The CPF is a document here that contains 11 digits

The piece of code below was working fine

===========================================
if (length($cpfmf) != 11) {
$message = $message.$errmsg ;
$found_err = 1 ; }

$errmsg = "

CPF invalid

\n" ;

==========================================

Now non-clients are doing a scam
They just enter 00000000000 and can overcome the code

Is it easy to change this code so that
the scrip could allow only the CPFs on my list
and not only by the lengh anymore ?

Any clue will be wellcome

Moises