Pastoid

<?php
// process form
function hmac($data){
	return md5(md5($data) . 'foo boo salt' . md5('this is a very secret key'));
}
$allowed_groups = array('foo', 'bar');
$allowed_groups  = array_combine(array_map('md5', $allowed_groups), $allowed_groups);
 
if (hmac($_POST['group_name']) == $_POST['group_digest']) {
	$group = $allowed_groups[$_POST['group_name']];
}
 
 
// send to form the wanted group info for hidden field
 
$group_name = md5('editors');
$group_digest = hmac($group_name);