{
  nix = {
    settings = {
      substituters = [
        "https://nixcache.vlt81.de"
      ];
      trusted-public-keys = [
        "nixcache.vlt81.de:7yRQAvj1jc1DAmV4ZVKob3CnI5z2PV4XNP6qEc9kbhg=" # new
        "nixcache.vlt81.de:nw0FfUpePtL6P3IMNT9X6oln0Wg9REZINtkkI9SisqQ=" # old
      ];
    };
  };
}