Portable Audit Pack Rekor Offline Verification Profile

Status: Draft frozen for implementation handoff (2026-02-10).

Required Rekor material in pack

At least one of:

• rekor/tile.tar
• rekor/tiles.bundle

And manifest references:

• rekor.log_id
• rekor.api_version (2)
• rekor.tile_refs[]
• rekor.root_hash

Offline verification flow

1. Validate manifest signature and manifest file inventory/digests.
2. Load bundled tile material referenced by rekor.tile_refs[].
3. Reconstruct inclusion proof path for covered digests.
4. Validate Merkle root equals rekor.root_hash.
5. Validate checkpoint key material from verifiers.rekor_pub when present.
6. Fail closed on any missing tile/proof/checkpoint dependency.

Stable failure codes

• ERR_REKOR_TILE_MISSING
• ERR_REKOR_TILE_DIGEST_MISMATCH
• ERR_REKOR_PROOF_INVALID
• ERR_REKOR_CHECKPOINT_INVALID
• ERR_REKOR_ROOT_MISMATCH
• ERR_REKOR_REFERENCE_UNCOVERED

Tamper test requirements

• Corrupt one tile byte -> ERR_REKOR_TILE_DIGEST_MISMATCH.
• Modify inclusion path node -> ERR_REKOR_PROOF_INVALID.
• Alter checkpoint signature -> ERR_REKOR_CHECKPOINT_INVALID.
• Alter rekor.root_hash in manifest -> ERR_REKOR_ROOT_MISMATCH.

Compatibility notes

• Existing Rekor receipt contracts remain valid for legacy bundle profiles.
• Portable profile requires deterministic file references under rekor/ in the manifest.