Prerequisites

• Node.js 18+
• npm, yarn, or pnpm

Step 1: Install

npm install @quantzk/attest

This single package includes everything: prover, verifier, registry, transparency log, and verifier registry.

Step 2: Generate Your First Attestation

import { attest } from '@quantzk/attest';

const attestation = await attest({
  pipeline: {
    name: 'Loan Approval',
    manifest: 'fair-lending-v1',
    steps: ['application', 'identity', 'credit', 'fairness', 'pricing', 'decision']
  },
  decision: {
    path: ['application', 'identity', 'credit', 'fairness', 'pricing', 'decision'],
    inputs: { credit_score: 720, income: 85000, debt_ratio: 0.32 },
    outcome: 'decision'
  },
  authority: {
    type: 'legal_review',
    name: 'Covington & Burling LLP',
    ref: 'Opinion #2026-AI-FL-014'
  }
});

console.log(attestation.attestation_id);
// → "vdi:att:0x7a3f..."
console.log(attestation.proof.system);
// → "groth16"

What happened:

1. The attest() function loaded the fair-lending-v1 constraint manifest from the built-in registry
2. It constructed a decision pipeline with 6 steps and 4 constraints
3. It generated a real Groth16 zero-knowledge proof using the circuit artifacts
4. It signed the entire attestation with Ed25519
5. It returned a self-contained, portable attestation object

Your private inputs (credit_score, income, debt_ratio) are never included in the attestation. The ZK proof proves they satisfied all constraints without revealing them.

Step 3: Verify It Offline

import { verify } from '@quantzk/attest';

const result = await verify(attestation);

console.log(result.valid);  // true
console.log(result.steps);
// [
//   { step: 1, name: 'schema', valid: true },
//   { step: 2, name: 'timestamps', valid: true },
//   { step: 3, name: 'pipeline_integrity', valid: true },
//   { step: 4, name: 'policy_integrity', valid: true },
//   { step: 5, name: 'zk_proof', valid: true, detail: 'Groth16 proof mathematically valid' },
//   { step: 6, name: 'signature', valid: true, detail: 'Ed25519 signature valid' },
//   { step: 7, name: 'key_integrity', valid: true, detail: 'Key hash matches' }
// ]

What happened:

1. Schema validation, the attestation has all required fields
2. Timestamp check, not expired, not issued in the future
3. Pipeline integrity, pipeline hash is a valid SHA-256 hex string
4. Policy integrity, constraint manifest hash is valid, authority type is recognized
5. ZK proof verification, Groth16 proof is mathematically valid (the core check)
6. Signature verification, Ed25519 signature over the canonical payload is valid
7. Key integrity, verification key hash matches the embedded key

No server was contacted. No API was called. This runs entirely offline.

Step 4: Emit a Verification Receipt

Verification receipts let you propagate trust without re-verifying the ZK proof.

import { verifyAndReceipt } from '@quantzk/attest';
import { randomBytes } from 'crypto';

const verifierKey = randomBytes(32).toString('hex');

const { verification, receipt } = await verifyAndReceipt(attestation, {
  signingKey: verifierKey,
  verifierId: 'vdi:verifier:my-compliance-bot'
});

console.log(receipt.type);
// → "verification_receipt_v1"
console.log(receipt.result.valid);
// → true
console.log(receipt.signature.algorithm);
// → "Ed25519"

What happened:

1. The full 7-step verification was performed
2. A verification receipt was created with the result
3. The receipt was signed with your Ed25519 key
4. The receipt includes an attestation hash binding it to the original attestation

Step 5: Propagate Trust to a Downstream Agent

Another agent can accept the receipt without re-running the expensive ZK verification.

import { verifyReceipt } from '@quantzk/attest';

const receiptOk = await verifyReceipt(receipt, {
  attestation: attestation,
  trustedVerifiers: ['vdi:verifier:my-compliance-bot']
});

console.log(receiptOk.valid);  // true
console.log(receiptOk.checks);
// [
//   { check: 'expiry', valid: true },
//   { check: 'attestation_binding', valid: true },
//   { check: 'trusted_verifier', valid: true },
//   { check: 'receipt_signature', valid: true }
// ]

What happened:

1. Checked the receipt hasn't expired (24-hour TTL by default)
2. Verified the receipt is bound to the correct attestation (hash match)
3. Confirmed the verifier is in the trusted set
4. Verified the receipt's Ed25519 signature

This takes ~2ms instead of ~27ms for full verification. At scale across 1000 agents, this is the difference between seconds and minutes.

Next Steps

• Core Concepts, Understand the protocol in depth
• API Reference, Full API documentation
• Enterprise Workflows, Real-world examples for lending, healthcare, AI governance
• Trust Model, Deep dive on trust propagation