nenrin-verify (Python)

Recompute NENRIN evidence yourself, offline, in your own Python process. The Python twin of the npm package nenrin-verify and of the TSUGI recovery-chain verifier tsugi_verify.mjs: same input, same report (the limits are listed under "Where the claim stops").

pip install nenrin-verify
nenrin-verify --selftest          # 31/31 frozen bundles and 98/98 frozen TSUGI chains match the JavaScript
nenrin-verify bundle.json         # the provenance report; exit 0 accepted, 1 refused
tsugi-verify chain.json --operator-key <b64>   # a TSUGI recovery chain, printed as node tsugi_verify.mjs prints it

import json, nenrin_verify as nv

bundle = nv.js_loads(open("bundle.json", "rb").read())   # parsed the way JSON.parse parses it
report = nv.verify_bundle(bundle)             # did:key resolution, no network, no clock
print(report["verdict"], report["does_not_establish"])
print(nv.report_json(report))                 # JSON text as the JavaScript CLI prints it (not json.dumps)
print(nv.report_sha256(report))               # compare with the JavaScript run, byte for byte

One dependency, cryptography, for Ed25519. Nothing here opens a socket, except tsugi-verify --fetch-operator-key <origin>, which fetches the operator key from the origin you name.

What it verifies

How "same report" is checked

The JavaScript file is the reference. The port reads it line for line, and every place where Python and JavaScript disagree by default (x or y on {}, == on True and 1, Date.parse accepting February 31st, Node's lenient base64, an own __proto__ key that Object.assign turns into a prototype, the order V8's sort gives values a numeric comparator cannot order, new URL(s).host) goes through src/nenrin_verify/_js.py and src/nenrin_verify/_url.py, so the differences can be read in one place.

• Frozen. 31 bundles signed with keys derived from a public phrase, covering accepted graphs, refusals of every layer, witness disagreement, provider equivocation, action bindings, non-ASCII and escapes, and the date edge cases. For each, the report, the consume_evidence projection and the CLI output are byte-identical to the JavaScript's. They ship in the package; nenrin-verify --selftest re-runs them on your machine.
• Live. Every path of every frozen bundle is broken in about twenty ways (deleted, nulled, retyped, shortened, reordered, timestamps and sequence numbers bent, own __proto__ keys added, the whole bundle replaced by an array or null), 27,062 inputs in all. Each is run through the JavaScript verifier and through this port. Pass means both threw, or both returned the same report and projection. 0 differ.
• Semantics. The helpers in _js.py against Node directly: number text, Date.parse, Buffer base64, string escaping and mixed-type sorting, several thousand random values each.
• Agreement. The packaged agreement verifier returns every one of the 5,286 frozen reports in agreement-v0/agreement_vectors_v1.json, the file the JavaScript verifier is scored against.
• Unchanged. VENDORED.json pins the sha256 of the agreement files and their sources; a copy that drifts fails.
• TSUGI, frozen. 98 cases: the repository's three real chains (incident 2 with the real operator signature, 12 records; the 7-record incident of the same week; that incident re-verified by a random draw of witnesses), under the command lines that matter, and edits of them that reach every one of the 69 refusal codes tsugi_verify.mjs has, plus the five inputs on which the JavaScript itself throws. Edited chains are re-sealed so an edit meets the rule it targets, not only a hash mismatch. For each, node tsugi_verify.mjs was run and its stdout and exit code frozen; they ship in the package and nenrin-verify --selftest re-runs them.
• TSUGI, live. Every path of the real chains and of the witness pool is edited in about twenty ways, raw and re-sealed: 29,326 inputs with the frozen cases. Each is run through tsugi_verify.mjs and through this port. 0 differ; 3 edits put a non-ASCII host in an endpoint, and there the port raises NotReproduced instead of answering (see below).
• TSUGI semantics. new URL(s).host, toLowerCase, Buffer.from on any JSON value and string conversion of any JSON value, against Node directly, several thousand inputs each.

report_sha256(report) is the sha256 of the report with keys sorted by UTF-16 code unit at every depth, no whitespace, strings and numbers as JSON.stringify writes them. The JavaScript side of the same hash is tests/parity/js_canon.mjs (twelve lines).

Where the claim stops

• Stack depth. A document nested deep enough to exhaust a runtime's stack has no report in that runtime, and Node and Python run out at different depths (Node threw at 3,000 nested arrays inside a signed field, Python's default limit is 1,000). Real bundles are a few levels deep.
• Sixty-four or more non-numeric hop.seq values in one bundle. The order of those keys is V8's merge sort over a comparator that cannot order them; the port reproduces V8 for up to 63 keys and raises above that instead of guessing.
• Where the JavaScript throws, the port raises; the CLI then prints no report and exits 2 (Node exits 1 on an uncaught throw).
• TSUGI: hosts that need UTS #46. The verifier compares and prints URL hosts as WHATWG new URL(s).host gives them. The port follows the standard for ASCII hosts, IPv4 in every form the standard reads, ports and userinfo, and raises NotReproduced (no report, exit 2) for a host that is not ASCII after percent-decoding or has an xn-- label, an IPv6 literal, or a file: URL. Lowercasing a code point this Python's Unicode tables do not assign raises the same way (Node 24 knows Unicode 16; Python 3.9 knows 13).
• TSUGI: one refusal text depends on the Node release. For an Ed25519 public key that is not 32 bytes, Node 24 writes "Invalid keyData" and Node 22 "Ed25519 raw keys must be exactly 32-bytes". The port writes Node 24's (tsugi.KEY_LENGTH_MESSAGE); the tests compare Node 22's output after that one substitution.
• TSUGI: --fetch-operator-key makes the same request as the JavaScript (GET <origin>/keys/operator.json, 404 read as no key) but is not part of the comparison, which runs offline.

What it does not establish

What every report says itself, accepted or refused: a signature proves who asserted, not that the assertion is true; E1 compares a provider's signed claim to a caller's signed authorization and has no side-effect oracle; R1 proves a witness is structurally distinct from the parties, not unaffiliated with them. There is no score and no allow or deny anywhere in this package. The decision belongs to whoever reads the evidence.

Not in this release: the MUSUBI contract spine. It comes in when it can carry the same guarantee as the three verifiers above: the same report as its JavaScript twin, checked case by case.

Reproduce

cd workers/hs-ledger/nenrin/sdk-python
pip install -e . pytest
node tests/fixtures/make_fixtures.mjs --check   # the frozen fixtures re-create byte for byte
python tests/fixtures/make_tsugi_cases.py --check   # the frozen TSUGI cases and their JavaScript output re-create
python tools/vendor.py --check                  # the agreement copies are their sources
pytest tests -q -s                              # frozen, live differential, agreement, TSUGI

Published from GitHub Actions with PyPI Trusted Publishing and attestations (.github/workflows/pypi-publish-nenrin-verify.yml); the parity suite runs on every change to this directory, to the JavaScript SDK, to the agreement verifier and to the TSUGI chains (.github/workflows/nenrin-verify-py.yml).

MIT. The HORIZONs Co., Ltd.