Update hill_cipher.py

Author: lighting9999

ciphers/hill_cipher.py

@@ -1,8 +1,8 @@
 import string
 
 import numpy as np
-from maths.greatest_common_divisor import greatest_common_divisor
 
+from maths.greatest_common_divisor import greatest_common_divisor
 
 class HillCipher:
     key_string = string.ascii_uppercase + string.digits  # 36 chars
@@ -27,15 +27,15 @@ def check_determinant(self) -> None:
         det = round(np.linalg.det(self.encrypt_key))
         if det < 0:
             det %= len(self.key_string)
-
+        
         error_msg = f"Det {det} not coprime with 36. Try another key."
         if greatest_common_divisor(det, len(self.key_string)) != 1:
             raise ValueError(error_msg)
 
     def process_text(self, text: str) -> str:
         """Uppercase, filter, pad text"""
         chars = [c for c in text.upper() if c in self.key_string]
-        last = chars[-1] if chars else "A"
+        last = chars[-1] if chars else 'A'
         while len(chars) % self.break_key != 0:
             chars.append(last)
         return "".join(chars)
@@ -45,7 +45,7 @@ def encrypt(self, text: str) -> str:
         text = self.process_text(text.upper())
         encrypted = ""
         for i in range(0, len(text), self.break_key):
-            batch = text[i : i + self.break_key]
+            batch = text[i:i+self.break_key]
             vec = [self.replace_letters(c) for c in batch]
             batch_vec = np.array([vec]).T
             product = self.encrypt_key.dot(batch_vec)
@@ -62,13 +62,15 @@ def make_decrypt_key(self) -> np.ndarray:
         det = round(np.linalg.det(self.encrypt_key))
         if det < 0:
             det %= len(self.key_string)
-
+        
         # Find det modular inverse
         det_inv = next(i for i in range(36) if (det * i) % 36 == 1)
-
+        
         # Compute inverse key
         inv_key = (
-            det_inv * np.linalg.det(self.encrypt_key) * np.linalg.inv(self.encrypt_key)
+            det_inv * 
+            np.linalg.det(self.encrypt_key) * 
+            np.linalg.inv(self.encrypt_key)
         )
         return self.to_int(self.modulus(inv_key))
 
@@ -78,7 +80,7 @@ def decrypt(self, text: str) -> str:
         text = self.process_text(text.upper())
         decrypted = ""
         for i in range(0, len(text), self.break_key):
-            batch = text[i : i + self.break_key]
+            batch = text[i:i+self.break_key]
             vec = [self.replace_letters(c) for c in batch]
             batch_vec = np.array([vec]).T
             product = decrypt_key.dot(batch_vec)
@@ -90,26 +92,23 @@ def decrypt(self, text: str) -> str:
             decrypted += decrypted_batch
         return decrypted
 
-
 def main() -> None:
     """Hill Cipher CLI"""
     n = int(input("Enter key order: "))
     print(f"Enter {n} rows of space-separated integers:")
     matrix = [list(map(int, input().split())) for _ in range(n)]
-
+    
     hc = HillCipher(np.array(matrix))
-
+    
     option = input("1. Encrypt\n2. Decrypt\nChoose: ")
     text = input("Enter text: ")
-
+    
     if option == "1":
         print("Encrypted:", hc.encrypt(text))
     elif option == "2":
         print("Decrypted:", hc.decrypt(text))
 
-
 if __name__ == "__main__":
     import doctest
-
     doctest.testmod()
     main()