draft-ietf-anima-bootstrapping-keyinfra-03.txt   draft-ietf-anima-bootstrapping-keyinfra-04.txt 
ANIMA WG M. Pritikin ANIMA WG M. Pritikin
Internet-Draft Cisco Internet-Draft Cisco
Intended status: Informational M. Richardson Intended status: Informational M. Richardson
Expires: January 1, 2017 SSW Expires: May 4, 2017 SSW
M. Behringer M. Behringer
S. Bjarnason S. Bjarnason
Cisco Cisco
June 30, 2016 K. Watsen
Juniper Networks
October 31, 2016
Bootstrapping Remote Secure Key Infrastructures (BRSKI) Bootstrapping Remote Secure Key Infrastructures (BRSKI)
draft-ietf-anima-bootstrapping-keyinfra-03 draft-ietf-anima-bootstrapping-keyinfra-04
Abstract Abstract
This document specifies automated bootstrapping of a remote secure This document specifies automated bootstrapping of a remote secure
key infrastructure (BRSKI) using vendor installed IEEE 802.1AR key infrastructure (BRSKI) using vendor installed X.509 certificate,
manufacturing installed certificates, in combination with a vendor in combination with a vendor authorized service on the Internet.
based service on the Internet. Before being authenticated, a new Bootstrapping a new device can occur using a routable address and a
device has only link-local connectivity, and does not require a cloud service, or using only link-local connectivity, or on limited/
routable address. When a vendor provides an Internet based service disconnected networks. Support for lower security models, including
devices can be redirected to a local service. In limited/ devices with minimal identity, is described for legacy reasons but
disconnected networks or legacy environments we describe a variety of not encouraged. Bootstrapping is complete when the cryptographic
options that allow bootstrapping to proceed. Support for lower identity of the new key infrastructure is successfully deployed to
security models, including devices with minimal identity, is the device but the established secure connection can be used to
described for legacy reasons but not encouraged. deploy a locally issued certificate to the device as well.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 1, 2017. This Internet-Draft will expire on May 4, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
1.2. Scope of solution . . . . . . . . . . . . . . . . . . . . 6 1.2. Scope of solution . . . . . . . . . . . . . . . . . . . . 7
1.3. Trust bootstrap . . . . . . . . . . . . . . . . . . . . . 7 1.3. Trust bootstrap . . . . . . . . . . . . . . . . . . . . . 8
2. Architectural Overview . . . . . . . . . . . . . . . . . . . 7 2. Architectural Overview . . . . . . . . . . . . . . . . . . . 8
3. Functional Overview . . . . . . . . . . . . . . . . . . . . . 9 3. Functional Overview . . . . . . . . . . . . . . . . . . . . . 10
3.1. Behavior of a New Entity . . . . . . . . . . . . . . . . 11 3.1. Behavior of a Pledge . . . . . . . . . . . . . . . . . . 11
3.1.1. Discovery . . . . . . . . . . . . . . . . . . . . . . 13 3.1.1. Discovery . . . . . . . . . . . . . . . . . . . . . . 13
3.1.2. Identity . . . . . . . . . . . . . . . . . . . . . . 14 3.1.2. Identity . . . . . . . . . . . . . . . . . . . . . . 14
3.1.3. Request Join . . . . . . . . . . . . . . . . . . . . 15 3.1.3. Request Join . . . . . . . . . . . . . . . . . . . . 15
3.1.4. Imprint . . . . . . . . . . . . . . . . . . . . . . . 15 3.1.4. Imprint . . . . . . . . . . . . . . . . . . . . . . . 15
3.1.5. Lack of realtime clock . . . . . . . . . . . . . . . 16 3.1.5. Lack of realtime clock . . . . . . . . . . . . . . . 16
3.1.6. Enrollment . . . . . . . . . . . . . . . . . . . . . 17 3.1.6. Enrollment . . . . . . . . . . . . . . . . . . . . . 17
3.1.7. Being Managed . . . . . . . . . . . . . . . . . . . . 18 3.1.7. Being Managed . . . . . . . . . . . . . . . . . . . . 18
3.2. Behavior of a Proxy . . . . . . . . . . . . . . . . . . . 18 3.2. Behavior of a Proxy . . . . . . . . . . . . . . . . . . . 18
3.2.1. CoAP connection to Registrar . . . . . . . . . . . . 19 3.2.1. CoAP connection to Registrar . . . . . . . . . . . . 19
3.2.2. HTTPS proxy connection to Registrar . . . . . . . . . 19 3.2.2. HTTPS proxy connection to Registrar . . . . . . . . . 19
3.3. Behavior of the Registrar (Bootstrap Server) . . . . . . 20 3.3. Behavior of the Registrar . . . . . . . . . . . . . . . . 20
3.3.1. Entity Authentication . . . . . . . . . . . . . . . . 21 3.3.1. Pledge Authentication . . . . . . . . . . . . . . . . 21
3.3.2. Entity Authorization . . . . . . . . . . . . . . . . 21 3.3.2. Pledge Authorization . . . . . . . . . . . . . . . . 22
3.3.3. Claiming the New Entity . . . . . . . . . . . . . . . 22 3.3.3. Claiming the New Entity . . . . . . . . . . . . . . . 23
3.3.4. Log Verification . . . . . . . . . . . . . . . . . . 23 3.3.4. Log Verification . . . . . . . . . . . . . . . . . . 23
3.4. Behavior of the MASA Service . . . . . . . . . . . . . . 24 3.4. Behavior of the MASA Service . . . . . . . . . . . . . . 24
3.4.1. Issue Authorization Token and Log the event . . . . . 24 3.4.1. Issue Audit Voucher and Log the event . . . . . . . . 24
3.4.2. Retrieve Audit Entries from Log . . . . . . . . . . . 24 3.4.2. Retrieve Audit Entries from Log . . . . . . . . . . . 24
3.5. Leveraging the new key infrastructure / next steps . . . 24 3.5. Leveraging the new key infrastructure / next steps . . . 25
3.5.1. Network boundaries . . . . . . . . . . . . . . . . . 25 3.5.1. Network boundaries . . . . . . . . . . . . . . . . . 25
3.6. Interactions with Network Access Control . . . . . . . . 25 3.6. Interactions with Network Access Control . . . . . . . . 25
4. Domain Operator Activities . . . . . . . . . . . . . . . . . 25 4. Domain Operator Activities . . . . . . . . . . . . . . . . . 25
4.1. Instantiating the Domain Certification Authority . . . . 25 4.1. Instantiating the Domain Certification Authority . . . . 26
4.2. Instantiating the Registrar . . . . . . . . . . . . . . . 25 4.2. Instantiating the Registrar . . . . . . . . . . . . . . . 26
4.3. Accepting New Entities . . . . . . . . . . . . . . . . . 26 4.3. Accepting New Entities . . . . . . . . . . . . . . . . . 26
4.4. Automatic Enrollment of Devices . . . . . . . . . . . . . 27 4.4. Automatic Enrollment of Devices . . . . . . . . . . . . . 27
4.5. Secure Network Operations . . . . . . . . . . . . . . . . 27 4.5. Secure Network Operations . . . . . . . . . . . . . . . . 27
5. Protocol Details . . . . . . . . . . . . . . . . . . . . . . 27 5. Protocol Details . . . . . . . . . . . . . . . . . . . . . . 28
5.1. Request Audit Token from the Registrar . . . . . . . . . 30 5.1. Request Voucher from the Registrar . . . . . . . . . . . 30
5.2. Request Audit Token from MASA . . . . . . . . . . . . . . 32 5.2. Request Voucher from MASA . . . . . . . . . . . . . . . . 32
5.3. Audit Token Response . . . . . . . . . . . . . . . . . . 33 5.3. Audit Voucher Response . . . . . . . . . . . . . . . . . 33
5.3.1. Completing authentication of Provisional TLS 5.3.1. Completing authentication of Provisional TLS
connection . . . . . . . . . . . . . . . . . . . . . 34 connection . . . . . . . . . . . . . . . . . . . . . 34
5.4. Audit Token Status Telemetry . . . . . . . . . . . . . . 35 5.4. Voucher Status Telemetry . . . . . . . . . . . . . . . . 35
5.5. MASA authorization log Request . . . . . . . . . . . . . 36 5.5. MASA authorization log Request . . . . . . . . . . . . . 36
5.6. MASA authorization log Response . . . . . . . . . . . . . 36 5.6. MASA authorization log Response . . . . . . . . . . . . . 36
5.7. EST Integration for PKI bootstrapping . . . . . . . . . . 37 5.7. EST Integration for PKI bootstrapping . . . . . . . . . . 37
5.7.1. EST Distribution of CA Certificates . . . . . . . . . 37 5.7.1. EST Distribution of CA Certificates . . . . . . . . . 37
5.7.2. EST CSR Attributes . . . . . . . . . . . . . . . . . 38 5.7.2. EST CSR Attributes . . . . . . . . . . . . . . . . . 37
5.7.3. EST Client Certificate Request . . . . . . . . . . . 38 5.7.3. EST Client Certificate Request . . . . . . . . . . . 38
5.7.4. Enrollment Status Telemetry . . . . . . . . . . . . . 38 5.7.4. Enrollment Status Telemetry . . . . . . . . . . . . . 38
5.7.5. EST over CoAP . . . . . . . . . . . . . . . . . . . . 39 5.7.5. EST over CoAP . . . . . . . . . . . . . . . . . . . . 39
6. Reduced security operational modes . . . . . . . . . . . . . 40 6. Reduced security operational modes . . . . . . . . . . . . . 39
6.1. Trust Model . . . . . . . . . . . . . . . . . . . . . . . 40 6.1. Trust Model . . . . . . . . . . . . . . . . . . . . . . . 40
6.2. New Entity security reductions . . . . . . . . . . . . . 41 6.2. New Entity security reductions . . . . . . . . . . . . . 40
6.3. Registrar security reductions . . . . . . . . . . . . . . 41 6.3. Registrar security reductions . . . . . . . . . . . . . . 41
6.4. MASA security reductions . . . . . . . . . . . . . . . . 42 6.4. MASA security reductions . . . . . . . . . . . . . . . . 42
7. Security Considerations . . . . . . . . . . . . . . . . . . . 42 7. Security Considerations . . . . . . . . . . . . . . . . . . . 42
7.1. Security concerns with discovery process . . . . . . . . 44
7.1.1. Discovery of Registrar by Proxy . . . . . . . . . . . 44
7.1.2. Discovery of Proxy by New Entity . . . . . . . . . . 44
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 44 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 44
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 44 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 44
9.1. Normative References . . . . . . . . . . . . . . . . . . 44 9.1. Normative References . . . . . . . . . . . . . . . . . . 44
9.2. Informative References . . . . . . . . . . . . . . . . . 45 9.2. Informative References . . . . . . . . . . . . . . . . . 46
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 46 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 47
1. Introduction 1. Introduction
To literally "pull yourself up by the bootstraps" is an impossible To literally "pull yourself up by the bootstraps" is an impossible
action. Similarly the secure establishment of a key infrastructure action. Similarly the secure establishment of a key infrastructure
without external help is also an impossibility. Today it is accepted without external help is also an impossibility. Today it is accepted
that the initial connections between nodes are insecure, until key that the initial connections between nodes are insecure, until key
distribution is complete, or that domain-specific keying material is distribution is complete, or that domain-specific keying material is
pre-provisioned on each new device in a costly and non-scalable pre-provisioned on each new device in a costly and non-scalable
manner. This document describes a zero-touch approach to manner. This document describes a zero-touch approach to
bootstrapping an entity by securing the initial distribution of key bootstrapping an entity by securing the initial distribution of key
material using third-party generic keying material, such as a material using third-party issued X.509 certificates and
manufacturer installed IEEE 802.1AR certificate [IDevID], and a cryptographically signed "vouchers" issued by a new form of cloud
corresponding third-party service on the Internet. service.
The two sides of an association being bootstrapped authenticate each The two sides of an association being bootstrapped authenticate each
other and then determine appropriate authorization. This process is other and then determine appropriate authorization. This process is
described as four distinct steps between the existing domain and the described as four distinct steps between the existing domain and the
new entity being added: device, or "pledge", being added:
o New entity authentication: "Who is this? What is its identity?" o Pledge authentication: "Who is this? What is its identity?"
o New entity authorization: "Is it mine? Do I want it? What are o Pledge authorization: "Is it mine? Do I want it? What are the
the chances it has been compromised?" chances it has been compromised?"
o Domain authentication: "What is this domain's claimed identity?" o Domain authentication: "What is this domain's claimed identity?"
o Domain authorization: "Should I join it?" o Domain authorization: "Should I join it?"
A precise answer to these questions can not be obtained without A precise answer to these questions can not be obtained without
leveraging some established key infrastructure(s). A complexity that leveraging an established key infrastructure(s). The pledge's
this protocol deals with are dealing with devices from a variety of decisions are made according to verified communication with a trusted
vendors, and a network infrastructure (the domain) that is operated third-party. The domain's decisions are made by comparing the
by parties that do not have any priviledged relationship with the pledge's authenticated identity against domain information such as a
device vendors. The domain's decisions are based on the new entity's configured list of purchased devices supplimented by information
authenticated identity, as established by verification of previously provided by a trusted third-party. The third-party is not required
installed credentials such as a manufacturer installed IEEE 802.1AR to provide sales channel ownership tracking nor is it required to
certificate, and verified back-end information such as a configured authenticate the domain.
list of purchased devices or communication with a (unidirectionally)
trusted third-party. The new entity's decisions are made according
to verified communication with a trusted third-party or in a strictly
auditable fashion.
Optimal security is achieved with IEEE 802.1AR certificates on each Optimal security is achieved with X.509 certificates on each Pledge,
new entity, accompanied by a third-party Internet based service for accompanied by a third-party (e.g., vendor, manufacturer or
verification. Bootstrapping concepts run to completion with less integrator) Internet based service for verification. Bootstrapping
requirements, but are then less secure. A domain can choose to concepts run to completion with less requirements, but are then less
accept lower levels of security when a trusted third-party is not secure. A domain can choose to accept lower levels of security when
available so that bootstrapping proceeds even at the risk of reduced a trusted third-party is not available so that bootstrapping proceeds
security. Only the domain can make these decisions based on even at the risk of reduced security. Only the domain can make these
administrative input and known behavior of the new entity. decisions based on administrative input and known behavior of the
pledge.
The result of bootstrapping is that a domain specific key The result of bootstrapping is that a domain specific key
infrastructure is deployed. Since IEEE 802.1AR PKI certificates are infrastructure is deployed. Since X.509 PKI certificates are used
used for identifying the new entity, and the public key of the domain for identifying the pledge, and the public key of the domain identity
identity is leveraged during communications with an Internet based is leveraged during communications with an Internet based service,
service, which is itself authenticated using HTTPS, bootstrapping of which is itself authenticated using HTTPS, bootstrapping of a domain
a domain specific Public Key Infrastructure (PKI) is described. specific Public Key Infrastructure (PKI) is described. Sufficient
Sufficient agility to support bootstrapping alternative key agility to support bootstrapping alternative key infrastructures
infrastructures (such as symmetric key solutions) is considered (such as symmetric key solutions) is considered although no such
although no such alternate key infrastructure is described. alternate key infrastructure is described.
1.1. Terminology 1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in
[RFC2119]. [RFC2119].
The following terms are defined for clarity: The following terms are defined for clarity:
DomainID: The domain identity is the 160-bit SHA-1 hash of the BIT DomainID: The domain identity is the 160-bit SHA-1 hash of the BIT
STRING of the subjectPublicKey of the domain trust anchor that is STRING of the subjectPublicKey of the domain trust anchor that is
stored by the Domain CA. This is consistent with the RFC5280 stored by the Domain CA. This is consistent with the
Certification Authority subject key identifier of the Domain CA's Certification Authority subject key identifier (Section 4.2.1.2
self signed root certificate. (A string value bound to the Domain [RFC5280]) of the Domain CA's self signed root certificate. (A
CA's self signed root certificate subject and issuer fields is string value bound to the Domain CA's self signed root certificate
often colloquially used as a humanized identity value but during subject and issuer fields is often colloquially used as a
protocol discussions the more exact term as defined here is used). humanized identity value but during protocol discussions the more
exact term as defined here is used).
drop ship: The physical distribution of equipment containing the drop ship: The physical distribution of equipment containing the
"factory default" configuration to a final destination. In zero- "factory default" configuration to a final destination. In zero-
touch scenarios there is no staging or pre-configuration during touch scenarios there is no staging or pre-configuration during
drop-ship. drop-ship.
imprint: the process where a device obtains the cryptographic key imprint: The process where a device obtains the cryptographic key
material to identity and trust future interactions with a network. material to identify and trust future interactions with a network.
This term is taken from Konrad Lorenz's work in biology with new This term is taken from Konrad Lorenz's work in biology with new
ducklings: during a critical period, the duckling would assume ducklings: during a critical period, the duckling would assume
that anything that looks like a mother duck is in fact their that anything that looks like a mother duck is in fact their
mother. An equivalent for a device is to obtain the fingerprint mother. An equivalent for a device is to obtain the fingerprint
of the network's root certification authority certificate. A of the network's root certification authority certificate. A
device that imprints on an attacker suffers a similar fate to a device that imprints on an attacker suffers a similar fate to a
duckling that imprints on a hungry wolf. Securely imprinting is a duckling that imprints on a hungry wolf. Securely imprinting is a
primary focus of this document.[imprinting]. primary focus of this document.[imprinting]. The analogy to
Lorenz's work was first noted in [Stajano99theresurrecting].
enrollment: the process where a device presents key material to a enrollment: The process where a device presents key material to a
network and acquires a network specific identity. For example network and acquires a network specific identity. For example
when a certificate signing request is presented to a certification when a certificate signing request is presented to a certification
authority and a certificate is obtained in response. authority and a certificate is obtained in response.
pledge: the prospective device, which has the identity provided to Pledge: The prospective device, which has an identity installed by a
at the factory. Neither the device nor the network knows if the third-party (e.g., vendor, manufacturer or integrator).
device yet knows if this device belongs with this network. This
is definition 6, according to [pledge]
Audit Token: A signed token from the manufacturer authorized signing Voucher A signed statement from the MASA service that indicates to a
authority indicating that the bootstrapping event has been Pledge the cryptographic identity of the Registrar it should
successfully logged. This has been referred to as an trust. There are different types of vouchers depending on how
"authorization token" indicating that it authorizes bootstrapping that trust verified.
to proceed.
Ownership Voucher: A signed voucher from the vendor vouching that a Audit Voucher: A voucher from the MASA service that indicates that
specific domain "owns" the new entity as defined in the bootstrapping event has been successfully logged. The
[I-D.ietf-netconf-zerotouch]. Registrar is primarily responsible for verifying the logs and
ensuring domain network security.
Ownership Voucher: A voucher from the MASA service that indicates
the explicit owner identity. The MASA is primarily responsible
for tracking ownership using out-of-band sales channel integration
(the definition of which is out-of-scope of this document). It is
defined in [I-D.ietf-netconf-zerotouch].
Domain: The set of entities that trust a common key infrastructure
trust anchor. This includes the Proxy, Registrar, Domain
Certificate Authority, Management components and any existing
entity that is already a member of the domain.
Domain CA: The domain Certification Authority (CA) provides
certification functionalities to the domain. At a minimum it
provides certification functionalities to a Registrar and stores
the trust anchor that defines the domain. Optionally, it
certifies all elements.
Registrar: A representative of the domain that is configured,
perhaps autonomically, to decide whether a new device is allowed
to join the domain. The administrator of the domain interfaces
with a Registrar to control this process. Typically a Registrar
is "inside" its domain.
Proxy: A domain entity that helps the pledge join the domain. A
Proxy facilitates communication for devices that find themselves
in an environment where they are not provided connectivity until
after they are validated as members of the domain. The pledge is
unaware that they are communicating with a proxy rather than
directly with a Registrar.
MASA Service: A third-party Manufacturer Authorized Signing
Authority (MASA) service on the global Internet. The MASA
provides a repository for audit log information concerning privacy
protected bootstrapping events. It does not track ownership.
Ownership Tracker An Ownership Tracker service on the global
internet. The Ownership Tracker uses business processes to
accurately track ownership of all devices shipped against domains
that have purchased them. Although optional this component allows
vendors to provide additional value in cases where their sales and
distribution channels allow for accurately tracking of such
ownership.
IDevID An Initial Device Identity X.509 certificate installed by the
vendor on new equipment. The [IDevID] certificate format is the
primary example. In particular the X.509 certificate needs to
contain the device's serial number in a well known location in
order to perform white list operations and in order to extract it
for inclusion in messages to the MASA service. The subject
field's DN encoding MUST include the "serialNumber" attribute with
the device's unique serial number.
1.2. Scope of solution 1.2. Scope of solution
Questions have been posed as to whether this solution is suitable in Questions have been posed as to whether this solution is suitable in
general for Internet of Things (IoT) networks. In general the answer general for Internet of Things (IoT) networks. This depends on the
is no, but the terminology of [RFC7228] is best used to describe the capabilities of the devices in question. The terminology of
boundaries. [RFC7228] is best used to describe the boundaries.
The entire solution described in this document is aimed in general at The entire solution described in this document is aimed in general at
non-constrained (i.e. class 2+) devices operating on a non-Challenged non-constrained (i.e. class 2+) devices operating on a non-Challenged
network. The entire solution described here is not intended to be network. The entire solution described here is not intended to be
useable as-is by constrained devices operating on challenged networks useable as-is by constrained devices operating on challenged networks
(such as 802.15.4 LLNs). (such as 802.15.4 LLNs).
In many target applications, the systems involved are large router In many target applications, the systems involved are large router
platforms with multi-gigabit inter-connections, mounted in controlled platforms with multi-gigabit inter-connections, mounted in controlled
access data centers. But this solution is not exclusive to the access data centers. But this solution is not exclusive to the
skipping to change at page 6, line 32 skipping to change at page 7, line 41
hostile environments, such as ISP provided CPE devices which are hostile environments, such as ISP provided CPE devices which are
drop-shipped to the end user. The situation where an order is drop-shipped to the end user. The situation where an order is
fulfilled from distributed warehouse from a common stock and shipped fulfilled from distributed warehouse from a common stock and shipped
directly to the target location at the request of the domain owner is directly to the target location at the request of the domain owner is
explicitly supported. That stock ("SKU") could be provided to a explicitly supported. That stock ("SKU") could be provided to a
number of potential domain owners, and the eventual domain owner will number of potential domain owners, and the eventual domain owner will
not know a-priori which device will go to which location. not know a-priori which device will go to which location.
The bootstraping process can take minutes to complete depending on The bootstraping process can take minutes to complete depending on
the network infrastructure and device processing speed. The network the network infrastructure and device processing speed. The network
communication itself is not "chatty" but there can be delays for communication itself is not optimized for speed; the discovery
privacy reasons. This protocol is not intended for low latency process allows for the Pledge to avoid broadcasting for privacy
handoffs. reasons. This protocol is not intended for low latency handoffs.
Specifically, there are protocol aspects described here which might Specifically, there are protocol aspects described here which might
result in congestion collapse or energy-exhaustion of intermediate result in congestion collapse or energy-exhaustion of intermediate
battery powered routers in an LLN. Those types of networks SHOULD battery powered routers in an LLN. Those types of networks SHOULD
NOT use this solution. These limitations are predominately related NOT use this solution. These limitations are predominately related
to the large credential and key sizes required for device to the large credential and key sizes required for device
authentication. Defining symmetric key techniques that meet the authentication. Defining symmetric key techniques that meet the
operational requirements is out-of-scope but the underlying protocol operational requirements is out-of-scope but the underlying protocol
operations (TLS handshake and signing structures) have sufficient operations (TLS handshake and signing structures) have sufficient
algorithm agility to support such techniques when defined. algorithm agility to support such techniques when defined.
The imprint protocol described here could, however, be used by non- The imprint protocol described here could, however, be used by non-
energy constrained devices joining a non-constrained network (for energy constrained devices joining a non-constrained network (for
instance, smart light bulbs are usually mains powered, and speak instance, smart light bulbs are usually mains powered, and speak
802.11). It could also be used by non-constrained devices across a 802.11). It could also be used by non-constrained devices across a
non-energy constrained, but challenged network (such as 802.15.4). non-energy constrained, but challenged network (such as 802.15.4).
The use of an IDevID that is consistant with [IDevID] allows for
alignment with 802.1X network access control methods which could need
to complete before bootstrapping can be initiated. This document
presumes that network access control has either already occured, is
not required, or is integrated by the proxy and registrar in such a
way that the device itself does not need to be aware of the details.
Further integration is not in scope.
Some aspects are in scope for constrained devices on challenged Some aspects are in scope for constrained devices on challenged
networks: the certificate contents, and the process by which the four networks: the certificate contents, and the process by which the four
questions above are resolved is in scope. It is simply the actual questions above are resolved is in scope. It is simply the actual
on-the-wire imprint protocol which is likely inappropriate. on-the-wire imprint protocol which is likely inappropriate.
1.3. Trust bootstrap 1.3. Trust bootstrap
The imprint protocol results in a secure relationship between the The imprint protocol results in a secure relationship between a
domain registrar and the new device. If the new device is domain Registrar and the Pledge. If the new device is sufficiently
sufficiently constrained that the ACE protocol should be leveraged constrained that the ACE protocol should be leveraged for operation,
for operation, (see [I-D.ietf-ace-actors]), and the domain registrar (see [I-D.ietf-ace-actors]), and the domain registrar is also the
is also the Client Authorization Server or the Authorization Server, Client Authorization Server or the Authorization Server, then it may
then it may be appropriate to use this secure channel to exchange ACE be appropriate to use this secure channel to exchange ACE tokens.
tokens.
2. Architectural Overview 2. Architectural Overview
The logical elements of the bootstrapping framework are described in The logical elements of the bootstrapping framework are described in
this section. Figure 1 provides a simplified overview of the this section. Figure 1 provides a simplified overview of the
components. Each component is logical and may be combined with other components. Each component is logical and may be combined with other
components as necessary. components as necessary.
. .
.+------------------------+ .+------------------------+
skipping to change at page 8, line 37 skipping to change at page 9, line 37
| | . | Domain Certification | . | | . | Domain Certification | .
| | . | Authority | . | | . | Authority | .
+-------+ . | Management and etc | . +-------+ . | Management and etc | .
. +----------------------------+ . . +----------------------------+ .
. . . .
................................................ ................................................
"Domain" components "Domain" components
Figure 1 Figure 1
Domain: The set of entities that trust a common key infrastructure
trust anchor. This includes the Proxy, Registrar, Domain
Certificate Authority, Management components and any existing
entity that is already a member of the domain.
Domain CA: The domain Certification Authority (CA) provides
certification functionalities to the domain. At a minimum it
provides certification functionalities to the Registrar and stores
the trust anchor that defines the domain. Optionally, it
certifies all elements.
Registrar: A representative of the domain that is configured,
perhaps autonomically, to decide whether a new device is allowed
to join the domain. The administrator of the domain interfaces
with a Registrar to control this process. Typically a Registrar
is "inside" its domain.
New Entity: A new device or virtual machine or software component
that is not yet part of the domain.
Proxy: A domain entity that helps the New Entity join the domain. A
Proxy facilitates communication for devices that find themselves
in an environment where they are not provided connectivity until
after they are validated as members of the domain. The New Entity
is unaware that they are communicating with a proxy rather than
directly with the Registrar.
MASA Service: A Manufacturer Authorized Signing Authority (MASA)
service on the global Internet. The MASA provides a repository
for audit log information concerning privacy protected
bootstrapping events.
Ownership Tracker An Ownership Tracker service on the global
internet. The Ownership Tracker uses business processes to
accurately track ownership of all devices shipped against domains
that have purchased them. Although optional this component allows
vendors to provide additional value in cases where their sales and
distribution channels allow for accurately tracking of such
ownership.
We assume a multi-vendor network. In such an environment there could We assume a multi-vendor network. In such an environment there could
be a MASA or Ownership Tracker for each vendor that supports devices be a MASA or Ownership Tracker for each vendor that supports devices
following this document's specification, or an integrator could following this document's specification, or an integrator could
provide a MASA service for all devices. It is unlikely that an provide a MASA service for all devices. It is unlikely that an
integrator could provide Ownership Tracking services for multiple integrator could provide Ownership Tracking services for multiple
vendors. vendors.
This document describes a secure zero-touch approach to bootstrapping This document describes a secure zero-touch approach to bootstrapping
a key infrastructure; if certain devices in a network do not support a key infrastructure; if certain devices in a network do not support
this approach, they can still be bootstrapped manually. Although this approach, they can still be bootstrapped manually. Although
manual deployment is not scalable and is not a focus of this document manual deployment is not scalable and is not a focus of this document
the necessary mechanisms are called out in this document to ensure the necessary mechanisms are called out in this document to ensure
such edge conditions are covered by the architectural and protocol such edge conditions are covered by the architectural and protocol
models. models.
3. Functional Overview 3. Functional Overview
Entities behave in an autonomic fashion. They discover each other Entities behave in an autonomic fashion. They discover each other
and autonomically bootstrap into a key infrastructure delineating the and autonomically bootstrap into a key infrastructure delineating the
autonomic domain. See [I-D.irtf-nmrg-autonomic-network-definitions] autonomic domain. See [RFC7575] for more information.
for more information.
This section details the state machine and operational flow for each This section details the state machine and operational flow for each
of the main three entities. The New Entity, the Domain (primarily of the main three entities. The pledge, the domain (primarily a
the Registrar) and the MASA service. Registrar) and the MASA service.
A representative flow is shown in Figure 2: A representative flow is shown in Figure 2:
+--------+ +---------+ +------------+ +------------+ +--------+ +---------+ +------------+ +------------+
| New | | Circuit | | Domain | | Vendor | | Pledge | | Circuit | | Domain | | Vendor |
| Entity | | Proxy | | Registrar | | Service | | | | Proxy | | Registrar | | Service |
| | | | | | | (Internet | | | | | | | | (Internet |
+--------+ +---------+ +------------+ +------------+ +--------+ +---------+ +------------+ +------------+
| | | | | | | |
|<-RFC3927 IPv4 adr | | | |<-RFC3927 IPv4 adr | | |
or|<-RFC4862 IPv6 adr | | | or|<-RFC4862 IPv6 adr | | |
| | | | | | | |
|-------------------->| | | |-------------------->| | |
| optional: mDNS query| | | | optional: mDNS query| | |
| RFC6763/RFC6762 | | | | RFC6763/RFC6762 | | |
| | | | | | | |
|<--------------------| | | |<--------------------| | |
| mDNS broadcast | | | | mDNS broadcast | | |
| response or periodic| | | | response or periodic| | |
| | | | | | | |
|<------------------->C<----------------->| | |<------------------->C<----------------->| |
| TLS via the Circuit Proxy | | | TLS via the Circuit Proxy | |
|<--Registrar TLS server authentication---| | |<--Registrar TLS server authentication---| |
[PROVISIONAL accept of server cert] | | [PROVISIONAL accept of server cert] | |
P---IEEE 802.1AR client authentication--->| | P---X.509 client authentication---------->| |
P | | | P | | |
P---Request Audit Token (include nonce)-->| | P---Request Voucher (include nonce)------>| |
P | | | P | | |
P | /---> | | P | /---> | |
P | | [accept device?] | P | | [accept device?] |
P | | [contact Vendor] | P | | [contact Vendor] |
P | | |--New Entity ID---->| P | | |--Pledge ID-------->|
P | | |--Domain ID-------->| P | | |--Domain ID-------->|
P | | |--optional:nonce--->| P | | |--optional:nonce--->|
P | | | [extract DomainID] P | | | [extract DomainID]
P | | | | P | | | |
P | optional: | [update audit log] P | optional: | [update audit log]
P | |can | | P | |can | |
P | |occur | optional: is | P | |occur | |
P | |in | an ownership | P | |in | |
P | |advance | voucher available? P | |advance | |
P | | | | P | | | |
P | | |<-device audit log--| P | | |<-device audit log--|
P | | | | P | | |<- voucher ---------|
P | | | choice: | P | \----> | |
P | | |<-audit token-------|
P | | |<-or: ownership-----|
P | \----> | voucher |
P | | | P | | |
P | [verify audit log or voucher] | P | [verify audit log and voucher] |
P | | | P | | |
P<--Audit token and/or ownership voucher--| | P<------voucher---------------------------| |
[verify response ]| | | [verify voucher ] | | |
[verify provisional cert ]| | | [verify provisional cert ]| | |
| | | | | | | |
|---------------------------------------->| | |---------------------------------------->| |
| Continue with RFC7030 enrollment | | | Continue with RFC7030 enrollment | |
| using now bidirectionally authenticated | | | using now bidirectionally authenticated | |
| TLS session. | | | | TLS session. | | |
| | | | | | | |
| | | | | | | |
| | | | | | | |
Figure 2 Figure 2
3.1. Behavior of a New Entity 3.1. Behavior of a Pledge
A New Entity that has not yet been bootstrapped attempts to find a A pledge that has not yet been bootstrapped attempts to find a local
local domain and join it. A New Entity MUST NOT automatically domain and join it. A pledge MUST NOT automatically initiate
initiate bootstrapping if it has already been configured. bootstrapping if it has already been configured or is in the process
of being configured.
States of a New Entity are as follows: States of a pledge are as follows:
+--------------+ +--------------+
| Start | | Start |
| | | |
+------+-------+ +------+-------+
| |
+------v-------+ +------v-------+
| Discover | | Discover |
+------------> | +------------> |
| +------+-------+ | +------+-------+
skipping to change at page 12, line 43 skipping to change at page 12, line 43
| Enroll +------+-------+ | Enroll +------+-------+
| Failure | | Failure |
| +------v-------+ | +------v-------+
| | Being | | | Being |
^------------+ Managed | ^------------+ Managed |
Factory +--------------+ Factory +--------------+
reset reset
Figure 3 Figure 3
State descriptions for the New Entity are as follows: State descriptions for the pledge are as follows:
1. Discover a communication channel to the "closest" Registrar. 1. Discover a communication channel to a Registrar.
2. Identify itself. This is done by presenting an IEEE 802.1AR 2. Identify itself. This is done by presenting an IDevID X.509
credentials to the discovered Registrar (via the Proxy) in a TLS credential to the discovered Registrar (via the Proxy) in a TLS
handshake. (Although the Registrar is also authenticated these handshake. (The Registrar credentials are only provisionally
credentials are only provisionally accepted at this time). accepted at this time).
3. Requests to Join the discovered Registrar. A unique nonce is 3. Requests to Join the discovered Registrar. A unique nonce is
included ensuring that any responses can be associated with this included ensuring that any responses can be associated with this
particular bootstrapping attempt. particular bootstrapping attempt.
4. Imprint on the Registrar. This requires verification of the 4. Imprint on the Registrar. This requires verification of the
vendor service "Audit Token" or the validation of the vendor vendor service provided "Audit" or "Ownership" Voucher. Either
service "Ownership Voucher". Either of these responses contains of these responses contains sufficient information for the pledge
sufficient information for the New Entity to complete to complete authentication of a Registrar. (The pledge can now
authentication of the Registrar. (The New Entity can now finish finish authentication of the Registrar TLS server certificate)
authentication of the Registrar TLS server certificate)
5. Enroll by accepting the domain specific information from the 5. Enroll by accepting the domain specific information from a
Registrar, and by obtaining a domain certificate from the Registrar, and by obtaining a domain certificate from a Registrar
Registrar using a standard enrollment protocol, e.g. Enrollment using a standard enrollment protocol, e.g. Enrollment over
over Secure Transport (EST) [RFC7030]. Secure Transport (EST) [RFC7030].
6. The New Entity is now a member of, and can be managed by, the 6. The Pledge is now a member of, and can be managed by, the domain
domain and will only repeat the discovery aspects of and will only repeat the discovery aspects of bootstrapping if it
bootstrapping if it is returned to factory default settings. is returned to factory default settings.
The following sections describe each of these steps in more detail. The following sections describe each of these steps in more detail.
3.1.1. Discovery 3.1.1. Discovery
The result of discovery is logically communication with a Proxy The result of discovery is a logical communication with a Registrar,
instead of a Domain Registrar but in such a case the proxy through a Proxy. The Proxy is transparent to the Pledge but is
facilitates communication with the actual Domain Registrar in a always assumed to exist.
manner that is transparent to the New Entity. Therefore or clarity a
Proxy is always assumed.
To discover the Domain Bootstrap Server the New Entity performs the To discover the Registrar the Pledge performs the following actions:
following actions:
a. MUST: Obtains a local address using either IPv4 or IPv6 methods a. MUST: Obtains a local address using either IPv4 or IPv6 methods
as described in [RFC4862] IPv6 Stateless Address as described in [RFC4862] IPv6 Stateless Address
AutoConfiguration or [RFC3927] Dynamic Configuration of IPv4 AutoConfiguration or [RFC3927] Dynamic Configuration of IPv4
Link-Local Addresses. Link-Local Addresses. The Plege MAY obtain an IP address via
DHCP [RFC2131]. The DHCP provided parameters for the Domain Name
System can be used to perform step (d) DNS operations if all
local discovery attempts fail (see below).
b. MUST: Performs DNS-based Service Discovery [RFC6763] over b. MUST: Performs DNS-based Service Discovery [RFC6763] over
Multicast DNS [RFC6762] searching for the service Multicast DNS [RFC6762] searching for the service
"_bootstrapks._tcp.local.". To prevent unaccceptable levels of "_bootstrapks._tcp.local.". To prevent unaccceptable levels of
network traffic the congestion avoidance mechanisms specified in network traffic the congestion avoidance mechanisms specified in
[RFC6762] section 7 MUST be followed. The New Entity SHOULD [RFC6762] section 7 MUST be followed. The Pledge SHOULD listen
listen for an unsolicited broadcast response as described in for an unsolicited broadcast response as described in [RFC6762].
[RFC6762]. This allows devices to avoid announcing their This allows devices to avoid announcing their presence via mDNS
presence via mDNS broadcasts and instead silently join a network broadcasts and instead silently join a network by watching for
by watching for periodic unsolicited broadcast responses. periodic unsolicited broadcast responses.
c. MAY: Performs DNS-based Service Discovery [RFC6763] over normal c. MAY: Performs DNS-based Service Discovery [RFC6763] over normal
DNS operations. The service searched for is DNS operations. The service searched for is
"_bootstrapks._tcp.example.net". In this case the domain "_bootstrapks._tcp.example.com". In this case the domain
"example.net" is discovered as described in [RFC6763] section 11. "example.com" is discovered as described in [RFC6763] section 11.
d. MAY: If no local bootstrapks service is located using the DNS- d. MAY: If no local bootstrapks service is located using the DNS-
based Service Discovery methods the New Entity contacts a well based Service Discovery methods the Pledge contacts a well known
known vendor provided bootstrapping server by performing a DNS vendor provided bootstrapping server by performing a DNS lookup
lookup using a well known URI such as "bootstrapks.vendor- using a well known URI such as "bootstrapks.vendor-example.com".
example.com". The details of the URI are vendor specific. The details of the URI are vendor specific. Vendors that
Vendors that leverage this method SHOULD provision appropriately. leverage this method on the Pledge are responsible for providing
the bootstrapks service.
DNS-based service discovery communicates the local proxy IPv4 or IPv6 DNS-based service discovery communicates the local proxy IPv4 or IPv6
address and port to the New Entity. Once a proxy is discovered the address and port to the Pledge. Once a proxy is discovered the
New Entity communicates with the Registrar through the proxy using Pledge communicates with a Registrar through the proxy using the
the bootstrapping protocol defined in Section 5. The current DNS bootstrapping protocol defined in Section 5. The current DNS
services returned during each query is maintained until bootstrapping services returned during each query is maintained until bootstrapping
is completed. If bootstrapping fails and the New Entity returns to is completed. If bootstrapping fails and the Pledge returns to the
the Discovery state it picks up where it left off and continues Discovery state it picks up where it left off and continues
attempting bootstrapping. For example if the first Multicast DNS attempting bootstrapping. For example if the first Multicast DNS
_bootstrapks._tcp.local response doesn't work then the second and _bootstrapks._tcp.local response doesn't work then the second and
third responses are tried. If these fail the New Entity moves on to third responses are tried. If these fail the Pledge moves on to
normal DNS-based Service Discovery. normal DNS-based Service Discovery.
Each discovery method attempted SHOULD exponentially back-off Each discovery method attempted SHOULD exponentially back-off
attempts (to a maximum of one hour) to avoid overloading that attempts (to a maximum of one hour) to avoid overloading the network
discovery methods network infrastructure. The back-off timer for infrastructure with discovery. The back-off timer for each method
each method MUST be independent of other methods. Methods SHOULD be MUST be independent of other methods. Methods SHOULD be run in
run in parallel to avoid head of queue problems. Once a connection parallel to avoid head of queue problems. Once a connection to a
to a Registrar is established (e.g. establishment of a TLS session Registrar is established (e.g. establishment of a TLS session key)
key) there are expectations of more timely responses, see there are expectations of more timely responses, see Section 5.1.
Section 5.1.
Once all discovered services are attempted the device SHOULD return Once all discovered services are attempted the device SHOULD return
to Multicast DNS. It should periodically retry the vendor specific to Multicast DNS. It should periodically retry the vendor specific
mechanisms. The New Entity may prioritize selection order as mechanisms. The Pledge may prioritize selection order as appropriate
appropriate for the anticipated environment. for the anticipated environment.
3.1.2. Identity 3.1.2. Identity
The New Entity identifies itself during the communication protocol The Pledge identifies itself during the communication protocol
handshake. If the client identity is rejected the New Entity repeats handshake. If the client identity is rejected the Pledge repeats the
the Discovery process using the next proxy or discovery method Discovery process using the next proxy or discovery method available.
available.
The bootstrapping protocol server is not initially authenticated. The bootstrapping protocol server is not initially authenticated.
Thus the connection is provisional and all data received is untrusted Thus the connection is provisional and all data received is untrusted
until sufficiently validated even though it is over a TLS connection. until sufficiently validated even though it is over a TLS connection.
This is aligned with the existing provisional mode of EST [RFC7030] This is aligned with the existing provisional mode of EST [RFC7030]
during s4.1.1 "Bootstrap Distribution of CA Certificates". See during s4.1.1 "Bootstrap Distribution of CA Certificates". See
Section 5.3 for more information about when the TLS connection Section 5.3 for more information about when the TLS connection
authenticated is completed. authenticated is completed.
All security associations established are between the new device and All security associations established are between the new device and
the Bootstrapping server regardless of proxy operations. the Bootstrapping server regardless of proxy operations.
3.1.3. Request Join 3.1.3. Request Join
skipping to change at page 15, line 15 skipping to change at page 15, line 13
This is aligned with the existing provisional mode of EST [RFC7030] This is aligned with the existing provisional mode of EST [RFC7030]
during s4.1.1 "Bootstrap Distribution of CA Certificates". See during s4.1.1 "Bootstrap Distribution of CA Certificates". See
Section 5.3 for more information about when the TLS connection Section 5.3 for more information about when the TLS connection
authenticated is completed. authenticated is completed.
All security associations established are between the new device and All security associations established are between the new device and
the Bootstrapping server regardless of proxy operations. the Bootstrapping server regardless of proxy operations.
3.1.3. Request Join 3.1.3. Request Join
The New Entity POSTs a request to join the domain to the The Pledge POSTs a request to join the domain to the Bootstrapping
Bootstrapping server. This request contains a New Entity generated server. This request contains a Pledge generated nonce and informs
nonce and informs the Bootstrapping server which imprint methods the the Bootstrapping server which imprint methods the Pledge will
New Entity will accept. accept.
As indicated in EST [RFC7030] the bootstrapping server MAY redirect As indicated in EST [RFC7030] the bootstrapping server MAY redirect
the client to an alternate server. This is most useful in the case the client to an alternate server. This is most useful in the case
where the New Entity has resorted to a well known vendor URI and is where the Pledge has resorted to a well known vendor URI and is
communicating with the vendor's Registrar directly. In this case the communicating with the vendor's Registrar directly. In this case the
New Entity has authenticated the Registrar using the local Implicit Pledge has authenticated the Registrar using the local Implicit Trust
Trust Anchor database and can therefore treat the redirect URI as a Anchor database and can therefore treat the redirect URI as a trusted
trusted URI which can also be validated using the Implicit Trust URI which can also be validated using the Implicit Trust Anchor
Anchor database. Since client authentication occurs during the TLS database. Since client authentication occurs during the TLS
handshake the bootstrapping server has sufficient information to handshake the bootstrapping server has sufficient information to
apply appropriate policy concerning which server to redirect to. apply appropriate policy concerning which server to redirect to.
The nonce ensures the New Entity can verify that responses are The nonce ensures the Pledge can verify that responses are specific
specific to this bootstrapping attempt. This minimizes the use of to this bootstrapping attempt. This minimizes the use of global time
global time and provides a substantial benefit for devices without a and provides a substantial benefit for devices without a valid clock.
valid clock.
3.1.4. Imprint 3.1.4. Imprint
The domain trust anchor is received by the New Entity during the The domain trust anchor is received by the Pledge during the
bootstrapping protocol methods in the form of either an Audit Token bootstrapping protocol methods in the form of a voucher. The goal of
containing the domain CA cert or an explicit ownership voucher. The the imprint state is to securely obtain a copy of this trust anchor
goal of the imprint state is to securely obtain a copy of this trust without involving human interaction.
anchor without involving human interaction.
The enrollment protocol EST [RFC7030] details a set of non-autonomic The enrollment protocol EST [RFC7030] details a set of non-autonomic
bootstrapping methods such as: bootstrapping methods such as:
o using the Implicit Trust Anchor database (not an autonomic o using the Implicit Trust Anchor database (not an autonomic
solution because the URL must be securely distributed), solution because the URL must be securely distributed),
o engaging a human user to authorize the CA certificate using out- o engaging a human user to authorize the CA certificate using out-
of-band data (not an autonomic solution because the human user is of-band data (not an autonomic solution because the human user is
involved), involved),
o using a configured Explicit TA database (not an autonomic solution o using a configured Explicit TA database (not an autonomic solution
because the distribution of an explicit TA database is not because the distribution of an explicit TA database is not
autonomic), autonomic),
o and using a Certificate-Less TLS mutual authentication method (not o and using a Certificate-Less TLS mutual authentication method (not
an autonomic solution because the distribution of symmetric key an autonomic solution because the distribution of symmetric key
material is not autonomic). material is not autonomic).
This document describes additional autonomic methods: This document describes autonomic methods that MUST be supported by
the Pledge:
MASA audit token Audit tokens are obtained by the Registrar from the Audit Voucher Audit Vouchers are obtained by a Registrar from the
MASA service and presented to the New Entity for validation. MASA service and presented to the Pledge for validation. These
These indicate to the New Entity that joining the domain has been indicate to the Pledge that joining the domain has been logged by
logged by a logging service. a logging service.
Ownership Voucher Ownership Vouchers are obtained by the Registrar Ownership Voucher Ownership Vouchers are obtained by a Registrar
from the MASA service and explicitly indicate the fully qualified from the MASA service and explicitly indicate the owner of the
domain name of the domain the new entity currently belongs to. Pledge. The Ownership Voucher is defined in
The Ownership Voucher is defined in [I-D.ietf-netconf-zerotouch]. [I-D.ietf-netconf-zerotouch].
Since client authentication occurs during the TLS handshake the Since client authentication occurs during the TLS handshake the
bootstrapping server has sufficient information to apply appropriate bootstrapping server has sufficient information to apply appropriate
policy concerning which method to use. policy concerning which method to use.
The audit token contains the domain's public key material as provided The Audit Voucher contains the domain's public key material as
to the MASA service by the Registrar. This provides sufficient provided to the MASA service by a Registrar. This provides
information to the client to complete automated bootstrapping with sufficient information to the client to complete automated
the local key infrastructure. bootstrapping with the local key infrastructure. The Ownership
Voucher contains the Owner Certificate which the Pledge uses to
authenticate the TLS connection.
If the autonomic methods fail the New Entity returns to discovery If the autonomic methods fail the Pledge returns to discovery state
state and attempts bootstrapping with the next available discovered and attempts bootstrapping with the next available discovered
Registrar. Registrar.
3.1.5. Lack of realtime clock 3.1.5. Lack of realtime clock
Many devices when bootstrapping do not have knowledge of the current Many devices when bootstrapping do not have knowledge of the current
time. Mechanisms like Network Time Protocols can not be secured time. Mechanisms like Network Time Protocols can not be secured
until bootstrapping is complete. Therefore bootstrapping is defined until bootstrapping is complete. Therefore bootstrapping is defined
in a method that does not require knowledge of the current time. in a method that does not require knowledge of the current time.
Unfortunately there are moments during bootstrapping when Unfortunately there are moments during bootstrapping when
certificates are verified, such as during the TLS handshake, where certificates are verified, such as during the TLS handshake, where
validity periods are confirmed. This paradoxical "catch-22" is validity periods are confirmed. This paradoxical "catch-22" is
resolved by the New Entity maintaining a concept of the current resolved by the Pledge maintaining a concept of the current "window"
"window" of presumed time validity that is continually refined of presumed time validity that is continually refined throughout the
throughout the bootstrapping process as follows: bootstrapping process as follows:
o Initially the New Entity does not know the current time. The o Initially the Pledge does not know the current time.
nonce included in join attempts provides an alternate mechanism
for the New Entity to ensure responses are associated with a
particular bootstrapping attempt. Nonceless audit tokens from the
MASA server are always valid and thus time is not needed.
o In accordance with IEEE 802.1AR and RFC5280 all manufacturing o During Pledge authentiation by the Registrar a realtime clock can
installed certificates and trust anchors are assumed to have be used by the Registrar. This bullet expands on a closely
infinite lifetimes. All such certificates "SHOULD be assigned the related issue regarding Pledge lifetimes. RFC5280 indicates that
GeneralizedTime value of 99991231235959Z" [RFC5280]. The New long lived Pledge certifiates "SHOULD be assigned the
Entity, Registrar and MASA server MUST ignore any other validity GeneralizedTime value of 99991231235959Z" [RFC5280] so the
period information in these credentials and treat the effective Registrar MUST support such lifetimes and SHOULD support ignoring
lifetime as 99991231235959Z. This ensures that client Pledge lifetimes if they did not follow the RFC5280
authentication (see Section 3.3.1) and the audit token signature recommendations.
(see Section 5.3) can always be verified during RFC5280 path
validation.
o Once the audit token is accepted the validity period of the o Once the Audit Voucher is accepted the validity period of the
domainCAcert in the token (see Section 5.3) now describes a valid domainCAcert in the voucher (see Section 5.3) now describes a
time window. Any subsequent certificate validity periods checked valid time window. Any subsequent certificate validity periods
during RFC5280 path validation MUST occur within this window. checked during RFC5280 path validation MUST occur within this
window.
o When accepting an enrollment certificate the validity period o When accepting an enrollment certificate the validity period
within the new end entity certificate is assumed to be valid by within the new certificate is assumed to be valid by the Pledge.
the New Entity. The New Entity is now willing to use this The Pledge is now willing to use this credential for client
credential for client authentication. authentication.
Once in this state the New Entity has a valid trust anchor with the Once in this state the Pledge has a valid trust anchor with the local
local domain and has a locally issued credential. These MAY be used domain and has a locally issued credential. These MAY be used to
to secure distribution of more accurate time information although secure distribution of more accurate time information although
specification of such a protocol is out-of-scope of this document. specification of such a protocol is out-of-scope of this document.
The nonce included in join attempts provides an alternate mechanism
for the Pledge to ensure Audit Voucher responses are associated with
a particular bootstrapping attempt. Nonceless Audit Vouchers from
the MASA server are always valid and thus time is not needed.
Ownership Vouchers include time information and MUST be validated
using a realtime clock.
3.1.6. Enrollment 3.1.6. Enrollment
As the final step of bootstrapping a Registrar helps to issue a As the final step of bootstrapping a Registrar helps to issue a
domain specific credential to the New Entity. For simplicity in this domain specific credential to the Pledge. For simplicity in this
document, a Registrar primarily facilitates issuing a credential by document, a Registrar primarily facilitates issuing a credential by
acting as an RFC5280 Registration Authority for the Domain acting as an RFC5280 Registration Authority for the Domain
Certification Authority. Certification Authority.
Enrollment proceeds as described in Enrollment over Secure Transport Enrollment proceeds as described in [RFC7030]. Authentication of the
(EST) [RFC7030]. The New Entity contacts the Registrar using EST as EST server is done using the Voucher rather than the methods defined
indicated: in EST.
o The New Entity is authenticated using the IEEE 802.1AR
credentials.
o The EST section 4.1.3 CA Certificates Response is verified using
either the Audit Token which provided the domain identity -or-
o The EST server is authenticated by using the Ownership Voucher
indicated fully qualified domain name to build the EST URI such
that EST section 4.1.1 bootstrapping using the New Entity implicit
Trust Anchor database can be used.
Once the Audit Token is received, as specified in this document, the Once the Audit or Ownership Voucher is received, as specified in this
client has sufficient information to leverage the existing document, the client has sufficient information to leverage the
communication channel with the Registrar to continue an EST RFC7030 existing communication channel with a Registrar to continue an EST
enrollment. Enrollment picks up at RFC7030 section 4.1.1. RFC7030 enrollment. Enrollment picks up at RFC7030 section 4.1.1.
bootstrapping where the audit token provides the "out-of-band" CA bootstrapping where the Audit Voucher provides the "out-of-band" CA
certificate fingerprint (in this case the full CA certificate) such certificate fingerprint (in this case the full CA certificate) such
that the client can now complete the TLS server authentication. At that the client can now complete the TLS server authentication. At
this point the client continues with EST enrollment operations this point the client continues with EST enrollment operations
including "CA Certificates Request", "CSR Attributes" and "Client including "CA Certificates Request", "CSR Attributes" and "Client
Certificate Request" or "Server-Side Key Generation". Certificate Request" or "Server-Side Key Generation".
3.1.7. Being Managed 3.1.7. Being Managed
Functionality to provide generic "configuration" information is Functionality to provide generic "configuration" information is
supported. The parsing of this data and any subsequent use of the supported. The parsing of this data and any subsequent use of the
data, for example communications with a Network Management System is data, for example communications with a Network Management System is
out of scope but is expected to occur after bootstrapping enrollment out of scope but is expected to occur after bootstrapping enrollment
is complete. This ensures that all communications with management is complete. This ensures that all communications with management
systems which can divulge local security information (e.g. network systems which can divulge local security information (e.g. network
topology or raw key material) is secured using the local credentials topology or raw key material) is secured using the local credentials
issued during enrollment. issued during enrollment.
The New Entity uses bootstrapping to join only one domain. The Pledge uses bootstrapping to join only one domain. Management by
Management by multiple domains is out-of-scope of bootstrapping. multiple domains is out-of-scope of bootstrapping. After the device
After the device has successfully joined a domain and is being has successfully joined a domain and is being managed it is plausible
managed it is plausible that the domain can insert credentials for that the domain can insert credentials for other domains depending on
other domains depending on the device capabilities. the device capabilities.
See Section 3.5. See Section 3.5.
3.2. Behavior of a Proxy 3.2. Behavior of a Proxy
The role of the Proxy is to facilitate communications. The Proxy The role of the Proxy is to facilitate communications. The Proxy
forwards packets between the New Entity and the Registrar that has forwards packets between the Pledge and a Registrar that has been
been configured on the Proxy. The Proxy does not terminate the TLS configured on the Proxy. The Proxy does not terminate the TLS
handshake. handshake. A Proxy is always assumed even if directly integrated
into a Registrar.
As a result of the Proxy Discovery process in section Section 3.1.1,
the port number exposed by the proxy does not need to be well known,
or require an IANA allocation.
If the Proxy joins an Autonomic Control Plane
([I-D.ietf-anima-autonomic-control-plane]) it SHOULD use Autonomic
Control Plane secured GRASP ([I-D.ietf-anima-grasp]) to discovery the
Registrar address and port. For the IPIP encapsulation methods, the
port announced by the Proxy MUST be the same as on the registrar in
order for the proxy to remain stateless.
In order to permit the proxy functionality to be implemented on the In order to permit the proxy functionality to be implemented on the
maximum variety of devices the chosen mechanism SHOULD use the maximum variety of devices the chosen mechanism SHOULD use the
minimum amount of state on the proxy device. While many devices in minimum amount of state on the proxy device. While many devices in
the ANIMA target space will be rather large routers, the proxy the ANIMA target space will be rather large routers, the proxy
function is likely to be implemented in the control plane CPU such a function is likely to be implemented in the control plane CPU such a
device, with available capabilities for the proxy function similar to device, with available capabilities for the proxy function similar to
many class 2 IoT devices. many class 2 IoT devices.
The document [I-D.richardson-anima-state-for-joinrouter] provides a The document [I-D.richardson-anima-state-for-joinrouter] provides a
skipping to change at page 19, line 25 skipping to change at page 19, line 33
for CoAP traffic to the configured UDP port on the registrar. The for CoAP traffic to the configured UDP port on the registrar. The
proxy does not terminate the CoAP DTLS connection. [[EDNOTE: The proxy does not terminate the CoAP DTLS connection. [[EDNOTE: The
choice of CoAP as the mandatory to implement protocol rather than choice of CoAP as the mandatory to implement protocol rather than
HTTP maximizes code reuse on the smallest of devices. Unfortunately HTTP maximizes code reuse on the smallest of devices. Unfortunately
this means this document will have to include the EST over CoAP this means this document will have to include the EST over CoAP
details as additional sections. The alternative is to make 'HTTPS details as additional sections. The alternative is to make 'HTTPS
proxy' method the mandatory to implement and provide a less friendly proxy' method the mandatory to implement and provide a less friendly
environment for the smallest of devices. This is a decision we'll environment for the smallest of devices. This is a decision we'll
have to see addressed by the broader team.]] have to see addressed by the broader team.]]
As a result of the Proxy Discovery process in section Section 3.1.1,
the port number exposed by the proxy does not need to be well known,
or require an IANA allocation.
The address and port of the Registrar to which the packets will be
forwarded will be discovered by the GRASP protocol inside the ACP.
For the IPIP encapsulation methods, the port announced by the Proxy
MUST be the same as on the registrar in order for the proxy to remain
stateless.
The IPIP encapsulation allows the proxy to forward traffic which is The IPIP encapsulation allows the proxy to forward traffic which is
otherwise not to be forwarded, as the traffic between New Node and otherwise not to be forwarded, as the traffic between New Node and
Proxy use IPv6 Link Local addresses. Proxy use IPv6 Link Local addresses.
If the Proxy device has more than one interface on which it offers If the Proxy device has more than one interface on which it offers
the proxy function, then it must select a unique (ACP) IP address per the proxy function, then it must select a unique (ACP) IP address per
interface in order so that the proxy can stateless return the reply interface in order so that the proxy can stateless return the (link-
packets to the correct link. local) reply packets to the correct link.
3.2.2. HTTPS proxy connection to Registrar 3.2.2. HTTPS proxy connection to Registrar
The proxy SHOULD also provide one of: an IPIP encapsulation of HTTP The proxy SHOULD also provide one of: an IPIP encapsulation of HTTP
traffic on TCP port TBD to the registrar, or a TCP circuit proxy that traffic on TCP port TBD to the registrar, or a TCP circuit proxy that
connects the New Node to the Registrar. connects the Pledge to a Registrar.
When the Proxy provides a circuit proxy to the Registrar the When the Proxy provides a circuit proxy to a Registrar the Registrar
Registrar MUST accept HTTPS connections. MUST accept HTTPS connections.
When the Proxy provides a stateless IPIP encapsulation to the When the Proxy provides a stateless IPIP encapsulation to a
Registrar, then the Registrar will have to perform IPIP Registrar, then the Registrar will have to perform IPIP
decapsulation, remembering the originating outer IPIP source address decapsulation, remembering the originating outer IPIP source address
in order to qualify the inner link-local address. This is a kind of in order to qualify the inner link-local address. This is a kind of
encapsulation and processing which is similar in many ways to how encapsulation and processing which is similar in many ways to how
mobile IP works. mobile IP works.
Being able to connect a TCP (HTTP) or UDP (CoAP) socket to a link- Being able to connect a TCP (HTTP) or UDP (CoAP) socket to a link-
local address with an encapsulated IPIP header requires API local address with an encapsulated IPIP header requires API
extensions beyond [RFC3542] for UDP use, and requires a form of extensions beyond [RFC3542] for UDP use, and requires a form of
connection latching (see section 4.1 of [RFC5386] and all of connection latching (see section 4.1 of [RFC5386] and all of
[RFC5660], except that a simple IPIP tunnel is used rather than an [RFC5660], except that a simple IPIP tunnel is used rather than an
IPsec tunnel). IPsec tunnel).
3.3. Behavior of the Registrar (Bootstrap Server) 3.3. Behavior of the Registrar
Once a Registrar is established it listens for new entities and A Registrar listens for Pledges and determines if they can join the
determines if they can join the domain. The registrar delivers any domain. A Registrar obtains a Voucher from the MASA service and
necessary authorization information to the new device and facilitates delivers them to the Pledge as well as facilitating enrollment with
enrollment with the domain PKI. the domain PKI.
A Registrar is typically configured manually. If the Registrar joins
an Autonomic Control Plane ([I-D.ietf-anima-autonomic-control-plane])
it MUST use Autonomic Control Plane secured GRASP
([I-D.ietf-anima-grasp]) to broadcast the Registrar's address and
port to potential Proxies.
Registrar behavior is as follows: Registrar behavior is as follows:
Contacted by New Entity Contacted by Pledge
+ +
| |
+-------v----------+ +-------v----------+
| Entity | fail? | Entity | fail?
| Authentication +---------+ | Authentication +---------+
+-------+----------+ | +-------+----------+ |
| | | |
+-------v----------+ | +-------v----------+ |
| Entity | fail? | | Entity | fail? |
| Authorization +---------> | Authorization +--------->
skipping to change at page 21, line 31 skipping to change at page 21, line 31
+-------+----------+ | +-------+----------+ |
| | | |
+-------v----------+ | +-------v----------+ |
| Log Verification | fail? | | Log Verification | fail? |
| +---------> | +--------->
+-------+----------+ | +-------+----------+ |
| | | |
+-------v----------+ +----v-------+ +-------v----------+ +----v-------+
| Forward | | | | Forward | | |
| Audit | | Reject | | Audit | | Reject |
| token + config | | Device | | voucher + config | | Device |
| to the Entity | | | | to the Entity | | |
+------------------+ +------------+ +------------------+ +------------+
Figure 4 Figure 4
3.3.1. Entity Authentication 3.3.1. Pledge Authentication
The applicable authentication methods detailed in EST [RFC7030] are: The applicable authentication methods detailed in EST [RFC7030] are:
o the use of an IEEE 802.1AR IDevID credential during the TLS client o the use of an IDevID X.509 credential during the TLS client
authentication, authentication,
o or the use of a secret that is transmitted out of band between the o or the use of a secret that is transmitted out of band between the
New Entity and the Registrar (this use case is not autonomic). Pledge and a Registrar (this use case is not autonomic).
3.3.2. Entity Authorization In order to validate the IDevID X.509 credential a Registrar
maintains a database of vendor trust anchors (e.g. vendor root
certificates or keyIdentifiers for vendor root public keys). For
user interface purposes this database can be mapped to colloquial
vendor names. Registrars can be shipped with the trust anchors of a
significant number of third-party vendors within the target market.
3.3.2. Pledge Authorization
In a fully automated network all devices must be securely identified In a fully automated network all devices must be securely identified
and authorized to join the domain. and authorized to join the domain.
A Registrar accepts or declines a request to join the domain, based A Registrar accepts or declines a request to join the domain, based
on the authenticated identity presented. Automated acceptance on the authenticated identity presented. Automated acceptance
criteria include: criteria include:
o allow any device of a specific type (as determined by the IEEE o allow any device of a specific type (as determined by the X.509
802.1AR device identity), IDevID),
o allow any device from a specific vendor (as determined by the IEEE o allow any device from a specific vendor (as determined by the
802.1AR identity), X.509 IDevID),
o allow a specific device from a vendor (as determined by the IEEE o allow a specific device from a vendor (as determined by the X.509
802.1AR identity) IDevID) against a domain white list. (The mechanism for checking
a shared white list potentiatlly used by multiple Registrars is
out of scope).
Since all New Entities accept Audit Tokens the Registrar MUST use the To look the Pledge up in a domain white list a consistent method for
extracting device identity from the X.509 certificate is required.
RFC6125 describes Domain-Based Application Service identity but here
we require Vendor Device-Based identity. The subject field's DN
encoding MUST include the "serialNumber" attribute with the device's
unique serial number. In the language of RFC6125 this provides for a
SERIALNUM-ID category of identifier that can be included in a
certificate and therefore that can also be used for matching
purposes. The SERIALNUM-ID whitelist is collated according to vendor
trust anchor since serial numbers are not globally unique.
Since all Pledges accept Audit Vouchers a Registrar MUST use the
vendor provided MASA service to verify that the device's history log vendor provided MASA service to verify that the device's history log
does not include unexpected Registrars. If a device had previously does not include unexpected Registrars. If a device had previously
registered with another domain, the Registrar of that domain would registered with another domain, a Registrar of that domain would show
show in the log. in the log.
In order to validate the IEEE 802.1AR device identity the Registrar
maintains a database of vendor trust anchors (e.g. vendor root
certificates or keyIdentifiers for vendor root public keys). For
user interface purposes this database can be mapped to colloquial
vendor names. Registrars can be shipped with the trust anchors of a
significant number of third-party vendors within the target market.
If a device is accepted into the domain, it is expected request a If a Pledge is accepted into the domain, it is expected to request a
domain certificate through a certificate enrollment process. The domain certificate through a certificate enrollment process. The
result is a common trust anchor and device certificates for all result is a common trust anchor and device certificates for all
autonomic devices in a domain (these certificates can subsequently be autonomic devices in a domain (these certificates can be used for
used to determine the boundaries of the homenet, to authenticate other methods, for example boundary detection, auto-securing
other domain nodes, and to autonomically enable services on the protocols, etc.). The authorization performed during this phase is
homenet). The authorization performed during this phase MAY be used for EST enrollment requests.
cached for the TLS session and applied to subsequent EST enrollment
requests so long as the session lasts.
3.3.3. Claiming the New Entity 3.3.3. Claiming the New Entity
Claiming an entity establishes an audit log at the MASA server and Claiming an entity establishes an audit log at the MASA server and
provides the Registrar with proof, in the form of a MASA provides a Registrar with proof, in the form of a MASA Audit Voucher,
authorization token, that the log entry has been inserted. As that the log entry has been inserted. As indicated in Section 3.1.4
indicated in Section 3.1.4 a New Entity will only proceed with a Pledge will only proceed with bootstrapping if a validated MASA
bootstrapping if a validated MASA authorization token has been Audit Voucher has been received. The Pledge therefore enforces that
received. The New Entity therefore enforces that bootstrapping only bootstrapping only occurs if the claim has been logged. There is no
occurs if the claim has been logged. There is no requirement for the requirement for the vendor to definitively know that the device is
vendor to definitively know that the device is owned by the owned by the Registrar.
Registrar.
Registrar's obtain the Vendor URI via static configuration or by Registrar's obtain the Vendor URI via static configuration or by
extracting it from the IEEE 802.1AR credential. The imprint method extracting it from the X.509 IDevID credential. The imprint method
supported by the New Entity is known from the IEEE 802.1AR supported by the Pledge is known from the X.509 IDevID credential.
credential. [[EDNOTE: An appropriate extension for indicating the [[EDNOTE: An appropriate extension for indicating the Vendor URI and
Vendor URI and imprint method could be defined using the methods imprint method could be defined using the methods described in
described in [I-D.lear-mud-framework]]]. [I-D.lear-mud-framework]]].
During initial bootstrapping the New Entity provides a nonce specific During initial bootstrapping the Pledge provides a nonce specific to
to the particular bootstrapping attempt. The Registrar SHOULD the particular bootstrapping attempt. The Registrar SHOULD include
include this nonce when claiming the New Entity from the MASA this nonce when claiming the Pledge from the MASA service. Claims
service. Claims from an unauthenticated Registrar are only serviced from an unauthenticated Registrar are only serviced by the MASA
by the MASA resource if a nonce is provided. resource if a nonce is provided.
The Registrar can claim a New Entity that is not online by forming The Registrar can claim a Pledge that is not online by forming the
the request using the entities unique identifier and not including a request using the entities unique identifier and not including a
nonce in the claim request. Audit Tokens obtained in this way do not nonce in the claim request. Audit Voucher obtained in this way do
have a lifetime and they provide a permanent method for the domain to not have a lifetime and they provide a permanent method for the
claim the device. Evidence of such a claim is provided in the audit domain to claim the device. Evidence of such a claim is provided in
log entries available to any future Registrar. Such claims reduce the audit log entries available to any future Registrar. Such claims
the ability for future domains to secure bootstrapping and therefore reduce the ability for future domains to secure bootstrapping and
the Registrar MUST be authenticated by the MASA service. therefore the Registrar MUST be authenticated by the MASA service
although no requirement is implied that the MASA associates this
authentication with ownership.
An ownership voucher requires the vendor to definitively know that a An Ownership Voucher requires the vendor to definitively know that a
device is owned by a specific domain. The method used to "claim" device is owned by a specific domain. The method used to "claim"
this are out-of-scope. The Registrar simply requests an ownership this are out-of-scope. A MASA ignores or reports failures when an
validation token and the New Entity trusts the response. attempt is made to claim a device that has a an Ownership Voucher.
3.3.4. Log Verification 3.3.4. Log Verification
The Registrar requests the log information for the new entity from A Registrar requests the log information for the Pledge from the MASA
the MASA service. The log is verified to confirm that the following service. The log is verified to confirm that the following is true
is true to the satisfaction of the Registrar's configured policy: to the satisfaction of a Registrar's configured policy:
o Any nonceless entries in the log are associated with domainIDs o Any nonceless entries in the log are associated with domainIDs
recognized by the registrar. recognized by the registrar.
o Any nonce'd entries are older than when the domain is known to o Any nonce'd entries are older than when the domain is known to
have physical possession of the new entity or that the domainIDs have physical possession of the Pledge or that the domainIDs are
are recognized by the registrar. recognized by the registrar.
If any of these criteria are unacceptable to the registrar the entity If any of these criteria are unacceptable to a Registrar the entity
is rejected. The Registrar MAY be configured to ignore the history is rejected. A Registrar MAY be configured to ignore the history of
of the device but it is RECOMMENDED that this only be configured if the device but it is RECOMMENDED that this only be configured if
hardware assisted NEA [RFC5209] is supported. hardware assisted NEA [RFC5209] is supported.
This document specifies a simple log format as provided by the MASA This document specifies a simple log format as provided by the MASA
service to the registar. This format could be improved by service to the registar. This format could be improved by
distributed consensus technologies that integrate the audit token distributed consensus technologies that integrate the Audit Voucher
with a current technologies such as block-chain or hash trees or the with a current technologies such as block-chain or hash trees or the
like. Doing so is out of the scope of this document but are like. Doing so is out of the scope of this document but are
anticipated improvements for future work. anticipated improvements for future work.
3.4. Behavior of the MASA Service 3.4. Behavior of the MASA Service
The MASA service is provided by the Factory provider on the global The MASA service is provided by the Factory provider on the global
Internet. The URI of this service is well known. The URI SHOULD Internet. The URI of this service is well known. The URI SHOULD
also be provided as an IEEE 802.1AR IDevID X.509 extension (a "MASA also be provided as an X.509 IDevID extension (a "MASA Audit Voucher
Audit Token Distribution Point" extension). Distribution Point" extension).
The MASA service provides the following functionalities to The MASA service provides the following functionalities to
Registrars: Registrars:
3.4.1. Issue Authorization Token and Log the event 3.4.1. Issue Audit Voucher and Log the event
A Registrar POSTs a claim message optionally containing the bootstrap A Registrar POSTs a claim message optionally containing the bootstrap
nonce to the MASA server. nonce to the MASA server.
If a nonce is provided the MASA service responds to all requests. If a nonce is provided the MASA service responds to all requests.
The MASA service verifies the Registrar is representative of the The MASA service verifies the Registrar is representative of the
domain and generates a privacy protected log entry before responding domain and generates a privacy protected log entry before responding
with the Audit Token. with the Audit Voucher. For the simple log format defined in this
document using the DomainID is considered sufficient privacy. Future
work to improve the logging mechanism could include additional
privacy protections.
If a nonce is not provided then the MASA service MUST authenticate If a nonce is not provided then the MASA service MUST authenticate
the Registrar as a valid customer. This prevents denial of service the Registrar as a valid customer. This prevents denial of service
attacks. attacks.
3.4.2. Retrieve Audit Entries from Log 3.4.2. Retrieve Audit Entries from Log
When determining if a New Entity should be accepted into a domain the When determining if a Pledge should be accepted into a domain the
Registrar retrieves a copy of the audit log from the MASA service. Registrar retrieves a copy of the audit log from the MASA service.
This contains a list of privacy protected domain identities that have This contains a list of privacy protected domain identities that have
previously claimed the device. Included in the list is an indication previously claimed the device. Included in the list is an indication
of the time the entry was made and if the nonce was included. of the time the entry was made and if the nonce was included.
3.5. Leveraging the new key infrastructure / next steps 3.5. Leveraging the new key infrastructure / next steps
As the devices have a common trust anchor, device identity can be As the devices have a common trust anchor, device identity can be
securely established, making it possible to automatically deploy securely established, making it possible to automatically deploy
services across the domain in a secure manner. services across the domain in a secure manner.
skipping to change at page 25, line 19 skipping to change at page 25, line 33
When a device has joined the domain, it can validate the domain When a device has joined the domain, it can validate the domain
membership of other devices. This makes it possible to create trust membership of other devices. This makes it possible to create trust
boundaries where domain members have higher level of trusted than boundaries where domain members have higher level of trusted than
external devices. Using the autonomic User Interface, specific external devices. Using the autonomic User Interface, specific
devices can be grouped into to sub domains and specific trust levels devices can be grouped into to sub domains and specific trust levels
can be implemented between those. can be implemented between those.
3.6. Interactions with Network Access Control 3.6. Interactions with Network Access Control
The assumption is that Network Access Control (NAC) completes using The assumption is that Network Access Control (NAC) completes using
the New Entity 802.1AR credentials and results in the device having the Pledge 's X.509 IDevID credentials and results in the device
sufficient connectivity to discovery and communicate with the proxy. having sufficient connectivity to discovery and communicate with the
Any additional connectivity or quarantine behavior by the NAC proxy. Any additional connectivity or quarantine behavior by the NAC
infrastructure is out-of-scope. After the devices has completed infrastructure is out-of-scope. After the devices has completed
bootstrapping the mechanism to trigger NAC to re-authenticate the bootstrapping the mechanism to trigger NAC to re-authenticate the
device and provide updated network privileges is also out-of-scope. device and provide updated network privileges is also out-of-scope.
This achieves the goal of a bootstrap architecture that can integrate This achieves the goal of a bootstrap architecture that can integrate
with NAC but does not require NAC within the network where it wasn't with NAC but does not require NAC within the network where it wasn't
previously required. Future optimizations can be achieved by previously required. Future optimizations can be achieved by
integrating the bootstrapping protocol directly into an initial EAP integrating the bootstrapping protocol directly into an initial EAP
exchange. exchange.
skipping to change at page 26, line 10 skipping to change at page 26, line 27
devices in the domain are configured take on a Registrar function. devices in the domain are configured take on a Registrar function.
A device can be configured to act as a Registrar or a device can A device can be configured to act as a Registrar or a device can
auto-select itself to take on this function, using a detection auto-select itself to take on this function, using a detection
mechanism to resolve potential conflicts and setup communication with mechanism to resolve potential conflicts and setup communication with
the Domain Certification Authority. Automated Registrar selection is the Domain Certification Authority. Automated Registrar selection is
outside scope for this document. outside scope for this document.
4.3. Accepting New Entities 4.3. Accepting New Entities
For each New Entity the Registrar is informed of the unique For each Pledge the Registrar is informed of the unique identifier
identifier (e.g. serial number) along with the manufacturer's (e.g. serial number) along with the manufacturer's identifying
identifying information (e.g. manufacturer root certificate). This information (e.g. manufacturer root certificate). This can happen in
can happen in different ways: different ways:
1. Default acceptance: In the simplest case, the new device asserts 1. Default acceptance: In the simplest case, the new device asserts
its unique identity to the registrar. The registrar accepts all its unique identity to a Registrar. The registrar accepts all
devices without authorization checks. This mode does not provide devices without authorization checks. This mode does not provide
security against intruders and is not recommended. security against intruders and is not recommended.
2. Per device acceptance: The new device asserts its unique identity 2. Per device acceptance: The new device asserts its unique identity
to the registrar. A non-technical human validates the identity, to a Registrar. A non-technical human validates the identity,
for example by comparing the identity displayed by the registrar for example by comparing the identity displayed by the registrar
(for example using a smartphone app) with the identity shown on (for example using a smartphone app) with the identity shown on
the packaging of the device. Acceptance may be triggered by a the packaging of the device. Acceptance may be triggered by a
click on a smartphone app "accept this device", or by other forms click on a smartphone app "accept this device", or by other forms
of pairing. See also [I-D.behringer-homenet-trust-bootstrap] for of pairing. See also [I-D.behringer-homenet-trust-bootstrap] for
how the approach could work in a homenet. how the approach could work in a homenet.
3. Whitelist acceptance: In larger networks, neither of the previous 3. Whitelist acceptance: In larger networks, neither of the previous
approaches is acceptable. Default acceptance is not secure, and approaches is acceptable. Default acceptance is not secure, and
a manual per device methods do not scale. Here, the registrar is a manual per device methods do not scale. Here, the registrar is
skipping to change at page 27, line 35 skipping to change at page 28, line 9
to securely establish a connection between devices and central to securely establish a connection between devices and central
control functions. Also autonomic transactions can use the domain control functions. Also autonomic transactions can use the domain
certificates to authenticate and/or encrypt direct interactions certificates to authenticate and/or encrypt direct interactions
between devices. The usage of the domain certificates is outside between devices. The usage of the domain certificates is outside
scope for this document. scope for this document.
5. Protocol Details 5. Protocol Details
A bootstrapping protocol could be implemented as an independent A bootstrapping protocol could be implemented as an independent
protocol from EST, but for simplicity and to reduce the number of TLS protocol from EST, but for simplicity and to reduce the number of TLS
connections and crypto operations required on the New Entity, it is connections and crypto operations required on the Pledge, it is
described specifically as extensions to EST. These extensions MUST described specifically as extensions to EST. These extensions MUST
be supported by the Registrar EST server within the same .well-known be supported by the Registrar EST server within the same .well-known
URI tree as the existing EST URIs as described in [RFC7030] section URI tree as the existing EST URIs as described in [RFC7030] section
3.2.2. 3.2.2.
The new entity establishes a TLS connection with the Registrar The Pledge establishes a TLS connection with the Registrar through
through the circuit proxy (see Section 3.2) but the TLS connection is the circuit proxy (see Section 3.2) but the TLS connection is with
with the Registar; so for this section the "New Entity" is the TLS the Registar; so for this section the "Pledge" is the TLS client and
client and the "Registrar" is the TLS server. the "Registrar" is the TLS server.
Establishment of the TLS connection for bootstrapping is as specified Establishment of the TLS connection for bootstrapping is as specified
for EST [RFC7030]. In particular server identity and client identity for EST [RFC7030]. In particular server identity and client identity
are as described in EST [RFC7030] section 3.3. In EST [RFC7030] are as described in EST [RFC7030] section 3.3. In EST [RFC7030]
provisional server authentication for bootstrapping is described in provisional server authentication for bootstrapping is described in
section 4.1.1 wherein EST clients can "engage a human user to section 4.1.1 wherein EST clients can "engage a human user to
authorize the CA certificate using out-of-band data such as a CA authorize the CA certificate using out-of-band data such as a CA
certificate" or wherein a human user configures the URI of the EST certificate" or wherein a human user configures the URI of the EST
server for Implicit TA based authentication. As described in this server for Implicit TA based authentication. As described in this
document, Section 5.3.1, a new method of bootstrapping now provides a document, Section 5.3.1, a new method of bootstrapping now provides a
completely automating method of bootstrapping PKI. completely automating method of bootstrapping PKI.
The extensions for the New Entity client are as follows: The extensions for the Pledge client are as follows:
o The New Entity provisionally accept the EST server certificate o The Pledge provisionally accept the EST server certificate during
during the TLS handshake as detailed in Section 5.3.1. the TLS handshake as detailed in Section 5.3.1.
o The New Entity requests and validates the Audit Token as described o The Pledge requests and validates the Audit Voucher as described
below. At this point the New Entity has sufficient information to below. At this point the Pledge has sufficient information to
validate domain credentials. validate domain credentials.
o The New Entity calls the EST defined /cacerts method to obtain the o The Pledge calls the EST defined /cacerts method to obtain the
current CA certificate. These are validated using the Audit current CA certificate. These are validated using the Audit
Token. Voucher.
o The New Entity completes bootstrapping as detailed in EST section o The Pledge completes bootstrapping as detailed in EST section
4.1.1. 4.1.1.
In order to obtain a validated Audit Token and Audit Log the In order to obtain a validated Audit Voucher and Audit Log a
Registrar contacts the MASA service Service using REST calls: Registrar contacts the MASA service Service using REST calls:
+-----------+ +----------+ +-----------+ +----------+ +-----------+ +----------+ +-----------+ +----------+
| New | | Circuit | | | | | | New | | Circuit | | | | |
| Entity | | Proxy | | Registrar | | Vendor | | Entity | | Proxy | | Registrar | | Vendor |
| | | | | | | | | | | | | | | |
++----------+ +--+-------+ +-----+-----+ +--------+-+ ++----------+ +--+-------+ +-----+-----+ +--------+-+
| | | | | | | |
| | | | | | | |
| TLS hello | TLS hello | | | TLS hello | TLS hello | |
Establish +---------------C---------------> | Establish +---------------C---------------> |
TLS | | | | TLS | | | |
connection | | Server Cert | | connection | | Server Cert | |
<---------------C---------------+ | <---------------C---------------+ |
| Client Cert | | | | Client Cert | | |
+---------------C---------------> | +---------------C---------------> |
| | | | | | | |
HTTP REST | POST /requestaudittoken | | HTTP REST | POST /requestvoucher | |
Data +--------------------nonce------> | Data +--------------------nonce------> |
| . | /requestaudittoken | . | /requestvoucher|
| . +----------------> | . +---------------->
| <----------------+ | <----------------+
| | /requestauditlog | | /requestlog |
| +----------------> | +---------------->
| audit token or owner voucher <----------------+ | voucher <----------------+
<-------------------------------+ | <-------------------------------+ |
| (optional config information) | | | (optional config information) | |
| . | | | . | |
| . | | | . | |
Figure 5 Figure 5
In some use cases the Registrar may need to contact the Vendor in In some use cases the Registrar may need to contact the Vendor in
advanced, for example when the target network is air-gapped. The advanced, for example when the target network is air-gapped. The
nonceless request format is provided for this and the resulting flow nonceless request format is provided for this and the resulting flow
is slightly different. The security differences associated with not is slightly different. The security differences associated with not
knowing the nonce are discussed below: knowing the nonce are discussed below:
+-----------+ +----------+ +-----------+ +----------+ +-----------+ +----------+ +-----------+ +----------+
| New | | Circuit | | | | | | New | | Circuit | | | | |
| Entity | | Proxy | | Registrar | | Vendor | | Entity | | Proxy | | Registrar | | Vendor |
| | | | | | | | | | | | | | | |
++----------+ +--+-------+ +-----+-----+ +--------+-+ ++----------+ +--+-------+ +-----+-----+ +--------+-+
| | | | | | | |
| | | | | | | |
| | | /requestaudittoken | | | /requestvoucher|
| | (nonce +----------------> | | (nonce +---------------->
| | unknown) <----------------+ | | unknown) <----------------+
| | | /requestauditlog | | | /requestlog |
| | +----------------> | | +---------------->
| | <----------------+ | | <----------------+
| TLS hello | TLS hello | | | TLS hello | TLS hello | |
Establish +---------------C---------------> | Establish +---------------C---------------> |
TLS | | | | TLS | | | |
connection | | Server Cert | | connection | | Server Cert | |
<---------------C---------------+ | <---------------C---------------+ |
| Client Cert | | | | Client Cert | | |
| | | | | | | |
HTTP REST | POST /requestaudittoken | | HTTP REST | POST /requestvoucher | |
Data +----------------------nonce----> (discard | Data +----------------------nonce----> (discard |
| audit token or owner Voucher | nonce) | | voucher | nonce) |
<-------------------------------+ | <-------------------------------+ |
| (optional config information) | | | (optional config information) | |
| . | | | . | |
| . | | | . | |
Figure 6 Figure 6
The extensions for the Registrar server are as follows: The extensions for a Registrar server are as follows:
o The Registrar requests and validates the Audit Token from the o The Registrar requests and validates the Audit Voucher from the
vendor authorized MASA service. vendor authorized MASA service.
o The Registrar forwards the Audit Token to the New Entity when o The Registrar forwards the Audit Voucher to the Pledge when
requested. requested.
o The Registar performs log verifications in addition to local o The Registar performs log verifications in addition to local
authorization checks before accepting the New Entity device. authorization checks before accepting the Pledge device.
5.1. Request Audit Token from the Registrar 5.1. Request Voucher from the Registrar
When the New Entity reaches the EST section 4.1.1 "Bootstrap When the Pledge bootstraps it makes a request for a Voucher from a
Distribution of CA Certificates" state but wishes to proceed in a Registrar.
fully automated fashion it makes a request for a MASA authorization
token from the Registrar.
This is done with an HTTPS POST using the operation path value of This is done with an HTTPS POST using the operation path value of
"/requestaudittoken". "/requestvoucher".
The request format is JSON object containing a 64bit nonce generated The request format is JSON object containing a 64bit nonce generated
by the client for each request. This nonce MUST be a by the client for each request. This nonce MUST be a
cryptographically strong random or pseudo-random number that can not cryptographically strong random or pseudo-random number that can not
be easily predicted. The nonce MUST NOT be reused for multiple be easily predicted. The nonce MUST NOT be reused for multiple
attempts to join a network domain. The nonce assures the New Entity attempts to join a network domain. The nonce assures the Pledge that
that the audit token response is associated with this bootstrapping the Audit Voucher response is associated with this bootstrapping
attempt and is not a replay. attempt and is not a replay.
Request media type: application/auditnonce Request media type: application/auditnonce
Request format: a JSON file with the following: Request format: a JSON file with the following:
{ {
"version":"1", "version":"1",
"nonce":"<64bit nonce value>", "nonce":"<64bit nonce value>",
} }
[[EDNOTE: Even if the nonce was signed it would provide no defense [[EDNOTE: Even if the nonce was signed it would provide no defense
against rogue registrars; although it would assure the MASA that a against rogue registrars; although it would assure the MASA that a
certified new entity exists. To protect against rogue registrars a certified Pledge exists. To protect against rogue registrars a nonce
nonce component generated by the MASA (a new round trip) would be component generated by the MASA (a new round trip) would be
required). Instead this is addressed by requiring MASA & Registrar required). Instead this is addressed by requiring MASA & Registrar
authentications but it is worth exploring additional protections. authentications but it is worth exploring additional protections.
This to be explored more at IETF96.]] This to be explored more at IETF96.]]
The Registrar validates the client identity as described in EST The Registrar validates the client identity as described in EST
[RFC7030] section 3.3.2. The registrar performs authorization as [RFC7030] section 3.3.2. The registrar performs authorization as
detailed in Section 3.3.2. If authorization is successful the detailed in Section 3.3.2. If authorization is successful the
Registrar obtains an Audit Token from the MASA service (see Registrar obtains an Voucher from the MASA service (see Section 5.2).
Section 5.2).
The received MASA authorization token is returned to the New Entity. The received Voucher is forwarded to the Pledge.
As indicated in EST [RFC7030] the bootstrapping server can redirect As indicated in EST [RFC7030] the bootstrapping server can redirect
the client to an alternate server. If the New Entity authenticated the client to an alternate server. If the Pledge authenticated a
the Registrar using the well known URI method then the New Entity Registrar using the well known URI method then the Pledge MUST follow
MUST follow the redirect automatically and authenticate the new the redirect automatically and authenticate the new Registrar against
Registrar against the redirect URI provided. If the New Entity had the redirect URI provided. If the Pledge had not yet authenticated a
not yet authenticated the Registrar because it was discovered and was Registrar because it was discovered and was not a known-to-be-valid
not a known-to-be-valid URI then the new Registrar must be URI then the new Registrar must be authenticated using one of the two
authenticated using one of the two autonomic methods described in autonomic methods described in this document. Similarly the Registar
this document. Similarly the Registar MAY respond with an HTTP 202 MAY respond with an HTTP 202 ("the request has been accepted for
("the request has been accepted for processing, but the processing processing, but the processing has not been completed") as described
has not been completed") as described in EST [RFC7030] section 4.2.3. in EST [RFC7030] section 4.2.3.
Recall that during this communication with the Registar the TLS Recall that during this communication with the Registar the TLS
authentication is only provisional. The New Entity client MUST authentication is only provisional. The Pledge client MUST handle
handle all data from the Registrar with upmost care. In particular all data from the Registrar with upmost care. In particular the
the New Entity MUST only allow a single redirection and MUST only Pledge MUST only allow a single redirection and MUST only support a
support a delay of five seconds before declaring the Registrar a delay of five seconds before declaring the Registrar a failure and
failure and moving on to the next discovered Registrar. As detailed moving on to the next discovered Registrar. As detailed in
in Section 3.1.1 if no suitable Registrar is found the New Entity Section 3.1.1 if no suitable Registrar is found the Pledge restarts
restarts the state machine and tries again. So a Registrar that is the state machine and tries again. So a Registrar that is unable to
unable to complete the transaction the first time will have future complete the transaction the first time will have future chances.
chances.
5.2. Request Audit Token from MASA 5.2. Request Voucher from MASA
The Registrar requests the Audit Token from the MASA service using a A Registrar requests a Voucher from the MASA service using a REST
REST interface. For simplicity this is defined as an optional EST interface. For simplicity this is defined as an optional EST message
message between the Registrar and an EST server running on the MASA between a Registrar and an EST server running on the MASA service
service although the Registrar is not required to make use of any although the Registrar is not required to make use of any other EST
other EST functionality when communicating with the MASA service. functionality when communicating with the MASA service. (The MASA
(The MASA service MUST properly reject any EST functionality requests service MUST properly reject any EST functionality requests it does
it does not wish to service; a requirement that holds for any REST not wish to service; a requirement that holds for any REST
interface). interface).
This is done with an HTTP POST using the operation path value of This is done with an HTTP POST using the operation path value of
"/requestaudittoken". "/requestvoucher".
The request format is a JSON object optionally containing the nonce The request format is a JSON object optionally containing the nonce
value (as obtained from the bootstrap request) and the IEEE 802.1AR value (as obtained from the bootstrap request) and the X.509 IDevID
identity of the device as a serial number (the full certificate is extracted serial number (the full certificate is not needed and no
not needed and no proof-of-possession information for the device proof-of-possession information for the device identity is included).
identity is included). The AuthorityKeyIdentifier value from the The AuthorityKeyIdentifier value from the certificate is included to
certificate is included to ensure a statistically unique identity. ensure a statistically unique identity. The Pledge's serial number
The New Entity's serial number is extracted from the IEEE 802.1AR is extracted from the X.509 IDevID subject name id-at-serialNumber or
subject name id-at-serialNumber or it is the base64 encoded RFC4108 it is the base64 encoded RFC4108 hardwareModuleName hwSerialNum:
hardwareModuleName hwSerialNum:
{ {
"version":"1", "version":"1",
"nonce":"<64bit nonce value>", "nonce":"<64bit nonce value>",
"IDevIDAuthorityKeyIdentifier":"<base64 encoded keyIdentifier">, "IDevIDAuthorityKeyIdentifier":"<base64 encoded keyIdentifier">,
"DevIDSerialNumber":"<id-at-serialNumber or base64 encoded "DevIDSerialNumber":"<id-at-serialNumber or base64 encoded
hardwareModuleName hwSerialNum>", hardwareModuleName hwSerialNum>",
} }
The Registrar MAY exclude the nonce from the request. Doing so A Registrar MAY exclude the nonce from the request. Doing so allows
allows the Registrar to request an authorization token when the New the Registrar to request a Voucher when the Pledge is not online, or
Entity is not online, or when the target bootstrapping environment is when the target bootstrapping environment is not on the same network
not on the same network as the MASA server (this requires the as the MASA server (this requires the Registrar to learn the
Registrar to learn the appropriate DevIDSerialNumber field from the appropriate DevIDSerialNumber field from the physical device labeling
physical device labeling or from the sales channel -- how this occurs or from the sales channel -- how this occurs is out-of-scope of this
is out-of-scope of this document). If a nonce is not provided the document). If a nonce is not provided the MASA server MUST
MASA server MUST authenticate the client as described in EST authenticate the client as described in EST [RFC7030] section 3.3.2
[RFC7030] section 3.3.2 to reduce the risk of DDoS attacks. The to reduce the risk of DDoS attacks. A Registrar performs
registrar performs authorization as detailed in Section 3.3.2. If authorization as detailed in Section 3.3.2. If authorization is
authorization is successful the Registrar obtains an Audit Token from successful the Registrar obtains an Voucher from the MASA service
the MASA service (see Section 5.2). (see Section 5.2).
The JSON message information is encapsulated in a [RFC5652] Signed- The JSON message information is encapsulated in a [RFC5652] Signed-
data that is signed by the Registrar. The entire certificate chain, data that is signed by the Registrar. The entire certificate chain,
up to and including the Domain CA, MUST be included in the up to and including the Domain CA, MUST be included in the
CertificateSet structure. The MASA service checks the internal CertificateSet structure. The MASA service checks the internal
consistency of the CMS but does not authenticate the domain identity consistency of the CMS but does not authenticate the domain identity
information. The domain is not know to the MASA server in advance information. The domain is not know to the MASA server in advance
and a shared trust anchor is not implied. The MASA server MUST and a shared trust anchor is not implied. The MASA server MUST
verify that the CMS is signed by a Registrar certificate (by checking verify that the CMS is signed by a Registrar certificate (by checking
for the cmc-idRA field) that was issued by a the root certificate for the cmc-idRA field) that was issued by a the root certificate
included in the CMS. This ensures that the Registrar making the included in the CMS. This ensures that the Registrar making the
claim is an authorized Registrar of the unauthenticated domain. The claim is an authorized Registrar of the unauthenticated domain. The
EST style client authentication (TLS and HTTP) is used to provide a EST style client authentication (TLS and HTTP) is used to provide a
DDoS prevention strategy. DDoS prevention strategy.
The domain ID (e.g. hash of the public key of the domain) is The root certificate is extracted and used to populate the Audit
extracted from the root certificate and is used to populate the MASA Voucher. The domain ID (e.g. hash of the public key of the domain)
authorization token and to update the audit log. is extracted from the root certificate and is used to update the
audit log.
5.3. Audit Token Response 5.3. Audit Voucher Response
The authorization token response to requests from the device and The voucher response to requests from the device and requests from a
requests from the Registrar are in the same format. The Registrar Registrar are in the same format. A Registrar either caches prior
either caches prior MASA responses or dynamically requests a new MASA responses or dynamically requests a new Voucher based on local
Audit Token based on local policy. policy.
If the the join operation is successful, the server response MUST If the the join operation is successful, the server response MUST
contain an HTTP 200 response code with a content-type of contain an HTTP 200 response code with a content-type of
"application/authorization-token". The server MUST answer with a "application/authorizationvoucher". The server MUST answer with a
suitable 4xx or 5xx HTTP [RFC2616] error code when a problem occurs. suitable 4xx or 5xx HTTP [RFC2616] error code when a problem occurs.
The response data from the MASA server MUST be a plaintext human- The response data from the MASA server MUST be a plaintext human-
readable error message containing explanatory information describing readable error message containing explanatory information describing
why the request was rejected. why the request was rejected.
The authorization token consists of the nonce, if supplied, the The Audit Voucher consists of the nonce, if supplied, the serial
serial number information identifying the device and the domain CA number information identifying the device and the domain CA
certificate extracted from the request: certificate extracted from the request:
{ {
"version":"1", "version":"1",
"nonce":"<64bit nonce value>", "nonce":"<64bit nonce value>",
"IDevIDAuthorityKeyIdentifier":"<base64 encoded keyIdentifier>", "IDevIDAuthorityKeyIdentifier":"<base64 encoded keyIdentifier>",
"DevIDSerialNumber":"<id-at-serialNumber>", "DevIDSerialNumber":"<id-at-serialNumber>",
"domainCAcert":"<the base64 encoded domain CA's certificate>" "domainCAcert":"<the base64 encoded domain CA's certificate>"
} }
The Audit Voucher response is encapsulated in a [RFC5652] Signed-data
The audit token response is encapsulated in a [RFC5652] Signed-data that is signed by the MASA server. The Pledge verifies this signed
that is signed by the MASA server. The New Entity verifies this message using the manufacturer installed trust anchor assocaited with
signed message using the IEEE 802.1AR manufacturer installed trust the X.509 IDevID. [[EDNOTE: As detailed in netconf-zerotouch this
anchor. might be a distinct trust anchor rather than re-using the trust
anchor for the IDevID. This concept will need to be detailed in this
document as well.]]
[[EDNOTE: Using CMS is consistent with the alignment of this [[EDNOTE: Using CMS is consistent with the alignment of this
bootstrapping document with EST, a PKIX enrollment protocol that bootstrapping document with EST, a PKIX enrollment protocol that
includes Certificate Management over CMS. An alternative format includes Certificate Management over CMS. An alternative format
would be the RFC7515 JSON Web Signature (JWS), which would allow would be the RFC7515 JSON Web Signature (JWS), which would allow
clients that do not use fullCMC messages to avoid CMS entirely. Use clients that do not use fullCMC messages to avoid CMS entirely. Use
of JWS would likely include a discussion of CBOR in order ensure the of JWS would likely include a discussion of CBOR in order ensure the
base64 expansions of the certs and signatures within the JWS message base64 expansions of the certs and signatures within the JWS message
are of minimal size -- it is not yet clear to this author how that are of minimal size -- it is not yet clear to this author how that
would work out]] would work out]]
The 'domainCAcert' element of this message contains the domain CA's The 'domainCAcert' element of this message contains the domain CA's
public key. This is specific to bootstrapping a public key public key. This is specific to bootstrapping a public key
infrastructure. To support bootstrapping other key infrastructures infrastructure. To support bootstrapping other key infrastructures
additional domain identity types might be defined in the future. additional domain identity types might be defined in the future.
Clients MUST be prepared to ignore additional fields they do not Clients MUST be prepared to ignore additional fields they do not
recognize. Clients MUST be prepared to parse and fail gracefully recognize. Clients MUST be prepared to parse and fail gracefully
from an audit token response that does not contain a 'domainCAcert' from an Audit Voucher response that does not contain a 'domainCAcert'
field at all. field at all.
To minimize the size of the audit token response message the To minimize the size of the Audit Voucher response message the
domainCAcert is not a complete distribution of the EST section 4.1.3 domainCAcert is not a complete distribution of the EST section 4.1.3
CA Certificate Response. CA Certificate Response.
The New Entity installs the domainCAcert trust anchor. As indicated The Pledge installs the domainCAcert trust anchor. As indicated in
in Section 3.1.2 the newly installed trust anchor is used as an EST Section 3.1.2 the newly installed trust anchor is used as an EST
RFC7030 Explicit Trust Anchor. The New Entity MUST use the RFC7030 Explicit Trust Anchor. The Pledge MUST use the domainCAcert
domainCAcert trust anchor to immediately validate the currently trust anchor to immediately validate the currently provisional TLS
provisional TLS connection to the Registrar. connection to a Registrar.
5.3.1. Completing authentication of Provisional TLS connection 5.3.1. Completing authentication of Provisional TLS connection
If the Registrar's credential can not be verified using the If a Registrar's credential can not be verified using the
domainCAcert trust anchor the TLS connection is immediately discarded domainCAcert trust anchor the TLS connection is immediately discarded
and the New Entity abandons attempts to bootstrap with this and the Pledge abandons attempts to bootstrap with this discovered
discovered registrar. registrar.
The following behaviors on the Registrar and New Entity are in The following behaviors on a Registrar and Pledge are in addition to
addition to normal PKIX operations: normal PKIX operations:
o The EST server MUST use a certificate that chains to the o The EST server MUST use a certificate that chains to the
domainCAcert. This means that when the EST server obtains renewed domainCAcert. This means that when the EST server obtains renewed
credentials the credentials included in the Section 5.2 request credentials the credentials included in the Section 5.2 request
match the chain used in the current provisional TLS connection. match the chain used in the current provisional TLS connection.
o The New Entity PKIX path validation of the Registrar validity o The Pledge PKIX path validation of a Registrar validity period
period information is as described in Section 3.1.5. information is as described in Section 3.1.5.
Because the domainCAcert trust anchor is installed as an Explicit Because the domainCAcert trust anchor is installed as an Explicit
Trust Anchor it can be used to authenticate any dynamically Trust Anchor it can be used to authenticate any dynamically
discovered EST server that contain the id-kp-cmcRA extended key usage discovered EST server that contain the id-kp-cmcRA extended key usage
extension as detailed in EST RFC7030 section 3.6.1; but to reduce extension as detailed in EST RFC7030 section 3.6.1; but to reduce
system complexity the New Entity SHOULD avoid additional discovery system complexity the Pledge SHOULD avoid additional discovery
operations. Instead the New entity SHOULD communicate directly with operations. Instead the Pledge SHOULD communicate directly with the
the Registrar as the EST server to complete PKI local certificate Registrar as the EST server to complete PKI local certificate
enrollment. Additionally the New Entity SHOULD use the existing TLS enrollment. Additionally the Pledge SHOULD use the existing TLS
connection to proceed with EST enrollment, thus reducing the total connection to proceed with EST enrollment, thus reducing the total
amount of cryptographic and round trip operations required during amount of cryptographic and round trip operations required during
bootstrapping. [[EDNOTE: It is reasonable to mandate that the bootstrapping. [[EDNOTE: It is reasonable to mandate that the
existing TLS connection be re-used? e.g. MUST >> SHOULD?]] existing TLS connection be re-used? e.g. MUST >> SHOULD?]]
5.4. Audit Token Status Telemetry 5.4. Voucher Status Telemetry
For automated bootstrapping of devices the adminstrative elements For automated bootstrapping of devices the adminstrative elements
providing bootstrapping also provide indications to the system providing bootstrapping also provide indications to the system
administrators concerning device lifecycle status. To facilitate administrators concerning device lifecycle status. To facilitate
this those elements need telemetry information concerning the this those elements need telemetry information concerning the
device's status. device's status.
To indicate New Entity status regarding the audit token the client To indicate Pledge status regarding the Audit Voucher the client
SHOULD post a status message. SHOULD post a status message.
The client HTTP POSTs the following to the server at the EST well The client HTTP POSTs the following to the server at the EST well
known URI /requestaudittoken_status. The Status field indicates if known URI /voucher_status. The Status field indicates if the Voucher
the audit token was acceptable. If it was not acceptable the Reason was acceptable. If it was not acceptable the Reason string indicates
string indicates why. In the failure case this message is being sent why. In the failure case this message is being sent to an
to an unauthenticated, potentially malicious Registrar and therefore unauthenticated, potentially malicious Registrar and therefore the
the Reason string SHOULD NOT provide information beneficial to an Reason string SHOULD NOT provide information beneficial to an
attacker. The operational benefit of this telemetry information is attacker. The operational benefit of this telemetry information is
balanced against the operational costs of not recording that an audit balanced against the operational costs of not recording that an
token was ignored by a client the registar expected to continue Voucher was ignored by a client the registar expected to continue
joining the domain. joining the domain.
{ {
"version":"1", "version":"1",
"Status":FALSE /* TRUE=Success, FALSE=Fail" "Status":FALSE /* TRUE=Success, FALSE=Fail"
"Reason":"Informative human readable message" "Reason":"Informative human readable message"
} }
The server SHOULD respond with an HTTP 200 but MAY simply fail with The server SHOULD respond with an HTTP 200 but MAY simply fail with
an HTTP 404 error. The client ignores any response. Within the an HTTP 404 error. The client ignores any response. Within the
server logs the server SHOULD capture this telemetry information. server logs the server SHOULD capture this telemetry information.
5.5. MASA authorization log Request 5.5. MASA authorization log Request
A registrar requests the MASA authorization log from the MASA service A registrar requests the MASA authorization log from the MASA service
using this EST extension. using this EST extension.
This is done with an HTTP GET using the operation path value of This is done with an HTTP GET using the operation path value of
skipping to change at page 36, line 21 skipping to change at page 36, line 14
The server SHOULD respond with an HTTP 200 but MAY simply fail with The server SHOULD respond with an HTTP 200 but MAY simply fail with
an HTTP 404 error. The client ignores any response. Within the an HTTP 404 error. The client ignores any response. Within the
server logs the server SHOULD capture this telemetry information. server logs the server SHOULD capture this telemetry information.
5.5. MASA authorization log Request 5.5. MASA authorization log Request
A registrar requests the MASA authorization log from the MASA service A registrar requests the MASA authorization log from the MASA service
using this EST extension. using this EST extension.
This is done with an HTTP GET using the operation path value of This is done with an HTTP GET using the operation path value of
"/requestMASAlog". "/requestauditlog".
The client HTTP POSTs the same Audit Token Request as for requesting The client HTTP POSTs the same Voucher Request as for requesting an
an audit token but now posts it the /requestMASAlog URI instead. The audit token but now posts it to the /requestauditlog URI instead.
IDevIDAuthorityKeyIdentifier and DevIDSerialNumber informs the MASA The IDevIDAuthorityKeyIdentifier and DevIDSerialNumber informs the
server which log is requested so the appropriate log can be prepared MASA server which log is requested so the appropriate log can be
for the response. prepared for the response.
5.6. MASA authorization log Response 5.6. MASA authorization log Response
A log data file is returned consisting of all log entries. For A log data file is returned consisting of all log entries. For
example: example:
{ {
"version":"1", "version":"1",
"events":[ "events":[
{ {
"date":"<date/time of the entry>", "date":"<date/time of the entry>",
"domainID":"<domainID as extracted from the domain CA certificate "domainID":"<domainID as extracted from the domain CA certificate
within the CMS of the audit token request>", within the CMS of the audit voucher request>",
"nonce":"<any nonce if supplied (or the exact string 'NULL')>" "nonce":"<any nonce if supplied (or the exact string 'NULL')>"
}, },
{ {
"date":"<date/time of the entry>", "date":"<date/time of the entry>",
"domainID":"<domainID as extracted from the domain CA certificate "domainID":"<domainID as extracted from the domain CA certificate
within the CMS of the audit token request>", within the CMS of the audit voucher request>",
"nonce":"<any nonce if supplied (or the exact string 'NULL')>" "nonce":"<any nonce if supplied (or the exact string 'NULL')>"
} }
] ]
} }
Distribution of a large log is less than ideal. This structure can Distribution of a large log is less than ideal. This structure can
be optimized as follows: All nonce-less entries for the same domainID be optimized as follows: All nonce-less entries for the same domainID
MAY be condensed into the single most recent nonceless entry. MAY be condensed into the single most recent nonceless entry.
The Registrar uses this log information to make an informed decision A Registrar uses this log information to make an informed decision
regarding the continued bootstrapping of the New Entity. For example regarding the continued bootstrapping of the Pledge. For example if
if the log includes unexpected domainIDs this is indicative of the log includes unexpected domainIDs this is indicative of
problematic imprints by the new entity. If the log includes nonce- problematic imprints by the Pledge. If the log includes nonce-less
less entries this is indicative of the permanent ability for the entries this is indicative of the permanent ability for the indicated
indicated domain to trigger a reset of the device and take over domain to trigger a reset of the device and take over management of
management of it. Equipment that is purchased pre-owned can be it. Equipment that is purchased pre-owned can be expected to have an
expected to have an extensive history. extensive history.
Log entries containing the Domain's ID can be compared against local Log entries containing the Domain's ID can be compared against local
history logs in search of discrepancies. history logs in search of discrepancies.
5.7. EST Integration for PKI bootstrapping 5.7. EST Integration for PKI bootstrapping
The prior sections describe EST extensions necessary to enable fully The prior sections describe EST extensions necessary to enable fully
automated bootstrapping. Although the audit token request/response automated bootstrapping. Although the Audit Voucher request/response
structure members IDevIDAuthorityKeyIdentifier and DevIDSerialNumber structure members IDevIDAuthorityKeyIdentifier and DevIDSerialNumber
are specific to PKI bootstrapping these are the only PKI specific are specific to PKI bootstrapping these are the only PKI specific
aspects of the extensions and future work might replace them with aspects of the extensions and future work might replace them with
non-PKI structures. non-PKI structures.
The prior sections provide functionality for the New Entity to obtain The prior sections provide functionality for the Pledge to obtain a
a trust anchor representative of the Domain. The following section trust anchor representative of the Domain. The following section
describe using EST to obtain a locally issued PKI certificate. The describe using EST to obtain a locally issued PKI certificate. The
New Entity MAY perform alternative enrollment methods or proceed to Pledge SHOULD leverage the discovered Registrar to proceed with
use its IDevID credential indefinately, but those that leverage the certificate enrollment and, if they do, MUST implement the EST
discovered Registrar to proceed with certificate enrollment MUST options described in this section. The Pledge MAY perform
implement the following EST choices. alternative enrollment methods including discovering an alternate EST
server, or proceed to use its IDevID credential indefinitely.
5.7.1. EST Distribution of CA Certificates 5.7.1. EST Distribution of CA Certificates
The New Entity MUST request the full EST Distribution of CA The Pledge MUST request the full EST Distribution of CA Certificates
Certificates message. See RFC7030, section 4.1. message. See RFC7030, section 4.1.
This ensures that the New Entity has the complete set of current CA This ensures that the Pledge has the complete set of current CA
certificates beyond the domainCAcert (see Section 5.3 for a certificates beyond the domainCAcert (see Section 5.3 for a
discussion of the limitations). Although these restrictions are discussion of the limitations). Although these restrictions are
acceptable for the Registrar integrated with initial bootstrapping acceptable for a Registrar integrated with initial bootstrapping they
they are not appropriate for ongoing PKIX end entity certificate are not appropriate for ongoing PKIX end entity certificate
validation. validation.
5.7.2. EST CSR Attributes 5.7.2. EST CSR Attributes
Automated bootstrapping occurs without local administrative Automated bootstrapping occurs without local administrative
configuration of the New Entity. In some deployments its plausible configuration of the Pledge. In some deployments its plausible that
that the New Entity generates a certificate request containing only the Pledge generates a certificate request containing only identity
identity information known to the New Entity (essentially the IDevID information known to the Pledge (essentially the IDevID information)
information) and ultimately receives a certificate containing domain and ultimately receives a certificate containing domain specific
specific identity information. Conceptually the CA has complete identity information. Conceptually the CA has complete control over
control over all fields issued in the end entity certificate. all fields issued in the end entity certificate. Realistically this
Realistically this is operationally difficult with the current status is operationally difficult with the current status of PKI certificate
of PKI certificate authority deployments where the CSR is submitted authority deployments where the CSR is submitted to the CA via a
to the CA via a number of non-standard protocols. number of non-standard protocols.
To alleviate operational difficulty the New Entity MUST request the To alleviate operational difficulty the Pledge MUST request the EST
EST "CSR Attributes" from the EST server. This allows the local "CSR Attributes" from the EST server. This allows the local
infrastructure to inform the New Entity of the proper fields to infrastructure to inform the Pledge of the proper fields to include
include in the generated CSR. in the generated CSR.
[[EDNOTE: The following is specific to anima purposes and should be [[EDNOTE: The following is specific to anima purposes and should be
moved to an appropriate anima document so as to keep bootstrapping as moved to an appropriate anima document so as to keep bootstrapping as
generic as possible: What we want are a 'domain name' stored in [TBD] generic as possible: What we want are a 'domain name' stored in [TBD]
and an 'ACP IPv6 address' stored in the iPAddress field as specified and an 'ACP IPv6 address' stored in the iPAddress field as specified
in RFC5208 s4.2.1.6. ref ACP draft where certificate verification in RFC5208 s4.2.1.6. ref ACP draft where certificate verification
[TBD]. These should go into the subjectaltname in the [TBD] [TBD]. These should go into the subjectaltname in the [TBD]
fields.]]. If the hardwareModuleName in the IDevID is populated then fields.]]. If the hardwareModuleName in the IDevID is populated then
it SHOULD by default be propagated to the LDevID along with the it SHOULD by default be propagated to the LDevID along with the
hwSerialNum. The registar SHOULD support local policy concerning hwSerialNum. The registar SHOULD support local policy concerning
skipping to change at page 38, line 44 skipping to change at page 38, line 34
The Registar MUST also confirm the resulting CSR is formatted as The Registar MUST also confirm the resulting CSR is formatted as
indicated before forwarding the request to a CA. If the Registar is indicated before forwarding the request to a CA. If the Registar is
communicating with the CA using a protocol like full CMC which communicating with the CA using a protocol like full CMC which
provides mechanisms to override the CSR attributes, then these provides mechanisms to override the CSR attributes, then these
mechanisms MAY be used even if the client ignores CSR Attribute mechanisms MAY be used even if the client ignores CSR Attribute
guidance. guidance.
5.7.3. EST Client Certificate Request 5.7.3. EST Client Certificate Request
The New Entity MUST request a new client certificate. See RFC7030, The Pledge MUST request a new client certificate. See RFC7030,
section 4.2. section 4.2.
5.7.4. Enrollment Status Telemetry 5.7.4. Enrollment Status Telemetry
For automated bootstrapping of devices the adminstrative elements For automated bootstrapping of devices the adminstrative elements
providing bootstrapping also provide indications to the system providing bootstrapping also provide indications to the system
administrators concerning device lifecycle status. This might administrators concerning device lifecycle status. This might
include information concerning attempted bootstrapping messages seen include information concerning attempted bootstrapping messages seen
by the client, MASA provides logs and status of credential by the client, MASA provides logs and status of credential
enrollment. The EST protocol assumes an end user and therefore does enrollment. The EST protocol assumes an end user and therefore does
skipping to change at page 39, line 46 skipping to change at page 39, line 38
recieved over an TLS session with a matching client certificate. recieved over an TLS session with a matching client certificate.
This allows for clients that wish to minimize their crypto operations This allows for clients that wish to minimize their crypto operations
to simpy POST this response without renegotiating the TLS session - to simpy POST this response without renegotiating the TLS session -
at the cost of the server not being able to accurately verify that at the cost of the server not being able to accurately verify that
enrollment was truly successful. enrollment was truly successful.
5.7.5. EST over CoAP 5.7.5. EST over CoAP
[[EDNOTE: In order to support smaller devices the above section on [[EDNOTE: In order to support smaller devices the above section on
Proxy behavior introduces mandatory to implement support for CoAP Proxy behavior introduces mandatory to implement support for CoAP
support by the Proxy. This implies similar support by the New Entity support by the Proxy. This implies similar support by the Pledge and
and Registrar and means that the EST protocol operation encapsulation Registrar and means that the EST protocol operation encapsulation
into CoAP needs to be described. EST is HTTP based and "CoaP is into CoAP needs to be described. EST is HTTP based and "CoaP is
designed to easily interface with HTTP for integration" [RFC7252]. designed to easily interface with HTTP for integration" [RFC7252].
Use of CoAP implies Datagram TLS (DTLS) wherever this document Use of CoAP implies Datagram TLS (DTLS) wherever this document
describes TLS handshake specifics. A complexity is that the large describes TLS handshake specifics. A complexity is that the large
message sizes necessary for bootstrapping will require support for message sizes necessary for bootstrapping will require support for
[draft-ietf-core-block].]] [draft-ietf-core-block].]]
6. Reduced security operational modes 6. Reduced security operational modes
A common requirement of bootstrapping is to support less secure A common requirement of bootstrapping is to support less secure
operational modes for support specific use cases. The following operational modes for support specific use cases. The following
sections detail specific ways that the New Entity, Registrar and MASA sections detail specific ways that the Pledge, Registrar and MASA can
can be configured to run in a less secure mode for the indicated be configured to run in a less secure mode for the indicated reasons.
reasons.
6.1. Trust Model 6.1. Trust Model
+--------+ +---------+ +------------+ +------------+ +--------+ +---------+ +------------+ +------------+
| New | | Circuit | | Domain | | Vendor | | New | | Circuit | | Domain | | Vendor |
| Entity | | Proxy | | Registrar | | Service | | Entity | | Proxy | | Registrar | | Service |
| | | | | | | (Internet | | | | | | | | (Internet |
+--------+ +---------+ +------------+ +------------+ +--------+ +---------+ +------------+ +------------+
Figure 7 Figure 7
New Entity: The New Entity could be compromised and providing an Pledge: The Pledge could be compromised and providing an attack
attack vector for malware. The entity is trusted to only imprint vector for malware. The entity is trusted to only imprint using
using secure methods described in this document. Additional secure methods described in this document. Additional endpoint
endpoint assessment techniques are RECOMMENDED but are out-of- assessment techniques are RECOMMENDED but are out-of-scope of this
scope of this document. document.
Proxy: Provides proxy functionalities but is not involved in Proxy: Provides proxy functionalities but is not involved in
security considerations. security considerations.
Registrar: When interacting with a MASA server the Registrar makes Registrar: When interacting with a MASA server a Registrar makes all
all decisions. When ownership vouchers are involved the Registrar decisions. When Ownership Vouchers are involved a Registrar is
is only a conduit and all security decisions are made on the only a conduit and all security decisions are made on the vendor
vendor service. service.
Vendor Service, MASA: This form of vendor service is trusted to Vendor Service, MASA: This form of vendor service is trusted to
accurately log all claim attempts and to provide authoritative log accurately log all claim attempts and to provide authoritative log
information to Registrars. The MASA does not know which devices information to Registrars. The MASA does not know which devices
are associated with which domains. These claims could be are associated with which domains. These claims could be
strengthened by using cryptographic log techniques to provide strengthened by using cryptographic log techniques to provide
append only, cryptographic assured, publicly auditable logs. append only, cryptographic assured, publicly auditable logs.
Current text provides only for a trusted vendor. Current text provides only for a trusted vendor.
Vendor Service, Ownership Validation: This form of vendor service is Vendor Service, Ownership Validation: This form of vendor service is
trusted to accurately know which device is owned by which domain. trusted to accurately know which device is owned by which domain.
6.2. New Entity security reductions 6.2. New Entity security reductions
Although New Entity can choose to run in less secure modes this is The Pledge MAY support "trust on first use" on physical interfaces
MUST NOT be the default state because it permanently degrades the but MUST NOT support "trust on first use" on network interfaces.
security for all other uses cases. This is because "trust on first use" permanently degrades the
security for all other use cases.
The device may have an operational mode where it skips Audit Token or The Pledge MAY have an operational mode where it skips Voucher
Ownership Voucher validation one time. For example if a physical validation one time. For example if a physical button is depressed
button is depressed during the bootstrapping operation. This can be during the bootstrapping operation. This can be useful if the vendor
useful if the vendor service is unavailable. This behavior SHOULD be service is unavailable. This behavior SHOULD be available via local
available via local configuration or physical presence methods to configuration or physical presence methods to ensure new entities can
ensure new entities can always be deployed even when autonomic always be deployed even when autonomic methods fail. This allows for
methods fail. This allows for unsecure imprint. unsecured imprint.
It is RECOMMENDED that this only be available if hardware assisted It is RECOMMENDED that this only be available if hardware assisted
NEA [RFC5209] is supported. NEA [RFC5209] is supported.
6.3. Registrar security reductions 6.3. Registrar security reductions
The Registrar can choose to accept devices using less secure methods. A Registrar can choose to accept devices using less secure methods.
These methods are acceptable when low security models are needed, as These methods are acceptable when low security models are needed, as
the security decisions are being made by the local administrator, but the security decisions are being made by the local administrator, but
they MUST NOT be the default behavior: they MUST NOT be the default behavior:
1. The registrar MAY choose to accept all devices, or all devices of 1. A registrar MAY choose to accept all devices, or all devices of a
a particular type, at the administrator's discretion. This could particular type, at the administrator's discretion. This could
occur when informing the Registrar of unique identifiers of new occur when informing all Registrars of unique identifiers of new
entities might be operationally difficult. entities might be operationally difficult.
2. The registrar MAY choose to accept devices that claim a unique 2. A registrar MAY choose to accept devices that claim a unique
identity without the benefit of authenticating that claimed identity without the benefit of authenticating that claimed
identity. This could occur when the New Entity does not include identity. This could occur when the Pledge does not include an
an IEEE 802.1AR factory installed credential. New Entities X.509 IDevID factory installed credential. New Entities without
without an IDevID credential MAY form the Section 5.1 request an IDevID credential MAY form the Section 5.1 request using the
using the Section 5.2 format to ensure the New Entity's serial Section 5.2 format to ensure the Pledge's serial number
number information is provided to the Registar (this includes the information is provided to the Registar (this includes the
IDevIDAuthorityKeyIdentifier value which would be statically IDevIDAuthorityKeyIdentifier value which would be statically
configured on the New Entity). The New Entity MAY refused to configured on the Pledge). The Pledge MAY refused to provide a
provide a TLS client certificate (as one is not available). The TLS client certificate (as one is not available). The Pledge
New Entity SHOULD support HTTP-based or certificate-less TLS SHOULD support HTTP-based or certificate-less TLS authentication
authentication as described in EST RFC7030 section 3.3.2. as described in EST RFC7030 section 3.3.2. A Registrar MUST NOT
accept unauthenticated New Entities unless it has been configured
to do so by an administrator that has verified that only expected
new entities can communicate with a Registrar (presumably via a
physically secured perimeter).
3. The registrar MAY request nonce-less Audit Tokens from the MASA 3. A Registrar MAY request nonce-less Audit Vouchers from the MASA
service. These tokens can then be transmitted to the Registrar service (by not including a nonce in the request). These Audit
and stored until they are needed during bootstrapping operations. Vouchers can then be transmitted to the Registrar and stored
This is for use cases where target network is protected by an air until they are needed during bootstrapping operations. This is
gap and therefore can not contact the MASA service during New for use cases where target network is protected by an air gap and
Entity deployment. therefore can not contact the MASA service during Pledge
deployment.
4. The registrar MAY ignore unrecognized nonce-less Audit Log 4. A registrar MAY ignore unrecognized nonce-less Audit Log entries.
entries. This could occur when used equipment is purchased with This could occur when used equipment is purchased with a valid
a valid history being deployed in air gap networks that required history being deployed in air gap networks that required
permanent Audit Tokens. permanent Audit Vouchers.
These modes are not available for devices that require a vendor These modes are not available for devices that require a vendor
Ownership Voucher. The methods vendors use to determine which Ownership Voucher. The methods vendors use to determine which
devices are owned by which domains is out-of-scope. devices are owned by which domains is out-of-scope.
6.4. MASA security reductions 6.4. MASA security reductions
Lower security modes chosen by the MASA service effect all device Lower security modes chosen by the MASA service effect all device
deployments unless bound to the specific device identities. In which deployments unless bound to the specific device identities. In which
case these modes can be provided as additional features for specific case these modes can be provided as additional features for specific
customers. The MASA service can choose to run in less secure modes customers. The MASA service can choose to run in less secure modes
by: by:
1. Not enforcing that a Nonce is in the Audit Token. This results 1. Not enforcing that a Nonce is in the Audit Voucher. This results
in distribution of Audit Tokens that never expire and in effect in distribution of Audit Voucher that never expire and in effect
makes the Domain an always trusted entity to the New Entity makes the Domain an always trusted entity to the Pledge during
during any subsequent bootstrapping attempts. That this occurred any subsequent bootstrapping attempts. That this occurred is
is captured in the log information so that the Domain registrar captured in the log information so that the Domain registrar can
can make appropriate security decisions when a New Entity joins make appropriate security decisions when a Pledge joins the
the Domain. This is useful to support use cases where Registrars Domain. This is useful to support use cases where Registrars
might not be online during actual device deployment. Because might not be online during actual device deployment. Because
this results in long lived Audit Tokens and do not require the this results in long lived Audit Voucher and do not require the
proof that the device is online this is only accepted when the proof that the device is online this is only accepted when the
Registrar is authenticated by the MASA server and authorized to Registrar is authenticated by the MASA server and authorized to
provide this functionality. The MASA server is RECOMMENDED to provide this functionality. The MASA server is RECOMMENDED to
use this functionality only in concert with Ownership Validation use this functionality only in concert with Ownership Validation
tracking. tracking.
2. Not verifying ownership before responding with an Audit Token. 2. Not verifying ownership before responding with an Audit Voucher.
This is expected to be a common operational model because doing This is expected to be a common operational model because doing
so relieves the vendor providing MASA services from having to so relieves the vendor providing MASA services from having to
tracking ownership during shipping and supply chain and allows tracking ownership during shipping and supply chain and allows
for a very low overhead MASA service. The Registrar uses the for a very low overhead MASA service. A Registrar uses the audit
audit log information as a defense in depth strategy to ensure log information as a defense in depth strategy to ensure that
that this does not occur unexpectedly (for example when this does not occur unexpectedly (for example when purchasing new
purchasing new equipment the Registrar would throw an error if equipment the Registrar would throw an error if any audit log
any audit log information is reported). information is reported).
7. Security Considerations 7. Security Considerations
In order to support a wide variety of use cases, devices can be In order to support a wide variety of use cases, devices can be
claimed by a registrar without proving possession of the device in claimed by a registrar without proving possession of the device in
question. This would result in a nonceless, and thus always valid, question. This would result in a nonceless, and thus always valid,
claim. Or would result in an invalid nonce being associated with a claim. Or would result in an invalid nonce being associated with a
claim. The MASA service is required to authenticate such Registrars claim. The MASA service is required to authenticate such Registrars
but no programmatic method is provided to ensure good behavior by the but no programmatic method is provided to ensure good behavior by the
MASA service. Nonceless entries into the audit log therefore MASA service. Nonceless entries into the audit log therefore
permanently reduce the value of a device because future Registrars, permanently reduce the value of a device because future Registrars,
during future bootstrap attempts, would now have to be configured during future bootstrap attempts, would now have to be configured
with policy to ignore previously (and potentially unknown) domains. with policy to ignore previously (and potentially unknown) domains.
Future registrars are recommended to take the audit history of a Future registrars are recommended to take the audit history of a
device into account when deciding to join such devices into their device into account when deciding to join such devices into their
network. If the MASA server were to have allowed a significantly network. If the MASA server were to have allowed a significantly
large number of claims this might become onerous to the MASA server large number of claims this might become onerous to the MASA server
which must maintain all the extra log entries. Ensuring the which must maintain all the extra log entries. Ensuring a Registrar
Registrar is representative of a valid customer domain even without is representative of a valid customer domain even without validating
validating ownership helps to mitigate this. ownership helps to mitigate this.
It is possible for an attacker to send an authorization request to It is possible for an attacker to send an authorization request to
the MASA service directly after the real Registrar obtains an the MASA service directly after the real Registrar obtains an
authorization log. If the attacker could also force the authorization log. If the attacker could also force the
bootstrapping protocol to reset there is a theoretical opportunity bootstrapping protocol to reset there is a theoretical opportunity
for the attacker to use the Audit Token to take control of the New for the attacker to use the Audit Voucher to take control of the
Entity but then proceed to enroll with the target domain. Possible Pledge but then proceed to enroll with the target domain. Possible
prevention mechanisms include: prevention mechanisms include:
o Per device rate limits on the MASA service ensure such timing o Per device rate limits on the MASA service ensure such timing
attacks are difficult. attacks are difficult.
o In the advent of an unexpectedly lost bootstrapping connection the o In the advent of an unexpectedly lost bootstrapping connection the
Registrar repeats the request for audit log information. Registrar repeats the request for audit log information.
To facilitate auditing the New Entity reports on audit token parsing To facilitate logging and administrative oversight the Pledge reports
status. In the case of a failure this information is informative to on Audit Voucher parsing status to the Registrar. In the case of a
the potentially malicious Registar but this is included because the failure this information is informative to a potentially malicious
operational benefits are concidered beneficial. Registar but this is RECOMMENDED anyway because of the operational
benefits of an informed administrator in cases where the failure is
indicative of a problem.
As indicated in EST [RFC7030] the connection is provisional and As indicated in EST [RFC7030] the connection is provisional and
untrusted until the server is successfully authorized. If the server untrusted until the server is successfully authorized. If the server
provides a redirect response the client MUST follow the redirect but provides a redirect response the client MUST follow the redirect but
the connection remains provisional. If the client uses a well known the connection remains provisional. If the client uses a well known
URI for contacting a well known Registrar the EST Implicit Trust URI for contacting a well known Registrar the EST Implicit Trust
Anchor database is used as is described in RFC6125 to authenticate Anchor database is used as is described in RFC6125 to authenticate
the well known URI. In this case the connection is not provisional the well known URI. In this case the connection is not provisional
and RFC6125 methods can be used for each subsequent redirection. and RFC6125 methods can be used for each subsequent redirection.
To facilitate truely limited clients EST RFC7030 section 3.3.2 To facilitate truely limited clients EST RFC7030 section 3.3.2
requirements that the client MUST support a client authentication requirements that the client MUST support a client authentication
model have been reduced in Section 6 to a statement that clients only model have been reduced in Section 6 to a statement that clients only
"SHOULD" support such a model. This reflects current (not great) "SHOULD" support such a model. This reflects current (not great)
practices but is NOT RECOMMENDED. practices but is NOT RECOMMENDED.
The MASA service could lock a claim and refuse to issue a new token The MASA service could lock a claim and refuse to issue a new voucher
or the MASA service could go offline (for example if a vendor went or the MASA service could go offline (for example if a vendor went
out of business). This functionality provides benefits such as theft out of business). This functionality provides benefits such as theft
resistance, but it also implies an operational risk to the Domain resistance, but it also implies an operational risk to the Domain
that Vendor behavior could limit future bootstrapping of the device that Vendor behavior could limit future bootstrapping of the device
by the Domain. This can be mitigated by Registrars that request by the Domain. This can be mitigated by Registrars that request
nonce-less authorization tokens. nonce-less Audit Vouchers.
7.1. Security concerns with discovery process
7.1.1. Discovery of Registrar by Proxy
As described in section Section 3.2, the RECOMMENDED mechanism is for
the proxy to discover the address of the registrar via GRASP
[I-D.ietf-anima-grasp]
GRASP is intended to run over a secured, and private Autonomic
Control Plan [I-D.ietf-anima-autonomic-control-plane]. This
discovery is between the already registered Registrar, and the
already registered Proxy. There are no GRASP security issues with
this part, as both entities will have already joined the secured ACP.
7.1.2. Discovery of Proxy by New Entity
[[EDNOTE: To be discussed]]
8. Acknowledgements 8. Acknowledgements
We would like to thank the various reviewers for their input, in We would like to thank the various reviewers for their input, in
particular Markus Stenberg, Brian Carpenter, Fuyu Eleven, Toerless particular Markus Stenberg, Brian Carpenter, Fuyu Eleven, Toerless
Eckert, Eliot Lear and Sergey Kasatkin. Eckert, Eliot Lear and Sergey Kasatkin.
9. References 9. References
9.1. Normative References 9.1. Normative References
skipping to change at page 44, line 34 skipping to change at page 45, line 7
December 2009, <http://standards.ieee.org/findstds/ December 2009, <http://standards.ieee.org/findstds/
standard/802.1AR-2009.html>. standard/802.1AR-2009.html>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC3542] Stevens, W., Thomas, M., Nordmark, E., and T. Jinmei, [RFC3542] Stevens, W., Thomas, M., Nordmark, E., and T. Jinmei,
"Advanced Sockets Application Program Interface (API) for "Advanced Sockets Application Program Interface (API) for
IPv6", RFC 3542, May 2003. IPv6", RFC 3542, DOI 10.17487/RFC3542, May 2003,
<http://www.rfc-editor.org/info/rfc3542>.
[RFC3927] Cheshire, S., Aboba, B., and E. Guttman, "Dynamic [RFC3927] Cheshire, S., Aboba, B., and E. Guttman, "Dynamic
Configuration of IPv4 Link-Local Addresses", RFC 3927, May Configuration of IPv4 Link-Local Addresses", RFC 3927,
2005. DOI 10.17487/RFC3927, May 2005,
<http://www.rfc-editor.org/info/rfc3927>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, September 2007. Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007,
<http://www.rfc-editor.org/info/rfc4862>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<http://www.rfc-editor.org/info/rfc5280>.
[RFC5386] Williams, N. and M. Richardson, "Better-Than-Nothing [RFC5386] Williams, N. and M. Richardson, "Better-Than-Nothing
Security: An Unauthenticated Mode of IPsec", RFC 5386, Security: An Unauthenticated Mode of IPsec", RFC 5386,
November 2008. DOI 10.17487/RFC5386, November 2008,
<http://www.rfc-editor.org/info/rfc5386>.
[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70, [RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
RFC 5652, DOI 10.17487/RFC5652, September 2009, RFC 5652, DOI 10.17487/RFC5652, September 2009,
<http://www.rfc-editor.org/info/rfc5652>. <http://www.rfc-editor.org/info/rfc5652>.
[RFC5660] Williams, N., "IPsec Channels: Connection Latching", [RFC5660] Williams, N., "IPsec Channels: Connection Latching",
RFC 5660, October 2009. RFC 5660, DOI 10.17487/RFC5660, October 2009,
<http://www.rfc-editor.org/info/rfc5660>.
[RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, [RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
DOI 10.17487/RFC6762, February 2013, DOI 10.17487/RFC6762, February 2013,
<http://www.rfc-editor.org/info/rfc6762>. <http://www.rfc-editor.org/info/rfc6762>.
[RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service [RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013, Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
<http://www.rfc-editor.org/info/rfc6763>. <http://www.rfc-editor.org/info/rfc6763>.
[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed., [RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
skipping to change at page 45, line 34 skipping to change at page 46, line 21
[I-D.behringer-homenet-trust-bootstrap] [I-D.behringer-homenet-trust-bootstrap]
Behringer, M., Pritikin, M., and S. Bjarnason, Behringer, M., Pritikin, M., and S. Bjarnason,
"Bootstrapping Trust on a Homenet", draft-behringer- "Bootstrapping Trust on a Homenet", draft-behringer-
homenet-trust-bootstrap-02 (work in progress), February homenet-trust-bootstrap-02 (work in progress), February
2014. 2014.
[I-D.ietf-ace-actors] [I-D.ietf-ace-actors]
Gerdes, S., Seitz, L., Selander, G., and C. Bormann, "An Gerdes, S., Seitz, L., Selander, G., and C. Bormann, "An
architecture for authorization in constrained architecture for authorization in constrained
environments", draft-ietf-ace-actors-03 (work in environments", draft-ietf-ace-actors-04 (work in
progress), March 2016. progress), September 2016.
[I-D.ietf-anima-autonomic-control-plane]
Behringer, M., Eckert, T., and S. Bjarnason, "An Autonomic
Control Plane", draft-ietf-anima-autonomic-control-
plane-03 (work in progress), July 2016.
[I-D.ietf-anima-grasp]
Bormann, C., Carpenter, B., and B. Liu, "A Generic
Autonomic Signaling Protocol (GRASP)", draft-ietf-anima-
grasp-08 (work in progress), October 2016.
[I-D.ietf-netconf-zerotouch] [I-D.ietf-netconf-zerotouch]
Watsen, K. and M. Abrahamsson, "Zero Touch Provisioning Watsen, K. and M. Abrahamsson, "Zero Touch Provisioning
for NETCONF or RESTCONF based Management", draft-ietf- for NETCONF or RESTCONF based Management", draft-ietf-
netconf-zerotouch-08 (work in progress), April 2016. netconf-zerotouch-09 (work in progress), July 2016.
[I-D.irtf-nmrg-autonomic-network-definitions]
Behringer, M., Pritikin, M., Bjarnason, S., Clemm, A.,
Carpenter, B., Jiang, S., and L. Ciavaglia, "Autonomic
Networking - Definitions and Design Goals", draft-irtf-
nmrg-autonomic-network-definitions-07 (work in progress),
March 2015.
[I-D.lear-mud-framework] [I-D.lear-mud-framework]
Lear, E., "Manufacturer Usage Description Framework", Lear, E., "Manufacturer Usage Description Framework",
draft-lear-mud-framework-00 (work in progress), January draft-lear-mud-framework-00 (work in progress), January
2016. 2016.
[I-D.richardson-anima-state-for-joinrouter] [I-D.richardson-anima-state-for-joinrouter]
Richardson, M., "Considerations for stateful vs stateless Richardson, M., "Considerations for stateful vs stateless
join router in ANIMA bootstrap", draft-richardson-anima- join router in ANIMA bootstrap", draft-richardson-anima-
state-for-joinrouter-00 (work in progress), January 2016. state-for-joinrouter-01 (work in progress), July 2016.
[imprinting] [imprinting]
Wikipedia, , "Wikipedia article: Imprinting", July 2015, Wikipedia, , "Wikipedia article: Imprinting", July 2015,
<https://en.wikipedia.org/wiki/Imprinting_(psychology)>. <https://en.wikipedia.org/wiki/Imprinting_(psychology)>.
[pledge] Dictionary.com, , "Dictionary.com Unabridged", July 2015, [pledge] Dictionary.com, , "Dictionary.com Unabridged", July 2015,
<http://dictionary.reference.com/browse/pledge>. <http://dictionary.reference.com/browse/pledge>.
[RFC7575] Behringer, M., Pritikin, M., Bjarnason, S., Clemm, A.,
Carpenter, B., Jiang, S., and L. Ciavaglia, "Autonomic
Networking: Definitions and Design Goals", RFC 7575,
DOI 10.17487/RFC7575, June 2015,
<http://www.rfc-editor.org/info/rfc7575>.
[Stajano99theresurrecting]
Stajano, F. and R. Anderson, "The resurrecting duckling:
security issues for ad-hoc wireless networks", 1999,
<https://www.cl.cam.ac.uk/~fms27/papers/1999-StajanoAnd-
duckling.pdf>.
Authors' Addresses Authors' Addresses
Max Pritikin Max Pritikin
Cisco Cisco
Email: pritikin@cisco.com Email: pritikin@cisco.com
Michael C. Richardson Michael C. Richardson
Sandelman Software Works Sandelman Software Works
470 Dawson Avenue
Ottawa, ON K1Z 5V7
CA
Email: mcr+ietf@sandelman.ca Email: mcr+ietf@sandelman.ca
URI: http://www.sandelman.ca/ URI: http://www.sandelman.ca/
Michael H. Behringer Michael H. Behringer
Cisco Cisco
Email: mbehring@cisco.com Email: mbehring@cisco.com
Steinthor Bjarnason Steinthor Bjarnason
Cisco Cisco
Email: sbjarnas@cisco.com Email: sbjarnas@cisco.com
Kent Watsen
Juniper Networks
Email: kwatsen@juniper.net
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