diff --git a/src/server/shared/Cryptography/BigNumber.cpp b/src/server/shared/Cryptography/BigNumber.cpp
index 146ea778f48..364ee76ec75 100755
--- a/src/server/shared/Cryptography/BigNumber.cpp
+++ b/src/server/shared/Cryptography/BigNumber.cpp
@@ -16,6 +16,8 @@
  * with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <ace/Guard_T.h>
+
 #include "Cryptography/BigNumber.h"
 #include <openssl/bn.h>
 #include <openssl/crypto.h>