[HackTuah]

Slice 144: N6 v0.1 verdicts. A defect in bytes a verified signature covers is the signer's act (exit 7). Ed25519 is held to the publisher's rule. A receipt chain's crossing from v3 to v4 is reported.

What changes

• Exit 7 (draft v0.1-r7 sections 9.2 and 9.3). Trinity.N6.Carrier.verify/2 reads the body only after the signature verifies. The first defect met there answers {:error, 7, {verdict, [nonconforming: code]}}:

  • accuse_single_signed_noncanonical for a codec defect (D0 to D18);
  • accuse_single_signed_nonconforming otherwise.

  Judging stops at the first defect, so there is at most one finding. With schemas: the whole body is checked (B1 to B8).

• Receipts. Trinity.Receipts.V4 verifies a row's or checkpoint's carrier before decoding its body. A defect in a signed body was always exit 1 before; it is now exit 7.

  • The in-app verifier, mix trinity.receipts.verify and bin/verify_receipt.exs gain exit 7.
  • The task and the script print finding: nonconforming <code>, then verdict_code: <code> last.

• Ed25519 (r7 section 5.3, decided 2026-10-21).

  • A key must decode strictly, must not be the identity, and [L]A must be the identity (key_invalid).
  • A signature's R must decode strictly and not be of small order, and S must be below L (signature_invalid).
  • These checks run before OpenSSL's equation. OpenSSL 3.0.13 and 3.5.9 accept the identity key with R the identity and S = 0 for every message.

• The crossing (r7 section 3.9). The first v4 row after a v2 or v3 row adds the finding {:crossing, seq}. A v2 or v3 row after a v4 row is refused, {:legacy_after_n6, seq}. Both names are Trinity's until the profile names them.

Evidence

• test/trinity/n6/verdicts_test.exs and test/trinity/receipts/verdicts_test.exs: 8 tests. Copied onto main (54498d5), 0 of 8 pass, each for the reason named in the slice. On this branch, 8 of 8.
• The Ed25519 cases are built by test/support/ed25519_points.ex, an oracle independent of the module under test. It reproduces RFC 8032 test 1's public key from its seed.
• Three new carrier samples in test/fixtures/n6: a format control in a signed body, R the identity, and the identity key. ed25519_no_issuer and ed25519_typ_schema_mismatch now expect exit 7 with one finding.
• test/trinity/n6, test/trinity/receipts, test/trinity/crypto and test/mix: 279 passed.