diff --git a/library/padlock.c b/library/padlock.c
index 3a59a22de5..bad25da1cd 100644
--- a/library/padlock.c
+++ b/library/padlock.c
@@ -36,6 +36,8 @@
 
 #include "polarssl/padlock.h"
 
+#include <string.h>
+
 #if defined(POLARSSL_HAVE_X86)
 
 /*