artifacts such as the voucher-request and the
enrollment-request on one or multiple pledges. It can then
perform a (bulk) bootstrapping based on the collected data. The
Registrar-Agent is expected to possess information about the
domain registrar: the registrar EE certificate, LDevID(CA)
certificate, IP address, either by configuration or by using the
discovery mechanism defined in [RFC8995]. There is no trust
assumption between the pledge and the Registrar-Agent as only
authenticated self-contained objects are used, which are
transported via the Registrar-Agent and provided either by the
pledge or the registrar. The trust assumption between the
Registrar-Agent and the registrar is based on the LDevID of the
Registrar-Agent, provided by the PKI responsible for the domain.
This allows the Registrar-Agent to authenticate towards the
registrar, e.g., in a TLS handshake. Based on this, the registrar
is able to distinguish a pledge from a Registrar-Agent during the
TLS session establishment and also to verify that this Registrar-
Agent is authorized to perform the bootstrapping of the distinct
pledge. The Registrar-Agent may be realized as stand-alone
component supporting nomadic activities of a service technician
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moving between different installation sites. Contrary, the
Registrar-Agent may also be realized as co-located functionality
for a registrar, to support pledges in pledge-responder-mode.
* Join Proxy (not shown): same functionality as described in
[RFC8995] if needed. Note that a Registrar-Agent may use a join
proxy to facilitate the TLS connection to the registrar, in the
same way that a BRSKI pledge would use a join proxy. This is
useful in cases where the Registrar-Agent does not have full IP
connectivity via the domain network, or cases where it has no
other means to locate the registrar on the network.
* Domain Registrar: In general, the domain registrar fulfills the
same functionality regarding the bootstrapping of the pledge in a
(customer site) domain by facilitating the communication of the
pledge with the MASA service and the domain PKI service. In
contrast to [RFC8995], the domain registrar does not interact with
a pledge directly but through the Registrar-Agent. A registrar
with combined functionality of BRSKI and BRSKI-PRM detects if the
bootstrapping is performed by the pledge directly (BRSKI case) or
by the Registrar-Agent (BRSKI-PRM case) based on the utilized
credential for authentication (either pledge’s IDevID or LDevID
from Registrar-Agent), see also Section 6.2.
* The manufacturer provided components/services (MASA and Ownership
tracker) are used as defined in [RFC8995]. A MASA is able to
support enrollment via Registrar-Agent without changes unless it
checks the vouchers proximity indication, in which case it would
need to be enhanced to support BRSKI-PRM to also accept the agent-
proximity.
5.2. Nomadic connectivity
In one example instance of the PRM architecture as shown in Figure 2,
there is no connectivity between the location in which the pledge is
installed and the location of the domain registrar. This is often
the case in the aforementioned building automation use case
(Section 3.1.1).
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+---------------------------+
..... Drop Ship .....| Vendor Service |
: +---------------------------+
: ^
........................................ |
. v . |
. +--------+ .-.-.-.-.-.-.-. . |
. | | : Registrar- : . |
. | Pledge |<--------->: Agent : . |
. +--------+ L2 or L3 :-.-.-.-.-.-.-: . |
. connectivity ^ . |
..........................!............. |
Pledge install ! |
location ! Nomadic |
! connectivity |
! |
...........!...................|.........
. v v .
. .-.-.-.-.-.-.-. +-----------+ .
. : Registrar- : | Domain | .
. : Agent :<----->| Registrar | .
. :-.-.-.-.-.-.-: +-----+-----+ .
. | .
. +------------------+-----+ .
. | Key Infrastructure | .
. | (e.g., PKI CA) | .
. +------------------------+ .
.........................................
"Domain" Components
Figure 2: Registrar-Agent nomadic connectivity example
PRM enables support of this case through nomadic connectivity of the
Registrar-Agent. To perform enrollment in this setup, multiple round
trips of the Registrar-Agent between the pledge install location and
the domain registrar are required.
1. Connectivity to domain registrar: preparation tasks for pledge
bootstrapping not part of the BRSKI-PRM protocol definition, like
retrieval of list of pledges to enroll.
2. Connectivity to pledge install location: retrieve information
about available pledges (IDevID), collect request objects like
voucher-requests and enrollment-requests using the BRSKI-PRM
approach described in Section 6.1.
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3. Connectivity to domain registrar, submit collected pledges'
request information, retrieve response objects as voucher and
enrollment information using the BRSKI-PRM approach described in
Section 6.2.
4. Connectivity to pledge install location, provide retrieved
objects to the pledge to enroll pledges and collect status using
the BRSKI-PRM approach described in Section 6.3.
5. Connectivity to domain registrar, submit voucher status and
enrollment status using the BRSKI-PRM approach described in
Section 6.3.6.
Variations of this setup include cases where the Registrar-Agent uses
for example WiFi to connect to the pledge installation network, and
mobile network connectivity to connect to the domain registrar. Both
connections may also be possible in a single location at the same
time, based on installation building conditions.,
5.3. Registrar-Agent co-located with registrar
Compared to [RFC8995] BRSKI, pledges supporting BRSKI-PRM can be
completely passive and only need to react when being requested to
react by a Registrar-Agent. In [RFC8995], pledges instead need to
continuously request enrollment from a domain registrar, which may
result in undesirable communications pattern and possible overload of
a domain registrar.
+---------------------------+
..... Drop Ship .....| Vendor Service |
: +---------------------------+
: ^
: |
: ...............................|.........
: . v .
v . +-------------------------+ .
+--------+ . |.............. | .
| | . |. Registrar- . Domain | .
| Pledge |<------------->|. Agent . Registrar | .
+--------+ L2 or L3 |.............. | .
connectivity +-------------------+-----+ .
. | .
. +------------------+-----+ .
. | Key Infrastructure | .
. +------------------------+ .
.........................................
"Domain" Components
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Figure 3: Registrar-Agent integrated into Domain Registrar example
The benefits of BRSKI-PRM can be achieved even without the
operational complexity of standalone Registrar-Agents by integrating
the necessary functionality of the Registrar-Agent as a module into
the domain registrar as shown in Figure 3 so that it can support the
BRSKI-PRM communications to the pledge.
5.4. Agent-Proximity Assertion
"Agent-proximity" is a statement in the PVR and in the voucher, that
the registrar certificate was provided via the Registrar-Agent as
defined in Section 6 and not directly to the pledge. "Agent-
proximity" is therefore a different assertion then "proximity", which
is defined in section 4 of [RFC8366]. "Agent-proximity" is defined
as additional assertion type in [I-D.ietf-anima-rfc8366bis]. This
can be verified by the registrar and also by the MASA during the
voucher-request processing.
In BRSKI, the pledge verifies POP of the registrar via the TLS
handshake and pins that public key as the "proximity-registrar-cert"
into the voucher request. This allows the MASA to verify the
proximity of the pledge and registrar, facilitating a decision to
assign the pledge to that domain owner. In BRSKI, the TLS connection
is considered provisional until the pledge receives the voucher.
In contrast, in BRSKI-PRM, the pledge has no direct connection to the
registrar and must take the Registrar-Agent LDevID provisionally.
The Registrar-Agent has included its LDevID, a certificate signed by
the domain owner, into the PVR trigger message. The Registrar-Agent
identity is therefore included into the Pledge Voucher Request (PVR).
Akin to the BRSKI case, the pledge has provided proximity evidence to
the MASA. But additionally, this allows the Registrar to be sure
that the PVR collected by the Registrar-Agent was in fact collected
by the Registrar-Agent to which the Registrar is connected to.
In a similar fashion, the pledge accepts the registrar certificate
provisionally until it receives the voucher as described in
Section 6.3. See also Section 5 of [RFC8995] on "PROVISIONAL accept
of server cert".
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5.5. Behavior of Pledge in Pledge-Responder-Mode
The pledge is triggered by the Registrar-Agent to generate the PVR
and PER. It will also be triggered for processing of the responses
and the generation of status information once the Registrar-Agent has
received the responses from the registrar later in the process. Due
to the use of the Registrar-Agent, the interaction with the domain
registrar is changed as shown in Figure 5. To enable interaction as
responder with the Registrar-Agent, the pledge provides endpoints
using the BRSKI defined endpoints based on the "/.well-known/brski"
URI tree.
When the Registrar-Agent reaches out to a pledge, for instance with
an example URI path "http://pledge.example/.well-known/brski/tpvr",
it will in fact send a Host: header of "pledge.example", with a
relative path of "/.well-known/brski/tpbr". However in practice the
pledge will often be known only by its IP address as returned by a
discovery protocol, and that is what will be present in the Host:
header.
The pledge MUST respond to all queries regardless of what Host:
header is provided by the client. [RFC9110], Section 7.2 makes the
Host: header mandatory, so it will always be present.
The following operations are defined for the _pledge_ in this
document, describing their endpoints and their corresponding URIs.
The endpoints are defined with short names to also accommodate for
the constraint case.
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+======================================+==========+=========+
| Operation | Endpoint | Details |
+======================================+==========+=========+
| Trigger pledge voucher-request | /tpvr | Section |
| creation - Returns PVR | | 6.1 |
+--------------------------------------+----------+---------+
| Trigger pledge enrollment-request - | /tper | Section |
| Returns PER | | 6.1 |
+--------------------------------------+----------+---------+
| Supply voucher to pledge - Returns | /svr | Section |
| pledge voucher-status | | 6.3 |
+--------------------------------------+----------+---------+
| Supply enrollment-response to pledge | /ser | Section |
| - Returns pledge enrollment-status | | 6.3 |
+--------------------------------------+----------+---------+
| Supply CA certs to pledge | /scac | Section |
| | | 6.3 |
+--------------------------------------+----------+---------+
| Query status of pledge - Returns | /qps | Section |
| pledge-status | | 6.4 |
+--------------------------------------+----------+---------+
Table 1: Endpoints on the pledge
5.6. Behavior of Registrar-Agent
The Registrar-Agent as a new component provides a message passing
service between the pledge and the domain registrar. It facilitates
the exchange of data between the pledge and the domain registrar,
which are the voucher-request/response, the enrollment-request/
response, as well as related telemetry and status information.
For the communication with the pledge the Registrar-Agent utilizes
communication endpoints provided by the pledge. The transport in
this specification is based on HTTP but may also be done using other
transport mechanisms.
The communication between the Registrar-Agent and the pledge MAY be
protected using TLS as outlined in Section 6.1. The details of doing
TLS validation are Appendix B.
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For the communication with the registrar, the Registrar-Agent uses
the endpoints of the domain registrar side already specified in
[RFC8995] (derived from EST [RFC7030]) where suitable. These
endpoints do not expect signature wrapped-objects, which are used b
BRSKI-PRM. This specifically applies for the enrollment-request and
the provisioning of CA certificates. To accommodate the use of
signature-wrapped object, the following additional endpoints are
defined for the _registrar_. Operations and their corresponding URIs:
+===================================+=================+=========+
| Operation | Endpoint | Details |
+===================================+=================+=========+
| Supply PER to registrar - Returns | /requestenroll | Section |
| enrollment-response | | 6.2.6 |
+-----------------------------------+-----------------+---------+
| Request (wrapped) CA certificates | /wrappedcacerts | Section |
| - Returns wrapped CA Certificates | | 6.2.7 |
+-----------------------------------+-----------------+---------+
Table 2: Additional endpoints on the registrar
For authentication to the domain registrar, the Registrar-Agent uses
its EE (RegAgt) certificate. The provisioning of the Registrar-Agent
LDevID is out of scope for this document, but may be done in advance
using a separate BRSKI run or by other means like configuration. It
is recommended to use short lived Registrar-Agent LDevIDs in the
range of days or weeks as outlined in Section 10.3.
The Registrar-Agent will use its EE certificate when establishing a
TLS session with the domain registrar for TLS client authentication.
The EE (RegAgt) certificate MUST include a SubjectKeyIdentifier
(SKID), which is used as reference in the context of an agent-signed-
data object as defined in Section 6.1. Note that this is an
additional requirement for issuing the certificate, as [IEEE-802.1AR]
only requires the SKID to be included for intermediate CA
certificates. [RFC8995] makes a similar requirement. In BRSKI-PRM,
the SKID is used in favor of providing the complete EE (RegAgt)
certificate to accommodate also constraint environments and reduce
bandwidth needed for communication with the pledge. In addition, it
follows the recommendation from BRSKI to use SKID in favor of a
certificate fingerprint to avoid additional computations.
Using an LDevID for TLS client authentication of the Registrar-Agent
is a deviation from [RFC8995], in which the pledge's IDevID
credential is used to perform TLS client authentication. The use of
the EE (RegAgt) certificate allows the domain registrar to
distinguish, if bootstrapping is initiated from a pledge or from a
Registrar-Agent and to adopt different internal handling accordingly.
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If a registrar detects a request that originates from a Registrar-
Agent it is able to switch the operational mode from BRSKI to BRSKI-
PRM. This may be supported by a specific naming in the SAN (subject
alternative name) component of the EE (RegAgt) certificate.
Alternatively, the domain may feature a CA specifically for issuing
Registrar-Agent LDevID certificates. This allows the registrar to
detect Registrar-Agents based on the issuing CA.
As BRSKI-PRM uses authenticated self-contained data objects between
the pledge and the domain registrar, the binding of the pledge
identity to the requests is provided by the data object signature
employing the pledge's IDevID. The objects exchanged between the
pledge and the domain registrar used in the context of this
specifications are JOSE objects.
In addition to the EE (RegAgt) certificate, the Registrar-Agent is
provided with the product-serial-number(s) of the pledge(s) to be
bootstrapped. This is necessary to allow the discovery of pledge(s)
by the Registrar-Agent using DNS-SD with mDNS (see Section 5.6.2) The
list may be provided by prior administrative means or the Registrar-
Agent may get the information via an interaction with the pledge.
For instance, [RFC9238] describes scanning of a QR code, the product-
serial-number would be initialized from the 12N B005 Product Serial
Number.
According to [RFC8995] section 5.3, the domain registrar performs the
pledge authorization for bootstrapping within his domain based on the
pledge voucher-request object. This behavior is retained also in
BRSKI-PRM.
The following information MUST be available at the Registrar-Agent
before interaction with a pledge:
* EE (RegAgt) certificate and corresponding private key: own
operational key pair (to sign agent-signed-data).
* Registrar EE certificate: certificate of the domain registrar (to
be provided to the pledge).
* Serial-number(s): product-serial-number(s) of pledge(s) to be
bootstrapped (to query discovery of specific pledges based on the
product-serial-number).
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5.6.1. Discovery of Registrar by Registrar-Agent
As a Registrar-Agent acts as representative of the domain registrar
towards the pledge or may even be collocated with the domain
registrar, a separate discovery of the registrar is likely not needed
as Registrar-Agent and registrar are domain components and have a
trust relation. Moreover, other communication (not part of this
document) between the Registrar-Agent and the registrar is assumed,
e.g., to exchange information about product-serial-number(s) of
pledges to be discovered as outlined in Section 5.2. Moreover, as
the standard discovery described in section 4 and the appendix A.2 of
[RFC8995] does not support of registrars with an enhanced feature set
(like the support of BRSKI-PRM), this standard discovery is not
applicable.
As a more general solution, the BRSKI discovery mechanism can be
extended to provide upfront information on the capabilities of
registrars, such as the mode of operation (pledge-responder-mode or
registrar-responder-mode). Defining discovery extensions is out of
scope of this document. This may be provided in
[I-D.eckert-anima-brski-discovery].
5.6.2. Discovery of Pledge by Registrar-Agent
The discovery of the pledge by Registrar-Agent in the context of this
document describes the minimum discovery approach to be supported. A
more general discovery mechanism, also supporting GRASP besides DNS-
SD with mDNS may be provided in [I-D.eckert-anima-brski-discovery].
Discovery in BRSKI-PRM uses DNS-based Service Discovery [RFC6763]
over Multicast DNS [RFC6762] to discover the pledge. Note that
[RFC6762] Section 9 provides support for conflict resolution in
situations when an DNS-SD with mDNS responder receives a mDNS
response with inconsistent data. Note that [RFC8990] does not
support conflict resolution of mDNS, which may be a limitation for
its application.
The pledge constructs a local host name based on device local
information (product-serial-number), which results in "product-
serial-number._brski-pledge._tcp.local". The product-serial-number
composition is manufacturer dependent and may contain information
regarding the manufacturer, the product type, and further information
specific to the product instance. To allow distinction of pledges,
the product-serial-number therefore needs to be sufficiently unique.
In the absence of a more general discovery as defined in
[I-D.eckert-anima-brski-discovery] the Registrar-Agent MUST use
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* "product-serial-number._brski-pledge._tcp.local", to discover a
specific pledge, e.g., when connected to a local network.
* "_brski-pledge._tcp.local" to get a list of pledges to be
bootstrapped.
A manufacturer may allow the pledge to react on DNS-SD with mDNS
discovery without his product-serial-number contained. This allows a
commissioning tool to discover pledges to be bootstrapped in the
domain. The manufacturer support this functionality as outlined in
Section 10.4.
Establishing network connectivity of the pledge is out of scope of
this document but necessary to apply DNS-SD with mDNS. For Ethernet
it is provided by simply connecting the network cable. For WiFi
networks, connectivity can be provided by using a pre-agreed SSID for
bootstrapping, e.g., as proposed in
[I-D.richardson-emu-eap-onboarding]. The same approach can be used
by 6LoWPAN/mesh using a pre-agreed PAN ID. How to gain network
connectivity is out of scope of this document.
5.7. Behavior of Pledge with Combined Functionality
Pledges MAY support both initiator or responder mode.
A pledge in initiator mode should listen for announcement messages as
described in Section 4.1 of [RFC8995]. Upon discovery of a potential
registrar, it initiates the bootstrapping to that registrar. At the
same time (so as to avoid the Slowloris-attack described in
[RFC8995]), it SHOULD also respond to the triggers for responder mode
described in this document.
Once a pledge with combined functionality has been bootstrapped, it
MAY act as client for enrollment of further certificates needed,
e.g., using the enrollment protocol of choice. If it still acts as
server, the defined BRSKI-PRM endpoints to trigger a pledge
enrollment-request (PER) or to provide an enrollment-response can be
used for further certificates.
6. Bootstrapping Data Objects and Corresponding Exchanges
The interaction of the pledge with the Registrar-Agent may be
accomplished using different transport means (protocols and/or
network technologies). This specification utilizes HTTP as
transport. Alternative transport channels may be CoAP, Bluetooth Low
Energy (BLE), or Nearfield Communication (NFC). These transport
means may differ from, and are independent of, the ones used between
the Registrar-Agent and the registrar. Transport channel
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independence is realized by data objects, which are not bound to
specific transport security and stay the same across the
communication from the pledge via the Registrar-Agent to the
registrar.. Therefore, authenticated self-contained objects (here:
signature-wrapped objects) are applied for data exchanges between the
pledge and the registrar.
The Registrar-Agent provides the domain registrar certificate
(registrar LDevID certificate) to the pledge to be included in the
PVR leaf "agent-provided-proximity-registrar-certificate". This
enables the registrar to verify that it is the desired registrar for
handling the request.
The registrar certificate may be configured at the Registrar-Agent or
may be fetched by the Registrar-Agent based on a prior TLS connection
with this domain registrar. In addition, the Registrar-Agent
provides agent-signed-data containing the pledge product-serial-
number, signed with the private key corresponding to the EE (RegAgt)
certificate, as described in Section 6.1. This enables the registrar
to verify and log, which Registrar-Agent was in contact with the
pledge, when verifying the PVR.
The registrar MUST provide the EE (RegAgt) certificate identified by
the SubjectKeyIdentifier (SKID) in the header of the agent-signed-
data from the PVR in its RVR (see also Section 6.2.2.
The MASA in turn verifies the registrar LDevID certificate is
included in the PVR (contained in the "prior-signed-voucher-request"
field of RVR) in the "agent-provided-proximity-registrar-certificate"
leaf and may assert the PVR as "verified" or "logged".
In addition, the MASA MAY issue the assertion "agent-proximity" as
follows: The MASA verifies the signature of the agent-signed-data
contained in the prior-signed-voucher-request, based on the provided
EE (RegAgt) certificate in the "agent-sign-cert" leaf of the RVR. If
both can be verified successfully, the MASA can assert "agent-
proximity" in the voucher. The assertion of "agent-proximity" is
similar to the proximity assertion by the MASA when using BRSKI.
Note that the different assertions do not provide a metric of
strength as the security properties are not comparable.
Depending on the MASA verification policy, it may also respond with a
suitable 4xx or 5xx error status code as described in section 5.6 of
[RFC8995]. When successful, the voucher will then be supplied via
the registrar to the Registrar-Agent.
Figure 4 provides an overview of the exchanges detailed in the
following sub sections.
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+--------+ +-----------+ +-----------+ +--------+ +---------+
| Pledge | | Registrar-| | Domain | | Domain | | Vendor |
| | | Agent | | Registrar | | CA | | Service |
| | | (RegAgt) | | (JRC) | | | | (MASA) |
+--------+ +-----------+ +-----------+ +--------+ +---------+
| | | | Internet |
| discover | | | |
| pledge | | | |
| mDNS query | | | |
|<---------------| | | |
|--------------->| | | |
| | | | |
(1) trigger PVR (tPVR) and PER (tPER) generation on pledge
|<--opt. TLS --->| | | |
|<----- tPVR ----| | | |
|------ PVR ---->| | | |
| | | | |
|<----- tPER ----| | | |
|------ PER ---->| | | |
~ ~ ~ ~ ~
(2) provide PVR to infrastructure
| |<----- TLS ----->| | |
| | [Reg-Agt authenticated | |
| | and authorized?] | |
| |----- PVR ------>| | |
| | [Reg-Agt authorized?] | |
| | [accept device?] | |
| | [contact vendor] | |
| | |------------ RVR --------->|
| | | [extract DomainID]
| | | [update audit log]
| | |<--------- Voucher --------|
| |<--- Voucher ----| | |
| | | | |
(2) provide PER to infrastructure
| |------ PER ----->| | |
| | |---- CSR ---->| |
| | |<--- Cert ----| |
| |<--Enroll-Resp---| | |
| | | | |
(2) query cACerts from infrastructure
| |-- cACert-Req -->| | |
| |<-- cACert-Resp--| | |
~ ~ ~ ~ ~
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(3) provide voucher and certificate and collect status info
|<--opt. TLS --->| | | |
|<--- Voucher ---| | | |
|---- vStatus -->| | | |
|<--- cACerts ---| | | |
|<--Enroll-Resp--| | | |
|--- eStatus --->| | | |
~ ~ ~ ~ ~
(4) provide voucher status and enroll status to registrar
| |<------ TLS ---->| | |
| |---- vStatus -->| | |
| | |--- req device audit log-->|
| | |<---- device audit log ----|
| | [verify audit log]
| | | | |
| |---- eStatus --->| | |
| | | | |
Figure 4: Overview pledge-responder-mode exchanges
The following sub sections split the interactions shown in Figure 4
between the different components into:
1. Section 6.1 describes the request object acquisition by the
Registrar-Agent from pledge.
2. Section 6.2 describes the request object processing initiated by
the Registrar-Agent to the registrar and also the interaction of
the registrar with the MASA and the domain CA including the
response object processing by these entities.
3. Section 6.3 describes the supply of response objects between the
Registrar-Agent and the pledge including the status information.
4. Section 6.4 describes the general status handling and addresses
corresponding exchanges between the Registrar-Agent and the
registrar.
6.1. Request Objects Acquisition by Registrar-Agent from Pledge
The following description assumes that the Registrar-Agent has
already discovered the pledge. This may be done as described in
Section 5.6.2 and Figure 4 based on DNS-SD or similar.
The focus is on the exchange of signature-wrapped objects using
endpoints defined for the pledge in Section 5.5.
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Preconditions:
* Pledge: possesses IDevID
* Registrar-Agent:
- possesses own credentials (EE (RegAgt) certificate and
corresponding private key) for the registrar domain.
- MAY possess the IDevID CA certificate of the pledge vendor/
manufacturer to validate IDevID certificate on returned PVR or
in case of TLS usage for pledge communication. The
distribution of IDevID CA certificates to the Registrar-Agent
is out of scope of this document and may be done by a manual
configuration. In addition, the Registrar-Agent SHOULD know
the product-serial-number(s) of the pledge(s) to be
bootstrapped. The Registrar-Agent MAY be provided with the
product-serial-number(s) in different ways:
o configured, e.g., as a list of pledges to be bootstrapped
via QR code scanning
o discovered by using standard approaches like DNS-SD with
mDNS as described in Section 5.6.2
o discovered by using a manufacturer specific approach, e.g.,
RF beacons. If the product-serial-number(s) are not known
in advance, the Registrar-Agent cannot perform a distinct
triggering of pledges but and triggers all pledges
discovered .
The Registrar-Agent SHOULD have synchronized time.
* Registrar (same as in BRSKI): possesses/trusts IDevID CA
certificate and has own registrar EE credentials.
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+--------+ +-----------+
| Pledge | | Registrar-|
| | | Agent |
| | | (RegAgt) |
+--------+ +-----------+
| |-create
| | agent-signed-data
|<-- optional establish TLS connection --|
| |
|<--- trigger pledge voucher-request ----|
|-agent-provided-proximity-registrar-cert|
|-agent-signed-data |
| |
|----- pledge voucher-request ---------->|-store PVR
| |
|<----- trigger enrollment-request ------|
| (empty) |
| |
|------ pledge enrollment-request ------>|-store (PER)
| |
Figure 5: Request collection (Registrar-Agent - pledge)
TLS MAY be optionally used to provide privacy for the interaction
between the Registrar-Agent and the pledge, see Appendix B.
Note: The Registrar-Agent may trigger the pledge for the PVR or the
PER or both. It is expected that this will be aligned with a service
technician workflow, visiting and installing each pledge.
6.1.1. Pledge-Voucher-Request (PVR) - Trigger
Triggering the pledge to create the PVR is done using HTTP POST on
the defined pledge endpoint: "/.well-known/brski/tpvr"
The Registrar-Agent PVR trigger Content-Type header is: application/
json. Following parameters are provided in the JSON object:
* agent-provided-proximity-registrar-cert: base64-encoded registrar
EE TLS certificate.
* agent-signed-data: base64-encoded JSON-in-JWS object.
The trigger for the pledge to create a PVR is depicted in the
following figure:
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{
"agent-provided-proximity-registrar-cert": "base64encodedvalue==",
"agent-signed-data": "base64encodedvalue=="
}
Figure 6: Representation of trigger to create PVR
Note that at the time of receiving the PVR trigger, the pledge cannot
verify the registrar LDevID certificate and has no proof-of-
possession of the corresponding private key for the certificate. The
pledge therefore accepts the registrar LDevID certificate
provisionally until it receives the voucher as described in
Section 6.3.
The pledge will also be unable to verify the agent-signed-data itself
as it does not possess the EE (RegAgt) certificate and the domain
trust has not been established at this point of the communication.
Verification SHOULD be done, after the voucher has been received.
The agent-signed-data is a JSON-in-JWS object and contains the
following information:
The header of the agent-signed-data contains:
* alg: algorithm used for creating the object signature.
* kid: MUST contain the base64-encoded bytes of the
SubjectKeyIdentifier (the "KeyIdentifier" OCTET STRING value) of
the EE (RegAgt) certificate.
The body of the agent-signed-data contains an "ietf-voucher-
request:agent-signed-data" element (defined in
[I-D.ietf-anima-rfc8366bis]):
* created-on: MUST contain the creation date and time in yang:date-
and-time format.
* serial-number: MUST contain the product-serial-number as type
string as defined in [RFC8995], section 2.3.1. The serial-number
corresponds with the product-serial-number contained in the
X520SerialNumber field of the IDevID certificate of the pledge.
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# The agent-signed-data in General JWS Serialization syntax
{
"payload": "BASE64URL(ietf-voucher-request-prm:agent-signed-data)",
"signatures": [
{
"protected": "BASE64URL(UTF8(JWS Protected Header))",
"signature": BASE64URL(JWS Signature)
}
]
}
# Example: Decoded payload representation in JSON syntax of
"ietf-voucher-request-prm:agent-signed-data"
"ietf-voucher-request-prm:agent-signed-data": {
"created-on": "2021-04-16T00:00:01.000Z",
"serial-number": "callee4711"
}
# Example: Decoded "JWS Protected Header" representation
in JSON syntax
{
"alg": "ES256",
"kid": "base64encodedvalue=="
}
Figure 7: Representation of agent-signed-data in General JWS
Serialization syntax
6.1.2. Pledge-Voucher-Request (PVR) - Response
Upon receiving the voucher-request trigger, the pledge SHALL
construct the body of the PVR as defined in [RFC8995]. It will
contain additional information provided by the Registrar-Agent as
specified in the following. This PVR becomes a JSON-in-JWS object as
defined in [I-D.ietf-anima-jws-voucher]. If the pledge is unable to
construct the PVR it SHOULD respond with a HTTP error code to the
Registrar-Agent to indicate that it is not able to create the PVR.
The following client error responses MAY be used:
* 400 Bad Request: if the pledge detected an error in the format of
the request, e.g. missing field, wrong data types, etc. or if the
request is not valid JSON even though the PVR media type was set
to application/json.
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* 403 Forbidden: if the pledge detected that one or more security
parameters from the trigger message to create the PVR were not
valid, e.g., the LDevID (Reg) certificate.
The header of the PVR SHALL contain the following parameters as
defined in [RFC7515] to support JWS signing of the object:
* alg: algorithm used for creating the object signature.
* x5c: contains the base64-encoded pledge IDevID certificate. It
MAY optionally contain the certificate chain for this certificate.
If the certificate chain is not included it MUST be available at
the registrar for verification of the IDevID certificate.
The payload of the PVR MUST contain the following parameters as part
of the ietf-voucher-request-prm:voucher as defined in [RFC8995]:
* created-on: SHALL contain the current date and time in yang:date-
and-time format. If the pledge does not have synchronized time,
it SHALL use the created-on time from the agent-signed-data,
received in the trigger to create a PVR.
* nonce: SHALL contain a cryptographically strong pseudo-random
number.
* serial-number: SHALL contain the pledge product-serial-number as
X520SerialNumber.
* assertion: SHALL contain the requested voucher assertion "agent-
proximity" (different value as in RFC 8995)..
The ietf-voucher-request:voucher is extended with additional
parameters:
* agent-provided-proximity-registrar-cert: MUST be included and
contains the base64-encoded registrar LDevID certificate (provided
as PVR trigger parameter by the Registrar-Agent).
* agent-signed-data: MUST contain the base64-encoded agent-signed-
data (as defined in Figure 7) and provided as a PVR trigger
parameter by the Registrar-Agent.
The enhancements of the YANG module for the ietf-voucher-request with
these new leaves are defined in [I-D.ietf-anima-rfc8366bis].
The PVR is signed using the pledge's IDevID credential contained as
x5c parameter of the JOSE header.
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# The PVR in General JWS Serialization syntax
{
"payload": "BASE64URL(ietf-voucher-request-prm:voucher)",
"signatures": [
{
"protected": "BASE64URL(UTF8(JWS Protected Header))",
"signature": BASE64URL(JWS Signature)
}
]
}
# Example: Decoded Payload "ietf-voucher-request-prm:voucher"
representation in JSON syntax
"ietf-voucher-request-prm:voucher": {
"created-on": "2021-04-16T00:00:02.000Z",
"nonce": "eDs++/FuDHGUnRxN3E14CQ==",
"serial-number": "callee4711",
"assertion": "agent-proximity",
"agent-provided-proximity-registrar-cert": "base64encodedvalue==",
"agent-signed-data": "base64encodedvalue=="
}
# Example: Decoded "JWS Protected Header" representation
in JSON syntax
{
"alg": "ES256",
"x5c": [
"base64encodedvalue==",
"base64encodedvalue=="
],
"typ": "voucher-jws+json"
}
Figure 8: Representation of PVR
The PVR Media-Type is defined in [I-D.ietf-anima-jws-voucher] as
application/voucher-jws+json.
The pledge MUST include this Media-Type header field indicating the
included media type for the PVR. The PVR is included by the
registrar in its RCR as described in Section 6.2.
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6.1.3. Pledge-Enrollment-Request (PER) - Trigger
Once the Registrar-Agent has received the PVR it can trigger the
pledge to generate a PER. As in BRSKI the PER contains a PKCS#10,
but additionally signed using the pledge's IDevID. Note, as the
initial enrollment aims to request a generic certificate, no
certificate attributes are provided to the pledge.
Triggering the pledge to create the enrollment-request is done using
HTTP POST on the defined pledge endpoint: "/.well-known/brski/tper"
The Registrar-Agent PER trigger Content-Type header is: application/
json with an empty body by default. Note that using HTTP POST allows
for an empty body, but also to provide additional data, like CSR
attributes or information about the enroll type "enroll-generic-cert"
or "re-enroll-generic-cert". The "enroll-generic-cert" case is shown
in Figure 9.
{
"enroll-type" : "enroll-generic-cert"
}
Figure 9: Example of trigger to create a PER
This document specifies the request of a generic certificate with no
CSR attributes provided to the pledge. If specific attributes in the
certificate are required, they have to be inserted by the issuing RA/
CA. How the HTTP POST can be used to provide CSR attributes is out
of scope for this specification.
6.1.4. Pledge-Enrollment-Request (PER) - Response
In the following the enrollment is described as initial enrollment
with an empty HTTP POST body.
Upon receiving the PER trigger, the pledge SHALL construct the PER as
authenticated self-contained object. The CSR already assures POP of
the private key corresponding to the contained public key. In
addition, based on the PER signature using the IDevID, POI is
provided. Here, a JOSE object is being created in which the body
utilizes the YANG module ietf-ztp-types with the grouping for csr-
grouping for the CSR as defined in [I-D.ietf-netconf-sztp-csr].
Depending on the capability of the pledge, it constructs the pledge
enrollment-request (PER) as plain PKCS#10. Note, the focus in this
use case is placed on PKCS#10 as PKCS#10 can be transmitted in
different enrollment protocols in the infrastructure like EST, CMP,
CMS, and SCEP. If the pledge has already implemented an enrollment
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protocol, it may leverage that functionality for the creation of the
CSR. Note, [I-D.ietf-netconf-sztp-csr] also allows for inclusion of
certification requests in different formats used by CMP or CMC.
The pledge MUST construct the PER as PKCS#10. In BRSKI-PRM it MUST
sign it additionally with its IDevID credentials to provide proof-of-
identity bound to the PKCS#10 as described below.
If the pledge is unable to construct the PER it SHOULD respond with a
HTTP 4xx/5xx error code to the Registrar-Agent to indicate that it is
not able to create the PER.
The following 4xx client error codes MAY be used:
* 400 Bad Request: if the pledge detected an error in the format of
the request or detected invalid JSON even though the PER media
type was set to application/json.
* 403 Forbidden: if the pledge detected that one or more security
parameters (if provided) from the trigger message to create the
PER are not valid.
* 406 Not Acceptable: if the request's Accept header indicates a
type that is unknown or unsupported. For example, a type other
than application/jose+json.
* 415 Unsupported Media Type: if the request's Content-Type header
indicates a type that is unknown or unsupported. For example, a
type other than 'application/json'.
A successful enrollment will result in a generic LDevID certificate
for the pledge in the new domain, which can be used to request
further (application specific) LDevID certificates if necessary for
operation. The Registrar-Agent SHALL use the endpoints specified in
this document.
[I-D.ietf-netconf-sztp-csr] considers PKCS#10 but also CMP and CMC as
certification request format. Note that the wrapping of the PER
signature is only necessary for plain PKCS#10 as other request
formats like CMP and CMS support the signature wrapping as part of
their own certificate request format.
The Registrar-Agent enrollment-request Content-Type header for a
signature-wrapped PKCS#10 is: application/jose+json
The header of the pledge enrollment-request SHALL contain the
following parameter as defined in [RFC7515]:
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* alg: algorithm used for creating the object signature.
* x5c: contains the base64-encoded pledge IDevID certificate. It
MAY optionally contain the certificate chain for this certificate.
If the certificate chain is not included it MUST be available at
the registrar for verification of the IDevID certificate. The
body of the pledge enrollment-request SHOULD contain a P10
parameter (for PKCS#10) as defined for ietf-ztp-types:p10-csr in
[I-D.ietf-netconf-sztp-csr]:
* P10: contains the base64-encoded PKCS#10 of the pledge.
The JOSE object is signed using the pledge's IDevID credential, which
corresponds to the certificate signaled in the JOSE header.
While BRSKI-PRM targets the initial enrollment, re-enrollment SHOULD
be supported as described in a similar way as for enrollment in this
document, if no other re-enrollment mechanism is supported. Note
that in this case the current LDevID credential is used instead of
the IDevID credential to create the signature of the PKCS#10 request.
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# The PER in General JWS Serialization syntax
{
"payload": "BASE64URL(ietf-ztp-types)",
"signatures": [
{
"protected": "BASE64URL(UTF8(JWS Protected Header))",
"signature": BASE64URL(JWS Signature)
}
]
}
# Example: Decoded Payload "ietf-ztp-types" Representation
in JSON Syntax
"ietf-ztp-types": {
"p10-csr": "base64encodedvalue=="
}
# Example: Decoded "JWS Protected Header" Representation
in JSON Syntax
{
"alg": "ES256",
"x5c": [
"base64encodedvalue==",
"base64encodedvalue=="
],
"crit":["created-on"],
"created-on": "2022-09-13T00:00:02.000Z"
}
Figure 10: Representation of PER
With the collected PVR and PER, the Registrar-Agent starts the
interaction with the domain registrar.
The new protected header field "created-on" is introduced to reflect
freshness of the PER. The field is marked critical "crit" to ensure
that it must be understood and validated by the receiver (here the
domain registrar) according to section 4.1.11 of [RFC7515]. It
allows the registrar to verify the timely correlation between the PER
and previously exchanged messages, i.e., created-on of PER >=
created-on of PVR >= created-on of PVR trigger. The registrar MAY
consider to ignore any but the newest PER from the same pledge in the
case the registrar has at any point in time more than one pending PER
from the pledge.
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As the Registrar-Agent is intended to facilitate communication
between the pledge and the domain registrar, a collection of requests
from more than one pledge is possible. This allows bulk
bootstrapping of several pledges using the same connection between
the Registrar-Agent and the domain registrar.
6.2. Request Object Handling initiated by the Registrar-Agent on
Registrar, MASA and Domain CA
The BRSKI-PRM bootstrapping exchanges between Registrar-Agent and
domain registrar resemble the BRSKI exchanges between pledge and
domain registrar (pledge-initiator-mode) with some deviations.
Preconditions:
* Registrar-Agent: possesses its own credentials (EE (RegAgt)
certificate and corresponding private key) of the domain. In
addition, it MAY possess the IDevID CA certificate of the pledge
vendor/manufacturer to verify the pledge certificate in the
received request messages. It has the address of the domain
registrar through configuration or by discovery, e.g., DNS-SD with
mDNS. The Registrar-Agent has acquired one or more PVR and PER
objects.
* Registrar (same as in BRSKI): possesses the IDevID CA certificate
of the pledge vendor/manufacturer and its own registrar EE
credentials of the domain.
* MASA (same as in BRSKI): possesses its own vendor/manufacturer
credentials (voucher signing key and certificate, TLS server
certificate and private key) related to pledges IDevID and MAY
possess the site-specific domain CA certificate.
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+-----------+ +-----------+ +--------+ +---------+
| Registrar-| | Domain | | Domain | | Vendor |
| Agent | | Registrar | | CA | | Service |
| (RegAgt) | | (JRC) | | | | (MASA) |
+-----------+ +-----------+ +--------+ +---------+
| | | Internet |
[voucher + enrollment] | | |
[PVR, PER available ] | | |
| | | |
|<----- mTLS ------>| | |
| [Reg-Agt authenticated | |
| and authorized?] | |
| | | |
|--- Voucher-Req -->| | |
| (PVR) | | |
| [Reg-Agt authorized?] | |
| [accept device?] | |
| [contact vendor] |
| |------------- mTLS ----------->|
| |--------- Voucher-Req -------->|
| | (RVR) |
| | [extract DomainID]
| | [update audit log]
| |<---------- Voucher -----------|
|<---- Voucher -----| | |
| | | |
|--- Enroll-Req --->| | |
| (PER) | | |
| |<----- mTLS ----->| |
| |--- Enroll-Req -->| |
| | (RER) | |
| |<-- Enroll-Resp---| |
|<-- Enroll-Resp ---| | |
| | | |
|--- caCerts-Req -->| | |
|<-- caCerts-Res ---| | |
| | | |
Figure 11: Request processing between Registrar-Agent and
bootstrapping services
The Registrar-Agent establishes a TLS connection to the registrar.
As already stated in [RFC8995], the use of TLS 1.3 (or newer) is
encouraged. TLS 1.2 or newer is REQUIRED on the Registrar-Agent
side. TLS 1.3 (or newer) SHOULD be available on the registrar, but
TLS 1.2 MAY be used. TLS 1.3 (or newer) SHOULD be available on the
MASA, but TLS 1.2 MAY be used.
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6.2.1. Connection Establishment (Registrar-Agent to Registrar)
In contrast to BRSKI [RFC8995] TLS client authentication to the
registrar is achieved by using Registrar-Agent EE credentials instead
of pledge IDevID credentials. Consequently BRSKI (pledge-initiator-
mode) is distinguishable from BRSKI-PRM (pledge-responder-mode) by
the registrar. The registrar SHOULD verify that the Registrar-Agent
is authorized to establish a connection to the registrar based on the
TLS client authentication. If the connection from Registrar-Agent to
registrar is established, the authorization SHOULD be verified again
based on agent-signed-data contained in the PVR. This ensures that
the pledge has been triggered by an authorized Registrar-Agent.
With BRSKI-PRM, the pledge generates PVR and PER as JSON-in-JWS
objects and the Registrar-Agent forwards them to the registrar. In
[RFC8995], the pledge generates PVR as CMS-signed JSON and PER as
PKCS#10 or PKCS#7 according to [RFC7030] and inherited by [RFC8995].
For BRSKI-PRM, the Registrar-Agent sends the PVR by HTTP POST to the
same registrar endpoint as introduced by BRSKI: "/.well- known/brski/
requestvoucher", but with a Content-Type header field for JSON-in-
JWS"
The Content-Type header field for JSON-in-JWS PVR is: application/
voucher-jws+json (see Figure 8 for the content definition), as
defined in [I-D.ietf-anima-jws-voucher].
The Registrar-Agent sets the Accept field in the request-header
indicating the acceptable Content-Type for the voucher-response. The
voucher-response Content-Type header field is set to application/
voucher-jws+json as defined in [I-D.ietf-anima-jws-voucher].
6.2.2. Pledge-Voucher-Request (PVR) Processing by Registrar
After receiving the PVR from Registrar-Agent, the registrar SHALL
perform the verification as defined in section 5.3 of [RFC8995]. In
addition, the registrar SHALL verify the following parameters from
the PVR:
* agent-provided-proximity-registrar-cert: MUST contain registrar's
own registrar LDevID certificate to ensure the registrar in
proximity of the Registrar-Agent is the desired registrar for this
PVR.
* agent-signed-data: The registrar MUST verify that the Registrar-
Agent provided data has been signed with the private key
corresponding to the EE (RegAgt) certificate indicated in the
"kid" JOSE header parameter. The registrar MUST verify that the
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LDevID(ReAgt) certificate, corresponding to the signature, is
still valid. If the certificate is already expired, the registrar
SHALL reject the request. Validity of used signing certificates
at the time of signing the agent-signed-data is necessary to avoid
that a rogue Registrar-Agent generates agent-signed-data objects
to onboard arbitrary pledges at a later point in time, see also
Section 10.3. The registrar MUST fetch the EE (RegAgt)
certificate, based on the provided SubjectKeyIdentifier (SKID)
contained in the "kid" header parameter of the agent-signed-data,
and perform this verification. This requires, that the registrar
has access to the EE (RegAgt) certificate data (including
intermediate CA certificates if existent) based on the SKID.
Note, the registrar may have stored the EE (RegAgt) certificate if
used during TLS establishment between Registrar-Agent and
registrar or it may be provided via a repository.
If the registrar is unable to validate the PVR it SHOULD respond with
a HTTP 4xx/5xx error code to the Registrar-Agent.
The following 4xx client error codes SHOULD be used:
* 403 Forbidden: if the registrar detected that one or more security
related parameters are not valid.
* 404 Not Found status code if the pledge provided information could
not be used with automated allowance, as described in section 5.3
of [RFC8995].
* 406 Not Acceptable: if the Content-Type indicated by the Accept
header is unknown or unsupported.
If the validation succeeds, the registrar performs pledge
authorization according to [RFC8995], Section 5.3 followed by
obtaining a voucher from the pledge's MASA according to [RFC8995],
Section 5.4 with the modifications described below in Section 6.2.3.
6.2.3. Registrar-Voucher-Request (RVR) Processing (Registrar to MASA)
If the MASA address/URI is learned from the [RFC8995] Section 2.3
IDevID MASA URI extension, then the MASA on that URI MUST support the
procedures defined in this document if the PVR used JSON-JWS
encoding. If the MASA is only configured on the registrar, then a
registrar supporting BRKSI-PRM and other voucher encoding formats
(such as those in [RFC8995]) SHOULD support per-message-format MASA
address/URI configuration for the same IDevID trust anchor."
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The registrar SHALL construct the payload of the RVR as defined in
[RFC8995], Section 5.5. The RVR encoding SHALL be JSON-in-JWS as
defined in [I-D.ietf-anima-jws-voucher].
The header of the RVR SHALL contain the following parameter as
defined for JWS [RFC7515]:
* alg: algorithm used to create the object signature
* x5c: base64-encoded registrar LDevID certificate(s) (It optionally
contains the certificate chain for this certificate)
The payload of the RVR MUST contain the following parameter as part
of the voucher-request as defined in [RFC8995]:
* created-on: current date and time in yang:date-and-time format of
RVR creation
* nonce: copied from the PVR
* serial-number: product-serial-number of pledge. The registrar
MUST verify that the IDevID certificate subject serialNumber of
the pledge (X520SerialNumber) matches the serial-number value in
the PVR. In addition, it MUST be equal to the serial-number value
contained in the agent-signed data of PVR.
* assertion: voucher assertion requested by the pledge (agent-
proximity). The registrar provides this information to assure
successful verification of Registrar-Agent proximity based on the
agent-signed-data.
* prior-signed-voucher-request: PVR as received from Registrar-
Agent, see Section 6.1.2
The RVR MUST be extended with the following parameter, when the
assertion "agent-proximity" is requested, as defined in
[I-D.ietf-anima-rfc8366bis]:
* agent-sign-cert: EE (RegAgt) certificate or the EE (RegAgt)
certificate including certificate chain. In the context of this
document it is a JSON array of base64encoded certificate
information and handled in the same way as x5c header objects. If
only a single object is contained in the x5c it MUST be the
base64-encoded EE (RegAgt) certificate. If multiple certificates
are included in the x5c, the first MUST be the base64-encoded EE
(RegAgt) certificate.
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The MASA uses this information for verification that the Registrar-
Agent is in proximity to the registrar to state the corresponding
assertion "agent-proximity".
The object is signed using the registrar LDevID credentials, which
corresponds to the certificate referenced in the JOSE header.
# The RVR in General JWS Serialization syntax
{
"payload": "BASE64URL(ietf-voucher-request-prm:voucher)",
"signatures": [
{
"protected": "BASE64URL(UTF8(JWS Protected Header))",
"signature": BASE64URL(JWS Signature)
}
]
}
# Example: Decoded payload "ietf-voucher-request-prm:voucher"
representation in JSON syntax
"ietf-voucher-request-prm:voucher": {
"created-on": "2022-01-04T02:37:39.235Z",
"nonce": "eDs++/FuDHGUnRxN3E14CQ==",
"serial-number": "callee4711",
"assertion": "agent-proximity",
"prior-signed-voucher-request": "base64encodedvalue==",
"agent-sign-cert": [
"base64encodedvalue==",
"base64encodedvalue==",
"..."
]
}
# Example: Decoded "JWS Protected Header" representation
in JSON syntax
{
"alg": "ES256",
"x5c": [
"base64encodedvalue==",
"base64encodedvalue=="
],
"typ": "voucher-jws+json"
}
Figure 12: Representation of RVR
The registrar SHALL send the RVR to the MASA endpoint by HTTP POST:
"/.well-known/brski/requestvoucher"
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The RVR Content-Type header field is defined in
[I-D.ietf-anima-jws-voucher] as: application/voucher-jws+json
The registrar SHOULD set the Accept header of the RVR indicating the
desired media type for the voucher-response. The media type is
application/voucher-jws+json as defined in
[I-D.ietf-anima-jws-voucher].
This document uses the JSON-in-JWS format throughout the definition
of exchanges and in the examples. Nevertheless, alternative
encodings of the voucher as used in BRSKI [RFC8995] with JSON-in-CMS
or CBOR-in-COSE_Sign [RFC8152] for constraint environments are
possible as well. The assumption is that a pledge typically supports
a single encoding variant and creates the PVR in the supported
format. To ensure that the pledge is able to process the voucher,
the registrar MUST use the media type for Accept header in the RVR
based on the media type used for the PVR.
Once the MASA receives the RVR it SHALL perform the verification as
described in Section 5.5 in [RFC8995].
In addition, the following processing SHALL be performed for PVR
contained in RVR "prior-signed-voucher-request" field:
* agent-provided-proximity-registrar-cert: The MASA MAY verify that
this field contains the registrar LDevID certificate. If so, it
MUST correspond to the registrar LDevID credentials used to sign
the RVR. Note: Correspond here relates to the case that a single
registrar LDevID certificate is used or that different registrar
LDevID certificates are used, which are issued by the same CA.
* agent-signed-data: The MASA MAY verify this data to issue "agent-
proximity" assertion. If so, the agent-signed-data MUST contain
the pledge product-serial-number, contained in the "serial-number"
field of the PVR (from "prior-signed-voucher-request" field) and
also in "serial-number" field of the RVR. The EE (RegAgt)
certificate to be used for signature verification is identified by
the "kid" parameter of the JOSE header. If the assertion "agent-
proximity" is requested, the RVR MUST contain the corresponding EE
(RegAgt) certificate data in the "agent-sign-cert" field of the
RVR. It MUST be verified by the MASA to the same domain CA as the
registrar LDevID certificate. If the "agent-sign-cert" field is
not set, the MASA MAY state a lower level assertion value, e.g.:
"logged" or "verified". Note: Sub-CA certificate(s) MUST also be
carried by "agent-sign-cert", in case the EE (RegAgt) certificate
is issued by a sub-CA and not the domain CA known to the MASA. As
the "agent-sign-cert" field is defined as array (x5c), it can
handle multiple certificates.
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If validation fails, the MASA SHOULD respond with an HTTP 4xx client
error status code to the registrar. The HTTP error status codes are
kept the same as defined in Section 5.6 of [RFC8995] and comprise the
codes: 403, 404, 406, and 415.
6.2.4. Voucher Issuance by MASA
The MASA creates a voucher with Media-Type of application/voucher-
jws+json as defined in [I-D.ietf-anima-jws-voucher]. If the MASA
detects that the Accept header of the PVR does not match application/
voucher-jws+json it SHOULD respond with the HTTP status code "406 Not
Acceptable" as the pledge will not be able to parse the response.
The voucher is according to [I-D.ietf-anima-rfc8366bis] but uses the
new assertion value specified Section 5.4.
Figure 13 shows an example of the contents of a voucher.
# The MASA issued voucher in General JWS Serialization syntax
{
"payload": "BASE64URL(ietf-voucher:voucher)",
"signatures": [
{
"protected": "BASE64URL(UTF8(JWS Protected Header))",
"signature": BASE64URL(JWS Signature)
}
]
}
# Example: Decoded payload "ietf-voucher:voucher" representation
in JSON syntax
"ietf-voucher:voucher": {
"assertion": "agent-proximity",
"serial-number": "callee4711",
"nonce": "base64encodedvalue==",
"created-on": "2022-01-04T00:00:02.000Z",
"pinned-domain-cert": "base64encodedvalue=="
}
# Example: Decoded "JWS Protected Header" representation
in JSON syntax
{
"alg": "ES256",
"x5c": [
"base64encodedvalue==",
"base64encodedvalue=="
],
"typ": "voucher-jws+json"
}
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Figure 13: Representation of MASA issued voucher
The pinned-domain certificate to be put into the voucher is
determined by the MASA as described in section 5.5 of [RFC8995]. The
MASA returns the voucher-response (voucher) to the registrar.
6.2.5. MASA issued Voucher Processing by Registrar
After receiving the voucher the registrar SHOULD evaluate it for
transparency and logging purposes as outlined in Section 5.6 of
[RFC8995]. The registrar MUST add an additional signature to the
MASA provided voucher using its registrar EE credentials.
The signature is created by signing the original "JWS Payload"
produced by MASA and the registrar added "JWS Protected Header" using
the registrar EE credentials (see [RFC7515], Section 5.2 point 8.
The x5c component of the "JWS Protected Header" MUST contain the
registrar EE certificate as well as potential subordinate CA
certificates up to (but not including) the pinned domain certificate.
The pinned domain certificate is already contained in the voucher
payload ("pinned-domain-cert").
(For many installations, with a single registrar credential, the
registrar credential is what is pinned)
In [RFC8995], the Registrar proved possession of the it's credential
when the TLS session was setup. While the pledge could not, at the
time, validate the certificate truly belonged the registrar, it did
validate that the certificate it was provided was able to
authenticate the TLS connection.
In the BRSKI-PRM mode, with the Registrar-Agent mediating all
communication, the Pledge has not as yet been able to witness that
the intended Registrar really does possess the relevant private key.
This second signature provides for the same level of assurance to the
pledge, and that it matches the public key that the pledge received
in the trigger for the PVR (see Figure 6).
The registrar MUST use the same registrar EE credentials used for
authentication in the TLS handshake to authenticate towards the
Registrar-Agent. This has some operational implications when the
registrar may be part of a scalable framework as described in
[I-D.richardson-anima-registrar-considerations], Section 1.3.1.
The second signature MUST either be done with the private key
associated with the registrar EE certificate provided to the
Registrar-Agent, or the use of a certificate chain is necessary.
This ensures that the same registrar EE certificate can be used to
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verify the signature as transmitted in the voucher-request as also
transferred in the PVR in the "agent-provided-proximity-registrar-
cert".
Figure 14 below provides an example of the voucher with two
signatures.
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# The MASA issued voucher with additional registrar signature in
General JWS Serialization syntax
{
"payload": "BASE64URL(ietf-voucher:voucher)",
"signatures": [
{
"protected": "BASE64URL(UTF8(JWS Protected Header (MASA)))",
"signature": BASE64URL(JWS Signature)
},
{
"protected": "BASE64URL(UTF8(JWS Protected Header (Reg)))",
"signature": BASE64URL(JWS Signature)
}
]
}
# Example: Decoded payload "ietf-voucher:voucher" representation in
JSON syntax
"ietf-voucher:voucher": {
"assertion": "agent-proximity",
"serial-number": "callee4711",
"nonce": "base64encodedvalue==",
"created-on": "2022-01-04T00:00:02.000Z",
"pinned-domain-cert": "base64encodedvalue=="
}
# Example: Decoded "JWS Protected Header (MASA)" representation
in JSON syntax
{
"alg": "ES256",
"x5c": [
"base64encodedvalue==",
"base64encodedvalue=="
],
"typ": "voucher-jws+json"
}
# Example: Decoded "JWS Protected Header (Reg)" representation
in JSON syntax
{
"alg": "ES256",
"x5c": [
"base64encodedvalue==",
"base64encodedvalue=="
]
}
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Figure 14: Representation of MASA issued voucher with additional
registrar signature
Depending on the security policy of the operator, this signature can
also be interpreted by the pledge as explicit authorization of the
registrar to install the contained trust anchor. The registrar sends
the voucher to the Registrar-Agent.
6.2.6. Pledge-Enrollment-Request (PER) Processing (Registrar-Agent to
Registrar)
After receiving the voucher, the Registrar-Agent sends the PER to the
registrar in the same HTTP-over-TLS connection. Which is similar to
the PER processing described in Section 5.2 of [RFC8995]. In case
the PER cannot be send in the same HTTP-over-TLS connection the
Registrar-Agent may send the PER in a new HTTP-over-TLS connection.
The registrar is able to correlate the PVR and the PER based on the
signatures and the contained product-serial-number information.
Note, this also addresses situations in which a nonceless voucher is
used and may be pre-provisioned to the pledge. As specified in
Section 6.1.4 deviating from BRSKI the PER is not a raw PKCS#10. As
the Registrar-Agent is involved in the exchange, the PKCS#10 is
wrapped in a JWS object by the pledge and signed with pledge's IDevID
to ensure proof-of-identity as outlined in Figure 10.
EST [RFC7030] standard endpoints (/simpleenroll, /simplereenroll,
/serverkeygen, /cacerts) on the registrar cannot be used for BRSKI-
PRM. This is caused by the utilization of signature wrapped-objects
in BRSKI-PRM. As EST requires to sent a raw PKCS#10 request to e.g.,
"/.well-known/est/simpleenroll" endpoint, this document makes an
enhancement by utilizing EST but with the exception to transport a
signature wrapped PKCS#10 request. Therefore a new endpoint for
BRSKI-PRM on the registrar is defined as "/.well-known/brski/
requestenroll"
The Content-Type header of PER is: application/jose+json.
This is a deviation from the Content-Type header values used in
[RFC7030] and results in additional processing at the domain
registrar (as EST server). Note, the registrar is already aware that
the bootstrapping is performed in a pledge-responder-mode due to the
use of the EE (RegAgt) certificate for TLS and the provided PVR as
JSON-in-JWS object.
* If the registrar receives a PER with Content-Type header:
application/jose+json, it MUST verify the wrapping signature using
the certificate indicated in the JOSE header.
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* The registrar verifies that the pledge's certificate (here
IDevID), carried in "x5c" header field, is accepted to join the
domain after successful validation of the PVR.
* If both succeed, the registrar utilizes the PKCS#10 request
contained in the JWS object body as "P10" parameter of "ietf-sztp-
csr:csr" for further processing of the enrollment-request with the
corresponding domain CA. It creates a registrar enrollment-
request (RER) by utilizing the protocol expected by the domain CA.
The domain registrar may either directly forward the provided
PKCS#10 request to the CA or provide additional information about
attributes to be included by the CA into the requested LDevID
certificate. The approach of sending this information to the CA
depends on the utilized certificate management protocol between
the RA and the CA and is out of scope for this document.
Note while BRSKI-PRM targets the initial enrollment, re-enrollment
may be supported in a similar way with the exception that the current
LDevID certificate is used instead of the IDevID certificate to
verify the wrapping signature of the PKCS#10 request (see also
Section 6.1.4).
The Registrar-Agent SHALL send the PER to the registrar by HTTP POST
to the endpoint: "/.well-known/brski/requestenroll"
The registrar SHOULD respond with an HTTP 200 OK in the success case
or fail with HTTP 4xx/5xx status codes as defined by the HTTP
standard.
A successful interaction with the domain CA will result in a pledge
LDevID certificate, which is then forwarded by the registrar to the
Registrar-Agent using the Content-Type header: application/
pkcs7-mime.
6.2.7. Request Wrapped-CA-certificate(s) (Registrar-Agent to Registrar)
As the pledge will verify it own certificate LDevID certificate when
received, it also needs the corresponding CA certificates. This is
done in EST [RFC7030] using the "/.well-known/est/cacerts" endpoint,
which provides the CA certificates over a TLS protected connection.
BRSKI-PRM requires a signature wrapped CA certificate object, to
avoid that the pledge can be provided with arbitrary CA certificates
in an authorized way. The registrar signed CA certificate object
will allow the pledge to verify the authorization to install the
received CA certificate(s). As the CA certificate(s) are provided to
the pledge after the voucher, the pledge has the required information
(the domain certificate) to verify the wrapped CA certificate object.
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To support Registrar-Agents requesting a signature wrapped CA
certificate(s) object, a new endpoint for BRSKI-PRM is defined on the
registrar: "/.well-known/brski/wrappedcacerts"
The Registrar-Agent SHALL requests the EST CA trust anchor database
information (in form of CA certificates) by HTTP GET.
The Content-Type header of the response SHALL be: application/
jose+json.
This is a deviation from the Content-Type header values used in EST
[RFC7030] and results in additional processing at the domain
registrar (as EST server). The additional processing is to sign the
CA certificate(s) information using the registrar LDevID credentials.
This results in a signed CA certificate(s) object (JSON-in-JWS), the
CA certificates are provided as base64 encoded "x5bag" (see
definition in [RFC9360]) in the JWS payload.
# The CA certificates data with registrar signature in General JWS Serialization syntax
{
"payload": "BASE64URL(certs)",
"signatures": [
{
"protected": "BASE64URL(UTF8(JWS Protected Header))",
"signature": BASE64URL(JWS Signature)
}
]
}
# Example: Decoded payload "certs" representation in JSON syntax
{
"x5bag": [
"base64encodedvalue==",
"base64encodedvalue=="
]
}
# Example: Decoded "JWS Protected Header" representation
in JSON syntax
{
"alg": "ES256",
"x5c": [
"base64encodedvalue==",
"base64encodedvalue=="
]
}
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Figure 15: Representation of CA certificate(s) data with
registrar signature
6.3. Response Objects supplied by the Registrar-Agent to the Pledge
It is assumed that the Registrar-Agent already obtained the
bootstrapping response objects from the domain registrar and can
supply them to the pledge:
* voucher-response - Voucher (from MASA via Registrar)
* wrapped-CA-certificate(s)-response - CA certificates
* enrollment-response - LDevID (Pledge) certificate (from CA via
registrar)
To deliver these response objects, the Registrar-Agent will re-
connect to the pledge. To contact the pledge, it may either discover
the pledge as described in Section 5.6.2 or use stored information
from the first contact with the pledge.
Preconditions in addition to Section 6.2:
* Registrar-Agent: obtained voucher and LDevID certificate and
optionally IDevID CA certificates. The IDevID CA certificate is
necessary, when the connection between the Registrar-Agent and the
pledge is established using TLS to enable the Registrar-Agent to
validate the pledges' IDevID certificate during the TLS handshake
as described in Section 6.1.
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+--------+ +-----------+
| Pledge | | Registrar-|
| | | Agent |
| | | (RegAgt) |
+--------+ +-----------+
| [voucher and enrollment]
| [responses available]
| |
|<----- optional TLS connection ----|
| |
|<------- supply voucher -----------|
| |
|--------- voucher status --------->| - store
| | pledge voucher status
|<--- supply CAcerts (optional) ----|
| |
|<--- supply enrollment-response ---|
| |
|--------- enroll status ---------->| - store
| | pledge enroll status
Figure 16: Responses and status handling between pledge and
Registrar-Agent
The Registrar-Agent MAY optionally use TLS to protect the
communication as outlined in Section 6.1.
The Registrar-Agent provides the information via distinct pledge
endpoints as following.
6.3.1. Pledge: Voucher-Response Processing
The Registrar-Agent SHALL send the voucher-response to the pledge by
HTTP POST to the endpoint: "/.well-known/brski/svr".
The Registrar-Agent voucher-response Content-Type header is
application/voucher-jws+json and contains the voucher as provided by
the MASA. An example is given in Figure 13 for a MASA signed voucher
and in Figure 14 for the voucher with the additional signature of the
registrar.
A nonceless voucher may be accepted as in [RFC8995] and may be
allowed by a manufacture's pledge implementation.
To perform the validation of several signatures on the voucher
object, the pledge SHALL perform the signature verification in the
following order:
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1. Verify MASA signature as described in Section 5.6.1 in [RFC8995],
against pre-installed manufacturer trust anchor (IDevID).
2. Install trust anchor contained in the voucher ("pinned-domain-
cert") provisionally
3. Validate the LDevID(Reg) certificate received in the agent-
provided-proximity-registrar-cert in the pledge-voucher-request
trigger request (in the field "agent-provided-proximity-
registrar-cert")
4. Verify registrar signature of the voucher similar as described in
Section 5.6.1 in [RFC8995], but take the registrar certificate
instead of the MASA certificate for the verification
Step3 and step 4 have been introduced in BRSKI-PRM to enable
verification of LDevID(Reg) certificate and also the proof-of-
possession of the corresponding private key by the registrar, which
is done in BRSKI based on the established TLS channel. If all steps
stated above have been performed successfully, the pledge SHALL
terminate the "PROVISIONAL accept" state for the domain trust anchor
and the registrar LDevID certificate.
If an error occurs during the verification and validation of the
voucher, this SHALL be reported in the reason field of the pledge
voucher status.
6.3.2. Pledge: Voucher Status Telemetry
After voucher verification and validation the pledge MUST reply with
a status telemetry message as defined in Section 5.7 of [RFC8995].
The pledge generates the voucher-status and provides it as signed
JSON-in-JWS object in response to the Registrar-Agent.
The response has the Content-Type application/jose+json and is signed
using the IDevID of the pledge as shown in Figure 17. As the reason
field is optional (see [RFC8995]), it MAY be omitted in case of
success.
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# The "pledge-voucher-status" telemetry in general JWS
serialization syntax
{
"payload": "BASE64URL(pledge-voucher-status)",
"signatures": [
{
"protected": "BASE64URL(UTF8(JWS Protected Header))",
"signature": BASE64URL(JWS Signature)
}
]
}
# Example: Decoded payload "pledge-voucher-status" representation
in JSON syntax for success case
{
"version": 1,
"status": true,
"reason": "Voucher successfully processed",
"reason-context": {
"pvs-details": "JSON"
}
}
# Example: Decoded payload "pledge-voucher-status" representation
in JSON syntax for error case
{
"version": 1,
"status": false,
"reason": "Failed to authenticate MASA certificate because
it starts in the future (1/1/2023).",
"reason-context": {
"pvs-details": "Current date: 1/1/1970"
}
}
# Example: Decoded "JWS Protected Header" representation
in JSON syntax
{
"alg": "ES256",
"x5c": [
"base64encodedvalue==",
"base64encodedvalue=="
]
}
Figure 17: Representation of pledge voucher status telemetry
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If the pledge did not did not provide voucher status telemetry
information after processing the voucher, the Registrar-Agent MAY
query the pledge status explicitly as described in Section 6.4 and
MAY resent the voucher depending on the Pledge status following the
procedure described in Section 6.3.1.
6.3.3. Pledge: Wrapped-CA-Certificate(s) Processing
The Registrar-Agent SHALL provide the set of CA certificates
requested from the registrar to the pledge by HTTP POST to the
endpoint: "/.well-known/brski/scac".
As the CA certificate provisioning is crucial from a security
perspective, this provisioning SHOULD only be done, if the voucher-
response has been successfully processed by pledge as reflected in
the voucher status telemetry.
The CA certificates message has the Content-Type application/
jose+json and is signed using the credential of the registrar as
shown in Figure 15.
The CA certificates are provided as base64 encoded "x5bag". The
pledge SHALL install the received CA certificates as trust anchor
after successful verification of the registrar's signature.
The verification comprises the following steps the pledge MUST
perform. Maintaining the order of versification steps as indicated
allows to determine, which verification has already been passed:
1. Check content-type of the CA certificates message. If no
Content-Type is contained in the HTTP header, the default
Content-Type utilized in this document (JSON-in-JWS) is used. If
the Content-Type of the response is in an unknown or unsupported
format, the pledge SHOULD reply with a 415 Unsupported media type
error code.
2. Check the encoding of the payload. If the pledge detects errors
in the encoding of the payload, it SHOULD reply with 400 Bad
Request error code.
3. Verify that the wrapped CA certificate object is signed using the
registrar certificate against the pinned-domain certificate.
This MAY be done by comparing the hash that is indicating the
certificate used to sign the message is that of the pinned-domain
certificate. If the validation against the pinned domain-
certificate fails, the client SHOULD reply with a 401
Unauthorized error code. It signals that the authentication has
failed and therefore the object was not accepted.
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4. Verify signature of the the received wrapped CA certificate
object. If the validation of the signature fails, the pledge
SHOULD reply with a 406 Not Acceptable. It signals that the
object has not been accepted.
5. If the received CA certificates are not self-signed, i.e., an
intermediate CA certificate, verify them against an already
installed trust anchor, as described in section 4.1.3 of
[RFC7030].
6.3.4. Pledge: Enrollment-Response Processing
The Registrar-Agent SHALL send the enroll-response to the pledge by
HTTP POST to the endpoint: "/.well-known/brski/ser".
The Registrar-Agent enroll-response Content-Type header, when using
EST [RFC7030] as enrollment protocol between the Registrar-Agent and
the infrastructure is: application/pkcs7-mime. Note: It only
contains the LDevID certificate for the pledge, not the certificate
chain.
Upon reception, the pledge SHALL verify the received LDevID
certificate. The pledge SHALL generate the enroll status and provide
it in the response to the Registrar-Agent. If the verification of
the LDevID certificate succeeds, the status property SHALL be set to
"status": true, otherwise to "status": false
6.3.5. Pledge: Enrollment-Status Telemetry
The pledge MUST reply with a status telemetry message as defined in
Section 5.9.4 of [RFC8995]. As for the other objects, the enroll-
status is signed and results in a JSON-in-JWS object. If the pledge
verified the received LDevID certificate successfully it SHALL sign
the response using its new LDevID credentials as shown in Figure 18.
In the failure case, the pledge SHALL use the available IDevID
credentials. As the reason field is optional, it MAY be omitted in
case of success.
The response has the Content-Type application/jose+json.
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# The "pledge-enroll-status" telemetry in General JWS Serialization
syntax
{
"payload": "BASE64URL(pledge-enroll-status)",
"signatures": [
{
"protected": "BASE64URL(UTF8(JWS Protected Header))",
"signature": BASE64URL(JWS Signature)
}
]
}
# Example: Decoded payload "pledge-enroll-status" representation
in JSON syntax for success case
{
"version": 1,
"status": true,
"reason": "Enrollment response successfully processed",
"reason-context": {
"pes-details": "JSON"
}
}
# Example: Decoded payload "pledge-voucher-status" representation
in JSON syntax for error case
{
"version": 1,
"status": false,
"reason": "Enrollment response could not be verified.",
"reason-context": {
"pes-details": "no matching trust anchor"
}
}
# Example: Decoded "JWS Protected Header" representation
in JSON syntax
{
"alg": "ES256",
"x5c": [
"base64encodedvalue==",
"base64encodedvalue=="
]
}
Figure 18: Representation of pledge enroll status telemetry
Once the Registrar-Agent has collected the information, it can
connect to the registrar to provide it with the status responses.
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6.3.6. Telemetry Voucher Status and Enroll Status Handling (Registrar-
Agent to Domain Registrar)
The following description requires that the Registrar-Agent has
collected the status information from the pledge. It SHALL provide
the status information to the registrar for further processing.
Preconditions in addition to Section 6.2:
* Registrar-Agent: obtained voucher status and enroll status from
pledge.
+-----------+ +-----------+ +--------+ +---------+
| Registrar-| | Domain | | Domain | | Vendor |
| Agent | | Registrar | | CA | | Service |
| (RegAgt) | | (JRC) | | | | (MASA) |
+-----------+ +-----------+ +--------+ +---------+
| | | Internet |
[voucher + enroll ] | | |
[status info available] | | |
| | | |
|<------- mTLS ------->| | |
| | | |
|--- Voucher Status -->| | |
| |--- req-device audit log-->|
| |<---- device audit log ----|
| [verify audit log ]
| | | |
|--- Enroll Status --->| | |
| | | |
Figure 19: Bootstrapping status handling
The Registrar-Agent MUST provide the collected pledge voucher status
to the registrar. This status indicates if the pledge could process
the voucher successfully or not.
In case the TLS connection to the registrar is already closed, the
Registrar-Agent opens a new TLS connection with the registrar as
stated in Section 6.2.
The Registrar-Agent sends the pledge voucher status without
modification to the registrar with an HTTP-over-TLS POST using the
registrar endpoint "/.well-known/brski/voucher_status". The Content-
Type header is kept as application/jose+json as described in
Figure 16 and depicted in the example in Figure 17.
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The registrar SHOULD log the transaction provided for a pledge via
Registrar-Agent and include the identity of the Registrar-Agent in
these logs. For log analysis the following may be considered:
* The registrar knows the interacting Registrar-Agent from the
authentication of the Registrar-Agent towards the registrar using
LDevID (RegAgt) and can log it accordingly.
* The telemetry information from the pledge can be correlated to the
voucher response provided from the registrar to the Registrar-
Agent and further to the pledge.
* The telemetry information, when provided to the registrar is
provided via the Registrar-Agent and can thus be correlated.
The registrar SHALL verify the signature of the pledge voucher status
and validate that it belongs to an accepted device of the domain
based on the contained "serial-number" in the IDevID certificate
referenced in the header of the voucher status.
According to [RFC8995] Section 5.7, the registrar SHOULD respond with
an HTTP 200 OK in the success case or fail with HTTP 4xx/5xx status
codes as defined by the HTTP standard. The Registrar-Agent may use
the response to signal success / failure to the service technician
operating the Registrar-Agent. Within the server logs the server
SHOULD capture this telemetry information.
The registrar SHOULD proceed with collecting and logging status
information by requesting the MASA audit-log from the MASA service as
described in Section 5.8 of [RFC8995].
The Registrar-Agent MUST provide the pledge's enroll status to the
registrar. The status indicates the pledge could process the enroll-
response (certificate) and holds the corresponding private key.
The Registrar-Agent sends the pledge enroll status without
modification to the registrar with an HTTP-over-TLS POST using the
registrar endpoint "/.well-known/brski/enrollstatus". The Content-
Type header is kept as application/jose+json as described in
Figure 16 and depicted in the example in Figure 18.
The registrar MUST verify the signature of the pledge enroll status.
Also, the registrar SHALL validate that the pledge is an accepted
device of the domain based on the contained product-serial-number in
the LDevID certificate referenced in the header of the enroll status.
The registrar SHOULD log this event. In case the pledge enroll
status indicates a failure, the pledge was unable to verify the
received LDevID certificate and therefore signed the enroll status
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with its IDevID credential. Note that the signature verification of
the status information is an addition to the described handling in
Section 5.9.4 of [RFC8995], and is replacing the pledges TLS client
authentication by DevID credentials in [RFC8995].
According to [RFC8995] Section 5.9.4, the registrar SHOULD respond
with an HTTP 200 OK in the success case or fail with HTTP 4xx/5xx
status codes as defined by the HTTP standard. Based on the failure
case the registrar MAY decide that for security reasons the pledge is
not allowed to reside in the domain. In this case the registrar MUST
revoke the certificate. An example case for the registrar revoking
the issued LDevID for the pledge is when the pledge was not able to
verify the received LDevID certificate and therefore did send a 406
(Not Acceptable) response. In this case the registrar may revoke the
LDevID certificate as the pledge did no accepted it for installation.
The Registrar-Agent may use the response to signal success / failure
to the service technician operating the Registrar-Agent. Within the
server log the registrar SHOULD capture this telemetry information.
6.4. Request Pledge-Status by Registrar-Agent from Pledge
The following assumes that a Registrar-Agent may need to query the
status of a pledge. This information may be useful to solve errors,
when the pledge was not able to connect to the target domain during
the bootstrapping. The pledge MAY provide a dedicated endpoint to
accept status-requests.
Preconditions:
* Registrar-Agent: possesses LDevID (RegAgt), may have a list of
product-serial-number(s) of pledges to be queried and a list of
corresponding manufacturer trust anchors to be able to verify
signatures performed with the IDevID credential.
* Pledge: may already possess domain credentials and LDevID(Pledge),
or may not possess one or both of these.
+--------+ +-----------+
| Pledge | | Registrar-|
| | | Agent |
| | | (RegAgt) |
+--------+ +-----------+
| |
|<--- pledge-status request -----|
| |
|---- pledge-status response --->|
| |
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Figure 20: Pledge-status handling between Registrar-Agent and pledge
6.4.1. Pledge-Status - Request (Registrar-Agent to Pledge)
The Registrar-Agent requests the pledge-status via HTTP POST on the
defined pledge endpoint: "/.well-known/brski/qps"
The Registrar-Agent Content-Type header for the pledge-status request
is: application/jose+json. It contains information on the requested
status-type, the time and date the request is created, and the
product serial-number of the pledge contacted as shown in Figure 21.
The pledge-status request is signed by Registrar-Agent using the
private key corresponding to the EE (RegAgt) certificate.
The following Concise Data Definition Language (CDDL) [RFC8610]
explains the structure of the format for the pledge-status request.
It is defined following the status telemetry definitions in BRSKI
[RFC8995]. Consequently, format and semantics of pledge-status
requests below are for version 1. The version field is included to
permit significant changes to the pledge-status request and response
in the future. A pledge or a Registrar-Agent that receives a pledge-
status request with a version larger than it knows about SHOULD log
the contents and alert a human.
<CODE BEGINS>
status-request = {
"version": uint,
"created-on": tdate ttime,
"serial-number": text,
"status-type": text
}
<CODE ENDS>
Figure 21: CDDL for pledge-status request
The status-type defined for BRSKI-PRM is "bootstrap". This indicates
the pledge to provide current status information regarding the
bootstrapping status (voucher processing and enrollment of the pledge
into the new domain). As the pledge-status request is defined
generic, it may be used by other specifications to request further
status information, e.g., for onboarding to get further information
about enrollment of application specific LDevIDs or other parameters.
This is out of scope for this specification.
Figure 22 below shows an example for querying pledge-status using
status-type bootstrap.
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# The Registrar-Agent request of "pledge-status" in general JWS
serialization syntax
{
"payload": "BASE64URL(status-request)",
"signatures": [
{
"protected": "BASE64URL(UTF8(JWS Protected Header))",
"signature": BASE64URL(JWS Signature)
}
]
}
# Example: Decoded payload "status-request" representation
in JSON syntax
{
"version": 1,
"created-on": "2022-08-12T02:37:39.235Z",
"serial-number": "pledge-callee4711",
"status-type": "bootstrap"
}
# Example: Decoded "JWS Protected Header" representation
in JSON syntax
{
"alg": "ES256",
"x5c": [
"base64encodedvalue==",
"base64encodedvalue=="
]
}
Figure 22: Example of Registrar-Agent request of pledge-status
using status-type bootstrap
6.4.2. Pledge-Status - Response (Pledge - Registrar-Agent)
If the pledge receives the pledge-status request with status-type
"bootstrap" it SHALL react with a status response message based on
the telemetry information described in Section 6.3.
The pledge-status response Content-Type header is application/
jose+json.
The following CDDL explains the structure of the format for the
status response, which is:
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<CODE BEGINS>
status-response = {
"version": uint,
"status":
"factory-default" /
"voucher-success" /
"voucher-error" /
"enroll-success" /
"enroll-error" /
"connect-success" /
"connect-error",
?"reason" : text,
?"reason-context": { $$arbitrary-map }
}
<CODE ENDS>
Figure 23: CDDL for pledge-status response
Different cases for pledge bootstrapping status may occur, which
SHOULD be reflected using the status enumeration. This document
specifies the status values in the context of the bootstrapping
process and credential application. Other documents may enhance the
above enumeration to reflect further status information.
The pledge-status response message is signed with IDevID or LDevID,
depending on bootstrapping state of the pledge.
* "factory-default": Pledge has not been bootstrapped. Additional
information may be provided in the reason or reason-context. The
pledge signs the response message using its IDevID(Pledge).
* "voucher-success": Pledge processed the voucher exchange
successfully. Additional information may be provided in the
reason or reason-context. The pledge signs the response message
using its IDevID(Pledge).
* "voucher-error": Pledge voucher processing terminated with error.
Additional information may be provided in the reason or reason-
context. The pledge signs the response message using its
IDevID(Pledge).
* "enroll-success": Pledge has processed the enrollment exchange
successfully. Additional information may be provided in the
reason or reason-context. The pledge signs the response message
using its LDevID(Pledge).
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* "enroll-error": Pledge enrollment-response processing terminated
with error. Additional information may be provided in the reason
or reason-context. The pledge signs the response message using
its IDevID(Pledge).
The reason and the reason-context SHOULD contain the telemetry
information as described in Section 6.3.
As the pledge is assumed to utilize its bootstrapped credentials
(LDevID) in communication with other peers, additional status
information is provided for the connectivity to other peers, which
may be helpful in analyzing potential error cases.
* "connect-success": Pledge could successfully establish a
connection to another peer. Additional information may be
provided in the reason or reason-context. The pledge signs the
response message using its LDevID(Pledge).
* "connect-error": Pledge connection establishment terminated with
error. Additional information may be provided in the reason or
reason-context. The pledge signs the response message using its
LDevID(Pledge).
The pledge-status responses are cumulative in the sense that connect-
success implies enroll-success, which in turn implies voucher-
success.
Figure 24 provides an example for the bootstrapping-status
information.
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# The pledge "status-response" in General JWS Serialization syntax
{
"payload": "BASE64URL(status-response)",
"signatures": [
{
"protected": "BASE64URL(UTF8(JWS Protected Header))",
"signature": BASE64URL(JWS Signature)
}
]
}
# Example: Decoded payload "status-response" representation
in JSON syntax
{
"version": 1,
"status": "enroll-success",
"reason-context": {
"additional" : "JSON"
}
}
# Example: Decoded "JWS Protected Header" representation
in JSON syntax
{
"alg": "ES256",
"x5c": [
"base64encodedvalue==",
"base64encodedvalue=="
],
"typ": "jose+json
}
Figure 24: Example of pledge-status response
* In case "factory-default" the pledge does not possess the domain
certificate resp. the domain trust-anchor. It will not be able to
verify the signature of the Registrar-Agent in the bootstrapping-
status request.
* In cases "vouchered" and "enrolled" the pledge already possesses
the domain certificate (has domain trust-anchor) and can therefore
validate the signature of the Registrar-Agent. If validation of
the JWS signature fails, the pledge SHOULD respond with the HTTP
403 Forbidden status code.
* The HTTP 406 Not Acceptable status code SHOULD be used, if the
Accept header in the request indicates an unknown or unsupported
format.
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* The HTTP 415 Unsupported Media Type status code SHOULD be used, if
the Content-Type of the request is an unknown or unsupported
format.
* The HTTP 400 Bad Request status code SHOULD be used, if the
Accept/Content-Type headers are correct but nevertheless the
status-request cannot be correctly parsed.
The pledge SHOULD by default only respond to requests from nodes it
can authenticate (such as registrar agent), once the pledge is
enrolled with CA certificates and a matching domain certificate.
7. Artifacts
7.1. Voucher-Request Artifact
[I-D.ietf-anima-rfc8366bis] extends the voucher-request as defined in
[RFC8995] to include additional fields necessary for handling
bootstrapping in the pledge-responder-mode. These additional fields
are defined in Section 6.1 as:
* agent-signed-data to provide a JSON encoded artifact from the
involved Registrar-Agent, which allows the registrar to verify the
Registrar-Agent's involvement
* agent-provided-proximity-registrar-cert to provide the registrar
certificate visible to the Registrar-Agent, comparable to the
registrar-proximity-certificate used in [RFC8995]
* agent-signing certificate to optionally provide the Registrar-
Agent signing certificate.
Examples for the application of these fields in the context of a PVR
are provided in Section 6.2.
8. IANA Considerations
This document requires the following IANA actions.
8.1. BRSKI .well-known Registry
IANA is requested to enhance the Registry entitled: "BRSKI Well-Known
URIs" with the following endpoints:
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URI Description Reference
tpvr create pledge voucher-request [THISRFC]
tper create pledge enrollment-request [THISRFC]
svr supply voucher-response [THISRFC]
ser supply enrollment-response [THISRFC]
scac supply CA certificates to pledge [THISRFC]
qps query pledge status [THISRFC]
requestenroll supply PER to registrar [THISRFC]
wrappedcacerts request wrapped CA certificates [THISRFC]
8.2. DNS Service Names
IANA has registered the following service names:
*Service Name:* brski-pledge
*Transport Protocol(s):* tcp
*Assignee:* IESG iesg@ietf.org (mailto:iesg@ietf.org)
*Contact:* IESG iesg@ietf.org (mailto:iesg@ietf.org)
*Description:* The Bootstrapping Remote Secure Key Infrastructure
Pledge
*Reference:* [THISRFC]
9. Privacy Considerations
In general, the privacy considerations of [RFC8995] apply for BRSKI-
PRM also. Further privacy aspects need to be considered for:
* the introduction of the additional component Registrar-Agent
* potentially no transport layer security between Registrar-Agent
and pledge
Section 6.1 describes to optional apply TLS to protect the
communication between the Registrar-Agent and the pledge. The
following is therefore applicable to the communication without the
TLS protection.
The credential used by the Registrar-Agent to sign the data for the
pledge SHOULD NOT contain any personal information. Therefore, it is
recommended to use an LDevID certificate associated with the
commissioning device instead of an LDevID certificate associated with
the service technician operating the device. This avoids revealing
potentially included personal information to Registrar and MASA.
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The communication between the pledge and the Registrar-Agent is
performed over plain HTTP. Therefore, it is subject to disclosure by
a Dolev-Yao attacker (an "oppressive observer")[onpath]. Depending
on the requests and responses, the following information is
disclosed.
* the Pledge product-serial-number is contained in the trigger
message for the PVR and in all responses from the pledge. This
information reveals the identity of the devices being bootstrapped
and allows deduction of which products an operator is using in
their environment. As the communication between the pledge and
the Registrar-Agent may be realized over wireless link, this
information could easily be eavesdropped, if the wireless network
is unencrypted. Even if the wireless network is encrypted, if it
uses a network-wide key, then layer-2 attacks (ARP/ND spoofing)
could insert an on-path observer into the path.
* the Timestamp data could reveal the activation time of the device.
* the Status data of the device could reveal information about the
current state of the device in the domain network.
10. Security Considerations
In general, the security considerations of [RFC8995] apply for BRSKI-
PRM also. Further security aspects are considered here related to:
* the introduction of the additional component Registrar-Agent
* the reversal of the pledge communication direction (push mode,
compared to BRSKI)
* no transport layer security between Registrar-Agent and pledge
10.1. Denial of Service (DoS) Attack on Pledge
Disrupting the pledge behavior by a DoS attack may prevent the
bootstrapping of the pledge to a new domain. Because in BRSKI-PRM,
the pledge responds to requests from real or illicit Registrar-
Agents, pledges are more subject to DoS attacks from Registrar-Agents
in BRSKI-PRM than they are from illicit registrars in [RFC8995],
where pledges do initiate the connections.
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A DoS attack with a faked Registrar-Agent may block the bootstrapping
of the pledge due changing state on the pledge (the pledge may
produce a voucher-request, and refuse to produce another one). One
mitigation may be that the pledge does not limited the number of
voucher-requests it creates until at least one has finished. An
alternative may be that the onboarding state may expire after a
certain time, if no further interaction has happened.
In addition, the pledge may assume that repeated triggering for PVR
are the result of a communication error with the Registrar-Agent. In
that case the pledge MAY simply resent the PVR previously sent. Note
that in case of resending, a contained nonce and also the contained
agent-signed-data in the PVR would consequently be reused.
10.2. Misuse of acquired PVR and PER by Registrar-Agent
A Registrar-Agent that uses previously requested PVR and PER for
domain-A, may attempt to onboard the device into domain-B. This can
be detected by the domain registrar while PVR processing. The domain
registrar needs to verify that the "proximity-registrar-cert" field
in the PVR matches its own registrar LDevID certificate. In
addition, the domain registrar needs to verify the association of the
pledge to its domain based on the product-serial-number contained in
the PVR and in the IDevID certificate of the pledge. (This is just
part of the supply chain integration). Moreover, the domain
registrar verifies if the Registrar-Agent is authorized to interact
with the pledge for voucher-requests and enroll-requests, based on
the EE (RegAgt) certificate data contained in the PVR.
Misbinding of a pledge by a faked domain registrar is countered as
described in BRSKI security considerations [RFC8995] (Section 11.4).
10.3. Misuse of Registrar-Agent Credentials
Concerns of misusage of a Registrar-Agent with a valid EE (RegAgt)
certificate may be addressed by utilizing short-lived certificates
(e.g., valid for a day) to authenticate the Registrar-Agent against
the domain registrar. The EE (RegAgt) certificate may have been
acquired by a prior BRSKI run for the Registrar-Agent, if an IDevID
is available on Registrar-Agent. Alternatively, the EE (RegAgt)
certificate may be acquired by a service technician from the domain
PKI system in an authenticated way.
In addition it is required that the EE (RegAgt) certificate is valid
for the complete bootstrapping phase. This avoids that a Registrar-
Agent could be misused to create arbitrary "agent-signed-data"
objects to perform an authorized bootstrapping of a rogue pledge at a
later point in time. In this misuse "agent-signed-data" could be
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dated after the validity time of the EE (RegAgt) certificate, due to
missing trusted timestamp in the Registrar-Agents signature. To
address this, the registrar SHOULD verify the certificate used to
create the signature on "agent-signed-data". Furthermore the
registrar also verifies the EE (RegAgt) certificate used in the TLS
handshake with the Registrar-Agent. If both certificates are
verified successfully, the Registrar-Agent's signature can be
considered as valid.
10.4. Misuse of DNS-SD with mDNS to obtain list of pledges
To discover a specific pledge a Registrar-Agent may request the
service name in combination with the product-serial-number of a
specific pledge. The pledge reacts on this if its product-serial-
number is part of the request message.
If the Registrar-Agent performs DNS-based Service Discovery without a
specific product-serial-number, all pledges in the domain react if
the functionality is supported. This functionality enumerates and
reveals the information of devices available in the domain. The
information about this is provided here as a feature to support the
commissioning of devices. A manufacturer may decide to support this
feature only for devices not possessing a LDevID or to not support
this feature at all, to avoid an enumeration in an operative domain.
10.5. YANG Module Security Considerations
The enhanced voucher-request described in [I-D.ietf-anima-rfc8366bis]
is based on [RFC8995], but uses a different encoding based on
[I-D.ietf-anima-jws-voucher]. The security considerations as
described in [RFC8995] Section 11.7 (Security Considerations) apply.
The YANG module specified in [I-D.ietf-anima-rfc8366bis] defines the
schema for data that is subsequently encapsulated by a JOSE signed-
data Content-type as described in [I-D.ietf-anima-jws-voucher]. As
such, all of the YANG-modeled data is protected against modification.
The use of YANG to define data structures via the [RFC8971]
"structure" statement, is relatively new and distinct from the
traditional use of YANG to define an API accessed by network
management protocols such as NETCONF [RFC6241] and RESTCONF
[RFC8040]. For this reason, these guidelines do not follow the
template described by [RFC8407] Section 3.7 (Security Considerations
Section).
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11. Acknowledgments
We would like to thank the various reviewers, in particular Brian E.
Carpenter, Oskar Camenzind, Hendrik Brockhaus, and Ingo Wenda for
their input and discussion on use cases and call flows. Further
review input was provided by Jesser Bouzid, Dominik Tacke, and
Christian Spindler. Special thanks to Esko Dijk for the in deep
review and the improving proposals. Support in PoC implementations
and comments resulting from the implementation was provided by Hong
Rui Li and He Peng Jia.
12. References
12.1. Normative References
[I-D.ietf-anima-jws-voucher]
Werner, T. and M. Richardson, "JWS signed Voucher
Artifacts for Bootstrapping Protocols", Work in Progress,
Internet-Draft, draft-ietf-anima-jws-voucher-09, 29 August
2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
anima-jws-voucher-09>.
[I-D.ietf-anima-rfc8366bis]
Watsen, K., Richardson, M., Pritikin, M., Eckert, T. T.,
and Q. Ma, "A Voucher Artifact for Bootstrapping
Protocols", Work in Progress, Internet-Draft, draft-ietf-
anima-rfc8366bis-10, 22 August 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-anima-
rfc8366bis-10>.
[I-D.ietf-netconf-sztp-csr]
Watsen, K., Housley, R., and S. Turner, "Conveying a
Certificate Signing Request (CSR) in a Secure Zero Touch
Provisioning (SZTP) Bootstrapping Request", Work in
Progress, Internet-Draft, draft-ietf-netconf-sztp-csr-14,
2 March 2022, <https://datatracker.ietf.org/doc/html/
draft-ietf-netconf-sztp-csr-14>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
DOI 10.17487/RFC6762, February 2013,
<https://www.rfc-editor.org/rfc/rfc6762>.
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[RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
<https://www.rfc-editor.org/rfc/rfc6763>.
[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
"Enrollment over Secure Transport", RFC 7030,
DOI 10.17487/RFC7030, October 2013,
<https://www.rfc-editor.org/rfc/rfc7030>.
[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, <https://www.rfc-editor.org/rfc/rfc7515>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/rfc/rfc8040>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8366] Watsen, K., Richardson, M., Pritikin, M., and T. Eckert,
"A Voucher Artifact for Bootstrapping Protocols",
RFC 8366, DOI 10.17487/RFC8366, May 2018,
<https://www.rfc-editor.org/rfc/rfc8366>.
[RFC8610] Birkholz, H., Vigano, C., and C. Bormann, "Concise Data
Definition Language (CDDL): A Notational Convention to
Express Concise Binary Object Representation (CBOR) and
JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,
June 2019, <https://www.rfc-editor.org/rfc/rfc8610>.
[RFC8615] Nottingham, M., "Well-Known Uniform Resource Identifiers
(URIs)", RFC 8615, DOI 10.17487/RFC8615, May 2019,
<https://www.rfc-editor.org/rfc/rfc8615>.
[RFC8995] Pritikin, M., Richardson, M., Eckert, T., Behringer, M.,
and K. Watsen, "Bootstrapping Remote Secure Key
Infrastructure (BRSKI)", RFC 8995, DOI 10.17487/RFC8995,
May 2021, <https://www.rfc-editor.org/rfc/rfc8995>.
[RFC9360] Schaad, J., "CBOR Object Signing and Encryption (COSE):
Header Parameters for Carrying and Referencing X.509
Certificates", RFC 9360, DOI 10.17487/RFC9360, February
2023, <https://www.rfc-editor.org/rfc/rfc9360>.
12.2. Informative References
Fries, et al. Expires 23 May 2024 [Page 72]
Internet-Draft BRSKI-PRM November 2023
[androidnsd]
"Android Developer: Connect devices wirelessly", archived
at https://web.archive.org/web/20230000000000*/https://dev
eloper.android.com/training/connect-devices-wirelessly,
n.d., <https://developer.android.com/training/connect-
devices-wirelessly>.
[androidtrustfail]
"Security with Network Protocols", archived at https://web
.archive.org/web/20230326153937/https://developer.android.
com/training/articles/security-ssl, n.d.,
<https://developer.android.com/training/articles/security-
ssl>.
[BRSKI-PRM-abstract]
"Abstract BRSKI-PRM Protocol Overview", March 2022,
<https://datatracker.ietf.org/meeting/113/materials/
slides-113-anima-update-on-brski-with-pledge-in-responder-
mode-brski-prm-00>.
[I-D.eckert-anima-brski-discovery]
Eckert, T. T., von Oheimb, D., and E. Dijk, "Discovery for
BRSKI variations", Work in Progress, Internet-Draft,
draft-eckert-anima-brski-discovery-01, 23 October 2023,
<https://datatracker.ietf.org/doc/html/draft-eckert-anima-
brski-discovery-01>.
[I-D.ietf-anima-brski-ae]
von Oheimb, D., Fries, S., and H. Brockhaus, "BRSKI-AE:
Alternative Enrollment Protocols in BRSKI", Work in
Progress, Internet-Draft, draft-ietf-anima-brski-ae-07, 17
November 2023, <https://datatracker.ietf.org/doc/html/
draft-ietf-anima-brski-ae-07>.
[I-D.irtf-t2trg-taxonomy-manufacturer-anchors]
Richardson, M., "A Taxonomy of operational security
considerations for manufacturer installed keys and Trust
Anchors", Work in Progress, Internet-Draft, draft-irtf-
t2trg-taxonomy-manufacturer-anchors-02, 6 August 2023,
<https://datatracker.ietf.org/doc/html/draft-irtf-t2trg-
taxonomy-manufacturer-anchors-02>.
[I-D.richardson-anima-registrar-considerations]
Richardson, M. and W. Pan, "Operational Considerations for
BRSKI Registrar", Work in Progress, Internet-Draft, draft-
richardson-anima-registrar-considerations-07, 11 May 2023,
<https://datatracker.ietf.org/doc/html/draft-richardson-
anima-registrar-considerations-07>.
Fries, et al. Expires 23 May 2024 [Page 73]
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[I-D.richardson-emu-eap-onboarding]
DeKok, A. and M. Richardson, "EAP defaults for devices
that need to onboard", Work in Progress, Internet-Draft,
draft-richardson-emu-eap-onboarding-03, 2 April 2023,
<https://datatracker.ietf.org/doc/html/draft-richardson-
emu-eap-onboarding-03>.
[IEEE-802.1AR]
Institute of Electrical and Electronics Engineers, "IEEE
802.1AR Secure Device Identifier", IEEE 802.1AR, June
2018.
[onpath] "can an on-path attacker drop traffic?", n.d.,
<https://mailarchive.ietf.org/arch/msg/saag/
m1r9uo4xYznOcf85Eyk0Rhut598/>.
[RFC2986] Nystrom, M. and B. Kaliski, "PKCS #10: Certification
Request Syntax Specification Version 1.7", RFC 2986,
DOI 10.17487/RFC2986, November 2000,
<https://www.rfc-editor.org/rfc/rfc2986>.
[RFC5272] Schaad, J. and M. Myers, "Certificate Management over CMS
(CMC)", RFC 5272, DOI 10.17487/RFC5272, June 2008,
<https://www.rfc-editor.org/rfc/rfc5272>.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer
Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
2011, <https://www.rfc-editor.org/rfc/rfc6125>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/rfc/rfc6241>.
[RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
Application Protocol (CoAP)", RFC 7252,
DOI 10.17487/RFC7252, June 2014,
<https://www.rfc-editor.org/rfc/rfc7252>.
[RFC8152] Schaad, J., "CBOR Object Signing and Encryption (COSE)",
RFC 8152, DOI 10.17487/RFC8152, July 2017,
<https://www.rfc-editor.org/rfc/rfc8152>.
Fries, et al. Expires 23 May 2024 [Page 74]
Internet-Draft BRSKI-PRM November 2023
[RFC8407] Bierman, A., "Guidelines for Authors and Reviewers of
Documents Containing YANG Data Models", BCP 216, RFC 8407,
DOI 10.17487/RFC8407, October 2018,
<https://www.rfc-editor.org/rfc/rfc8407>.
[RFC8792] Watsen, K., Auerswald, E., Farrel, A., and Q. Wu,
"Handling Long Lines in Content of Internet-Drafts and
RFCs", RFC 8792, DOI 10.17487/RFC8792, June 2020,
<https://www.rfc-editor.org/rfc/rfc8792>.
[RFC8971] Pallagatti, S., Ed., Mirsky, G., Ed., Paragiri, S.,
Govindan, V., and M. Mudigonda, "Bidirectional Forwarding
Detection (BFD) for Virtual eXtensible Local Area Network
(VXLAN)", RFC 8971, DOI 10.17487/RFC8971, December 2020,
<https://www.rfc-editor.org/rfc/rfc8971>.
[RFC8990] Bormann, C., Carpenter, B., Ed., and B. Liu, Ed., "GeneRic
Autonomic Signaling Protocol (GRASP)", RFC 8990,
DOI 10.17487/RFC8990, May 2021,
<https://www.rfc-editor.org/rfc/rfc8990>.
[RFC9052] Schaad, J., "CBOR Object Signing and Encryption (COSE):
Structures and Process", STD 96, RFC 9052,
DOI 10.17487/RFC9052, August 2022,
<https://www.rfc-editor.org/rfc/rfc9052>.
[RFC9053] Schaad, J., "CBOR Object Signing and Encryption (COSE):
Initial Algorithms", RFC 9053, DOI 10.17487/RFC9053,
August 2022, <https://www.rfc-editor.org/rfc/rfc9053>.
[RFC9110] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "HTTP Semantics", STD 97, RFC 9110,
DOI 10.17487/RFC9110, June 2022,
<https://www.rfc-editor.org/rfc/rfc9110>.
[RFC9238] Richardson, M., Latour, J., and H. Habibi Gharakheili,
"Loading Manufacturer Usage Description (MUD) URLs from QR
Codes", RFC 9238, DOI 10.17487/RFC9238, May 2022,
<https://www.rfc-editor.org/rfc/rfc9238>.
Appendix A. Examples
These examples are folded according to [RFC8792] Single Backslash
rule.
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A.1. Example Pledge Voucher-Request - PVR (from Pledge to Registrar-
Agent)
The following is an example request sent from a Pledge to the
Registrar-Agent, in "General JWS JSON Serialization". The message
size of this PVR is: 4649 bytes
=============== NOTE: '\' line wrapping per RFC 8792 ================
{
"payload":
"eyJpZXRmLXZvdWNoZXItcmVxdWVzdC1wcm06dm91Y2hlciI6eyJhc3NlcnRpb24\
iOiJhZ2VudC1wcm94aW1pdHkiLCJzZXJpYWwtbnVtYmVyIjoiMDEyMzQ1Njc4OSIsIm5\
vbmNlIjoiTDNJSjZocHRIQ0lRb054YWFiOUhXQT09IiwiY3JlYXRlZC1vbiI6IjIwMjI\
tMDQtMjZUMDU6MTY6MTcuNzA5WiIsImFnZW50LXByb3ZpZGVkLXByb3hpbWl0eS1yZWd\
pc3RyYXItY2VydCI6Ik1JSUI0akNDQVlpZ0F3SUJBZ0lHQVhZNzJiYlpNQW9HQ0NxR1N\
NNDlCQU1DTURVeEV6QVJCZ05WQkFvTUNrMTVRblZ6YVc1bGMzTXhEVEFMQmdOVkJBY01\
CRk5wZEdVeER6QU5CZ05WQkFNTUJsUmxjM1JEUVRBZUZ3MHlNREV5TURjd05qRTRNVEp\
hRncwek1ERXlNRGN3TmpFNE1USmFNRDR4RXpBUkJnTlZCQW9NQ2sxNVFuVnphVzVsYzN\
NeERUQUxCZ05WQkFjTUJGTnBkR1V4R0RBV0JnTlZCQU1NRDBSdmJXRnBibEpsWjJsemR\
ISmhjakJaTUJNR0J5cUdTTTQ5QWdFR0NDcUdTTTQ5QXdFSEEwSUFCQmsxNksvaTc5b1J\
rSzVZYmVQZzhVU1I4L3VzMWRQVWlaSE10b2tTZHFLVzVmbldzQmQrcVJMN1dSZmZlV2t\
5Z2Vib0pmSWxsdXJjaTI1d25oaU9WQ0dqZXpCNU1CMEdBMVVkSlFRV01CUUdDQ3NHQVF\
VRkJ3TUJCZ2dyQmdFRkJRY0RIREFPQmdOVkhROEJBZjhFQkFNQ0I0QXdTQVlEVlIwUkJ\
FRXdQNElkY21WbmFYTjBjbUZ5TFhSbGMzUXVjMmxsYldWdWN5MWlkQzV1WlhTQ0huSmx\
aMmx6ZEhKaGNpMTBaWE4wTmk1emFXVnRaVzV6TFdKMExtNWxkREFLQmdncWhrak9QUVF\
EQWdOSUFEQkZBaUJ4bGRCaFpxMEV2NUpMMlByV0N0eVM2aERZVzF5Q08vUmF1YnBDN01\
hSURnSWhBTFNKYmdMbmdoYmJBZzBkY1dGVVZvL2dHTjAvand6SlowU2wyaDR4SVhrMSI\
sImFnZW50LXNpZ25lZC1kYXRhIjoiZXlKd1lYbHNiMkZrSWpvaVpYbEtjRnBZVW0xTVd\
GcDJaRmRPYjFwWVNYUmpiVlo0WkZkV2VtUkRNWGRqYlRBMldWZGtiR0p1VVhSak1teHV\
ZbTFXYTB4WFVtaGtSMFZwVDI1emFWa3pTbXhaV0ZKc1drTXhkbUpwU1RaSmFrbDNUV3B\
KZEUxRVVYUk5hbHBWVFVSVk5rMUVZelpPUkVWMVRrUlJORmRwU1hOSmJrNXNZMjFzYUd\
KRE1YVmtWekZwV2xoSmFVOXBTWGROVkVsNlRrUlZNazU2WnpWSmJqRTVJaXdpYzJsbmJ\
tRjBkWEpsY3lJNlczc2ljSEp2ZEdWamRHVmtJam9pWlhsS2NtRlhVV2xQYVVwWlkwaHd\
jMVJWZERSaVNFSkNUbXBvYWxaVVZrZFZWVEZaVmxoYWRWTldVVEpWV0dNNVNXbDNhVmx\
YZUc1SmFtOXBVbFpOZVU1VVdXbG1VU0lzSW5OcFoyNWhkSFZ5WlNJNklrY3pWM2hHU0d\
WMFdGQTRiR3hTVmkwNWRXSnlURmxxU25aUllUWmZlUzFRYWxGWk5FNWhkMW81Y0ZKaGI\
yeE9TbTlFTm1SbFpXdHVTVjlGV0daemVWWlRZbmM0VTBONlRWcE1iakJoUVhWb2FVZFp\
UakJSSW4xZGZRPT0iLCJhZ2VudC1zaWduLWNlcnQiOlsiTUlJQjFEQ0NBWHFnQXdJQkF\
nSUVZbWQ0T1RBS0JnZ3Foa2pPUFFRREFqQStNUk13RVFZRFZRUUtEQXBOZVVKMWMybHV\
aWE56TVEwd0N3WURWUVFIREFSVGFYUmxNUmd3RmdZRFZRUUREQTlVWlhOMFVIVnphRTF\
2WkdWc1EwRXdIaGNOTWpJd05ESTJNRFEwTWpNeldoY05Nekl3TkRJMk1EUTBNak16V2p\
BOU1STXdFUVlEVlFRS0RBcE5lVUoxYzJsdVpYTnpNUTB3Q3dZRFZRUUhEQVJUYVhSbE1\
SY3dGUVlEVlFRRERBNVNaV2RwYzNSeVlYSkJaMlZ1ZERCWk1CTUdCeXFHU000OUFnRUd\
DQ3FHU000OUF3RUhBMElBQkd4bHJOZmozaVJiNy9CUW9kVys1WWlvT3poK2pJdHlxdVJ\
JTy9XejdZb1czaXdEYzNGeGV3TFZmekNyNU52RDEzWmFGYjdmcmFuK3Q5b3RZNVdMaEo\
2alp6QmxNQTRHQTFVZER3RUIvd1FFQXdJSGdEQWZCZ05WSFNNRUdEQVdnQlJ2b1QxdWR\
lMmY2TEVRaFU3SEhqK3ZKL2Q3SXpBZEJnTlZIUTRFRmdRVVhwemxNS3hscEE2OGNVNUZ\
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RTVhVdm5JVDZRd3dFd1lEVlIwbEJBd3dDZ1lJS3dZQkJRVUhBd0l3Q2dZSUtvWkl6ajB\
FQXdJRFNBQXdSUUlnYzJ5NnhvT3RvUUJsSnNnbE9MMVZ4SEdvc1R5cEVxUmZ6MFF2NFp\
FUHY0d0NJUUNWeWIyRjl6VjNuOTUrb2xnZkZKZ1pUV0V6NGRTYUYzaHpSUWIzWnVCMjl\
RPT0iLCJNSUlCekRDQ0FYR2dBd0lCQWdJRVhYakhwREFLQmdncWhrak9QUVFEQWpBMU1\
STXdFUVlEVlFRS0RBcE5lVUoxYzJsdVpYTnpNUTB3Q3dZRFZRUUhEQVJUYVhSbE1ROHd\
EUVlEVlFRRERBWlVaWE4wUTBFd0hoY05NVGt3T1RFeE1UQXdPRE0yV2hjTk1qa3dPVEV\
4TVRBd09ETTJXakErTVJNd0VRWURWUVFLREFwTmVVSjFjMmx1WlhOek1RMHdDd1lEVlF\
RSERBUlRhWFJsTVJnd0ZnWURWUVFEREE5VVpYTjBVSFZ6YUUxdlpHVnNRMEV3V1RBVEJ\
nY3Foa2pPUFFJQkJnZ3Foa2pPUFFNQkJ3TkNBQVRsRzBmd1QzM29leloxdmtIUWJldGV\
ibWorQm9WK1pGc2pjZlF3MlRPa0pQaE9rT2ZBYnU5YlMxcVppOHlhRVY4b2VyS2wvNlp\
YYmZ4T21CanJScmNYbzJZd1pEQVNCZ05WSFJNQkFmOEVDREFHQVFIL0FnRUFNQTRHQTF\
VZER3RUIvd1FFQXdJQ0JEQWZCZ05WSFNNRUdEQVdnQlRvWklNelFkc0Qvai8rZ1gvN2N\
CSnVjSC9YbWpBZEJnTlZIUTRFRmdRVWI2RTliblh0bitpeEVJVk94eDQvcnlmM2V5TXd\
DZ1lJS29aSXpqMEVBd0lEU1FBd1JnSWhBUG5CMHcxTkN1cmhNeEp3d2ZqejdnRGlpeGt\
VWUxQU1o5ZU45a29oTlFVakFpRUF3NFk3bHR4V2lQd0t0MUo5bmp5ZkRObDVNdUVEQml\
teFIzQ1hvWktHUXJVPSJdfX0",
"signatures":[{
"protected":"eyJ4NWMiOlsiTUlJQitUQ0NBYUNnQXdJQkFnSUdBWG5WanNVN\
U1Bb0dDQ3FHU000OUJBTUNNRDB4Q3pBSkJnTlZCQVlUQWtGUk1SVXdFd1lEVlFRS0RBe\
EthVzVuU21sdVowTnZjbkF4RnpBVkJnTlZCQU1NRGtwcGJtZEthVzVuVkdWemRFTkJNQ\
0FYRFRJeE1EWXdOREExTkRZeE5Gb1lEems1T1RreE1qTXhNak0xT1RVNVdqQlNNUXN3Q\
1FZRFZRUUdFd0pCVVRFVk1CTUdBMVVFQ2d3TVNtbHVaMHBwYm1kRGIzSndNUk13RVFZR\
FZRUUZFd293TVRJek5EVTJOemc1TVJjd0ZRWURWUVFEREE1S2FXNW5TbWx1WjBSbGRtb\
GpaVEJaTUJNR0J5cUdTTTQ5QWdFR0NDcUdTTTQ5QXdFSEEwSUFCQzc5bGlhUmNCalpjR\
UVYdzdyVWVhdnRHSkF1SDRwazRJNDJ2YUJNc1UxMWlMRENDTGtWaHRVVjIxbXZhS0N2T\
XgyWStTTWdROGZmd0wyM3ozVElWQldqZFRCek1Dc0dDQ3NHQVFVRkJ3RWdCQjhXSFcxa\
GMyRXRkR1Z6ZEM1emFXVnRaVzV6TFdKMExtNWxkRG81TkRRek1COEdBMVVkSXdRWU1CY\
UFGRlFMak56UFwvU1wva291alF3amc1RTVmdndjWWJNQk1HQTFVZEpRUU1NQW9HQ0NzR\
0FRVUZCd01DTUE0R0ExVWREd0VCXC93UUVBd0lIZ0RBS0JnZ3Foa2pPUFFRREFnTkhBR\
EJFQWlCdTN3UkJMc0pNUDVzTTA3MEgrVUZyeU5VNmdLekxPUmNGeVJST2xxcUhpZ0lnW\
ENtSkxUekVsdkQycG9LNmR4NmwxXC91eW1UbmJRRERmSmxhdHVYMlJvT0U9Il0sImFsZ\
yI6IkVTMjU2In0",
"signature":"Y_ohapnmvbwjLuUicOB7NAmbGM7igBfpUlkKUuSNdG-eDI4BQ\
yuXZ2aw93zZId45R7XxAK-12YKIx6qLjiPjMw"
}]
}
Figure 25: Example Pledge Voucher-Request - PVR
A.2. Example Parboiled Registrar Voucher-Request - RVR (from Registrar
to MASA)
The term parboiled refers to food which is partially cooked. In
[RFC8995], the term refers to a Pledge voucher-request (PVR) which
has been received by the Registrar, and then has been processed by
the Registrar ("cooked"), and is now being forwarded to the MASA.
Fries, et al. Expires 23 May 2024 [Page 77]
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The following is an example Registrar voucher-request (RVR) sent from
the Registrar to the MASA, in "General JWS JSON Serialization". Note
that the previous PVR can be seen in the payload as "prior-signed-
voucher-request". The message size of this RVR is: 13257 bytes
=============== NOTE: '\' line wrapping per RFC 8792 ================
{
"payload":
"eyJpZXRmLXZvdWNoZXItcmVxdWVzdC1wcm06dm91Y2hlciI6eyJhc3NlcnRpb24\
iOiJhZ2VudC1wcm94aW1pdHkiLCJzZXJpYWwtbnVtYmVyIjoiY2FmZmUtOTg3NDUiLCJ\
ub25jZSI6ImM1VEVPb29NTE5hNEN4L1UrVExoQ3c9PSIsInByaW9yLXNpZ25lZC12b3V\
jaGVyLXJlcXVlc3QiOiJleUp3WVhsc2IyRmtJam9pWlhsS2NGcFlVbTFNV0ZwMlpGZE9\
iMXBZU1hSamJWWjRaRmRXZW1SRE1YZGpiVEEyWkcwNU1Wa3lhR3hqYVVrMlpYbEthR01\
6VG14amJsSndZakkwYVU5cFNtaGFNbFoxWkVNeGQyTnRPVFJoVnpGd1pFaHJhVXhEU25\
wYVdFcHdXVmQzZEdKdVZuUlpiVlo1U1dwdmFWa3lSbTFhYlZWMFQxUm5NMDVFVldsTVE\
wcDFZakkxYWxwVFNUWkpiVTB4VmtWV1VHSXlPVTVVUlRWb1RrVk9ORXd4VlhKV1JYaHZ\
VVE5qT1ZCVFNYTkpiVTU1V2xkR01GcFhVWFJpTWpScFQybEplVTFFU1hsTVZFRjVURlJ\
KZVZaRVFUTlBhazE2VDJwQk5FeHFSVFZPYkc5cFRFTkthRm95Vm5Wa1F6RjNZMjA1TW1\
GWFVteGFRekYzWTIwNU5HRlhNWEJrU0d0MFkyMVdibUZZVGpCamJVWjVURmRPYkdOdVV\
XbFBhVXBPVTFWc1JGSkdVa1JSTUVacFZESmtRbVF3YkVOUlYyUktVakJHV1ZkWVRuZFR\
WMVoyVkZWR2RsSXdUa1JqVldSVVZGUlJOVkZyUms1Uk1ERkhaRE5vUkdWclJrdFJiV1J\
QVm10S1FsZFdVa0poTUZwVFZGWktTbVF3VmtKWFZWSlhWVlpHVEZKRlJuTlViVlpXVkc\
1YWFWZEZTbTlaYlRWeVpVVmFWVkZXVWtOYU1EVlhVV3RHZWxSVlVrWk5WRlpXVFRGYWN\
GbDZTbk5oTWtaWVVtNXNiRlpGVmxGVVZVVjNVakJGZUZaVlZrTmtNMlJJVmtab2MxWkh\
SbGxWYlhoT1ZXdFdNMUpJWkZwU1JscFNWVlZTUlZGWGFFOWFWbHBQWTBkU1NGWnJVbEp\
XUlVac1VtNWpkMlZWTVVWU1dHeE9Va1pHTTFSdWNFcE5WVFZGWVVkR1IyUjZRalpVVlZ\
KR1pWVXhSVlZZWkU5bGEydDRWR3RTYjFsVk1VaFRXR2hFWld0R1MxRnRaRTlXYTBwQ1Y\
xWlNRbUV3V2xOVVZrcEtaREJXUWxkVlVsZFZWa1pNVWtWR2MxUnRWbFpVYmxwcFYwVkt\
iMWx0TlhKbFJWcEZVVlpPUTFvd05WZFJhMFo2VkZWTmQwMVVWbFpOTVZwd1dYcEtjMkV\
4YkZsVGFsWk9WVlJvTTFKR1JscFNSbHBTVlZWb1JWRldjRTlhVmxwUFkwZFNTRlpZYUV\
oU1JVWllVVzFrVDFaclNrSlVWVEZGVFVSRk1WWlVTbk5OUm5CWFUyMTRZVTF0ZURaYVJ\
XaExZVWRPY1ZGc2NFNVJhekZJVVc1c2VGSXhUazVPUkd4Q1dqQldTRkV3VG5oU01VNU9\
Ua1JzUW1Rd1ZrbFJWRUpLVVZWS1NsVklhRmhrVlRGSlVucG9TMVJIV2taVlJVVTFUMWh\
hZDAxdVZrbFNWVFZxVlROc2JWa3pWVE5VUjJSYVRraEJlRTVGUmtOT01GSk9XbFJGTkU\
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Fries, et al. Expires 23 May 2024 [Page 78]
Internet-Draft BRSKI-PRM November 2023
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Fries, et al. Expires 23 May 2024 [Page 79]
Internet-Draft BRSKI-PRM November 2023
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Fries, et al. Expires 23 May 2024 [Page 80]
Internet-Draft BRSKI-PRM November 2023
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ZRFZSMFBBUUhcL0JBUURBZ2VBTUFvR0NDcUdTTTQ5QkFNQ0EwZ0FNRVVDSUhOK3VBbUp\
ldVhlc1wveWQxd1M0Mlo0RFhKNEptMWErZzNYa1pnZjhUaGxuQWlFQXBVdTZzZnljRWt\
veDdSWlhtZitLOHc0cDZzUldyamExUVJwWTAyNjQxSFk9IiwiTUlJQjhEQ0NBWmVnQXd\
JQkFnSUdBWEJoTUtZQk1Bb0dDQ3FHU000OUJBTUNNRnd4Q3pBSkJnTlZCQVlUQWtGUk1\
SSXdFQVlEVlFRS0RBbE5lVU52YlhCaGJua3hGVEFUQmdOVkJBc01ERTE1VTNWaWMybGt\
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hV0Z5ZVRFUE1BMEdBMVVFQnd3R1RYbFRhWFJsTVJFd0R3WURWUVFEREFoTmVWTnBkR1Z\
EUVRBZUZ3MHlNREF5TWpBd05qQXlNak5hRncwek1EQXlNakF3TmpBeU1qTmFNRnd4Q3p\
BSkJnTlZCQVlUQWtGUk1SSXdFQVlEVlFRS0RBbE5lVU52YlhCaGJua3hGVEFUQmdOVkJ\
Bc01ERTE1VTNWaWMybGthV0Z5ZVRFUE1BMEdBMVVFQnd3R1RYbFRhWFJsTVJFd0R3WUR\
WUVFEREFoTmVWTnBkR1ZEUVRCWk1CTUdCeXFHU000OUFnRUdDQ3FHU000OUF3RUhBMEl\
BQkluQ3VoV1ZzZ2NONzFvWmVzMUZHXC9xZFZnTVBva01wZlMyNzFcL2V5SWNcL29EVmJ\
NRkhDYmV2SjVMTTgxOTVOYVpLTlNvSFAzS3dMeXVCaDh2MncwOVp1alJUQkRNQklHQTF\
VZEV3RUJcL3dRSU1BWUJBZjhDQVFFd0RnWURWUjBQQVFIXC9CQVFEQWdJRU1CMEdBMVV\
kRGdRV0JCUXp4endwUnBMeVwvck1VWXphaDJzMTNlVTlnRnpBS0JnZ3Foa2pPUFFRREF\
nTkhBREJFQWlCZGJIU212YW9qaDBpZWtaSUtOVzhRMGxTbGI1K0RLTlFcL05LY1I3dWx\
6dGdJZ2RwejZiUkYyREZtcGlKb3JCMkd5VmE4YVdkd2xIc0RvRVdZY0k0UEdKYmc9Il0\
sImFsZyI6IkVTMjU2In0",
"signature":"67t3n8zyEek4IM2Ko3Y_UvE1hzp794QFNTqG-HzTrBQtE4_4-yS\
yyFd3kP6YCn35YYJ7yK35d3styo_yoiPfKA"
}]
}
Figure 26: Example Registrar Voucher-Request - RVR
A.3. Example Voucher-Response (from MASA to Pledge, via Registrar and
Registrar-Agent)
The following is an example voucher-response from MASA to Pledge via
Registrar and Registrar-Agent, in "General JWS JSON Serialization".
The message size of this Voucher is: 1916 bytes
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=============== NOTE: '\' line wrapping per RFC 8792 ================
{
"payload":"eyJpZXRmLXZvdWNoZXI6dm91Y2hlciI6eyJhc3NlcnRpb24iOiJhZ2V\
udC1wcm94aW1pdHkiLCJzZXJpYWwtbnVtYmVyIjoiMDEyMzQ1Njc4OSIsIm5vbmNlIjo\
iTDNJSjZocHRIQ0lRb054YWFiOUhXQT09IiwiY3JlYXRlZC1vbiI6IjIwMjItMDQtMjZ\
UMDU6MTY6MjguNzI2WiIsInBpbm5lZC1kb21haW4tY2VydCI6Ik1JSUJwRENDQVVtZ0F\
3SUJBZ0lHQVcwZUx1SCtNQW9HQ0NxR1NNNDlCQU1DTURVeEV6QVJCZ05WQkFvTUNrMTV\
RblZ6YVc1bGMzTXhEVEFMQmdOVkJBY01CRk5wZEdVeER6QU5CZ05WQkFNTUJsUmxjM1J\
EUVRBZUZ3MHhPVEE1TVRFd01qTTNNekphRncweU9UQTVNVEV3TWpNM016SmFNRFV4RXp\
BUkJnTlZCQW9NQ2sxNVFuVnphVzVsYzNNeERUQUxCZ05WQkFjTUJGTnBkR1V4RHpBTkJ\
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CT2t2a1RIdThRbFQzRkhKMVVhSTcrV3NIT2IwVVMzU0FMdEc1d3VLUURqaWV4MDYvU2N\
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BaUVBdHhRMytJTEdCUEl0U2g0YjlXWGhYTnVocVNQNkgrYi9MQy9mVllEalE2b0NJUUR\
HMnVSQ0hsVnEzeWhCNThUWE1VYnpIOCtPbGhXVXZPbFJEM1ZFcURkY1F3PT0ifX0",
"signatures":[{
"protected":"eyJ4NWMiOlsiTUlJQmt6Q0NBVGlnQXdJQkFnSUdBV0ZCakNrWU1\
Bb0dDQ3FHU000OUJBTUNNRDB4Q3pBSkJnTlZCQVlUQWtGUk1SVXdFd1lEVlFRS0RBeEt\
hVzVuU21sdVowTnZjbkF4RnpBVkJnTlZCQU1NRGtwcGJtZEthVzVuVkdWemRFTkJNQjR\
YRFRFNE1ERXlPVEV3TlRJME1Gb1hEVEk0TURFeU9URXdOVEkwTUZvd1R6RUxNQWtHQTF\
VRUJoTUNRVkV4RlRBVEJnTlZCQW9NREVwcGJtZEthVzVuUTI5eWNERXBNQ2NHQTFVRUF\
3d2dTbWx1WjBwcGJtZERiM0p3SUZadmRXTm9aWElnVTJsbmJtbHVaeUJMWlhrd1dUQVR\
CZ2NxaGtqT1BRSUJCZ2dxaGtqT1BRTUJCd05DQUFTQzZiZUxBbWVxMVZ3NmlRclJzOFI\
wWlcrNGIxR1d5ZG1XczJHQU1GV3diaXRmMm5JWEgzT3FIS1Z1OHMyUnZpQkdOaXZPS0d\
CSEh0QmRpRkVaWnZiN294SXdFREFPQmdOVkhROEJBZjhFQkFNQ0I0QXdDZ1lJS29aSXp\
qMEVBd0lEU1FBd1JnSWhBSTRQWWJ4dHNzSFAyVkh4XC90elVvUVwvU3N5ZEwzMERRSU5\
FdGNOOW1DVFhQQWlFQXZJYjNvK0ZPM0JUbmNMRnNhSlpSQWtkN3pPdXNuXC9cL1pLT2F\
FS2JzVkRpVT0iXSwiYWxnIjoiRVMyNTYifQ",
"signature":"0TB5lr-cs1jqka2vNbQm3bBYWfLJd8zdVKIoV53eo2YgSITnKKY\
TvHMUw0wx9wdyuNVjNoAgLysNIgEvlcltBw"
}]
}
Figure 27: Example Voucher-Response from MASA
A.4. Example Voucher-Response, MASA issued Voucher with additional
Registrar signature (from MASA to Pledge, via Registrar and
Registrar-Agent)
The following is an example voucher-response from MASA to Pledge via
Registrar and Registrar-Agent, in "General JWS JSON Serialization".
The message size of this Voucher is: 3006 bytes
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=============== NOTE: '\' line wrapping per RFC 8792 ================
{
"payload":"eyJpZXRmLXZvdWNoZXI6dm91Y2hlciI6eyJhc3NlcnRpb24iOiJhZ2V\
udC1wcm94aW1pdHkiLCJzZXJpYWwtbnVtYmVyIjoiMDEyMzQ1Njc4OSIsIm5vbmNlIjo\
iUUJiSXMxNTJzbkFvVzdSeVFMWENvZz09IiwiY3JlYXRlZC1vbiI6IjIwMjItMDktMjl\
UMDM6Mzc6MjYuMzgyWiIsInBpbm5lZC1kb21haW4tY2VydCI6Ik1JSUJwRENDQVVtZ0F\
3SUJBZ0lHQVcwZUx1SCtNQW9HQ0NxR1NNNDlCQU1DTURVeEV6QVJCZ05WQkFvTUNrMTV\
RblZ6YVc1bGMzTXhEVEFMQmdOVkJBY01CRk5wZEdVeER6QU5CZ05WQkFNTUJsUmxjM1J\
EUVRBZUZ3MHhPVEE1TVRFd01qTTNNekphRncweU9UQTVNVEV3TWpNM016SmFNRFV4RXp\
BUkJnTlZCQW9NQ2sxNVFuVnphVzVsYzNNeERUQUxCZ05WQkFjTUJGTnBkR1V4RHpBTkJ\
nTlZCQU1NQmxSbGMzUkRRVEJaTUJNR0J5cUdTTTQ5QWdFR0NDcUdTTTQ5QXdFSEEwSUF\
CT2t2a1RIdThRbFQzRkhKMVVhSTcrV3NIT2IwVVMzU0FMdEc1d3VLUURqaWV4MDYvU2N\
ZNVBKaWJ2Z0hUQitGL1FUamdlbEhHeTFZS3B3Y05NY3NTeWFqUlRCRE1CSUdBMVVkRXd\
FQi93UUlNQVlCQWY4Q0FRRXdEZ1lEVlIwUEFRSC9CQVFEQWdJRU1CMEdBMVVkRGdRV0J\
CVG9aSU16UWRzRC9qLytnWC83Y0JKdWNIL1htakFLQmdncWhrak9QUVFEQWdOSkFEQkd\
BaUVBdHhRMytJTEdCUEl0U2g0YjlXWGhYTnVocVNQNkgrYi9MQy9mVllEalE2b0NJUUR\
HMnVSQ0hsVnEzeWhCNThUWE1VYnpIOCtPbGhXVXZPbFJEM1ZFcURkY1F3PT0ifX0",
"signatures":[{
"protected":"eyJ4NWMiOlsiTUlJQmt6Q0NBVGlnQXdJQkFnSUdBV0ZCakNrWU1\
Bb0dDQ3FHU000OUJBTUNNRDB4Q3pBSkJnTlZCQVlUQWtGUk1SVXdFd1lEVlFRS0RBeEt\
hVzVuU21sdVowTnZjbkF4RnpBVkJnTlZCQU1NRGtwcGJtZEthVzVuVkdWemRFTkJNQjR\
YRFRFNE1ERXlPVEV3TlRJME1Gb1hEVEk0TURFeU9URXdOVEkwTUZvd1R6RUxNQWtHQTF\
VRUJoTUNRVkV4RlRBVEJnTlZCQW9NREVwcGJtZEthVzVuUTI5eWNERXBNQ2NHQTFVRUF\
3d2dTbWx1WjBwcGJtZERiM0p3SUZadmRXTm9aWElnVTJsbmJtbHVaeUJMWlhrd1dUQVR\
CZ2NxaGtqT1BRSUJCZ2dxaGtqT1BRTUJCd05DQUFTQzZiZUxBbWVxMVZ3NmlRclJzOFI\
wWlcrNGIxR1d5ZG1XczJHQU1GV3diaXRmMm5JWEgzT3FIS1Z1OHMyUnZpQkdOaXZPS0d\
CSEh0QmRpRkVaWnZiN294SXdFREFPQmdOVkhROEJBZjhFQkFNQ0I0QXdDZ1lJS29aSXp\
qMEVBd0lEU1FBd1JnSWhBSTRQWWJ4dHNzSFAyVkh4XC90elVvUVwvU3N5ZEwzMERRSU5\
FdGNOOW1DVFhQQWlFQXZJYjNvK0ZPM0JUbmNMRnNhSlpSQWtkN3pPdXNuXC9cL1pLT2F\
FS2JzVkRpVT0iXSwidHlwIjoidm91Y2hlci1qd3MranNvbiIsImFsZyI6IkVTMjU2In0\
",
"signature":"ShqW8uFRkuAXIzjAhB4bolMMndcY7GYq3Kbo94yvGtjCaxEX3Hp\
6QXZUTEJ_kulQ1G7DnaU4igDPdUGtcV9Lkw"},{
"protected":"eyJ4NWMiOlsiTUlJQjRqQ0NBWWlnQXdJQkFnSUdBWFk3MmJiWk1\
Bb0dDQ3FHU000OUJBTUNNRFV4RXpBUkJnTlZCQW9NQ2sxNVFuVnphVzVsYzNNeERUQUx\
CZ05WQkFjTUJGTnBkR1V4RHpBTkJnTlZCQU1NQmxSbGMzUkRRVEFlRncweU1ERXlNRGN\
3TmpFNE1USmFGdzB6TURFeU1EY3dOakU0TVRKYU1ENHhFekFSQmdOVkJBb01DazE1UW5\
WemFXNWxjM014RFRBTEJnTlZCQWNNQkZOcGRHVXhHREFXQmdOVkJBTU1EMFJ2YldGcGJ\
sSmxaMmx6ZEhKaGNqQlpNQk1HQnlxR1NNNDlBZ0VHQ0NxR1NNNDlBd0VIQTBJQUJCazE\
2S1wvaTc5b1JrSzVZYmVQZzhVU1I4XC91czFkUFVpWkhNdG9rU2RxS1c1Zm5Xc0JkK3F\
STDdXUmZmZVdreWdlYm9KZklsbHVyY2kyNXduaGlPVkNHamV6QjVNQjBHQTFVZEpRUVd\
NQlFHQ0NzR0FRVUZCd01CQmdnckJnRUZCUWNESERBT0JnTlZIUThCQWY4RUJBTUNCNEF\
3U0FZRFZSMFJCRUV3UDRJZGNtVm5hWE4wY21GeUxYUmxjM1F1YzJsbGJXVnVjeTFpZEM\
1dVpYU0NIbkpsWjJsemRISmhjaTEwWlhOME5pNXphV1Z0Wlc1ekxXSjBMbTVsZERBS0J\
nZ3Foa2pPUFFRREFnTklBREJGQWlCeGxkQmhacTBFdjVKTDJQcldDdHlTNmhEWVcxeUN\
PXC9SYXVicEM3TWFJRGdJaEFMU0piZ0xuZ2hiYkFnMGRjV0ZVVm9cL2dHTjBcL2p3ekp\
aMFNsMmg0eElYazEiXSwidHlwIjoidm91Y2hlci1qd3MranNvbiIsImFsZyI6IkVTMjU\
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2In0",
"signature":"N4oXV48V6umsHMKkhdSSmJYFtVb6agjD32uXpIlGx6qVE7Dh0-b\
qhRRyjnxp80IV_Fy1RAOXIIzs3Q8CnMgBgg"
}]
}
Figure 28: Example Voucher-Response from MASA, with additional
Registrar signature
Appendix B. HTTP-over-TLS operations between Registrar-Agent and Pledge
The use of HTTP-over-TLS between Registrar-Agent and pledge has been
identified as an optional mechanism.
Provided that the key-agreement in the underlying TLS protocol
connection can be properly authenticated, the use of TLS provides
privacy for the voucher and enrollment operations between the pledge
and the Registrar-Agent. The authenticity of the onboarding and
enrollment is not dependant upon the security of the TLS connection.
The use of HTTP-over-TLS is not mandated by this document for a
number of reasons:
1. A certificate is generally required in order to do TLS. While
there are other modes of authentication including PSK, various
EAP methods and raw public key, they do no help as there is no
previous relationship between the Registrar-Agent.
2. The pledge can use it's IDevID certificate to authenticate
itself, but [RFC6125] DNS-ID methods do not apply as the pledge
does not have a FQDN. Instead a new mechanism is required, which
authenticates the X520SerialNumber DN attribute which must be
present in every IDevID.
If the Registrar-Agent has a preconfigured list of which product-
serial-number(s), from which manufacturers it expects to see, then it
can attempt to match this pledge against a list of potential devices.
In many cases only the list of manufacturers is known ahead of time,
so at most the Registrar-Agent can show the X520SerialNumber to the
(human) operator who may then attempt to confirm that they are
standing in front of a device with that product-serial-number. The
use of scannable QRcodes may help automate this in some cases.
1. The CA used to sign the IDevID will be a manufacturer private PKI
as described in [I-D.irtf-t2trg-taxonomy-manufacturer-anchors],
Section 4.1. The anchors for this PKI will never be part of the
public WebPKI anchors which are distributed with most smartphone
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operating systems. A Registrar-Agent application will need to
use different APIs in order to initiate an HTTPS connection
without performing WebPKI verification. The application will
then have to do it's own certificate chain verification against a
store of manufacturer trust anchors. In the Android ecosystem
this involved use of a customer TrustManager: many application
developers do not create these correctly, and there is
significant push to remove this option as it has repeatedly
resulted in security failures. See [androidtrustfail]
2. The use of the Host: (or :authority in HTTP/2) is explained in
[RFC9110], Section 7.2. This header is mandatory, and so a
compliant HTTPS client is going to insert it. But, the contents
of this header will at best be an IP address that came from the
discovery process. The pledge MUST therefore ignore the Host:
header when it processes requests, and the pledge MUST NOT do any
kind of name-base virtual hosting using the IP address/port
combination. Note that there is no requirement for the pledge to
operate it's BRSKI-PRM service on port 80 or port 443, so if
there is no reason for name-based virtual hosting.
3. Note that an Extended Key Usage (EKU) for TLS WWW Server
authentication cannot be expected in the pledge's IDevID
certificate. IDevID certificates are intended to be widely
useable and EKU does not support that use.
Appendix C. History of Changes [RFC Editor: please delete]
Proof of Concept Code available
From IETF draft 10 -> IETF draft 11:
* issue #79, clarified that BRSKI discovery in the context of BRSKI-
PRM is not needed in Section 5.6.1.
* issue #103, removed step 6 in verification handling for the
wrapped CA certificate provisioning as only applicable after
enrollment Section 6.3.3
* issue #128: included notation of nomadic operation of the
Registrar-Agent in Section 5, including proposed text from PR #131
* issue #130, introduced DNS service discovery name for brski_pledge
to enable discovery by the Registrar-Agent in Section 8
* removed unused reference RFC 5280
* removed site terminology
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* deleted duplicated text in Section 5.5
* clarified registrar discovery and relation to BRSKI-Discovery in
Section 5.6.1
* clarified discovery of pledges by the Registrar-Agent in
Section 5.6.2, deleted reference to GRASP as handled in BRSKI-
Discovery
* addressed comments from SECDIR early review
From IETF draft 09 -> IETF draft 10:
* issue #79, clarified discovery in the context of BRSKI-PRM and
included information about future discovery enhancements in a
separate draft in Section 5.6.1.
* issue #93, included information about conflict resolution in mDNS
and GRASP in Section 5.6.2
* issue #103, included verification handling for the wrapped CA
certificate provisioning in Section 6.3.3
* issue #106, included additional text to elaborate more the
registrar status handling in Section 6.3.6
* issue #116, enhanced DoS description in Section 10.1
* issue #120, included statement regarding pledge host header
processing in Section 5.5
* issue #122, availability of product-serial-number information on
registrar agent clarified in Section 6.1
* issue #123, Clarified usage of alternative voucher formats in
Section 6.2.3
* issue #124, determination of pinned domain certificate done as in
RFC 8995 included in Section 6.2.4
* issue #125, remove strength comparison of voucher assertions in
Section 5.4 and Section 6
* issue #130, aligned the usage of site and domain throughout the
document
* changed naming of registrar certificate from LDevID(RegAgt) to EE
(RegAgt) certificate throughout the document
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* change x5b to x5bag according to [RFC9360]
* updated JSON examples -> "signature": BASE64URL(JWS Signature)
From IETF draft 08 -> IETF draft 09:
* issue #80, enhanced Section 5.6.2 with clarification on the
product-serial-number and the inclusion of GRASP
* issue #81, enhanced introduction with motivation for
agent_signed_data
* issue #82, included optional TLS protection of the communication
link between Registrar-Agent and pledge in the introduction
Section 4, and Section 6.1
* issue #83, enhanced Section 6.1.4 and Section 6.2.6 with note to
re-enrollment
* issue #87, clarified available information at the Registrar-Agent
in Section 6.1
* issue #88, clarified, that the PVR in Section 6.1.2 and PER in
Section 6.1.4 may contain the certificate chain. If not contained
it MUST be available at the registrar.
* issue #91, clarified that a separate HTTP connection may also be
used to provide the PER in Section 6.2.6
* resolved remaining editorial issues discovered after WGLC
(responded to on the mailing list in Reply 1 and Reply 2)
resulting in more consistent descriptions
* issue #92: kept separate endpoint for wrapped CSR on registrar
Section 6.2.7
* issue #94: clarified terminology (possess vs. obtained)
* issue #95: clarified optional IDevID CA certificates on Registrar-
Agent Section 6.3
* issue #96: updated Figure 16 to correct to just one CA certificate
provisioning
* issue #97: deleted format explanation in Section 6.3 as it may be
misleading
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* issue #99: motivated verification of second signature on voucher
in Section 6.3
* issue #100: included negative example in Figure 17
* issue #101: included handling if Section 6.3.2 voucher telemetry
information has not been received by the Registrar-Agent
* issue #102: relaxed requirements for CA certs provisioning in
Section 6.3.3
* issue #105: included negative example in Figure 18
* issue #107: included example for certificate revocation in
Section 6.3.6
* issue #108: renamed heading to Pledge-Status Request of
Section 6.4.1
* issue #111: included pledge-status response processing for
authenticated requests in Section 6.4.2
* issue #112: added "Example key word in pledge-status response in
Figure 24
* issue #113: enhanced description of status reply for "factory-
default" in Section 6.4.2
* issue #114: Consideration of optional TLS usage in Privacy
Considerations
* issue #115: Consideration of optional TLS usage in Privacy
Considerations to protect potentially privacy related information
in the bootstrapping like status information, etc.
* issue #116: Enhanced DoS description and mitigation options in
security consideration section
* updated references
From IETF draft 07 -> IETF draft 08:
* resolved editorial issues discovered after WGLC (still open issues
remaining)
* resolved first comments from the Shepherd review as discussed in
PR #85 on the ANIMA github
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From IETF draft 06 -> IETF draft 07:
* WGLC resulted in a removal of the voucher enhancements completely
from this document to RFC 8366bis, containing all enhancements and
augmentations of the voucher, including the voucher-request as
well as the tree diagrams
* smaller editorial corrections
From IETF draft 05 -> IETF draft 06:
* Update of list of reviewers
* Issue #67, shortened the pledge endpoints to prepare for
constraint deployments
* Included table for new endpoints on the registrar in the overview
of the Registrar-Agent
* addressed review comments from SECDIR early review (terminology
clarifications, editorial improvements)
* addressed review comments from IOTDIR early review (terminology
clarifications, editorial improvements)
From IETF draft 04 -> IETF draft 05:
* Restructured document to have a distinct section for the object
flow and handling and shortened introduction, issue #72
* Added security considerations for using mDNS without a specific
product-serial-number, issue #75
* Clarified pledge-status responses are cumulative, issue #73
* Removed agent-sign-cert from trigger data to save bandwidth and
remove complexity through options, issue #70
* Changed terminology for LDevID(Reg) certificate to registrar
LDevID certificate, as it does not need to be an LDevID, issue #66
* Added new protected header parameter (created-on) in PER to
support freshness validation, issue #63
* Removed reference to CAB Forum as not needed for BRSKI-PRM
specifically, issue #65
* Enhanced error codes in section 5.5.1, issue #39, #64
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* Enhanced security considerations and privacy considerations, issue
#59
* Issue #50 addressed by referring to the utilized enrollment
protocol
* Issue #47 MASA verification of LDevID(RegAgt) to the same
registrar LDevID certificate domain CA
* Reworked terminology of "enrollment object", "certification
object", "enrollment request object", etc., issue #27
* Reworked all message representations to align with encoding
* Added explanation of MASA requiring domain CA cert in section
5.5.1 and section 5.5.2, issue #36
* Defined new endpoint for pledge bootstrapping status inquiry,
issue #35 in section Section 6.4, IANA considerations and section
Section 5.5
* Included examples for several objects in section Appendix A
including message example sizes, issue #33
* PoP for private key to registrar certificate included as
mandatory, issues #32 and #49
* Issue #31, clarified that combined pledge may act as client/server
for further (re)enrollment
* Issue #42, clarified that Registrar needs to verify the status
responses with and ensure that they match the audit log response
from the MASA, otherwise it needs drop the pledge and revoke the
certificate
* Issue #43, clarified that the pledge shall use the create time
from the trigger message if the time has not been synchronized,
yet.
* Several editorial changes and enhancements to increasing
readability.
From IETF draft 03 -> IETF draft 04:
* In deep Review by Esko Dijk lead to issues #22-#61, which are bein
stepwise integrated
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* Simplified YANG definition by augmenting the voucher-request from
RFC 8995 instead of redefining it.
* Added explanation for terminology "endpoint" used in this
document, issue #16
* Added clarification that Registrar-Agent may collect PVR or PER or
both in one run, issue #17
* Added a statement that nonceless voucher may be accepted, issue
#18
* Simplified structure in section Section 3.1, issue #19
* Removed join proxy in Figure 1 and added explanatory text, issue
#20
* Added description of pledge-CAcerts endpoint plus further handling
of providing a wrapped CA certs response to the pledge in section
Section 6.3; also added new required registrar endpoint (section
Section 6.2 and IANA considerations) for the registrar to provide
a wrapped CA certs response, issue #21
* utilized defined abbreviations in the document consistently, issue
#22
* Reworked text on discovery according to issue #23 to clarify scope
and handling
* Added several clarifications based on review comments
From IETF draft 02 -> IETF draft 03:
* Updated examples to state "base64encodedvalue==" for x5c
occurrences
* Include link to SVG graphic as general overview
* Restructuring of section 5 to flatten hierarchy
* Enhanced requirements and motivation in Section 4
* Several editorial improvements based on review comments
From IETF draft 01 -> IETF draft 02:
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* Issue #15 included additional signature on voucher from registrar
in section Section 6.2 and section Section 5.4 The verification of
multiple signatures is described in section Section 6.3
* Included representation for General JWS JSON Serialization for
examples
* Included error responses from pledge if it is not able to create a
pledge voucher-request or an enrollment request in section
Section 6.1
* Removed open issue regarding handling of multiple CSRs and
enrollment responses during the bootstrapping as the initial
target it the provisioning of a generic LDevID certificate. The
defined endpoint on the pledge may also be used for management of
further certificates.
From IETF draft 00 -> IETF draft 01:
* Issue #15 lead to the inclusion of an option for an additional
signature of the registrar on the voucher received from the MASA
before forwarding to the Registrar-Agent to support verification
of POP of the registrars private key in section Section 6.2 and
Section 6.3.
* Based on issue #11, a new endpoint was defined for the registrar
to enable delivery of the wrapped enrollment request from the
pledge (in contrast to plain PKCS#10 in simple enroll).
* Decision on issue #8 to not provide an additional signature on the
enrollment-response object by the registrar. As the enrollment
response will only contain the generic LDevID certificate. This
credential builds the base for further configuration outside the
initial enrollment.
* Decision on issue #7 to not support multiple CSRs during the
bootstrapping, as based on the generic LDevID certificate the
pledge may enroll for further certificates.
* Closed open issue #5 regarding verification of ietf-ztp-types
usage as verified via a proof-of-concept in section
{#exchanges_uc2_1}.
* Housekeeping: Removed already addressed open issues stated in the
draft directly.
* Reworked text in from introduction to section pledge-responder-
mode
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* Fixed "serial-number" encoding in PVR/RVR
* Added prior-signed-voucher-request in the parameter description of
the registrar-voucher-request in Section 6.2.
* Note added in Section 6.2 if sub-CAs are used, that the
corresponding information is to be provided to the MASA.
* Inclusion of limitation section (pledge sleeps and needs to be
waked up. Pledge is awake but Registrar-Agent is not available)
(Issue #10).
* Assertion-type aligned with voucher in RFC8366bis, deleted related
open issues. (Issue #4)
* Included table for endpoints in Section 5.5 for better
readability.
* Included registrar authorization check for Registrar-Agent during
TLS handshake in section Section 6.2. Also enhanced figure
Figure 11 with the authorization step on TLS level.
* Enhanced description of registrar authorization check for
Registrar-Agent based on the agent-signed-data in section
Section 6.2. Also enhanced figure Figure 11 with the
authorization step on pledge-voucher-request level.
* Changed agent-signed-cert to an array to allow for providing
further certificate information like the issuing CA cert for the
LDevID(RegAgt) certificate in case the registrar and the
Registrar-Agent have different issuing CAs in Figure 11 (issue
#12). This also required changes in the YANG module in
[I-D.ietf-anima-rfc8366bis]
* Addressed YANG warning (issue #1)
* Inclusion of examples for a trigger to create a pledge-voucher-
request and an enrollment-request.
From IETF draft-ietf-anima-brski-async-enroll-03 -> IETF anima-brski-
prm-00:
* Moved UC2 related parts defining the pledge in responder mode from
draft-ietf-anima-brski-async-enroll-03 to this document This
required changes and adaptations in several sections to remove the
description and references to UC1.
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* Addressed feedback for voucher-request enhancements from YANG
doctor early review in Section 7.1 as well as in the security
considerations (formerly named ietf-async-voucher-request).
* Renamed ietf-async-voucher-request to IETF-voucher-request-prm to
to allow better listing of voucher related extensions; aligned
with constraint voucher (#20)
* Utilized ietf-voucher-request-async instead of ietf-voucher-
request in voucher exchanges to utilize the enhanced voucher-
request.
* Included changes from draft-ietf-netconf-sztp-csr-06 regarding the
YANG definition of csr-types into the enrollment request exchange.
From IETF draft 02 -> IETF draft 03:
* Housekeeping, deleted open issue regarding YANG voucher-request in
Section 6.1 as voucher-request was enhanced with additional leaf.
* Included open issues in YANG model in Section 5 regarding
assertion value agent-proximity and csr encapsulation using SZTP
sub module).
From IETF draft 01 -> IETF draft 02:
* Defined call flow and objects for interactions in UC2. Object
format based on draft for JOSE signed voucher artifacts and
aligned the remaining objects with this approach in Section 6.
* Terminology change: issue #2 pledge-agent -> Registrar-Agent to
better underline Registrar-Agent relation.
* Terminology change: issue #3 PULL/PUSH -> pledge-initiator-mode
and pledge-responder-mode to better address the pledge operation.
* Communication approach between pledge and Registrar-Agent changed
by removing TLS-PSK (former section TLS establishment) and
associated references to other drafts in favor of relying on
higher layer exchange of signed data objects. These data objects
are included also in the pledge-voucher-request and lead to an
extension of the YANG module for the voucher-request (issue #12).
* Details on trust relationship between Registrar-Agent and
registrar (issue #4, #5, #9) included in Section 5.
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* Recommendation regarding short-lived certificates for Registrar-
Agent authentication towards registrar (issue #7) in the security
considerations.
* Introduction of reference to Registrar-Agent signing certificate
using SKID in Registrar-Agent signed data (issue #37).
* Enhanced objects in exchanges between pledge and Registrar-Agent
to allow the registrar to verify agent-proximity to the pledge
(issue #1) in Section 6.
* Details on trust relationship between Registrar-Agent and pledge
(issue #5) included in Section 5.
* Split of use case 2 call flow into sub sections in Section 6.
From IETF draft 00 -> IETF draft 01:
* Update of scope in Section 3.1 to include in which the pledge acts
as a server. This is one main motivation for use case 2.
* Rework of use case 2 in Section 5 to consider the transport
between the pledge and the pledge-agent. Addressed is the TLS
channel establishment between the pledge-agent and the pledge as
well as the endpoint definition on the pledge.
* First description of exchanged object types (needs more work)
* Clarification in discovery options for enrollment endpoints at the
domain registrar based on well-known endpoints do not result in
additional /.well-known URIs. Update of the illustrative example.
Note that the change to /brski for the voucher related endpoints
has been taken over in the BRSKI main document.
* Updated references.
* Included Thomas Werner as additional author for the document.
From individual version 03 -> IETF draft 00:
* Inclusion of discovery options of enrollment endpoints at the
domain registrar based on well-known endpoints in new section as
replacement of section 5.1.3 in the individual draft. This is
intended to support both use cases in the document. An
illustrative example is provided.
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* Missing details provided for the description and call flow in
pledge-agent use case Section 5, e.g. to accommodate distribution
of CA certificates.
* Updated CMP example in to use lightweight CMP instead of CMP, as
the draft already provides the necessary /.well-known endpoints.
* Requirements discussion moved to separate section in Section 4.
Shortened description of proof of identity binding and mapping to
existing protocols.
* Removal of copied call flows for voucher exchange and registrar
discovery flow from [RFC8995] in UC1 to avoid doubling or text or
inconsistencies.
* Reworked abstract and introduction to be more crisp regarding the
targeted solution. Several structural changes in the document to
have a better distinction between requirements, use case
description, and solution description as separate sections.
History moved to appendix.
From individual version 02 -> 03:
* Update of terminology from self-contained to authenticated self-
contained object to be consistent in the wording and to underline
the protection of the object with an existing credential. Note
that the naming of this object may be discussed. An alternative
name may be attestation object.
* Simplification of the architecture approach for the initial use
case having an offsite PKI.
* Introduction of a new use case utilizing authenticated self-
contain objects to onboard a pledge using a commissioning tool
containing a pledge-agent. This requires additional changes in
the BRSKI call flow sequence and led to changes in the
introduction, the application example,and also in the related
BRSKI-PRM call flow.
From individual version 01 -> 02:
* Update of introduction text to clearly relate to the usage of
IDevID and LDevID.
* Update of description of architecture elements and changes to
BRSKI in Section 5.
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* Enhanced consideration of existing enrollment protocols in the
context of mapping the requirements to existing solutions in
Section 4.
From individual version 00 -> 01:
* Update of examples, specifically for building automation as well
as two new application use cases in Section 3.1.
* Deletion of asynchronous interaction with MASA to not complicate
the use case. Note that the voucher exchange can already be
handled in an asynchronous manner and is therefore not considered
further. This resulted in removal of the alternative path the
MASA in Figure 1 and the associated description in Section 5.
* Enhancement of description of architecture elements and changes to
BRSKI in Section 5.
* Consideration of existing enrollment protocols in the context of
mapping the requirements to existing solutions in Section 4.
* New section starting with the mapping to existing enrollment
protocols by collecting boundary conditions.
Contributors
Esko Dijk
IoTconsultancy.nl
Email: esko.dijk@iotconsultancy.nl
Toerless Eckert
Futurewei
Email: tte@cs.fau.de
Matthias Kovatsch
Email: ietf@kovatsch.net
Authors' Addresses
Steffen Fries
Siemens AG
Otto-Hahn-Ring 6
81739 Munich
Germany
Email: steffen.fries@siemens.com
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URI: https://www.siemens.com/
Thomas Werner
Siemens AG
Otto-Hahn-Ring 6
81739 Munich
Germany
Email: thomas-werner@siemens.com
URI: https://www.siemens.com/
Eliot Lear
Cisco Systems
Richtistrasse 7
CH-8304 Wallisellen
Switzerland
Phone: +41 44 878 9200
Email: lear@cisco.com
Michael C. Richardson
Sandelman Software Works
Email: mcr+ietf@sandelman.ca
URI: http://www.sandelman.ca/
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