asgayapedia

Payment Covenant Implementation

Purpose: Payment-first covenant with 7% volatility buffer for remittances.

Current Version: v2.6 (5 spending paths)
Status: Production-ready (testnet3 validated Aug 15, 2026)

Files:

• price-oracle-v2.6.cash - CashScript source code (307 lines)
• price-oracle-v2.6.json - Compiled artifact
• version-history.md - Complete evolution from Phase 1 → v2.6

---

Five Spending Paths

1. claim() - Recipient gets BCH (normal path, requires oracle price)
2. merchantCashout() - Merchant cash-out with co-signatures (H€/HAu minting trigger)
3. refund() - Sender recovery (anytime, permissionless)
4. abort() - Emergency exit when price drops ≥6.5% (v2.6 addition)
5. sellerRecoverBuffer() - Seller buffer recovery (post-expiry, sender offline)

---

Oracle Signature Creation (CRITICAL)

⚠️ Important: Oracle signatures MUST use bitcoincashjs-lib crypto library, not Node.js built-in crypto.

Why this matters: CashScript’s checkDataSig expects a specific signature format. Using the wrong crypto library causes checkDataSig rejection, even if the private key and message are correct.

Correct pattern:

import pkg from 'bitcoincashjs-lib';
const { ECPair, networks, crypto } = pkg;

// Load oracle private key
const oracleKey = ECPair.fromWIF(oracleWIF, networks.testnet);

// Create message (16 bytes: timestamp + price, little-endian)
const message = Buffer.allocUnsafe(16);
message.writeBigInt64LE(BigInt(timestamp), 0);
message.writeBigInt64LE(BigInt(priceInCents), 8);

// Sign with bitcoincashjs-lib crypto (NOT Node's crypto)
const messageHash = crypto.sha256(message);
const signatureObj = oracleKey.sign(messageHash);
const signature = signatureObj.toDER();

Wrong pattern (fails checkDataSig):

import crypto from 'crypto';  // ❌ DO NOT USE Node's crypto
const messageHash = crypto.createHash('sha256').update(message).digest();
const signature = oracleKey.sign(messageHash);  // Wrong format

Discovered: August 15, 2026 during testnet3 validation (3 hours of debugging)
Reference: Version History - v2.6

---

How to Compile

# Install CashScript compiler
npm install -g cashc

# Compile
cashc payment-covenant.cash -o payment-covenant.json

---

How to Use

import { Contract, ElectrumNetworkProvider } from 'cashscript';
import artifact from './payment-covenant.json';

// Connect to network
const provider = new ElectrumNetworkProvider('chipnet');

// Create covenant instance
const contract = new Contract(
    artifact,
    [recipientPubkey, senderPubkey, expiryTime],
    provider
);

// Get deterministic address
console.log('Covenant address:', contract.address);

---

Integration

See also:

• Recipient Journey - How recipients use the covenant
• Wallet Implementation - Creating and claiming covenants
• Stability Layer - H€/HAu minting from merchant cash-outs

---

Status: Phase 0 production-ready
Updated: 2026-07-18

This site is open source. Improve this page.