diff --git a/machines/nix-book/configuration.nix b/machines/nix-book/configuration.nix
index b438a7f..a725a04 100644
--- a/machines/nix-book/configuration.nix
+++ b/machines/nix-book/configuration.nix
@@ -17,8 +17,6 @@
       ../../roles/virtualisation/default.nix
     ];
 
-  nix.settings.secret-key-files = /root/cache-priv-key.pem;
-
   # Bootloader.
   boot.loader.systemd-boot.enable = true;
   boot.loader.efi.canTouchEfiVariables = true;