@bolyra/receipts

Tamper-evident signed receipts for Bolyra ZKP verification decisions — secp256k1 / ES256K signatures, canonical JSON, EVM-compatible r‖s‖v encoding.

Install

npm install @bolyra/receipts

Usage

import { createAuthReceipt, signReceipt, verifyReceipt } from '@bolyra/receipts';

// 1. Build a receipt from a verification result
const payload = createAuthReceipt(
  {
    rootDid: 'did:bolyra:0xabc…',
    actingDid: 'did:bolyra:0xdef…',
    credentialCommitment: '0x1234…',
    effectiveCommitment: '0x1234…',
    humanProof: verifiedBundle.humanProof,
    agentProof: verifiedBundle.agentProof,
    humanPublicSignals: verifiedBundle.humanPublicSignals,
    agentPublicSignals: verifiedBundle.agentPublicSignals,
    allowed: true,
    score: 95,
    permissionBitmask: 3n,
    chainDepth: 0,
    bundleVersion: 1,
    nonce: '0xdeadbeef',
  },
  { issuer: 'https://gateway.example.com', keyId: 'k1' },
);

// 2. Sign it with your secp256k1 private key
const signed = signReceipt(payload, {
  privateKey: process.env.RECEIPT_SIGNING_KEY!,
  keyId: 'k1',
});

// 3. Verify later (or on another service)
const ok = verifyReceipt(signed, '0xYourExpectedSignerAddress');
console.log(ok); // true

The signed object is JSON-serializable and can be stored in a database, forwarded to an audit log, or returned to the caller as proof of the verification decision.

Hash-chained logs (v0.8.0+)

A signature makes each receipt tamper-evident; it does not make a log of receipts tamper-evident — deleting or reordering whole entries leaves every remaining signature valid. ReceiptChain closes that gap:

import { ReceiptChain, verifyReceiptChain, GENESIS_PREV_RECEIPT_HASH } from '@bolyra/receipts';

// Writer side: one chain per log. Each signed payload gains
// chain: { seq, prevReceiptHash } — the fields are INSIDE the signed payload,
// so they cannot be rewritten without breaking the signature.
const chain = new ReceiptChain();
const first = chain.sign(payload1, signerConfig);  // seq 0, prevReceiptHash = genesis sentinel
const second = chain.sign(payload2, signerConfig); // seq 1, prevReceiptHash = first.receiptHash

// Verifier side: every signature AND the chain links.
const result = verifyReceiptChain([first, second], { expectedSigner: '0x…' });
result.ok;       // true
result.headHash; // pin this externally to detect tail truncation later

Details:

• Genesis sentinel: the first receipt in a log has seq: 0 and prevReceiptHash: GENESIS_PREV_RECEIPT_HASH (0x + 64 zeros).
• receiptHash (envelope field) is computeReceiptHash(receipt): keccak256 over the canonical { payload, signature } — it commits to the exact signature bytes and excludes id and itself. Verifiers recompute it; the stored copy is a convenience for linking and anchoring.
• Backward compatible: all fields are additive. Chain-less receipts keep verifying, chained receipts still pass the plain verifyReceipt(), and chain verification is a separate step. Logs that START with pre-chaining receipts verify with { allowUnchained: true } (deletions among that unchained prefix are, unavoidably, not detectable). Only a prefix is tolerated: a chain-less receipt after any chained receipt always fails (unchained-after-chained) — otherwise a validly signed chain-less receipt could be spliced in undetected.
• What chain verification detects from the log alone: edited receipts, deleted lines, reordered lines, inserted lines, head truncation (missing genesis), and a second chain spliced into the file.
• What it provably cannot detect from the log alone: truncation from the tail — a chain cut after any receipt is still internally consistent. Detecting it requires an external expectation: pass expectedCount and/or expectedHeadHash (e.g. from a periodically anchored checkpoint). The anchoring mechanism and checkpoint cadence are deployment policy — enterprise-configurable, not fixed by this library.

CLI: bolyra receipt verify-chain audit-log.jsonl (from @bolyra/cli) runs the same verification over a JSONL file, with --signer, --expect-count, --expect-head, and --allow-unchained.

License

Apache-2.0