sub modifyKeys(){
  my $self = shift;
  my S_KEY = "";
  my $i, $x;
  For $x = 1 To length($self->{R_KEY})
    $i = ord(substr($self->{R_KEY}, $x, 1)) - 32
    S_KEY = S_KEY + chr(($i ^ $self->{RSORT}[$i] ^ $self->{ATT}) + 32)
  Next x
return S_KEY;
}