Evidence Fabric Overview — Executive Brief

Evidence Fabric Overview

UIAO’s Evidence Fabric is designed to turn runtime telemetry into assessor-ready compliance artifacts with traceable provenance at every step. Instead of a single point-in-time screenshot, it produces a deterministic evidence bundle that can be re-run and independently verified.

Provenance chain (event → claim → OSCAL artifact)

The intended chain is:

  1. Telemetry event capture from adapters and governance controls.
  2. Canonical claim normalization under the provenance envelope defined in 15_ProvenanceProfile.qmd.
  3. Evidence bundling and mapping into OSCAL-native outputs for assessors.

This creates a lineage from source signal to compliance statement, so a 3PAO can trace any finding back to a concrete, hashed source record.

Determinism and reproducibility

Per ADR-006, the fabric is designed for deterministic behavior: no silent drops, append-only writes, ordered records, integrity hashing, and idempotent ingestion. In practice this means same inputs produce the same evidence bundle, enabling byte-reproducible regeneration for reassessment, forensics, and dispute resolution.

Cryptographic anchoring and signing posture

Evidence integrity is anchored with cryptographic hashes in the provenance envelope and bundle-level provenance fields defined by evidence-bundle.schema.json. The schema enforces hash-bearing provenance structures at item and bundle scope, providing the verification substrate for signed, tamper-evident evidence packages.

Evidence outputs available today

UIAO currently emits or assembles the following evidence surfaces:

  • System Security Plan (SSP)
  • POA&M
  • KSI dashboard artifacts
  • Component Definitions

Bundle lifecycle controls (assemble → seal → submit → close) are defined in ADR-016 to support governed handoff to federal assessors.

Maturity and current-state honesty

The event-time capture chain is design-defined but not fully wired in current production flow. UIAO already defines deterministic structure, provenance fields, and bundle lifecycle controls; end-to-end continuous event-time capture remains a target-state capability and is represented here as aspirational.

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