diff --git a/app.py b/app.py
index 9ff10f2..19300f0 100644
--- a/app.py
+++ b/app.py
@@ -262,10 +262,9 @@ function setPassword() {
 }
 
 function genPassword() {
-  const chars = "ABCDEFGHJKLMNPQRSTUVWXYZabcdefghjkmnpqrstuvwxyz23456789";
-  const arr = new Uint32Array(10);
+  const arr = new Uint32Array(1);
   crypto.getRandomValues(arr);
-  const pw = Array.from(arr, n => chars[n % chars.length]).join("");
+  const pw = String(arr[0] % 10000).padStart(4, "0");
   $("#pw-input").value = pw;
   $("#pw-input").type = "text";
   $("#pw-msg").textContent = "Copy this password before setting it.";