diff --git a/include/polarssl/pkcs5.h b/include/polarssl/pkcs5.h
index d9b6856..fda40b5 100644
--- a/include/polarssl/pkcs5.h
+++ b/include/polarssl/pkcs5.h
@@ -26,11 +26,11 @@
 #ifndef POLARSSL_PKCS5_H
 #define POLARSSL_PKCS5_H
 
-#include <string.h>
-
 #include "asn1.h"
 #include "md.h"
 
+#include <stddef.h>
+
 #if defined(_MSC_VER) && !defined(EFIX64) && !defined(EFI32)
 #include <basetsd.h>
 typedef UINT32 uint32_t;