* reset.
     *
     * @return the array of bytes for the resulting hash value.
     */
    @Override
    public byte[] engineDigest() {
        // pad output to 56 mod 64; as RFC1320 puts it: congruent to 448 mod 512
        final int bufferNdx = (int) (count % BLOCK_LENGTH);
        final int padLen = bufferNdx < 56 ? 56 - bufferNdx : 120 - bufferNdx;

    }

    /**
     * Perform constant-time encryption to prevent timing attacks
     */
    private byte[] performConstantTimeEncryption(Cipher cipher, byte[] message) throws Exception {
        // Pad to fixed block size to prevent timing leaks
        int blockSize = cipher.getBlockSize();
        if (blockSize == 0)
            blockSize = 16; // GCM mode