From Zero to Blockchain in Python - Part 1 - PoW

validate_proof_of_work.py

@staticmethod
def validate_proof_of_work(last_nonce, last_hash, nonce):
    """
    Validates the nonce

    :param last_nonce: <int> Nonce of the last block
    :param nonce: <int> Current nonce to be validated
    :param last_hash: <str> Hash of the last block
    :return: <bool> True if correct, False if not.
    """
    sha = hashlib.sha256(f'{last_nonce}{last_hash}{nonce}'.encode())
    return sha.hexdigest()[:4] == '0000'

def generate_proof_of_work(self, block):
    """
    Very simple proof of work algorithm:

    - Find a number 'p' such that hash(pp') contains 4 leading zeroes
    - Where p is the previous proof, and p' is the new proof

    :param block: <Block> reference to the last block object
    :return: <int> generated nonce
    """
    last_nonce = block.nonce
    last_hash = block.hash

    nonce = 0
    while not self.validate_proof_of_work(last_nonce, last_hash, nonce):
        nonce += 1

    return nonce