One more documentation
diff --git a/docs/exceptions.rst b/docs/exceptions.rst
index ab1b28f..b0435b0 100644
--- a/docs/exceptions.rst
+++ b/docs/exceptions.rst
@@ -13,3 +13,7 @@
     This is raised when a backend doesn't support the requested algorithm (or
     combination of algorithms).
 
+
+.. class:: IncorrectPadding
+
+    This is raised when a block cipher's content isn't correctly padded.