diff --git a/docs/exceptions.rst b/docs/exceptions.rst
index 8ca9df2..38bd0e4 100644
--- a/docs/exceptions.rst
+++ b/docs/exceptions.rst
@@ -42,3 +42,9 @@
 
     This is raised when the verify method of a one time password function's
     computed token does not match the expected token.
+
+
+.. class:: UnsupportedAsymmetricPadding
+
+    This is raised when the chosen asymmetric padding is not supported by the
+    backend.