diff --git a/engines/e_nuron.c b/engines/e_nuron.c
index 4585dbed1fa77c0b5f627e24e571a829a982fd6b..d7960a9d9526d447cc60ae10ab8503039ad3591d 100644
--- a/engines/e_nuron.c
+++ b/engines/e_nuron.c
@@ -57,6 +57,7 @@
  */
 
 #include <stdio.h>
+#include <string.h>
 #include <openssl/crypto.h>
 #include <openssl/buffer.h>
 #include <openssl/dso.h>