#!/usr/bin/perl
use strict;
use warnings;
use Crypt::CBC;
$|++;

crypto('aes.pl', 'encrypting');
crypto('aes.pl', 'decrypting');

sub crypto {
  my $file = shift;
  my $action = shift;

  my $suffix = $action eq 'encrypting' ? 'aes' : 'no';
  my $cipher = Crypt::CBC->new(-key    => 'pass',
                               -cipher => 'Rijndael');
  my $buffer;
  my $buffer_size = 1024;

  open SOURCEFILE, '<', $file or die $!;  
  open DESTFILE, '>', "$file.$suffix" or die $!;
   my $length = 0;
   $cipher->start($action);
    while ( read(SOURCEFILE, $buffer, $buffer_size) ) {
      $buffer = $cipher->crypt($buffer);
      syswrite(DESTFILE, $buffer, $buffer_size);
    }
    syswrite(DESTFILE, $cipher->finish, $buffer_size);
  close DESTFILE;
  close SOURCEFILE or die $!;

  return 1;
}