#!/usr/bin/perl -w

use Mail::SRS;

$ENV{PATH} = "/var/qmail/bin:/usr/local/bin:/usr/bin:/bin";
$ENV{QMAILSUSER} = "MAILER-DAEMON";
$ENV{QMAILSHOST} = "wooledge.org";

open SECRET, "< $ENV{HOME}/.srs-secret" || die "could not open ~/.srs-secret";
$secret = <SECRET>;
close SECRET;

my $s = new Mail::SRS(Secret => $secret, MaxAge => 10, HashLength => 8);
my $a = $s->reverse($ENV{EXT2} . "\@wooledge.org");
if (defined $a) {
    exec "qmail-inject", "$a";		# valid SRS sender; forward it
} else {
    exec "maildir", "./Maildir/";	# invalid SRS sender; treat as spam
}