=head1 NAME

IDEA - Perl interface to IDEA block cipher

=head1 SYNOPSIS

    use Crypt::IDEA;
    

=head1 DESCRIPTION

This perl extension is an implementation of the IDEA block cipher algorithm.
The module implements the Crypt::BlockCipher interface,
which has the following methods

=over 4

=item blocksize
=item keysize
=item encrypt
=item decrypt

=back

=head1 FUNCTIONS

=over 4

=item blocksize

Returns the size (in bytes) of the block cipher.

=item keysize

Returns the size (in bytes) of the key.

=item new

	my $cipher = new IDEA $key;

This creates a new IDEA BlockCipher object, using $key,
where $key is a key of C<keysize()> bytes.

=item encrypt

	my $cipher = new IDEA $key;
	my $ciphertext = $cipher->encrypt($plaintext);

This function encrypts $plaintext and returns the $ciphertext
where $plaintext and $ciphertext should be of C<blocksize()> bytes.

=item decrypt

	my $cipher = new IDEA $key;
	my $plaintext = $cipher->decrypt($ciphertext);

This function decrypts $ciphertext and returns the $plaintext
where $plaintext and $ciphertext should be of C<blocksize()> bytes.

=back

=head1 EXAMPLE

	my $key = pack("H32", "0123456789ABCDEF0123456789ABCDEF");
	my $cipher = new IDEA $key;
	my $ciphertext = $cipher->encrypt("plaintex");	# NB - 8 bytes
	print unpack("H16", $ciphertext), "\n";

=head1 SEE ALSO

Crypt::CBD, Crypt::DES, Crypt::Blowfish

Bruce Schneier, I<Applied Cryptography>, 1995, Second Edition,
published by John Wiley & Sons, Inc.


=head1 COPYRIGHT

This implementation is copyright Systemics Ltd ( http://www.systemics.com/ ).

The IDEA algorithm is patented in Europe and the United States
by Ascom-Tech AG.

Module altered between 1999 and 2005  to allow added functionality with perl -MCPAN,
Changes by Dave Paris  (edited lib paths, endian issues, new tests).

Thank you to contributors for endian patches and new test suite!