diff --git a/system/helpers/string_helper.php b/system/helpers/string_helper.php
index 5177a7e..9fc2455 100644
--- a/system/helpers/string_helper.php
+++ b/system/helpers/string_helper.php
@@ -218,10 +218,10 @@
 						break;
 				}
 				return substr(str_shuffle(str_repeat($pool, ceil($len / strlen($pool)))), 0, $len);
-			case 'unique':
+			case 'unique': // todo: remove in 3.1+
 			case 'md5':
 				return md5(uniqid(mt_rand()));
-			case 'encrypt':
+			case 'encrypt': // todo: remove in 3.1+
 			case 'sha1':
 				return sha1(uniqid(mt_rand(), TRUE));
 		}