PHP 对用户登录信息 Cookie 进行验证

<?php
unset($username);
if ($_COOKIE['login']) {
list($c_username,$cookie_hash) = split(',',$_COOKIE['login']);
if (md5($c_username.$secret_word) == $cookie_hash) {
$username = $c_username;
} else {
print "You have sent a bad cookie.";
}
}

if ($username) {
print "欢迎, $username.";
} else {
print "欢迎, 游客.";
}
?>