diff --git a/configuration/common/default.nix b/configuration/common/default.nix
index e5266b0..c3d09df 100644
--- a/configuration/common/default.nix
+++ b/configuration/common/default.nix
@@ -18,8 +18,10 @@
 
   security.sudo.wheelNeedsPassword = false;
 
+  users.groups.guests = {};
+
   nix.settings = {
-    trusted-users = [ "@wheel" ];
+    trusted-users = [ "@wheel" "@guests" ];
     auto-optimise-store = true;
   };
 
diff --git a/hosts/astatine/configuration.nix b/hosts/astatine/configuration.nix
index 0b4ca09..831426f 100644
--- a/hosts/astatine/configuration.nix
+++ b/hosts/astatine/configuration.nix
@@ -4,6 +4,8 @@
   imports =
     [
       ./hardware-configuration.nix
+
+      ./isa.nix
     ];
 
   boot.kernelParams = [ "console=ttyS0,115200n8" ];
diff --git a/hosts/astatine/isa.nix b/hosts/astatine/isa.nix
new file mode 100644
index 0000000..a42685f
--- /dev/null
+++ b/hosts/astatine/isa.nix
@@ -0,0 +1,11 @@
+{ ... }:
+
+{
+  users.users.isa = {
+    isNormalUser = true;
+    extraGroups = [ "guests" ];
+    openssh.authorizedKeys.keys = [
+      "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIGrvhqC/tZzpLMs/qy+1xNSVi2mfn8LXPIEhh7dcGn9e"
+    ];
+  };
+}