Использование HMAC с SHA-256

Block.py

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+import json
+import os
+from dotenv import load_dotenv
+from nonce_finder import NonceFinder
+
+
+class Block:
+    def __init__(
+            self,
+            name,
+            amount,
+            to_whom_name,
+            nonce=0,
+            prev_hash='00000000000000000000000000000000'
+    ):
+        self.name = name
+        self.amount = amount
+        self.to_whom_name = to_whom_name
+        self.nonce = nonce
+        self.prev_hash = prev_hash
+        self.standard_path = 'blockchain_blocks/'
+        dotenv_path = os.path.join(os.path.dirname(__file__), '.env')
+        if os.path.exists(dotenv_path):
+            load_dotenv(dotenv_path)
+        self.key = os.environ.get('KEY')
+
+    def get_last_block(self):
+        """ Получение номера последнего блока """
+        try:
+            files = [int(f.split('.')[0])
+                     for f in os.listdir(self.standard_path) if f.endswith('.txt')]
+            return max(files, default=0)
+        except ValueError:
+            return 0
+
+    def data_creator(self):
+        """ Создание данных блока """
+        return [
+            {'nonce': self.nonce},
+            {'from': self.name, 'amount': self.amount, 'to_whom': self.to_whom_name},
+            {'preview_hash': self.prev_hash}
+        ]
+
+    def get_last_block_hash(self, filename):
+        """ Получение хэша последнего блока """
+        with open(
+                os.path.join(self.standard_path, str(int(filename) - 1) + '.txt'),
+                'r'
+        ) as file:
+            return json.load(file)[1]
+
+    def block_creator(self):
+        """ Создание нового блока """
+        last_file = self.get_last_block()
+        filename = str(last_file + 1)
+        data = self.data_creator()
+        if last_file != 0:
+            data[2]['preview_hash'] = self.get_last_block_hash(filename)
+        block_hash = NonceFinder(data, 4, self.key).create_pow()[1]
+        result_dump_data = [data, block_hash]
+        with open(os.path.join(self.standard_path, filename + '.txt'), 'w') as file:
+            json.dump(result_dump_data, file, indent=4, ensure_ascii=False)
+        if last_file == 0:
+            print('[+] Создан первый блок')
+        else:
+            print(f'[+] Блок {filename} создан')
+
+    def blockchain_checker(self):
+        """ Проверка целостности блокчейна """
+        files = sorted([f for f in os.listdir(self.standard_path) if f.endswith('.txt')],
+                       key=lambda x: int(x.split('.')[0]))
+        for file in files[1:]:
+            with open(os.path.join(self.standard_path, file), 'r') as current_file:
+                current_block = json.load(current_file)
+                prev_hash = current_block[0][2]['preview_hash']
+            prev_file = str(int(file.split('.')[0]) - 1) + ".txt"
+            with open(os.path.join(self.standard_path, prev_file), 'r') as _file:
+                prev_block_data = json.load(_file)[0]
+            real_prev_block_hash = NonceFinder(
+                prev_block_data,
+                4,
+                self.key
+            ).create_pow()[1]
+            if prev_hash == real_prev_block_hash:
+                print(f'[+] Блок {prev_file} верен')
+            else:
+                print(f'[-] В блоке {prev_file} допущена ошибка!')
+        if len(files) <= 1:
+            print('[+] Для начала проверки цепочки блоков, создайте больше блоков!')