miner.py

from hashlib import sha256


def mine_block(message, target, prev_block=''):
    """
    use the message and previous block to generate a new block
    """
    nonce = 0
    if prev_block:
        message = '%s\n%s' % (message, prev_block)
    maybe = message
    sha = sha256(maybe).hexdigest()
    while not sha.startswith('0' * target):
        maybe = '%s ------ [%s]' % (message, str(nonce))
        sha = sha256(maybe).hexdigest()
        nonce += 1
    return maybe

target = 4
first_block = mine_block("G1: Let's attack at 1337 hours", target=target)
second_block = mine_block("G2: Let's attack at 1337 hours", target=target, prev_block=first_block)
third_block = mine_block("G4: Let's attack at 1337 hours", target=target, prev_block=second_block)

print first_block
print '========='
print second_block
print '========='
print third_block