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N-PAMP draft-01 — Python quickstart

impl/python is the Python port of the OPEN-protocol reference library for N-PAMP draft-bubblefish-npamp-01: the wire-format and cryptographic primitives. Standard profile only (SHA-256, X25519MLKEM768, Ed25519, AES-256-GCM).

What this port provides

The single module npamp/__init__.py exports:

  • Frame codec — the 36-octet header (magic NPAM, version, flags, type, channel, seq, CRC32C) + payload: Frame.marshal / Frame.unmarshal / Frame.header_prefix, plus crc32c.
  • AES-256-GCM record layer — seal_aes256gcm / open_aes256gcm / derive_nonce, using the 21-octet header prefix as AEAD associated data.
  • HKDF key schedule — hkdf_extract, hkdf_expand, hkdf_expand_label (RFC 8446 §7.1 with the "n-pamp " label prefix), derive_traffic_secret, derive_key_iv.
  • Handshake-binding primitives (binding spec/10) — Transcript (§3), the key-schedule trunk derive_handshake_secret / derive_handshake_traffic_secrets / derive_finished_key (§5), compute_finished / verify_finished (§6.2), and sign_cert_verify / verify_cert_verify (§6.1, Ed25519).
  • Registry code points — channel / frame-type / TLV / KEM / AEAD / signature constants.

(High / Sovereign profiles, ML-KEM-1024, and ML-DSA-87 are out of scope for this open module.)

What this port does NOT provide

  • KEM operations — no X25519MLKEM768 encapsulation/decapsulation; the key-schedule trunk takes the two KEM shared secrets as inputs.
  • A TCP/TLS transport (ALPN n-pamp/2), connection management, or an RPC/MCP client. Those live in a consuming product, which composes primitives like these with its own handshake + transport.

Install

Python ≥ 3.9 with the cryptography package (≥ 42), the port's only dependency:

pip install "cryptography>=42"

Or install the module itself from impl/python: pip install -e .

Run the tests

All commands run from impl/python. The test scripts import the npamp package from the working directory, so set PYTHONPATH=. (this mirrors _conformance-harness/kat-handshake-all-langs.sh):

# bash
PYTHONPATH=. python tests/test_conformance.py       # 4 golden vectors + 5 property tests
PYTHONPATH=. python tests/test_transcript_kat.py    # handshake KATs (spec/10 §3, §5, §6.2, §6.1) —
PYTHONPATH=. python tests/test_key_schedule_kat.py  # three-leg ANCHOR/ORACLE/IMPL against the
PYTHONPATH=. python tests/test_finished_kat.py      # pinned vectors in ../../test-vectors/v1/
PYTHONPATH=. python tests/test_certverify_kat.py

# PowerShell
$env:PYTHONPATH = "."
python tests/test_conformance.py

Each script prints one PASS/FAIL line per check and exits non-zero on any failure. The pinned KAT vectors are SHA-256-checked inside each test (fail-loud on a swapped vector).

Two further checks need corpora that are not included in this open reference repository and are runnable only where those corpora are provided:

  • test/kat_aesgcm_wycheproof.py <aesgcm_kat.tsv> — Project Wycheproof AES-256-GCM verdicts.
  • python npamp_vectors.py — emits the cross-language conformance vectors as JSON for the byte-compare drift gate (_conformance-harness/run-all-langs.sh). The generator itself runs anywhere; only the byte-compare needs the externally-provided vectors.json.

Run the example

examples/secure_record_layer.py composes the key schedule + record layer + frame codec into one send → receive round-trip (a Python mirror of the Go Example_secureRecordLayer):

python examples/secure_record_layer.py

Expected output:

channel=1 seq=0 encrypted=true
recovered: hello over n-pamp

Conformance

The language-agnostic conformance corpus + KAT vectors live in test-vectors/v1/ (frozen in MANIFEST.sha256). This port is one of the handshake-bearing implementations graded by impl/_conformance-harness/kat-handshake-all-langs.sh; the handshake KATs grade it against NIST/RFC anchors, non-circularly.

License

Apache-2.0 — see LICENSE / NOTICE at the repository root.