Concise Encoding of Signed Merkle Tree Proofs
draft-ietf-cose-merkle-tree-proofs-03
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| Authors | Orie Steele , Henk Birkholz , Antoine Delignat-Lavaud , Cedric Fournet | ||
| Last updated | 2024-01-30 (Latest revision 2023-12-11) | ||
| Replaces | draft-steele-cose-merkle-tree-proofs | ||
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draft-ietf-cose-merkle-tree-proofs-03
COSE O. Steele
Internet-Draft Transmute
Intended status: Standards Track H. Birkholz
Expires: 13 June 2024 Fraunhofer SIT
A. Delignat-Lavaud
C. Fournet
Microsoft
11 December 2023
Concise Encoding of Signed Merkle Tree Proofs
draft-ietf-cose-merkle-tree-proofs-03
Abstract
This specification describes verifiable data structures and
associated proof types for use with COSE. The extensibility of the
approach is demonstrated by providing CBOR encodings for RFC9162.
Discussion Venues
This note is to be removed before publishing as an RFC.
Discussion of this document takes place on the CBOR Object Signing
and Encryption Working Group mailing list (cose@ietf.org), which is
archived at https://mailarchive.ietf.org/arch/browse/cose/.
Source for this draft and an issue tracker can be found at
https://github.com/cose-wg/draft-ietf-cose-merkle-tree-proofs.
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 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 13 June 2024.
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Copyright Notice
Copyright (c) 2023 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 Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Notation . . . . . . . . . . . . . . . . . . 3
2. CBOR Tags . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Verifiable Data Structures in CBOR . . . . . . . . . . . . . 4
4.1. Structures . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. Parameters . . . . . . . . . . . . . . . . . . . . . . . 6
4.2.1. Registration Requirements . . . . . . . . . . . . . . 7
5. RFC9162_SHA256 . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Verifiable Data Structure . . . . . . . . . . . . . . . . 8
5.2. Inclusion Proof . . . . . . . . . . . . . . . . . . . . . 8
5.2.1. Inclusion Receipt . . . . . . . . . . . . . . . . . . 8
5.3. Consistency Proof . . . . . . . . . . . . . . . . . . . . 10
5.3.1. Consistency Receipt . . . . . . . . . . . . . . . . . 11
6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 12
6.1. Log Length . . . . . . . . . . . . . . . . . . . . . . . 13
6.2. Header Parameters . . . . . . . . . . . . . . . . . . . . 13
7. Security Considerations . . . . . . . . . . . . . . . . . . . 13
7.1. Choice of Signature Algorithms . . . . . . . . . . . . . 13
7.2. Validity Period . . . . . . . . . . . . . . . . . . . . . 13
7.3. Status Updates . . . . . . . . . . . . . . . . . . . . . 13
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
9.1. Additions to Existing Registries . . . . . . . . . . . . 14
9.1.1. New Entries to the COSE Header Parameters Registry . 14
9.1.2. COSE Verifiable Data Structures . . . . . . . . . . . 14
9.1.3. COSE Verifiable Data Structure Parameters . . . . . . 15
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
10.1. Normative References . . . . . . . . . . . . . . . . . . 15
10.2. Informative References . . . . . . . . . . . . . . . . . 17
Appendix A. Implementation Status . . . . . . . . . . . . . . . 17
A.1. Implementer . . . . . . . . . . . . . . . . . . . . . . . 18
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A.2. Implementation Name . . . . . . . . . . . . . . . . . . . 18
A.3. Implementation URL . . . . . . . . . . . . . . . . . . . 18
A.4. Maturity . . . . . . . . . . . . . . . . . . . . . . . . 18
A.5. Coverage and Version Compatibility . . . . . . . . . . . 18
A.6. License . . . . . . . . . . . . . . . . . . . . . . . . . 18
A.7. Implementation Dependencies . . . . . . . . . . . . . . . 19
A.8. Contact . . . . . . . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19
1. Introduction
Merkle trees are one of many verifiable data structures that enable
tamper evident secure information storage, through their ability to
protect the integrity of batches of documents or collections of
statements.
Merkle trees can be constructed from simple operations such as
concatenation and digest via a cryptographic hash function, however,
more advanced constructions enable proofs of different properties of
the underlying verifiable data structure.
Verifiable data structure proofs can be used to prove a document is
in a database (proof of inclusion), that a database is append only
(proof of consistency), that a smaller set of statements are
contained in a large set of statements (proof of disclosure, a
special case of proof of inclusion), or proof that certain data is
not yet present in a database (proofs of non inclusion).
Differences in the representation of verifiable data structures, and
verifiable data structure proof types, can increase the burden for
implementers, and create interoperability challenges for transparency
services.
This document describes how to convey verifiable data structures, and
associated proof types in COSE envelopes.
1.1. Requirements Notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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2. CBOR Tags
This section will be removed before the document is completed, its
purpose is to track the TBD code points references throughout the
draft.
-111 is TBD_1: A requested cose header parameter representing the
verifiable data structure used.
-222 is TBD_2: A requested cose header parameter representing the
verifiable data structure parameters map (proofs map)
The other codepoints are assigned from the registries established in
this draft, they are therefore not marked TBD.
3. Terminology
Verifiable Data Structure: A data structure which supports one or
more Proof Types.
Verifiable Data Structure Parameters: Parameters to a verifiable
data structure that are used to prove properties, such as
authentication, inclusion, consistency, and freshness. Parameters
can include multiple proofs of a given type, or multiple types of
proof (inclusion and consistency).
Proof Type: A verifiable process, that proves properties of a
Verifiable Data Structure.
Proof Value: An encoding of a Proof Type in CBOR.
4. Verifiable Data Structures in CBOR
This section describes representations of verifiable data structure
proofs in CBOR.
For example, construction of a merkle tree leaf, or an inclusion
proof from a leaf to a merkle root, might have several different
representations, depending on the verifiable data structure used.
Differences in representations are necessary to support efficient
verification, unique security or privacy properties, and for
compatibility with specific implementations.
In order to improve interoperability we define two extension points
for enabling verifiable data structures with COSE, and we provide
concrete examples for the structures and proofs defined in [RFC9162].
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4.1. Structures
Similar to COSE Key Types (https://www.iana.org/assignments/cose/
cose.xhtml#key-type), different verifiable data structures support
different algorithms. As EC2 keys (1: 2) support both digital
signature and key agreement algorithms, RFC9162_SHA256 (TBD_1 : 1)
supports both inclusion and consistency proofs.
This document establishes a registry of verifiable data structure
algorithms, with the following initial contents:
* Name: The name of the verifiable data structure
* Value: The identifier for the verifiable data structure
* Description: The identifier for the verifiable data structure
* Reference: Where the verifiable data structure is defined
+================+=======+===========================+===========+
| Name | Value | Description | Reference |
+================+=======+===========================+===========+
| N/A | 0 | N/A | N/A |
+----------------+-------+---------------------------+-----------+
| RFC9162_SHA256 | 1 | SHA256 Binary Merkle Tree | [RFC9162] |
+----------------+-------+---------------------------+-----------+
Table 1: COSE Verifiable Data Structures
When desigining new verifiable data structures, please request the
next available positive integer as your requested assignment, for
example:
+================+================+===============+===============+
| Name | Value | Description | Reference |
+================+================+===============+===============+
| N/A | 0 | N/A | N/A |
+----------------+----------------+---------------+---------------+
| RFC9162_SHA256 | 1 | SHA256 Binary | [RFC9162] |
| | | Merkle Tree | |
+----------------+----------------+---------------+---------------+
| Your name | TBD (requested | tbd | Your |
| | assignment 2) | | specification |
+----------------+----------------+---------------+---------------+
Table 2: How to register new structures
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4.2. Parameters
Similar to COSE Key Type Parameters
(https://www.iana.org/assignments/cose/cose.xhtml#key-type-
parameters), As EC2 keys (1: 2) keys require and give meaning to
specific parameters, such as -1 (crv), -2 (x), -3 (y), -4 (d),
RFC9162_SHA256 (TBD_1 : 1) supports both (-1) inclusion and (-2)
consistency proofs.
This document establishes a registry of verifiable data structure
algorithms, with the following initial contents:
+============+=============+=====+=======+=============+===========+
| Verifiable | Name |Label| CBOR | Description | Reference |
| Data | | | Type | | |
| Structure | | | | | |
+============+=============+=====+=======+=============+===========+
| 1 | inclusion |-1 | array | Proof of | Section |
| | proofs | | (of | inclusion | 5.2 |
| | | | bstr) | | |
+------------+-------------+-----+-------+-------------+-----------+
| 1 | consistency |-2 | array | Proof of | Section |
| | proofs | | (of | append only | 5.3 |
| | | | bstr) | property | |
+------------+-------------+-----+-------+-------------+-----------+
Table 3: COSE Verifiable Data Structure Parameters
Proof types are specific to their associated "verifiable data
structure", for example, different Merkle trees might support
different representations of "inclusion proof" or "consistency
proof".
Implementers should not expect interoperability accross "verifiable
data structures", but they should expect conceptually similar
properties across the different registered proof types.
For example, 2 different merkle tree based verifiable data structures
might both support proofs of inclusion.
Protocols requiring proof of inclusion ought to be able to preserve
their functionality, while switching from one verifiable data
structure to another, so long as both structures support the same
proof types.
Security analysis SHOULD be conducted prior to migrating to new
structures to ensure the new security and privacy assumptions are
acceptable for the use case.
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When designing new verifiable data structure parameters (or proof
types), please start with -1, and count down for each proof type
supported by your verifiable data structure:
+==========+===========+=====+=====+===========+==================+
|Verifiable|Name |Label|CBOR |Description|Reference |
|Data | | |Type | | |
|Structure | | | | | |
+==========+===========+=====+=====+===========+==================+
|1 |inclusion |-1 |array|Proof of |Section 5.2 |
| |proofs | |(of |inclusion | |
| | | |bstr)| | |
+----------+-----------+-----+-----+-----------+------------------+
|1 |consistency|-2 |array|Proof of |Section 5.3 |
| |proofs | |(of |append only| |
| | | |bstr)|property | |
+----------+-----------+-----+-----+-----------+------------------+
|TBD |new proof |-1 |tbd |tbd |Your_Specification|
|(requested|type | | | | |
|assignment| | | | | |
|2) | | | | | |
+----------+-----------+-----+-----+-----------+------------------+
|TBD |new proof |-2 |tbd |tbd |Your_Specification|
|(requested|type | | | | |
|assignment| | | | | |
|2) | | | | | |
+----------+-----------+-----+-----+-----------+------------------+
|TBD |new proof |-3 |tbd |tbd |Your_Specification|
|(requested|type | | | | |
|assignment| | | | | |
|2) | | | | | |
+----------+-----------+-----+-----+-----------+------------------+
Table 4: How to register new parameters
4.2.1. Registration Requirements
Each specification MUST define how to encode the verifiable data
structure and its parameters (also called proof types) in CBOR.
Each specification MUST define how to produce and consume the
supported proof types.
See Section 5 as an example.
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5. RFC9162_SHA256
This section defines how the data structures described in [RFC9162]
are mapped to the terminology defined in this document, using cbor
and cose.
5.1. Verifiable Data Structure
The integer identifier for this Verifiable Data Structure is 1. The
string identifier for this Verifiable Data Structure is
"RFC9162_SHA256".
See Table 1.
See [RFC9162], 2.1.1. Definition of the Merkle Tree, for a complete
description of this verifiable data structure.
5.2. Inclusion Proof
See [RFC9162], 2.1.3.1. Generating an Inclusion Proof, for a
complete description of this verifiable data structure proof type.
The cbor representation of an inclusion proof for RFC9162_SHA256 is:
inclusion-proof = [
tree-size: int
leaf-index: int
inclusion-path: [ + bstr ]
]
5.2.1. Inclusion Receipt
This specification sometimes refers to profiles of signed inclusion
proofs as "receipts".
In a signed inclusion proof, the previous merkle tree root, maps to
tree-size-1, and is a detached payload.
Profiles of proof signatures are encouraged to make additional
protected header parameters mandatory, to ensure that claims are
processed with their intended semantics.
One way to include this information in the COSE structure is use of
the typ (type) Header Parameter, see
[I-D.ietf-cose-typ-header-parameter] and the similar guidance
provided in [I-D.ietf-cose-cwt-claims-in-headers].
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The [I-D.ietf-scitt-architecture] describes one way in which signed
inclusion proofs can be leveraged to support supply chain
transparency.
The protected header for an RFC9162_SHA256 inclusion proof signature
is:
protected-header-map = {
&(alg: 1) => int
&(verifiable-data-structure: -111) => int
* cose-label => cose-value
}
* alg (label: 1): REQUIRED. Signature algorithm identifier. Value
type: int / tstr.
* verifiable-data-structure (label: -111): REQUIRED. verifiable data
structure algorithm identifier. Value type: int / tstr.
The unprotected header for an RFC9162_SHA256 inclusion proof
signature is:
inclusion-proofs = [ + bstr .cbor inclusion-proof ]
verifiable-proofs = {
&(inclusion-proof: -1) => inclusion-proofs
}
unprotected-header-map = {
&(verifiable-data-proof: -222) => verifiable-proofs
* cose-label => cose-value
}
* verifiable-data-proof (label: -222): REQUIRED.
* inclusion-proof (label: -1): REQUIRED.
The payload of an RFC9162_SHA256 inclusion proof signature is the
previous Merkle tree hash as defined in [RFC9162].
The payload MUST be detached.
Detaching the payload forces verifiers to recompute the root from the
inclusion proof signature, this protects against implementation
errors where the signature is verified but the root does not match
the inclusion proof.
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18( / COSE Sign 1 /
[
h'a4012604...6d706c65', / Protected /
{ / Unprotected /
-222: { / Proofs /
-1: [ / Inclusion proofs (1) /
h'83080783...32568964', / Inclusion proof 1 /
]
},
},
h'', / Detached payload /
h'2e34df43...8d74d55e' / Signature /
]
)
Figure 1: Example inclusion receipt
{ / Protected /
1: -7, / Algorithm /
4: h'4930714e...7163316b', / Key identifier /
-111: 1, / Verifiable Data Structure /
}
Figure 2: Example inclusion receipt decoded protected header
[ / Inclusion proof 1 /
8, / Tree size /
7, / Leaf index /
[ / Inclusion hashes (3) /
h'2a8d7dfc...15d10b22' / Intermediate hash 1 /
h'75f177fd...2e73a8ab' / Intermediate hash 2 /
h'0bdaaed3...32568964' / Intermediate hash 3 /
]
]
Figure 3: Example inclusion receipt decoded inclusion proof
5.3. Consistency Proof
See [RFC9162], 2.1.4.1. Generating a Consistency Proof, for a
complete description of this verifiable data structure proof type.
The cbor representation of a consistency proof for RFC9162_SHA256 is:
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consistency-proof = [
tree-size-1: int ; size of tree, at previous root
tree-size-2: int ; size of tree, at latest root
consistency-path: [ + bstr ] ; path from previous to latest root.
]
Editors note: tree-size-1, could be ommited, if an inclusion-proof is
always present, since the inclusion proof contains, tree-size-1.
5.3.1. Consistency Receipt
In a signed consistency proof, the latest merkle tree root, maps to
tree-size-2, and is an attached payload.
The protected header for an RFC9162_SHA256 consistency proof
signature is:
protected-header-map = {
&(alg: 1) => int
&(verifiable-data-structure: -111) => int
* cose-label => cose-value
}
* alg (label: 1): REQUIRED. Signature algorithm identifier. Value
type: int / tstr.
* verifiable-data-structure (label: TBD_1): REQUIRED. verifiable
data structure algorithm identifier. Value type: int / tstr.
The unprotected header for an RFC9162_SHA256 consistency proof
signature is:
consistency-proofs = [ + bstr ]
verifiable-proofs = {
&(consistency-proof: -2) => consistency-proofs
}
unprotected-header-map = {
&(verifiable-data-proof: -222) => verifiable-proofs
* cose-label => cose-value
}
* verifiable-data-proof (label: -222): REQUIRED.
* consistency-proof (label: -2): REQUIRED.
The payload of an RFC9162_SHA256 consistency proof signature is:
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The latest Merkle tree hash as defined in [RFC9162].
The payload MUST be attached.
18( / COSE Sign 1 /
[
h'a3012604...392b6601', / Protected /
{ / Unprotected /
-222: { / Proofs /
-2: [ / Consistency proofs (1) /
h'83040682...2e73a8ab', / Consistency proof 1 /
]
},
},
h'430b6fd7...f74c7fc4', / Payload /
h'd97befea...f30631cb' / Signature /
]
)
Figure 4: Example consistency receipt
{ / Protected /
1: -7, / Algorithm /
4: h'68747470...6d706c65', / Key identifier /
-111: 1, / Verifiable Data Structure /
}
Figure 5: Example consistency receipt decoded protected header
[ / Consistency proof 1 /
4, / Tree size 1 /
6, / Tree size 2 /
[ / Consistency hashes (2) /
h'0bdaaed3...32568964' / Intermediate hash 1 /
h'75f177fd...2e73a8ab' / Intermediate hash 2 /
]
]
Figure 6: Example consistency receipt decoded consistency proof
6. Privacy Considerations
See the privacy considerations section of:
* [RFC9162]
* [RFC9053]
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6.1. Log Length
Some structures and proofs leak the size of the log at the time of
inclusion. In the case that a log only stores certain kinds of
information, this can reveal details that could impact reputation.
For example, if a transparency log only stored breach notices, a
receipt for a breach notice would reveal the number of previous
breaches at the time the notice was made transparent.
6.2. Header Parameters
Additional header parameters can reveal information about the
transparency service or its log entries. A privacy analysis SHOULD
be performed for all mandatory fields in profiles based on this
specification.
7. Security Considerations
See the security considerations section of:
* [RFC9162]
* [RFC9053]
7.1. Choice of Signature Algorithms
A security analysis SHOULD be performed to ensure that the digitial
signature algorithm alg is the appropriate strength to secure
receipts.
7.2. Validity Period
In some cases, receipts SHOULD have strict validity periods, for
example, activation not too far in the future, or expiration, not too
far in the past. See the iat, nbf, and exp claims in [RFC8392], for
one way to accomplish this. The details of expressing validity
periods are out of scope for this document.
7.3. Status Updates
In some cases, receipts should be "revocable" or "suspendible", after
being issued, regardless of their validity period. The details of
expressing statuses are out of scope for this document.
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8. Acknowledgements
We would like to thank Maik Riechert, Jon Geater, Mike Jones, Mike
Prorock, Ilari Liusvaara, for their contributions (some of which
substantial) to this draft and to the initial set of implementations.
9. IANA Considerations
9.1. Additions to Existing Registries
9.1.1. New Entries to the COSE Header Parameters Registry
This document requests IANA to add new values to the 'COSE
Algorithms' and to the 'COSE Header Algorithm Parameters' registries
in the 'Standards Action With Expert Review category.
9.1.1.1. COSE Header Algorithm Parameters
* Name: verifiable-data-structure
* Label: TBD_1
* Value type: int / tstr
* Value registry: https://www.iana.org/assignments/cose/
cose.xhtml#header-parameters
* Description: Algorithm name for verifiable data structure, used to
produce verifiable data structure proofs.
* Name: verifiable-data-structure-parameters
* Label: TBD_2
* Value type: int / tstr
* Value registry: https://www.iana.org/assignments/cose/
cose.xhtml#header-parameters
* Description: Location for verifiable data structure proofs in COSE
Header Parameters.
9.1.2. COSE Verifiable Data Structures
IANA will be asked to establish a registry of verifiable data
structure identifiers, named "COSE Verifiable Data Structures" to be
administered under a Specification Required policy [RFC8126].
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Template:
* Name: The name of the verifiable data structure
* Value: The identifier for the verifiable data structure
* Description: The identifier for the verifiable data structure
* Reference: Where the verifiable data structure is defined
Initial contents: Provided in Table 1
9.1.3. COSE Verifiable Data Structure Parameters
IANA will be asked to establish a registry of verifiable data
structure parameters, named "COSE Verifiable Data Structure
Parameters" to be administered under a Specification Required policy
[RFC8126].
Template:
* Verifiable Data Structure: The identifier for the verifiable data
structure
* Name: The name of the proof type
* Label: The integer of the proof type
* CBOR Type: The cbor data type of the proof
* Description: The description of the proof type
* Reference: Where the proof type is defined
Initial contents: Provided in Table 3
10. References
10.1. Normative References
[BCP205] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", BCP 205,
RFC 7942, DOI 10.17487/RFC7942, July 2016,
<https://www.rfc-editor.org/rfc/rfc7942>.
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms
(SHA and SHA-based HMAC and HKDF)", RFC 6234,
DOI 10.17487/RFC6234, May 2011,
<https://www.rfc-editor.org/rfc/rfc6234>.
[RFC6962] Laurie, B., Langley, A., and E. Kasper, "Certificate
Transparency", RFC 6962, DOI 10.17487/RFC6962, June 2013,
<https://www.rfc-editor.org/rfc/rfc6962>.
[RFC6979] Pornin, T., "Deterministic Usage of the Digital Signature
Algorithm (DSA) and Elliptic Curve Digital Signature
Algorithm (ECDSA)", RFC 6979, DOI 10.17487/RFC6979, August
2013, <https://www.rfc-editor.org/rfc/rfc6979>.
[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
October 2013, <https://www.rfc-editor.org/rfc/rfc7049>.
[RFC8032] Josefsson, S. and I. Liusvaara, "Edwards-Curve Digital
Signature Algorithm (EdDSA)", RFC 8032,
DOI 10.17487/RFC8032, January 2017,
<https://www.rfc-editor.org/rfc/rfc8032>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/rfc/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8949] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", STD 94, RFC 8949,
DOI 10.17487/RFC8949, December 2020,
<https://www.rfc-editor.org/rfc/rfc8949>.
[RFC9053] Schaad, J., "CBOR Object Signing and Encryption (COSE):
Initial Algorithms", RFC 9053, DOI 10.17487/RFC9053,
August 2022, <https://www.rfc-editor.org/rfc/rfc9053>.
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[RFC9162] Laurie, B., Messeri, E., and R. Stradling, "Certificate
Transparency Version 2.0", RFC 9162, DOI 10.17487/RFC9162,
December 2021, <https://www.rfc-editor.org/rfc/rfc9162>.
10.2. Informative References
[I-D.ietf-cose-countersign]
Schaad, J., "CBOR Object Signing and Encryption (COSE):
Countersignatures", Work in Progress, Internet-Draft,
draft-ietf-cose-countersign-10, 20 September 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-cose-
countersign-10>.
[I-D.ietf-cose-cwt-claims-in-headers]
Looker, T. and M. B. Jones, "CBOR Web Token (CWT) Claims
in COSE Headers", Work in Progress, Internet-Draft, draft-
ietf-cose-cwt-claims-in-headers-10, 29 November 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-cose-
cwt-claims-in-headers-10>.
[I-D.ietf-cose-typ-header-parameter]
Jones, M. B. and O. Steele, "COSE "typ" (type) Header
Parameter", Work in Progress, Internet-Draft, draft-ietf-
cose-typ-header-parameter-02, 8 December 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-cose-
typ-header-parameter-02>.
[I-D.ietf-scitt-architecture]
Birkholz, H., Delignat-Lavaud, A., Fournet, C., Deshpande,
Y., and S. Lasker, "An Architecture for Trustworthy and
Transparent Digital Supply Chains", Work in Progress,
Internet-Draft, draft-ietf-scitt-architecture-04, 23
October 2023, <https://datatracker.ietf.org/doc/html/
draft-ietf-scitt-architecture-04>.
[RFC8392] Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig,
"CBOR Web Token (CWT)", RFC 8392, DOI 10.17487/RFC8392,
May 2018, <https://www.rfc-editor.org/rfc/rfc8392>.
Appendix A. Implementation Status
Note to RFC Editor: Please remove this section as well as references
to [BCP205] before AUTH48.
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in [BCP205].
The description of implementations in this section is intended to
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assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation
here does not imply endorsement by the IETF. Furthermore, no effort
has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
According to [BCP205], "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as
they see fit".
A.1. Implementer
An open-source implementation was initiated and is maintained by the
Transmute Industries Inc. - Transmute.
A.2. Implementation Name
An application demonstrating the concepts is available at
https://scitt.xyz (https://scitt.xyz).
A.3. Implementation URL
An open-source implementation is available at:
* https://github.com/transmute-industries/cose
A.4. Maturity
The code's level of maturity is considered to be "prototype".
A.5. Coverage and Version Compatibility
The current version ('main') implements the verifiable data structure
algorithm, inclusion proof and consistency proof concepts of this
draft.
A.6. License
The project and all corresponding code and data maintained on GitHub
are provided under the Apache License, version 2.
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A.7. Implementation Dependencies
The implementation builds on concepts described in SCITT
[I-D.ietf-scitt-architecture] (https://scitt.io/).
The implementation uses the Concise Binary Object Representation
[RFC7049] (https://cbor.io/).
The implementation uses the CBOR Object Signing and Encryption
[RFC9053], maintained at: - https://github.com/erdtman/cose-js
The implementation uses an implementation of [RFC9162], maintained
at:
* https://github.com/transmute-industries/rfc9162/tree/main/src/
CoMETRE
A.8. Contact
Orie Steele (orie@transmute.industries)
Authors' Addresses
Orie Steele
Transmute
United States
Email: orie@transmute.industries
Henk Birkholz
Fraunhofer SIT
Rheinstrasse 75
64295 Darmstadt
Germany
Email: henk.birkholz@sit.fraunhofer.de
Antoine Delignat-Lavaud
Microsoft
United Kingdom
Email: antdl@microsoft.com
Cedric Fournet
Microsoft
United Kingdom
Email: fournet@microsoft.com
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