4.php (login)

<!DOCTYPE html><html lang="en"><title>Test</title><meta name="viewport" content="width=device-width, initial-scale=1.5"><style>html{font-family:corbel; background:#ec9;}body,p,input,h1,h2,h3{padding:0.3em;margin-left:1em;color:#930;background:#dfe;}</style>
<?php
//DATA ENTERED
$k = file_get_contents($_REQUEST['cn'].".tmp");
if($k==""&$_POST['ws']!=""){$set = fopen($_REQUEST['cn'].".tmp", "x");
$txt = time()."
".$_SERVER['HTTP_USER_AGENT']."
".crc32($_REQUEST['ws'])."
".$_REQUEST['sx'];
fwrite($set,$txt); fclose($set);echo"<h3>Registered! Now login below</h3>";}
echo'<h3>Login here.</h3><a href="3.php" style="background:#000;color:#0ff;">If you don\'t have an account, go here.</a><br><form action="5.php" method="post">
<input name="cn" value="'.$_REQUEST['cn'].'" placeholder="Nick"><br>
<input type="hidden" name="login" value="yep">
<input name="ws" type="password" required placeholder="Code" value="">
<button>Enter</button>
<p>Use the tab keys to speed up form-filling. Then press that magic enter button</p></form>';
?>