| anima Working Group | M. Richardson |
| Internet-Draft | Sandelman Software Works |
| Intended status: Standards Track | P. van der Stok |
| Expires: March 15, 2019 | vanderstok consultancy |
| P. Kampanakis | |
| Cisco Systems | |
| September 11, 2018 |
Constrained Voucher Artifacts for Bootstrapping Protocols
draft-ietf-anima-constrained-voucher-02
This document defines a strategy to securely assign a pledge to an owner, using an artifact signed, directly or indirectly, by the pledge's manufacturer. This artifact is known as a "voucher".
This document builds upon the work in [RFC8366], encoding the resulting artifact in CBOR. Use with two signature technologies are described.
Additionally, this document explains how constrained vouchers may be transported in the [I-D.ietf-ace-coap-est] protocol.
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 https://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 March 15, 2019.
Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://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.
Enrollment of new nodes into constrained networks with constrained nodes present unique challenges.
There are bandwidth and code space issues to contend. A solution such as [I-D.ietf-anima-bootstrapping-keyinfra] may be too large in terms of code space or bandwidth required.
This document defines a constrained version of [RFC8366]. Rather than serializing the YANG definition in JSON, it is serialized into CBOR ([RFC7049]).
This document follows a similar, but not identical structure as [RFC8366]. Some sections are left out entirely. Additional sections have been added concerning:
The CBOR definitions for this constrained voucher format are defined using the mechanism describe in [I-D.ietf-core-yang-cbor] using the SID mechanism explained in [I-D.ietf-core-sid]. As the tooling to convert YANG documents into an list of SID keys is still in its infancy, the table of SID values presented here should be considered normative rather than the output of the pyang tool.
Two methods of signing the resulting CBOR object are described in this document:
The following terms are defined in [RFC8366], and are used identically as in that document: artifact, imprint, domain, Join Registrar/Coordinator (JRC), Manufacturer Authorized Signing Authority (MASA), pledge, Trust of First Use (TOFU), and Voucher.
In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in BCP 14, RFC 2119 [RFC2119] and indicate requirement levels for compliant STuPiD implementations.
[RFC8366] provides for vouchers that assert proximity, that authenticate the registrar and that include different amounts of anti-replay protection.
This document does not make any extensions to the types of vouchers.
Time based vouchers are included in this definition, but given that constrained devices are extremely unlikely to know the correct time, their use is very unlikely. Most users of these constrained vouchers will be online and will use live nonces to provide anti-replay protection.
[RFC8366] defined only the voucher artifact, and not the Voucher Request artifact, which was defined in [I-D.ietf-anima-bootstrapping-keyinfra].
This document defines both a constrained voucher and a constrained voucher-request. They are presented in the order voucher-request, followed by voucher response as this is the time order that they occur.
This document defines both CMS-signed voucher requests and responses, and COSE signed voucher requests and responses. The use of CMS signatures implies the use of PKIX format certificates. The pinned-domain-cert present in such a voucher, is the certificate of the Registrar.
The use of COSE signatures permits the use of both PKIX format certificates, and also raw public keys (RPK). When RPKs are used, the voucher produced by the MASA pins the raw public key of the Registrar: the pinned-domain-subject-public-key-info in such a voucher, is the raw public key of the Registrar. This is described in the YANG definition for the constrained voucher.
This section describes the BRSKI extensions to EST-coaps [I-D.ietf-ace-coap-est] to transport the voucher between registrar, proxy and pledge over CoAP. The extensions are targeted to low-resource networks with small packets. Saving header space is important and the EST-coaps URI is shorter than the EST URI.
The presence and location of (path to) the management data are discovered by sending a GET request to "/.well-known/core" including a resource type (RT) parameter with the value "ace.est" [RFC6690]. Upon success, the return payload will contain the root resource of the EST resources. It is up to the implementation to choose its root resource; throughout this document the example root resource /est is used. The example below shows the discovery of the presence and location of voucher resources.
REQ: GET /.well-known/core?rt=ace.est RES: 2.05 Content </est>; rt="ace.est"
The EST-coaps server URIs differ from the EST URI by replacing the scheme https by coaps and by specifying shorter resource path names:
coaps://www.example.com/est/short-name
Figure 5 in section 3.2.2 of [RFC7030] enumerates the operations and corresponding paths which are supported by EST. Table 1 provides the mapping from the BRSKI extension URI path to the EST-coaps URI path.
| BRSKI | EST-coaps |
|---|---|
| /requestvoucher | /rv |
| /voucher-status | /vs |
| /enrollstatus | /es |
| /requestauditlog | /ra |
/requestvoucher and /enrollstatus are needed between pledge and Registrar.
When discovering the root path for the EST resources, the server MAY return the full resource paths and the used content types. This is useful when multiple content types are specified for EST-coaps server. For example, the following more complete response is possible.
REQ: GET /.well-known/core?rt=ace.est* RES: 2.05 Content </est>; rt="ace.est" </est/rv>; rt="ace.est/rv";ct=50 60 TBD2 TBD3 16 </est/vs>; rt="ace.est/vs";ct=50 60 </est/es>; rt="ace.est/es";ct=50 60 </est/ra>; rt="ace.est/ra";ct=TBD2 TBD3 16
The first line MUST be returned in response to the GET, The following four lines MAY be returned to show the supported Content-Formats. The return of the content-types allows the client to choose the most appropriate one from multiple content types.
ct=16 stands for the Content-Format "application/cose", and ct=TBD2 stands for Content-Format "application/voucher-cms+cbor, and ct=TBD3 stands for Content-Format "application/voucher-cose+cbor".
Content-Formats TBD2 and TBD3 are defined in this document. The return of the content-formats allows the client to choose the most appropriate one from multiple content formats.
The Content-Format ("application/json") 50 MAY be supported. Content-Formats ("application/cbor") 60, TBD2, TBD3, and 16 MUST be supported.
This section describes the abstract (tree) definition as explained in [I-D.ietf-netmod-yang-tree-diagrams] first. This provides a high-level view of the contents of each artifact.
Then the assigned SID values are presented. These have been assigned using the rules in [I-D.ietf-core-yang-cbor], with an allocation that was made via the http://comi.space service.
The following diagram is largely a duplicate of the contents of [RFC8366], with the addition of proximity-registrar-subject-public-key-info, proximity-registrar-cert, and prior-signed-voucher-request.
prior-signed-voucher-request is only used between the Registrar and the MASA. proximity-registrar-subject-public-key-info replaces proximity-registrar-cert for the extremely constrained cases.
module: ietf-constrained-voucher-request
grouping voucher-request-constrained-grouping
+-- voucher
+-- created-on?
| yang:date-and-time
+-- expires-on?
| yang:date-and-time
+-- assertion enumeration
+-- serial-number string
+-- idevid-issuer? binary
+-- pinned-domain-cert? binary
+-- domain-cert-revocation-checks? boolean
+-- nonce? binary
+-- last-renewal-date?
| yang:date-and-time
+-- proximity-registrar-subject-public-key-info? binary
+-- proximity-registrar-cert? binary
+-- prior-signed-voucher-request? binary
SID Assigned to
--------- --------------------------------------------------
1001154 data /ietf-constrained-voucher-request:voucher
1001155 data .../assertion
1001156 data .../created-on
1001157 data .../domain-cert-revocation-checks
1001158 data .../expires-on
1001159 data .../idevid-issuer
1001160 data .../last-renewal-date
1001161 data /ietf-constrained-voucher-request:voucher/nonce
1001162 data .../pinned-domain-cert
1001163 data .../prior-signed-voucher-request
1001164 data .../proximity-registrar-cert
1001165 data .../proximity-registrar-subject-public-key-info
1001166 data .../serial-number
In the constrained-voucher-request YANG module, the voucher is "augmented" within the "used" grouping statement such that one continuous set of SID values is generated for the constrained-voucher-request module name, all voucher attributes, and the constrained-voucher-request attribute. Two attributes of the voucher are "refined" to be optional.
<CODE BEGINS> file "ietf-constrained-voucher-request@2018-09-01.yang"
module ietf-constrained-voucher-request {
yang-version 1.1;
namespace
"urn:ietf:params:xml:ns:yang:ietf-constrained-voucher-request";
prefix "constrained";
import ietf-restconf {
prefix rc;
description
"This import statement is only present to access
the yang-data extension defined in RFC 8040.";
reference "RFC 8040: RESTCONF Protocol";
}
import ietf-voucher {
prefix "v";
}
organization
"IETF ANIMA Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/anima/>
WG List: <mailto:anima@ietf.org>
Author: Michael Richardson
<mailto:mcr+ietf@sandelman.ca>
Author: Peter van der Stok
<mailto: consultancy@vanderstok.org>
Author: Panos Kampanakis
<mailto: pkampana@cisco.com>";
description
"This module defines the format for a voucher request,
which is produced by a pledge to request a voucher.
The voucher-request is sent to the potential owner's
Registrar, which in turn sends the voucher request to
the manufacturer or delegate (MASA).
A voucher is then returned to the pledge, binding the
pledge to the owner. This is a constrained version of the
voucher-request present in
draft-ietf-anima-bootstrap-keyinfra.txt.
This version provides a very restricted subset appropriate
for very constrained devices.
In particular, it assumes that nonce-ful operation is
always required, that expiration dates are rather weak, as no
clocks can be assumed, and that the Registrar is identified
by a pinned Raw Public Key.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY',
and 'OPTIONAL' in the module text are to be interpreted as
described in RFC 2119.";
revision "2018-09-01" {
description
"Initial version";
reference
"RFC XXXX: Voucher Profile for Constrained Devices";
}
rc:yang-data voucher-request-constrained-artifact {
// YANG data template for a voucher.
uses voucher-request-constrained-grouping;
}
// Grouping defined for future usage
grouping voucher-request-constrained-grouping {
description
"Grouping to allow reuse/extensions in future work.";
uses v:voucher-artifact-grouping {
refine voucher/created-on {
mandatory false;
}
refine voucher/pinned-domain-cert {
mandatory false;
}
augment "voucher" {
description "Base the constrained voucher-request upon the
regular one";
leaf proximity-registrar-subject-public-key-info {
type binary;
description
"The proximity-registrar-subject-public-key-info replaces
the proximit-registrar-cert in constrained uses of
the voucher-request.
The proximity-registrar-subject-public-key-info is the
Raw Public Key of the Registrar. This field is encoded
as specified in RFC7250, section 3.
The ECDSA algorithm MUST be supported.
The EdDSA algorithm as specified in
draft-ietf-tls-rfc4492bis-17 SHOULD be supported.
Support for the DSA algorithm is not recommended.
Support for the RSA algorithm is a MAY.";
}
leaf proximity-registrar-cert {
type binary;
description
"An X.509 v3 certificate structure as specified by
RFC 5280,
Section 4 encoded using the ASN.1 distinguished encoding
rules (DER), as specified in ITU-T X.690.
The first certificate in the Registrar TLS server
certificate_list sequence (see [RFC5246]) presented by
the Registrar to the Pledge. This MUST be populated in a
Pledge's voucher request if the proximity assertion is
populated.";
}
leaf prior-signed-voucher-request {
type binary;
description
"If it is necessary to change a voucher, or re-sign and
forward a voucher that was previously provided along a
protocol path, then the previously signed voucher
SHOULD be included in this field.
For example, a pledge might sign a proximity voucher,
which an intermediate registrar then re-signs to
make its own proximity assertion. This is a simple
mechanism for a chain of trusted parties to change a
voucher, while maintaining the prior signature
information.
The pledge MUST ignore all prior voucher information
when accepting a voucher for imprinting. Other
parties MAY examine the prior signed voucher
information for the purposes of policy decisions.
For example this information could be useful to a
MASA to determine that both pledge and registrar
agree on proximity assertions. The MASA SHOULD
remove all prior-signed-voucher-request information when
signing a voucher for imprinting so as to minimize the
final voucher size.";
}
}
}
}
}
<CODE ENDS>
Below a CBOR serialization of the constrained-voucher-request is shown in diagnostic CBOR notation. The enum value of the assertion field is calculated to be zero by following the algorithm described in section 9.6.4.2 of [RFC7950].
{
1001101: {
+2 : "2016-10-07T19:31:42Z", / SID = 1001103, created-on /
+4 : "2016-10-21T19:31:42Z", / SID = 1001105, expires-on /
+1 : 0, / SID = 1001102, assertion /
/ "verified" /
+12: "JADA123456789", / SID = 1001113, serial-number /
+5 : h'01020D0F', / SID = 1001106, idevid-issuer /
+8 : h'01020D0F', / SID = 1001109, pinned-domain-cert/
+3 : true, / SID = 1001104, domain-cert
-revocation-checks /
+6 : "2017-10-07T19:31:42Z", / SID = 1001107, last-renewal-date /
+11: h'01020D0F' / SID = 1001112, proximity
-registrar-subject-public-key-info /
}
}
The voucher's primary purpose is to securely assign a pledge to an owner. The voucher informs the pledge which entity it should consider to be its owner.
This document defines a voucher that is a CBOR encoded instance of the YANG module defined in Section 5.3 that has been signed with CMS or with COSE.
The following diagram is largely a duplicate of the contents of [RFC8366], with only the addition of pinned-domain-subject-public-key-info.
module: ietf-constrained-voucher
grouping voucher-constrained-grouping
+-- voucher
+-- created-on? yang:date-and-time
+-- expires-on? yang:date-and-time
+-- assertion enumeration
+-- serial-number string
+-- idevid-issuer? binary
+-- pinned-domain-cert? binary
+-- domain-cert-revocation-checks? boolean
+-- nonce? binary
+-- last-renewal-date? yang:date-and-time
+-- pinned-domain-subject-public-key-info? binary
SID Assigned to
--------- --------------------------------------------------
1001104 data .../voucher
1001105 data .../assertion
1001106 data .../created-on
1001107 data .../domain-cert-revocation-checks
1001108 data .../expires-on
1001109 data .../idevid-issuer
1001110 data .../last-renewal-date
1001111 data .../nonce
1001112 data .../pinned-domain-cert
1001113 data .../pinned-domain-subject-public-key-info
1001114 data .../serial-number
In the constraine-voucher YANG module, the voucher is "augmented" within the "used" grouping statement such that one continuous set of SID values is generated for the constrained-voucher module name, all voucher attributes, and the constrained-voucher attribute. Two attributes of the voucher are "refined" to be optional.
<CODE BEGINS> file "ietf-constrained-voucher@2018-09-01.yang"
module ietf-constrained-voucher {
yang-version 1.1;
namespace
"urn:ietf:params:xml:ns:yang:ietf-constrained-voucher";
prefix "constrained";
import ietf-restconf {
prefix rc;
description
"This import statement is only present to access
the yang-data extension defined in RFC 8040.";
reference "RFC 8040: RESTCONF Protocol";
}
import ietf-voucher {
prefix "v";
}
organization
"IETF ANIMA Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/anima/>
WG List: <mailto:anima@ietf.org>
Author: Michael Richardson
<mailto:mcr+ietf@sandelman.ca>
Author: Peter van der Stok
<mailto: consultancy@vanderstok.org>
Author: Panos Kampanakis
<mailto: pkampana@cisco.com>";
description
"This module defines the format for a voucher, which is produced
by a pledge's manufacturer or delegate (MASA) to securely assign
one or more pledges to an 'owner', so that the pledges may
establis a secure connection to the owner's network
infrastructure.
This version provides a very restricted subset appropriate
for very constrained devices.
In particular, it assumes that nonce-ful operation is
always required, that expiration dates are rather weak, as no
clocks can be assumed, and that the Registrar is identified
by a pinned Raw Public Key.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY',
and 'OPTIONAL' in the module text are to be interpreted as
described in RFC 2119.";
revision "2018-09-01" {
description
"Initial version";
reference
"RFC XXXX: Voucher Profile for Constrained Devices";
}
rc:yang-data voucher-constrained-artifact {
// YANG data template for a voucher.
uses voucher-constrained-grouping;
}
// Grouping defined for future usage
grouping voucher-constrained-grouping {
description
"Grouping to allow reuse/extensions in future work.";
uses v:voucher-artifact-grouping {
refine voucher/created-on {
mandatory false;
}
refine voucher/pinned-domain-cert {
mandatory false;
}
augment "voucher" {
description "Base the constrained voucher
upon the regular one";
leaf pinned-domain-subject-public-key-info {
type binary;
description
"The pinned-domain-subject-public-key-info replaces the
pinned-domain-cert in constrained uses of
the voucher. The pinned-domain-subject-public-key-info
is the Raw Public Key of the Registrar.
This field is encoded as specified in RFC7250,
section 3.
The ECDSA algorithm MUST be supported.
The EdDSA algorithm as specified in
draft-ietf-tls-rfc4492bis-17 SHOULD be supported.
Support for the DSA algorithm is not recommended.
Support for the RSA algorithm is a MAY.";
}
}
}
}
}
<CODE ENDS>
Below a the CBOR serialization of the the constrained-voucher and constrained-voucher-request are shown in diagnostic CBOR notation. The enum value of the assertion field is calculated to be zero by following the algorithm described in section 9.6.4.2 of [RFC7950].
{
1001051: {
+2 : "2016-10-07T19:31:42Z", / SID = 1001053, created-on /
+4 : "2016-10-21T19:31:42Z", / SID = 1001055, expires-on /
+1 : 0, / SID = 1001052, assertion /
/ "verified" /
+10: "JADA123456789", / SID = 1001061, serial-number /
+5 : h'01020D0F', / SID = 1001056, idevid-issuer /
+8 : h'01020D0F', / SID = 1001059, pinned-domain-cert/
+3 : true, / SID = 1001054, domain-cert
-revocation-checks/
+6 : "2017-10-07T19:31:42Z", / SID = 1001057, last-renewal-date /
+9 : h'01020D0F' / SID = 1001060, pinned-domain
-subject-public-key-info /
}
}
The IETF evolution of PKCS#7 is CMS [RFC5652]. The CMS signed voucher is much like the equivalent voucher defined in [RFC8366].
A different eContentType of TBD1 is used to indicate that the contents are in a different format than in [RFC8366].
The ContentInfo structure contains a payload consisting of the CBOR encoded voucher. The [I-D.ietf-core-yang-cbor] use of delta encoding creates a canonical ordering for the keys on the wire. This canonical ordering is not important as there is no expectation that the content will be reproduced during the validation process.
Normally the recipient is the pledge and the signer is the MASA.
[I-D.ietf-anima-bootstrapping-keyinfra] supports both signed and unsigned voucher requests from the pledge to the JRC. In this specification, voucher-request artifact is not signed from the pledge to the registrar. From the JRC to the MASA, the voucher-request artifact MUST be signed by the domain owner key which is requesting ownership.
The considerations of [RFC5652] section 5.1, concerning validating CMS objects which are really PKCS7 objects (cmsVersion=1) applies.
The CMS structure SHOULD also contain all the certificates leading up to and including the signer's trust anchor certificate known to the recipient. The inclusion of the trust anchor is unusual in many applications, but without it third parties can not accurately audit the transaction.
The CMS structure MAY also contain revocation objects for any intermediate certificate authorities (CAs) between the voucher-issuer and the trust anchor known to the recipient. However, the use of CRLs and other validity mechanisms is discouraged, as the pledge is unlikely to be able to perform online checks, and is unlikely to have a trusted clock source. As described below, the use of short-lived vouchers and/or pledge provided nonce provides a freshness guarantee.
The COSE-Sign1 structure discussed in section 4.2 of [RFC8152]. The CBOR object that carries the body, the signature, and the information about the body and signature is called the COSE_Sign1 structure. It is used when only one signature is used on the body. The signature algorithm is ECSDA with three curves P-256, P-384, and P-512.
Support for EdDSA is encouraged.
Unlike with the CMS structure, the COSE-Sign1 structure does not provide a standard way for the signing keys to be included in the structure. This will not, in general, be a problem for the Pledge, as the key needed to verify the signature MUST be included at manufacturing time.
A problem arises for the Registrar: to verify the voucher, the Registrar must have access to the MASA's public key. This document does not specify how to transfer the relevant key.
The design considerations for the CBOR encoding of vouchers is much the same as for [RFC8366].
One key difference is that the names of the leaves in the YANG does not have a material effect on the size of the resulting CBOR, as the SID translation process assigns integers to the names.
TBD.
TBD.
TBD.
Additions to the sub-registry "CoAP Resource Type", within the "CoRE parameters" registry are specified below. These can be registered either in the Expert Review range (0-255) or IETF Review range (256-9999).
ace.rt.rv needs registration with IANA ace.rt.vs needs registration with IANA ace.rt.es needs registration with IANA ace.rt.ra needs registration with IANA
This document registers two URIs in the IETF XML registry [RFC3688]. Following the format in [RFC3688], the following registration is requested:
URI: urn:ietf:params:xml:ns:yang:ietf-constrained-voucher Registrant Contact: The ANIMA WG of the IETF. XML: N/A, the requested URI is an XML namespace. URI: urn:ietf:params:xml:ns:yang:ietf-constrained-voucher-request Registrant Contact: The ANIMA WG of the IETF. XML: N/A, the requested URI is an XML namespace.
This document registers two YANG modules in the YANG Module Names registry [RFC6020]. Following the format defined in [RFC6020], the the following registration is requested:
name: ietf-constrained-voucher
namespace: urn:ietf:params:xml:ns:yang:ietf-constrained-voucher
prefix: vch
reference: RFC XXXX
name: ietf-constrained-voucher-request
namespace: urn:ietf:params:xml:ns:yang:ietf-constrained
-voucher-request
prefix: vch
reference: RFC XXXX
This document registers an OID in the "SMI Security for S/MIME CMS Content Type" registry (1.2.840.113549.1.9.16.1), with the value:
Decimal Description References ------- -------------------------------------- ---------- TBD1 id-ct-animaCBORVoucher [ThisRFC]
EDNOTE: should a separate value be used for Voucher Requests?
The SID range 1001100 was allocated by comi.space to the IETF-CONSTRAINED-VOUCHER yang module.
The SID range 1001150 was allocated by comi.space to the IETF-CONSTRAINED-VOUCHER-REQUEST yang module.
EDNOTE: it is unclear if there is further IANA work required.
This section registers the 'application/voucher-cms+cbor' media type and the 'application/voucher-cose+cbor'in the "Media Types" registry. These media types are used to indicate that the content is a CBOR voucher either signed with a cms structure or a COSE_Sign1 structure [RFC8152].
Type name: application Subtype name: voucher-cms+cbor Required parameters: none Optional parameters: none Encoding considerations: CMS-signed CBOR vouchers are CBOR encoded. Security considerations: See Security Considerations, Section Interoperability considerations: The format is designed to be broadly interoperable. Published specification: THIS RFC. Applications that use this media type: ANIMA, 6tisch, and other zero-touch imprinting systems Additional information: Magic number(s): None File extension(s): .vch Macintosh file type code(s): none Person & email address to contact for further information: IETF ANIMA WG Intended usage: LIMITED Restrictions on usage: NONE Author: ANIMA WG Change controller: IETF Provisional registration? (standards tree only): NO
Type name: application
Subtype name: voucher-cose+cbor
Required parameters: none
Optional parameters: cose-type
Encoding considerations: COSE_Sign1 CBOR vouchers are COSE objects
signed with one signer.
Security considerations: See Security Considerations, Section
Interoperability considerations: The format is designed to be
broadly interoperable.
Published specification: THIS RFC.
Applications that use this media type: ANIMA, 6tisch, and other
zero-touch imprinting systems
Additional information:
Magic number(s): None
File extension(s): .vch
Macintosh file type code(s): none
Person & email address to contact for further information: IETF
ANIMA WG
Intended usage: LIMITED
Restrictions on usage: NONE
Author: ANIMA WG
Change controller: IETF
Provisional registration? (standards tree only): NO
Additions to the sub-registry "CoAP Content-Formats", within the "CoRE Parameters" registry are needed for two media types. These can be registered either in the Expert Review range (0-255) or IETF Review range (256-9999).
Media type mime type Encoding ID References ---------------------------- ----------- --------- ---- ---------- application/voucher-cms+cbor - - CBOR TBD2 [This RFC] application/voucher-cose+cbor "COSE-Sign1" CBOR TBD3 [This RFC]
We are very grateful to Jim Schaad for explaining COSE and CMS choices.
Michel Veillette did extensive work on pyang to extend it to support the SID allocation process, and this document was among the first users.
We are grateful for the suggestions done by Esko Dijk.
-02
Example of requestvoucher with unsigned appllication/cbor is added attributes of voucher "refined" to optional CBOR serialization of vouchers improved
-01
application/json is optional, application/cbor is compulsory Cms and cose mediatypes are introduced
| [I-D.ietf-ace-cbor-web-token] | Jones, M., Wahlstroem, E., Erdtman, S. and H. Tschofenig, "CBOR Web Token (CWT)", Internet-Draft draft-ietf-ace-cbor-web-token-15, March 2018. |
| [I-D.ietf-ace-coap-est] | Stok, P., Kampanakis, P., Kumar, S., Richardson, M., Furuhed, M. and S. Raza, "EST over secure CoAP (EST-coaps)", Internet-Draft draft-ietf-ace-coap-est-05, July 2018. |
| [I-D.ietf-anima-bootstrapping-keyinfra] | Pritikin, M., Richardson, M., Behringer, M., Bjarnason, S. and K. Watsen, "Bootstrapping Remote Secure Key Infrastructures (BRSKI)", Internet-Draft draft-ietf-anima-bootstrapping-keyinfra-16, June 2018. |
| [I-D.ietf-core-object-security] | Selander, G., Mattsson, J., Palombini, F. and L. Seitz, "Object Security for Constrained RESTful Environments (OSCORE)", Internet-Draft draft-ietf-core-object-security-14, July 2018. |
| [I-D.ietf-core-sid] | Veillette, M. and A. Pelov, "YANG Schema Item iDentifier (SID)", Internet-Draft draft-ietf-core-sid-04, June 2018. |
| [I-D.ietf-core-yang-cbor] | Veillette, M., Pelov, A., Somaraju, A., Turner, R. and A. Minaburo, "CBOR Encoding of Data Modeled with YANG", Internet-Draft draft-ietf-core-yang-cbor-06, February 2018. |
| [ieee802-1AR] | IEEE Standard, ., "IEEE 802.1AR Secure Device Identifier", 2009. |
| [RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997. |
| [RFC5652] | Housley, R., "Cryptographic Message Syntax (CMS)", STD 70, RFC 5652, DOI 10.17487/RFC5652, September 2009. |
| [RFC7049] | Bormann, C. and P. Hoffman, "Concise Binary Object Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049, October 2013. |
| [RFC7250] | Wouters, P., Tschofenig, H., Gilmore, J., Weiler, S. and T. Kivinen, "Using Raw Public Keys in Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)", RFC 7250, DOI 10.17487/RFC7250, June 2014. |
| [RFC7950] | Bjorklund, M., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016. |
| [RFC8152] | Schaad, J., "CBOR Object Signing and Encryption (COSE)", RFC 8152, DOI 10.17487/RFC8152, July 2017. |
| [RFC8366] | Watsen, K., Richardson, M., Pritikin, M. and T. Eckert, "A Voucher Artifact for Bootstrapping Protocols", RFC 8366, DOI 10.17487/RFC8366, May 2018. |
| [duckling] | Stajano, F. and R. Anderson, "The resurrecting duckling: security issues for ad-hoc wireless networks", 1999. |
| [I-D.ietf-netmod-yang-tree-diagrams] | Bjorklund, M. and L. Berger, "YANG Tree Diagrams", Internet-Draft draft-ietf-netmod-yang-tree-diagrams-06, February 2018. |
| [pledge] | Dictionary.com, ., "Dictionary.com Unabridged", 2015. |
| [RFC6690] | Shelby, Z., "Constrained RESTful Environments (CoRE) Link Format", RFC 6690, DOI 10.17487/RFC6690, August 2012. |
| [RFC7030] | Pritikin, M., Yee, P. and D. Harkins, "Enrollment over Secure Transport", RFC 7030, DOI 10.17487/RFC7030, October 2013. |
This section extends the examples from Appendix A of [I-D.ietf-ace-coap-est]. The CoAP headers are only worked out for the enrollstatus example.
A coaps enrollstatus message can be :
GET coaps://[192.0.2.1:8085]/est/es
The corresponding coap header fields are shown below.
Ver = 1
T = 0 (CON)
Code = 0x01 (0.01 is GET)
Options
Option1 (Uri-Host)
Option Delta = 0x3 (option nr = 3)
Option Length = 0x9
Option Value = 192.0.2.1
Option2 (Uri-Port)
Option Delta = 0x4 (option nr = 4+3=7)
Option Length = 0x4
Option Value = 8085
Option3 (Uri-Path)
Option Delta = 0x4 (option nr = 7+4= 11)
Option Length = 0x7
Option Value = /est/es
Payload = [Empty]
A 2.05 Content response with an unsigned JSON voucher (ct=50) will then be:
2.05 Content (Content-Format: application/json)
{payload}
With CoAP fields and payload:
Ver=1
T=2 (ACK)
Code = 0x45 (2.05 Content)
Options
Option1 (Content-Format)
Option Delta = 0xC (option nr 12)
Option Length = 0x2
Option Value = 0x32 (application/json)
Payload =
[EDNOTE: put here voucher payload ]
A coaps voucher_status message can be :
GET coaps://[2001:db8::2:1]:61616]/est/vs
A 2.05 Content response with a non signed CBOR voucher (ct=60) will then be:
2.05 Content (Content-Format: application/cbor)
Payload =
[EDNOTE: put here voucher payload ]
Two request-voucher request payloads are possible from pledge to Registrar, a signed one and an unsigned one, as explained in Section 5.2 of [I-D.ietf-anima-bootstrapping-keyinfra].
A coaps signed requestvoucher message from RA to MASA can be :
POST coaps://[2001:db8::2:1]:61616]/est/rv
A 2.04 Changed response returning CBOR voucher signed with a cms structure(ct=TBD2) will then be:
2.04 Changed (Content-Format: application/voucher-cms+cbor)
Payload =
[EDNOTE: put here encrypted voucher payload ]
A coaps unsigned requestvoucher message from pledge to Registrar can be :
POST coaps://[2001:db8::2:1]:61616]/est/rv
A 2.04 Changed response returning CBOR voucher (ct=60) will then be:
2.04 Changed (Content-Format: application/cbor)
Payload =
[EDNOTE: put here encrypted voucher payload ]
A coaps requestauditing message can be :
GET coaps://[2001:db8::2:1]:61616]/est/ra
A 2.05 Content response returning a COSE_Sign1 object (ct=TBD3) will then be:
2.05 Content (Content-Format: application/voucher-cose+cbor)
Payload =
[EDNOTE: put here COSE_Sign1 voucher payload ]