diff --git a/machine/stel-xps/default.nix b/machine/stel-xps/default.nix
index d55a2f2..80e4043 100644
--- a/machine/stel-xps/default.nix
+++ b/machine/stel-xps/default.nix
@@ -5,6 +5,8 @@
   variables = {
     hostName = "stel-xps";
     graphical = true;
+    git.key = "0x4998BEEE";
+    git.gpgsm = true;
   };
   #networking.hostName = "stel-xps"; # define the hostname
 
diff --git a/options.nix b/options.nix
index a93c16b..1a70a16 100644
--- a/options.nix
+++ b/options.nix
@@ -17,5 +17,18 @@
       default = false;
       description = "Whether this system is a server";
     };
+    git = {
+      key = mkOption {
+        type = types.str;
+        example = "0xBEEE1234";
+        default = "C804A9C1B7AF8256";
+        description = "Signkey for git commits";
+      };
+      gpgsm = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Whether to use gpgsm for commit signatures";
+      };
+    };
   };
 }
diff --git a/users/ellmau/git.nix b/users/ellmau/git.nix
index b1b9bdd..51b2f79 100644
--- a/users/ellmau/git.nix
+++ b/users/ellmau/git.nix
@@ -1,4 +1,4 @@
-{ config, pkgs, ...}:
+{ config, pkgs, lib, ...}:
 {
   home-manager.users.ellmau = {
     programs= {
@@ -9,11 +9,15 @@
         userEmail = "stefan.ellmauthaler@tu-dresden.de";
         extraConfig = {
           core = { editor = "emacsclient"; };
+          gpg = lib.mkIf config.variables.git.gpgsm {
+            format = "x509";
+            program = "gpgsm";
+          };
           #gpg = {
           #  format = "x509";
           #  program = "gpgsm";
           #};
-          user = { signingKey = "C804A9C1B7AF8256"; };
+          user = { signingKey = config.variables.git.key;  };
           init = { defaultBranch = "main";};
           branch = { autosetuprebase = "always";};
         };