Proofet Atlas 0.1.0 is a release-scoped vocabulary for describing digital identity credential artifacts without conflating their format, declared capabilities, or evaluated assurance. It was published on 25 August 2026 with a known-value cutoff of 24 August 2026.

The release is complete for its declared scope: every characteristic has a stable identifier and a complete value model, and every closed value set is enumerated. It is not a claim that every private, experimental, historical, or future credential technology is known.

Why a faceted taxonomy

A credential is not adequately described by one format label. A W3C Verifiable Credential can use different serializations and securing mechanisms, participate in different exchange protocols, and provide different disclosure or binding capabilities. None of those declarations establishes that a verifier has checked its signature, status, issuer authority, or suitability for a use.

Atlas therefore separates three groups:

Group Question Boundary
A: Intrinsic classification What is the artifact and how is it represented? Observation does not establish authenticity or conformance.
B: Declared mechanisms and context What capabilities or protocol context are visible? Presence does not prove correct construction or achievement.
C: Evaluated assurance What did an analyzer actually check? Every result names its scope, evidence, status, and limitations.

Characteristic map

ID Stable identifier Characteristic
A1 atlas.artifact.kind Artifact kind
A2 atlas.credential.family Credential family
A3 atlas.credential.model_and_profile Model version and credential profiles
A4 atlas.representation.serialization Serialization
A5 atlas.representation.security_envelope Security envelope and representation
A6 atlas.claims.topology Subject and claim topology
A7 atlas.credential.lifecycle Lifecycle and external dependencies
A8 atlas.semantics.definition Schema and semantic definition
A9 atlas.credential.domain Credential domain and intended purpose
B1 atlas.mechanism.cryptography Cryptographic mechanism
B2 atlas.mechanism.selective_disclosure Selective disclosure
B3 atlas.mechanism.key_discovery Key discovery and resolution
B4 atlas.mechanism.holder_binding Holder and presentation binding
B5 atlas.mechanism.credential_status Status and revocation mechanism
B6 atlas.context.exchange_protocol Issuance and presentation protocol
C1 atlas.assurance.decoding Detection and decoding
C2 atlas.assurance.structure Structural analysis
C3 atlas.assurance.conformance Semantic and profile conformance
C4 atlas.assurance.cryptography Cryptographic verification
C5 atlas.assurance.status Credential status and currency
C6 atlas.assurance.trust Issuer authority and trust
C7 atlas.assurance.binding Holder and session binding verification
C8 atlas.assurance.privacy Privacy and disclosure analysis
C9 atlas.assurance.fitness_for_purpose Fitness for purpose

Four value models

Atlas uses the value model appropriate to each characteristic:

  • Closed characteristics enumerate every permitted Atlas value.
  • Registered characteristics list known entries while preserving unmatched external identifiers literally.
  • Structured characteristics report topology, lifecycle, binding, or other observations as typed fields rather than flattening them into labels.
  • Evaluated characteristics record checks that were actually performed.

There is no generic other value. unknown means classification was not possible, while none_detected means a supported inspection completed and found no mechanism. Versions remain separate from identifiers, and published codes never change meaning.

Dimension reference

The tables below are the human-readable reference for this release. Closed sets list every permitted Atlas value. Registered sets list the values known at the release cutoff while allowing exact external identifiers to be retained. Structured dimensions list their fields and controlled sub-values. The registry remains the canonical machine-oriented definition.

A1. Artifact kind

Model: closed · Cardinality: one

Value Meaning
credential Claims issued about one or more subjects.
presentation Credentials or derived claims assembled for a verifier.
disclosure Data revealing a selectively disclosable element.
binding_proof Proof binding a holder, presenter, or transaction.
certificate A public-key and identity binding certificate.
unknown No in-scope artifact kind could be established.

Protocol messages are context for B6, not A1 artifact values.

A2. Credential family

Model: closed · Cardinality: zero or one

Value Meaning
w3c_vc W3C Verifiable Credentials Data Model credential.
sd_jwt_vc IETF SD-JWT-based Verifiable Credential.
iso_mdoc ISO/IEC 18013-5 or ISO/IEC 23220 mobile document.
anoncreds Hyperledger AnonCreds credential or proof family.
x509 ITU-T X.509 and IETF PKIX certificate.
unknown No registered family was established; literal identifiers are retained.

Profiles, products, protocols, and ecosystem names are not credential families.

A3. Model version and credential profiles

Model: structured and registered · Cardinality: one model and zero or more profiles

The model records family, literal version, evidence, and one status:

Model status Meaning
declared The artifact states the version directly.
inferred The version follows from recognized format evidence.
conflicting Available declarations identify incompatible versions.
unknown No model version was established.

Each profile retains its exact identifier and uses these controlled fields:

Field Values and meaning
identifier_kind vct, doctype, type, context, schema, credential_definition, certificate_policy, or unknown: where the identifier was observed.
registry_status registered: a versioned recognition rule matched; unregistered: no rule matched; ambiguous: evidence matched more than one rule.
registry_key Stable Atlas profile code, or null when unregistered.
authority Canonical authority responsible for the profile.

Known profile keys at the cutoff are:

Registry key Meaning
atlas.credential.profile.eudi_pid European Digital Identity Person Identification Data.
atlas.credential.profile.iso_mdl ISO mobile driving licence.
atlas.credential.profile.iso_photo_id ISO photo identification document.
atlas.credential.profile.openbadges 1EdTech Open Badges 3.0.
atlas.credential.profile.learner_credential 1EdTech Comprehensive Learner Record.
atlas.credential.profile.ebsi_vc EBSI Verifiable Credential profile.
atlas.credential.profile.icao_dtc ICAO Digital Travel Credential.

Recognition is classification; C3 separately records profile conformance.

A4. Serialization

Model: closed · Cardinality: one or more layers, outermost to innermost

Value Meaning
json JSON without established JSON-LD processing.
json_ld JSON using the JSON-LD processing model.
cbor Concise Binary Object Representation.
anoncreds_json AnonCreds-specific JSON structure.
asn1_der ASN.1 Distinguished Encoding Rules.
unknown Serialization could not be established.

Base64url and PEM are transfer encodings recorded as evidence. JWS and COSE are security envelopes under A5.

A5. Security envelope and representation

Model: structured and closed · Cardinality: one or more layers

Each layer records a kind, variant, literal media_type, evidence, and a payload relationship: detached (payload external), embedded (payload inside the envelope), enveloping (artifact wraps another artifact), derived (presentation derived from an issued credential), zero_knowledge (proof hides input data), none (no envelope), or unknown.

Kind Variants Meaning
unsecured plain_object No securing envelope was detected.
embedded_proof data_integrity, legacy_linked_data_proof, proof_set, proof_chain Proof material is embedded in the credential object.
jws compact, json, legacy_nested_vc_jwt, direct_payload_vc_jwt, sd_jwt, sd_jwt_kb JOSE signs or carries the payload.
cose sign1, sign, mac0, mac, encrypt0, encrypt, mdoc_issuer_auth, mdoc_device_auth COSE signs, authenticates, or encrypts the payload.
derived_proof bbs_derived, ecdsa_sd_derived Proof was derived for selective disclosure.
zk_credential_proof anoncreds_proof, cl_signature_proof Zero-knowledge credential proof.
unknown literal type or media type retained No registered envelope kind was established.

A6. Subject and claim topology

Model: structured · Cardinality: one

Field Controlled values and meaning
subject_count_status exact: complete count; lower_bound: at least this many; indeterminate: count cannot be established.
subject_identifier_presence all, some, none, or indeterminate: how completely subjects carry identifiers.
holder_subject_relationship same, different, mixed, not_declared, or indeterminate.
bearer_orientation bearer, holder_bound, claims_bound, mixed, or indeterminate.
claim location credential, presentation, disclosure, binding_proof, certificate, or unknown.
claim value_type null, boolean, integer, number, string, binary, object, array, or unknown.
claim cardinality one, zero_or_one, one_or_more, zero_or_more, or unknown.

The structure also records every observed subject identifier, claim path and name, disclosure state, subject relationships, measured depth, and whether the measurement is partial.

A7. Lifecycle and external dependencies

Model: structured · Cardinality: one

Declared start and end times remain available literally and in normalized form.

Window state Meaning
within_declared_time_window Evaluation time is within the declared interval.
before_declared_start Evaluation precedes the declared start.
after_declared_end Evaluation follows the declared end.
indeterminate Available dates do not establish a state.
not_declared No usable time window was declared.

Each dependency retains its identifier and uses:

Field Values
kind status, schema, evidence, terms_of_use, refresh_service, context, verification_method, related_resource, issuer_metadata, trust_registry, unknown
availability embedded, supplied, resolved, not_resolved, resolution_failed, not_applicable
integrity verified, failed, declared_not_checked, not_declared, not_applicable

Availability says whether data was obtained; integrity says whether its authenticity or digest was checked. They are independent.

A8. Schema and semantic definition

Model: structured and closed · Cardinality: zero or more

Value Meaning
json_ld_context JSON-LD context defines term semantics.
json_schema JSON Schema constrains shape or values.
anoncreds_schema AnonCreds schema defines credential attributes.
iso_namespace ISO namespace and document type define mdoc elements.
credential_metadata Issuer or credential configuration metadata supplies definitions.
profile A recognized or literal A3 profile supplies constraints.
proprietary A private identifier or authority supplies definitions.
none_detected Supported inspection found no definition mechanism.
unknown A declaration was observed but not recognized.

Processing history uses declared, resolved, integrity_checked, applied, failed, and not_checked; observing a definition never implies it was applied.

A9. Credential domain and intended purpose

Model: structured and closed · Cardinality: zero or more

Value Meaning
identity General identity or identifying attributes.
education Education, qualification, or learning achievement.
employment Employment status, role, or work history.
professional_licensing Regulated professional licence or entitlement.
authorization Permission, delegation, access, or capability.
health Health status, care, or clinical information.
finance Financial identity, account, transaction, or eligibility.
membership Membership or affiliation.
compliance Regulatory, audit, or policy compliance.
device Device identity, state, or attestation.
supply_chain Product provenance or supply-chain state.
travel Travel document or border-crossing use.
residency Residence, address, or residency status.
age Age or age-threshold assertion.
unknown Domain was not established.

Each observation reports basis (declared, context_supplied, inferred, or unknown), confidence, evidence, and optional literal purpose. Domain does not establish C9 fitness for purpose.

B1. Cryptographic mechanism

Model: structured and registered · Cardinality: zero or more

Field Values and meaning
operation signature, mac, commitment, zero_knowledge_proof, key_agreement, encryption, digest, or unknown: the cryptographic operation represented.
container data_integrity, jws, cose, x509, anoncreds, mdoc, or unknown: where the mechanism is carried.
registry_status registered: recognized value; unregistered: literal not registered; ambiguous: evidence does not select one value.

Items also retain literal proof type, algorithm, cryptosuite, verification method, transformation, and digest identifiers. Registered Data Integrity cryptosuites are eddsa-rdfc-2022, eddsa-jcs-2022, ecdsa-rdfc-2019, ecdsa-jcs-2019, ecdsa-sd-2023, and bbs-2023. Registered proof types include DataIntegrityProof and Ed25519Signature2020. JOSE, COSE, and X.509 values remain exact external identifiers rather than copied closed enums.

B2. Selective disclosure

Model: structured and closed · Cardinality: one

Field Values and meaning
capability present, absent, indeterminate, not_applicable.
granularity claim, nested_claim, object, array_element, namespace, predicate, or unknown: smallest selectable unit.
current_disclosure full, selective, none, indeterminate, or not_applicable: what this artifact reveals.
commitments present, absent, indeterminate, or not_applicable: whether hidden values remain committed.
unlinkability claimed, not_claimed, conditional, indeterminate, or not_applicable.
Mechanism Meaning
sd_jwt_salted_hash Salted-hash SD-JWT disclosures.
data_integrity_bbs_derived BBS-derived Data Integrity proof.
data_integrity_ecdsa_sd_derived ECDSA-SD-derived Data Integrity proof.
mdoc_issuer_signed_item Selection of issuer-signed mdoc elements.
anoncreds_attribute_reveal Selective reveal of AnonCreds attributes.
anoncreds_predicate_proof AnonCreds predicate proved without revealing its input.
atomic_credential Whole credential is the minimum disclosure unit.
unknown Mechanism could not be classified; literal evidence is retained.

Disclosed paths and measurable undisclosed counts are recorded separately.

B3. Key discovery and resolution

Model: structured and registered · Cardinality: zero or more

Method Meaning
did_url Verification method identified by a DID URL.
controlled_identifier_document Controlled Identifier Document supplies material.
jwk JSON Web Key embedded or supplied directly.
jwks JSON Web Key Set lookup.
x509_embedded Certificate embedded in the artifact.
x509_url Certificate retrieved from a URL.
x509_pki PKIX path-building or trust-store discovery.
cose_key COSE key material.
anoncreds_credential_definition AnonCreds credential definition.
trusted_registry Configured trusted registry lookup.
local_key Locally configured verification material.
unknown Discovery method was not classified.

Material format is jwk, multikey, cose_key, x509, anoncreds_credential_definition, or unknown. Resolution status is not_attempted, resolved, not_found, failed, blocked, or not_applicable. Resolution locates candidate material; it does not establish authorization or trust.

B4. Holder and presentation binding

Model: structured and closed · Cardinality: one

Every binding property independently reports declared, not_declared, indeterminate, or not_applicable.

Property Registered mechanisms
Credential binding confirmation_key, subject_key, device_key, link_secret, claims_binding, biometric_binding, bearer, unknown
Proof of possession kb_jwt, vp_data_integrity_proof, vp_jws, mdoc_device_auth, anoncreds_proof, issuance_key_proof, unknown
Presentation binding credential_digest, disclosure_digest, derived_proof, session_transcript, presentation_proof, unknown
Audience binding aud_claim, domain, client_id, origin, session_transcript, unknown
Challenge binding nonce_claim, challenge, session_transcript, unknown
Freshness issued_at, not_before, expiration, nonce, one_time_use, transaction_state, unknown

The property names state what is bound; the mechanism states how. Detection is not C7 verification.

B5. Status and revocation

Model: structured and registered · Cardinality: zero or more

Value Meaning
bitstring_status_list W3C Bitstring Status List.
status_list_2021 W3C StatusList2021.
token_status_list IETF Token Status List.
anoncreds_revocation_registry AnonCreds accumulator revocation registry.
x509_crl X.509 Certificate Revocation List.
x509_ocsp Online Certificate Status Protocol.
online_issuer_check Issuer-specific online status endpoint.
short_lived_only Profile relies explicitly on short credential lifetime.
none_detected Supported inspection found no mechanism.
unknown Status declaration was not recognized.

Purpose is revocation, suspension, message, unknown, or a retained literal extension. Evaluation status is not_checked, good, revoked, suspended, invalid, indeterminate, or not_applicable.

B6. Issuance and presentation protocol context

Model: structured and registered · Cardinality: zero or more

Value Meaning and known stages
openid4vci OpenID4VCI: offer, authorization, token, credential request/response, deferred, notification.
openid4vp OpenID4VP: authorization request, presentation request/response, Digital Credentials API.
presentation_exchange DIF presentation definition or submission.
didcomm_aries DIDComm/Aries issue-credential or present-proof exchange.
iso_mdoc_proximity Device retrieval, engagement, or proximity session.
iso_mdoc_online Server retrieval, OpenID4VP, or Digital Credentials API.
chapi Credential Handler API store or get operation.
digital_credentials_api Browser Digital Credentials API get or create operation.
proprietary Non-standard protocol; literal identifier is required.
unknown Protocol was not classified; literal evidence is retained.

Basis is enclosing_message, endpoint, caller_supplied, or inferred. A bare credential does not establish exchange history.

Assurance value model

All C dimensions use the same evaluated contract. They do not contain static classification values; they contain results from checks that actually ran.

Status Meaning
pass The precisely scoped check ran and passed.
fail The check ran and its rejection condition was met.
warning The check ran and found a bounded concern that is not a definitive failure.
not_checked The operation was not performed.
not_applicable The operation does not apply to this artifact or decision.

Every result also includes a stable check id, characteristic, precise scope, versioned ruleset or null, evidence, detail, limitations, and evaluation time. The registered subjects below describe what a check can evaluate; they do not imply that a particular analyzer implements every subject.

C1. Detection and decoding

artifact_detection identifies the artifact; serialization_decoding parses its encoding; envelope_decoding opens its security container; payload_extraction obtains the protected content; and disclosure_decoding reconstructs disclosed elements.

C2. Structural analysis

required_fields checks presence; value_shapes checks data forms; cardinality checks counts; date_syntax and date_ordering check temporal structure; envelope_payload_consistency compares wrapper and payload; and extension_shape checks extension structures.

C3. Semantic and profile conformance

Check subjects are data_model, context, vocabulary, schema, credential_profile, media_type, algorithm_constraints, and normative_rules. A result must identify the exact specification and version used as its ruleset.

C4. Cryptographic verification

Check subjects are signature, mac, disclosure_digest, derived_proof, zero_knowledge_proof, key_authorization, and certificate_path. Recognizing an algorithm under B1 is not a C4 result.

C5. Credential status and currency

Check subjects are time_window, revocation, suspension, status_integrity, status_freshness, certificate_status, and lifecycle_policy. A time-window pass does not imply a revocation pass.

C6. Issuer authority and trust

Check subjects are issuer_identity, issuer_authority, trust_anchor, trust_registry, governance, accreditation, and authorization_chain. Signature validity alone does not establish issuer authority.

C7. Holder and session binding verification

Check subjects are credential_binding, proof_of_possession, presentation_binding, audience, challenge, freshness, and replay_protection. Declared B4 mechanisms remain unverified until these checks run.

C8. Privacy and disclosure analysis

Check subjects are sensitive_claims, stable_identifiers, disclosure_minimization, correlation, external_tracking, policy_excess, and unlinkability. Privacy findings are scoped to the supplied artifact, policy, and observation context.

C9. Fitness for purpose

C9 applies a named, versioned verifier policy. Its decision outcome is acceptable, rejected, or indeterminate. Outcome is separate from execution status: a correctly executed policy can have status: pass and outcome: rejected. Results also record purpose, jurisdiction, required and missing evidence, and decision rationale.

Classification is not assurance

An algorithm declaration belongs to B1. It does not produce a C4 cryptographic verification result. A status-list reference belongs to B5. It does not show that C5 retrieved, authenticated, and evaluated the current status. Likewise, recognizing a credential profile under A3 does not establish C3 conformance.

This boundary is the central compatibility rule of Atlas: evidence supports only the observation or check that cites it.

Release artifacts

The immutable package contains the conceptual taxonomy, complete registry, release notes, a digest manifest, and JSON Schema Draft 2020-12 contracts for registry entries, classification assertions, assurance results, and release manifests.

The manifest records SHA-256 digests for every payload file. The intended Git tag is atlas-v0.1.0.

Implementation status

Atlas 0.1.0 defines the target information model independently of the current Proofet API. The API currently implements a bounded subset and does not yet emit all 24 characteristics. An API response should claim Atlas 0.1.0 compatibility only after its response contract and behavior have been validated against this release.

Future compatible corrections will use patch releases. Before 1.0.0, minor releases may add, deprecate, or refine characteristics and structured contracts; deprecated codes will not be reused.