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Run the standard's adversarial-diff method against its own reference implementation (provenance/joulecontract-diff-v0.6-impl.md): two blind lenses, 28 findings, four guarantee bypasses — case-variant key forgery, the entity-omission Party hole, caller-supplied generator key sets, and reseal-under-any-key — all repaired: - schema: content addresses are canonical (lowercase, digest-width enforced); canonicalizer depth-bounded; non-finite joules rejected at the typed boundary before they can null-collide under addressing. - receipt: independence computed over the effective generator key set (declared ∪ receipt signer ∪ attestation signer); Party requires both entities bound, normalized, unequal; receipt-local validate() honestly caps at JR-2, with the new composed validate_sealed() evaluating the full JR-3/JR-4 ladder over sealed evidence resolution, the office key log, anchor gates, quorum, and loop governance; receipts bind their allowance and EnB to the contract ceiling (residual minting is malformed); claims emit the exact §15 token vocabulary. - seal: verify_offline takes the expected verifier-of-record key — integrity is no longer mistaken for authenticity. - amend: the key log evaluates events chronologically (out-of-order appends cannot resurrect a revoked key); classify takes the named covering amendment, not "any amendment whatsoever". - wire (new crate): the receipt as an in-toto Statement v1 with the JouleContract predicate type in a DSSE envelope, exact PAE, Ed25519. - conformance: shared fixtures, the four rounds' attacks as tests, and a regenerable conformance/v1 vector pack (13 vectors + MANIFEST) whose expected verdicts come from the repaired validators, including both the local JR-2 and composed JR-3 grades and two malformed cases. 64 tests green, clippy zero warnings. READMEs state what is implemented and what is named-but-open (composition, ratchet, recourse bindings). Co-Authored-By: Claude Fable 5 <[email protected]>
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7.3 KiB
Markdown
46 lines
7.3 KiB
Markdown
# JouleContract round four — the implementation diff
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**Target:** not the spec text (rounds 1–3) but the v0.6 reference implementation, `joulecontract-rs`.
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**Lenses (mutually blind):** (1) spec-vs-code fidelity — where the code passes what the spec forbids or silently skips a mandated gate (findings F1–F19); (2) Rust soundness, API misuse, and adversarial inputs — where a malicious caller breaks the library's guarantees (findings R1–R9 + minors).
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**Verdict:** 28 findings; four genuine guarantee bypasses; all blockers and serious findings repaired in the same change that records this document. The standard's law of evolution held one more time: the implementation was forced to apply the spec's own rules to itself.
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---
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## The four bypasses (found, then killed)
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1. **R1 — case-variant key forgery.** `ContentAddress` equality was case-sensitive on the hex string while `of_bytes` emitted lowercase: writing one key as `ABCD…` in the generator set and `abcd…` on the discharge made the *same key* compute as disjoint — fake independence, self-signed meters passing as third-party, self-attestation passing the generator gate. *Fix:* identity is canonical — parse normalizes to lowercase and rejects non-digest-width hex; a case variant is the same address everywhere (schema).
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2. **R2/F2 — the entity-omission Party hole.** `compute_independence` granted `Party` when the *generator* carried no entity binding at all — omitting `generator.entity` (which triggered no demotion) bought the strongest independence level with one self-asserted verifier string. *Fix:* `Party` requires **both** sides bound, normalized (trim + case-fold; round-four R8), and unequal; undecidable floors at `KeyOnly`, never ceilings at `Party`.
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3. **F1 — the caller-supplied generator key set.** §5.1.1 defines the key set; the code took it as a producer-declared field and computed disjointness against it — declaring it empty and signing discharges with the receipt-signer key computed `independent: true`. The §6.2 "computed, never copied" rule was defeated because the *operand* was producer-supplied. *Fix:* validation computes the **effective** set — declared ∪ receipt signer ∪ attestation signer — so under-declaring buys nothing.
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4. **R5 — reseal-under-any-key.** `seal::verify_offline` authenticated the envelope against its *own embedded key*: any forger could reseal any payload under their own key and pass. Integrity without authenticity. *Fix:* the caller supplies the expected verifier-of-record key (from the office key log, as of discharge); a mismatched signer is `WrongSigner` before any other check.
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## The honest restructuring: local vs composed validation
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The deepest fidelity finding (F3/F4/F5) was that `validate` returned **JR-4** from receipt-local evidence while §10 assigns JR-3+ gates the receipt alone cannot witness — quorum, loop governance, independent anchors, sealed-evidence resolution, key-log time coordinates. Worse, the shipped conformance vector canonized the over-grade as a published expected verdict. The repair is architectural, not cosmetic:
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- **`validate` (receipt-local) now caps at JR-2 / `managed`** and says so — it does not pretend to see evidence it cannot.
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- **`validate_sealed` (composed)** takes the evidence bundle, the office key log, the transition interval, and the profile parameters, and evaluates the full ladder: every trust-bearing reference must resolve *within the sealed bundle* (F6); verifier keys are checked against revocation windows as of the start anchor (F8); anchors must be independent and prompt (`timestamp_unanchored` / `timestamp_stale` now producible from validation, F13); quorum is k ≥ 2 distinct party-bound verifier entities, per-obligation at JR-4 (F3); loop governance must be present and generator-independent for JR-3 and for `certified` (F3/F9); an open unamended breach caps Governance (F9).
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- The conformance vector now publishes **both** verdicts — the local JR-2 and the composed JR-3 — so a third-party implementation is tested on the distinction itself (F5).
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## Also repaired
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- **R3** — non-finite/negative joules are malformed (`IllFormedEnergy`), closing the NaN→`null` content-address collision; the canonicalizer is depth-bounded against adversarial nesting.
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- **R7** — the receipt's `joules_allowed` and `enb_ref` now bind to the contract's ceiling (mismatch is malformed, not demoted): residual minting by inflated allowance is dead, and ships as a malformed vector.
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- **R4/F16** — `Verdict::claim()` emits the exact §15 token vocabulary (`metered_unattested`, `qualified:false`, `evidence:external`…), deduplicated, with free-text reasons excluded from the token list.
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- **R6** — `KeyLog::key_set_as_of` evaluates events in chronological order of effective time (revocation outranks addition at the same instant): an out-of-order or backdated append can never resurrect a revoked key.
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- **R9/F7** — `classify` no longer accepts "any amendment whatsoever" or a caller-asserted bool: the caller names the *specific* covering amendment (temporal half enforced mechanically; content coverage stays the verifier of record's judgment, stated in the doc) and the fix-receipt is a content address to be resolved against evidence.
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- **F10** — a stochastic discharge's `re_discharged_by` is verified, not trusted: it must reference a real deterministic, generator-independent, closed entry for the same obligation in this receipt.
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- **F11** — qualification signers are checked against the **tier operator's** keys (new field), not merely the discharging verifier's.
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- **F12** — the meter binding is validity-windowed; `ModelBased` without a sealed anchor demotes to `Unaccounted`.
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- **F4** — the receipt now carries `execution`, `register_pin`, `evidence` (bundle address; absent serializes `evidence:external`), `energy_anchor`, and optional `grid_mix`; the interval is supplied to composed validation by the amend seam.
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- **F17** — JR-2 tests the *frame entry's* independence, not the global weakest.
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## Named, not closed (the honest ledger)
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- **Composition (§3.3) and the ratchet (§5.3)** are not implemented; `component_unattributed` is not yet producible. No code claims otherwise.
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- **`recourse_undeclared` and `target_self_assigned`** have no carrying fields yet (no recourse-regime binding on verifier credentials; no sector-equivalence claim on the contract).
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- **`evidence_lost` vs `unresolvable`** — the distinction exists in `seal::evidence_state`, but composed validation currently treats a missing object as `unresolvable`; modeling the issuance-time validation record is follow-on work.
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- **Cryptographic agility (§3.1)** is a one-variant enum with no cross-digest re-anchoring amendment record yet.
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- **`residual` carried vs computed** — the spec's §5.1 lists it as a receipt field; the implementation derives it (`Receipt::residual()`) because a stored copy could lie. Candidate v0.7 spec amendment: declare the residual derived.
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- **F18-adjacent** — the in-toto digest map uses the ecosystem's bare `sha256` name at the edge while the core stays algorithm-prefixed; stated in `joulecontract-wire`.
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*Workspace after repairs: 64 tests green, clippy zero warnings, 13 regenerated vectors whose expected verdicts come from the repaired validators. Prior rounds: `joulecontract-diff-v0.3-global.md`, `joulecontract-diff-v0.4-self.md`, `joulecontract-diff-v0.5-self.md`.*
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