Admin login security code

[gsruk]

Hi there,

I am Gerard, 1st year student of Perl at the university.
I came across some lines of code from a script done by an ex student that left uni and did not left any explanation of the code.

The only thing I know is that the script reads an external file that contains 2 lines of code.
The 1st and 2nd lines on this file are:


BEGIN!! Addr:* Name:John
-
4DZWJMZMX44ZiaZ4 END!!

I think it compares both lines on the script and return true if equal.

Could some one please explain me better, and how can I create the second line? is it in HExadecimal or what?

Below is the code on the script:

 
$const{'code_validate'} = sub {
    my $p_decode = sub {
        local $_;
        my $code = defined($_[0]) ? $_[0] : '';
        my %map = ();
        my $i = 0;
        foreach (48..57,65..90,97..122) {
            $map{chr($_)} = $i % 16;
            $i++;
        }
        $code =~ s!\s|\r|\n|\015|\012!!sg;
        my $text = '';
        my $frag = '';
        $i = 0;
        while ($frag = substr($code, $i, 2)) {
            $i += 2;
            my $chn = 16 * $map{substr($frag,0,1)};
            $chn += $map{substr($frag,1,1)};
            my $ch = chr($chn);
            $text .= $ch;
        }
        $text = unpack('u',$text);
        return $text;
    };
    local $_;
    my $code = defined($_[0]) ? $_[0] : '';
    return 0 unless ($code);
    my $is_valid = 0;
    $code =~ s!BEGIN!!sg;
    $code =~ s!END!!sg;
    if ($code =~ m!^\s*(.*)\s*\-\s*(.*?)\s*$!s) {
        my ($pub, $pri) = ($1,$2);
        $pri = &$p_decode($pri);
        $pub =~ s!(\s|\r|\n)!!sg;
        $pri =~ s!(\s|\r|\n)!!sg;
        if ($pub eq $pri) {
            $is_valid = 1;
        }
    }
    return $is_valid;
};
 

Thanks for all your help
Gerard

[KevinADC]

same stuff you posted on perlguru where I said that the code you posted seemed to have nothing to do with the question you asked.

There is no need to use that code for anything I can think of.

[gsruk]

Hi Kevin

The script I use reads the text file and compares both lines(like the ones above the code), than if those lines are equal the script assign administrator privileges or secretary priv.

I just would like to know how can I create a script to create the what I think is the hexadecimal code from the second line equal to the written text from the first line.

In that way I can create more privileges to other students according to their Year of studies.

Regards Gerard

[KevinADC]

Sorry, the code is quite confusing. Too bad the author didn't include some comments.