feat: initial commit

Author: motorina0

test/integration/silent-payments.spec.ts

@@ -0,0 +1,91 @@
+import BIP32Factory from 'bip32';
+import * as ecc from 'tiny-secp256k1';
+import { describe, it } from 'mocha';
+
+import { regtestUtils } from './_regtest';
+import * as bitcoin from '../..';
+import { toXOnly } from '../../src/psbt/bip371';
+
+const rng = require('randombytes');
+const regtest = regtestUtils.network;
+bitcoin.initEccLib(ecc);
+const bip32 = BIP32Factory(ecc);
+
+describe('bitcoinjs-lib (silent payments)', () => {
+  it('can create (and broadcast via 3PBP) a simple silent payment', async () => {
+    const { senderKeyPair, receiverKeyPair, sharedSecret } = initParticipants();
+    // this is what the sender sees/scans
+    const silentPublicKey = toXOnly(receiverKeyPair.publicKey);
+
+    // the input being spent
+    const { output: p2wpkhOutput } = bitcoin.payments.p2wpkh({
+      pubkey: senderKeyPair.publicKey,
+      network: regtest,
+    });
+
+    // amount from faucet
+    const amount = 42e4;
+    // amount to send
+    const sendAmount = amount - 1e4;
+    // get faucet
+    const unspent = await regtestUtils.faucetComplex(p2wpkhOutput!, amount);
+
+    const psbt = new bitcoin.Psbt({ network: regtest });
+    psbt.addInput({
+      hash: unspent.txId,
+      index: 0,
+      witnessUtxo: { value: amount, script: p2wpkhOutput! },
+    });
+
+    // destination
+    const { address } = bitcoin.payments.p2tr({
+      internalPubkey: silentPublicKey,
+      hash: sharedSecret,
+      network: regtest,
+    });
+    psbt.addOutput({ value: sendAmount, address: address! });
+
+    psbt.signInput(0, senderKeyPair);
+
+    psbt.finalizeAllInputs();
+    const tx = psbt.extractTransaction();
+    const rawTx = tx.toBuffer();
+
+    const hex = rawTx.toString('hex');
+
+    await regtestUtils.broadcast(hex);
+    await regtestUtils.verify({
+      txId: tx.getId(),
+      address: address!,
+      vout: 0,
+      value: sendAmount,
+    });
+  });
+});
+
+function initParticipants() {
+  const receiverKeyPair = bip32.fromSeed(rng(64), regtest);
+  const senderKeyPair = bip32.fromSeed(rng(64), regtest);
+
+
+  const senderSharedSecret = ecc.pointMultiply(
+    receiverKeyPair.publicKey,
+    senderKeyPair.privateKey!,
+  );
+
+  const receiverSharedSecred = ecc.pointMultiply(
+    senderKeyPair.publicKey,
+    receiverKeyPair.privateKey!,
+  );
+
+  if (!toBuffer(receiverSharedSecred!).equals(toBuffer(senderSharedSecret!)))
+    throw new Error('Shared secret missmatch.');
+
+  return {
+    receiverKeyPair,
+    senderKeyPair,
+    sharedSecret: toXOnly(Buffer.from(receiverSharedSecred!)),
+  };
+}
+
+const toBuffer = (a: Uint8Array) => Buffer.from(a);