ANIMA WG M. Pritikin Internet-Draft Cisco Intended status: Informational M. Richardson Expires: April 20, 2016 SSW M. Behringer S. Bjarnason Cisco October 18, 2015 Bootstrapping Key Infrastructures draft-ietf-anima-bootstrapping-keyinfra-01 Abstract This document specifies automated bootstrapping of an key infrastructure using vendor installed IEEE 802.1AR manufacturing installed certificates, in combination with a vendor based service on the Internet. Before being authenticated, a new device has only link-local connectivity, and does not require a routable address. When a vendor provides an Internet based service, devices can be forced to join only specific domains but in limited/disconnected networks or legacy environments we describe a variety of options that allow bootstrapping to proceed. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on April 20, 2016. Copyright Notice Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved. Pritikin, et al. Expires April 20, 2016 [Page 1] Internet-Draft Bootstrapping Key Infrastructures October 2015 This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 2. Architectural Overview . . . . . . . . . . . . . . . . . . . 5 3. Functional Overview . . . . . . . . . . . . . . . . . . . . . 7 3.1. Behavior of a new entity . . . . . . . . . . . . . . . . 9 3.1.1. Discovery . . . . . . . . . . . . . . . . . . . . . . 11 3.1.2. Identity . . . . . . . . . . . . . . . . . . . . . . 12 3.1.3. Request Join . . . . . . . . . . . . . . . . . . . . 12 3.1.4. Imprint . . . . . . . . . . . . . . . . . . . . . . . 13 3.1.5. Enrollment . . . . . . . . . . . . . . . . . . . . . 14 3.1.6. Being Managed . . . . . . . . . . . . . . . . . . . . 14 3.2. Behavior of a proxy . . . . . . . . . . . . . . . . . . . 15 3.3. Behavior of the Registrar (Bootstrap Server) . . . . . . 15 3.3.1. Entity Authentication . . . . . . . . . . . . . . . . 16 3.3.2. Entity Authorization . . . . . . . . . . . . . . . . 16 3.3.3. Claiming the New Entity . . . . . . . . . . . . . . . 17 3.3.4. Log Verification . . . . . . . . . . . . . . . . . . 18 3.3.5. Forwarding Audit Token plus Configuration . . . . . . 18 3.4. Behavior of the MASA Service . . . . . . . . . . . . . . 19 3.4.1. Issue Authorization Token and Log the event . . . . . 19 3.4.2. Retrieve Audit Entries from Log . . . . . . . . . . . 19 3.5. Leveraging the new key infrastructure / next steps . . . 20 3.5.1. Network boundaries . . . . . . . . . . . . . . . . . 20 3.6. Interactions with Network Access Control . . . . . . . . 20 4. Domain Operator Activities . . . . . . . . . . . . . . . . . 20 4.1. Instantiating the Domain Certification Authority . . . . 21 4.2. Instantiating the Registrar . . . . . . . . . . . . . . . 21 4.3. Accepting New Entities . . . . . . . . . . . . . . . . . 21 4.4. Automatic Enrollment of Devices . . . . . . . . . . . . . 22 4.5. Secure Network Operations . . . . . . . . . . . . . . . . 22 5. Protocol Details . . . . . . . . . . . . . . . . . . . . . . 23 5.1. Request Audit Token . . . . . . . . . . . . . . . . . . . 25 5.2. Request Audit Token from MASA . . . . . . . . . . . . . . 26 5.3. Basic Configuration Information Package . . . . . . . . . 28 5.4. Request MASA authorization log . . . . . . . . . . . . . 28 6. Reduced security operational modes . . . . . . . . . . . . . 29 Pritikin, et al. Expires April 20, 2016 [Page 2] Internet-Draft Bootstrapping Key Infrastructures October 2015 6.1. New Entity security reductions . . . . . . . . . . . . . 29 6.2. Registrar security reductions . . . . . . . . . . . . . . 29 6.3. MASA security reductions . . . . . . . . . . . . . . . . 30 7. Security Considerations . . . . . . . . . . . . . . . . . . . 30 7.1. Trust Model . . . . . . . . . . . . . . . . . . . . . . . 32 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 32 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 32 9.1. Normative References . . . . . . . . . . . . . . . . . . 32 9.2. Informative References . . . . . . . . . . . . . . . . . 32 Appendix A. Editor notes . . . . . . . . . . . . . . . . . . . . 33 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 34 1. Introduction To literally "pull yourself up by the bootstraps" is an impossible action. Similarly the secure establishment of a key infrastructure without external help is also an impossibility. Today it is accepted that the initial connections between nodes are insecure, until key distribution is complete, or that domain-specific keying material is pre-provisioned on each new device in a costly and non-scalable manner. This document describes a zero-touch approach to bootstrapping an entity by securing the initial distribution of key material using third-party generic keying material, such as a manufacturer installed IEEE 802.1AR certificate [IDevID], and a corresponding third-party service on the Internet. The two sides of an association being bootstrapped authenticate each other and then determine appropriate authorization. This process is described as four distinct steps between the existing domain and the new entity being added: o New entity authentication: "Who is this? What is its identity?" o New entity authorization: "Is it mine? Do I want it? What are the chances it has been compromised?" o Domain authentication: "What is this domain's claimed identity?" o Domain authorization: "Should I join it?" A precise answer to these questions can not be obtained without leveraging an established key infrastructure(s). The domain's decisions are based on the new entity's authenticated identity, as established by verification of previously installed credentials such as a manufacturer installed IEEE 802.1AR certificate, and verified back-end information such as a configured list of purchased devices or communication with a trusted third-party. The new entity's Pritikin, et al. Expires April 20, 2016 [Page 3] Internet-Draft Bootstrapping Key Infrastructures October 2015 decisions are made according to verified communication with a trusted third-party or in a strictly auditable fasion. Optimal security is achieved with IEEE 802.1AR certificates on each new entity, accompanied by a third-party Internet based service for verification. Bootstrapping concepts run to completion with less requirements, but are then less secure. A domain can choose to accept lower levels of security when a trusted third-party is not available so that bootstrapping proceeds even at the risk of reduced security. Only the domain can make these decisions based on administrative input and known behavior of the new entity. The result of bootstrapping is that a domain specific key infrastructure is deployed. Since IEEE 802.1AR PKI certificates are used for identifying the new entity, and the public key of the domain identity is leveraged during communiciations with an Internet based service, which is itself authenticated using HTTPS, bootstrapping of a domain specific Public Key Infrastructure (PKI) is described. Sufficient agility to support bootstrapping alternative key infrastructures (such as symmetric key solutions) is considered although no such alternate key infrastructure is described. 1.1. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. The following terms are defined for clarity: 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 stored by the Domain CA. This is consistent with the RFC5280 Certification Authority subject key identifier of the Domain CA's self signed root certificate. (A string value bound to the Domain CA's self signed root certificate subject and issuer fields is often colloquially used as a 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 "factory default" configuration to a final destination. In zero- touch scenarios there is no staging or pre-configuration during drop-ship. imprint: the process where a device that wishes to join a network acquires it's domain specific identity. This term is taken from Konrad Lorenz's work in biology with new ducklings: during a Pritikin, et al. Expires April 20, 2016 [Page 4] Internet-Draft Bootstrapping Key Infrastructures October 2015 critical period, the duckling would assume that anything that looks like a mother duck is in fact their mother. [imprinting] pledge: the prospective device, which has the identity provided to at the factory. Neither the device nor the network knows if the 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 authority indicating that the bootstrapping event has been successfully logged. This has been referred to as an "authorization token" indicating that it authorizes bootstrapping to proceed. Ownership Voucher: A signed voucher from the vendor vouching that a specific domain "owns" the new entity. 2. Architectural Overview The logical elements of the bootstrapping framework are described in this section. Figure 1 provides a simplified overview of the components. Each component is logical and may be combined with other components as necessary. Pritikin, et al. Expires April 20, 2016 [Page 5] Internet-Draft Bootstrapping Key Infrastructures October 2015 . .+------------------------+ +--------------Drop Ship-------------->.| Vendor Service | | .+------------------------+ | .| M anufacturer| | | .| A uthorized |Ownership| | .| S igning |Tracker | | .| A uthority | | | .+--------------+---------+ | .............. ^ V | +-------+ ............................................|... | | . | . | | . +------------+ +-----------+ | . | | . | | | | | . | <---L2---> | | <-------+ . | | or | Proxy | | Registrar | . | <---L3---> <---L3--> | . | New | . | | | | . | Entity| . +------------+ +-----+-----+ . | | . | . | | . +-----------------+----------+ . | | . | Domain Certification | . | | . | Authority | . +-------+ . | Management and etc | . . +----------------------------+ . . . ................................................ "Domain" components 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 Pritikin, et al. Expires April 20, 2016 [Page 6] Internet-Draft Bootstrapping Key Infrastructures October 2015 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 trusted 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 be a MASA or Ownership Tracker for each vendor that supports devices following this document's specification, or an integrator could provide a MASA service for all devices. It is unlikely that an integrator could provide Ownership Tracking services for multiple vendors. This document describes a secure zero-touch approach to bootstrapping a key infrastructure; if certain devices in a network do not support this approach, they can still be bootstrapped manually. Although manual deployment is not scalable and is not a focus of this document the necessary mechanisms are called out in this document to ensure such edge conditions are covered by the architectural and protocol models. 3. Functional Overview Entities behave in an autonomic fashion. They discover each other and autonomically bootstrap into a key infrastructure deliminating the autonomic domain. See [I-D.irtf-nmrg-autonomic-network-definitions] for more information. Pritikin, et al. Expires April 20, 2016 [Page 7] Internet-Draft Bootstrapping Key Infrastructures October 2015 This section details the state machine and operational flow for each of the main three entities. The New Entity, the Domain (primarily the Registrar) and the MASA service. The overall flow is shown in Figure 2: +---------+ +----------+ +-----------+ | New | Proxy | | | Vendor | | Entity | not | Domain | | Service | | | shown | | | (Internet)| +---------+ +----------+ +-----------+ | | | |<-------discovery--------->| | |---IEEE 802.1AR identity-->| | | | | | [accept device?] | | | | | |---IEEE 802.1AR identity--->| | |---Domain ID--------------->| | | | | | [optional: does | | the device belong | | to the domain?] | | | | | [update audit log] | | | | |<---device audit log--------| | |<---audit token-------------| | |<-- ownership voucher-------| | | (optional) | | | | | [ still accept device?] | | | | |<----audit token-----------| | |<----ownership voucher-----| (optional) | |<----config information----| | | | | [audit token valid?] | | [or ownership voucher valid?] | | [apply config information] | | | | | |----domain enrollment----->| | |<----domain certificate----| | | | | Figure 2 Pritikin, et al. Expires April 20, 2016 [Page 8] Internet-Draft Bootstrapping Key Infrastructures October 2015 3.1. Behavior of a new entity A New Entity that has not yet been bootstrapped attempts to find a local domain and join it. States of a New Entity are as follows: +--------------+ | Start | | | +------+-------+ | +------v-------+ | Discover | +------------> | | +------+-------+ | | | +------v-------+ | | Identity | ^------------+ | | rejected +------+-------+ | | | +------v-------+ | | Request | | | Join | | +------+-------+ | | | +------v-------+ | | Imprint | Optional ^------------+ <--+Manual input | Bad Vendor +------+-------+ | response | | +------v-------+ | | Enroll | ^------------+ | | Enroll +------+-------+ | Failure | | +------v-------+ | | Being | ^------------+ Managed | Factory +--------------+ reset Figure 3 State descriptions are as follows: Pritikin, et al. Expires April 20, 2016 [Page 9] Internet-Draft Bootstrapping Key Infrastructures October 2015 1. Discover a communication channel to the "closest" Registrar by trying the following steps in this order: A. Search for a Proxy on the local link using a link local discovery protocol (no routable addresses are required for this approach). If multiple local proxies are discovered attempt communications with each before widening the search to other options. The proxy relays information to the registrar. If this fails: B. Obtain an IP address using existing methods, such as SLAAC or DHCPv6, and search for a local registrar using DNS service discovery. [[EDNOTE: ]]If this fails: C. Obtain an IP address (as above), and search for the domain registrar using a pre-defined Factory provided Internet based re-direct service. Various methods could be used, such as DNS or RESTful APIs. 2. Identify itself. This is done by presenting an IEEE 802.1AR credentials to the discovered Registrar (via a Proxy if necessary). Included is a generated nonce that is specific to this attempt. 3. Requests to Join the Discovered domain. The device indicates the Imprint methods it will accept and provides a nonce ensuring that any responses can be associated with this particular bootstrapping attempt. 4. Imprint on the Registrar. This requires verification of the MASA service generated Audit Token as provided by the contacted Registrar or the validation of the vendor provided ownership voucher. The Audit Token contains the DomainID information for this device and is signed by the MASA service. The device uses a pre-installed root certificate of the MASA service to validate the signature of the Audit Token or the Ownership Voucher. 5. Enroll by accepting the domain specific information from the Registrar, and by obtaining a domain certificate from the Registrar using a standard enrollment protocol, e.g. Enrolment over Secure Transport (EST) [RFC7030]. 6. The New Entity is now a member of, and can be managed by, the domain and will only repeat the discovery aspects of bootstrapping if it is returned to factory default settings. The following sections describe each of these steps in more detail. Pritikin, et al. Expires April 20, 2016 [Page 10] Internet-Draft Bootstrapping Key Infrastructures October 2015 3.1.1. Discovery Existing protocols provide the functionality for discovery of the Domain Bootstrap Server. The result of discovery might be communication with a proxy instead of a Domain Bootstrap Server. In such a case the proxy facilitates communication with the actual Domain Bootstrap Server in a manner that is transparent to the New Entity. To discover the Domain Bootstrap Server the New Entity performs the following actions in this order: 1. MUST: Obtains a local address using either IPv4 or IPv6 methods as described in [[EDNOTE: do we need a reference?]]. 2. MUST: Attempt to establish a TLS connection to the next hop neighbor at a well known AN port building on the [[EDNOTE: AN node discovery discussion, need a reference??]]. [Toerless to provide updated text] 3. MUST: unsecured-GRASP as a link local discovery method? [Toerless to provide updated text] 4. MAY: Performs DNS-based Service Discovery [RFC6763] over Multicast DNS [RFC6762] searching for the service "_bootstrapks._tcp.local." 5. MAY: Performs DNS-based Service Discovery [RFC6763] over normal DNS operations. In this case the domain is known so the service searched for is "_bootstrapks._tcp.example.com". 6. MAY: If no local bootstrapks service is located using the DNS- based Sevice Discovery methods the New Entity contacts a well known vendor provided bootstrapping server by perfoming a DNS lookup using a well known URI such as "bootstrapks.vendor- example.com". Once a domain bootstrapping server is discovered the New Entity communicates with the discovered server using the bootstrapping protocol defined in Section 5. The current DNS services returned during each query is maintained until bootstrapping is completed. If bootstrapping fails and the New Entity returns to the Discovery state it picks up where it left off and continues attempting bootstrapping. For example if the first Multicast DNS _bootstrapks._tcp.local response doens't work then the second and third responses are tried. If these fail the New Entity moves on to normal DNS-based Service Discovery. Pritikin, et al. Expires April 20, 2016 [Page 11] Internet-Draft Bootstrapping Key Infrastructures October 2015 Once all discovered services are attempted the device SHOULD return to Multicast DNS and keep trying. The New Entity may prioritize selection order as appropriate for the anticipated environment. [[EDNOTE: An appropriate backoff or rate limiting strategy should be defined here such that the device doesn't flood the local network with queries. If the device were to eventually give up -- or at least have too long between attempts -- a power cycle would restart the backoff mechanism.]] [[EDNOTE: it is unclear yet if discovery happens on a per interface basis or once per device. What is the requirement around joining multiple domains; is this a bootstrapping requirement or is this a broader autonomic requirement]] [[EDNOTE: b. carpenter: I seem to think we settled on joining one domain (which might be a sub-domain) and then doing some sort of cross-certification to get authenticated and authorized in another domain. If so, it isn't a bootstrap requirement.]] 3.1.2. Identity The New Entity identifies itself during the communication protocol handshake. If the client identity is rejected the New Entity repeats the Discovery process using the next proxy or discovery method available. The boostrapping protocol server is as of yet not validated. Thus this connection is provisional and all data recieved is untrusted until sufficiently validated even though it is over a (D)TLS connection. This is aligned with the existing provisional mode of EST [RFC7030] during s4.1.1 "Bootstrap Distribution of CA Certificates". All security associations established are between the new device and the Bootstrapping server regardless of proxy operations. 3.1.3. Request Join The New Entity POSTs a request to join the domain to the Bootstrapping server. This request contains a New Entity generated nonce and informs the Bootstrapping server which imprint methods the New Entity will accept. As indicated in EST [RFC7030] the bootstrapping server MAY redirect 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 communicating with the vendor's Registrar directly. In this case the New Entity has authenticated the Registrar using the local Implicit Pritikin, et al. Expires April 20, 2016 [Page 12] Internet-Draft Bootstrapping Key Infrastructures October 2015 Trust Anchor database and can therefore treat the redirect URI as a trusted URI which can also be validated using the Implicit Trust Anchor database. Since client authentication occurs during the TLS handshake the bootstrapping server has sufficient information to apply appropriate policy concerning which server to redirect to. The nonce ensures the New Entity can verify that responses are specific to this bootstrapping attempt. This minimizes the use of global time and provides a substantial benefit for devices without a valid clock. 3.1.4. Imprint The domain trust anchor is received by the New Entity during the boostrapping protocol methods in the form of either an Audit Token containing the domainID or an explicit ownership voucher. The goal of the imprint state is to securely obtain a copy of this trust anchor without involving human interaction. The enrollment protocol EST [RFC7030] details a set of non-autonomic bootstrapping methods such as: o using the Implicit Trust Anchor database (not an autonomic solution because the URL must be securely distributed), o engaging a human user to authorize the CA certificate using out- of-band data (not an autonomic solution because the human user is involved), o using a configured Explicit TA database (not an autonomic solution because the distribution of an explicit TA database is not autonomic), o and using a Certificate-Less TLS mutual authentication method (not an autonomic solution because the distribution of symmetric key material is not autonomic). This document describes additional autonomic methods: MASA audit token Audit tokens are obtained by the Registrar from the MASA service and presented to the New Entity for validation. These indicate to the New Entity that joining the domain has been logged by a trusted logging server. Ownership Voucher Ownership Vouchers are obtained by the Registrar from the MASA service and explicitly indicate the fully qualified domain name of the domain the new entity currently belongs to. Pritikin, et al. Expires April 20, 2016 [Page 13] Internet-Draft Bootstrapping Key Infrastructures October 2015 Since client authentication occurs during the TLS handshake the bootstrapping server has sufficient information to apply appropriate policy concerning which method to use. An arbitrary basic configuration information package that is signed by the domain can be delivered alongside the Audit Token or ownership validation. This information is signed by the domain private keys and is a one time delivery containing information such as which enrollment server to communicate with and which management system to communicate with. It is intended as a limited basic configuration for these purposes and is not intended to deliver entire final configuration to the device. If the autonomic methods fail the New Entity returns to discovery state and attempts bootstrapping with the next available discovered Registrar. 3.1.5. Enrollment As the final step of bootstrapping a Registrar helps to issue a domain specific credential to the New Entity. For simplicity in this document, a Registrar primarily facilitates issuing a credential by acting as an RFC5280 Registration Authority for the Domain Certification Authority. Enrollment proceeds as described in Enrollment over Secure Transport (EST) [RFC7030]. The New Entity contacts the Registrar using EST as indicated: 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 Owership 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. 3.1.6. Being Managed Functionality to provide generic "configuration" information is supported. The parsing of this data and any subsequent use of the data, for example communications with a Network Management System is out of scope but is expected to occur after bootstrapping enrollment is complete. This ensures that all communications with management systems which can divulge local security information (e.g. network Pritikin, et al. Expires April 20, 2016 [Page 14] Internet-Draft Bootstrapping Key Infrastructures October 2015 topology or raw key material) is secured using the local credentials issued during enrollment. See Section 3.5. 3.2. Behavior of a proxy The role of the Proxy is to facilitate communications. The Proxy forwards EST transport (TLS or DTLS) packets between the New Entity and the Registrar that has been configured on the Proxy. [[EDNOTE: To what extent do we need to explain how this occurs? It is sufficient to indicate the basic behavior or do we need to indicate here all the details? A rough implementation of an ipv4 proxy would be as follows: socat -v tcp4-listen:443,reuseaddr,fork tcp4:registrar.example.com:443 There have been suggestions that a stateless proxy implementation using a DTLS extension would be preferred. Is this a future optimization opportunity or a short term requirement?]] 3.3. Behavior of the Registrar (Bootstrap Server) Once a Registrar is established it listens for new entities and determines if they can join the domain. The registrar delivers any necessary authorization information to the new device and facilitates enrollment with the domain PKI. Registrar behavior is as follows: Pritikin, et al. Expires April 20, 2016 [Page 15] Internet-Draft Bootstrapping Key Infrastructures October 2015 Contacted by New Entity + | +-------v----------+ | Entity | fail? | Authentication +---------+ +-------+----------+ | | | +-------v----------+ | | Entity | fail? | | Authorization +---------> +-------+----------+ | | | +-------v----------+ | | Claiming the | fail? | | Entity +---------> +-------+----------+ | | | +-------v----------+ | | Log Verification | fail? | | +---------> +-------+----------+ | | | +-------v----------+ +----v-------+ | Forward | | | | Audit | | Reject | | token + config | | Device | | to the Entity | | | +------------------+ +------------+ Figure 4 3.3.1. Entity Authentication The applicable authentication methods detailed in EST [RFC7030] are: o the use of an IEEE 802.1AR IDevID credential, 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). 3.3.2. Entity Authorization In a fully automated network all devices must be securely identified and authorized to join the domain. Pritikin, et al. Expires April 20, 2016 [Page 16] Internet-Draft Bootstrapping Key Infrastructures October 2015 A Registrar accepts or declines a request to join the domain, based on the authenticated identity presented. Automated acceptance criteria include: o allow any device of a specific type (as determined by the IEEE 802.1AR device identity), o allow any device from a specific vendor (as determined by the IEEE 802.1AR identity), o allow a specific device from a vendor (as determined by the IEEE 802.1AR identity) Since all New Entities accept Audit Tokens the Registrar MUST use the vendor provided MASA service to verify that the device's history log does not include unexpected Registrars. If a device had previously registered with another domain, the Registrar of that domain would show 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 domain certificate through a certificate enrolment process. The result is a common trust anchor and device certificates for all autonomic devices in a domain (these certificates can subsequently be used to determine the boundaries of the homenet, to authenticate other domain nodes, and to autonomically enable services on the homenet). The authorization performed during this phase MAY be 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 Claiming an entity establishes an audit log at the MASA server and provides the Registrar with proof, in the form of a MASA authorization token, that the log entry has been inserted. As indicated in Section 3.1.4 a New Entity will only proceed with bootstrapping if a validated MASA authorization token has been recieved. The New Entity therefore enforces that bootstrapping only occurs if the claim has been logged. Registrar's obtain the MASA URI via static configuration or by extracting it from the IEEE 802.1AR credentail. [[EDNOTE: An Pritikin, et al. Expires April 20, 2016 [Page 17] Internet-Draft Bootstrapping Key Infrastructures October 2015 appropriate extension for indicating the MASA URI could be defined in this document]]. If ownership validation methods are being used the 'claiming' occured during out-of-band integration within the sales process and is out- of-scope. Instead the Registar simply requests an ownership validation token. During initial bootstrapping the New Entity provides a nonce specific to the particular bootstrapping attempt. The Registrar SHOULD include this nonce when claiming the New Entity from the MASA service. Claims from an unauthenticated Registrar are only serviced by the MASA resource if a nonce is provided. The Registrar can claim a New Entity that is not online by forming the request using the entities unique identifier and not including a nonce in the claim request. Audit Tokens obtained in this way do not have a lifetime and they provide a permanent method for the domain to claim the device. Evidence of such a claim is provided in the audit log entries available to any future Registrar. Such claims reduce the ability for future domains to secure bootstrapping and therefore the Registrar MUST be authenticated by the MASA service. [[EDNOTE: some of this paragraph content belongs in the section on MASA behavior]] 3.3.4. Log Verification The Registrar requests the log information for the new entity from the MASA service. The log is verified to confirm that the following is true to the satisfaction of the Registrar's configured policy: o Any nonceless entries in the log are associated with domainIDs recognized by the registrar. 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 are recognized by the registrar. If any of these criteria are unacceptable to the registrar the entity is rejected. The registar MAY be configured to ignore the history of the device but it is RECOMMENDED that this only be configured if hardware assisted NEA [RFC5209] is supported. 3.3.5. Forwarding Audit Token plus Configuration The Registrar forwards the received Audit Token to the New Entity. To simplify the message flows an initial configuration package can be Pritikin, et al. Expires April 20, 2016 [Page 18] Internet-Draft Bootstrapping Key Infrastructures October 2015 delivered at this time which is signed by a representative of the domain. [[EDNOTE: format TBD. The configuration package signature data must contain the full certificate path sufficient for the new entity to use the domainID information (as a trust anchor) to accept and validate the configuration)]] 3.4. Behavior of the MASA Service The MASA service is provided by the Factory provider on the global 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 Audit Token Distribution Point" extension). The MASA service provides the following functionalities to Registrars: 3.4.1. Issue Authorization Token and Log the event A Registrar POSTs a claim message optionally containing the bootstrap nonce to the MASA server. If a nonce is provided the MASA service responds to all requests. The MASA service verifies the Registrar is representative of the domain and generates a privacy protected log entry before responding with the Audit Token. If a nonce is not provided then the MASA service MUST authenticate the Registrar as a valid customer. This prevents denial of service attacks. The specific level of authentication provided by the customer is not defined here. An MASA Practice Statement (MPS) similar to the Certification Authority CPS, as defined in RFC5280, is provided by the Factory such that Registrar's can determine the level of trust they have in the Factory. 3.4.2. Retrieve Audit Entries from Log When determining if a New Entity should be accepted into a domain the Registrar retrieves a copy of the audit log from the MASA service. This contains a list of privacy protected domain identities that have previously claimed the device. Included in the list is an indication of the time the entry was made and if the nonce was included. Pritikin, et al. Expires April 20, 2016 [Page 19] Internet-Draft Bootstrapping Key Infrastructures October 2015 3.5. Leveraging the new key infrastructure / next steps As the devices have a common trust anchor, device identity can be securely established, making it possible to automatically deploy services across the domain in a secure manner. Examples of services: o Device management. o Routing authentication. o Service discovery. 3.5.1. Network boundaries When a device has joined the domain, it can validate the domain membership of other devices. This makes it possible to create trust boundaries where domain members have higher level of trusted than external devices. Using the autonomic User Interface, specific devices can be grouped into to sub domains and specific trust levels can be implemented between those. 3.6. Interactions with Network Access Control The assumption is that Network Access Control (NAC) completes using the New Entity 802.1AR credentials and results in the device having sufficient connetivity to discovery and communicate with the proxy. Any additional connectivity or quarantine behavior by the NAC infrastructure is out-of-scope. After the devices has completed bootstrapping the mechanism to trigger NAC to re-authenticate the device and provide updated network privileges is also out-of-scope. 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 previously required. Future optimizations can be achieved by integrating the bootstrapping protocol directly into an initial EAP exchange. 4. Domain Operator Activities This section describes how an operator interacts with a domain that supports the bootstrapping as described in this document. Pritikin, et al. Expires April 20, 2016 [Page 20] Internet-Draft Bootstrapping Key Infrastructures October 2015 4.1. Instantiating the Domain Certification Authority This is a one time step by the domain administrator. This is an "off the shelf" CA with the exception that it is designed to work as an integrated part of the security solution. This precludes the use of 3rd party certification authority services that do not provide support for delegation of certificate issuance decisions to a domain managed Registration Authority. 4.2. Instantiating the Registrar This is a one time step by the domain administrator. One or more 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 auto-select itself to take on this function, using a detection mechanism to resolve potential conflicts and setup communication with the Domain Certification Authority. Automated Registrar selection is outside scope for this document. 4.3. Accepting New Entities For each New Entity the Registrar is informed of the unique identifier (e.g. serial number) along with the manufacturer's identifying information (e.g. manufacturer root certificate). This can happen in different ways: 1. Default acceptance: In the simplest case, the new device asserts its unique identity to the registrar. The registrar accepts all devices without authorization checks. This mode does not provide security against intruders and is not recommended. 2. Per device acceptance: The new device asserts its unique identity to the registrar. A non-technical human validates the identity, for example by comparing the identity displayed by the registrar (for example using a smartphone app) with the identity shown on the packaging of the device. Acceptance may be triggered by a click on a smartphone app "accept this device", or by other forms of pairing. See also [I-D.behringer-homenet-trust-bootstrap] for how the approach could work in a homenet. 3. Whitelist acceptance: In larger networks, neither of the previous approaches is acceptable. Default acceptance is not secure, and a manual per device methods do not scale. Here, the registrar is provided a priori with a list of identifiers of devices that belong to the network. This list can be extracted from an inventory database, or sales records. If a device is detected Pritikin, et al. Expires April 20, 2016 [Page 21] Internet-Draft Bootstrapping Key Infrastructures October 2015 that is not on the list of known devices, it can still be manually accepted using the per device acceptance methods. 4. Automated Whitelist: an automated process that builds the necessary whitelists and inserts them into the larger network domain infrastructure is plausible. Once set up, no human intervention is required in this process. Defining the exact mechanisms for this is out of scope although the registrar authorization checks is identified as the logical integration point of any future work in this area. None of these approaches require the network to have permanent Internet connectivity. Even when the Internet based MASA service is used, it is possible to pre-fetch the required information from the MASA a priori, for example at time of purchase such that devices can enrol later. This supports use cases where the domain network may be entirely isolated during device deployment. Additional policy can be stored for future authorization decisions. For example an expected deployment time window or that a certain Proxy must be used. 4.4. Automatic Enrollment of Devices The approach outlined in this document provides a secure zero-touch method to enrol new devices without any pre-staged configuration. New devices communicate with already enrolled devices of the domain, which proxy between the new device and a Registrar. As a result of this completely automatic operation, all devices obtain a domain based certificate. 4.5. Secure Network Operations The certificate installed in the previous step can be used for all subsequent operations. For example, to determine the boundaries of the domain: If a neighbor has a certificate from the same trust anchor it can be assumed "inside" the same organization; if not, as outside. See also Section 3.5.1. The certificate can also be used to securely establish a connection between devices and central control functions. Also autonomic transactions can use the domain certificates to authenticate and/or encrypt direct interactions between devices. The usage of the domain certificates is outside scope for this document. Pritikin, et al. Expires April 20, 2016 [Page 22] Internet-Draft Bootstrapping Key Infrastructures October 2015 5. Protocol Details For simplicity the bootstrapping protocol is described as extensions to EST [RFC7030]. EST provides a bootstrapping mechanism for new entities that are configured with the URI of the EST server such that the Implicit TA database can be used to authenticate the EST server. Alternatively EST clients can "engage a human user to authorize the CA certificate using out-of-band data such as a CA certificate". EST does not provide a completely automated method of bootstrapping the PKI as both of these methods require some user input (either of the URI or authorizing the CA certificate). This section details additional EST functionality that support automated bootstrapping of the public key infrastructure. These additions provide for fully automated bootstrapping. These additions are to be optionally supported by the EST server within the same .well-known URI tree as the existing EST URIs. The "New Entity" is the EST client and the "Registrar" is the EST server. The extensions for the client are as follows: o The New Entity provisionally accept the EST server certificate during the TLS handshake as detailed in EST section 4.1.1 ("Bootstrap Distribution of CA Certificates"). o The Registrar requests and validates the Audit Token from the vendor authorized MASA service. o The New Entity requests and validates the Audit Token as described below. At this point the New Entity has sufficient information to validate domain credentials. o The New Entity calls the EST defined /cacerts method to obtain the current CA certificate. These are validated using the Audit Token. o The New Entity completes bootstrapping as detailed in EST section 4.1.1. These extensions could be implemented as an independent protocol from EST but since the overlap with basic enrollment is extensive, particularly with respect to client authorization, they are presented here as additions to EST. Pritikin, et al. Expires April 20, 2016 [Page 23] Internet-Draft Bootstrapping Key Infrastructures October 2015 In order to obtain a validated Audit Token and Audit Log the Registrar contacts the MASA service Service using REST calls: +-----------+ +----------+ +-----------+ +----------+ | New | | | | | | | | Entity | | Proxy | | Registrar | | Vendor | | | | | | | | | ++----------+ +--+-------+ +-----+-----+ +--------+-+ | | | | | | | | | (D)TLS hello | | | Establish +---------------> (D)TLS hello | | (D)TLS | |---------------> | connection | (forwarding) | | | Server Cert <---------------+ | <---------------+ | | | Client Cert | | | +-------------------------------> | | | | | HTTP REST | POST /requestaudittoken | | Data +--------------------nonce------> | | . | /requestaudittoken | . +----------------> | <----------------+ | | /requestauditlog | +----------------> | audit token or owner voucher <----------------+ <-------------------------------+ | | (optional config information) | | | . | | | . | | Figure 5 In some use cases the Registrar may need to contact the Vendor in advanced, for example when the target network is airgapped. The nonceless request format is provided for this and the resulting flow is slightly different. The security differences associated with not knowning the nonce are discussed below: Pritikin, et al. Expires April 20, 2016 [Page 24] Internet-Draft Bootstrapping Key Infrastructures October 2015 +-----------+ +----------+ +-----------+ +----------+ | New | | | | | | | | Entity | | Proxy | | Registrar | | Vendor | | | | | | | | | ++----------+ +--+-------+ +-----+-----+ +--------+-+ | | | | | | | | | | | /requestaudittoken | | (nonce +----------------> | | unknown) <----------------+ | | | /requestauditlog | | +----------------> | | <----------------+ | (D)TLS hello | | | Establish +---------------> (D)TLS hello | | (D)TLS | |---------------> | connection | (forwarding) | | | SerVer Cert <---------------+ | <---------------+ | | | Client Cert | | | +-------------------------------> | | | | | HTTP REST | POST /requestaudittoken | | Data +----------------------nonce----> (discard | | audit token or owner Voucher | nonce) | <-------------------------------+ | | (optional config information) | | | . | | | . | | Figure 6 5.1. Request Audit Token When the New Entity reaches the EST section 4.1.1 "Bootstrap Distribution of CA Certificates" state but wishes to proceed in a 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 "/requestaudittoken". The request format is JSON object containing a nonce. Request media type: application/auditnonce Request format: a JSON file with the following: Pritikin, et al. Expires April 20, 2016 [Page 25] Internet-Draft Bootstrapping Key Infrastructures October 2015 {"nonce":"<64bit nonce value>", "OwnershipValidation":boolean} [[EDNOTE: exact format TBD. There is an advantage to having the client sign the nonce (similar to a PKI Certification Signing Request) since this allows the MASA service to confirm the actual device identity. It is not clear that there is a security benefit from this since its the New Entity that verifies the nonce.]] The Registrar validates the client identity as described in EST [RFC7030] section 3.3.2. The registrar performs authorization as detailed in Section 3.3.2. If authorization is successful the Registrar obtains an Audit Token from the MASA service (see Section 5.2). The recieved MASA authorization token is returned to the New Entity. As indicated in EST [RFC7030] the bootstrapping server can redirect the client to an alternate server. If the New Entity authenticated the Registrar using the well known URI method then the New Entity MUST follow the redirect automatically and authenticate the new Registrar against the redirect URI provided. If the New Entity had not yet authenticated the Registrar because it was discovered and was not a known-to-be-valid URI then the new Registrar must be authenticated using one of the two autonomic methods described in this document. 5.2. Request Audit Token from MASA The Registrar requests the Audit Token from the MASA service using a REST interface. For simplicity this is defined as an optional EST message between the Registar and an EST server running on the MASA service although the Registrar is not required to make use of any other EST functionality when communicating with the MASA service. (The MASA service MUST properly reject any EST functionality requests it does not wish to service; a requirement that holds for any REST interface). This is done with an HTTP POST using the operation path value of "/requestaudittoken". The request format is a JSON object optionally containing the nonce value (as obtained from the bootstrap request) and the IEEE 802.1AR identity of the device as a serial number (the full certificate is not needed and no proof-of-possession information for the device identity is included). The New Entity's serial number is extracted from the subject name : Pritikin, et al. Expires April 20, 2016 [Page 26] Internet-Draft Bootstrapping Key Infrastructures October 2015 {"nonce":"<64bit nonce value>", "serialnumber", ""} Inclusion of the nonce is optional because the Registar might request an authorization token when the New Entity is not online, or when the target bootstrapping environment is not on the same network as the MASA server. The JSON message information is encapsulated in a PKCS7 signed data structure that is signed by the Registrar. The entire certificate chain, up to and including the Domain CA, MUST be included in the PKCS7. The MASA service checks the internal consistency of the PKCS7 but is unable to actually authenticate the domain identity information. The domain is not know to the MASA server in advance and a shared trust anchor is not implied. The MASA server verifies that the PKCS7 is signed by a Registrar (by checking for the cmc-idRA field in the Registrar certificate) certificate that was issued by a the root certificate included in the PKCS7. This is sufficient for the MASA service to ensure that the Registar is in fact an authorized Registar of the unknown domain. The domain ID (e.g. hash of the public key of the domain) is extracted from the root certificate and is used to generate the MASA authorization token and to update the audit log. [[EDNOTE: The authorization token response format needs to be defined here. It consists of the nonce, if supplied, the serialnumber and the trust anchor of the domain. For example: {"nonce":"<64bit nonce value>", "serialnumber", "","domainID":} ]] [[EDNOTE: This assumes the Registrar can extract the serial number successfullly from the cilent certificate. The RFC4108 hardwareModuleName is the best known location.]] [[EDNOTE: There is a strong similarity between this and the previous section. Both involve requesting the Audit Token from the upstream element. Because there are differing requirements on the data submitted and the signing of that data they are specified in distinct sections. The design team should have a meeting to discuss how to unify these sections or make the distinctions more clear]] Pritikin, et al. Expires April 20, 2016 [Page 27] Internet-Draft Bootstrapping Key Infrastructures October 2015 5.3. Basic Configuration Information Package When the MASA authorization token is returned to the New Entity an arbitrary information package can be signed and delivered along side it. This is signed by the Domain Registar. The New Entity first verifies the Audit Token and, if it is valid, then uses the domain's TA to validate the Information Package. [[EDNOTE: The package format to be specified here. Any signed format is viable and ideally one can simply be specified from netconf. The Registar knows the New Entity device type from the 802.1AR credential and so is able to determine the proper format for the configuration]] 5.4. Request MASA authorization log A registrar requests the MASA authorization log from the MASA service using this EST extension. This is done with an HTTP GET using the operation path value of "/requestMASAlog". The log data returned is a file consisting of all previous log entries. For example: "log":[ {"date":""}, "domainID":"", "nonce":""}, {"date":""}, "domainID":"", "nonce":""}, ] Distribution of a large log is less than ideal. This structure can be optimized as follows: only the most recent nonce'd log entry is required in the response. All nonce-less entries for the same domainID can be condensed into the single most recent nonceless entry. The Registrar uses this log information to make an informed decision regarding the continued bootstrapping of the New Entity. Pritikin, et al. Expires April 20, 2016 [Page 28] Internet-Draft Bootstrapping Key Infrastructures October 2015 [[EDNOTE: certificate transparency might offer an alternative log entry method]] 6. Reduced security operational modes A common requirement of bootstrapping is to support less secure operational modes for support specific use cases. The following sections detail specific ways that the New Entity, Registrar and MASA can be configured to run in a less secure mode for the indicated reasons. 6.1. New Entity security reductions Although New Entity can choose to run in less secure modes this is MUST NOT be the default state because it permanently degrades the security for all other uses cases. The device may have an operational mode where it skips Audit Token validation one time. For example if a physical button is depressed during the bootstrapping operation. This can be useful if the MASA service is unavailable. This behavior SHOULD be available via local configuration or physical presence methods to ensure new entities can always be deployed even when autonomic methods fail. It is RECOMMENDED that this only be available if hardware assisted NEA [RFC5209] is supported. 6.2. Registrar security reductions The Registrar can choose to accept devices using less secure methods. These methods are RECOMMENDED when low security models are needed as the security decisions are being made by the local administrator: 1. The registrar MAY choose to accept all devices, or all devices of a particular type, at the administrator's discretion. This could occur when informing the Registrar of unique identifiers of new entities might be operationally difficult. 2. The registrar MAY choose to accept devices that claim a unique identity without the benefit of authenticating that claimed identity. This could occur when the New Entity does not include an IEEE 802.1AR factory installed credential. 3. The registrar MAY request nonce-less Audit Tokens from the MASA service. These tokens can then be transmitted to the Registrar and stored until they are needed during bootstrapping operations. This is for use cases where target network is protected by an air Pritikin, et al. Expires April 20, 2016 [Page 29] Internet-Draft Bootstrapping Key Infrastructures October 2015 gap and therefore can not contact the MASA service during New Entity deployment. 4. The registrar MAY ignore unrecognized nonce-less Audit Log entries. This could occur when used equipment is purchased with a valid history being deployed in air gap networks that required permanent Audit Tokens. 6.3. MASA security reductions Lower security modes chosen by the MASA service effect all device deployments unless paired with strict device ownership validation, in which case these modes can be provided as additional features for specific customers. The MASA service can choose to run in less secure modes by: 1. Not enforcing that a Nonce is in the Audit Token. This results in distribution of Audit Tokens that never expire and effectly makes the Domain an always trusted entity to the New Entity during any subsequent bootstrapping attempts. That this occured is captured in the log information so that the Domain registrar can make appropriate security decisions when a new device joins the domain. This is useful to support use cases where Registrars might not be online during actual device deployment. Because this results in long lived Audit Tokens and do not require the proof that the device is online this is only accepted when the Registrar is authenticated by the MASA server and authorized to provide this functionality. The MASA server is RECOMMENDED to use this functionality only in concert with Ownership Validation tracking. 2. Not verifying ownership before responding with an Audit Token. This is expected to be a common operational model because doing so relieves the vendor providing MASA services from having to tracking ownership during shipping and supply chain and allows for a very low overhead MASA service. The Registrar uses the audit log information as a defense in depth strategy to ensure that this does not occur unexpectedly (for example when purchasing new equipment the Registrar would throw an error if any audit log information is reported). 7. Security Considerations In order to support a wide variety of use cases, devices can be claimed by a registrar without proving possession of the device in question. This would result in a nonceless, and thus always valid, claim. Or would result in an invalid nonce being associated with a claim. The MASA service is required to authenticate such Registrars Pritikin, et al. Expires April 20, 2016 [Page 30] Internet-Draft Bootstrapping Key Infrastructures October 2015 but no programmatic method is provided to ensure good behavior by the MASA service. Nonceless entries into the audit log therefore permanently reduce the value of a device because future Registrars, during future bootstrap attempts, would now have to be configured with policy to ignore previously (and potentially unknown) domains. Future registrars are recommended to take the audit history of a device into account when deciding to join such devices into their network. If the MASA server were to have allowed a significantly large number of claims this might become onerous to the MASA server which must maintain all the extra log entries. Ensuring the registar is representative of a valid customer domain even without validating ownership helps to mitigate this. It is possible for an attacker to send an authorization request to the MASA service directly after the real Registrar obtains an authorization log. If the attacker could also force the bootstrapping protocol to reset there is a theoretical opportunity for the attacker to use the Audit Token to take control of the New Entity but then proceed to enroll with the target domain. Possible prevention mechanisms include: o Per device rate limits on the MASA service ensure such timing attacks are difficult. o In the advent of an unexpectadly lost bootstrapping connection the Registrar repeats the request for audit log information. As indicated in EST [RFC7030] the connection is provisional and untrusted until the server is successfully authorized. If the server provides a redirect response the client MUST follow the redirect but the connection remains provisional. If the client uses a well known URI for contacting a well known Registrar the EST Implicit Trust Anchor database is used as is described in RFC6125 to authenticate the well known URI. In this case the connection is not provisional and RFC6125 methods can be used for each subsequent redirection. The MASA service could lock a claim and refuse to issue a new token or the MASA service could go offline (for example if a vendor went out of business). This functionality provides benefits such as theft resistance, but it also implies an operational risk to the Domain that Vendor behavior could limit future bootstrapping of the device by the Domain. This can be mitigated by Registrars that request nonce-less authorization tokens. Pritikin, et al. Expires April 20, 2016 [Page 31] Internet-Draft Bootstrapping Key Infrastructures October 2015 7.1. Trust Model [[EDNOTE: (need to describe that we need to trust the device h/w. To be completed.)]] 8. Acknowledgements We would like to thank the various reviewers for their input, in particular Markus Stenberg, Brian Carpenter, Fuyu Eleven. 9. References 9.1. Normative References [IDevID] IEEE Standard, , "IEEE 802.1AR Secure Device Identifier", December 2009, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ RFC2119, March 1997, . [RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed., "Enrollment over Secure Transport", RFC 7030, DOI 10.17487/RFC7030, October 2013, . 9.2. Informative References [I-D.behringer-homenet-trust-bootstrap] Behringer, M., Pritikin, M., and S. Bjarnason, "Bootstrapping Trust on a Homenet", draft-behringer- homenet-trust-bootstrap-02 (work in progress), February 2014. [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. [imprinting] Wikipedia, , "Wikipedia article: Imprinting", July 2015, . Pritikin, et al. Expires April 20, 2016 [Page 32] Internet-Draft Bootstrapping Key Infrastructures October 2015 [pledge] Dictionary.com, , "Dictionary.com Unabridged", July 2015, . Appendix A. Editor notes [[EDNOTE: This section is to capturing rough notes between editors and Anima Bootstrapping design team members. This entire section to be removed en masse before finalization]] Change Discussion: 03 updated figures added "ownership voucher" concepts added "request join" state to the new entity discussions broke discovery and identity into two sections added request join section expanded imprint autonomic methods as per design team discussions simplified proxy discussion as per design team discussions clarified 'entity authorization' clarified 'claiming the new entity' removed EAP-EST references expanded on protocol details as per ownership validation options slight additions to security considerations 02 Moved sections for readability, Updated introduction, simplified functional overview to avoid distractions from optional elements, addressed updated security considerations, fleshed out state machines. The following is a non-prioritized list of work items currently identified: o Continue to address gaps/opportunities highlighted by community work on bootstrappping. Refs: IETF92 "Survey of Security Bootstrapping", Aana Danping He, behcet Sarikaya. "NETCONF Zero Touch Update for ANIMA" https://www.ietf.org/proceedings/92/ anima.html and "Bootstrapping Key Infrastructures", Pritikin, Behringer, Bjarnason o IN PROGRESS: Intergrate "Ownership Voucher" as a valid optional format for the MASA response. So long as the issuance of this is logged and captured in the log response then the basic flow and threat model is substantially the same. o COMPLETE (moved to simple proxy): Attempt to re-use existing work as per the charter: Toerless notes: a) are existing [eap] options? or too complex? or doens't work? b) our own method (e.g. EAP- ANIMA c) if b then investigate using signaling protocol). o Pritikin, et al. Expires April 20, 2016 [Page 33] Internet-Draft Bootstrapping Key Infrastructures October 2015 Authors' Addresses Max Pritikin Cisco Email: pritikin@cisco.com Michael C. Richardson Sandelman Software Works 470 Dawson Avenue Ottawa, ON K1Z 5V7 CA Email: mcr+ietf@sandelman.ca URI: http://www.sandelman.ca/ Michael H. Behringer Cisco Email: mbehring@cisco.com Steinthor Bjarnason Cisco Email: sbjarnas@cisco.com Pritikin, et al. Expires April 20, 2016 [Page 34]