diff --git a/library/pkparse.c b/library/pkparse.c
index bc4fc6e..9a55d6d 100644
--- a/library/pkparse.c
+++ b/library/pkparse.c
@@ -32,6 +32,8 @@
 #include "polarssl/asn1.h"
 #include "polarssl/oid.h"
 
+#include <string.h>
+
 #if defined(POLARSSL_RSA_C)
 #include "polarssl/rsa.h"
 #endif