my @sorted = map  { $_->[0] }
             sort { $a->[1] cmp $b->[1]; } ## magicpipe
             map  { [ $_, expensive($_) } @unsorted;

sub expensive {
   ...
   my $magicpipe = join '|',
      $dir_and_file_name,
      $date_time_mod,
      $file_size,
      $encpd, $deleted_file, $has_iden ;
   return [ $original, lc($magicpipe) ];
}