diff --git a/src/Open/Security/OpenClientSecretServer.php b/src/Open/Security/OpenClientSecretServer.php
index 9b9dd4b..666bd75 100644
--- a/src/Open/Security/OpenClientSecretServer.php
+++ b/src/Open/Security/OpenClientSecretServer.php
@@ -6,8 +6,8 @@
 include "SecretType.php";
 include "Aes.php";
 include 'MaskHandler.php';
-include "./salsa20/FieldElement.php";
-include "./salsa20/Salsa20.php";
+include "salsa20/FieldElement.php";
+include "salsa20/Salsa20.php";
 
 use Youzan\Open\Security\Salsa20\FieldElement;
 use Youzan\Open\Security\Salsa20\Salsa20;