Perl CAPTCHA

package KeyCAPTCHA;
use strict;
use warnings;
use Digest::MD5 qw(md5 md5_hex);
use CGI qw/:standard/;
use LWP::Simple;

# Replace PUT_YOUR_PRIVATE_KEY_HERE and PUT_YOUR_USER_ID_HERE
# with proper values from your keycaptcha.com account
my $kc_private_key='PUT_YOUR_PRIVATE_KEY_HERE';
my $kc_user_id = 'PUT_YOUR_USER_ID_HERE';

sub generate_random_string {
    my $res = '';
    $res.= chr int rand(26)+96 for 1..8;
    return $res;
}

sub get_captcha{
    my $self = shift;
    my $p_kc_js_code = "<!-- KeyCAPTCHA code (www.keycaptcha.com) -->
    <script type='text/javascript'>
        var s_s_c_user_id = '$kc_user_id';
        var s_s_c_session_id = '#KC_SESSION_ID#';
        var s_s_c_captcha_field_id = 'capcode';
        var s_s_c_submit_button_id = 'postbut';
        var s_s_c_web_server_sign = '#KC_WSIGN#';
        var s_s_c_web_server_sign2 = '#KC_WSIGN2#';
    </script>
    <script language=JavaScript src='http://backs.keycaptcha.com/swfs/cap.js'></script>
<!-- end of KeyCAPTCHA code -->
";
    my $p_kc_session_id = generate_random_string();
    $p_kc_session_id = md5_hex($p_kc_session_id).'-4.1.0.001';
    my $p_kc_web_server_sign = md5_hex($p_kc_session_id . $ENV{'REMOTE_ADDR'} . $kc_private_key);
    my $p_kc_web_server_sign2 = md5_hex($p_kc_session_id . $kc_private_key);
    
    my $session_id_str = "#KC_SESSION_ID#";
    $session_id_str = quotemeta $session_id_str;
    $p_kc_js_code =~ s/$session_id_str/$p_kc_session_id/g;

    my $web_server_sign2_str = "#KC_WSIGN2#";
    $web_server_sign2_str = quotemeta $web_server_sign2_str;

    $p_kc_js_code =~ s/$web_server_sign2_str/$p_kc_web_server_sign2/g;
    
    
    my $web_server_sign_str = "#KC_WSIGN#";
    $web_server_sign_str = quotemeta $web_server_sign_str;

    $p_kc_js_code =~ s/$web_server_sign_str/$p_kc_web_server_sign/g;

    
    return $p_kc_js_code;
}

sub validate_captcha {
    my ($response) = @_;
    unless ( $response ) {
        return 0;
    }
    my @kc_vars = split(/\|/, $response);
    if ( scalar(@kc_vars) < 4 ) {
        return 0;
    }
    my $kc_s = md5_hex("accept" . $kc_vars[1] . $kc_private_key . $kc_vars[2]);
    if ( $kc_s != $kc_vars[0] ) {
        return 0;
    }
    if ( index($kc_vars[2], "http://") == 0 ) {     
        my $c = get ($kc_vars[2]);
        if ( $c == '1' ) {
            return 1;
        }
    }
    return 0;
}

1;

#!/usr/bin/perl
use CGI qw/:standard/;

sub populatePostFields {
    %postFields = ();
    read( STDIN, $tmpStr, $ENV{ "CONTENT_LENGTH" } );
    @parts = split( /\&/, $tmpStr );
    foreach $part (@parts) {
        ( $name, $value ) = split( /\=/, $part );
        $value =~ ( s/%23/\#/g );
        $value =~ ( s/%2F/\//g );
        $postFields{ "$name" } = $value;
    }
}


print "Content-type: text/html\n\n";
# Replace PATH_TO_KEYCAPTHA with real path to keycaptcha.pm
require ('/PATH_TO_KEYCAPTHA/keycaptcha.pm');


print $ENV{'REMOTE_ADDR'};
print "\n<form method=\"POST\" action=\"\">";
print(KeyCAPTCHA::get_captcha());
print "<input type=hidden id=\"capcode\" name= \"capcode\" value=\"false\">\n";
print "<input name=\"name\">";
print "<input type=submit id=\"postbut\">";
print '</form>';

if(request_method() eq 'POST'){
    &populatePostFields;
    my $capcode = $postFields{'capcode'};
    $capcode =~ s/%([a-f0-9]{2})/pack('C', hex($1))/egi; 

    my $res = KeyCAPTCHA::validate_captcha($capcode);
    if ($res == 1){
        print ("right");
    }else {
        print ("false");
    }
    
}