key8[ 6 ] = (byte) ( ( key[ 5 ] << 2 ) | ( ( key[ 6 ] & 0xFF ) >>> 6 ) );
        key8[ 7 ] = (byte) ( key[ 6 ] << 1 );
        for ( int i = 0; i < key8.length; i++ ) {
            key8[ i ] ^= Integer.bitCount(key8[ i ] ^ 1) & 1;
        }
        return key8;
    }

    /**
     * Default provider is BouncyCastleProvider.
     * For registering custom provider