create-real-testnet-tx.js

// Create REAL Zcash testnet transaction with REAL UTXO
const { proposeTransaction, getSighash, appendSignature, finalizeAndExtract } = require('./dist/index.js');
const secp256k1 = require('secp256k1');
const wallet = require('./testnet-wallet.json');

// UPDATE THESE WITH YOUR REAL UTXO FROM check-balance.js
const UTXO = {
  txid: 'PASTE_TXID_HERE', // From check-balance.js output
  vout: 0,                  // From check-balance.js output
  value: 1000000n,          // Amount in zatoshis from check-balance.js
  scriptPubKey: null,       // Will be generated from public key
};

// Destination (can send back to same address or different one)
const DESTINATION = {
  address: 'tmHufP83dE54sJA92DFmPwMRUxvpsWq4rAu', // Can change this
  amount: 990000n, // Send 0.0099 ZEC (leaving 10000 for fee)
};

async function createRealTransaction() {
  console.log('🔧 Creating REAL Zcash Testnet Transaction\n');

  // Validate
  if (UTXO.txid === 'PASTE_TXID_HERE') {
    console.error('❌ ERROR: Update UTXO details first!');
    console.log('\n📝 Steps:');
    console.log('1. Run: node check-balance.js');
    console.log('2. Copy the UTXO details (txid, vout, value)');
    console.log('3. Update UTXO const in this file');
    console.log('4. Run this script again');
    process.exit(1);
  }

  try {
    // Generate scriptPubKey from public key (P2PKH)
    const publicKey = Buffer.from(wallet.publicKey, 'hex');
    const crypto = require('crypto');

    const sha256 = (buf) => crypto.createHash('sha256').update(buf).digest();
    const ripemd160 = (buf) => crypto.createHash('ripemd160').update(buf).digest();

    const pubKeyHash = ripemd160(sha256(publicKey));

    // P2PKH scriptPubKey: OP_DUP OP_HASH160 <pubKeyHash> OP_EQUALVERIFY OP_CHECKSIG
    const scriptPubKey = Buffer.concat([
      Buffer.from([0x76]), // OP_DUP
      Buffer.from([0xa9]), // OP_HASH160
      Buffer.from([0x14]), // Push 20 bytes
      pubKeyHash,
      Buffer.from([0x88]), // OP_EQUALVERIFY
      Buffer.from([0xac])  // OP_CHECKSIG
    ]);

    console.log('📋 Transaction Details:');
    console.log('   From:', wallet.address);
    console.log('   UTXO:', UTXO.txid.slice(0, 16) + '...');
    console.log('   Vout:', UTXO.vout);
    console.log('   Input Amount:', UTXO.value.toString(), 'zatoshis');
    console.log('   To:', DESTINATION.address);
    console.log('   Send Amount:', DESTINATION.amount.toString(), 'zatoshis');
    console.log('   Fee: ~10000 zatoshis\n');

    // Prepare inputs
    const inputs = [[
      {
        txid: UTXO.txid,
        vout: UTXO.vout,
        sequence: 0xFFFFFFFE, // RBF enabled
      },
      {
        value: UTXO.value,
        scriptPubKey: scriptPubKey,
      }
    ]];

    // Prepare outputs
    const request = {
      payments: [{
        address: DESTINATION.address,
        amount: DESTINATION.amount,
      }]
    };

    // Step 1: Create PCZT
    console.log('1️⃣  Creating PCZT...');
    const pczt = await proposeTransaction(inputs, request);
    console.log('✅ PCZT created');
    console.log('   Inputs:', pczt.transparent?.inputs?.length);
    console.log('   Outputs:', pczt.transparent?.outputs?.length);

    // Step 2: Get sighash
    console.log('\n2️⃣  Computing sighash...');
    const sighash = await getSighash(pczt, 0);
    const sighashHex = Buffer.from(sighash.hash).toString('hex');
    console.log('✅ Sighash:', sighashHex);

    // Step 3: Sign with private key
    console.log('\n3️⃣  Signing with real private key...');
    const privateKey = Buffer.from(wallet.privateKey, 'hex');
    const messageHash = Buffer.from(sighash.hash);

    const sigObj = secp256k1.ecdsaSign(messageHash, privateKey);
    const derSig = secp256k1.signatureExport(sigObj.signature);
    const signature = Buffer.concat([derSig, Buffer.from([0x01])]); // SIGHASH_ALL

    console.log('✅ Signature:', signature.toString('hex').slice(0, 32) + '...');

    // Step 4: Append signature
    console.log('\n4️⃣  Appending signature...');
    const signedPczt = await appendSignature(pczt, 0, signature);
    console.log('✅ Signed');

    // Step 5: Finalize
    console.log('\n5️⃣  Finalizing transaction...');
    const txBytes = await finalizeAndExtract(signedPczt);
    const txHex = Buffer.from(txBytes).toString('hex');

    console.log('✅ Transaction created!');
    console.log('   Size:', txBytes.length, 'bytes');
    console.log('');
    console.log('━'.repeat(60));
    console.log('📤 RAW TRANSACTION HEX:');
    console.log('━'.repeat(60));
    console.log(txHex);
    console.log('━'.repeat(60));

    console.log('\n🚀 Next Steps:');
    console.log('1. Broadcast: node broadcast-tx.js');
    console.log('   (or use zcash-cli -testnet sendrawtransaction)');
    console.log('2. Get TXID from broadcast response');
    console.log('3. Check on explorer: https://blockexplorer.one/zcash/testnet');
    console.log('4. SAVE TXID FOR BOUNTY SUBMISSION!');

    // Save to file
    require('fs').writeFileSync('testnet-tx.hex', txHex);
    console.log('\n💾 Saved to: testnet-tx.hex');

  } catch (error) {
    console.error('\n❌ Error:', error.message);
    console.error(error.stack);
    process.exit(1);
  }
}

createRealTransaction().catch(console.error);