diff --git a/src/Site/Controller/User.php b/src/Site/Controller/User.php
index c2a4898..2c7d33c 100644
--- a/src/Site/Controller/User.php
+++ b/src/Site/Controller/User.php
@@ -20,6 +20,7 @@ class User {
 
       $doLogin = $_SERVER['REQUEST_METHOD'] === 'POST';
       $error = '';
+      $nyuU = '';
 
       if ($doLogin) {
         if (!\verify_csrf_token($_POST['csrf_token'])) {
@@ -29,13 +30,21 @@ class User {
         unset($_POST['csrf_token']);
 
         $a = [];
-        if (count($_POST) === 2) {
+        $isBot = false;
+        if (count($_POST) === 4) {
           $i = 0;
           foreach ($_POST as $p) {
             $a[(int)$i] = $p;
+            if ($i >= 2 && $p != '') $isBot = true;
             $i++;
           }
         }
+
+        if ($isBot) {
+          header('Location: /');
+          exit();
+        }
+
         $auth = new Auth($a[0]);
         $res = $auth->isUserExist($a[0]);
         if (!$res->isSuccess) {
@@ -43,6 +52,7 @@ class User {
         } else {
           $result = $auth->setToken($a[0], $a[1]);
           if (!$result->isSuccess) {
+            $nyuU = $a[0];
             $error = $result->message;
           } else {
             header('Location: /');
@@ -60,6 +70,7 @@ class User {
       $tmpl->assign('menu', $this->getMenu());
       $tmpl->assign('description', $description);
       $tmpl->assign('error', $error);
+      $tmpl->assign('nyuU', $nyuU);
 
       $tmpl->render('login');
     } catch (\Exception $e) {
@@ -108,14 +119,21 @@ class User {
         unset($_POST['csrf_token']);
 
         $a = [];
-        if (count($_POST) === 4) {
+        $isBot = false;
+        if (count($_POST) === 8) {
           $i = 0;
           foreach ($_POST as $p) {
             $a[(int)$i] = $p;
+            if ($i >= 4 && $p != '') $isBot = true;
             $i++;
           }
         }
 
+        if ($isBot) {
+          header('Location: /');
+          exit();
+        }
+
         $auth = new Auth;
         $res = $auth->mkUser($a[0], $a[1], $a[2], $a[3]);
         if (!$res->isSuccess) {
diff --git a/util.php b/util.php
index 85d0ae8..50c4409 100644
--- a/util.php
+++ b/util.php
@@ -44,6 +44,46 @@ function kys(mixed $arg): void {
   die();
 }
 
+function ffs(): void {
+  echo '<style>html { color: #fcfcfc; background-color: #232023; } body { margin: 0; }</style>';
+  echo '<header style="padding: 10px 0; display: flex; justify-content: space-evenly; background-color: #b61729; margin-bottom: 20px; position: sticky; top: 0;"><div><b>F</b>OR</div> <div><b>F</b>UCKS</div> <div><b>S</b>AKE</div></header>';
+
+  $stack = debug_backtrace(DEBUG_BACKTRACE_PROVIDE_OBJECT, 50);
+  $st = [];
+  unset($stack[0]);
+  $i = 0;
+
+  echo '<pre>';
+  print_r($stack);
+  echo '<pre>';
+  foreach ($stack as $s) {
+    if (isset($s['file'])) $st[$i]['file'] = $s['file'].(isset($s['line']) ? ':'.$s['line'] : '');
+    else $st[$i]['file'] = '';
+    if (isset($s['function'])) $st[$i]['func'] = (isset($s['class']) ? $s['class'].(isset($s['type']) ? $s['type'] : '::') : '').$s['function'];
+    else $st[$i]['func'] = '';
+    if (isset($s['object'])) $st[$i]['objs'] = $s['object'];
+    else $st[$i]['objs'] = new \stdClass;
+    if (isset($s['args'])) $st[$i]['args'] = $s['args'];
+    else $st[$i]['args'] = [];
+    $i++;
+  }
+  unset($stack[$i]);
+
+  foreach ($st as $s) {
+    echo '<div>';
+    echo '<b>ファイル：</b>';
+    echo $s['file'].'<br />';
+    echo '<b>関数：</b>';
+    echo $s['func'].'<br />';
+    echo '<b>オブジェクト：</b>';
+    echo print_r($s['objs']).'<br />';
+    echo '<b>その他：</b>';
+    echo print_r($s['args']).'<br />';
+    echo '</div>';
+  }
+  die();
+}
+
 function base58btc_encode(string $bin): string {
   $a = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz';
   $base = 58;
@@ -113,8 +153,7 @@ function to_money($amount, $lang) {
 }
 
 function randstr(): string {
-  srand((int)floor(time() / (60*60*24)));
-  $len = rand(1, 20);
+  $len = random_int(1, 20);
   return bin2hex(random_bytes($len));
 }
 
@@ -178,7 +217,7 @@ if (AUTH_ENABLED) {
   }
 
   function verify_csrf_token(string $token): bool {
-    return hash_equals(getcookie('csrf_token'), $token);
+    return null !== getcookie('csrf_token') && hash_equals(getcookie('csrf_token'), $token);
   }
 }
 
diff --git a/view/login.maron b/view/login.maron
index 35860a5..ba3a701 100644
--- a/view/login.maron
+++ b/view/login.maron
@@ -16,19 +16,27 @@
         <form action="/login" method="POST">
           {$ $username = randstr() $}
           {$ $password = randstr() $}
+          {$ $botUsername = randstr() $}
+          {$ $botPassword = randstr() $}
           <table>
             <tbody>
               <tr>
                 <td><label for="{{ $username }}">ユーザー名：</label></td>
-                <td><input type="text" id="{{ $username }}" name="{{ $username }}" /></td>
+                <td><input type="text" id="{{ $username }}" name="{{ $username }}" value="{{ $nyuU }}" /></td>
               </tr>
               <tr>
                 <td><label for="{{ $password }}">パスワード：</label></td>
-                <td><input type="password" id="{{ $password }}" name="{{ $password }}" /></td>
+                <td><input type="password" id="{{ $password }}" name="{{ $password }}" value="" /></td>
               </tr>
               <tr>
                 <td></td>
                 <td>
+                  <div style="position:absolute; left:-9999px;">
+                    <input type="text" id="{{ $username }}" name="{{ $botUsername }} value="" />
+                    <input type="password" id="{{ $password }}" name="{{ $botPassword }}" value="" />
+                  </div>
+
+                  <a href="/?bot=1" style="display:none"></a>
                   <input type="hidden" id="csrf_token" name="csrf_token" value="{{ make_csrf_token() }}" />
                   <button>サインイン</button>
                 </td>
diff --git a/view/register.maron b/view/register.maron
index 7bdb5ca..bca5e79 100644
--- a/view/register.maron
+++ b/view/register.maron
@@ -18,6 +18,10 @@
           {$ $password = randstr() $}
           {$ $passwordVerify = randstr() $}
           {$ $email = randstr() $}
+          {$ $botUsername = randstr() $}
+          {$ $botPassword = randstr() $}
+          {$ $botPasswordVerify = randstr() $}
+          {$ $botEmail = randstr() $}
           <table>
             <tbody>
               <tr>
@@ -39,6 +43,14 @@
               <tr>
                 <td></td>
                 <td>
+                  <div style="position:absolute; left:-9999px;">
+                    <input type="text" id="{{ $botUsername }}" name="{{ $botUsername }} value="" />
+                    <input type="password" id="{{ $botPassword }}" name="{{ $botPassword }}" value="" />
+                    <input type="password" id="{{ $botPasswordVerify }}" name="{{ $botPasswordVerify }}" />
+                    <input type="email" id="{{ $botEmail }}" name="{{ $botEmail }}" value="" />
+                  </div>
+
+                  <a href="/?bot=1" style="display:none"></a>
                   <input type="hidden" id="csrf_token" name="csrf_token" value="{{ make_csrf_token() }}" />
                   <button>登録</button>
                 </td>