Verification

PEAC verification is offline and deterministic. Given a receipt, the issuer's public key, and optionally a policy digest, verification produces the same result every time with no external dependencies.

Zero network calls required

Verification runs entirely locally. The verifier needs only the receipt (a JWS string) and the issuer's public key (Ed25519). No callback to the issuer, no token introspection endpoint, no online dependency.

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Verification checks

The verifier runs a sequence of checks against each receipt. verifyLocal() auto-detects wire version and applies the appropriate checks.

Common checks (both wire formats)

#	Check	Description
1	Signature valid	Ed25519 signature verification against the issuer's public key
2	Algorithm allowed	Algorithm must be EdDSA (no other algorithms accepted)
3	Type header present	typ must be peac-receipt/0.1 or interaction-record+jwt
4	Key ID present	kid must exist in the JWS header
5	Claims well-formed	All required claims present and correctly typed
6	Issued-at valid	iat is a valid Unix timestamp

Wire 0.2 additional checks

#	Check	Description
7	JOSE hardening	Rejects embedded keys (jwk, x5c, x5u, jku), crit, b64: false, zip
8	Issuer canonical	iss must be canonical (https:// or did: only)
9	Kind valid	kind must be evidence or challenge
10	Type grammar	type must be valid reverse-DNS or absolute URI
11	Pillars valid	All pillars must be from the 10-pillar taxonomy, sorted and unique
12	Extension schemas	Known extension groups pass their registered schema validation
13	Occurred-at coherence	occurred_at only allowed on evidence kind
14	Policy binding	Policy digest comparison (3-state: verified, failed, unavailable)

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Basic verification

Pass a receipt JWS string and the issuer's public key. verifyLocal() auto-detects wire version.

verify.ts

import { verifyLocal } from '@peac/protocol';

const result = verifyLocal(receiptJWS, publicKey);

if (result.valid) {
  console.log('Wire version:', result.wireVersion); // '0.1' or '0.2'
  console.log('Claims:', result.claims);
  console.log('Policy binding:', result.policy_binding);

  if (result.wireVersion === '0.2') {
    console.log('Kind:', result.claims.kind);
    console.log('Type:', result.claims.type);
    console.log('Warnings:', result.warnings);
  }
} else {
  console.log('Verification failed:', result.reason);
  console.log('Error code:', result.code);
}

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With policy binding (Wire 0.2)

For Wire 0.2 receipts, provide a policy digest to verify policy binding.

verify-with-policy.ts

import { verifyLocal, computePolicyDigestJcs } from '@peac/protocol';

// Compute digest from your policy document
const policyDigest = await computePolicyDigestJcs(policyDocument);

const result = verifyLocal(receiptJWS, publicKey, {
  policyDigest,
});

if (result.valid) {
  console.log('Policy binding:', result.policy_binding);
  // 'verified' -- receipt policy matches local policy
  // 'unavailable' -- either receipt or local policy digest absent
}

Policy binding returns one of three states:

State	Meaning
verified	Receipt policy digest matches local policy digest
failed	Digests present but do not match (verification fails)
unavailable	Either receipt or local policy digest is absent

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Result types

Success result

VerifySuccess

interface VerifySuccess {
  valid: true;
  wireVersion: '0.1' | '0.2';
  claims: Wire01Claims | Wire02Claims;
  policy_binding: 'verified' | 'failed' | 'unavailable';
  warnings: VerificationWarning[];  // Wire 0.2 only
}

Failure result

VerifyFailure

interface VerifyFailure {
  valid: false;
  reason: string;
  code: string;  // E_INVALID_SIGNATURE, E_ISS_NOT_CANONICAL, etc.
}

VerificationWarning (Wire 0.2)

Wire 0.2 introduces advisory warnings that do not fail verification:

VerificationWarning

interface VerificationWarning {
  code: string;     // Warning code (e.g., 'type_unregistered')
  message: string;  // Human-readable description
  pointer?: string; // RFC 6901 JSON pointer (e.g., '/type')
}

Warning code	Meaning
type_unregistered	Receipt type is not in the recommended type registry
unknown_extension_preserved	Unknown extension key preserved without schema validation
typ_missing	typ header absent (interop mode only)
occurred_at_skew	occurred_at differs significantly from iat

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CLI verification

Verify a receipt directly from the command line.

Terminal: verify with local keys

npx peac verify <receipt-jws> --jwks keys.json

Terminal: verify with issuer URL

npx peac verify <receipt-jws> --issuer https://api.example.com

The CLI outputs a structured result with pass/fail status for each check.

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MCP server verification

AI agents using the PEAC MCP server can verify receipts via the peac_verify tool.

MCP Tool Call: peac_verify

{
  "tool": "peac_verify",
  "arguments": {
    "receipt": "<jws-string>",
    "issuer_url": "https://api.example.com"
  }
}

The response includes the full verification result, decoded claims, wire version, and server metadata in the _meta field.

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Next steps

Evidence Bundles

Package verified receipts into portable archives for audits and disputes.

Error Codes

Complete reference for verification errors and failure diagnostics.

Conformance Levels

Test your implementation against the official conformance vector suite.