diff --git a/modules/common.nix b/modules/common.nix
index 7ed19de..ca47edb 100644
--- a/modules/common.nix
+++ b/modules/common.nix
@@ -2,7 +2,12 @@
 
 {
   time.timeZone = "UTC";
-  services.openssh = { enable = true; };
+  services.openssh = {
+    enable = true;
+    # require public key authentication for better security
+    passwordAuthentication = false;
+    kbdInteractiveAuthentication = false;
+  };
   system.stateVersion = "22.05";
 
   nix = {