Software Bill of Materials and Build Provenance

Every deployed artifact carries a complete bill of materials and verifiable build provenance, so what runs on the plant is traceable to reviewed source.

Know exactly what is running

You cannot defend what you cannot enumerate. A Software Bill of Materials (SBOM) lists every component and dependency in an artifact, with versions and hashes. Build provenance (in the SLSA sense) records how that artifact was produced - which source commit, which builder, under what conditions - and signs the attestation. Together they let Kronos confirm that a control binary or ML model corresponds to reviewed, unmodified source before it is admitted to OT.

What the provenance chain asserts

• Source: the exact commit and repository the artifact was built from.
• Build: an isolated, reproducible builder produced it; the build is not attacker-influenced.
• Materials: the SBOM of all inputs, each pinned by hash.
• Signature: the whole attestation is signed with a post-quantum signature for long-term verifiability.

# Admission control: reject artifacts without matching provenance
def admit(artifact):
    prov = artifact.provenance
    if not verify_sig(prov, builder_root):        return DENY
    if prov.source_commit not in approved_commits: return DENY
    if sha384(artifact.bytes) != prov.subject_hash: return DENY
    for dep in artifact.sbom:
        if dep.hash not in allowed_components:      return DENY  # no surprises
    return ADMIT

Feeding runtime trust

The SBOM and provenance are what firmware signing and attestation ultimately vouch for: the signature at boot is only meaningful because the signed thing has a known, reviewed origin. Provenance also enables fast response to a newly disclosed vulnerability - Kronos can query which deployed artifacts include the affected component.

Design status

SBOM generation, provenance attestation, and admission control run in the Kronos build pipeline and against the twin's deployment path. Extending this to every FOAK hardware firmware image is part of the 2027 build-out; the pipeline exists today, the reactor it will gate does not.