diff --git a/WBAESGenerator.h b/WBAESGenerator.h
index 11b4000..7269d18 100644
--- a/WBAESGenerator.h
+++ b/WBAESGenerator.h
@@ -667,7 +667,8 @@ namespace boost { namespace serialization {
 		}
 		template<class Archive> void save(Archive & ar, const NTL::GF2 & t, unsigned int version)
 		{
-			ar & ((char)rep(t)); // rep returns long, space optimization, store as 1B (GF2 is boolean)
+			char c = rep(t);
+			ar & c; // rep returns long, space optimization, store as 1B (GF2 is boolean)
 		}
 		template<class Archive> void load(Archive & ar, NTL::GF2 & t, unsigned int version)
 		{