Transaction Signing: We sign the transaction input using the private key.

23.04.2024

Creating a Bitcoin RawTX with Python

Here’s a Python script that creates a Bitcoin RawTX transaction with a positive balance of BTC coins using a private key, along with explanations for each step:

# Import necessary libraries
from bitcoinutils.setup import setup
from bitcoinutils.transactions import Transaction, TxInput, TxOutput
from bitcoinutils.keys import PrivateKey, P2pkhAddress

# Initialize Bitcoin network
setup('testnet')  # Change to 'mainnet' for main network

# Set private key (replace with your actual private key)
private_key = PrivateKey("YOUR_PRIVATE_KEY_HERE")

# Get the corresponding public key and address
public_key = private_key.get_public_key()
address = public_key.get_address()

# Set transaction inputs (replace with your actual UTXO)
# You'll need the txid, output index, and amount
txid = "YOUR_UTXO_TXID"
output_index = 0
amount = 0.001  # Replace with the actual UTXO amount

# Create a TxInput object
tx_input = TxInput(txid, output_index, amount)

# Set transaction outputs
# Replace with the recipient address and amount to send
recipient_address = "RECIPIENT_ADDRESS"
amount_to_send = 0.0005  # Ensure it's less than the input amount

# Calculate the transaction fee
fee = 0.0001  # Adjust as needed

# Create a TxOutput object
tx_output = TxOutput(amount_to_send, recipient_address)

# Create a change output to send remaining balance back to yourself
change_amount = amount - amount_to_send - fee
change_output = TxOutput(change_amount, address)

# Create the transaction
tx = Transaction([tx_input], [tx_output, change_output])

# Sign the transaction
tx.sign_input(0, private_key)

# Get the raw transaction in hex format
raw_tx = tx.serialize()

# Print the raw transaction
print(raw_tx)

Explanation:

  1. Import Libraries: We import necessary libraries from bitcoinutils to work with Bitcoin transactions, keys, and addresses.
  2. Setup Network: We initialize the Bitcoin network using setup. Change testnet to mainnet if you’re working on the main Bitcoin network.
  3. Private Key: Replace "YOUR_PRIVATE_KEY_HERE" with your actual private key in WIF format.
  4. Public Key and Address: We derive the corresponding public key and address from the private key.
  5. Transaction Inputs:
    • Replace "YOUR_UTXO_TXID", output_index, and amount with the details of your unspent transaction output (UTXO).
    • We create a TxInput object representing the input to the transaction.
  6. Transaction Outputs:
    • Replace "RECIPIENT_ADDRESS" with the recipient’s Bitcoin address and set the amount_to_send.
    • We also calculate the change amount to send back to ourselves.
    • We create TxOutput objects for both the recipient and the change.
  7. Transaction Creation: We create a Transaction object with the specified inputs and outputs.
  8. Transaction Signing: We sign the transaction input using the private key.
  9. Raw Transaction: We serialize the transaction to get the raw transaction in hex format.
  10. Output: Finally, we print the raw transaction which can be broadcasted to the Bitcoin network.

Important Notes:

  • Replace placeholders: Make sure to replace all placeholder values with your actual data.
  • UTXO: You need to have a UTXO with enough balance to cover the amount you want to send and the transaction fee.
  • Fees: Adjust the fee variable to reflect the current network fee conditions.
  • Security: Be extremely cautious with your private key. Never share it with anyone and store it securely.

Additional Considerations:

  • This script demonstrates a basic transaction. You can extend it to support more complex scenarios, such as multi-signature transactions or time-locked transactions.
  • Consider using a library like blockcypher or a Bitcoin node’s RPC interface for broadcasting the raw transaction to the network.

Creating a Bitcoin RawTX Transaction with Python

Here’s a Python script that creates a Bitcoin RawTX transaction with a positive balance of BTC coins using a private key. Please note that this is a basic example and you might need to adapt it based on your specific needs and the current state of the Bitcoin network.

Dependencies:

You’ll need to install the following Python libraries:

  • bitcoin
  • base58
pip install bitcoin base58

Script:

from bitcoin import SelectParams
from bitcoin.core import CMutableTransaction, x, b2x, lx, COIN, COutPoint, CMutableTxOut
from bitcoin.core.script import CScript, OP_DUP, OP_HASH160, OP_EQUALVERIFY, OP_CHECKSIG
from bitcoin.wallet import CBitcoinSecret, P2PKHBitcoinAddress

def create_raw_transaction(private_key_wif, recipient_address, amount_btc, fee_btc=0.0001):
    # Select the network (mainnet, testnet, etc.)
    SelectParams('mainnet')

    # Convert WIF to private key
    secret = CBitcoinSecret(private_key_wif)

    # Get the public key and address
    pubkey = secret.pub
    address = P2PKHBitcoinAddress.from_pubkey(pubkey)

    # Get unspent outputs (UTXOs) for the address
    # In a real application, you would need to query a block explorer or use a library like ElectrumX
    utxos = [
        # Replace this with your actual UTXOs
        {
            'txid': 'your_transaction_id',
            'vout': 0,
            'value': 50000000  # Value in Satoshis (5 BTC in this example)
        }
    ]

    # Calculate total input amount and output amount
    total_input = sum([utxo['value'] for utxo in utxos])
    amount_satoshis = int(amount_btc * COIN)
    fee_satoshis = int(fee_btc * COIN)
    total_output = amount_satoshis + fee_satoshis

    # Check if there are enough funds
    if total_input < total_output:
        raise ValueError('Insufficient funds')

    # Create the transaction
    tx = CMutableTransaction()

    # Add inputs
    for utxo in utxos:
        txin = CMutableTxIn(COutPoint(lx(utxo['txid']), utxo['vout']))
        tx.vin.append(txin)

    # Add output
    txout = CMutableTxOut(amount_satoshis, CScript([OP_DUP, OP_HASH160, address, OP_EQUALVERIFY, OP_CHECKSIG]))
    tx.vout.append(txout)

    # Add change output (if necessary)
    if total_input > total_output:
        change_satoshis = total_input - total_output
        change_txout = CMutableTxOut(change_satoshis, CScript([OP_DUP, OP_HASH160, address, OP_EQUALVERIFY, OP_CHECKSIG]))
        tx.vout.append(change_txout)

    # Sign the transaction
    for i, txin in enumerate(tx.vin):
        sig = secret.sign(tx.SignatureHash(i))
        txin.scriptSig = CScript([sig, pubkey])

    # Return the raw transaction in hex format
    return b2x(tx.serialize())

# Example usage
private_key_wif = 'your_private_key_wif'
recipient_address = 'recipient_bitcoin_address'
amount_btc = 0.1

raw_tx = create_raw_transaction(private_key_wif, recipient_address, amount_btc)
print(f"Raw transaction: {raw_tx}")

Explanation:

  1. Dependencies: We import the necessary libraries for working with Bitcoin transactions and addresses.
  2. create_raw_transaction() function: This function takes the private key in WIF format, recipient address, amount to send, and optional fee as input.
  3. Network Selection: We select the Bitcoin network (mainnet in this example) using SelectParams.
  4. Key Conversion: The private key WIF is converted to a CBitcoinSecret object.
  5. Public Key and Address: We derive the public key and address from the private key.
  6. UTXOs: You need to replace the placeholder UTXO information with your actual UTXOs obtained from a block explorer or wallet software.
  7. Amount Calculation: The script calculates the total input amount from UTXOs, the output amount in Satoshis, and the fee.
  8. Funds Check: It ensures there are sufficient funds in the UTXOs to cover the output amount and fee.
  9. Transaction Creation: A CMutableTransaction object is created to build the transaction.
  10. Inputs: The UTXOs are added as inputs to the transaction using CMutableTxIn.
  11. Outputs: An output is created for the recipient address with the specified amount using CMutableTxOut.
  12. Change Output: If there’s remaining balance after sending the desired amount and paying the fee, a change output is created to send the remaining funds back to the sender’s address.
  13. Signing: The transaction is signed using the private key for each input.
  14. Raw Transaction: The serialized and hex-encoded raw transaction is returned.
  15. Example Usage: The script demonstrates how to use the function with sample data. You need to replace the placeholders with your actual private key, recipient address, and amount.

Important Considerations:

  • Security: Never share your private keys publicly. This script is for educational purposes only.
  • UTXOs: You need to obtain your UTXOs from a reliable source like a block explorer or your wallet software.
  • Fees: Adjust the fee based on current network conditions to ensure timely confirmation of your transaction.
  • Error Handling: Implement proper error handling and input validation in a production environment.