| Internet-Draft | json-proof-algorithms | October 2024 |
| Miller, et al. | Expires 23 April 2025 | [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.¶
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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 23 April 2025.¶
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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](#issue), [confirm](#confirm), [present](#present), and [verify](#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 is based on using multiple signatures to cover the individual payloads, all of which are generated with the same Asymmetric JSON Web Algorithm (JWA). The internal signing algorithm to use is part of the registration for a new Single Use algorithm identifier.¶
The chosen JWA MUST be an asymmetric signing algorithm so that each signature can be verified without sharing any private values between the parties. This ensures that the verifier cannot brute force any non-disclosed payloads based only on their disclosed individual signatures.¶
In order to support the protection of a presentation by a holder to a verifier, the holder MUST use a Presentation Key during the issuance and the presentation of every Single Use JWP. This Presentation Key MUST be generated and used for only one JWP.¶
The issuer MUST verify that the holder has possession of this key. The holder-issuer communication to exchange this information is out of scope of this specification, but can be accomplished by the holder using this key to generate a JWS that signs a value the issuer can verify as unique.¶
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 in the issuer protected header via the Proof Key header parameter.¶
The holder's Presentation Key MUST be included in issuer protected header via the Presentation Key header parameter.¶
The issuer protected header is signed using the given JWA and 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.¶
Editor's Note: The current definition here is incomplete, the holder's signature needs to also incorporate the presented proof.¶
The holder derives a new proof as part of presentation. The presented proof value will always contain the issuer's Stable Key signature for the issuer protected header as the first element.¶
The second element of the presented proof is the holder's signature of the presentation protected header using the holder's presentation key. This signature is constructed using the same algorithm described in generating the issuer's signature over the issuer protected header. Signing only the presentation header with the Presentation Key is sufficient to protect the entire presentation since that key is private to the holder and only the contents of the presentation header are used for replay prevention.¶
For each payload which is to be disclosed, the corresponding payload signature (from the issued JWP) is included in the proof. If a payload is omitted from the presented JWP, the signature value will NOT be includeed, and the presentation proof will have one less part.¶
For example, if the second and fifth of five payloads are not disclosed, then the holder's derived proof would consist of the issuer's signature over the issuer protected header, the holder's signature over the holder's protected header, the ephemeral key signature over the first, third and fourth payloads.¶
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.¶
The verifier MUST verify the issuer protected header octets against the first part in the proof using the issuer's Stable Key. It MUST also verify the presentation protected header octets against the second part in the proof value using the holder's Presentation Key, as provided in the Presentation Key header parameter.¶
With the headers verified, the Proof Key header parameter can then be used to verify each of the disclosed payload signatures.¶
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".¶
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 alg parameter value in the issuance protected header corresponds to a ciphersuite identifier of BBS_BLS12381G1_XMD:SHA-256_SSWU_RO_.¶
The BBS-PROOF alg parameter value in the presentation protected header corresponds to the same ciphersuite, but used in presentation form.¶
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 and payloads as the octets header and the octets array 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 Section 3.5.2 of [I-D.irtf-cfrg-bbs-signatures].¶
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 JSON serialization and a zero-length string in compact serialization.¶
Verification of a presentation is done by the verifier using the ProofVerify operation from 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 keys and compute authentication codes to protect the issuer header and each payload individually.¶
Like the 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.¶
Prior to the issuer creating a new JWP, the issuer MUST have a presentation public key provided by the holder.¶
The holder's presentation key MUST be included in the issuer's protected header using the Presentation Key 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 to the holder as part of the issuer's JWP proof value.¶
The Shared Secret is used by both the issuer and holder as the MAC method's key to generate a new set of unique ephemeral keys. These keys are then used as the input to generate a MAC that protects each payload.¶
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 issuer protected header is included in this value as a MAC created using the fixed key "issuer_header" in UTF-8 encoded octets. The value is the issuer header JSON as a UTF-8 encoded octet string.¶
A unique key is generated for each payload using a MAC, with the Shared Secret as the key and a value of "payload_X" as UTF-8 encoded octets, where "X" is replaced by the zero-based array index of the payload, for example "payload_0", "payload_1", etc.¶
Each payload then itself has a corresponding MAC, using the above per-payload key and the payload octet string.¶
The combined MAC representation is the octet string formed by the the concatentation of the issuer protected header MAC output, along with each payload MAC output.¶
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 JWS using its stable public key, and a fixed header containing the alg associated with signing algorithm in use.¶
jws_header = '{"alg":"ES256"}'¶
The signature value of the JWS is extracted and base64url-decoded into an octet string.¶
The second octet string is the Shared Secret used to generate the per-payload keys for the combined representation.¶
See the JWS Presentation Protected Header section.¶
Editor's Note: The current definition here is incomplete, the holder's signature needs to also incorporate the presented proof.¶
The first value in the presentation proof is the presentation signature. This is a signature over the presentation protected header, using the key specified by the Presentation Key header parameter in the issuer protected header.¶
The second value is the issuer signature over the Combined MAC Representation provided with the issued form.¶
The remaining values are used by the verifier to reconstruct the combined MAC representation without access to the Shared Secret. There is one value corresponding to each payload, whether it has been disclosed or not.¶
If a payload is disclosed, the unique per-payload key derived from the shared secret is used as the payload's entry in the proof array.¶
If a payload is not disclosed, the payload's MAC in the combined MAC representation is used as the payload's entry in the proof array.¶
The verifier must recreate the Combined MAC Representation from the presentation proof to verify integrity over the disclosed information.¶
The issuer protected header MAC is recreated using the same mechanism described above.¶
For each payload in the presentation:¶
If the payload is disclosed, then the presentation proof contains the unique per-payload key. The corresponding payload MAC can be computed by performing the MAC operation with this key and the corresponding payload.¶
If the payload is not disclosed, then the presentation proof contains the payload MAC, which can be used directly¶
The concatenation of the octets of the issuer protected header MAC and each payload MAC forms the Combined MAC Representation. The issuer signature in the proof is then verified by converting these values to a JWS as described above, and verifying that JWS.¶
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.¶
Issued or Presented. Other values may be used with the approval of a Designated Expert.¶
SU-ES256¶
Algorithm Analysis Documents(s): n/a¶
Algorithm Name: SU-ES384¶
Algorithm Description: Single-Use JWP using ES384¶
Algorithm Usage Location(s): Issued, Presented¶
JWP Implementation Requirements: Optional¶
Change Controller: IETF¶
Specification Document(s): Section 6.1.11 of this specification¶
Algorithm Analysis Documents(s): n/a¶
Algorithm Name: SU-ES512¶
Algorithm Description: Single-Use JWP using ES512¶
Algorithm Usage Location(s): Issued, Presented¶
JWP Implementation Requirements: Optional¶
Change Controller: IETF¶
Specification Document(s): Section 6.1.11 of this specification¶
Algorithm Analysis Documents(s): n/a¶
Algorithm Name: BBS¶
Algorithm Description: Corresponds to a ciphersuite identifier of BBS_BLS12381G1_XMD:SHA-256_SSWU_RO_H2G_HM2S_¶
Algorithm Usage Location(s): Issued¶
JWP Implementation Requirements: Required¶
Change Controller: IETF¶
Specification Document(s): Section 6.2.1 of this specification¶
Algorithm Analysis Documents(s): n/a¶
Algorithm Name: BBS-PROOF¶
Algorithm Description: Corresponds to a ciphersuite identifier of BBS_BLS12381G1_XMD:SHA-256_SSWU_RO_H2G_HM2S_¶
Algorithm Usage Location(s): Presented¶
JWP Implementation Requirements: Required¶
Change Controller: IETF¶
Specification Document(s): Section 6.2.1 of this specification¶
Algorithm Analysis Documents(s): n/a¶
Algorithm Name: MAC-H256¶
Algorithm Description: MAC-H256 uses HMAC SHA-256 as the MAC and ECDSA using P-256 and SHA-256 for the signatures¶
Algorithm Usage Location(s): Issued, Presented¶
JWP Implementation Requirements: Optional¶
Change Controller: IETF¶
Specification Document(s): Section 6.3.8 of this specification¶
Algorithm Analysis Documents(s): n/a¶
Algorithm Name: MAC-H384¶
Algorithm Description: MAC-H384 uses HMAC SHA-384 as the MAC and ECDSA using P-384 and SHA-384 for the signatures¶
Algorithm Usage Location(s): Issued, Presented¶
JWP Implementation Requirements: Optional¶
Change Controller: IETF¶
Specification Document(s): Section 6.3.8 of this specification¶
Algorithm Analysis Documents(s): n/a¶
Algorithm Name: MAC-H512¶
Algorithm Description: MAC-H512 uses HMAC SHA-512 as the MAC and ECDSA using P-521 and SHA-512 for the signatures¶
Algorithm Usage Location(s): Issued, Presented¶
JWP Implementation Requirements: Optional¶
Change Controller: IETF¶
Specification Document(s): Section 6.3.8 of this specification¶
Algorithm Analysis Documents(s): n/a¶
Algorithm Name: MAC-K25519¶
Algorithm Description: MAC-K25519 uses KMAC SHAKE128 as the MAC and EdDSA using Curve25519 for the signatures¶
Algorithm Usage Location(s): Issued, Presented¶
JWP Implementation Requirements: Optional¶
Change Controller: IETF¶
Specification Document(s): Section 6.3.8 of this specification¶
Algorithm Analysis Documents(s): n/a¶
Algorithm Name: MAC-K448¶
Algorithm Description: MAC-K448 uses KMAC SHAKE256 as the MAC and EdDSA using Curve448 for the signatures¶
Algorithm Usage Location(s): Issued, Presented¶
JWP Implementation Requirements: Optional¶
Change Controller: IETF¶
Specification Document(s): Section 6.3.8 of this specification¶
Algorithm Analysis Documents(s): n/a¶
Algorithm Name: MAC-H256K¶
Algorithm Description: MAC-H256K uses HMAC SHA-256 as the MAC and ECDSA using secp256k1 and SHA-256 for the signatures¶
Algorithm Usage Location(s): Issued, Presented¶
JWP Implementation Requirements: Optional¶
Change Controller: IETF¶
Specification Document(s): Section 6.3.8 of this specification¶
Algorithm Analysis Documents(s): n/a¶
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": "pzMDnFm276MWHanezCmgEvM4wes1D3_tljLefWArh00",
"y": "bY0pN9wbZcEqeelQl4h6VrTL1B2lqrGbclXVtPSXyNQ",
"d": "lEUt-XH6RypYGX641SppLWYTjg5E5tZPz7ZLbYLhBdQ"
}
This is the ephemeral private key used in this example in the JWK format:¶
{
"kty": "EC",
"crv": "P-256",
"x": "JgwWcXLBzGyZ68xQBYi0JvfaBGF-ZY-0MYNukBw7vc4",
"y": "rwseMlI_w7Jm59UpyDuRymIsabeUVtQnx8VWDeP7pa0",
"d": "TG0FIupkUle1gOfSdTA0RzfqUqajwCYSBnGUAteNhWQ"
}
This is the Holder's presentation private key used in this example in the JWK format:¶
{
"kty": "EC",
"crv": "P-256",
"x": "tGifglj945MmxrAvPG5gG3qnpRaROI8cbX-hD-NP56E",
"y": "sK9uyO8x-ZklMdMr4Si4efOgc4EIzSBzrN38zENA1WQ",
"d": "Nk64GcI4Fb0jqJjIFLEdxMfcJC1VFVyEpKFvTiEkO4s"
}
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",
"claims": [
"iat",
"exp",
"family_name",
"given_name",
"email",
"address",
"age_over_21"
],
"proof_key": {
"kty": "EC",
"crv": "P-256",
"x": "JgwWcXLBzGyZ68xQBYi0JvfaBGF-ZY-0MYNukBw7vc4",
"y": "rwseMlI_w7Jm59UpyDuRymIsabeUVtQnx8VWDeP7pa0",
"d": "TG0FIupkUle1gOfSdTA0RzfqUqajwCYSBnGUAteNhWQ"
},
"presentation_key": {
"kty": "EC",
"crv": "P-256",
"x": "tGifglj945MmxrAvPG5gG3qnpRaROI8cbX-hD-NP56E",
"y": "sK9uyO8x-ZklMdMr4Si4efOgc4EIzSBzrN38zENA1WQ",
"d": "Nk64GcI4Fb0jqJjIFLEdxMfcJC1VFVyEpKFvTiEkO4s"
}
}
The JWP Protected Header JSON is serialized (without the above whitespace added for readability) and uses UTF-8 encoding to convert into an octet string. This gives:¶
eyJhbGciOiJTVS1FUzI1NiIsInR5cCI6IkpQVCIsImlzcyI6Imh0dHBzOi8vaXNzdWVyL mV4YW1wbGUiLCJjbGFpbXMiOlsiaWF0IiwiZXhwIiwiZmFtaWx5X25hbWUiLCJnaXZlbl 9uYW1lIiwiZW1haWwiLCJhZGRyZXNzIiwiYWdlX292ZXJfMjEiXSwicHJvb2Zfa2V5Ijp 7Imt0eSI6IkVDIiwiY3J2IjoiUC0yNTYiLCJ4IjoiSmd3V2NYTEJ6R3laNjh4UUJZaTBK dmZhQkdGLVpZLTBNWU51a0J3N3ZjNCIsInkiOiJyd3NlTWxJX3c3Sm01OVVweUR1UnltS XNhYmVVVnRRbng4VldEZVA3cGEwIiwiZCI6IlRHMEZJdXBrVWxlMWdPZlNkVEEwUnpmcV VxYWp3Q1lTQm5HVUF0ZU5oV1EifSwicHJlc2VudGF0aW9uX2tleSI6eyJrdHkiOiJFQyI sImNydiI6IlAtMjU2IiwieCI6InRHaWZnbGo5NDVNbXhyQXZQRzVnRzNxbnBSYVJPSThj YlgtaEQtTlA1NkUiLCJ5Ijoic0s5dXlPOHgtWmtsTWRNcjRTaTRlZk9nYzRFSXpTQnpyT jM4ekVOQTFXUSIsImQiOiJOazY0R2NJNEZiMGpxSmpJRkxFZHhNZmNKQzFWRlZ5RXBLRn ZUaUVrTzRzIn19
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.¶
The resulting JSON serialized JPT using the above examples is:¶
{
"issuer": "eyJhbGciOiJTVS1FUzI1NiIsInR5cCI6IkpQVCIsImlzcyI6Imh0dHBz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",
"payloads": [
"MTcxNDUyMTYwMA",
"MTcxNzE5OTk5OQ",
"IkRvZSI",
"IkpheSI",
"ImpheWRvZUBleGFtcGxlLm9yZyI",
"eyJmb3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5Bbnl0b3duLCBDQSAxMjM0NVxu
VVNBIiwic3RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4gU3QuIiwibG9jYWxpdH
kiOiJBbnl0b3duIiwicmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZSI6MTIzNDUs
ImNvdW50cnkiOiJVU0EifQ",
"dHJ1ZQ"
],
"proof": [
"nVD43BB5hnusxQND8KrK7zO_Ew28xJ4S5puYliKi57PFWaKDdvKc9pNw-4pxsjTT
6ezWNy2V7vvCOgCtYxXZyg",
"qesBQncQKFy7UFilfODDs806dkzEpzg1NnQmLpOtpjraFIqIiL2-sVQuTjNjg9Y0
jv9snpufH-W7X7XpFmy-Wg",
"S7cGL4I8IxsTrTeijYGHEGG1p2yK0k6DpzvDR6yGzME81q_rIaEDZzJlmbOGxUK8
sM9nAKgewhBfY-d4rmd_lg",
"bq_qoH6cL6ENiTgAYVdU8gJZ2QNquIgYO01QnwN9JISWncDWarLJ1hSj7z1ix1jp
_4qoNh7TR5n4f9URDQTAqQ",
"IrWb3VjHsCmgHUHsFzi0K-pSvUWFCx7YVTw2FVF8VvZteqEhwTRp0WBS6yTI5obO
aNML1_M1zP3L-mwxXF2jNQ",
"MmMZiU2IWB4c6P1BmztXQsBGtaVK0Q_yRc5ETy0hh2UsR-WczopV0ls7QmWGej8I
cjfmdEzFVKDesGqZKdnb0Q",
"AiUEERwP5X9JrHPLOGXja9IO5kU7mMQjezJThmzlunw6_IhlKBUHv6Zoa9_o2qgP
FmlB6wEuh40Y2ANvkqFshg",
"SEiGXa4mgFiUt1jBfttXX8TiKFh6Tm0bc5rR-mc10LXxLdRgsgH_OiGBHA9J3vTT
Stx8jSb1PZCJYWVOjEQ8sg"
]
}
The compact serialization of the same JPT is:¶
eyJhbGciOiJTVS1FUzI1NiIsInR5cCI6IkpQVCIsImlzcyI6Imh0dHBzOi8vaXNzdWVyL mV4YW1wbGUiLCJjbGFpbXMiOlsiaWF0IiwiZXhwIiwiZmFtaWx5X25hbWUiLCJnaXZlbl 9uYW1lIiwiZW1haWwiLCJhZGRyZXNzIiwiYWdlX292ZXJfMjEiXSwicHJvb2Zfa2V5Ijp 7Imt0eSI6IkVDIiwiY3J2IjoiUC0yNTYiLCJ4IjoiSmd3V2NYTEJ6R3laNjh4UUJZaTBK dmZhQkdGLVpZLTBNWU51a0J3N3ZjNCIsInkiOiJyd3NlTWxJX3c3Sm01OVVweUR1UnltS XNhYmVVVnRRbng4VldEZVA3cGEwIiwiZCI6IlRHMEZJdXBrVWxlMWdPZlNkVEEwUnpmcV VxYWp3Q1lTQm5HVUF0ZU5oV1EifSwicHJlc2VudGF0aW9uX2tleSI6eyJrdHkiOiJFQyI sImNydiI6IlAtMjU2IiwieCI6InRHaWZnbGo5NDVNbXhyQXZQRzVnRzNxbnBSYVJPSThj YlgtaEQtTlA1NkUiLCJ5Ijoic0s5dXlPOHgtWmtsTWRNcjRTaTRlZk9nYzRFSXpTQnpyT jM4ekVOQTFXUSIsImQiOiJOazY0R2NJNEZiMGpxSmpJRkxFZHhNZmNKQzFWRlZ5RXBLRn ZUaUVrTzRzIn19.MTcxNDUyMTYwMA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheSI~ImpheWRv ZUBleGFtcGxlLm9yZyI~eyJmb3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5Bbnl0b3duL CBDQSAxMjM0NVxuVVNBIiwic3RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4gU3QuIiwibG 9jYWxpdHkiOiJBbnl0b3duIiwicmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZSI6MTIzNDU sImNvdW50cnkiOiJVU0EifQ~dHJ1ZQ.nVD43BB5hnusxQND8KrK7zO_Ew28xJ4S5puYli Ki57PFWaKDdvKc9pNw-4pxsjTT6ezWNy2V7vvCOgCtYxXZyg~qesBQncQKFy7UFilfODD s806dkzEpzg1NnQmLpOtpjraFIqIiL2-sVQuTjNjg9Y0jv9snpufH-W7X7XpFmy-Wg~S7 cGL4I8IxsTrTeijYGHEGG1p2yK0k6DpzvDR6yGzME81q_rIaEDZzJlmbOGxUK8sM9nAKg ewhBfY-d4rmd_lg~bq_qoH6cL6ENiTgAYVdU8gJZ2QNquIgYO01QnwN9JISWncDWarLJ1 hSj7z1ix1jp_4qoNh7TR5n4f9URDQTAqQ~IrWb3VjHsCmgHUHsFzi0K-pSvUWFCx7YVTw 2FVF8VvZteqEhwTRp0WBS6yTI5obOaNML1_M1zP3L-mwxXF2jNQ~MmMZiU2IWB4c6P1Bm ztXQsBGtaVK0Q_yRc5ETy0hh2UsR-WczopV0ls7QmWGej8IcjfmdEzFVKDesGqZKdnb0Q ~AiUEERwP5X9JrHPLOGXja9IO5kU7mMQjezJThmzlunw6_IhlKBUHv6Zoa9_o2qgPFmlB 6wEuh40Y2ANvkqFshg~SEiGXa4mgFiUt1jBfttXX8TiKFh6Tm0bc5rR-mc10LXxLdRgsg H_OiGBHA9J3vTTStx8jSb1PZCJYWVOjEQ8sg
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": "1oz55t7MsNmYF-DDbiJ-F7q2-XCIswQSs-My5WFp2rY"
}
This header is serialized without whitespace and UTF-8 encoded into an octet string. This gives:¶
eyJhbGciOiJTVS1FUzI1NiIsImF1ZCI6Imh0dHBzOi8vcmVjaXBpZW50LmV4YW1wbGUuY 29tIiwibm9uY2UiOiIxb3o1NXQ3TXNObVlGLUREYmlKLUY3cTItWENJc3dRU3MtTXk1V0 ZwMnJZIn0
When signed with the holder's presentation key, the resulting signature are:¶
GBxRogO7c5LDzArSPXfTkXovRpemTmCFaRYC6R4M_GEZNak-uTy2o_8zq1ZcMhYZlwFu4 YJZOWnxzb0lTOas2w¶
Figure: Holder Proof-of-Possession (base64url-encoded)¶
Then by applying selective disclosure of only the given name and age claims (family name and email hidden), we get the following presented JPT:¶
{
"presentation": "eyJhbGciOiJTVS1FUzI1NiIsImF1ZCI6Imh0dHBzOi8vcmVjaX
BpZW50LmV4YW1wbGUuY29tIiwibm9uY2UiOiIxb3o1NXQ3TXNObVlGLUREYmlK
LUY3cTItWENJc3dRU3MtTXk1V0ZwMnJZIn0",
"issuer": "eyJhbGciOiJTVS1FUzI1NiIsInR5cCI6IkpQVCIsImlzcyI6Imh0dHBz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",
"payloads": [
"MTcxNDUyMTYwMA",
"MTcxNzE5OTk5OQ",
"IkRvZSI",
"IkpheSI",
"ImpheWRvZUBleGFtcGxlLm9yZyI",
"eyJmb3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5Bbnl0b3duLCBDQSAxMjM0NVxu
VVNBIiwic3RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4gU3QuIiwibG9jYWxpdH
kiOiJBbnl0b3duIiwicmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZSI6MTIzNDUs
ImNvdW50cnkiOiJVU0EifQ",
"dHJ1ZQ",
null,
null
],
"proof": [
"nVD43BB5hnusxQND8KrK7zO_Ew28xJ4S5puYliKi57PFWaKDdvKc9pNw-4pxsjTT
6ezWNy2V7vvCOgCtYxXZyg",
"GBxRogO7c5LDzArSPXfTkXovRpemTmCFaRYC6R4M_GEZNak-uTy2o_8zq1ZcMhYZ
lwFu4YJZOWnxzb0lTOas2w",
"qesBQncQKFy7UFilfODDs806dkzEpzg1NnQmLpOtpjraFIqIiL2-sVQuTjNjg9Y0
jv9snpufH-W7X7XpFmy-Wg",
"S7cGL4I8IxsTrTeijYGHEGG1p2yK0k6DpzvDR6yGzME81q_rIaEDZzJlmbOGxUK8
sM9nAKgewhBfY-d4rmd_lg",
"bq_qoH6cL6ENiTgAYVdU8gJZ2QNquIgYO01QnwN9JISWncDWarLJ1hSj7z1ix1jp
_4qoNh7TR5n4f9URDQTAqQ",
"IrWb3VjHsCmgHUHsFzi0K-pSvUWFCx7YVTw2FVF8VvZteqEhwTRp0WBS6yTI5obO
aNML1_M1zP3L-mwxXF2jNQ",
"MmMZiU2IWB4c6P1BmztXQsBGtaVK0Q_yRc5ETy0hh2UsR-WczopV0ls7QmWGej8I
cjfmdEzFVKDesGqZKdnb0Q"
]
}
¶
Figure: Final Presentation in JSON Serialization¶
And also in compact serialization:¶
eyJhbGciOiJTVS1FUzI1NiIsImF1ZCI6Imh0dHBzOi8vcmVjaXBpZW50LmV4YW1wbGUuY 29tIiwibm9uY2UiOiIxb3o1NXQ3TXNObVlGLUREYmlKLUY3cTItWENJc3dRU3MtTXk1V0 ZwMnJZIn0.eyJhbGciOiJTVS1FUzI1NiIsInR5cCI6IkpQVCIsImlzcyI6Imh0dHBzOi8 vaXNzdWVyLmV4YW1wbGUiLCJjbGFpbXMiOlsiaWF0IiwiZXhwIiwiZmFtaWx5X25hbWUi LCJnaXZlbl9uYW1lIiwiZW1haWwiLCJhZGRyZXNzIiwiYWdlX292ZXJfMjEiXSwicHJvb 2Zfa2V5Ijp7Imt0eSI6IkVDIiwiY3J2IjoiUC0yNTYiLCJ4IjoiSmd3V2NYTEJ6R3laNj h4UUJZaTBKdmZhQkdGLVpZLTBNWU51a0J3N3ZjNCIsInkiOiJyd3NlTWxJX3c3Sm01OVV weUR1UnltSXNhYmVVVnRRbng4VldEZVA3cGEwIiwiZCI6IlRHMEZJdXBrVWxlMWdPZlNk VEEwUnpmcVVxYWp3Q1lTQm5HVUF0ZU5oV1EifSwicHJlc2VudGF0aW9uX2tleSI6eyJrd HkiOiJFQyIsImNydiI6IlAtMjU2IiwieCI6InRHaWZnbGo5NDVNbXhyQXZQRzVnRzNxbn BSYVJPSThjYlgtaEQtTlA1NkUiLCJ5Ijoic0s5dXlPOHgtWmtsTWRNcjRTaTRlZk9nYzR FSXpTQnpyTjM4ekVOQTFXUSIsImQiOiJOazY0R2NJNEZiMGpxSmpJRkxFZHhNZmNKQzFW RlZ5RXBLRnZUaUVrTzRzIn19.MTcxNDUyMTYwMA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheS I~ImpheWRvZUBleGFtcGxlLm9yZyI~eyJmb3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5 Bbnl0b3duLCBDQSAxMjM0NVxuVVNBIiwic3RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4g U3QuIiwibG9jYWxpdHkiOiJBbnl0b3duIiwicmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZ SI6MTIzNDUsImNvdW50cnkiOiJVU0EifQ~dHJ1ZQ~~.nVD43BB5hnusxQND8KrK7zO_Ew 28xJ4S5puYliKi57PFWaKDdvKc9pNw-4pxsjTT6ezWNy2V7vvCOgCtYxXZyg~GBxRogO7 c5LDzArSPXfTkXovRpemTmCFaRYC6R4M_GEZNak-uTy2o_8zq1ZcMhYZlwFu4YJZOWnxz b0lTOas2w~qesBQncQKFy7UFilfODDs806dkzEpzg1NnQmLpOtpjraFIqIiL2-sVQuTjN jg9Y0jv9snpufH-W7X7XpFmy-Wg~S7cGL4I8IxsTrTeijYGHEGG1p2yK0k6DpzvDR6yGz ME81q_rIaEDZzJlmbOGxUK8sM9nAKgewhBfY-d4rmd_lg~bq_qoH6cL6ENiTgAYVdU8gJ Z2QNquIgYO01QnwN9JISWncDWarLJ1hSj7z1ix1jp_4qoNh7TR5n4f9URDQTAqQ~IrWb3 VjHsCmgHUHsFzi0K-pSvUWFCx7YVTw2FVF8VvZteqEhwTRp0WBS6yTI5obOaNML1_M1zP 3L-mwxXF2jNQ~MmMZiU2IWB4c6P1BmztXQsBGtaVK0Q_yRc5ETy0hh2UsR-WczopV0ls7 QmWGej8IcjfmdEzFVKDesGqZKdnb0Q¶
Figure: Final Presentation in Compact Serialization¶
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": "BVXNoVaRkxj1Yy0Ld9MeO-WzwqJW5SAw4lM-W6vwU-gX3XG0kSpXfV4xWfOUG
ei-DtomPUTJO9ZS1CvNKaww3iIXX3e0uTQslTS06_HrS46KZ_5TAYZdK0PJnoz
5JH_l",
"y": "BBg4gj2raIK-GZfFiqmpRm56i9tZRMq2wKl28IC7woKDQQjxubOaEtKLgeS4c
_KKAVViYCCHdYiG2U9Hvm6xHjbAoAtBDOqzQ7klOgmTuO1E8kVv5VgS6kyiaK0
WTVWW",
"d": "ZBz1X_ICXsp0lFEUbk1fgISqAcQYNk7QbL3_qUMuJAg"
}
There is no additional holder key necessary for presentation proofs.¶
For the following protected header and array of payloads:¶
{
"kid": "HjfcpyjuZQ-O8Ye2hQnNbT9RbbnrobptdnExR0DUjU8",
"alg": "BBS"
}
[
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
]
These components are signed using the private issuer key previously given, which is then representable in the following serializations:¶
{
"issuer": "eyJraWQiOiJIamZjcHlqdVpRLU84WWUyaFFuTmJUOVJiYm5yb2JwdGRu
RXhSMERValU4IiwiYWxnIjoiQkJTIn0",
"payloads": [
"MTcxNDUyMTYwMA",
"MTcxNzE5OTk5OQ",
"IkRvZSI",
"IkpheSI",
"ImpheWRvZUBleGFtcGxlLm9yZyI",
"eyJmb3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5Bbnl0b3duLCBDQSAxMjM0NVxu
VVNBIiwic3RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4gU3QuIiwibG9jYWxpdH
kiOiJBbnl0b3duIiwicmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZSI6MTIzNDUs
ImNvdW50cnkiOiJVU0EifQ",
"dHJ1ZQ"
],
"proof": [
"quJgXaSapb-fkPP7FAMrRq5Bbfm7pvai2B9p3jbMXh-ZgWum7BdEZvOmMvO6D16e
aVag5K_bWaDya9inyrZ1OAbalzZ-tgacyOB3Gvv_ifY"
]
}
eyJraWQiOiJIamZjcHlqdVpRLU84WWUyaFFuTmJUOVJiYm5yb2JwdGRuRXhSMERValU4I iwiYWxnIjoiQkJTIn0.MTcxNDUyMTYwMA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheSI~Imph eWRvZUBleGFtcGxlLm9yZyI~eyJmb3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5Bbnl0b 3duLCBDQSAxMjM0NVxuVVNBIiwic3RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4gU3QuIi wibG9jYWxpdHkiOiJBbnl0b3duIiwicmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZSI6MTI zNDUsImNvdW50cnkiOiJVU0EifQ~dHJ1ZQ.quJgXaSapb-fkPP7FAMrRq5Bbfm7pvai2B 9p3jbMXh-ZgWum7BdEZvOmMvO6D16eaVag5K_bWaDya9inyrZ1OAbalzZ-tgacyOB3Gvv _ifY
For a presentation with the following presentation header:¶
{
"alg": "BBS-PROOF",
"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 serializations:¶
{
"presentation": "eyJhbGciOiJCQlMtUFJPT0YiLCJhdWQiOiJodHRwczovL3JlY2
lwaWVudC5leGFtcGxlLmNvbSIsIm5vbmNlIjoid3JtQlJrS3RYalEifQ",
"issuer": "eyJraWQiOiJIamZjcHlqdVpRLU84WWUyaFFuTmJUOVJiYm5yb2JwdGRu
RXhSMERValU4IiwiYWxnIjoiQkJTIn0",
"payloads": [
"MTcxNDUyMTYwMA",
"MTcxNzE5OTk5OQ",
"IkRvZSI",
"IkpheSI",
null,
null,
null
],
"proof": [
"qlvStAzsD7BH4TvIMAEhZ6KjBzCLmH9IM1eXKEzfGbHQme3KIeE6z7siLDB1vcWs
jiaHT_Us-BvVXGvy97CGUHmFK1UD47EZUU8gOHiI9aPGfzC_XFH0ZZ6Q1IrV-C
RXsqdvLvlAKEoMI4vRJUV72Jzpy-FkwvyXcIJiUmy8QqE0zb_nYSYvGEe5hqaq
3YgrcnK4W1YUwPNydwOqL2QNGpvy4r4Ejl0evwHw9E8CV8hMQH1eYsI7t8Jirx
J9UrQi5t5rNuQ5owDRQru2oOjbVTyujb1yqpePpBHwOgLzGEjVpRDaCKFe19ti
6VclkoAZctswLIE0x3UtxFve-1epW9i_KZU9MSoV4VjxmkQ6PUE016p3eD39hs
FY-Th8uoz9pKMgw8FsXVrF_Hoj4G6WogiP1M7Oa7qsHKbcTN5ayIJDhazIY-at
Fzf7UJjA4daEWyMB32bVkiDuuJomJgUjefiJRT8nmJdSq33sHkHd6VM"
]
}
eyJhbGciOiJCQlMtUFJPT0YiLCJhdWQiOiJodHRwczovL3JlY2lwaWVudC5leGFtcGxlL mNvbSIsIm5vbmNlIjoid3JtQlJrS3RYalEifQ.eyJraWQiOiJIamZjcHlqdVpRLU84WWU yaFFuTmJUOVJiYm5yb2JwdGRuRXhSMERValU4IiwiYWxnIjoiQkJTIn0.MTcxNDUyMTYw MA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheSI~~~.qlvStAzsD7BH4TvIMAEhZ6KjBzCLmH9I M1eXKEzfGbHQme3KIeE6z7siLDB1vcWsjiaHT_Us-BvVXGvy97CGUHmFK1UD47EZUU8gO HiI9aPGfzC_XFH0ZZ6Q1IrV-CRXsqdvLvlAKEoMI4vRJUV72Jzpy-FkwvyXcIJiUmy8Qq E0zb_nYSYvGEe5hqaq3YgrcnK4W1YUwPNydwOqL2QNGpvy4r4Ejl0evwHw9E8CV8hMQH1 eYsI7t8JirxJ9UrQi5t5rNuQ5owDRQru2oOjbVTyujb1yqpePpBHwOgLzGEjVpRDaCKFe 19ti6VclkoAZctswLIE0x3UtxFve-1epW9i_KZU9MSoV4VjxmkQ6PUE016p3eD39hsFY- Th8uoz9pKMgw8FsXVrF_Hoj4G6WogiP1M7Oa7qsHKbcTN5ayIJDhazIY-atFzf7UJjA4d aEWyMB32bVkiDuuJomJgUjefiJRT8nmJdSq33sHkHd6VM
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": "pzMDnFm276MWHanezCmgEvM4wes1D3_tljLefWArh00",
"y": "bY0pN9wbZcEqeelQl4h6VrTL1B2lqrGbclXVtPSXyNQ",
"d": "lEUt-XH6RypYGX641SppLWYTjg5E5tZPz7ZLbYLhBdQ"
}
This is the Issuer's ephemerally generated shared secret:¶
"Zv7ckfiZBZVseP4TmWLR0TjpXotWhdW2TVkzkrkGW9w"
This is the Holder's presentation private key in the JWK format:¶
{
"kty": "EC",
"crv": "P-256",
"x": "tGifglj945MmxrAvPG5gG3qnpRaROI8cbX-hD-NP56E",
"y": "sK9uyO8x-ZklMdMr4Si4efOgc4EIzSBzrN38zENA1WQ",
"d": "Nk64GcI4Fb0jqJjIFLEdxMfcJC1VFVyEpKFvTiEkO4s"
}
For the following protected header and array of payloads:¶
{
"alg": "MAC-H256",
"typ": "JPT",
"iss": "https://issuer.example",
"claims": [
"iat",
"exp",
"family_name",
"given_name",
"email",
"address",
"age_over_21"
],
"presentation_key": {
"kty": "EC",
"crv": "P-256",
"use": "sign",
"x": "tGifglj945MmxrAvPG5gG3qnpRaROI8cbX-hD-NP56E",
"y": "sK9uyO8x-ZklMdMr4Si4efOgc4EIzSBzrN38zENA1WQ"
}
}
[
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 first MAC is generated using the key issuer_header and a value of the issuer protected header as a UTF-8 encoded octet string. This results in the following MAC:¶
_2rqU0iNqAWOdrd_LW6rTntERpjn0OhHX-myECgsVjw
The issuer generates an array of derived keys with one for each payload by using the shared secret as the key, and the index of the payload (as payload_{n} in UTF-8 encoded octets) as the input in a HMAC operation. This results in the following set of derived keys:¶
[ "eNfsgemstMwHlIF0VyLHnPhezehniBqQ5_YA5ceb4y8", "26hywboboVLNaB2Msj7gvSGpyhn9e_qv_DfK37Fr0G8", "9GM9wTy56XMB38wZGHlYGA9yVmHZ1zswTU1fhxMti88", "S8kVw7p7WoymaNMxkLFfRxJ4Hu6S4Du-C2Xln8tXabw", "aO2VpEcqFFIUhY74Xukit2ZlUgYiVwJt9s_Rgp72xyA", "CS_7WEpA6uXqn1VL64bGwx0zSfV-imeDDOP-0SQ2XR8", "cLO-JaFFcgs1fzwo7r6GCgFQMq4hBA7dffXoSv5hf9s" ]
A MAC is generated for each payload using the corresponding derived payload key. This results in the following set of MAC values:¶
[ "TEfMllwZFf1jtfgq5r3Ab51ZeNjKOaH1nTPmuXzroUg", "52kbsWvq9szR4T8jk5xcYV8GG8u8uNT8kHntAQCoFjk", "f8q3BgsDW29RZT4YlenQoIsKUhtNTESihwpDS2estuo", "GFKNK6DyOUckIDgovwLyqSZGZk6fKpSV5TrBmfLSI1o", "XmB-WYWx9-2RmMAXYw1QueXyzOFb1Pw0_TjRigfbb4M", "lRRFh83TgTd8eYq2fQ7IrnGqBaYEJSc_xAhq63KzZkk", "OYM9ZpgAv65pLgATwXk_qSW34tp-RabagVifmtELC7A" ]
The issuer protected header MAC and the payload MAC octet strings are concatenated into a single value known as the combined 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.¶
[ "b2F3U2oZ29fnxokfZpdfk8oJZVv6aYVZptq8l-9RJ2ypeZNjENMDQlPxWQRMkzU8zy -JCQ6XaSrWl0HPa2fD9w", "yXqtYZeoNwJEQ6YoxV09UFgE_ycdf44jooMJldjSLwk" ]
The final issued JWP in JSON serialization is:¶
{
"issuer": "eyJhbGciOiJNQUMtSDI1NiIsInR5cCI6IkpQVCIsImlzcyI6Imh0dHBz
Oi8vaXNzdWVyLmV4YW1wbGUiLCJjbGFpbXMiOlsiaWF0IiwiZXhwIiwiZmFtaWx5X25hb
WUiLCJnaXZlbl9uYW1lIiwiZW1haWwiLCJhZGRyZXNzIiwiYWdlX292ZXJfMjEiXSwicH
Jlc2VudGF0aW9uX2tleSI6eyJrdHkiOiJFQyIsImNydiI6IlAtMjU2IiwidXNlIjoic2l
nbiIsIngiOiJ0R2lmZ2xqOTQ1TW14ckF2UEc1Z0czcW5wUmFST0k4Y2JYLWhELU5QNTZF
IiwieSI6InNLOXV5Tzh4LVprbE1kTXI0U2k0ZWZPZ2M0RUl6U0J6ck4zOHpFTkExV1Eif
X0",
"payloads": [
"MTcxNDUyMTYwMA",
"MTcxNzE5OTk5OQ",
"IkRvZSI",
"IkpheSI",
"ImpheWRvZUBleGFtcGxlLm9yZyI",
"eyJmb3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5Bbnl0b3duLCBDQSAxMjM0NVxu
VVNBIiwic3RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4gU3QuIiwibG9jYWxpdHkiOiJBb
nl0b3duIiwicmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZSI6MTIzNDUsImNvdW50cnkiOi
JVU0EifQ",
"dHJ1ZQ"
],
"proof": [
"b2F3U2oZ29fnxokfZpdfk8oJZVv6aYVZptq8l-9RJ2ypeZNjENMDQlPxWQRMkzU8
zy-JCQ6XaSrWl0HPa2fD9w",
"yXqtYZeoNwJEQ6YoxV09UFgE_ycdf44jooMJldjSLwk"
]
}
The same JWP in compact serialization:¶
eyJhbGciOiJNQUMtSDI1NiIsInR5cCI6IkpQVCIsImlzcyI6Imh0dHBzOi8vaXNzdWVyL mV4YW1wbGUiLCJjbGFpbXMiOlsiaWF0IiwiZXhwIiwiZmFtaWx5X25hbWUiLCJnaXZlbl 9uYW1lIiwiZW1haWwiLCJhZGRyZXNzIiwiYWdlX292ZXJfMjEiXSwicHJlc2VudGF0aW9 uX2tleSI6eyJrdHkiOiJFQyIsImNydiI6IlAtMjU2IiwidXNlIjoic2lnbiIsIngiOiJ0 R2lmZ2xqOTQ1TW14ckF2UEc1Z0czcW5wUmFST0k4Y2JYLWhELU5QNTZFIiwieSI6InNLO XV5Tzh4LVprbE1kTXI0U2k0ZWZPZ2M0RUl6U0J6ck4zOHpFTkExV1EifX0.MTcxNDUyMT YwMA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheSI~ImpheWRvZUBleGFtcGxlLm9yZyI~eyJmb 3JtYXR0ZWQiOiIxMjM0IE1haW4gU3QuXG5Bbnl0b3duLCBDQSAxMjM0NVxuVVNBIiwic3 RyZWV0X2FkZHJlc3MiOiIxMjM0IE1haW4gU3QuIiwibG9jYWxpdHkiOiJBbnl0b3duIiw icmVnaW9uIjoiQ0EiLCJwb3N0YWxfY29kZSI6MTIzNDUsImNvdW50cnkiOiJVU0EifQ~d HJ1ZQ.b2F3U2oZ29fnxokfZpdfk8oJZVv6aYVZptq8l-9RJ2ypeZNjENMDQlPxWQRMkzU 8zy-JCQ6XaSrWl0HPa2fD9w~yXqtYZeoNwJEQ6YoxV09UFgE_ycdf44jooMJldjSLwk
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": "1oz55t7MsNmYF-DDbiJ-F7q2-XCIswQSs-My5WFp2rY"
}
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 the disclosed payloads, the holder will provide the corresponding derived key. For the non-disclosed payloads, 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:¶
[ "oYu2l2ezvYtrY7dKisbNWSUGlKNhwOp3StAnNJetQu4oscuJFGGuxMwI7k7bTwKoZw K_K5Mv8WP3GOsx0zmZWQ", "b2F3U2oZ29fnxokfZpdfk8oJZVv6aYVZptq8l-9RJ2ypeZNjENMDQlPxWQRMkzU8zy -JCQ6XaSrWl0HPa2fD9w", "eNfsgemstMwHlIF0VyLHnPhezehniBqQ5_YA5ceb4y8", "26hywboboVLNaB2Msj7gvSGpyhn9e_qv_DfK37Fr0G8", "9GM9wTy56XMB38wZGHlYGA9yVmHZ1zswTU1fhxMti88", "S8kVw7p7WoymaNMxkLFfRxJ4Hu6S4Du-C2Xln8tXabw", "XmB-WYWx9-2RmMAXYw1QueXyzOFb1Pw0_TjRigfbb4M", "lRRFh83TgTd8eYq2fQ7IrnGqBaYEJSc_xAhq63KzZkk", "OYM9ZpgAv65pLgATwXk_qSW34tp-RabagVifmtELC7A" ]
The final presented JWP in JSON serialization is:¶
{
"presentation": "eyJhbGciOiJNQUMtSDI1NiIsImF1ZCI6Imh0dHBzOi8vcmVjaX
BpZW50LmV4YW1wbGUuY29tIiwibm9uY2UiOiIxb3o1NXQ3TXNObVlGLUREYmlKLUY3cTI
tWENJc3dRU3MtTXk1V0ZwMnJZIn0",
"issuer": "eyJhbGciOiJNQUMtSDI1NiIsInR5cCI6IkpQVCIsImlzcyI6Imh0dHBz
Oi8vaXNzdWVyLmV4YW1wbGUiLCJjbGFpbXMiOlsiaWF0IiwiZXhwIiwiZmFtaWx5X25hb
WUiLCJnaXZlbl9uYW1lIiwiZW1haWwiLCJhZGRyZXNzIiwiYWdlX292ZXJfMjEiXSwicH
Jlc2VudGF0aW9uX2tleSI6eyJrdHkiOiJFQyIsImNydiI6IlAtMjU2IiwidXNlIjoic2l
nbiIsIngiOiJ0R2lmZ2xqOTQ1TW14ckF2UEc1Z0czcW5wUmFST0k4Y2JYLWhELU5QNTZF
IiwieSI6InNLOXV5Tzh4LVprbE1kTXI0U2k0ZWZPZ2M0RUl6U0J6ck4zOHpFTkExV1Eif
X0",
"payloads": [
"MTcxNDUyMTYwMA",
"MTcxNzE5OTk5OQ",
"IkRvZSI",
"IkpheSI",
null,
null,
null
],
"proof": [
"oYu2l2ezvYtrY7dKisbNWSUGlKNhwOp3StAnNJetQu4oscuJFGGuxMwI7k7bTwKo
ZwK_K5Mv8WP3GOsx0zmZWQ",
"b2F3U2oZ29fnxokfZpdfk8oJZVv6aYVZptq8l-9RJ2ypeZNjENMDQlPxWQRMkzU8
zy-JCQ6XaSrWl0HPa2fD9w",
"eNfsgemstMwHlIF0VyLHnPhezehniBqQ5_YA5ceb4y8",
"26hywboboVLNaB2Msj7gvSGpyhn9e_qv_DfK37Fr0G8",
"9GM9wTy56XMB38wZGHlYGA9yVmHZ1zswTU1fhxMti88",
"S8kVw7p7WoymaNMxkLFfRxJ4Hu6S4Du-C2Xln8tXabw",
"XmB-WYWx9-2RmMAXYw1QueXyzOFb1Pw0_TjRigfbb4M",
"lRRFh83TgTd8eYq2fQ7IrnGqBaYEJSc_xAhq63KzZkk",
"OYM9ZpgAv65pLgATwXk_qSW34tp-RabagVifmtELC7A"
]
}
The same JWP in compact serialization:¶
eyJhbGciOiJNQUMtSDI1NiIsImF1ZCI6Imh0dHBzOi8vcmVjaXBpZW50LmV4YW1wbGUuY 29tIiwibm9uY2UiOiIxb3o1NXQ3TXNObVlGLUREYmlKLUY3cTItWENJc3dRU3MtTXk1V0 ZwMnJZIn0.eyJhbGciOiJNQUMtSDI1NiIsInR5cCI6IkpQVCIsImlzcyI6Imh0dHBzOi8 vaXNzdWVyLmV4YW1wbGUiLCJjbGFpbXMiOlsiaWF0IiwiZXhwIiwiZmFtaWx5X25hbWUi LCJnaXZlbl9uYW1lIiwiZW1haWwiLCJhZGRyZXNzIiwiYWdlX292ZXJfMjEiXSwicHJlc 2VudGF0aW9uX2tleSI6eyJrdHkiOiJFQyIsImNydiI6IlAtMjU2IiwidXNlIjoic2lnbi IsIngiOiJ0R2lmZ2xqOTQ1TW14ckF2UEc1Z0czcW5wUmFST0k4Y2JYLWhELU5QNTZFIiw ieSI6InNLOXV5Tzh4LVprbE1kTXI0U2k0ZWZPZ2M0RUl6U0J6ck4zOHpFTkExV1EifX0. MTcxNDUyMTYwMA~MTcxNzE5OTk5OQ~IkRvZSI~IkpheSI~~~.oYu2l2ezvYtrY7dKisbN WSUGlKNhwOp3StAnNJetQu4oscuJFGGuxMwI7k7bTwKoZwK_K5Mv8WP3GOsx0zmZWQ~b2 F3U2oZ29fnxokfZpdfk8oJZVv6aYVZptq8l-9RJ2ypeZNjENMDQlPxWQRMkzU8zy-JCQ6 XaSrWl0HPa2fD9w~eNfsgemstMwHlIF0VyLHnPhezehniBqQ5_YA5ceb4y8~26hywbobo VLNaB2Msj7gvSGpyhn9e_qv_DfK37Fr0G8~9GM9wTy56XMB38wZGHlYGA9yVmHZ1zswTU 1fhxMti88~S8kVw7p7WoymaNMxkLFfRxJ4Hu6S4Du-C2Xln8tXabw~XmB-WYWx9-2RmMA XYw1QueXyzOFb1Pw0_TjRigfbb4M~lRRFh83TgTd8eYq2fQ7IrnGqBaYEJSc_xAhq63Kz Zkk~OYM9ZpgAv65pLgATwXk_qSW34tp-RabagVifmtELC7A
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 ]]¶
-latest¶
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 algorith musage under these definitions.¶
-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¶