| 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": "a_H-BwPtMTftwSmvcm7IVc4SXVORAZI7-3s1sJadJJc",
"y": "CDrp08C0zI8Fnu2_02neoC4DCrDdhZWasbK-86luj08",
"d": "vewf1OM4w1lPXVc8FjfiDEUL-mRdabs1AhUWIcgTqRc"
}
This is the ephemeral private key used in this example in the JWK format:¶
{
"kty": "EC",
"crv": "P-256",
"x": "NEF-Td43WsKj2mVGfgfxQsqN9pa9ovf2RNc4PYLKqMM",
"y": "F66_na_oPnr8UX7TthiAJRaEnqo4wRRAXvk3XJTLOBQ",
"d": "bBUHpA5Bn127BdIX1bRvPbMHq8MYwNM72zPc6pUinQs"
}
This is the Holder's presentation private key used in this example in the JWK format:¶
{
"kty": "EC",
"crv": "P-256",
"x": "CIjnk8YTDI-nikYZf8T6z6Z5oA0imfqPHfxGUlWo580",
"y": "Dbs-DI1_0RKTVqwE9IZRiCfvLF5pVmsOIpo8x1wD-gY",
"d": "HbSTQhLXQ-UhSSrcINHmZyBFTYUm8jYVv96WRhQkFV4"
}
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": "NEF-Td43WsKj2mVGfgfxQsqN9pa9ovf2RNc4PYLKqMM",
"y": "F66_na_oPnr8UX7TthiAJRaEnqo4wRRAXvk3XJTLOBQ"
},
"hpk": {
"kty": "EC",
"crv": "P-256",
"x": "CIjnk8YTDI-nikYZf8T6z6Z5oA0imfqPHfxGUlWo580",
"y": "Dbs-DI1_0RKTVqwE9IZRiCfvLF5pVmsOIpo8x1wD-gY"
}
}
eyJhbGciOiJTVS1FUzI1NiIsInR5cCI6IkpQVCIsImlzcyI6Imh0dHBzOi8vaXNzdWVyL mV4YW1wbGUiLCJocGEiOiJFUzI1NiIsImNsYWltcyI6WyJpYXQiLCJleHAiLCJmYW1pbH lfbmFtZSIsImdpdmVuX25hbWUiLCJlbWFpbCIsImFkZHJlc3MiLCJhZ2Vfb3Zlcl8yMSJ dLCJpZWsiOnsia3R5IjoiRUMiLCJjcnYiOiJQLTI1NiIsIngiOiJORUYtVGQ0M1dzS2oy bVZHZmdmeFFzcU45cGE5b3ZmMlJOYzRQWUxLcU1NIiwieSI6IkY2Nl9uYV9vUG5yOFVYN 1R0aGlBSlJhRW5xbzR3UlJBWHZrM1hKVExPQlEifSwiaHBrIjp7Imt0eSI6IkVDIiwiY3 J2IjoiUC0yNTYiLCJ4IjoiQ0lqbms4WVRESS1uaWtZWmY4VDZ6Nlo1b0EwaW1mcVBIZnh HVWxXbzU4MCIsInkiOiJEYnMtREkxXzBSS1RWcXdFOUlaUmlDZnZMRjVwVm1zT0lwbzh4 MXdELWdZIn19
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 dLCJpZWsiOnsia3R5IjoiRUMiLCJjcnYiOiJQLTI1NiIsIngiOiJORUYtVGQ0M1dzS2oy bVZHZmdmeFFzcU45cGE5b3ZmMlJOYzRQWUxLcU1NIiwieSI6IkY2Nl9uYV9vUG5yOFVYN 1R0aGlBSlJhRW5xbzR3UlJBWHZrM1hKVExPQlEifSwiaHBrIjp7Imt0eSI6IkVDIiwiY3 J2IjoiUC0yNTYiLCJ4IjoiQ0lqbms4WVRESS1uaWtZWmY4VDZ6Nlo1b0EwaW1mcVBIZnh HVWxXbzU4MCIsInkiOiJEYnMtREkxXzBSS1RWcXdFOUlaUmlDZnZMRjVwVm1zT0lwbzh4 MXdELWdZIn19.MTcxNDUyMTYwMA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheSI~ImpheWRvZU BleGFtcGxlLm9yZyI~eyJmb3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5Bbnl0b3duLCB DQSAxMjM0NVxuVVNBIiwic3RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4gU3QuIiwibG9j YWxpdHkiOiJBbnl0b3duIiwicmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZSI6MTIzNDUsI mNvdW50cnkiOiJVU0EifQ~dHJ1ZQ.pxjdEgByvXszRLN8nNAzLkD9-23FpUcT9PC8GJJ1 xofOfkIMEftYmK-6UNhxXytVuLx_tBbSvrEOPG5oy1iYFg~FpdvS_bmS74VGnM1PM8VvS 7Y0WwxeHiNrg5VrkIwNn6A2NcWqMitKpcCZ7RGevmU3v9JJryh3LeayDbDVTuMvg~4BpH Kta_iV-nbs5P-hOK2-TUpZjbT8T__UO6TF-V5LBkPMGFdEiutREdi9xJBcxD3vEYm6Hjm 1oMUILf2XJ_yA~JWR6M8OpbvUUMEJxDbR2pGEs35uP9_ygOzWKD9w4_EhrpJad-pQYv7n BZ-gXf-VBIgN77XX6CcUI0ATJyrpf1Q~sv5CvfTvEW-irkDF0ljDG4La6Hx93H2JWPQaF p_zCbFsnA3ZptCfKjplz8vCzGbRpR_YrAU-s5bJVX21YnxucQ~prwqP59i6vWLHTYr2Or gZdGt9Ch0dwL8Mqj3aWdCgqdJDEyOlmXEAqlQt7NDqKAsrfYxoHBvIlAsCznM5QeJXQ~v rIpF6l8w9uc1IoLKeEZL0p5xrIcChsATKN5NgnVPb9fBV1aXr9On6uoE1Om3t0-uRG7ab yZKqWc0XwiGT8G2w~8123q99uFyMwPjkiqm_JjIwwYd2IxDQvR62crSq9QEi77wGqRXmW z5ZNDIbQ77oIVh-VhjifJsLcxCwbfaN-Lw
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": "nLK_RR7hryKlRfCZgGz9FQ4PZX_IbcL-SMtF30IJQz4"
}
eyJhbGciOiJTVS1FUzI1NiIsImF1ZCI6Imh0dHBzOi8vcmVjaXBpZW50LmV4YW1wbGUuY 29tIiwibm9uY2UiOiJuTEtfUlI3aHJ5S2xSZkNaZ0d6OUZRNFBaWF9JYmNMLVNNdEYzME lKUXo0In0
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 29tIiwibm9uY2UiOiJuTEtfUlI3aHJ5S2xSZkNaZ0d6OUZRNFBaWF9JYmNMLVNNdEYzME lKUXo0In0.eyJhbGciOiJTVS1FUzI1NiIsInR5cCI6IkpQVCIsImlzcyI6Imh0dHBzOi8 vaXNzdWVyLmV4YW1wbGUiLCJocGEiOiJFUzI1NiIsImNsYWltcyI6WyJpYXQiLCJleHAi LCJmYW1pbHlfbmFtZSIsImdpdmVuX25hbWUiLCJlbWFpbCIsImFkZHJlc3MiLCJhZ2Vfb 3Zlcl8yMSJdLCJpZWsiOnsia3R5IjoiRUMiLCJjcnYiOiJQLTI1NiIsIngiOiJORUYtVG Q0M1dzS2oybVZHZmdmeFFzcU45cGE5b3ZmMlJOYzRQWUxLcU1NIiwieSI6IkY2Nl9uYV9 vUG5yOFVYN1R0aGlBSlJhRW5xbzR3UlJBWHZrM1hKVExPQlEifSwiaHBrIjp7Imt0eSI6 IkVDIiwiY3J2IjoiUC0yNTYiLCJ4IjoiQ0lqbms4WVRESS1uaWtZWmY4VDZ6Nlo1b0Ewa W1mcVBIZnhHVWxXbzU4MCIsInkiOiJEYnMtREkxXzBSS1RWcXdFOUlaUmlDZnZMRjVwVm 1zT0lwbzh4MXdELWdZIn19.MTcxNDUyMTYwMA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheSI~ ImpheWRvZUBleGFtcGxlLm9yZyI~eyJmb3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5Bb nl0b3duLCBDQSAxMjM0NVxuVVNBIiwic3RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4gU3 QuIiwibG9jYWxpdHkiOiJBbnl0b3duIiwicmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZSI 6MTIzNDUsImNvdW50cnkiOiJVU0EifQ~dHJ1ZQ~~.pxjdEgByvXszRLN8nNAzLkD9-23F pUcT9PC8GJJ1xofOfkIMEftYmK-6UNhxXytVuLx_tBbSvrEOPG5oy1iYFg~FpdvS_bmS7 4VGnM1PM8VvS7Y0WwxeHiNrg5VrkIwNn6A2NcWqMitKpcCZ7RGevmU3v9JJryh3LeayDb DVTuMvg~4BpHKta_iV-nbs5P-hOK2-TUpZjbT8T__UO6TF-V5LBkPMGFdEiutREdi9xJB cxD3vEYm6Hjm1oMUILf2XJ_yA~JWR6M8OpbvUUMEJxDbR2pGEs35uP9_ygOzWKD9w4_Eh rpJad-pQYv7nBZ-gXf-VBIgN77XX6CcUI0ATJyrpf1Q~sv5CvfTvEW-irkDF0ljDG4La6 Hx93H2JWPQaFp_zCbFsnA3ZptCfKjplz8vCzGbRpR_YrAU-s5bJVX21YnxucQ~prwqP59 i6vWLHTYr2OrgZdGt9Ch0dwL8Mqj3aWdCgqdJDEyOlmXEAqlQt7NDqKAsrfYxoHBvIlAs CznM5QeJXQ~N0t2JT74-vL3U8D2RA-dH1n9t_N-kgrMEze0o98ukkmbAjAw0oEDe3Vr3z JgZRO_2XAuLlSiIuUplL_7nBwVDQ¶
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'34417e4dde375ac2a3da65467e07f142ca8df696bda2f7f644d7383d' +
h'82caa8c3', / x /
-3: h'17aebf9dafe83e7afc517ed3b618802516849eaa38c114405ef9375c' +
h'94cb3814' / y /
},
9: { / hpk /
1: 2, / kty: "EC2" /
-1: 1, / crv: "P-256" /
-2: h'0888e793c6130c8fa78a46197fc4facfa679a00d2299fa8f1dfc4652' +
h'55a8e7cd', / x /
-3: h'0dbb3e0c8d7fd1129356ac04f486518827ef2c5e69566b0e229a3cc7' +
h'5c03fa06' / 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 2034417e4dde375ac2a3da65467e07f142ca8df696bda2f7f644d7383d82caa8 c322582017aebf9dafe83e7afc517ed3b618802516849eaa38c114405ef9375c 94cb381409a4010220012158200888e793c6130c8fa78a46197fc4facfa679a0 0d2299fa8f1dfc465255a8e7cd2258200dbb3e0c8d7fd1129356ac04f4865188 27ef2c5e69566b0e229a3cc75c03fa060a28871a0a3827001a0a3c3d3f63446f 65634a6179726a6179646f65406578616d706c652e6f7267a601782331323334 204d61696e2053742e0a416e79746f776e2c2043412031323334350a55534102 6d31323334204d61696e2053742e0367416e79746f776e046243410565393032 31300663555341f5885840b6aa6818eda5f245ea31f26f115b285368d59ca055 60fe7c2aaf918a226d484621e243219dcddcbd45728fc27293aacb6b354b8dde b5bf8e4ec890f598b350575840d8bd67920c8ef08b1f069c64fb6aea23ecc772 6c470c1214943eb10f1e7513c7f0204952bfe186e240bb7be35f72a81ce57ca2 895906d0cf353816b3c6b5ca825840a9ac8e08a53108e6cb00b623741ede804f c937492bbb6bf934a7fa66ff2a2a925c5ee1bb769df36af4e626ee40940f82a3 078988eca9fad58c9abc883e9ba64e58408cbc64b0742ef7bf0e4bdd9ab2bd00 43cc181ac2ea496c3ddf069c27b338122f501d6df13c9b370612c82b64237d4b 6b80be2b7d7caea69efe0db4c7d6e353d95840f16d662baa168ad898ed65d2b5 36351aaefd52ab9418a1e141d6eebf3511e42866223d18733f7f483bfd581159 4a18f51a2a8232a5d4dad738d4bcccde1928105840da9c58f364176f59dd1096 1cc1036bf4ac74f22b290d327fc45ec00d5834e5dbff6bdff12d140762413d90 a7d6c2275b69fe918cd8fa12a35c51fe4c1cd9a74d5840ab2d7616abc91f9a58 e25fb8181e2ac02315163950cfbe0e1e275b06d7634f093267177c0613108503 1b8574d8b233654f2cf57a50a76e75930cce731b08741d5840826b7c5dbc46b5 2b6c81fff41c9e356c2685290dd85e7315a39a7d46ceabd6ca75e898ad42ce46 ff7ff0171ebcf67be71a23b8f5006a9dc03a8155f5ae12ab8b¶
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'9cb2bf451ee1af22a545f099806cfd150e0f657fc86dc2fe48cb45df4209433e', / 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 6c652e636f6d0758209cb2bf451ee1af22a545f099806cfd150e0f657fc86dc2 fe48cb45df4209433e58cfa701010314057668747470733a2f2f697373756572 2e6578616d706c650687060418aa18ab18b318bb6b6167655f6f7665725f3231 08a40102200121582034417e4dde375ac2a3da65467e07f142ca8df696bda2f7 f644d7383d82caa8c322582017aebf9dafe83e7afc517ed3b618802516849eaa 38c114405ef9375c94cb381409a4010220012158200888e793c6130c8fa78a46 197fc4facfa679a00d2299fa8f1dfc465255a8e7cd2258200dbb3e0c8d7fd112 9356ac04f486518827ef2c5e69566b0e229a3cc75c03fa060a28891a0a382700 1a0a3c3d3f63446f65634a6179726a6179646f65406578616d706c652e6f7267 a601782331323334204d61696e2053742e0a416e79746f776e2c204341203132 3334350a555341026d31323334204d61696e2053742e0367416e79746f776e04 624341056539303231300663555341f5f6f6875840b6aa6818eda5f245ea31f2 6f115b285368d59ca05560fe7c2aaf918a226d484621e243219dcddcbd45728f c27293aacb6b354b8ddeb5bf8e4ec890f598b350575840d8bd67920c8ef08b1f 069c64fb6aea23ecc7726c470c1214943eb10f1e7513c7f0204952bfe186e240 bb7be35f72a81ce57ca2895906d0cf353816b3c6b5ca825840a9ac8e08a53108 e6cb00b623741ede804fc937492bbb6bf934a7fa66ff2a2a925c5ee1bb769df3 6af4e626ee40940f82a3078988eca9fad58c9abc883e9ba64e58408cbc64b074 2ef7bf0e4bdd9ab2bd0043cc181ac2ea496c3ddf069c27b338122f501d6df13c 9b370612c82b64237d4b6b80be2b7d7caea69efe0db4c7d6e353d95840f16d66 2baa168ad898ed65d2b536351aaefd52ab9418a1e141d6eebf3511e42866223d 18733f7f483bfd5811594a18f51a2a8232a5d4dad738d4bcccde1928105840da 9c58f364176f59dd10961cc1036bf4ac74f22b290d327fc45ec00d5834e5dbff 6bdff12d140762413d90a7d6c2275b69fe918cd8fa12a35c51fe4c1cd9a74d58 40d3eb13531d9f31afe24cc0067ef534e05cce49e1bb15d1fc3eb84411010cee 94c04a8ab21a094c07f02cb17e53f536a95df131785310b7effe56a7f11cc8b4 dc¶
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": "FSALHintWxAGnDaZQIwO-8KXo2AhfB465h9Q_p2vmW0gfiyRYqXR6OwZJwvbm
djxCedzqrFRKj7hu6i8opC14UV-7c6aCLywJRC9FIE9O768aYu49LGLQk9pm_C
ZzGxO",
"y": "EDwgBDmAIgsXR54fVmLIwgJNB6TglN5nbiJL-CWUMWivaHMadv6QJZ4Mmp0eX
-v1Ft4tqRplP55QnxACSrpXNR-XvzLx4e9QAP6_kRVt8Idw23DsSpLH7cZCuJt
xTduv",
"d": "QeD17OP-QsO2gwre-0Sh67Ocefp-T748CaWnqOfv0e0"
}
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.ocivOQdcgeStlb0wTpLGl6OOpQzGKAUhkC pDUBamitb4zbT_gSxFmWbNeQIg1K2RUCuytdPurk1ZXvailT1ghpoB93lkBx9VqK1-hdQ Jmuw
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~~~.qZFqpCVx72l_MlRL_XWALbrcJJNY555AtU4WeEqJ -1n_2rI4vIDVW6v6ojuf6s17lb3xypmdxI0ua8_gA75klqMnYYuXhC7QQ_HSiZHSLJ52Y 7341RlHjJ02TD4QBCwZilv6UsILHA626R9uHca10HeMjteOWksOL97YnkxTfnRX0NO26n sQp1nF9-hgJNDxJls2HOcKVZdrmbIxhHhnYFKa6p6rKqxLzkPiZRrD2cchSJ8z9bvkyMz gNFCc5tOYyvXjjZgJkO2rgRWj0UnGzW88-PO7f_jAQVQr97F2eU45r8vQrmI_KCUtxq8I xi-FFuGZDJ31ZLC4sjXVZJgB_nYNDNuudXR7VgMEbh-YVytqN7DIjUyH2dZfRwb1wikAy dX_gpFfRrs0vLBMAKVoriS-Wcr3u60Em0vZ_EQz07Pz7WvHO6oObZVqY_6eEWlpFWiAjE QA-dQ-KT8ogcMcXRrN0-RGnIGthr_xB4jTGjg
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": "a_H-BwPtMTftwSmvcm7IVc4SXVORAZI7-3s1sJadJJc",
"y": "CDrp08C0zI8Fnu2_02neoC4DCrDdhZWasbK-86luj08",
"d": "vewf1OM4w1lPXVc8FjfiDEUL-mRdabs1AhUWIcgTqRc"
}
This is the Issuer's ephemerally generated shared secret:¶
"eHB4gtXM3571_EZkCq7Jtxchd_NOfej5A-3kQTNUWA8"
This is the Holder's presentation private key in the JWK format:¶
{
"kty": "EC",
"crv": "P-256",
"x": "CIjnk8YTDI-nikYZf8T6z6Z5oA0imfqPHfxGUlWo580",
"y": "Dbs-DI1_0RKTVqwE9IZRiCfvLF5pVmsOIpo8x1wD-gY",
"d": "HbSTQhLXQ-UhSSrcINHmZyBFTYUm8jYVv96WRhQkFV4"
}
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": "CIjnk8YTDI-nikYZf8T6z6Z5oA0imfqPHfxGUlWo580",
"y": "Dbs-DI1_0RKTVqwE9IZRiCfvLF5pVmsOIpo8x1wD-gY"
}
}
[
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:¶
[ "9FyemYNWikTGveItu5jwtvtANY0GcrFpiQIafsqeHko", "yVuV3aSouz_ltZYp0WEI_K2E4D4VST8RxEIRbH546NE", "yhsoSM91UsgNyLIi7jqIOIWpo4O6EsujjmTMB6f1Mq4", "B9dviMfkDIxQYk--9gC0LlykV0gb8JngqzeLvv6zhBU", "9xGHe1gwpPMLZCbkoCgxa53qgK6k6UuIdkDYthHFHQw", "2-ZDhjHAjifHFBkffK-QuojeO3jq2dTOf7-s_CsTy_8", "_5ltmA2tXYZHoQCS7Ol8Y-Px4ihD_YgzH8pu4oa9fhY" ]
A MAC is generated for each payload using the corresponding derived payload key. This results in the following set of MAC values:¶
[ "-rvi3PUhQjiV1oInXpeHRc1DrqU7Jk9douxFHIg-0GI", "944v108bxpSSx4WJAmYpGP5RZHmNOIdTy_K27nzxYaE", "3dhW0zUALO4XPcM8nsuq_Rse7dPfxzEq12XMhRcFP6Q", "mI9HriPbQCydpgbN4CSYU1-gV-X-_T4fKi0GXv-ODi4", "TjfJENJVS1LQNSutIKS_8blbNOaJL_k3Qa5aXCTWk8E", "5rzGsqlVqsvhgi1L60joN4Y5OfKnZuyW_i9WTGgv8sk", "Jtonk4Bz8BRFsISJXhdwxLNuKhyJ9cOtuRnbticA4t4" ]
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.¶
[ "k2AL_s8SgbuyEhLpB7mvwMrtNXrXIPv2mryKPWp1jSOf3em6A6ETeOZZPaFgUuCZ8k NIq9BYVLD0QE_tk28d8w", "u-JxVHu0PUwL19KXLZZihXU6GCrap3mQ1RUJIdujgis" ]
The final issued JWP in compact serialization is:¶
eyJhbGciOiJNQUMtSDI1NiIsImhwYSI6IkVTMjU2IiwidHlwIjoiSlBUIiwiaXNzIjoia HR0cHM6Ly9pc3N1ZXIuZXhhbXBsZSIsImNsYWltcyI6WyJpYXQiLCJleHAiLCJmYW1pbH lfbmFtZSIsImdpdmVuX25hbWUiLCJlbWFpbCIsImFkZHJlc3MiLCJhZ2Vfb3Zlcl8yMSJ dLCJocGsiOnsia3R5IjoiRUMiLCJjcnYiOiJQLTI1NiIsInVzZSI6InNpZ24iLCJ4Ijoi Q0lqbms4WVRESS1uaWtZWmY4VDZ6Nlo1b0EwaW1mcVBIZnhHVWxXbzU4MCIsInkiOiJEY nMtREkxXzBSS1RWcXdFOUlaUmlDZnZMRjVwVm1zT0lwbzh4MXdELWdZIn19.MTcxNDUyM TYwMA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheSI~ImpheWRvZUBleGFtcGxlLm9yZyI~eyJm b3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5Bbnl0b3duLCBDQSAxMjM0NVxuVVNBIiwic 3RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4gU3QuIiwibG9jYWxpdHkiOiJBbnl0b3duIi wicmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZSI6MTIzNDUsImNvdW50cnkiOiJVU0EifQ~ dHJ1ZQ.k2AL_s8SgbuyEhLpB7mvwMrtNXrXIPv2mryKPWp1jSOf3em6A6ETeOZZPaFgUu CZ8kNIq9BYVLD0QE_tk28d8w~u-JxVHu0PUwL19KXLZZihXU6GCrap3mQ1RUJIdujgis
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": "nLK_RR7hryKlRfCZgGz9FQ4PZX_IbcL-SMtF30IJQz4"
}
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:¶
[ "k2AL_s8SgbuyEhLpB7mvwMrtNXrXIPv2mryKPWp1jSOf3em6A6ETeOZZPaFgUuCZ8k NIq9BYVLD0QE_tk28d8w", "9FyemYNWikTGveItu5jwtvtANY0GcrFpiQIafsqeHko", "yVuV3aSouz_ltZYp0WEI_K2E4D4VST8RxEIRbH546NE", "yhsoSM91UsgNyLIi7jqIOIWpo4O6EsujjmTMB6f1Mq4", "B9dviMfkDIxQYk--9gC0LlykV0gb8JngqzeLvv6zhBU", "TjfJENJVS1LQNSutIKS_8blbNOaJL_k3Qa5aXCTWk8E", "5rzGsqlVqsvhgi1L60joN4Y5OfKnZuyW_i9WTGgv8sk", "Jtonk4Bz8BRFsISJXhdwxLNuKhyJ9cOtuRnbticA4t4", "MxboV_EnKbRhkOSsZjhxfPuisMxpYpuBYffmgk6FzZpmlwq-7yMTxTScRYP_ZgtTQD OgxoW8FnHMF8d1ptnbSA" ]
The final presented JWP in compact serialization is:¶
eyJhbGciOiJNQUMtSDI1NiIsImF1ZCI6Imh0dHBzOi8vcmVjaXBpZW50LmV4YW1wbGUuY 29tIiwibm9uY2UiOiJuTEtfUlI3aHJ5S2xSZkNaZ0d6OUZRNFBaWF9JYmNMLVNNdEYzME lKUXo0In0.eyJhbGciOiJNQUMtSDI1NiIsImhwYSI6IkVTMjU2IiwidHlwIjoiSlBUIiw iaXNzIjoiaHR0cHM6Ly9pc3N1ZXIuZXhhbXBsZSIsImNsYWltcyI6WyJpYXQiLCJleHAi LCJmYW1pbHlfbmFtZSIsImdpdmVuX25hbWUiLCJlbWFpbCIsImFkZHJlc3MiLCJhZ2Vfb 3Zlcl8yMSJdLCJocGsiOnsia3R5IjoiRUMiLCJjcnYiOiJQLTI1NiIsInVzZSI6InNpZ2 4iLCJ4IjoiQ0lqbms4WVRESS1uaWtZWmY4VDZ6Nlo1b0EwaW1mcVBIZnhHVWxXbzU4MCI sInkiOiJEYnMtREkxXzBSS1RWcXdFOUlaUmlDZnZMRjVwVm1zT0lwbzh4MXdELWdZIn19 .MTcxNDUyMTYwMA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheSI~~~.k2AL_s8SgbuyEhLpB7m vwMrtNXrXIPv2mryKPWp1jSOf3em6A6ETeOZZPaFgUuCZ8kNIq9BYVLD0QE_tk28d8w~9 FyemYNWikTGveItu5jwtvtANY0GcrFpiQIafsqeHko~yVuV3aSouz_ltZYp0WEI_K2E4D 4VST8RxEIRbH546NE~yhsoSM91UsgNyLIi7jqIOIWpo4O6EsujjmTMB6f1Mq4~B9dviMf kDIxQYk--9gC0LlykV0gb8JngqzeLvv6zhBU~TjfJENJVS1LQNSutIKS_8blbNOaJL_k3 Qa5aXCTWk8E~5rzGsqlVqsvhgi1L60joN4Y5OfKnZuyW_i9WTGgv8sk~Jtonk4Bz8BRFs ISJXhdwxLNuKhyJ9cOtuRnbticA4t4~MxboV_EnKbRhkOSsZjhxfPuisMxpYpuBYffmgk 6FzZpmlwq-7yMTxTScRYP_ZgtTQDOgxoW8FnHMF8d1ptnbSA
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¶