#!/usr/bin/perl

use strict;
use warnings;
use Crypt::Rijndael;
use Crypt::CBC;

#--------------------------------------------------------------------
# Parameters
#--------------------------------------------------------------------
my $my_key;
my $plain_text;
my $encrypted = $ARGV[0];
my $cipher;
my $buffer;
my $decrypted = $encrypted;
$decrypted =~ s/\.enc/\.txt/;

$my_key = `openssl enc -bf-cbc -d -in key_file.txt -k encrypt`;
$cipher = Crypt::CBC->new( {'key'             => $my_key,
                            'cipher'          => 'Rijndael',
                            'regenerate_key'  => 1,
                            'padding'         => 'standard',
                           });

#--------------------------------------------------------------------
# Decryption
#--------------------------------------------------------------------

open(FH_encrypted, "<$encrypted");
open(FH_decrypted, ">$decrypted");

$cipher->start('decrypting');
while (read(FH_encrypted,$buffer,1851)) {
   print FH_decrypted $cipher->crypt($buffer); 
}

print FH_decrypted $cipher->finish;
close FH_encrypted;
close FH_decrypted;