diff --git a/app/common.py b/app/common.py
index b191964..e4c8af1 100644
--- a/app/common.py
+++ b/app/common.py
@@ -45,12 +45,12 @@ def secret_key_check(name: SecretKey) -> None:
     key_file = Path(f'/tmp/{name}')
 
     if key_file.exists():
-        with key_file.open('rt') as f:
+        with key_file.open('rt', encoding='utf-8') as f:
             key = f.read()
 
     else:
         key = secrets.token_hex(32)
-        with key_file.open('wt') as f:
+        with key_file.open('wt', encoding='utf-8') as f:
             f.write(key)
 
     settings_dict[name] = key