Creating a transaction in pure Python without Bitcoin locally

In this article, we will explore the possibility of creating a transaction in pure Python using only the Bitcoin core protocol and without Bitcoin locally. We will also explain how you can sign transactions with your private key.

What is a signed transaction?

A signed Bitcoin transaction is basically a message that contains the identity of the sender (the public key) and a digital signature that proves that the sender controls their private keys. The signature is created using a public-private key pair, where the public key is used to identify the sender and the private key is used to sign the transaction.

Can we create a signed transaction in pure Python?

Yes, it is possible to create a signed transaction in pure Python without Bitcoin locally. We will use the “bitcoin” library as an implementation, which provides a Pythonic interface for interacting with the Bitcoin network.

Here is a sample code snippet that shows how to create a signed transaction using a private key:

import bitcoins
def get_public_key(private_key):
"""Get the recipient's public key from the private key."""
return bitcoin.PublicKey.from_private_key(private_key)
def sign_transaction(transaction, private_key):
"""Sign the transaction with the given private key."""
sender = transaction.sender
signature = bitcoin.Signature.sign(
transaction,
bitcoin.PublicKey.get_from_string(sender)
)
return {
'signature': bitcoin.Signature.to_string(signature),
'private_key': private_key.hex()
}

Usage example:
private_key = bitcoin.PrivateKey.from_hex('0123456789012345678901234567890abcdef') 
Replace with your private key
transaction = {
'sender': {
'address': '1A2B3C4D5E6F7G8H9I0J',
'amount': 10.0 
in BTC
},
"signature": "123456789012345678901234567890abcdef"
}
signed_transaction = transaction_signature(transaction, private_key)
result(signed_transaction)

In this example, we create a “Bitcoin” object using the private key as input. We then use the Signature.sign() method to create a signature for the transaction, which includes both the sender’s public key and the transaction data.

The resulting dictionary contains the details of the signed transaction, including the signature and the private key used to sign.

Is this possible?

While we can create a signed transaction in pure Python using the Bitcoin core protocol, there are some limitations to consider:

• The `Bitcoinlibrary is designed to interact with Bitcoin at the protocol level, not to create raw transactions that the Bitcoin network must validate and execute.

• TheSignature.sign()` method creates a single signature that covers all the transaction data. If you want to create multiple signatures for different parts of the transaction, you may need to use a different approach.

In short, while creating a signed transaction in pure Python without using Bitcoin locally is technically possible, it requires some additional setup and considerations to work effectively with the underlying Bitcoin protocol.