Title: Writing Raw Bitcoin Transactions with Memo Outputs (OP_RETURN): A Multi-Output Transaction Tool

Introduction

Bitcoin is a decentralized digital currency that allows users to create complex transactions with multiple outputs. One of the main features of Bitcoin is the use of “memo” or “op_return” outputs, which are used to send small amounts of value to specific addresses without revealing the identity of the sender. These memo outputs are commonly used in conjunction with other types of outputs, such as UTXOs (Unspent Transaction Outputs), to create complex transactions. In this article, we will explore a multi-output transaction tool that allows users to write raw Bitcoin transactions with memo outputs.

Why memo outputs?

Memo outputs are useful for several reasons:

• Anonymity: By using memo outputs, you can send small amounts of value to specific addresses without revealing the identity of the sender.

• Flexibility: Memo outputs can be used in conjunction with other output types to create complex transactions.

• Scalability

  : Memo outputs allow for a larger number of transactions per block compared to traditional UTXO outputs.

Building a CLI Tool

To build a multi-output transaction tool using a command-line interface (CLI), we will use the Bitcoin Core API. The following commands and configuration files are required:

• bitcoin-cli is used to create and manage Bitcoin wallets, transactions, and blocks.

• txpool is a separate process that manages the list of unspent transaction outputs (UTXOs) for each wallet.

Here is an example CLI tool in Python:

import bitcoincli
def create_transaction():





Create a new transaction
tx = bitcoincli.Transaction()

Set the memo output parameters
memo_out = {
'address': 'mymemoaddress', 
Memo address
'value': 0.01 
Memo value (1 satoshi)
}

Add memo outputs to the transaction
for key, value in memo_out.items():
tx.add_output(key, bitcoincli.BitcoinValue(value))

Create a new block and add the transaction to it
block = bitcoincli.Block()
block.add_transaction(tx)
return block
def main():
print("Create a new transaction with memo outputs"); memo:")
tx = create_transaction()
print("Transaction details:")
for output in tx.outputs:
print(f"{output.address} - {output.value}")
if __name__ == "__main__":
main()

This script creates a new transaction and adds one or more memo outputs to it. The main function prints the transaction details, which include both regular and memo outputs.

Building a GUI Tool

To build a graphical user interface (GUI) for this CLI tool, we will use a Python library called pyqt5. Here is an example of how you can create a simple GUI:

“`python

import sys

from PyQt5.QtWidgets import QApplication, QWidget, QGridLayout, QLabel, QLineEdit

class TransactionTool(QWidget):

def __init__(self):

super().__init__()

self.memo_out = {}

Create the main layout

gridLayout = QGridLayout()

self.setLayout(gridLayout)

Create labels and input fields for memo address and value

self.memo_address_label = QLabel(“Memo Address:”)

self.memo_value_input = QLineEdit()

Add the labels and input field to the layout grid

gridLayout.addWidget(self.memo_address_label, 0, 0)

gridLayout.addWidget(self.memo_value_input, 0, 1)

Create a button to submit the memo output parameters

submit_button = QPushButton(“Submit”)

submit_button.clicked.connect(self.submit_memo_params)

Add the button to the grid layout

gridLayout.