diff --git a/nix/home-manager/programs/gpg-agent.nix b/nix/home-manager/programs/gpg-agent.nix
index 5fff979..da4ce37 100644
--- a/nix/home-manager/programs/gpg-agent.nix
+++ b/nix/home-manager/programs/gpg-agent.nix
@@ -23,7 +23,9 @@
     enableSshSupport = true;
     grabKeyboardAndMouse = true;
     pinentryFlavor = lib.mkDefault "gtk2";
-    extraConfig = "";
+    extraConfig = ''
+      no-allow-external-cache
+    '';
 
     defaultCacheTtl = 0;
     maxCacheTtl = 0;