Code style: Replace tab with space.
diff --git a/include/ndn-cpp/security/identity/memory-private-key-storage.hpp b/include/ndn-cpp/security/identity/memory-private-key-storage.hpp
index 02f8fbc..6184c94 100644
--- a/include/ndn-cpp/security/identity/memory-private-key-storage.hpp
+++ b/include/ndn-cpp/security/identity/memory-private-key-storage.hpp
@@ -6,7 +6,7 @@
  */
 
 #ifndef NDN_MEMORY_PRIVATE_KEY_STORAGE_HPP
-#define	NDN_MEMORY_PRIVATE_KEY_STORAGE_HPP
+#define NDN_MEMORY_PRIVATE_KEY_STORAGE_HPP
 
 #include <map>
 #include "private-key-storage.hpp"