#!/usr/bin/perl -w
use strict;
# first command line argument is for file containing base64 content
my $file = $ARGV[0];
# second command line argument is for the key to use when decoding base64 content
my $key = $ARGV[1];

my $decoded = b6( ttt() );

my $fh;
open($fh, '>', 'gumblar_file') || die "cant create file: $!\n";
binmode($fh);
print $fh $decoded;
close($fh);

sub b6
{
    my ($t) = @_;
    
    my $d = "";
    my ($c1, $c2, $c3, $e1, $e2, $e3, $e4);
    my $j = 0;
    
    my $k = $key;
    
    do
    {
        $e1 = index($k, substr($t, $j++, 1));
        $e2 = index($k, substr($t, $j++, 1));
        $e3 = index($k, substr($t, $j++, 1));
        $e4 = index($k, substr($t, $j++, 1));
        
        $c1 = ($e1 << 2) | ($e2 >> 4);
        $c2 = (($e2 & 15) << 4) | ($e3 >> 2);
        $c3 = (($e3 & 3) << 6) | $e4;
        
        $d .= chr($c1);
        $d .= chr($c2) if $e3 != 64;
        $d .= chr($c3) if $e4 != 64;
        
    } while ($j < length($t));
    
    return $d;
}

sub ttt
{
    my ($args) = @_;
    
    my $ff;
    my $data;
    
    open($ff, $file) || die "cant read $file because: $!\n";
    
    while(<$ff>)
    {
        $data .= $_;
    }
    
    close($ff);
    
    return $data;
}