|
| 1 | +import hashlib |
| 2 | +import time |
| 3 | +from datetime import datetime |
| 4 | + |
| 5 | +class Block: |
| 6 | + def __init__(self, index: int, previous_hash: str, data: str, timestamp: str): |
| 7 | + self.index = index |
| 8 | + self.previous_hash = previous_hash |
| 9 | + self.data = data |
| 10 | + self.timestamp = timestamp |
| 11 | + self.nonce = 0 |
| 12 | + self.hash = self.calculate_hash() |
| 13 | + |
| 14 | + def calculate_hash(self) -> str: |
| 15 | + value = (str(self.index) + str(self.previous_hash) + |
| 16 | + str(self.data) + str(self.timestamp) + str(self.nonce)) |
| 17 | + return hashlib.sha256(value.encode('utf-8')).hexdigest() |
| 18 | + |
| 19 | + def mine_block(self, difficulty: int) -> None: |
| 20 | + target = '0' * difficulty |
| 21 | + while self.hash[:difficulty] != target: |
| 22 | + self.nonce += 1 |
| 23 | + self.hash = self.calculate_hash() |
| 24 | + print(f"Block mined: {self.hash}") |
| 25 | + |
| 26 | +class Blockchain: |
| 27 | + def __init__(self): |
| 28 | + self.chain = [self.create_genesis_block()] |
| 29 | + self.difficulty = 4 |
| 30 | + |
| 31 | + def create_genesis_block(self) -> Block: |
| 32 | + return Block(0, "0", "Genesis Block", datetime.now().isoformat()) |
| 33 | + |
| 34 | + def get_latest_block(self) -> Block: |
| 35 | + return self.chain[-1] |
| 36 | + |
| 37 | + def add_block(self, new_block: Block) -> None: |
| 38 | + new_block.previous_hash = self.get_latest_block().hash |
| 39 | + new_block.mine_block(self.difficulty) |
| 40 | + self.chain.append(new_block) |
| 41 | + |
| 42 | +# Example usage |
| 43 | +blockchain = Blockchain() |
| 44 | +blockchain.add_block(Block(1, "", "Block 1 Data", datetime.now().isoformat())) |
| 45 | +blockchain.add_block(Block(2, "", "Block 2 Data", datetime.now().isoformat())) |
| 46 | + |
| 47 | +# Display the blockchain |
| 48 | +for block in blockchain.chain: |
| 49 | + print(f"Block {block.index} - Hash: {block.hash} - Data: {block.data}") |
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