Trust Evidence
Trust evidence comprises artifacts and attestations that support signals and assertions with verifiable provenance.
Evidence in the trust stack
Evidence MAY exist independently until linked to a signal or assertion.
Evidence types
| Type | Description | Typical attestor |
|---|---|---|
document | ID, payslip, utility bill, business registration | Verifier or subject |
endorsement | Peer or institutional vouch | Subject or institution |
registry_match | Government or commercial registry hit | Registry connector |
badge | Credential or certification marker | Accrediting body |
third_party_report | Screening or bureau supplement | External provider |
Evidence record
{
"evidence_id": "evd_3f8a1c2b",
"evidence_type": "document",
"uri": "https://vault.example/evidence/evd_3f8a1c2b",
"hash": "sha256:9b1c...",
"attestor_id": "ver_gov_id",
"attested_at": "2026-05-10T08:00:00Z",
"metadata": {
"document_class": "national_id",
"verification_method": "ocr_plus_manual"
}
}
Integrity controls
- Content SHOULD be stored in tamper-evident object storage.
hashMUST be computed at ingest for document types.- Access to evidence URIs MUST require entitled credentials; public lookups MUST NOT expose raw document URIs.
Verification levels
| Level | Meaning |
|---|---|
self_attested | Subject-provided without independent check |
partner_attested | Producer confirms from operational data |
verifier_attested | Independent verifier confirms |
registry_confirmed | Authoritative registry match |
Higher verification levels increase signal weight caps in intelligence derivation.
Chain of custody
Evidence chains SHOULD record:
- Upload or capture timestamp
- Verification steps applied
- Operator or system identity performing validation
- Linkage to resulting signals
Chains support audit requests and dispute resolution.
Retention
Evidence retention follows governance policy:
- Identity documents may have longer retention where KYC law requires.
- Superseded evidence SHOULD be archived, not deleted, until dispute window closes.
- Erasure requests MUST remove or irreversibly anonymize evidence linked to erased subjects.