diff --git a/common.nix b/common.nix
index 774f65f..d93b56b 100644
--- a/common.nix
+++ b/common.nix
@@ -29,9 +29,6 @@ with builtins; {
 
   environment = {
     systemPackages = with pkgs; [
-      # pynitrokey
-      # nitrokey-app2
-
       veracrypt
 
       htmlq
@@ -90,10 +87,6 @@ with builtins; {
     };
   };
 
-  # nitrokey
-  services.udev.packages = [pkgs.nitrokey-udev-rules];
-  services.pcscd.enable = true;
-
   programs = {
     ssh.startAgent = false;
     gnupg.agent = {
@@ -138,9 +131,6 @@ with builtins; {
   users.users.jade = {
     isNormalUser = true;
     extraGroups = ["wheel" "input" "uinput" "libvirtd" "adbusers" "dialout" "plugdev" "wireshark"];
-    openssh.authorizedKeys.keys = [
-      "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOaE8TFsIazpn4OnHvHcRpOFr9FfvMaWOiEjmHsmnAoE cardno:000F_70CD7D05"
-    ];
   };
 
   zramSwap = {
diff --git a/hosts/catbook-j/configuration.nix b/hosts/catbook-j/configuration.nix
index 406f484..71d44e0 100644
--- a/hosts/catbook-j/configuration.nix
+++ b/hosts/catbook-j/configuration.nix
@@ -103,55 +103,15 @@
     "/crypto_keyfile.bin" = null;
   };
 
-  # nixpkgs = {
-  #   overlays = [
-  #     (self: super: {
-  #       linux_zen_xeniafied = pkgs.linuxPackagesFor (pkgs.linuxKernel.kernels.linux_zen.override {
-  #         structuredExtraConfig = with lib.kernel; {
-  #           "FB" = yes;
-  #           "FRAMEBUFFER_CONSOLE" = yes;
-  #           "VGA_CONSOLE" = yes;
-  #           "VIDEO_SELECT" = yes;
-  #           LOGO = lib.mkForce yes;
-  #           LOGO_LINUX_CLUT224 = yes;
-  #         };
-  #         ignoreConfigErrors = true;
-  #       });
-  #     })
-  #   ];
-  # };
-
   boot.kernelPackages = pkgs.linuxPackages_zen;
-  # boot.kernelPatches = [
-  #   {
-  #     name = "fomx";
-  #     patch = ../../other/0001-fomx.patch;
-  #   }
-  # ];
-
   services.xserver.displayManager.autoLogin = {
     enable = true;
     user = "jade";
   };
 
-  networking.hostName = "catbook-j"; # Define your hostname.
-  # networking.wireless.enable = true;  # Enables wireless support via wpa_supplicant.
-
-  # Configure network proxy if necessary
-  # networking.proxy.default = "http://user:password@proxy:port/";
-  # networking.proxy.noProxy = "127.0.0.1,localhost,internal.domain";
-
-  # Enable networking
+  # networking
   networking.networkmanager.enable = true;
-
-  security.pam.services.jade.u2fAuth = true;
-  programs.i3lock.u2fSupport = true;
-  security.pam.u2f = {
-    enable = true;
-    cue = true;
-    control = "sufficient";
-    authFile = "/home/jade/.ssh/u2f_keys";
-  };
+  networking.hostName = "catbook-j";
 
   i18n.extraLocaleSettings = {
     LC_ADDRESS = "de_DE.UTF-8";
diff --git a/hosts/monosodium-glutamate-g/configuration.nix b/hosts/monosodium-glutamate-g/configuration.nix
index 7010b36..b6cb3d9 100644
--- a/hosts/monosodium-glutamate-g/configuration.nix
+++ b/hosts/monosodium-glutamate-g/configuration.nix
@@ -8,24 +8,6 @@
     ../../modules
   ];
 
-  # nixpkgs = {
-  #   overlays = [
-  #     (self: super: {
-  #       linux_zen_xeniafied = pkgs.linuxPackagesFor (pkgs.linuxKernel.kernels.linux_zen.override {
-  #         structuredExtraConfig = with lib.kernel; {
-  #           "FB" = yes;
-  #           "FRAMEBUFFER_CONSOLE" = yes;
-  #           "VGA_CONSOLE" = yes;
-  #           "VIDEO_SELECT" = yes;
-  #           LOGO = lib.mkForce yes;
-  #           LOGO_LINUX_CLUT224 = yes;
-  #         };
-  #         ignoreConfigErrors = true;
-  #       });
-  #     })
-  #   ];
-  # };
-
   jade = {
     flatpak.enable = true;
     desktop = {
@@ -46,16 +28,8 @@
       systemd-boot.enable = true;
       efi.canTouchEfiVariables = true;
     };
-    # latest linux kernel
-    #boot.kernelPackages = pkgs.linuxPackages_latest;
-    #boot.kernelPackages = pkgs.linux_zen_xeniafied;
+
     kernelPackages = pkgs.linuxPackages_zen;
-    # boot.kernelPatches = [
-    #   {
-    #     name = "fomx";
-    #     patch = ../other/0001-fomx.patch;
-    #   }
-    # ];
 
     binfmt.emulatedSystems = ["aarch64-linux"];
   };
@@ -82,16 +56,6 @@
     enableRedistributableFirmware = true;
   };
 
-  security.pam.services.jade.u2fAuth = true;
-  programs.i3lock.u2fSupport = true;
-
-  security.pam.u2f = {
-    enable = true;
-    cue = true;
-    control = "sufficient";
-    authFile = "/home/jade/.ssh/u2f_keys";
-  };
-
   # missing: menu-qalc picom-jonaburg
   environment.systemPackages = with pkgs; [
     # TODO: clean up.
diff --git a/hosts/potatobook-g/configuration.nix b/hosts/potatobook-g/configuration.nix
index 28a2e87..c45c889 100644
--- a/hosts/potatobook-g/configuration.nix
+++ b/hosts/potatobook-g/configuration.nix
@@ -116,17 +116,8 @@
   services.gnome.gnome-keyring.enable = true;
   programs.seahorse.enable = true;
   security.pam.services.jade.enableGnomeKeyring = true;
-  security.pam.services.jade.u2fAuth = true;
 
   systemd.services."NetworkManager-wait-online".enable = false;
-  programs.i3lock.u2fSupport = true;
-
-  security.pam.u2f = {
-    enable = true;
-    cue = true;
-    control = "sufficient";
-    authFile = "/home/jade/.ssh/u2f_keys";
-  };
 
   # services.pixiecore =
   #   let
diff --git a/modules/desktop/specific-hardware/default.nix b/modules/desktop/specific-hardware/default.nix
index 8faabd2..a28d10f 100644
--- a/modules/desktop/specific-hardware/default.nix
+++ b/modules/desktop/specific-hardware/default.nix
@@ -7,5 +7,6 @@
   imports = [
     ./spacenav.nix
     ./wacom.nix
+    ./hardware_key.nix
   ];
 }
diff --git a/modules/desktop/specific-hardware/hardware_key.nix b/modules/desktop/specific-hardware/hardware_key.nix
new file mode 100644
index 0000000..8510d86
--- /dev/null
+++ b/modules/desktop/specific-hardware/hardware_key.nix
@@ -0,0 +1,20 @@
+{pkgs, ...}: {
+  # nitrokey
+  services.udev.packages = [pkgs.nitrokey-udev-rules];
+
+  # smartcard daemon
+  services.pcscd.enable = true;
+
+  # authenticate using hw key
+  security.pam = {
+    services.jade.u2fAuth = true;
+    u2f = {
+      enable = true;
+      cue = true;
+      control = "sufficient";
+      authFile = "/home/jade/.ssh/u2f_keys";
+    };
+  };
+
+  programs.i3lock.u2fSupport = true;
+}