diff --git a/library/pk_wrap.c b/library/pk_wrap.c
index b6b8218..f0f09cb 100644
--- a/library/pk_wrap.c
+++ b/library/pk_wrap.c
@@ -27,12 +27,13 @@
 #endif
 
 #if defined(POLARSSL_PK_C)
-
 #include "polarssl/pk_wrap.h"
 
 /* Even if RSA not activated, for the sake of RSA-alt */
 #include "polarssl/rsa.h"
 
+#include <string.h>
+
 #if defined(POLARSSL_ECP_C)
 #include "polarssl/ecp.h"
 #endif