softwarefabrik.io
Offline verifier · 1.0.0

Check the evidence without trusting the factory.

This tool checks an audit export of the factory without access to the factory: whether entries were changed, left out or cut off at the end, which policy applied to a run, and whether everything is signed with a trusted key.

JDK only, no dependencies about 1,000 lines of Java reproducible build

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Version 1.0.0, for exports from schema 2.0 (factory v0.32.0 and later). Requires JDK 25 or newer.

The tool deliberately does not come from the factory being audited: you don't obtain an audit tool from the audited party. The build is reproducible — two builds from the same source yield a byte-identical JAR. To rebuild: unpack the source, run mvn package with JDK 25 on a Linux file system (on NTFS drives under WSL only the file permissions of the JAR entries differ, not the content).

What you need

  1. The export — in the factory under Audit export as JSON, per project or run.
  2. The fingerprint of the signing key — in the factory under Attestation → trust anchor. Have it confirmed via a second channel (letter, ticket, signed e-mail): whoever forges entries can also replace the key in the export.
  3. The verifier from this page.
java -jar softwarefabrik-verifier-1.0.0.jar audit-export.json --schluessel <fingerprint>
ExitMeaning
0Proven: chain, signatures and run evidence backed by the trusted keys
1Violation: changed, incomplete, signed by an untrusted key or self-contradictory
2No violation, but not everything provable — e.g. without --schluessel
3Usage error

Without --schluessel the check never ends with 0. With --bekannt <seq>:<hash> you pass a previously seen chain state, which must be contained unchanged. (The tool's output is in German.)

What is checked

  1. Keys: fingerprint of every public key against your trusted values.
  2. Entries: recompute the hash from the documented canonical form, verify the Ed25519 signature.
  3. Placeholders: entries of other runs and tenants appear only as hash plus signature — completeness is checkable without disclosing foreign content.
  4. Chaining: gap-free sequence, every entry points to its predecessor. Omission, insertion and reordering are detected.
  5. Head: the chain ends exactly at the signed head — otherwise entries are missing at the end.
  6. Policy: the version applied in the run, content and signature.
  7. Run evidence: which events belong to a run is attested by a signed manifest; each must be a verified entry of that run.

Fields in which the factory judges itself (“intact”, “chain ok”) do not count as evidence.

Limits

  • Integrity is proven from the first exported entry up to the time of export.
  • Someone with database access before the export could delete the newest entries and reset the head. --bekannt with a previously recorded state protects against this.
  • The completeness of the assignment of events to a run is attested by the factory's signature at export time.
  • Agent tool calls are not yet recorded in the chain.

Background and decisions: ADR-0023 “Offline verifier for the audit export”.