Crypt::CFB - Encrypt Data in Cipher Feedback Mode

        use Crypt::CFB;

        my $cipher = new Crypt::CFB $key, 'Crypt::Rijndael';

        my $ciphertext = $cipher->encrypt($plaintext);
        my $plaintext = $cipher->decrypt($ciphertext);

Pure Perl implementation of Cipher Feedback Mode for almost
arbitrary block ciphers and cryptographic hash functions.