fix comment

[fhem-stuff] / HMLAN / HMLAN_CRYPT.pm

package HMLAN_CRYPT;

use Crypt::Rijndael;

sub decrypt(@)
{
	my ($self, $ciphertext) = @_;
	my $plaintext = '';

	while($ciphertext) {
		if($self->{'keystream'}) {
			my $len;

			if (length($self->{'keystream'}) > length($ciphertext)) {
				$len = length($ciphertext);
			} else {
				$len = length($self->{'keystream'});
			}

			my $cpart = substr($ciphertext, 0, $len);
			my $kpart = substr($self->{'keystream'}, 0, $len);

			$ciphertext = substr($ciphertext, $len);
			$self->{'keystream'} = substr($self->{'keystream'}, $len);

			$self->{'ciphertext'} .= $cpart;

			$plaintext .= $cpart ^ $kpart;
		} else {
			$self->{'keystream'} = $self->{'cipher'}->encrypt($self->{'ciphertext'});
			$self->{'ciphertext'}='';
		}
	}

	$plaintext;
}

sub encrypt(@)
{
	my ($self, $plaintext) = @_;
	my $ciphertext = '';

	while($plaintext) {
		if($self->{'keystream'}) {
			my $len;

			if (length($self->{'keystream'}) > length($plaintext)) {
				$len = length($plaintext);
			} else {
				$len = length($self->{'keystream'});
			}

			my $ppart = substr($plaintext, 0, $len);
			my $kpart = substr($self->{'keystream'}, 0, $len);

			$plaintext = substr($plaintext, $len);
			$self->{'keystream'} = substr($self->{'keystream'}, $len);

			$self->{'ciphertext'} .= $ppart ^ $kpart;

			$ciphertext .= $ppart ^ $kpart;
		} else {
			$self->{'keystream'} = $self->{'cipher'}->encrypt($self->{'ciphertext'});
			$self->{'ciphertext'}='';
		}
	}

	$ciphertext;
}

sub new
{
	my $class = shift;
	my $key = shift;
	my $iv = shift;

	my $self = {
		cipher		=> Crypt::Rijndael->new($key, Crypt::Rijndael::MODE_ECB()),
		keystream	=> '',
		ciphertext	=> $iv,
	};

	bless $self, $class;
}

1;