Code style: Replace tab with space.
diff --git a/include/ndn-cpp/sha256-with-rsa-signature.hpp b/include/ndn-cpp/sha256-with-rsa-signature.hpp
index 25eb6ae..276c971 100644
--- a/include/ndn-cpp/sha256-with-rsa-signature.hpp
+++ b/include/ndn-cpp/sha256-with-rsa-signature.hpp
@@ -6,7 +6,7 @@
  */
 
 #ifndef NDN_SHA256_WITH_RSA_SIGNATURE_HPP
-#define	NDN_SHA256_WITH_RSA_SIGNATURE_HPP
+#define NDN_SHA256_WITH_RSA_SIGNATURE_HPP
 
 #include "data.hpp"
 #include "key.hpp"