Added proof_of_work.py

Author: divyaSree-S0

blockchain/proof_of_work.py

@@ -0,0 +1,31 @@
+import hashlib
+import time
+
+def proof_of_work(difficulty: int) -> int:
+  """
+  Simulates a Proof of Work mining process.
+  
+  The miner must find a nonce such that the hash of the nonce starts 
+  with a specific number of leading zeros (difficulty)
+  
+  Args:
+        difficulty (int): The number of leading zeros required in the hash.
+  Returns:
+        int: The nonce value that solves the puzzle.
+        
+  Example:
+        >>> result = proof_of_work(2)  # Difficulty of 2 should be fast
+        >>> isinstance(result, int)
+        True
+    """
+  prefix = '0' * difficulty
+  nonce = 0
+  start = time.time()  # Timing starts
+
+  while True:
+      hash_result = hashlib.sha256(f"{nonce}".encode()).hexdigest()
+      if hash_result.startswith(prefix):
+          end = time.time()  # Timing ends
+          print(f"Time taken: {end - start:.2f}s")  # Print time taken
+          return nonce
+      nonce += 1