cipher: add scytale cipher

Author: Marzhal

ciphers/scytale_cipher.py

@@ -0,0 +1,57 @@
+def encrypt_scytale_cipher(message: str, key: int) -> str:
+    """
+    Encrypts a message using the Scytale Cipher.
+    
+    :param message: Text to encrypt.
+    :param key: Number of rows (key).
+    :return: Encrypted message.
+    """
+    message = message.replace(" ", "")  # Optional: remove spaces
+    ciphertext = [''] * key
+
+    # Distribute characters across rows based on the key
+    for i in range(len(message)):
+        ciphertext[i % key] += message[i]
+
+    return ''.join(ciphertext)
+
+
+def decrypt_scytale_cipher(ciphertext: str, key: int) -> str:
+    """
+    Decrypts a message encrypted with the Scytale Cipher.
+    
+    :param ciphertext: Encrypted text.
+    :param key: Number of rows (key).
+    :return: Decrypted message.
+    """
+    num_cols = -(-len(ciphertext) // key)  # Calculate number of columns (round up)
+    num_rows = key
+    num_shaded_boxes = (num_cols * num_rows) - len(ciphertext)  # Extra unused boxes
+
+    plaintext = [''] * num_cols
+    col = 0
+    row = 0
+
+    # Rebuild the plaintext row by row
+    for char in ciphertext:
+        plaintext[col] += char
+        col += 1
+        # Reset column and move to next row if end of column is reached
+        if (col == num_cols) or (col == num_cols - 1 and row >= num_rows - num_shaded_boxes):
+            col = 0
+            row += 1
+
+    return ''.join(plaintext)
+
+
+# Example usage
+message = "HELLO WORLD FROM SCYTALE"
+key = 5
+
+# Encrypt the message
+ciphered = encrypt_scytale_cipher(message, key)
+print("Encrypted:", ciphered)
+
+# Decrypt the message
+deciphered = decrypt_scytale_cipher(ciphered, key)
+print("Decrypted:", deciphered)