| Internet-Draft | json-proof-algorithms | July 2025 |
| Jones, et al. | Expires 8 January 2026 | [Page] |
The JSON Proof Algorithms (JPA) specification registers cryptographic algorithms and identifiers to be used with the JSON Web Proof, JSON Web Key (JWK), and COSE specifications. It defines IANA registries for these identifiers.¶
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/.¶
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This Internet-Draft will expire on 8 January 2026.¶
Copyright (c) 2025 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.¶
The JSON Web Proof (JWP) [I-D.ietf-jose-json-web-proof] 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 welcomed at https://github.com/ietf-wg-jose/json-web-proof.¶
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 VC Data Model [VC-DATA-MODEL-2.0]. The term "presentation" is also used as defined by this source, but the term "credential" is avoided in this specification to minimize confusion with other definitions.¶
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 [I-D.ietf-jose-json-web-proof].¶
These terms are defined by this specification:¶
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.¶
The four principal interactions that every proof algorithm MUST support are issue, confirm, present, and verify.¶
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.¶
Performed by the holder to validate that the issued JWP is correctly formed and protected.¶
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.¶
Used to apply any selective disclosure choices and perform any unlinkability transformations, as well as to show binding.¶
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.¶
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.¶
This section defines how to use specific algorithms for JWPs.¶
The Single Use (SU) algorithm is based on composing multiple traditional asymmetric signatures into a single JWP proof. 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).¶
The Single Use algorithm uses multiple signing keys to protect the protected header as well as individual payloads of an Issued JWP. The issuer uses a stable public key to sign each protected header, and a per-JWP ephemeral key (conveyed within the protected header) to protect the individual payloads. These signatures are all created using the same Asymmetric Algorithm, with the JOSE and COSE name/label of this algorithm being part of registration for a fully-specified Single Use algorithm identifier.¶
The issuer protected header also conveys a holder presentation key, an ephemeral asymmetric key meant to only be used for presenting a single JWP. The fully-specified algorithm the holder must use for presentations is also included. This algorithm MAY be different from the algorithm used by the issuer.¶
The chosen algorithms MUST be asymmetric signing algorithms, so that each signature can be verified without sharing any private values between the parties.¶
In order to support the protection of a presentation by a holder to a verifier, the holder MUST use a Holder Presentation Key during the issuance and the presentation of every Single Use JWP. This Holder Presentation Key MUST be generated and used for only one JWP if unlinkability is desired.¶
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 accomplished by the holder using this key to generate a JWS that signs a value the issuer can verify as unique.¶
The issuer MUST determine an appropriate holder presentation algorithm
corresponding to the holder presentation key. If the holder and
verifier cannot be assumed to know this algorithm is the appropriate
choice for a given holder presentation key, this value MUST be conveyed
in the hpa issuer protected header.¶
To create a Single Use JWP, the issuer first generates a unique Ephemeral Key using the selected internal algorithm. This key-pair will be used to sign each of the payloads of a single JWP and then discarded.¶
Each individual payload is signed using the selected internal algorithm using the Ephemeral Key.¶
The Issuer's Ephemeral Key MUST be included via the Issuer Ephemeral Key header parameter.¶
The Holder's Presentation Key MUST be included via the Holder Presentation Key header parameter.¶
The Holder's Presentation Algorithm MUST be included via the Holder Presentation Algorithm header parameter unless there is another way for the holder and verifier to unambiguously determine the appropriate algorithm to use.¶
The Issuer Protected Header is signed using the appropriate internal signing algorithm for the given fully-specified single use algorithm, using the issuer's Stable Key.¶
Each JWP payload is processed in order and signed using the given JWA using the issuer's Ephemeral Key.¶
The proof value is an octet string array. The first entry is the octet string of the issuer protected header signature, with an additional entry for each payload signature.¶
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 parameter that both the holder and verifier
trust as being unique and non-replayable. Use of the nonce header
parameter is RECOMMENDED for this purpose.¶
This specification registers the nonce header parameter 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 header parameters that are either provided by the verifier or by the holder. These presentation header parameters SHOULD NOT contain values that are common across multiple presentations and SHOULD be unique to a single presentation and verifier.¶
The presentation protected header MUST contain the same Algorithm protected header as the issuer protected header. The Holder Presentation Algorithm protected header MUST NOT be included.¶
The holder derives a new proof as part of presentation. The holder will also use these components to generate a presentation internal representation. The number of components depends on the number of payloads which are being disclosed in the presented JWP.¶
The first proof component will be the signature over the issuer protected header made by the issuer's Stable Key.¶
For each payload which is to be disclosed, the corresponding payload signature (from the issued JWP) is included as a subsequent proof component. If the payload is being omitted, the corresponding payload signature is omitted from the proof components.¶
The holder protected header, issuer protected header, payload slots (distinguishing which are being disclosed) and these proof components are inputs to determine the presentation internal representation.¶
The holder's signature over the presentation internal representation (using the holder's private key and the holder presentation algorithm) is then included as one additional proof component in the final presentation.¶
For example, if only the second and fifth of five payloads are being disclosed, then the proof at this stage will consist of three values:¶
The presentation internal representation would be calculated with these three proof components, while the final presentation would have an additional fourth component containing the signature using the holder's private key.¶
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.¶
Verification is performed using the following steps.¶
The 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".¶
Some algorithms (such as Single use and MAC) use a holder key to provide integrity over the presentation. For these algorithms, an internal binary form of the presentation must be generated both for signing by the holder, and for verification by the verifier. Other algorithms MAY use this same form for consistency.¶
The instructions for creating this binary representation will also create well-formed CBOR, although this data is not meant to be shared outside the implementing algorithm. Instead, it focuses on simplicity of generation by the holder and verifier implementations. Although CBOR has multiple representations of the same underlying information, this same octet string MUST be generated by an implementation.¶
When a length or count is added by the steps below, it is added as its 8
byte, network-ordered representation. For example, the length of a
1,234 byte payload would have a length representation of
0x00 00 00 00 00 00 04 D2.¶
The binary representation is created by appending data into a single octet string in the following order:¶
0x84 5B¶
0x5B¶
0x9B¶
For each payload representation:¶
0x9B¶
The number of proof components as specified by the algorithm¶
For each proof component, append:¶
The BBS Signature Scheme [I-D.irtf-cfrg-bbs-signatures] is under active development within the CRFG.¶
This algorithm supports both selective disclosure and unlinkability, enabling the holder to generate multiple presentations from one issued JWP without a verifier being able to correlate those presentations together based on the proof.¶
The BBS algorithm corresponds to a ciphersuite identifier of
BBS_BLS12381G1_XMD:SHA-256_SSWU_RO_.¶
The key used for the BBS algorithm is an elliptic curve-based key
pair, specifically against the G_2 subgroup of a pairing friendly curve.
Additional details on key generation can be found in
Section 3.4. The JWK and Cose Key
Object representations of the key are detailed in
[I-D.ietf-cose-bls-key-representations].¶
There is no additional holder presentation key necessary for presentation proofs.¶
Issuance is performed using the Sign operation from
Section 3.5.1 of [I-D.irtf-cfrg-bbs-signatures]. This operation
utilizes the issuer's BLS12-381 G2 key pair as SK and PK, along with
desired protected header octets as header, and the array of payload
octet string as messages.¶
The octets resulting from this operation form a single octet string in the issuance proof array, to be used along with the protected header and payloads to serialize the JWP.¶
Holder verification of the signature on issuance form is performed using
the Verify operation from [@!I-D.irtf-cfrg-bbs-signatures, section
3.5.2].¶
This operation utilizes the issuer's public key as PK, the proof as
signature, the protected header octets as header and the array of
payload octets as messages.¶
Derivation of a presentation is done by the holder using the ProofGen
operation from Section 3.5.3 of [I-D.irtf-cfrg-bbs-signatures].¶
This operation utilizes the issuer's public key as PK, the issuer
protected header as header, the issuance proof as signature, the
issuance payloads as messages, and the holder's presentation protected
header as ph.¶
The operation also takes a vector of indexes into messages, describing
which payloads the holder wishes to disclose. All payloads are required
for proof generation, but only these indicated payloads will be required
to be disclosed for later proof verification.¶
The output of this operation is the presentation proof, as a single octet string.¶
Presentation serialization leverages the two protected headers and
presentation proof, along with the disclosed payloads. Non-disclosed
payloads are represented with the absent value of null in CBOR
serialization and a zero-length string in compact serialization.¶
Verification of a presentation is done by the verifier using the
ProofVerify operation from [@!I-D.irtf-cfrg-bbs-signatures, Section
3.5.4].¶
This operation utilizes the issuer's public key as PK, the issuer
protected header as header, the issuance proof as signature, the
holder's presentation protected header as ph, and the payloads as
disclosed_messages.¶
In addition, the disclosed_indexes scalar array is calculated from the
payloads provided. Values disclosed in the presented payloads have a
zero-based index in this array, while the indices of absent payloads are
omitted.¶
The Message Authentication Code (MAC) JPA uses a MAC to both generate ephemeral secrets and to authenticate payloads, along with an asymmetric signature to provide integrity to the issued JWP.¶
The holder can manipulate which payloads are disclosed from the issued JWP, and uses the Holder Presentation Key to create a presentation. The signature created from the Holder Presentation Key MAY use a different algorithm than the Issuer used to sign the issued form.¶
Like the Single Use algorithm family, 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 [RFC2104] or KMAC. It uses traditional public key-based signatures to verify the authenticity of the issuer and holder.¶
In order to support the protection of a presentation by a holder to a verifier, the holder MUST use a Holder Presentation Key during the issuance and the presentation of every MAC JWP. This Holder Presentation Key MUST be generated and used for only one JWP if unlinkability is desired.¶
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 accomplished by the holder using this key to generate a JWS that signs a value the issuer can verify as unique.¶
The holder's presentation key MUST be included in the issuer's protected header using the Holder Presentation Key header parameter.¶
The issuer MUST determine an appropriate holder presentation algorithm corresponding to the holder presentation key. If the holder and verifier cannot be assumed to know this algorithm is the appropriate choice for a given holder presentation key, this value MUST be conveyed in the Holder Protected Algorithm header parameter.¶
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 with 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.¶
The combined MAC representation is a single octet string representing the MAC values of the issuer protected header, along with each payload provided by the issuer. This representation is signed by the issuer, but not shared - parties will recreate this octet string and verify the signature to verify the integrity of supplied issuer protected header and the integrity of any disclosed payloads.¶
The steps below describe a sequential concatenation of binary values to generate the Combined MAC Representation. The instructions for generating this octet string will also generate well-formed CBOR, although this data is not meant to be shared outside the implementing algorithm. Instead, it focuses on simplicity of generation by the issuer, holder, and verifier implementations. Although CBOR has multiple representations of the same underlying information, this same octet string MUST be generated by an implementation.¶
When a length or count is added by steps in this section, it is added as
its 8-byte, network-ordered representation. For example, the length of
a 1,234-byte payload would have a length representation of
0x00 00 00 00 00 00 04 D2.¶
The holder will a unique key per payload value using a MAC, with the Shared Secret as the key and a generated binary value. This binary value is constructed by appending data into a single octet string:¶
The holder will also compute a corresponding MAC of each payload. This MAC uses the unique key above and the payload octet string as the value.¶
When verifying a presentation, the shared secret will be unavailable so the unique key cannot be calculated. The payload octet string may also be omitted in the presentation. The following instructions describe how to get the corresponding MAC of each payload:¶
The binary representation is created by appending data into a single octet string in the following order:¶
The Holder's Presentation Key MUST be included via the Holder Presentation Key header parameter.¶
The Holder's Presentation Algorithm MUST be included via the Holder Presentation Algorithm header parameter unless there is another way for the holder and verifier to unambiguously determine the appropriate algorithm to use.¶
The issuer proof consists of two octet strings.¶
The first octet string is the issuer signature over the combined MAC representation. The issuer signs the combined MAC representation using its stable public key, and the internal signing algorithm for the given fully-specified MAC algorithm variant.¶
The second octet string is the Shared Secret used to generate the per-payload keys for the combined representation.¶
See the Presentation Protected Header section given for Single Use algorithms.¶
The presentation proof is made of multiple components.¶
The first proof component is the issuer signature over the Combined MAC Representation, which is provided as the first proof component from the issued form.¶
There will now be one proof component per payload slot in the issued JWP. These are used by the verifier to reconstruct the combined MAC representation without access to the Shared Secret. The proof components are calculated per the instructions used to generate the Combined MAC Representation¶
If a payload is disclosed, the corresponding proof component will be the unique key.¶
If a payload is not disclosed, the corresponding proof component will be the payload's MAC (using the unique key.)¶
The holder protected header, issuer protected header, payload slots (distinguishing which are being disclosed) and above proof components are inputs to determine the presentation internal representation.¶
The holder's signature over the presentation internal representation (using the holder's private key and the holder presentation algorithm) is then included as one additional proof component in the final presentation.¶
The presented form should have two more proof components than payload slots in the issued JWP.¶
Note that the second component of the issued JWP is a shared secret for use by the holder to generate the unique keys used in the Combined MAC Representation. This MUST NOT be included in the presentation.¶
Verification is performed using the following steps.¶
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¶
Editor's Note: This will follow once the algorithms defined here have become more stable.¶
The following registration procedure is used for all the registries established by this specification.¶
Values are registered on a Specification Required [RFC5226] basis after a three-week review period on the jose-reg-review@ietf.org mailing list, on the advice of one or more Designated Experts. However, to allow for the allocation of values prior to publication, the Designated Experts may approve registration once they are satisfied that such a specification will be published.¶
Registration requests sent to the mailing list for review should use an appropriate subject (e.g., "Request to register JWP algorithm: example").¶
Within the review period, the Designated Experts will either approve or deny the registration request, communicating this decision to the review list and IANA. Denials should include an explanation and, if applicable, suggestions as to how to make the request successful. Registration requests that are undetermined for a period longer than 21 days can be brought to the IESG's attention (using the iesg@ietf.org mailing list) for resolution.¶
Criteria that should be applied by the Designated Experts include determining whether the proposed registration duplicates existing functionality, whether it is likely to be of general applicability or useful only for a single application, and whether the registration description is clear.¶
IANA must only accept registry updates from the Designated Experts and should direct all requests for registration to the review mailing list.¶
It is suggested that multiple Designated Experts be appointed who are able to represent the perspectives of different applications using this specification, in order to enable broadly informed review of registration decisions. In cases where a registration decision could be perceived as creating a conflict of interest for a particular Expert, that Expert should defer to the judgment of the other Experts.¶
This specification establishes the IANA "JSON Web Proof Algorithms"
registry for values of the JWP alg (algorithm) parameter in JWP Header
Parameters. The registry records the algorithm name, the algorithm
description, the algorithm usage locations, the implementation
requirements, the change controller, and a reference to the
specification that defines it. The same algorithm name can be
registered multiple times, provided that the sets of usage locations are
disjoint.¶
It is suggested that the length of the key be included in the algorithm name when multiple variations of algorithms are being registered that use keys of different lengths and the key lengths for each need to be fixed (for instance, because they will be created by key derivation functions). This allows readers of the JSON text to more easily make security decisions.¶
The Designated Experts should perform reasonable due diligence that algorithms being registered either are currently considered cryptographically credible or are being registered as Deprecated or Prohibited.¶
The implementation requirements of an algorithm may be changed over time as the cryptographic landscape evolves, for instance, to change the status of an algorithm to Deprecated or to change the status of an algorithm from Optional to Recommended+ or Required. Changes of implementation requirements are only permitted on a Specification Required basis after review by the Designated Experts, with the new specification defining the revised implementation requirements level.¶
Single-Use JWP using ES256.)
Descriptive names may not match other registered names unless the
Designated Experts state that there is a compelling reason to
allow an exception.¶
SU-ES256). This label is a
case-sensitive ASCII string. JSON Labels may not match other
registered labels in a case-insensitive manner unless the
Designated Experts state that there is a compelling reason to allow
an exception.¶
1). CBOR Labels may not match
other registered labels unless the Designated Experts state that there
is a compelling reason to allow an exception.¶
Issued or Presented. Other values may be used with the
approval of a Designated Expert.¶
Required, Recommended, Optional, Deprecated, or
Prohibited. Optionally, the word can be followed by a + or -.
The use of + indicates that the requirement strength is likely to be
increased in a future version of the specification. The use of -
indicates that the requirement strength is likely to be decreased in a
future version of the specification. Any identifiers registered for
algorithms that are otherwise unsuitable for direct use as JWP
algorithms must be registered as Prohibited.¶
SU-ES256¶
SU-ES384¶
SU-ES512¶
BBS¶
BBS_BLS12381G1_XMD:SHA-256_SSWU_RO_H2G_HM2S_¶
MAC-H256¶
MAC-H256 uses HMAC SHA-256 as the MAC, and
ECDSA using P-256 and SHA-256 for the signatures¶
MAC-H384¶
MAC-H384 uses HMAC SHA-384 as the MAC, and
ECDSA using P-384 and SHA-384 for the signatures¶
MAC-H512¶
MAC-H512 uses HMAC SHA-512 as the MAC, and
ECDSA using P-521 and SHA-512 for the signatures¶
MAC-K25519¶
MAC-K25519 uses KMAC SHAKE128 as the MAC,
and EdDSA using Curve25519 for the signatures¶
MAC-K448¶
MAC-K448 uses KMAC SHAKE256 as the MAC, and
EdDSA using Curve448 for the signatures¶
MAC-H256K¶
MAC-H256K uses HMAC SHA-256 as the MAC, and
ECDSA using secp256k1 and SHA-256 for the signatures¶
The following examples use algorithms defined in JSON Proof Algorithms and also contain the keys used, so that implementations can validate these samples.¶
This example uses the Single-Use Algorithm as defined in JSON Proof Algorithms to create a JSON Proof Token. It demonstrates how to apply selective disclosure using an array of traditional JWS-based signatures. Unlinkability is only achieved by using each JWP one time, as multiple uses are inherently linkable via the traditional ECDSA signature embedded in the proof.¶
To begin, we need two asymmetric keys for Single Use: one that represents the JPT Issuer's stable key and the other is an ephemeral key generated by the Issuer just for this JWP.¶
This is the Issuer's stable private key used in this example in the JWK format:¶
{
"kty": "EC",
"crv": "P-256",
"x": "i_Z_bPAFjYkauFJGwP0Bb9M_US7C5CAKlCy88he-xSI",
"y": "RcFnvnmnLK2sfo280NOaEtevRgYUquBOAAEp7s98Z0E",
"d": "cdSyxqimC7atqvhLnQ6x1079YGsZAECaDGpEtboyzyI"
}
This is the ephemeral private key used in this example in the JWK format:¶
{
"kty": "EC",
"crv": "P-256",
"x": "CKivX6GiDIO_0-HjzkYzWWFo1Sx_5arYEQ-u_cM876M",
"y": "C69M7i1nZMlvz79_8TYd135gJZqzzj4bEakQ8ucIvJ8",
"d": "X2KGIA4by9ygXFY2fZVsPh9kxSKqXtRgxW0wAoqoSxc"
}
This is the Holder's presentation private key used in this example in the JWK format:¶
{
"kty": "EC",
"crv": "P-256",
"x": "fMapiWuP_wGUQskk9sCPMEnbiMmhNeifVEw6bi3NktM",
"y": "DbEB2WcEz6Q81RDFLNNc340ZhAIV5sQk-sUnBkAbgxs",
"d": "c5usJjaUt_cTCCXok78MH2n1mgPwT1JM633lEpTfAfU"
}
The JWP Protected Header declares that the data structure is a JPT and the JWP Proof Input is secured using the Single-Use ECDSA algorithm with the P-256 curve and SHA-256 digest. It also includes the ephemeral public key, the Holder's presentation public key and list of claims used for this JPT.¶
{
"alg": "SU-ES256",
"typ": "JPT",
"iss": "https://issuer.example",
"hpa": "ES256",
"claims": [
"iat",
"exp",
"family_name",
"given_name",
"email",
"address",
"age_over_21"
],
"iek": {
"kty": "EC",
"crv": "P-256",
"x": "CKivX6GiDIO_0-HjzkYzWWFo1Sx_5arYEQ-u_cM876M",
"y": "C69M7i1nZMlvz79_8TYd135gJZqzzj4bEakQ8ucIvJ8"
},
"hpk": {
"kty": "EC",
"crv": "P-256",
"x": "fMapiWuP_wGUQskk9sCPMEnbiMmhNeifVEw6bi3NktM",
"y": "DbEB2WcEz6Q81RDFLNNc340ZhAIV5sQk-sUnBkAbgxs"
}
}
eyJhbGciOiJTVS1FUzI1NiIsInR5cCI6IkpQVCIsImlzcyI6Imh0dHBzOi8vaXNzdWVyL mV4YW1wbGUiLCJocGEiOiJFUzI1NiIsImNsYWltcyI6WyJpYXQiLCJleHAiLCJmYW1pbH lfbmFtZSIsImdpdmVuX25hbWUiLCJlbWFpbCIsImFkZHJlc3MiLCJhZ2Vfb3Zlcl8yMSJ dLCJpZWsiOnsia3R5IjoiRUMiLCJjcnYiOiJQLTI1NiIsIngiOiJDS2l2WDZHaURJT18w LUhqemtZeldXRm8xU3hfNWFyWUVRLXVfY004NzZNIiwieSI6IkM2OU03aTFuWk1sdno3O V84VFlkMTM1Z0pacXp6ajRiRWFrUTh1Y0l2SjgifSwiaHBrIjp7Imt0eSI6IkVDIiwiY3 J2IjoiUC0yNTYiLCJ4IjoiZk1hcGlXdVBfd0dVUXNrazlzQ1BNRW5iaU1taE5laWZWRXc 2YmkzTmt0TSIsInkiOiJEYkVCMldjRXo2UTgxUkRGTE5OYzM0MFpoQUlWNXNRay1zVW5C a0FiZ3hzIn19
The Single Use algorithm utilizes multiple individual JWS Signatures.
Each signature value is generated by creating a JWS with a single
Protected Header with the associated alg value. In this example, the
fixed header used for each JWS is the serialized JSON Object
{"alg":"ES256"}. This protected header will be used to generate a
signature over each corresponding payload in the JWP. The corresponding
octet value in the proof is the octet string (base64url-decoded) value
of the signature.¶
The final proof value from the Issuer is an array with the octets of the header signature, followed by entries for each payload signature.¶
[
1714521600,
1717199999,
"Doe",
"Jay",
"jaydoe@example.org",
{
"formatted": "1234 Main St.\nAnytown, CA 12345\nUSA",
"street_address": "1234 Main St.",
"locality": "Anytown",
"region": "CA",
"postal_code": 12345,
"country": "USA"
},
true
]
The compact serialization of the same JPT is:¶
eyJhbGciOiJTVS1FUzI1NiIsInR5cCI6IkpQVCIsImlzcyI6Imh0dHBzOi8vaXNzdWVyL mV4YW1wbGUiLCJocGEiOiJFUzI1NiIsImNsYWltcyI6WyJpYXQiLCJleHAiLCJmYW1pbH lfbmFtZSIsImdpdmVuX25hbWUiLCJlbWFpbCIsImFkZHJlc3MiLCJhZ2Vfb3Zlcl8yMSJ dLCJpZWsiOnsia3R5IjoiRUMiLCJjcnYiOiJQLTI1NiIsIngiOiJDS2l2WDZHaURJT18w LUhqemtZeldXRm8xU3hfNWFyWUVRLXVfY004NzZNIiwieSI6IkM2OU03aTFuWk1sdno3O V84VFlkMTM1Z0pacXp6ajRiRWFrUTh1Y0l2SjgifSwiaHBrIjp7Imt0eSI6IkVDIiwiY3 J2IjoiUC0yNTYiLCJ4IjoiZk1hcGlXdVBfd0dVUXNrazlzQ1BNRW5iaU1taE5laWZWRXc 2YmkzTmt0TSIsInkiOiJEYkVCMldjRXo2UTgxUkRGTE5OYzM0MFpoQUlWNXNRay1zVW5C a0FiZ3hzIn19.MTcxNDUyMTYwMA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheSI~ImpheWRvZU BleGFtcGxlLm9yZyI~eyJmb3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5Bbnl0b3duLCB DQSAxMjM0NVxuVVNBIiwic3RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4gU3QuIiwibG9j YWxpdHkiOiJBbnl0b3duIiwicmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZSI6MTIzNDUsI mNvdW50cnkiOiJVU0EifQ~dHJ1ZQ.5So1vOnOGzQhDXPzKkjoKry_8NKa2uzE3mW3RkWY gqlFVd3LXuE0-gZq-ggAA4onMeeEYyGLMlxDHvC1FV34PQ~3vo7JZmo84pdGN8f0BZ3T4 Ms6E1hhCV2PlZz93kkpqFboWLdFVEBxTDeRJ8PLp6HjPKLgKFELVZDh859erE0Uw~ECKc jaLqdrZraYmfsZmIzCuxGg_wSEnyTWcDi2FcTn__ABln8-5Z2Sg1dzfGnH64C23mfYc7Q 46saS2XT3e1AQ~mY_PFjDeRIGxYUWmYqQIMHsUkWS6oU0XbxjrwNzekNLeGuR-AJknM-u D2P3809Qp28avEazLwmpTWTE6SJRUyg~F-47-SU76eSz6X9O5sJCJZ9uO6Lh6Kvz8btxK azIm8JSrO6egicBN0yqSAbfPYHy22o3aA8eUX664ErvmDsBqQ~_nMiJH5MSI5kuuth5Dz EFonBVzrOrVGSGwucXO5t2vR6Ejtnf4BC0lk6EsIe4kt5K8saRfrlv1h80sWRHfPiMg~h O2V1MWUl_o1kS95wxzRp30YsEqHq9QX5GTh973Y4ktK2FWyiqqNQomtT-iLt0jre2H2Vj CFu3ikNH0QAEaQmg~rN3FbRRDRsumiE768TZ36rTOe_ZCFZl0QPUqTumj82kmxW4piGGc FyduwUx442YLfebwQGvriIe_Q-X5Ozl2ew
To present this JPT, we first use the following presentation header with a nonce (provided by the Verifier):¶
{
"alg": "SU-ES256",
"aud": "https://recipient.example.com",
"nonce": "bVvMg_5vEl_GKU345obR3Wgfgg3j3_NNYJO9J5PxEGw"
}
eyJhbGciOiJTVS1FUzI1NiIsImF1ZCI6Imh0dHBzOi8vcmVjaXBpZW50LmV4YW1wbGUuY 29tIiwibm9uY2UiOiJiVnZNZ181dkVsX0dLVTM0NW9iUjNXZ2ZnZzNqM19OTllKTzlKNV B4RUd3In0
We apply selective disclosure of only the given name and age claims (family name and email hidden), and remove the proof components corresponding to these entries.¶
Using the selectively disclosed information, we generate the presentation internal representation. Using that and the selectively disclosed payloads, we get the following presented JPT in compact serialization:¶
eyJhbGciOiJTVS1FUzI1NiIsImF1ZCI6Imh0dHBzOi8vcmVjaXBpZW50LmV4YW1wbGUuY 29tIiwibm9uY2UiOiJiVnZNZ181dkVsX0dLVTM0NW9iUjNXZ2ZnZzNqM19OTllKTzlKNV B4RUd3In0.eyJhbGciOiJTVS1FUzI1NiIsInR5cCI6IkpQVCIsImlzcyI6Imh0dHBzOi8 vaXNzdWVyLmV4YW1wbGUiLCJocGEiOiJFUzI1NiIsImNsYWltcyI6WyJpYXQiLCJleHAi LCJmYW1pbHlfbmFtZSIsImdpdmVuX25hbWUiLCJlbWFpbCIsImFkZHJlc3MiLCJhZ2Vfb 3Zlcl8yMSJdLCJpZWsiOnsia3R5IjoiRUMiLCJjcnYiOiJQLTI1NiIsIngiOiJDS2l2WD ZHaURJT18wLUhqemtZeldXRm8xU3hfNWFyWUVRLXVfY004NzZNIiwieSI6IkM2OU03aTF uWk1sdno3OV84VFlkMTM1Z0pacXp6ajRiRWFrUTh1Y0l2SjgifSwiaHBrIjp7Imt0eSI6 IkVDIiwiY3J2IjoiUC0yNTYiLCJ4IjoiZk1hcGlXdVBfd0dVUXNrazlzQ1BNRW5iaU1ta E5laWZWRXc2YmkzTmt0TSIsInkiOiJEYkVCMldjRXo2UTgxUkRGTE5OYzM0MFpoQUlWNX NRay1zVW5Ca0FiZ3hzIn19.MTcxNDUyMTYwMA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheSI~ ImpheWRvZUBleGFtcGxlLm9yZyI~eyJmb3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5Bb nl0b3duLCBDQSAxMjM0NVxuVVNBIiwic3RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4gU3 QuIiwibG9jYWxpdHkiOiJBbnl0b3duIiwicmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZSI 6MTIzNDUsImNvdW50cnkiOiJVU0EifQ~dHJ1ZQ~~.5So1vOnOGzQhDXPzKkjoKry_8NKa 2uzE3mW3RkWYgqlFVd3LXuE0-gZq-ggAA4onMeeEYyGLMlxDHvC1FV34PQ~3vo7JZmo84 pdGN8f0BZ3T4Ms6E1hhCV2PlZz93kkpqFboWLdFVEBxTDeRJ8PLp6HjPKLgKFELVZDh85 9erE0Uw~ECKcjaLqdrZraYmfsZmIzCuxGg_wSEnyTWcDi2FcTn__ABln8-5Z2Sg1dzfGn H64C23mfYc7Q46saS2XT3e1AQ~mY_PFjDeRIGxYUWmYqQIMHsUkWS6oU0XbxjrwNzekNL eGuR-AJknM-uD2P3809Qp28avEazLwmpTWTE6SJRUyg~F-47-SU76eSz6X9O5sJCJZ9uO 6Lh6Kvz8btxKazIm8JSrO6egicBN0yqSAbfPYHy22o3aA8eUX664ErvmDsBqQ~_nMiJH5 MSI5kuuth5DzEFonBVzrOrVGSGwucXO5t2vR6Ejtnf4BC0lk6EsIe4kt5K8saRfrlv1h8 0sWRHfPiMg~7Qp-BMzKAbf9Y-OQsw-JFKUg3dmO6omyX6Z9w9ApJlUpqn9uNlT__fhFuc a9W-7HYGtxb3AngiUht-Y0F0pVAQ¶
Figure: Presentation (SU-ES256, JSON, Compact Serialization)¶
This example is meant to mirror the prior compact serialization, using RFC8392 and claims from [I-D.maldant-spice-oidc-cwt], illustrated using [I-D.ietf-cbor-edn-literals] (EDN).¶
To simplify this example, the same information is represented as the JPT example above, including the same public and private keys.¶
{ / protected header /
1: 1, / alg: "SU-ES256" /
3: 20, / typ: "JPT" (20CPA) /
5: "https://issuer.example", / iss: "https://issuer.example" /
6: [ / claims /
6, / "iat" /
4, / "exp" /
170, / "family_name" (I-D.maldant-spice-oidc-cwt TBD1) /
171, / "given_name" (I-D.maldant-spice-oidc-cwt TBD2) /
179, / "email" (I-D.maldant-spice-oidc-cwt TBD10) /
187, / "address" (I-D.maldant-spice-oidc-cwt TBD18) /
"age_over_21"
],
8: { / iek /
1: 2, / kty : "EC2" /
-1: 1, / crv: "P-256" /
-2: h'08a8af5fa1a20c83bfd3e1e3ce4633596168d52c7fe5aad8110faefd' +
h'c33cefa3', / x /
-3: h'0baf4cee2d6764c96fcfbf7ff1361dd77e60259ab3ce3e1b11a910f2' +
h'e708bc9f' / y /
},
9: { / hpk /
1: 2, / kty: "EC2" /
-1: 1, / crv: "P-256" /
-2: h'7cc6a9896b8fff019442c924f6c08f3049db88c9a135e89f544c3a6e' +
h'2dcd92d3', / x /
-3: h'0db101d96704cfa43cd510c52cd35cdf8d19840215e6c424fac52706' +
h'401b831b' / y /
},
10: -9 / hpa: "ESP256" (I-D.ietf-jose-fully-specified-algorithms TBD-9) /
}
¶
Figure: Issuer Protected Header (SU-ES256, CBOR)¶
[ / payloads /
/ iat / 171452160,
/ exp / 171719999,
/ family_name / "Doe",
/ given_name / "Jay",
/ email / "jaydoe@example.org",
/ address / {
/ formatted / 1: "1234 Main St.\nAnytown, CA 12345\nUSA",
/ street / 2: "1234 Main St.",
/ locality / 3: "Anytown",
/ region / 4: "CA",
/ post code / 5: "90210",
/ country / 6: "USA"
},
/ age_over_21 / true
]
¶
Figure: Issuer Payloads (as CBOR array)¶
When signed and serialized, the CPT is represented by the following CBOR (in hex):¶
8358cfa701010314057668747470733a2f2f6973737565722e6578616d706c65 0687060418aa18ab18b318bb6b6167655f6f7665725f323108a4010220012158 2008a8af5fa1a20c83bfd3e1e3ce4633596168d52c7fe5aad8110faefdc33cef a32258200baf4cee2d6764c96fcfbf7ff1361dd77e60259ab3ce3e1b11a910f2 e708bc9f09a4010220012158207cc6a9896b8fff019442c924f6c08f3049db88 c9a135e89f544c3a6e2dcd92d32258200db101d96704cfa43cd510c52cd35cdf 8d19840215e6c424fac52706401b831b0a28871a0a3827001a0a3c3d3f63446f 65634a6179726a6179646f65406578616d706c652e6f7267a601782331323334 204d61696e2053742e0a416e79746f776e2c2043412031323334350a55534102 6d31323334204d61696e2053742e0367416e79746f776e046243410565393032 31300663555341f5885840d2f1316a70cae3a879c3893b2a8475318850969593 df79a0b2f01c3c0fd076d7b5c2107daa1ee20b5db4c271647ffe65570687d6bc 7fea0f5ecb6c9689cb16ba58406384c5c3b1c09fa19cd0f885310b3b476cfd7e 496f32cd16495ff6962c10f8fa48bdeac1fdc3d97deb52719afbb94d0b606010 3f5c78fe8edbfd8e588d36b2fa58406d8a51d17f5d2ccdd96af1fff2c4477661 7d82aed3428d0b92d46c970e715a4fdf27e56489e48d5ee7c09529b6d82ca4d4 b3a0f12b0f466acfceb0bbaa7ba6ff5840b527c7b41fe4c477f8fe5705228740 3fb1b2bfe80e5fdc6c4f02c0ada98c26a228d7182bed3eef0aba7cd4e42bf740 ec35b974ee7f3ec46deb2d3ed71f1e08fe58400a37ea1801449031851f79ffbf 0a89d9869473dd79b3b4fa4ece373d8b6f09074b4ffc08dd8d01bd08d469fca3 f36fcb8805029487a5b73d76634339e415d8b458405105e9f8e3c429913013b3 25717cc0ce40653f3fb87385b5c9c9911906e146a4061f3863b718215dc2ccb4 2cc5ec9366545f683f86071405223a62bf0b4d65af5840b5608335b3b7d2d7c3 acee8ac758a36e9c77b1930b43e96fa535f7966eb8272026ef56d560dea473f1 cb222c2e9c18713aa4a6267272f1179e42c27fe7a1d3cf5840f315ca27758d18 aef220336d3682c62d2de409a58cd5f6e8d1247b51e8963deba2b491ee28aaca f30ba15697e3984534e067035ab86099617bcfff93930c976b¶
Fixtures: Issued Form (SU-ES256, CBOR)¶
The presented form, similarly to the issued form above, is made with the holder conveying the same parameters and the same set of selectively disclosed payloads as the JPT above:¶
{ / protected header /
1: 1, / alg: "SU-ES256" /
6: "https://recipient.example.com", / aud /
7: h'6d5bcc83fe6f125fc6294df8e686d1dd681f820de3dff34d6093bd2793f1106c', / nonce /
}
¶
Figure: Holder Protected Header (SU-ES256, CBOR)¶
When the appropriate proof is generated, the CPT is serialized into the following CBOR (in hex):¶
845846a3010106781d68747470733a2f2f726563697069656e742e6578616d70 6c652e636f6d0758206d5bcc83fe6f125fc6294df8e686d1dd681f820de3dff3 4d6093bd2793f1106c58cfa701010314057668747470733a2f2f697373756572 2e6578616d706c650687060418aa18ab18b318bb6b6167655f6f7665725f3231 08a40102200121582008a8af5fa1a20c83bfd3e1e3ce4633596168d52c7fe5aa d8110faefdc33cefa32258200baf4cee2d6764c96fcfbf7ff1361dd77e60259a b3ce3e1b11a910f2e708bc9f09a4010220012158207cc6a9896b8fff019442c9 24f6c08f3049db88c9a135e89f544c3a6e2dcd92d32258200db101d96704cfa4 3cd510c52cd35cdf8d19840215e6c424fac52706401b831b0a28891a0a382700 1a0a3c3d3f63446f65634a6179726a6179646f65406578616d706c652e6f7267 a601782331323334204d61696e2053742e0a416e79746f776e2c204341203132 3334350a555341026d31323334204d61696e2053742e0367416e79746f776e04 624341056539303231300663555341f5f6f6875840d2f1316a70cae3a879c389 3b2a8475318850969593df79a0b2f01c3c0fd076d7b5c2107daa1ee20b5db4c2 71647ffe65570687d6bc7fea0f5ecb6c9689cb16ba58406384c5c3b1c09fa19c d0f885310b3b476cfd7e496f32cd16495ff6962c10f8fa48bdeac1fdc3d97deb 52719afbb94d0b6060103f5c78fe8edbfd8e588d36b2fa58406d8a51d17f5d2c cdd96af1fff2c44776617d82aed3428d0b92d46c970e715a4fdf27e56489e48d 5ee7c09529b6d82ca4d4b3a0f12b0f466acfceb0bbaa7ba6ff5840b527c7b41f e4c477f8fe57052287403fb1b2bfe80e5fdc6c4f02c0ada98c26a228d7182bed 3eef0aba7cd4e42bf740ec35b974ee7f3ec46deb2d3ed71f1e08fe58400a37ea 1801449031851f79ffbf0a89d9869473dd79b3b4fa4ece373d8b6f09074b4ffc 08dd8d01bd08d469fca3f36fcb8805029487a5b73d76634339e415d8b4584051 05e9f8e3c429913013b325717cc0ce40653f3fb87385b5c9c9911906e146a406 1f3863b718215dc2ccb42cc5ec9366545f683f86071405223a62bf0b4d65af58 40783ef8d76aa558e92d2b03675544e2b05a5ed3742624004005bf2d8f46ee6b 59cb45ac7df5b590b031eb71ebee37770e4ccd6c2683fb6434018deec8ed8284 73¶
Figure: Presented Form (SU-ES256, CBOR)¶
The following example uses the BBS algorithm.¶
This is the Issuer's stable private key in the JWK format:¶
{
"kty": "EC2",
"alg": "BBS",
"use": "proof",
"crv": "BLS12381G2",
"x": "Ebjzs56iPoHpYICaReq9jsfgsX2vHLURDWm5obuKgGPfdef8lRd6jnsp8-3Hc
_2CGILIyOR8-IaCXye2oBh3DTS6jkVZbc6NEayPXvuTX8KyaaWIEE7hAYx7zDK
KwaXK",
"y": "FDxnE7R0d7KkcIj1ucdlSmBgUgNxLuOiljRkVrazfZay63solSjh4NskuXdoe
SGQETn2PyWqIC3Sq2wqEbhAzclKJcKbTAbDQpWphWIL0ETW9Q6v4hJBhKLMEo-
sQxJY",
"d": "V9mNLf_HHz5QAH-SMUK0ZT13pQKpMujOYSjFzMiV4vE"
}
There is no additional holder key necessary for presentation proofs.¶
For the following protected header and array of payloads:¶
{
"kid": "HjfcpyjuZQ-O8Ye2hQnNbT9RbbnrobptdnExR0DUjU8",
"alg": "BBS"
}
These components are signed using the private issuer key previously given, which is then representable in the following serialization:¶
eyJraWQiOiJIamZjcHlqdVpRLU84WWUyaFFuTmJUOVJiYm5yb2JwdGRuRXhSMERValU4I iwiYWxnIjoiQkJTIn0.MTcxNDUyMTYwMA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheSI~Imph eWRvZUBleGFtcGxlLm9yZyI~eyJmb3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5Bbnl0b 3duLCBDQSAxMjM0NVxuVVNBIiwic3RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4gU3QuIi wibG9jYWxpdHkiOiJBbnl0b3duIiwicmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZSI6MTI zNDUsImNvdW50cnkiOiJVU0EifQ~dHJ1ZQ.pPSk9HrEnPzUDCyPteSh0-Nqsc77SDPQpn BuFdVIaM1bhk_FyzrMJys-TBf6efGvJCjQA-96RgRu_5cxfN7x5QjAjIr3tILMLFjSQnk XYvE
For a presentation with the following presentation header:¶
{
"alg": "BBS",
"aud": "https://recipient.example.com",
"nonce": "wrmBRkKtXjQ"
}
The holder decides to share all information other than the email address, and generates a proof. That proof is represented in the following serialization:¶
eyJhbGciOiJCQlMiLCJhdWQiOiJodHRwczovL3JlY2lwaWVudC5leGFtcGxlLmNvbSIsI m5vbmNlIjoid3JtQlJrS3RYalEifQ.eyJraWQiOiJIamZjcHlqdVpRLU84WWUyaFFuTmJ UOVJiYm5yb2JwdGRuRXhSMERValU4IiwiYWxnIjoiQkJTIn0.MTcxNDUyMTYwMA~MTcxN zE5OTk5OQ~IkRvZSI~IkpheSI~~~.k1juNOlQ1D6ZLyjtDJCqVPRSHnquxFuuw_IIqBqc danXeGxV_6esg8x9wdxxaQ0pgsUL2uJ4twFyYK3h2NKVabABtKLNlQmCj213pWOFrh7BT id92bSrFBctpkNqdoA-oJ6j504v8zc2keymQ9DOlm9tOqe-kHFn_jRMyXXwSsRgXguCys VsxaD3Rf_nUd5kaeYjX3FljehIir04R59DDP8h9TMmU1_QqzguI3sbULQNlXpqmtDhu9H v8SwQ-ZOJr-ohhPoo8oAkDmZaQy3L9RVXuKUaRQllpGsUAAPzSJtJC4nWn2xrwfhQx6GW CHTDAQ41IY9djk3KnC5rYu433QVHAK33SkyxGjA5W17mtmFPn5bv-F5UNOVjDOjB1Q5gE s-oHc6sdCNc-N5kL8jG5hUaML5ABN-4qPOtGb50LCpobG6ITuGgmeBpy7CQbMXNFS6uul qWykAEnDMWxH4z-wwdOyaANRp6n38x9CvmIcQ
The following example uses the MAC-H256 algorithm.¶
This is the Issuer's stable private key in the JWK format:¶
{
"kty": "EC",
"crv": "P-256",
"x": "i_Z_bPAFjYkauFJGwP0Bb9M_US7C5CAKlCy88he-xSI",
"y": "RcFnvnmnLK2sfo280NOaEtevRgYUquBOAAEp7s98Z0E",
"d": "cdSyxqimC7atqvhLnQ6x1079YGsZAECaDGpEtboyzyI"
}
This is the Issuer's ephemerally generated shared secret:¶
"Fah_M2ITxKU7OQtWIi5BJ7D-MBKoXfNHZt4NkJ0oP4s"
This is the Holder's presentation private key in the JWK format:¶
{
"kty": "EC",
"crv": "P-256",
"x": "fMapiWuP_wGUQskk9sCPMEnbiMmhNeifVEw6bi3NktM",
"y": "DbEB2WcEz6Q81RDFLNNc340ZhAIV5sQk-sUnBkAbgxs",
"d": "c5usJjaUt_cTCCXok78MH2n1mgPwT1JM633lEpTfAfU"
}
For the following protected header and array of payloads:¶
{
"alg": "MAC-H256",
"hpa": "ES256",
"typ": "JPT",
"iss": "https://issuer.example",
"claims": [
"iat",
"exp",
"family_name",
"given_name",
"email",
"address",
"age_over_21"
],
"hpk": {
"kty": "EC",
"crv": "P-256",
"use": "sign",
"x": "fMapiWuP_wGUQskk9sCPMEnbiMmhNeifVEw6bi3NktM",
"y": "DbEB2WcEz6Q81RDFLNNc340ZhAIV5sQk-sUnBkAbgxs"
}
}
[
1714521600,
1717199999,
"Doe",
"Jay",
"jaydoe@example.org",
{
"formatted": "1234 Main St.\nAnytown, CA 12345\nUSA",
"street_address": "1234 Main St.",
"locality": "Anytown",
"region": "CA",
"postal_code": 12345,
"country": "USA"
},
true
]
The issuer generates an array of derived keys, one per payload slot. This is done using the shared secret as the key and a binary value based on the payload slot index (from zero) as input to the HMAC operation.¶
This results in the following set of derived keys:¶
[ "lvO41mMxvYm3zMWbDSnWghyDgtphlhgPxTQlGXp1YYs", "cts-d-IcCleOTda2V7c5g0wieDHbwwv4AGOyZNVGdRg", "A2XMeWkqh1IDhbxUh-FZX4kngDzAr60_p1EGICSB6Ts", "DjMjv2Gv2m-JfHmxlnMgoa7409GhiM8JJPgSOwtctsY", "wZEIKYh-wfC2QS7b73QWG0sHS8xq-zzvlVpMxvK1sWI", "p-yR_YCabGkOioNnFxW9Vpzw0Gpz6sbxS11EknXYKJ8", "h1FBETU6-med1WMKKD6UuoCi6XqGXdCqNhKn1M5p-xM" ]
A MAC is generated for each payload using the corresponding derived payload key. This results in the following set of MAC values:¶
[ "7YLK3cpNdV5L8ILKAYHs562x9oABf30zN8oKwoLfdTo", "2THyd9jb-yBLWD83fYz7jBTKOSc03IiQZVs8ObdRGmA", "E8ulQRSP40mkXIJlbHCpwPdrJdTsBt7b_wszsy33E2A", "3RdGcoasyVyZ4aoRareigdyXr56PH2Zg02vozH3AX_Q", "ThIuQhkOMeZ2FhiiZm7JqPJxc8cOge34zBy3ta9bVvM", "YT9cV98N0myHrAWNIOFloBbOiAuJ7GobD8zoKw_7hWU", "plRCwW1zinl5idP4N0RW6uJwFEtTIlZVhULPyCE_HAY" ]
The issuer protected header and payload MAC values are combined into a binary representation known as the Compact MAC Representation. This representation is signed with the issuer's private key.¶
The proof consists of two octet string values: the signature over the combined MAC representation, and the shared secret.¶
[ "5TADzZs07jGnXPmh3vp9k_c3sAlqvVfE19TV64R1ODpCkTDLEl-hGeb9ljeZEwGKMC njafwrb8c1fr_jpS1OmA", "AABznJvfOGhZNEH_zy8KWPObCPX8p8DAg-c3g9EhvyY" ]
The final issued JWP in compact serialization is:¶
eyJhbGciOiJNQUMtSDI1NiIsImhwYSI6IkVTMjU2IiwidHlwIjoiSlBUIiwiaXNzIjoia HR0cHM6Ly9pc3N1ZXIuZXhhbXBsZSIsImNsYWltcyI6WyJpYXQiLCJleHAiLCJmYW1pbH lfbmFtZSIsImdpdmVuX25hbWUiLCJlbWFpbCIsImFkZHJlc3MiLCJhZ2Vfb3Zlcl8yMSJ dLCJocGsiOnsia3R5IjoiRUMiLCJjcnYiOiJQLTI1NiIsInVzZSI6InNpZ24iLCJ4Ijoi Zk1hcGlXdVBfd0dVUXNrazlzQ1BNRW5iaU1taE5laWZWRXc2YmkzTmt0TSIsInkiOiJEY kVCMldjRXo2UTgxUkRGTE5OYzM0MFpoQUlWNXNRay1zVW5Ca0FiZ3hzIn19.MTcxNDUyM TYwMA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheSI~ImpheWRvZUBleGFtcGxlLm9yZyI~eyJm b3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5Bbnl0b3duLCBDQSAxMjM0NVxuVVNBIiwic 3RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4gU3QuIiwibG9jYWxpdHkiOiJBbnl0b3duIi wicmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZSI6MTIzNDUsImNvdW50cnkiOiJVU0EifQ~ dHJ1ZQ.5TADzZs07jGnXPmh3vp9k_c3sAlqvVfE19TV64R1ODpCkTDLEl-hGeb9ljeZEw GKMCnjafwrb8c1fr_jpS1OmA~AABznJvfOGhZNEH_zy8KWPObCPX8p8DAg-c3g9EhvyY
Next, we show the presentation of the JWP with selective disclosure.¶
For presentation with the following presentation protected header:¶
{
"alg": "MAC-H256",
"aud": "https://recipient.example.com",
"nonce": "bVvMg_5vEl_GKU345obR3Wgfgg3j3_NNYJO9J5PxEGw"
}
The holder will take the issuer proof (including shared secret) and derive the same individual payload MAC values (above).¶
In this case, the holder has decided not to disclose the last three
claims provided by the issuer (corresponding to email, address, and
age_over_21)¶
For each payload slot, the holder will provide one of two values as part of the proof value. For a disclosed payload, the holder will provide the corresponding derived key. For a non-disclosed payload, the holder will provide the corresponding MAC value.¶
The final presented proof value is an array of octet strings. The contents are presentation header signature, followed by the issuer signature, then the value disclosed by the holder for each payload. This results in the following proof:¶
[ "5TADzZs07jGnXPmh3vp9k_c3sAlqvVfE19TV64R1ODpCkTDLEl-hGeb9ljeZEwGKMC njafwrb8c1fr_jpS1OmA", "lvO41mMxvYm3zMWbDSnWghyDgtphlhgPxTQlGXp1YYs", "cts-d-IcCleOTda2V7c5g0wieDHbwwv4AGOyZNVGdRg", "A2XMeWkqh1IDhbxUh-FZX4kngDzAr60_p1EGICSB6Ts", "DjMjv2Gv2m-JfHmxlnMgoa7409GhiM8JJPgSOwtctsY", "ThIuQhkOMeZ2FhiiZm7JqPJxc8cOge34zBy3ta9bVvM", "YT9cV98N0myHrAWNIOFloBbOiAuJ7GobD8zoKw_7hWU", "plRCwW1zinl5idP4N0RW6uJwFEtTIlZVhULPyCE_HAY", "ZTe9cBk78H8MmcMkBK__8jAQ-bgEPYhZH0pYXyfyE8VFkInKxc1d3Cme4xrzz0_zP1 yl6I4tGEJV4uMohhrDDA" ]
The final presented JWP in compact serialization is:¶
eyJhbGciOiJNQUMtSDI1NiIsImF1ZCI6Imh0dHBzOi8vcmVjaXBpZW50LmV4YW1wbGUuY 29tIiwibm9uY2UiOiJiVnZNZ181dkVsX0dLVTM0NW9iUjNXZ2ZnZzNqM19OTllKTzlKNV B4RUd3In0.eyJhbGciOiJNQUMtSDI1NiIsImhwYSI6IkVTMjU2IiwidHlwIjoiSlBUIiw iaXNzIjoiaHR0cHM6Ly9pc3N1ZXIuZXhhbXBsZSIsImNsYWltcyI6WyJpYXQiLCJleHAi LCJmYW1pbHlfbmFtZSIsImdpdmVuX25hbWUiLCJlbWFpbCIsImFkZHJlc3MiLCJhZ2Vfb 3Zlcl8yMSJdLCJocGsiOnsia3R5IjoiRUMiLCJjcnYiOiJQLTI1NiIsInVzZSI6InNpZ2 4iLCJ4IjoiZk1hcGlXdVBfd0dVUXNrazlzQ1BNRW5iaU1taE5laWZWRXc2YmkzTmt0TSI sInkiOiJEYkVCMldjRXo2UTgxUkRGTE5OYzM0MFpoQUlWNXNRay1zVW5Ca0FiZ3hzIn19 .MTcxNDUyMTYwMA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheSI~~~.5TADzZs07jGnXPmh3vp 9k_c3sAlqvVfE19TV64R1ODpCkTDLEl-hGeb9ljeZEwGKMCnjafwrb8c1fr_jpS1OmA~l vO41mMxvYm3zMWbDSnWghyDgtphlhgPxTQlGXp1YYs~cts-d-IcCleOTda2V7c5g0wieD Hbwwv4AGOyZNVGdRg~A2XMeWkqh1IDhbxUh-FZX4kngDzAr60_p1EGICSB6Ts~DjMjv2G v2m-JfHmxlnMgoa7409GhiM8JJPgSOwtctsY~ThIuQhkOMeZ2FhiiZm7JqPJxc8cOge34 zBy3ta9bVvM~YT9cV98N0myHrAWNIOFloBbOiAuJ7GobD8zoKw_7hWU~plRCwW1zinl5i dP4N0RW6uJwFEtTIlZVhULPyCE_HAY~ZTe9cBk78H8MmcMkBK__8jAQ-bgEPYhZH0pYXy fyE8VFkInKxc1d3Cme4xrzz0_zP1yl6I4tGEJV4uMohhrDDA
This work was incubated in the DIF Applied Cryptography Working Group.¶
We would like to thank Alberto Solavagione for his valuable contributions to this specification.¶
The BBS examples were generated using the library at https://github.com/mattrglobal/pairing_crypto .¶
[[ To be removed from the final specification ]]¶
-10¶
-09¶
-08¶
-07¶
proof_key and presentation_key
names¶
proof_jwk to proof_key and presentation_jwk to
presentation_key to better represent that the key may be JSON or
CBOR-formatted.¶
proof_key and presentation_key to JWP where
they are defined. Consolidated usage, purpose, and requirements from
algorithm usage under these definitions.¶
BBS-PROOF into BBS¶
-06¶
presentation_header.¶
pjwk to presentation_jwk¶
-05¶
-04¶
BBS-DRAFT-5 to BBS, and from
BBS-PROOF-DRAFT-5 to BBS-PROOF¶
BBS_BLS12381G1_XMD:SHA-256_SSWU_RO_¶
-03¶
-02¶
BBS-DRAFT-3 and BBS-PROOF-DRAFT-3 algorithms based on
draft-irtf-cfrg-bbs-signatures-03.¶
BBS-X algorithm based on a particular implementation of
earlier drafts.¶
-01¶
issuer_header and presentation_header¶
-00¶