diff --git a/RNS/Cryptography/aes/aes.py b/RNS/Cryptography/aes/aes.py
index eabb20b..5244b20 100644
--- a/RNS/Cryptography/aes/aes.py
+++ b/RNS/Cryptography/aes/aes.py
@@ -22,6 +22,7 @@
 
 from .utils import *
 
+# TODO: Add AES-256 support to pure-python implementation
 
 class AES:
     # AES-128 block size