diff --git a/source/helper/util.py b/source/helper/util.py
index 04365d2..956a953 100644
--- a/source/helper/util.py
+++ b/source/helper/util.py
@@ -59,7 +59,7 @@ class Cert():
         return data
 
     def sign(self, data):
-        args = f'echo -n -e "{data.decode()}" | "{self.OPENSSL}" dgst -sha256 -sign "{self._path_key}" | "{self.OPENSSL}" enc -base64'
+        args = f"echo -n -e '{data.decode()}' | '{self.OPENSSL}' dgst -sha256 -sign '{self._path_key}' | '{self.OPENSSL}' enc -base64"
         data = _call(args).replace('\n', '')
         return data