Bravo List - userid in with passkey announce.php

How do i tie the passkey to the user id in this piece of code without the userid anyone can get hold of a passkey and use it

so basically when a user downloads it checks the userid and passkey are the same for that user so for example

userid=5 passkey=12345 << system checks both id and passkey can download

userid=6 passkey=12345 << system checks both id and passkey blocks download because passkey is different to that user in database

Code:

$rz = mysql_query("SELECT id, uploaded, downloaded, class, downloadpos, enabled, parked FROM users WHERE enabled = 'yes'". (ENA_PASSKEY ? "AND passkey=$passkey ":''). "ORDER BY last_access DESC LIMIT 1");



if ($MEMBERSONLY && mysql_num_rows($rz) == 0)



err("Unknown passkey. Please redownload the torrent from $BASEURL.");

Thanks