61 lines
1.9 KiB
Python
61 lines
1.9 KiB
Python
from BlockChain import CBlock
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from Signature import generate_keys, sign, verify
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from cryptography.hazmat.primitives import hashes
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from cryptography.hazmat.backends import default_backend
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import random
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reward = 25.0
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leading_zeros = 2
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next_char_limit = 20
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class TxBlock(CBlock):
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nonce = "A random nonce"
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def __init__(self, previousBlock):
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super(TxBlock, self).__init__([], previousBlock)
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def addTx(self, Tx_in):
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self.data.append(Tx_in)
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def __count_totals(self):
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total_in = 0
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total_out = 0
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for tx in self.data:
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for addr, amt in tx.inputs:
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total_in = total_in + amt
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for addr, amt in tx.outputs:
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total_out = total_out + amt
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return total_in, total_out
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def is_valid(self):
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if not super(TxBlock, self).is_valid():
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return False
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for tx in self.data:
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if not tx.is_valid():
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return False
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total_in, total_out = self.__count_totals()
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if total_out - total_in - reward > 0.000000000001:
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return False
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return True
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def good_nonce(self):
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digest = hashes.Hash(hashes.SHA256(), backend=default_backend())
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digest.update(bytes(str(self.data), 'utf8'))
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digest.update(bytes(str(self.previousHash), 'utf8'))
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digest.update(bytes(str(self.nonce), 'utf8'))
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this_hash = digest.finalize()
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if this_hash[:leading_zeros] != bytes(''.join(['\x4f' for i in range(leading_zeros)]), 'utf8'):
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return False
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return int(this_hash[leading_zeros]) < next_char_limit
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def find_nonce(self):
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for i in range(1000000):
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self.nonce = ''.join([
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chr(random.randint(0, 255)) for i in range(10*leading_zeros)])
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if self.good_nonce():
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return self.nonce
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return None
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