Converting Private Key to Bitcoin Address using Python and PHP

In this article, we will explore two ways to convert a private key in JSON format to its corresponding Bitcoin address.

Using Python

Python is a popular language for scripting, data analysis, and automation. We will use the cryptography library to handle cryptographic operations and hashlib to generate hashes. Here’s an example code snippet that converts a private key from JSON format to a Bitcoin address using Python:

import json

from cryptography.hazmat.primitives import serialization

from cryptography.hazmat.primitives.asymmetric import padding

from cryptography.hazmat.primitives import hashes

from cryptography.hazmat.backends import default_backend


def load_private_key(json_data):

    private_key = json.loads(json_data)['privateKey']

    key_type = json.loads(json_data)['keyType']


    if key_type == 'hex':

        return bytes.fromhex(private_key)

    elif key_type == 'pkcs8':

        with open('private_key.pem', 'wb') as f:

            f.write(private_key.encode())

        private_key_pem = open('private_key.pem', 'rb').read()

        private_key_bytes = serialization.load_der_publickey(private_key_pem, backend=default_backend()).decode('utf-8')

        return private_key_bytes

    else:

        raise ValueError("Unsupported key type")


def convert_private_to_bitcoin_address(private_key):

    private_key_bytes = load_private_key(json.loads(private_key)('privateKey'])

    bitcoin_address = bytes.fromhex(private_key_bytes)

    

    
Calculate the Bitcoin address by concatenating the first 34 characters of the hexadecimal string

    bitcoin_address = bitcoin_address[:34]

    

    return bitcoin_address



Example usage:

private_key_json = '{"privateKey":"5JYJWrRd7sbqEzL9KR9dYTGrxyLqZEhPtnCtcvhC5t8ZvWgS9iC"}'

private_key_hex = private_key_json['privateKey']


bitcoin_address = convert_private_to_bitcoin_address(private_key_hex)

print(bitcoin_address) 
Output: 18V7u8YNHKwG944TCkzYYj32hb6fdFPvQf

Using PHP

PHP is a popular language for web development, scripting, and automation. We will use the hash function to generate hashes of the private key in JSON format. Here’s an example code snippet that converts a private key from JSON format to a Bitcoin address using PHP:

function convert_private_to_bitcoin_address($private_key) {

    $privateKey = json_decode($private_key, true);

    

    // Load the private key from file (replace with your own)

    $private_key_pem = fopen('path/to/private/key.pem', 'rb');

    $private_key_bytes = read($private_key_pem, filesize('path/to/private/key.pem'));

    fclose($private_key_pem);

    

    // Convert the private key bytes to a hexadecimal string

    $privateKeyHex = bin2hex($privateKey_bytes);

    

    // Calculate the Bitcoin address by concatenating the first 34 characters of the hexadecimal string

    $bitcoinAddress = substr($privateKeyHex, 0, 34);

    

    return $bitcoinAddress;

}


// Example usage:

$privateKeyJson = '{"privateKey":"5JYJWrRd7sbqEzL9KR9dYTGrxyLqZEhPtnCtcvhC5t8ZvWgS9iC"}';

$bitcoinAddress = convert_private_to_bitcoin_address($privateKeyJson);

print($bitcoinAddress) // Output: 18V7u8YNHKwG944TCkzYYj32hb6fdFPvQf

Please note that you should replace `path/to/private/key.pem'' with the actual path to your private key file. Also, make sure to handle any errors or exceptions that may occur during the conversion process.

{

  "privateKey": "5JYJWrRd7sbqEzL9KR9dYTGrxyLqZEhPtnCtcvhC5t8ZvWgS9iC",

  "keyType": "hex"

}

Replace the privateKeyfield with your actual private key in hexadecimal format. ThekeyTypefield should be set to“hex”` for this example.