@algovoi/pef

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algovoi-pef

Payment Evidence Frame (PEF) v1 -- a canonical wrapper format for AlgoVoi payment-lifecycle receipts. Each frame carries a byte-deterministic frame_id (SHA-256 of the JCS-canonical preimage) and an optional detached RFC 9421 signature field.

Normative spec: draft-hopley-x402-payment-evidence-frame-00 (IETF I-D, published 2026-05-30).
Canonicalisation pin: urn:x402:canonicalisation:jcs-rfc8785-v1.

Install

pip install algovoi-pef          # Python
npm install @algovoi/pef         # TypeScript / JavaScript

Quick start

from algovoi_pef import build_pef, verify_pef

# Wrap a compliance receipt in a PEF frame
frame = build_pef(
    claim_type="payment_admission",
    receipt={
        "canon_version": "urn:x402:canonicalisation:jcs-rfc8785-v1",
        "jurisdiction_flags": ["EU", "UK"],
        "payer_ref": "sha256:abc123...",
        "prev_hash": None,
        "screen_provider_did": "did:web:api.algovoi.co.uk",
        "screen_result": "ALLOW",
        "screen_timestamp_ms": 1748534600000,
    },
    frame_provider_did="did:web:api.algovoi.co.uk",
    frame_timestamp_ms=1748534600000,
)

result = verify_pef(frame)
assert result["valid"]
print(frame["frame_id"])
# sha256:09929082c83d5006f61f06bb12eb58cc2c21acebd70a31bca3cb26169c11b6bf

import { buildPef, verifyPef } from "@algovoi/pef";

const frame = buildPef({
  claim_type: "payment_settlement",
  receipt: {
    canon_version: "urn:x402:canonicalisation:jcs-rfc8785-v1",
    settled_payment_ref: "sha256:abc123...",
    settlement_chain: "ethereum:84532",
    settlement_provider_did: "did:web:api.algovoi.co.uk",
    settlement_result: "SETTLED",
    settlement_timestamp_ms: 1748534700000,
  },
  frame_provider_did: "did:web:api.algovoi.co.uk",
  frame_timestamp_ms: 1748534700000,
});

const result = verifyPef(frame);
console.log(result.valid);   // true
console.log(frame.frame_id); // sha256:...

Claim types

PEF defines five claim types, each mapping to an IETF I-D-anchored receipt format:

claim_type	receipt_format	IETF I-D	Platform source
payment_admission	compliance-receipt-v1	draft-hopley-x402-compliance-receipt	/compliance/screen
payment_settlement	settlement-attestation-v1	draft-hopley-x402-settlement-attestation	/checkout/{t}/verify
payment_cancellation	cancellation-receipt-v1	draft-hopley-x402-cancellation-receipt	mandate cancel endpoints
payment_refund	refund-receipt-v1	draft-hopley-x402-refund-receipt	refund endpoints
composite_verdict	composite-trust-query-v1	draft-hopley-x402-composite-trust-query	/compliance/trust-query

Frame structure

{
  "canon_version":      "urn:x402:canonicalisation:jcs-rfc8785-v1",
  "claim_type":         "payment_admission",
  "frame_id":           "sha256:<64-hex-chars>",
  "frame_provider_did": "did:web:api.algovoi.co.uk",
  "frame_timestamp_ms": 1748534600000,
  "pef_version":        "1",
  "receipt":            { "..." : "..." },
  "receipt_format":     "compliance-receipt-v1",
  "receipt_hash":       "sha256:<64-hex-chars>",
  "signature":          "<RFC 9421 detached JWS -- optional>"
}

frame_id derivation

receipt_hash = "sha256:" + hex(sha256(JCS(receipt)))

preimage = {
  canon_version, claim_type, frame_provider_did,
  frame_timestamp_ms, pef_version, receipt,
  receipt_format, receipt_hash
}

frame_id = "sha256:" + hex(sha256(JCS(preimage)))

signature is appended after frame_id is set and is excluded from both hash inputs. Signing the frame_id (rather than the full frame body) keeps the signature stable across re-serialisations.

API

Python

from algovoi_pef import build_pef, verify_pef, pef_frame_id, CLAIM_TYPES

# Build a frame
frame = build_pef(
    claim_type="payment_admission",   # str -- must be in CLAIM_TYPES
    receipt={...},                    # dict
    frame_provider_did="did:...",     # str
    frame_timestamp_ms=1748534600000, # int, epoch-ms
    signature="...",                  # str, optional RFC 9421 JWS
)

# Verify structural integrity (does NOT verify the RFC 9421 signature)
result = verify_pef(frame)
# {"valid": True, "errors": []}

# Re-derive frame_id from an existing frame
fid = pef_frame_id(frame)

# Inspect the closed enum
print(CLAIM_TYPES)
# {"payment_admission": "compliance-receipt-v1", ...}

TypeScript

import {
  buildPef, verifyPef, pefFrameId,
  CLAIM_TYPES, PEF_VERSION, CANON_VERSION,
  type BuildPefOptions, type Pef, type VerifyResult,
} from "@algovoi/pef";

const frame: Pef        = buildPef({ claim_type, receipt, frame_provider_did, frame_timestamp_ms });
const result: VerifyResult = verifyPef(frame);
const fid: string       = pefFrameId(frame);

Platform integration

shared.utils.pef_wrapper in the AlgoVoi gateway provides soft-import helpers so each router can emit PEF-wrapped receipts alongside existing fields:

from shared.utils.pef_wrapper import (
    wrap_compliance_receipt,      # payment_admission
    wrap_settlement_attestation,  # payment_settlement
    wrap_cancellation_receipt,    # payment_cancellation
    wrap_refund_receipt,          # payment_refund
    wrap_trust_query_response,    # composite_verdict
)

# compliance_gate.py -- returns None gracefully if algovoi-pef not installed
pef_frame = wrap_compliance_receipt(
    compliance_receipt_dict,
    screen_timestamp_ms=screen_ts,
)

All wrappers use pef_or_none() -- they return None during a rolling deploy before algovoi-pef is added to the platform requirements, so existing API responses are unaffected.

Cross-implementation validation

frame_id derivation has been independently validated across eight JCS implementations in eight programming languages -- 64/64 byte-for-byte agreements across all five claim types (both receipt_hash and frame_id layers per vector):

Language	Runtime	JCS library	Author
Python	CPython 3.12	rfc8785 0.1.4	Trail of Bits
JavaScript	Node.js v24	canonicalize 1.0.8	Samuel Erdtman
Ruby	Ruby 3.4	json-canonicalization 1.0.0	RubyGems community
PHP	PHP 8.4	inline pure-stdlib JCS	AlgoVoi
Go	Go 1.26	gowebpki/jcs v1.0.1	Web PKI Working Group
Rust	Rust 1.95	serde_jcs 0.2.0	l1h3r
Java	JDK 17	erdtman/java-json-canonicalization 1.1	Anders Rundgren (RFC 8785 author) + Samuel Erdtman
.NET	.NET 9	Baqhub.Packages.JsonCanonicalization 1.0.1	Baqhub

Full attestation record and reproducible runner harnesses: _attestations/2026-05-30-8-impl-pef-v1.md in chopmob-cloud/algovoi-jcs-conformance-vectors.

The same corpus now has 576/576 cumulative byte-for-byte agreements across eight vector sets covering the full AlgoVoi agentic-payment receipt stack (admission, settlement, cancellation, refund, composite verdict, PEF).

Tests

# Unit tests (24 tests)
python -m pytest tests/test_pef.py -v

# Integration smoke tests -- platform-realistic receipt shapes + JS parity (32 tests)
python -m pytest tests/test_smoke_pef_platform.py -v

# Full suite (56 tests)
python -m pytest tests/ -v

# Live API integration test (requires network access to api.algovoi.co.uk)
python -m pytest tests/test_smoke_pef_platform.py -v -m live

# TypeScript tests (20 tests)
npm run build && npm test

Specification

• Normative spec: draft-hopley-x402-payment-evidence-frame-00 (IETF I-D, published 2026-05-30)
• Canonicalisation pin: draft-hopley-x402-canonicalisation-jcs-v1
• Receipt format I-Ds:
  • draft-hopley-x402-compliance-receipt
  • draft-hopley-x402-settlement-attestation
  • draft-hopley-x402-cancellation-receipt
  • draft-hopley-x402-refund-receipt
  • draft-hopley-x402-composite-trust-query
• Upstream x402 PRs: #2493 / #2494 / #2495 / #2524 / #2525
• Conformance vectors: pef_v1 in chopmob-cloud/algovoi-jcs-conformance-vectors

Acknowledgments

Cross-implementation validation is possible because of the independent JCS libraries listed in the matrix above. AlgoVoi acknowledges with thanks: Trail of Bits (rfc8785), Samuel Erdtman (canonicalize and java-json-canonicalization), Anders Rundgren (RFC 8785 author, Java implementation), Web PKI Working Group (gowebpki/jcs), l1h3r (serde_jcs), Baqhub (Baqhub.Packages.JsonCanonicalization), and the RubyGems community (json-canonicalization).

Licence

Apache 2.0. See LICENSE.

Author

AlgoVoi (Christopher Hopley, chopmob-cloud)

Attribution

This package is Apache-2.0. Use it freely and build whatever you are building on top of it. The only ask is the one the licence already makes: keep the NOTICE, and name who authored the substrate. To attribute it in your own product, add this to your NOTICE file:

This product includes the AlgoVoi substrate,
authored by Christopher Hopley / AlgoVoi (chopmob-cloud), Apache-2.0.
https://docs.algovoi.co.uk/canonicalisation-substrate

The full invitation is at https://docs.algovoi.co.uk/canonicalisation-substrate#adopt-the-substrate