hyperreality · August 3, 2016 01:33 · Aug 3, 2016 · Jul 31, 2016
diff --git a/Unicode Substitution Cipher → Unicode Shift Cipher b/Unicode Substitution Cipher → Unicode Shift Cipher
@@ -19,7 +19,7 @@ def unicodeCipher(
     plaintext=(32, 126),
     ciphertext=(19968, 40869),
     ):
-    """Unicode substitution cipher
+    """Unicode shift cipher
 
     Args:
         message (str): The plaintext to be enciphered.

diff --git a/Unicode Substitution Cipher b/Unicode Substitution Cipher
@@ -0,0 +1,68 @@
+#!/usr/bin/python3
+# -*- coding: utf-8 -*-
+
+import random
+
+code_points = {
+    'english': (32, 126),
+    'burmese': (1024, 1279),
+    'arabic': (1536, 1791),
+    'canadian_aboriginal': (5120, 5759),
+    'chinese': (19968, 40869),
+    'korean': (44032, 55216),
+}
+
+
+def unicodeCipher(
+    message,
+    mode,
+    plaintext=(32, 126),
+    ciphertext=(19968, 40869),
+    ):
+    """Unicode substitution cipher
+
+    Args:
+        message (str): The plaintext to be enciphered.
+        mode (str): 'e' for encryption, 'd' for encryption.
+        plaintext (tuple): Tuple of the plaintext unicode start and end points. Defaults to ASCII plaintext. You can use one of the strings defined in the code_points dictionary.
+        ciphertext (tuple): Tuple of the ciphertext unicode start and end points. Defaults to Chinese. You can use one of the strings defined in the code_points dictionary.
+    """
+
+    if mode != 'e' and mode != 'd':
+        raise ValueError('Mode must be e for encryption or d for decryption')
+
+    if type(plaintext) is str:
+        plaintext = code_points[plaintext]
+    if type(ciphertext) is str:
+        ciphertext = code_points[ciphertext]
+
+    plaintext_range = plaintext[1] - plaintext[0] + 1
+    ciphertext_range = ciphertext[1] - ciphertext[0]
+
+    ciphertext_size = ciphertext_range / plaintext_range
+
+    if ciphertext_size < 1:
+        raise ValueError('Ciphertext code point range needs to be larger than plaintext code point range')
+
+    output = []
+
+    if mode == 'e':
+        for letter in message:
+            unicode_decimal = ord(letter) - plaintext[0] + ciphertext[0] + plaintext_range * int(random.uniform(0, ciphertext_size) - 1)
+            output.append(chr(unicode_decimal))
+
+    elif mode == 'd':
+        for letter in message:
+            unicode_decimal = (ord(letter) - ciphertext[0]) % plaintext_range + plaintext[0]
+            output.append(chr(unicode_decimal))
+
+    return ''.join(output)
+
+
+if __name__ == '__main__':
+    example_plaintext = 'This is a Unicode cipher'
+
+    example_ciphertext = unicodeCipher(example_plaintext, 'e', 'english', 'korean')
+    print('Ciphertext: ' + example_ciphertext)
+
+    print('Decrypted: ' + unicodeCipher(example_ciphertext, 'd', 'english', 'korean'))