}

    /// Decrypt a block of bytes.
    public void decrypt( byte[] cipherText, byte[] clearText ) {

        decrypt( cipherText, 0, clearText, 0 );
    }

    /**
     * encrypts an array where the length must be a multiple of 8
     */
    public byte[] encrypt(byte[] clearText) {

        int length = clearText.length;

        if (length % 8 != 0) {