diff --git a/flake.lock b/flake.lock
index b172642..00787d1 100644
--- a/flake.lock
+++ b/flake.lock
@@ -17,7 +17,26 @@
     },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "zentralwerk-network-key": "zentralwerk-network-key"
+      }
+    },
+    "zentralwerk-network-key": {
+      "locked": {
+        "dir": "nix/key",
+        "lastModified": 1616192731,
+        "narHash": "sha256-3FnplUkUgxo3oIQGNd3txRiiuBMHK/lVClfe3N4DYPU=",
+        "ref": "nix",
+        "rev": "5980e925687957f13bf432aff05c6d6d5e75f2cf",
+        "revCount": 863,
+        "type": "git",
+        "url": "https://gitea.c3d2.de/zentralwerk/network.git?dir=nix%2fkey"
+      },
+      "original": {
+        "dir": "nix/key",
+        "ref": "nix",
+        "type": "git",
+        "url": "https://gitea.c3d2.de/zentralwerk/network.git?dir=nix%2fkey"
       }
     }
   },
diff --git a/nix/lib/config/default.nix b/nix/lib/config/default.nix
index 94f661b..c08cd7b 100644
--- a/nix/lib/config/default.nix
+++ b/nix/lib/config/default.nix
@@ -13,7 +13,7 @@ let
         with lib;
         {
           options.gpgKey = mkOption {
-            type = types.path;
+            type = with types; nullOr path;
           };
           config = {
             inherit gpgKey;