diff --git a/src/CryptKey.php b/src/CryptKey.php
index 2ede9e33..151b57fc 100644
--- a/src/CryptKey.php
+++ b/src/CryptKey.php
@@ -48,7 +48,7 @@ class CryptKey
         if ($keyPermissionsCheck === true) {
             // Verify the permissions of the key
             $keyPathPerms = decoct(fileperms($keyPath) & 0777);
-            if (in_array($keyPathPerms, ['600', '660'], true) === false) {
+            if (in_array($keyPathPerms, ['400', '440', '600', '660'], true) === false) {
                 trigger_error(sprintf(
                     'Key file "%s" permissions are not correct, should be 600 or 660 instead of %s',
                     $keyPath,