Repro Bundle Profile (SLSA v1 + in-toto + DSSE)

Status

Planned contract (gap-closure track).
Implementation sprint: docs/implplan/SPRINT_20260209_001_DOCS_repro_bundle_gap_closure.md.

Define the minimum reproducibility evidence required for release promotion.
Standardize canonicalization rules so rebuild and verification outcomes are deterministic.
Preserve online and offline parity for transparency verification workflows.

build_provenance.json with SLSA v1 predicate fields:
- builder.id and builder.version
- source binding (invocation and commit)
- materials[] with pinned digests
- canonicalized build command representation
- pinned toolchain digest (@sha256:...)
in_toto.link mapping materials to products with deterministic digests.
DSSE signatures/envelopes for provenance and link payloads.
Transparency evidence:
- Online mode: Rekor entry metadata.
- Offline mode: local checkpoint/tile bundle and verification metadata, including Rekor leaf hash (leafHash), path hashes, and checkpoint root.

Paths and filenames must be Unicode NFC.
JSON payloads must be canonicalized with sorted keys and deterministic encoding.
PURLs/material references must be pinned, digest-backed, and deterministically ordered.
Archive outputs must use deterministic metadata/order:
- fixed timestamps (policy default: zero epoch)
- stable uid/gid and owner names
- fixed mode policy
Line endings must be normalized (policy default: LF).
Build environments must pin deterministic settings:
- LC_ALL=C
- TZ=UTC
- stable source date epoch
Toolchains must be digest-pinned; mutable tags are non-compliant in strict mode.

Verify DSSE signatures with bundled trust roots/keys.
Verify bundled inclusion proof data cryptographically (leaf hash + Merkle path + checkpoint root) without network.
Missing/invalid proof material is fail-closed by default.
If break-glass verification is allowed, it must be explicitly configured and recorded in evidence with machine-readable marker(s).

Promotion must block when any required repro evidence is missing or invalid.
Promotion must block when canonicalization policy fails.
Promotion must block when toolchain digest pinning is absent.
Gate output must include stable rejection codes and references to failed evidence files for replay.

Attestor: strict predicate validation, DSSE handling, Rekor verification (online/offline).
ReleaseOrchestrator: fail-closed promotion gate enforcement and policy simulation.
EvidenceLocker: storage/export contracts for repro-bundle artifacts and offline verification packs.
Provenance: provenance model extensions and deterministic serialization support.
devops: deterministic build/container/pipeline defaults and toolchain pinning.