diff --git a/src/security/transform.hpp b/src/security/transform.hpp
index 3f83de0..8ecfed5 100644
--- a/src/security/transform.hpp
+++ b/src/security/transform.hpp
@@ -29,6 +29,7 @@
 #include "transform/bool-sink.hpp"
 #include "transform/stream-sink.hpp"
 
+#include "transform/strip-space.hpp"
 #include "transform/hex-encode.hpp"
 #include "transform/hex-decode.hpp"
 #include "transform/base64-encode.hpp"