Thank you for your replies! In case somebody needs some code to get started, here's mine. Please don't scream when you see my perl...

regards, jan

use Digest::MD5  qw(md5 md5_hex md5_base64);

srand();


$pass = "micz";
$random[0]=int(rand(9));
$random[1]=int(rand(9));
$random[2]=int(rand(9));
$random[3]=int(rand(9));

$num = $random[0].$random[1].$random[2].$random[3];

$concat = $num.$pass;
$hash = md5($concat);

$response[0] = ord(substr($hash, 2, 1));
$response[1] = ord(substr($hash, 7, 1));
$response[2] = ord(substr($hash, 7, 1));
$response[3] = ord(substr($hash, 9, 1));

$totalresponse = 
print "Our challenge is $random[0]-$random[1]-$random[2]-$random[3] (p
+sst, the password is $pass) \n";
print "The correct response is $response[0]-$response[1]-$response[2]-
+$response[3] \n";

exit;
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