Internet DRAFT - draft-jmiller-jose-json-proof-algorithms
draft-jmiller-jose-json-proof-algorithms
jose J. Miller
Internet-Draft Ping Identity
Intended status: Standards Track M. Jones
Expires: 11 September 2023 Microsoft
10 March 2023
JSON Proof Algorithms
draft-jmiller-jose-json-proof-algorithms-01
Abstract
The JSON Proof Algorithms (JPA) specification registers cryptographic
algorithms and identifiers to be used with the JSON Web Proof (JWP)
(https://www.ietf.org/archive/id/draft-jmiller-jose-json-web-proof-
01.html) and JSON Web Key (JWK) specifications. It defines several
IANA registries for these identifiers.
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
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This Internet-Draft will expire on 11 September 2023.
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
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provided without warranty as described in the Revised BSD License.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Background . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Algorithm Basics . . . . . . . . . . . . . . . . . . . . . . 4
5.1. Issue . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5.2. Confirm . . . . . . . . . . . . . . . . . . . . . . . . . 4
5.3. Present . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.4. Verify . . . . . . . . . . . . . . . . . . . . . . . . . 5
6. Algorithm Specifications . . . . . . . . . . . . . . . . . . 6
6.1. Single Use . . . . . . . . . . . . . . . . . . . . . . . 6
6.1.1. JWS Algorithm . . . . . . . . . . . . . . . . . . . . 6
6.1.2. Holder Setup . . . . . . . . . . . . . . . . . . . . 6
6.1.3. Issuer Setup . . . . . . . . . . . . . . . . . . . . 7
6.1.4. Using JWS . . . . . . . . . . . . . . . . . . . . . . 7
6.1.5. Issuer Protected Header . . . . . . . . . . . . . . . 7
6.1.6. Payloads . . . . . . . . . . . . . . . . . . . . . . 7
6.1.7. Presentation Protected Header . . . . . . . . . . . . 8
6.1.8. Presentation . . . . . . . . . . . . . . . . . . . . 8
6.1.9. Verification . . . . . . . . . . . . . . . . . . . . 9
6.1.10. JPA Registration . . . . . . . . . . . . . . . . . . 9
6.1.11. Example . . . . . . . . . . . . . . . . . . . . . . . 9
6.2. BBS . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.2.1. BLS Curve . . . . . . . . . . . . . . . . . . . . . . 10
6.2.2. Messages . . . . . . . . . . . . . . . . . . . . . . 10
6.2.3. Issuer Protected Header . . . . . . . . . . . . . . . 10
6.2.4. Payloads . . . . . . . . . . . . . . . . . . . . . . 10
6.2.5. Issuance . . . . . . . . . . . . . . . . . . . . . . 11
6.2.6. Presentation . . . . . . . . . . . . . . . . . . . . 11
6.2.7. Verification . . . . . . . . . . . . . . . . . . . . 11
6.2.8. JPA Registration . . . . . . . . . . . . . . . . . . 12
6.2.9. Example . . . . . . . . . . . . . . . . . . . . . . . 12
6.3. Message Authentication Code . . . . . . . . . . . . . . . 16
6.3.1. Holder Setup . . . . . . . . . . . . . . . . . . . . 17
6.3.2. Issuer Setup . . . . . . . . . . . . . . . . . . . . 17
6.3.3. Issuer Protected Header . . . . . . . . . . . . . . . 18
6.3.4. Payloads . . . . . . . . . . . . . . . . . . . . . . 18
6.3.5. Issuer Proof . . . . . . . . . . . . . . . . . . . . 18
6.3.6. Presentation Protected Header . . . . . . . . . . . . 19
6.3.7. Presentation . . . . . . . . . . . . . . . . . . . . 19
6.3.8. Verifier Setup . . . . . . . . . . . . . . . . . . . 19
6.3.9. JPA Registration . . . . . . . . . . . . . . . . . . 21
6.3.10. Example . . . . . . . . . . . . . . . . . . . . . . . 21
6.4. ZKSnark . . . . . . . . . . . . . . . . . . . . . . . . . 27
7. Security Considerations . . . . . . . . . . . . . . . . . . . 27
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27
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8.1. JWP Algorithms Registry . . . . . . . . . . . . . . . . . 27
9. Informative References . . . . . . . . . . . . . . . . . . . 27
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 28
Appendix B. Document History . . . . . . . . . . . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28
1. Introduction
The JSON Web Proof (JWP) (https://www.ietf.org/archive/id/draft-
jmiller-jose-json-web-proof-01.html) draft establishes a new secure
container format that supports selective disclosure and unlinkability
using Zero-Knowledge Proofs (ZKPs) or other cryptographic algorithms.
| Editor's Note: This draft is still early and incomplete, there
| will be significant changes to the algorithms as currently defined
| here. Please do not use any of these definitions or examples for
| anything except personal experimentation and learning.
| Contributions and feedback are welcome at https://github.com/json-
| web-proofs/json-web-proofs (https://github.com/json-web-proofs/
| json-web-proofs).
2. Conventions and Definitions
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.
The roles of "issuer", "holder", and "verifier" are used as defined
by the Verifiable Credentials Data Model v1.1
(https://www.w3.org/TR/2021/REC-vc-data-model-20211109/). The term
"presentation" is also used as defined by this source, but the term
"credential" is avoided in this specification in order to minimize
confusion with other definitions.
3. Terminology
The terms "JSON Web Signature (JWS)", "Base64url Encoding", "Header
Parameter", "JOSE Header", "JWS Payload", "JWS Signature", and "JWS
Protected Header" are defined by [RFC7515].
The terms "JSON Web Proof (JWP)", "JWP Payload", "JWP Proof", and
"JWP Protected Header" are defined by the JWP draft.
These terms are defined by this specification:
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Stable Key An asymmetric key-pair used by an issuer that is also
shared via an out-of-band mechanism to a verifier in order to
validate the signature.
Ephemeral Key An asymmetric key-pair that is generated for one-time
use by an issuer and never stored or used again outside of the
creation of a single JWP.
Presentation Key An asymmetric key-pair that is generated by a holder
and used to ensure that a presentation is not able to be replayed by
any other party.
4. Background
JWP defines a container binding together a protected header, one or
more payloads, and a cryptographic proof. It does not define any
details about the interactions between an application and the
cryptographic libraries that implement proof-supporting algorithms.
Due to the nature of ZKPs, this specification also documents the
subtle but important differences in proof algorithms versus those
defined by the JSON Web Algorithms [RFC7518]. These differences help
support more advanced capabilities such as blinded signatures and
predicate proofs.
5. Algorithm Basics
The four principal interactions that every proof algorithm MUST
support are [issue](#issue), [confirm](#confirm),
[present](#present), and [verify](#verify).
5.1. Issue
The JWP is first created as the output of a JPA's issue operation.
Every algorithm MUST support a JSON issuer protected header along
with one or more octet string payloads. The algorithm MAY support
using additional items provided by the holder for issuance such as
blinded payloads, keys for replay prevention, etc.
All algorithms MUST provide integrity protection for the issuer
header and all payloads and MUST specify all digest and/or hash2curve
methods used.
5.2. Confirm
Performed by the holder to validate the issued JWP is correctly
formed and protected.
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Each algorithm MAY support using additional input items options such
as those sent to the issuer for issuance. After confirmation, an
algorithm MAY return a modified JWP for serialized storage without
the local state (such as with blinded payloads now unblinded).
The algorithm MUST fully verify the issued proof value against the
issuer protected header and all payloads. If given a presented JWP
instead of an issued one the confirm process MUST return an error.
5.3. Present
Used to apply any selective disclosure choices and perform any
unlinkability transformations.
An algorithm MAY support additional input options from the requesting
party such as for predicate proofs and verifiable computation
requests.
Every algorithm MUST support the ability to hide any or all payloads.
It MUST always include the issuer protected header unmodified in the
presentation.
The algorithm MUST replace the issued proof value and generate a new
presented proof value. It also MUST include a new presentation
protected header that provides replay protection.
5.4. Verify
Performed by the verifier to verify the protected headers along with
any disclosed payloads and/or assertions about them from the proving
party, while also verifying they are the same payloads and ordering
as witnessed by the issuer.
The algorithm MUST verify the integrity of all disclosed payloads and
MUST also verify the integrity of both the issuer and presentation
protected headers.
If the presented proof contains any assertions about the hidden
payloads, the algorithm MUST also verify all of those assertions. It
MAY support additional options such as those sent to the holder to
generate the presentation.
If given an issued JWP for verification, the algorithm MUST return an
error.
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6. Algorithm Specifications
This section defines how to use specific algorithms for JWPs.
6.1. Single Use
| Editor's Note: This algorithm is going to be renamed and slightly
| refactored; the new name is still TBD.
The Single Use (SU) algorithm is based on composing multiple
traditional JWS values into a single JWP proof value. It enables a
very simple form of selective disclosure without requiring any
advanced cryptographic techniques.
It does not support unlinkability if the same JWP is presented
multiple times, therefore when privacy is required the holder will
need to interact with the issuer again to receive new single-use JWPs
(dynamically or in batches).
6.1.1. JWS Algorithm
The Single Use algorithm is based on using multiple JWS values, all
of which are generated with the same JSON Web Algorithm (JWA) for
signing. This JWA identifier is included as part of the Single Use
identifier for JWP.
The chosen JWA MUST be an asymmetric signing algorithm so that each
signature can be verified without sharing any private values between
the parties. This ensures that the verifier cannot brute force any
non-disclosed payloads based only on their disclosed individual
signatures.
6.1.2. Holder Setup
In order to support the protection of a presentation by a holder to a
verifier, the holder MUST use a Presentation Key during the issuance
and the presentation of every Single Use JWP. This Presentation Key
MUST be generated and used for only one JWP.
The issuer MUST verify that the holder has possession of this key.
The holder-issuer communication to exchange this information is out
of scope of this specification but can be easily accomplished by the
holder using this key to generate a JWS that signs a value the issuer
can verify as unique.
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6.1.3. Issuer Setup
To create a Single Use JWP the issuer first generates a unique
Ephemeral Key using the selected JWS algorithm. This key-pair will
be used to sign each of the payloads of a single JWP and then
discarded.
6.1.4. Using JWS
JSON Web Signatures are used to create all of the signature values
used by the SU algorithm. This allows an implementation to use an
existing JWS library directly for all necessary cryptographic
operations without requiring any additional primitives.
Each individual JWS uses a fixed protected header containing only the
minimum required alg value. Since this JWS protected header itself
is the same for every JWS, it SHOULD be a static value in the form of
{"alg":"***"} where *** is the JWA asymmetric signing key algorithm
identifier being used. This value is recreated by a verifier using
the correct JWA algorithm value included in the SU algorithm
identifier.
If an implementation uses an alternative JWS protected header than
this fixed value, a base64url encoded serialized form of the
alternate fixed header MUST be included using the jws_header claim in
the issuer protected header.
6.1.5. Issuer Protected Header
The JWK of the issuer's Ephemeral Key MUST be included in the issuer
protected header with the property name of proof_jwk and contain only
the REQUIRED values to represent the public key.
The holder's Presentation Key JWK MUST be included in issuer
protected header using the presentation_jwk claim.
The final issuer protected header is then used directly as the body
of a JWS and signed using the issuer's Stable Key. The resulting JWS
signature value unencoded octet string is the first value in the JWP
proof.
6.1.6. Payloads
Each JWP payload is processed in order and signed as a JWS body using
the issuer's Ephemeral Key. The resulting JWS signature value
unencoded octet string is appended to the JWP proof.
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The proof value as an octet string will have a total length that is
the sum of the fixed length of the issuer protected header signature
plus the fixed length of each of the payload Ephemeral Key
signatures. For example, the signature for the ES256 algorithm is 64
octets and for a JWP with five payloads the total proof value length
would be 64 * (1 + 5) = 384 octets).
6.1.7. Presentation Protected Header
In order to generate a new presentation, the holder first creates a
presentation protected header that is specific to the verifier being
presented to. This header MUST contain a claim that both the holder
and verifier trust as being unique and non-replayable.
This specification registers a nonce claim for the presentation
protected header that contains a string value either generated by the
verifier or derived from values provided by the verifier. When
present, the verifier MUST ensure the nonce value matches during
verification.
The presentation protected header MAY contain other claims that are
either provided by the verifier or by the holder. These presentation
claims SHOULD NOT contain values that are common across multiple
presentations and SHOULD be unique to a single presentation and
verifier.
6.1.8. Presentation
| Editor's Note: The current definition here is incomplete, the
| holder's signature needs to also incorporate the presented proof.
The holder derives a new proof value when presenting it to a
verifier. The presented proof value will always contain the issuer's
Stable Key signature for the issuer protected header as the first
element.
The second element of the presented proof value is always the
holder's Presentation Key signature of the presentation protected
header, constructed identically to the issuer protected header by
using the serialized JSON value octet string as the JWS body.
Signing only the presentation header with the Presentation Key is
sufficient to protect the entire presentation since that key is
private to the holder and only the contents of the presentation
header are used for replay prevention.
The two header signatures are then followed by only the issuer's
Ephemeral Key signatures for each payload that is disclosed. The
order of the payload signatures is preserved and MUST be in the same
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order as the included disclosed payloads in the presented JWP. Non-
disclosed payloads will NOT have a signature value included. For
example, if the second and fifth payloads are hidden then the
holder's derived proof value would be of the length 64 * (1 + 1 + the
1st, 2nd, and 4th payload signatures) = 320 octets.
Since the individual signatures in the proof value are unique and
remain unchanged across multiple presentations, a Single Use JWP
SHOULD only be presented a single time to each verifier in order for
the holder to remain unlinkable across multiple presentations.
6.1.9. Verification
The verifier MUST verify the issuer protected header against the
first matching JWS signature part in the proof value using the
issuer's Stable Key. It MUST also verify the presentation protected
header against the second JWS signature part in the proof value using
the holder's Presentation Key as provided in the presentation_jwk
claim in the issuer protected header.
With the headers verified, the issuer's Ephemeral Key as given in the
issuer protected header proof_jwk claim can then be used to verify
each of the disclosed payload signatures.
6.1.10. JPA Registration
Proposed JWP alg value is of the format "SU-" appended with the
relevant JWS alg value for the chosen public and ephemeral key-pair
algorithm, for example "SU-ES256".
6.1.11. Example
See the example in the appendix of the JSON Web Proof draft.
6.2. BBS
The BBS Signature Scheme under active standards development as a work
item (https://github.com/decentralized-identity/bbs-signature) within
the DIF Applied Cryptography Working Group
(https://identity.foundation/working-groups/crypto.html). Prior to
this effort, a V1 implementation of BBS
(https://github.com/mattrglobal/bbs-signatures) has been released and
maintained by a community of individuals with notable adoption in
multiple early stage decentralized identity projects.
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This JSON Proof Algorithm definition for BBS is based on the already
released implementation and relies on the provided software API. A
future definition with a different alg value will be created to
succeed this version as the BBS standardization effort progresses.
This algorithm supports both selective disclosure and unlinkability,
enabling the holder to generate multiple presentations from one
issued JWP without any verifier being able to correlate those
presentations together.
6.2.1. BLS Curve
The pairing friendly elliptic curve used for the BBS software
implementation is part of the BLS family with an embedding degree of
12 over a 381-bit prime field. For this JPA, only the group G2 is
used.
In the implementation the method used to generate the key pairs is
generateBls12381G2KeyPair().
6.2.2. Messages
BBS is a multi-message scheme and operates on an array of individual
messages for signing and proof generation. Each message is a single
binary octet string. The BBS implementation uses a hash-to-curve
method to map each message to a point.
6.2.3. Issuer Protected Header
The UTF-8 octet string of the issuer protected header is the first
message in the input array at index 0.
6.2.4. Payloads
The octet strings of each payload are placed into the BBS message
array following the issuer protected header message. For example,
the first payload is at index 1 of the array and the last payload is
always the last message in the array.
In future versions of this algorithm, there will be additional
methods defined for transforming a payload into a point such that
additional Zero-Knowledge Proof types can be supported by the holder
such as range and membership predicates.
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6.2.5. Issuance
The issuer's BLS12-381 G2 Stable Key is used to sign the completed
message array input containing the octet strings of the issuer
protected header and every payload. The result is a signature octet
string that is used as the initial JWP proof value.
In the implementation, the method used to perform the signing is
blsSign({keyPair, [header, payload1, payload2, ...]}) and returns a
binary signature value.
6.2.6. Presentation
The holder must decode the issuer protected header and payload values
in order to generate the identical message array that the issuer
used.
To generate a presented JWP for a verifier, the holder must use a
cryptographic nonce that is provided by that verifier as input. This
nonce MUST be a 32-byte octet string that the verifier generated by a
secure RNG. How this nonce value is communicated to the holder is
out of scope of this presentation. The nonce claim in the
presentation protected header is used to store the verifier's given
nonce value.
The holder also applies selective disclosure preferences by creating
an array of indices of which messages in the input array are to be
revealed to the verifier. The revealed indices MUST include the
value 0 so that the issuer protected header message is always
revealed to the verifier.
The result of creating a proof is an octet string that is used as the
presented JWP proof value.
In the implementation, the method used to generate the proof is
blsCreateProof({signedProof, publicKey, [issuer_header, payload1,
payload2, ...], presentation_header, [0, 2, ...]).
6.2.7. Verification
The verifier decodes the JWP issuer protected header and payload
values into a messages array, skipping any non-revealed payloads.
The current BBS implementation embeds the revealed indices into the
output proof value, so the verification messages array only needs to
include the disclosed messages.
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In the implementation, the method used to verify the proof is
blsVerifyProof({verifyProof, publicKey, [issuer_header, payload2,
...], presentation_header).
6.2.8. JPA Registration
Proposed JWP alg value for BBS based on the software implementation
is "BBS-X".
6.2.9. Example
The following example uses the given BLS12-384 key-pair:
Public:
[179, 209, 122, 60, 230, 37, 188, 86, 19, 19, 4, 36, 240, 230, 79,
178, 230, 147, 9, 60, 239, 41, 233, 167, 190, 252, 154, 35, 39, 201,
238, 73, 77, 228, 20, 47, 109, 174, 15, 168, 187, 145, 126, 85, 83,
151, 48, 30, 13, 237, 92, 179, 124, 181, 211, 204, 187, 222, 229,
234, 182, 94, 60, 157, 19, 148, 162, 48, 185, 134, 177, 168, 68,
115, 167, 48, 92, 181, 168, 53, 52, 246, 201, 112, 103, 23, 159,
138, 225, 13, 165, 171, 251, 112, 163, 96]
Figure 1: bbs-issuer-public-octets
Private:
[72, 125, 227, 97, 150, 148, 186, 145, 110, 46, 135, 232, 104, 204,
128, 242, 73, 151, 72, 162, 0, 54, 139, 146, 221, 137, 34, 74, 1,
42, 140, 206]
Figure 2: bbs-issuer-private-octets
The protected header used is:
{
"iss": "https://issuer.example",
"claims": [
"family_name",
"given_name",
"email",
"age"
],
"typ": "JPT",
"alg": "BBS-X"
}
Figure 3: bbs-issuer-protected-header
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The first payload is the string "Doe" with the octet sequence of [
34, 68, 111, 101, 34 ] and base64url-encoded as IkRvZSI.
The second payload is the string "Jay" with the octet sequence of [
34, 74, 97, 121, 34 ] and base64url-encoded as IkpheSI.
The third payload is the string "jaydoe@example.org" with the octet
sequence of [ 34, 106, 97, 121, 100, 111, 101, 64, 101, 120, 97, 109,
112, 108, 101, 46, 111, 114, 103, 34 ] and base64url-encoded as
ImpheWRvZUBleGFtcGxlLm9yZyI.
The fourth payload is the string 42 with the octet sequence of [ 52,
50 ] and base64url-encoded as NDI.
The message array used as an input to the BLS implementation is:
[
[123, 34, 105, 115, 115, 34, 58, 34, 104, 116, 116, 112, 115, 58,
47, 47, 105, 115, 115, 117, 101, 114, 46, 101, 120, 97, 109, 112,
108, 101, 34, 44, 34, 99, 108, 97, 105, 109, 115, 34, 58, 91, 34,
102, 97, 109, 105, 108, 121, 95, 110, 97, 109, 101, 34, 44, 34,
103, 105, 118, 101, 110, 95, 110, 97, 109, 101, 34, 44, 34, 101,
109, 97, 105, 108, 34, 44, 34, 97, 103, 101, 34, 93, 44, 34, 116,
121, 112, 34, 58, 34, 74, 80, 84, 34, 44, 34, 97, 108, 103, 34, 58,
34, 66, 66, 83, 45, 88, 34, 125],
[ 34, 68, 111, 101, 34 ],
[ 34, 74, 97, 121, 34 ],
[34, 106, 97, 121, 100, 111, 101, 64, 101, 120, 97, 109, 112, 108,
101, 46, 111, 114, 103, 34], [ 52, 50 ]
]
Figure 4: bbs-issuer-messages
Using the above inputs, the output of the blsSign() call is the octet
string:
[180, 3, 66, 254, 9, 205, 20, 88, 175, 82, 90, 34, 26, 178, 80, 225,
91, 209, 120, 23, 185, 159, 76, 73, 189, 236, 115, 141, 31, 83, 43,
42, 186, 247, 196, 236, 70, 19, 123, 80, 249, 146, 237, 172, 48,
208, 193, 62, 100, 59, 154, 22, 52, 165, 184, 250, 71, 52, 106, 233,
26, 240, 251, 214, 122, 133, 61, 241, 70, 127, 83, 240, 112, 130,
181, 151, 160, 214, 43, 213, 83, 211, 238, 191, 1, 65, 135, 147,
226, 197, 24, 104, 183, 9, 141, 207, 21, 106, 136, 161, 115, 142, 3,
196, 155, 52, 174, 205, 212, 13, 174, 220]
Figure 5: bbs-issuer-signature
The resulting signed JWP in JSON serialization is:
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{
"protected": "eyJpc3MiOiJodHRwczovL2lzc3Vlci5leGFtcGxlIiwiY2xhaW1z
IjpbImZhbWlseV9uYW1lIiwiZ2l2ZW5fbmFtZSIsImVtYWlsIiwiYWdlIl0sInR5cC
I6IkpQVCIsImFsZyI6IkJCUy1YIn0",
"payloads": [
"IkRvZSI",
"IkpheSI",
"ImpheWRvZUBleGFtcGxlLm9yZyI",
"NDI"
],
"proof": "tANC_gnNFFivUloiGrJQ4VvReBe5n0xJvexzjR9TKyq698TsRhN7UPmS
7aww0ME-ZDuaFjSluPpHNGrpGvD71nqFPfFGf1PwcIK1l6DWK9VT0-6_AUGHk-LFGG
i3CY3PFWqIoXOOA8SbNK7N1A2u3A"
}
Figure 6: bbs-issued-jwp
The same JWP in compact serialization:
ImV5SnBjM01pT2lKb2RIUndjem92TDJsemMzVmxjaTVsZUdGdGNHeGxJaXdpWTJ4aGFX
MXpJanBiSW1aaGJXbHNlVjl1WVcxbElpd2laMmwyWlc1ZmJtRnRaU0lzSW1WdFlXbHNJ
aXdpWVdkbElsMHNJblI1Y0NJNklrcFFWQ0lzSW1Gc1p5STZJa0pDVXkxWUluMCI.IkRv
ZSI~IkpheSI~ImpheWRvZUBleGFtcGxlLm9yZyI~NDI.tANC_gnNFFivUloiGrJQ4VvR
eBe5n0xJvexzjR9TKyq698TsRhN7UPmS7aww0ME-ZDuaFjSluPpHNGrpGvD71nqFPfFG
f1PwcIK1l6DWK9VT0-6_AUGHk-LFGGi3CY3PFWqIoXOOA8SbNK7N1A2u3A
Figure 7: bbs-issued-compact
For verification, a nonce is needed:
[137, 103, 248, 147, 211, 133, 97, 190, 130, 157, 110, 64, 244, 250,
100, 151, 7, 36, 164, 109, 146, 195, 190, 75, 32, 255, 6, 128, 44,
128, 96, 9]
Figure 8: bbs-present-nonce
To generate a proof, the blsCreateProof() method is used with a
revealed indexes array argument of [ 0, 2, 4 ] and results in the
octet string:
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[0, 5, 21, 169, 73, 242, 49, 111, 234, 26, 186, 194, 204, 174, 241,
30, 165, 50, 117, 236, 144, 95, 147, 186, 219, 190, 135, 205, 66,
179, 227, 86, 151, 246, 174, 234, 204, 46, 171, 249, 225, 198, 135,
81, 131, 225, 141, 217, 47, 217, 127, 176, 15, 98, 110, 233, 74,
220, 230, 27, 201, 117, 114, 211, 41, 183, 44, 64, 185, 45, 140,
153, 49, 73, 199, 93, 208, 248, 212, 175, 106, 199, 83, 255, 128,
77, 152, 250, 166, 101, 78, 248, 10, 106, 236, 24, 238, 21, 34, 134,
128, 186, 132, 153, 123, 86, 88, 156, 246, 203, 23, 253, 248, 217,
233, 1, 168, 208, 12, 193, 222, 142, 90, 28, 223, 241, 130, 164,
144, 83, 0, 15, 165, 25, 156, 145, 243, 39, 88, 249, 246, 185, 152,
3, 220, 72, 180, 0, 0, 0, 116, 133, 180, 58, 53, 105, 120, 124, 227,
160, 78, 229, 74, 209, 111, 164, 101, 183, 86, 122, 212, 126, 90,
23, 228, 109, 184, 73, 75, 114, 177, 142, 178, 89, 107, 100, 189,
187, 74, 143, 167, 218, 186, 193, 189, 247, 14, 134, 40, 0, 0, 0, 2,
5, 130, 120, 86, 255, 28, 33, 145, 20, 149, 195, 8, 4, 200, 212,
178, 67, 147, 230, 174, 192, 9, 158, 94, 179, 144, 63, 60, 82, 255,
216, 4, 85, 108, 209, 194, 209, 177, 106, 69, 215, 235, 177, 83,
244, 1, 195, 102, 135, 99, 20, 121, 7, 252, 26, 187, 206, 16, 250,
134, 1, 255, 197, 92, 130, 105, 241, 175, 35, 22, 210, 101, 158,
113, 214, 222, 3, 4, 168, 188, 251, 34, 213, 211, 224, 150, 147, 38,
164, 229, 151, 226, 223, 188, 181, 180, 204, 228, 58, 107, 55, 232,
148, 180, 199, 42, 181, 127, 59, 233, 234, 188, 0, 0, 0, 4, 93, 196,
31, 38, 151, 105, 231, 46, 228, 46, 86, 196, 136, 212, 175, 170, 83,
21, 78, 19, 224, 211, 122, 7, 92, 71, 17, 171, 66, 122, 56, 130, 45,
19, 172, 217, 65, 63, 246, 39, 6, 30, 77, 132, 86, 36, 41, 3, 234,
72, 146, 200, 101, 150, 159, 108, 140, 15, 195, 57, 249, 154, 191,
204, 91, 30, 159, 32, 157, 24, 3, 110, 90, 102, 99, 206, 42, 58, 1,
181, 215, 85, 29, 32, 131, 46, 76, 25, 5, 43, 203, 32, 215, 167,
169, 108, 56, 174, 146, 51, 174, 40, 190, 22, 37, 93, 156, 245,
208, 26, 55, 180, 135, 115, 70, 96, 106, 243, 213, 131, 196, 63,
165, 42, 157, 22, 94, 46]
Figure 9: bbs-present-proof
The resulting verifiable JWP in JSON serialization is:
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{
"protected": "eyJpc3MiOiJodHRwczovL2lzc3Vlci5leGFtcGxlIiwiY2xhaW1z
IjpbImZhbWlseV9uYW1lIiwiZ2l2ZW5fbmFtZSIsImVtYWlsIiwiYWdlIl0sInR5cC
I6IkpQVCIsImFsZyI6IkJCUy1YIn0",
"payloads": [
null,
"IkpheSI",
null,
"NDI"
],
"proof": "AAUVqUnyMW_qGrrCzK7xHqUydeyQX5O6276HzUKz41aX9q7qzC6r-eHG
h1GD4Y3ZL9l_sA9ibulK3OYbyXVy0ym3LEC5LYyZMUnHXdD41K9qx1P_gE2Y-qZlTv
gKauwY7hUihoC6hJl7Vlic9ssX_fjZ6QGo0AzB3o5aHN_xgqSQUwAPpRmckfMnWPn2
uZgD3Ei0AAAAdIW0OjVpeHzjoE7lStFvpGW3VnrUfloX5G24SUtysY6yWWtkvbtKj6
fausG99w6GKAAAAAIFgnhW_xwhkRSVwwgEyNSyQ5PmrsAJnl6zkD88Uv_YBFVs0cLR
sWpF1-uxU_QBw2aHYxR5B_wau84Q-oYB_8VcgmnxryMW0mWecdbeAwSovPsi1dPglp
MmpOWX4t-8tbTM5DprN-iUtMcqtX876eq8AAAABF3EHyaXaecu5C5WxIjUr6pTFU4T
4NN6B1xHEatCejiCLROs2UE_9icGHk2EViQpA-pIkshllp9sjA_DOfmav8xbHp8gnR
gDblpmY84qOgG111UdIIMuTBkFK8sg16epbDiukjOuKL4WJV2c9dAaN7SHc0ZgavPV
g8Q_pSqdFl4u"
}
Figure 10: bbs-present-jwp
The same JWP in compact serialization:
ImV5SnBjM01pT2lKb2RIUndjem92TDJsemMzVmxjaTVsZUdGdGNHeGxJaXdpWTJ4aGFX
MXpJanBiSW1aaGJXbHNlVjl1WVcxbElpd2laMmwyWlc1ZmJtRnRaU0lzSW1WdFlXbHNJ
aXdpWVdkbElsMHNJblI1Y0NJNklrcFFWQ0lzSW1Gc1p5STZJa0pDVXkxWUluMCI.~Ikp
heSI~~NDI.AAUVqUnyMW_qGrrCzK7xHqUydeyQX5O6276HzUKz41aX9q7qzC6r-eHGh1
GD4Y3ZL9l_sA9ibulK3OYbyXVy0ym3LEC5LYyZMUnHXdD41K9qx1P_gE2Y-qZlTvgKau
wY7hUihoC6hJl7Vlic9ssX_fjZ6QGo0AzB3o5aHN_xgqSQUwAPpRmckfMnWPn2uZgD3E
i0AAAAdIW0OjVpeHzjoE7lStFvpGW3VnrUfloX5G24SUtysY6yWWtkvbtKj6fausG99w
6GKAAAAAIFgnhW_xwhkRSVwwgEyNSyQ5PmrsAJnl6zkD88Uv_YBFVs0cLRsWpF1-uxU_
QBw2aHYxR5B_wau84Q-oYB_8VcgmnxryMW0mWecdbeAwSovPsi1dPglpMmpOWX4t-8tb
TM5DprN-iUtMcqtX876eq8AAAABF3EHyaXaecu5C5WxIjUr6pTFU4T4NN6B1xHEatCej
iCLROs2UE_9icGHk2EViQpA-pIkshllp9sjA_DOfmav8xbHp8gnRgDblpmY84qOgG111
UdIIMuTBkFK8sg16epbDiukjOuKL4WJV2c9dAaN7SHc0ZgavPVg8Q_pSqdFl4u
Figure 11: bbs-present-compact
6.3. Message Authentication Code
The Message Authentication Code (MAC) JPA uses a MAC to both generate
ephemeral keys and compute authentication codes to protect the issuer
header and each payload individually.
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Like the JWS-based JPA, it also does not support unlinkability if the
same JWP is presented multiple times and requires an individually
issued JWP for each presentation in order to fully protect privacy.
When compared to the JWS approach, using a MAC requires less
computation but can result in potentially larger presentation proof
values.
The design is intentionally minimal and only involves using a single
standardized MAC method instead of a mix of MAC/hash methods or a
custom hash-based construct. It is able to use any published
cryptographic MAC method such as HMAC
(https://datatracker.ietf.org/doc/html/rfc2104) or KMAC
(https://nvlpubs.nist.gov/nistpubs/SpecialPublications/
NIST.SP.800-185.pdf). It uses traditional public-key based
signatures to verify the authenticity of the issuer and holder.
6.3.1. Holder Setup
Prior to the issuer creating a new JWP it must have presentation
binding information provided by the holder. This enables the holder
to perform replay prevention while presenting the JWP.
The presentation key used by the holder must be transferred to the
issuer and verified, likely through a challenge and self-signing
mechanism. If the holder requires unlinkability it must also
generate a new key that is verified and bound to each new JWP.
How these holder presentation keys are transferred and verified is
out of scope of this specification, protocols such as OpenID Connect
can be used to accomplish this. What is required by this definition
is that the holder's presentation key MUST be included in the
issuer's protected header using the pjwk claim with a JWK as the
value.
6.3.2. Issuer Setup
To use the MAC algorithm the issuer must have a stable public key
pair to perform signing. To start the issuance process, a single
32-byte random Shared Secret must first be generated. This value
will be shared privately to the holder as part of the issuer's JWP
proof value.
The Shared Secret is used by both the issuer and holder as the MAC
method's key to generate a new set of unique ephemeral keys. These
keys are then used as the input to generate a MAC that protects each
payload.
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6.3.3. Issuer Protected Header
The holder's presentation key JWK MUST be included in the issuer
protected header using the pjwk claim. The issuer MUST validate that
the holder has possession of this key through a trusted mechanism
such as verifying the signature of a unique nonce value from the
holder.
For consistency, the issuer header is also protected by a MAC by
using the fixed value "issuer_header" as the input key. The issuer
header JSON is serialized using UTF-8 and encoded with base64url into
an octet array. The final issuer header MAC is generated from the
octet array and the fixed key, and the resulting value becomes the
first input into the larger octet array that will be signed by the
issuer.
6.3.4. Payloads
A unique key is generated for each payload using the MAC with the
Shared Secret as the key and the values "payload_X" where "X" is
replaced by the zero-based array index of the payload, for example
"payload_0", "payload_1", etc.
Each payload is serialized using UTF-8 and encoded with base64url
into an octet array. The generated key for that payload based on its
index is used to generate the MAC for the payload's encoded octet
array. The resulting value is appended to the larger octet array
that will be signed by the issuer.
6.3.5. Issuer Proof
The issuer proof consists of two items appended together, the
issuer's signature of the appended array of MACs, and the Shared
Secret used to generate the set of payload keys.
To generate the signature, the array containing the final MAC of the
issuer protected header followed by all of the payload MACs appended
in order is used as the input to a new JWS.
jws_payload = [issuer_header_mac, payload_mac_1, ... payload_mac_n]
The issuer signs the JWS using its stable public key and a fixed
header containing the alg associated with MAC algorithm in use.
jws_header = '{"alg":"ES256"}'
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The resulting signature is decoded and used as the first item in the
issuer proof value. The octet array of the Shared Secret is
appended, resulting in the final issuer proof value.
issuer_proof = [jws_signature, shared_secret]
6.3.6. Presentation Protected Header
See the JWS Presentation Protected Header (#presentation-protected-
header) section.
6.3.7. Presentation
| Editor's Note: The current definition here is incomplete, the
| holder's signature needs to also incorporate the presented proof.
The presentation proof is constructed as a large octet array
containing multiple appended items similar to the issuer proof value.
The first item is the JWS decoded signature value generated when the
holder uses the presentation key to sign the presentation header.
The second item is the issuer signature from the issuer's proof
value.
These two signatures are then followed by a MAC value for each
payload. The MAC values used will depend on if that payload has been
disclosed or is hidden. Disclosed payloads will include the MAC key
input, and hidden payloads will include only their final MAC value.
presentation_proof = [presentation_signature, issuer_signature,
disclosed_key_0, hidden_mac_1, hidden_mac_2,
... disclosed_key_n]
The size of this value will depend on the underlying cryptographic
algorithms. For example, MAC-H256 uses the ES256 JWS with a decoded
signature of 64 octets, and for a JWP with five payloads using HMAC-
SHA256 the total presentation proof value length would be 64 + 64 +
(5 * 32) = 288 octets.
6.3.8. Verifier Setup
In order to verify that the presentation was protected from replay
attacks, the verifier must be able to validate the presentation
protected header. This involves the following steps:
1. JSON parse the presentation header
2. Validate the contained nonce claim
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3. JSON parse the issuer header
4. Validate the contained pjwk claim
5. Create a JWS using the correct fixed header with alg value and
the presentation header as the body
6. Remove the presentation_signature from the beginning of the
presentation_proof octet array
7. Validate the JWS using the JWK from the pjwk claim and the
presentation_signature value
Next, the verifier must validate all of the disclosed payloads using
the following steps:
1. JSON parse the issuer header
2. Resolve the kid using a trusted mechanism to obtain the correct
issuer JWK
3. Remove the issuer_signature from the beginning of the remaining
presentation_proof octet array (after the presentation_signature
was removed)
4. Perform the MAC on the presented issuer_header value using the
"issuer_header" value as the input key
5. Store the resulting value as the first entry in a new jws_payload
octet array
6. Iterate on each presented payload (disclosed or hidden)
1. Extract the next hash value from the remaining
presentation_proof octet array
2. If the payload was disclosed: perform a MAC using the given
hash value as the input key and append the result to the
jws_payload octet array
3. If the payload was hidden: append the given hash value to the
jws_payload octet array
7. Create a JWS using a header containing the alg parameter along
with the generated jws_payload value as the payload
8. Validate the JWS using the resolved issuer JWK and the extracted
issuer_signature value
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6.3.9. JPA Registration
Proposed JWP alg value is of the format "MAC-" appended with a unique
identifier for the set of MAC and signing algorithms used. Below are
the initial registrations:
* MAC-H256 uses HMAC SHA-256 as the MAC and ECDSA using P-256 and
SHA-256 for the signatures
* MAC-H384 uses HMAC SHA-384 as the MAC and ECDSA using P-384 and
SHA-384 for the signatures
* MAC-H512 uses HMAC SHA-512 as the MAC and ECDSA using P-521 and
SHA-512 for the signatures
* MAC-K25519 uses KMAC SHAKE128 as the MAC and EdDSA using
Curve25519 for the signatures
* MAC-K448 uses KMAC SHAKE256 as the MAC and EdDSA using Curve448
for the signatures
* MAC-H256K uses HMAC SHA-256 as the MAC and ECDSA using secp256k1
and SHA-256 for the signatures
6.3.10. Example
The following example uses the MAC-H256 algorithm.
This is the Signer's stable private key in the JWK format:
{
"crv": "P-256",
"kty": "EC",
"x": "ONebN43-G5DOwZX6jCVpEYEe0bYd5WDybXAG0sL3iDA",
"y": "b0MHuYfSxu3Pj4DAyDXabAc0mPjpB1worEpr3yyrft4",
"d": "jnE0-9YvxQtLJEKcyUHU6HQ3Y9nSDnh0NstYJFn7RuI"
}
Figure 12: issuer-private-jwk
This is the Signer's generated Shared Secret:
[100, 109, 91, 184, 139, 20, 107, 86, 1, 252, 86, 159, 126, 251,
228, 4, 35, 177, 75, 96, 11, 205, 144, 189, 42, 95, 135, 170, 107,
58, 99, 142]
Figure 13: mac-shared-secret
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This is the Holder's presentation private key in the JWK format:
{
"crv": "P-256",
"kty": "EC",
"x": "oB1TPrE_QJIL61fUOOK5DpKgd8j2zbZJtqpILDTJX6I",
"y": "3JqnrkucLobkdRuOqZXOP9MMlbFyenFOLyGlG-FPACM",
"d": "AvyDPl1I4xwjrI2iEOi6DxM9ipJe_h_VUN5OvoKvvW8"
}
Figure 14: holder-presentation-jwk
The first MAC is generated using the key issuer_header and the
base64url-encoded issuer protected header, resulting in this octet
array:
[140, 88, 59, 30, 127, 113, 27, 237, 78, 200, 182, 114, 94, 123,
198, 128, 102, 232, 178, 88, 252, 248, 57, 2, 231, 19, 145, 8, 160,
197, 66, 166]
Figure 15: mac-issuer-header-mac
The issuer generates an array of derived keys with one for each
payload by using the shared secret as the key and the index of the
payload as the input:
[
[180, 129, 55, 94, 125, 158, 179, 245, 30, 199, 148, 60, 184, 28,
197, 123, 231, 232, 95, 91, 65, 74, 38, 242, 253, 96, 67, 44, 40,
220, 250, 4],
[143, 172, 182, 156, 184, 138, 228, 172, 215, 26, 175, 137, 137,
25, 159, 141, 213, 12, 214, 29, 231, 200, 13, 94, 116, 22, 41, 115,
72, 214, 57, 98],
[144, 73, 77, 66, 230, 187, 217, 186, 246, 41, 138, 25, 39, 203,
101, 76, 156, 161, 244, 130, 203, 166, 184, 154, 7, 4, 218, 84,
168, 199, 36, 245],
[70, 55, 182, 105, 101, 130, 254, 234, 68, 224, 219, 97, 119, 98,
244, 33, 43, 55, 148, 238, 225, 177, 101, 160, 49, 246, 109, 155,
242, 236, 21, 138]
]
Figure 16: mac-issuer-keys
The first payload is the string "Doe" with the octet sequence of [
34, 68, 111, 101, 34 ] and base64url-encoded as IkRvZSI.
The second payload is the string "Jay" with the octet sequence of [
34, 74, 97, 121, 34 ] and base64url-encoded as IkpheSI.
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The third payload is the string "jaydoe@example.org" with the octet
sequence of [ 34, 106, 97, 121, 100, 111, 101, 64, 101, 120, 97, 109,
112, 108, 101, 46, 111, 114, 103, 34 ] and base64url-encoded as
ImpheWRvZUBleGFtcGxlLm9yZyI.
The fourth payload is the string 42 with the octet sequence of [ 52,
50 ] and base64url-encoded as NDI.
A MAC is generated for each payload using the generated key for its
given index, resulting in an array of MACs:
[
[156, 53, 90, 125, 139, 226, 60, 168, 100, 220, 79, 255, 8, 87, 28,
220, 237, 112, 161, 91, 39, 68, 137, 203, 92, 243, 16, 116, 64,
129, 61, 172],
[239, 17, 12, 35, 111, 129, 51, 87, 43, 86, 234, 38, 89, 149, 169,
157, 33, 104, 81, 246, 190, 154, 74, 195, 194, 158, 50, 208, 203,
203, 249, 237],
[162, 174, 12, 27, 190, 250, 112, 1, 139, 177, 49, 124, 110, 201,
83, 233, 14, 109, 60, 253, 121, 184, 126, 121, 26, 138, 5, 214, 97,
96, 216, 80],
[61, 109, 78, 172, 255, 189, 67, 83, 247, 65, 234, 128, 30, 47,
145, 70, 129, 26, 41, 41, 78, 4, 151, 230, 232, 127, 135, 230, 14,
208, 178, 50]
]
Figure 17: mac-issuer-macs
Concatenating the issuer protected header MAC with the array of
payload MACs produces a single octet array that is signed using the
issuer's stable key, resulting in the following signature:
[120, 172, 15, 230, 138, 230, 150, 139, 241, 196, 79, 134, 122, 43,
149, 11, 253, 104, 58, 199, 49, 87, 32, 64, 237, 50, 86, 155, 153,
58, 63, 116, 245, 130, 136, 197, 164, 207, 232, 238, 106, 171, 246,
98, 149, 254, 22, 1, 114, 187, 233, 168, 116, 173, 211, 208, 234,
245, 76, 238, 143, 157, 83, 202]
Figure 18: mac-issuer-signature
The original shared secret octet string is then concatenated to the
end of the issuer signature octet string and the result is base64url-
encoded as the issuer's proof value.
The final issued JWP in JSON serialization is:
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{
"payloads": [
"IkRvZSI",
"IkpheSI",
"ImpheWRvZUBleGFtcGxlLm9yZyI",
"NDI"
],
"issuer": "eyJpc3MiOiJodHRwczovL2lzc3Vlci50bGQiLCJjbGFpbXMiOlsiZmF
taWx5X25hbWUiLCJnaXZlbl9uYW1lIiwiZW1haWwiLCJhZ2UiXSwidHlwIjoiSlBUI
iwicGp3ayI6eyJjcnYiOiJQLTI1NiIsImt0eSI6IkVDIiwieCI6Im9CMVRQckVfUUp
JTDYxZlVPT0s1RHBLZ2Q4ajJ6YlpKdHFwSUxEVEpYNkkiLCJ5IjoiM0pxbnJrdWNMb
2JrZFJ1T3FaWE9QOU1NbGJGeWVuRk9MeUdsRy1GUEFDTSJ9LCJhbGciOiJNQUMtSDI
1NiJ9",
"proof": "eKwP5ormlovxxE-GeiuVC_1oOscxVyBA7TJWm5k6P3T1gojFpM_o7mqr
9mKV_hYBcrvpqHSt09Dq9Uzuj51TymRtW7iLFGtWAfxWn3775AQjsUtgC82QvSpfh6
prOmOO"
}
Figure 19: mac-issued-jwp
The same JWP in compact serialization:
eyJpc3MiOiJodHRwczovL2lzc3Vlci50bGQiLCJjbGFpbXMiOlsiZmFtaWx5X25hbWUi
LCJnaXZlbl9uYW1lIiwiZW1haWwiLCJhZ2UiXSwidHlwIjoiSlBUIiwicGp3ayI6eyJj
cnYiOiJQLTI1NiIsImt0eSI6IkVDIiwieCI6Im9CMVRQckVfUUpJTDYxZlVPT0s1RHBL
Z2Q4ajJ6YlpKdHFwSUxEVEpYNkkiLCJ5IjoiM0pxbnJrdWNMb2JrZFJ1T3FaWE9QOU1N
bGJGeWVuRk9MeUdsRy1GUEFDTSJ9LCJhbGciOiJNQUMtSDI1NiJ9.IkRvZSI~IkpheSI
~ImpheWRvZUBleGFtcGxlLm9yZyI~NDI.eKwP5ormlovxxE-GeiuVC_1oOscxVyBA7TJ
Wm5k6P3T1gojFpM_o7mqr9mKV_hYBcrvpqHSt09Dq9Uzuj51TymRtW7iLFGtWAfxWn37
75AQjsUtgC82QvSpfh6prOmOO
Figure 20: mac-issued-compact
Next, we show the presentation of the JWP with selective disclosure.
We start with this presentation header using a nonce provided by the
Verifier:
{
"nonce": "uTEB371l1pzWJl7afB0wi0HWUNk1Le-bComFLxa8K-s"
}
Figure 21: mac-presentation-header
When signed with the holder's presentation key, the resulting
signature octets are:
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[126, 134, 175, 2, 165, 12, 103, 11, 116, 72, 94, 228, 240, 142,
107, 195, 198, 238, 218, 203, 63, 198, 105, 175, 1, 69, 182, 5, 204,
239, 35, 149, 85, 55, 4, 169, 109, 243, 88, 213, 12, 1, 167, 235,
222, 17, 232, 118, 110, 111, 47, 165, 102, 142, 0, 1, 226, 117, 143,
125, 132, 62, 231, 145]
Figure 22: mac-presentation-header-signature
Then by applying selective disclosure of only the given name and age
claims (family name and email hidden, payload array indexes 0 and 2),
the holder builds a mixed array of either the payload key (if
disclosed) or MAC (if hidden):
[
[156, 53, 90, 125, 139, 226, 60, 168, 100, 220, 79, 255, 8, 87, 28,
220, 237, 112, 161, 91, 39, 68, 137, 203, 92, 243, 16, 116, 64,
129, 61, 172],
[143, 172, 182, 156, 184, 138, 228, 172, 215, 26, 175, 137, 137,
25, 159, 141, 213, 12, 214, 29, 231, 200, 13, 94, 116, 22, 41, 115,
72, 214, 57, 98],
[162, 174, 12, 27, 190, 250, 112, 1, 139, 177, 49, 124, 110, 201,
83, 233, 14, 109, 60, 253, 121, 184, 126, 121, 26, 138, 5, 214, 97,
96, 216, 80],
[70, 55, 182, 105, 101, 130, 254, 234, 68, 224, 219, 97, 119, 98,
244, 33, 43, 55, 148, 238, 225, 177, 101, 160, 49, 246, 109, 155,
242, 236, 21, 138]
]
Figure 23: mac-presentation-keyormac
The final presented proof value is generated by concatenating first
the presentation header signature octet string, followed by the
issuer signature octet string, then followed by the mixed array of
keys and MACs:
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[126, 134, 175, 2, 165, 12, 103, 11, 116, 72, 94, 228, 240, 142,
107, 195, 198, 238, 218, 203, 63, 198, 105, 175, 1, 69, 182, 5, 204,
239, 35, 149, 85, 55, 4, 169, 109, 243, 88, 213, 12, 1, 167, 235,
222, 17, 232, 118, 110, 111, 47, 165, 102, 142, 0, 1, 226, 117, 143,
125, 132, 62, 231, 145, 120, 172, 15, 230, 138, 230, 150, 139, 241,
196, 79, 134, 122, 43, 149, 11, 253, 104, 58, 199, 49, 87, 32, 64,
237, 50, 86, 155, 153, 58, 63, 116, 245, 130, 136, 197, 164, 207,
232, 238, 106, 171, 246, 98, 149, 254, 22, 1, 114, 187, 233, 168,
116, 173, 211, 208, 234, 245, 76, 238, 143, 157, 83, 202, 156, 53,
90, 125, 139, 226, 60, 168, 100, 220, 79, 255, 8, 87, 28, 220, 237,
112, 161, 91, 39, 68, 137, 203, 92, 243, 16, 116, 64, 129, 61, 172,
143, 172, 182, 156, 184, 138, 228, 172, 215, 26, 175, 137, 137, 25,
159, 141, 213, 12, 214, 29, 231, 200, 13, 94, 116, 22, 41, 115, 72,
214, 57, 98, 162, 174, 12, 27, 190, 250, 112, 1, 139, 177, 49, 124,
110, 201, 83, 233, 14, 109, 60, 253, 121, 184, 126, 121, 26, 138, 5,
214, 97, 96, 216, 80, 70, 55, 182, 105, 101, 130, 254, 234, 68, 224,
219, 97, 119, 98, 244, 33, 43, 55, 148, 238, 225, 177, 101, 160, 49,
246, 109, 155, 242, 236, 21, 138]
Figure 24: mac-presentation-proof
The resulting presented JWP in JSON serialization is:
{
"payloads": [
null,
"IkpheSI",
null,
"NDI"
],
"issuer": "eyJpc3MiOiJodHRwczovL2lzc3Vlci50bGQiLCJjbGFpbXMiOlsiZmF
taWx5X25hbWUiLCJnaXZlbl9uYW1lIiwiZW1haWwiLCJhZ2UiXSwidHlwIjoiSlBUI
iwicGp3ayI6eyJjcnYiOiJQLTI1NiIsImt0eSI6IkVDIiwieCI6Im9CMVRQckVfUUp
JTDYxZlVPT0s1RHBLZ2Q4ajJ6YlpKdHFwSUxEVEpYNkkiLCJ5IjoiM0pxbnJrdWNMb
2JrZFJ1T3FaWE9QOU1NbGJGeWVuRk9MeUdsRy1GUEFDTSJ9LCJhbGciOiJNQUMtSDI
1NiJ9",
"proof": "foavAqUMZwt0SF7k8I5rw8bu2ss_xmmvAUW2BczvI5VVNwSpbfNY1QwB
p-veEeh2bm8vpWaOAAHidY99hD7nkXisD-aK5paL8cRPhnorlQv9aDrHMVcgQO0yVp
uZOj909YKIxaTP6O5qq_Zilf4WAXK76ah0rdPQ6vVM7o-dU8qcNVp9i-I8qGTcT_8I
Vxzc7XChWydEictc8xB0QIE9rI-stpy4iuSs1xqviYkZn43VDNYd58gNXnQWKXNI1j
lioq4MG776cAGLsTF8bslT6Q5tPP15uH55GooF1mFg2FBGN7ZpZYL-6kTg22F3YvQh
KzeU7uGxZaAx9m2b8uwVig",
"presentation": "eyJub25jZSI6InVURUIzNzFsMXB6V0psN2FmQjB3aTBIV1VOa
zFMZS1iQ29tRkx4YThLLXMifQ"
}
Figure 25: mac-presentation-jwp
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The same JWP in compact serialization:
eyJpc3MiOiJodHRwczovL2lzc3Vlci50bGQiLCJjbGFpbXMiOlsiZmFtaWx5X25hbWUi
LCJnaXZlbl9uYW1lIiwiZW1haWwiLCJhZ2UiXSwidHlwIjoiSlBUIiwicGp3ayI6eyJj
cnYiOiJQLTI1NiIsImt0eSI6IkVDIiwieCI6Im9CMVRQckVfUUpJTDYxZlVPT0s1RHBL
Z2Q4ajJ6YlpKdHFwSUxEVEpYNkkiLCJ5IjoiM0pxbnJrdWNMb2JrZFJ1T3FaWE9QOU1N
bGJGeWVuRk9MeUdsRy1GUEFDTSJ9LCJhbGciOiJNQUMtSDI1NiJ9.eyJub25jZSI6InV
URUIzNzFsMXB6V0psN2FmQjB3aTBIV1VOazFMZS1iQ29tRkx4YThLLXMifQ.~IkpheSI
~~NDI.foavAqUMZwt0SF7k8I5rw8bu2ss_xmmvAUW2BczvI5VVNwSpbfNY1QwBp-veEe
h2bm8vpWaOAAHidY99hD7nkXisD-aK5paL8cRPhnorlQv9aDrHMVcgQO0yVpuZOj909Y
KIxaTP6O5qq_Zilf4WAXK76ah0rdPQ6vVM7o-dU8qcNVp9i-I8qGTcT_8IVxzc7XChWy
dEictc8xB0QIE9rI-stpy4iuSs1xqviYkZn43VDNYd58gNXnQWKXNI1jlioq4MG776cA
GLsTF8bslT6Q5tPP15uH55GooF1mFg2FBGN7ZpZYL-6kTg22F3YvQhKzeU7uGxZaAx9m
2b8uwVig
Figure 26: mac-presentation-compact
6.4. ZKSnark
| Editor's Note: This is just a placeholder for a future definition
| that is in the early stages of development as part of the
| Decentralized Identity Foundation (https://github.com/
| decentralized-identity/spartan_zkSNARK_signatures).
7. Security Considerations
| Editor's Note: This will follow once the algorithms defined here
| have become more stable.
* Data minimization of the proof value
* Unlinkability of the protected header contents
8. IANA Considerations
8.1. JWP Algorithms Registry
This section establishes the IANA JWP Algorithms Registry. It also
registers the following algorithms.
TBD
9. Informative References
[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/info/rfc2119>.
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[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, <https://www.rfc-editor.org/info/rfc7515>.
[RFC7518] Jones, M., "JSON Web Algorithms (JWA)", RFC 7518,
DOI 10.17487/RFC7518, May 2015,
<https://www.rfc-editor.org/info/rfc7518>.
[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/info/rfc8174>.
Appendix A. Acknowledgements
TBD
Appendix B. Document History
[[ To be removed from the final specification ]]
-01
* Applied editorial improvements
-00
* First individual draft targeting JOSE working group
Authors' Addresses
Jeremie Miller
Ping Identity
Email: jmiller@pingidentity.com
Michael B. Jones
Microsoft
Email: mbj@microsoft.com
URI: https://self-issued.info/
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