<?php
require_once("usertable.php");
try {
  $user = $db->real_escape_string($_REQUEST['user']);
  $q = $db->query("select pubkey from user where name='$user';");
  if ($q->num_rows==1) {
    echo json_encode($q->fetch_row()[0]);
  } else {
    echo json_encode(null);
  }
} catch (Exception $e) {
  echo json_encode(null);
}
?>