Crypto Square

practice/crypto-square/crypto_square.py

@@ -1,2 +1,57 @@
+import math
+import re
+
+
 def cipher_text(plain_text):
-    pass
+    """
+    Encodes a plain text message into a cipher text using the square code method.
+
+    The square code method involves arranging the plain text in a rectangle
+    and then reading the text in columns, going from left to right.
+
+    Args:
+        plain_text (str): The plain text message to encode.
+
+    Returns:
+        str: The encoded cipher text.
+
+    Raises:
+        ValueError: If the input is not a string.
+
+    Examples:
+        >>> cipher_text("If man was meant to stay on the ground, god would have given us roots.")
+        'imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn sseoau'
+    """
+    # Remove all non-alphanumeric characters and convert to lower case
+    plain_text = re.sub(r'\W+', '', plain_text).lower()
+
+    # If the plain text is empty, return an empty string
+    if not plain_text:
+        return ""
+
+    # Calculate the number of columns and rows for the rectangle
+    c = math.ceil(math.sqrt(len(plain_text)))
+    r = len(plain_text) // c
+    if len(plain_text) % c != 0:
+        r += 1
+
+    # Split the plain text into rows
+    rows = []
+    for i in range(r):
+        row = plain_text[i*c:(i+1)*c].ljust(c)
+        rows.append(row)
+
+    # Read the text in columns to get the encoded text
+    encoded_text = ""
+    for i in range(c):
+        for row in rows:
+            encoded_text += row[i]
+
+    # Split the encoded text into chunks of length r
+    chunks = []
+    for i in range(c):
+        chunk = encoded_text[i*r:(i+1)*r]
+        chunks.append(chunk)
+
+    # Join the chunks with spaces to get the final cipher text
+    return ' '.join(chunks)