final byte[] response = new byte[24];
        MessageDigest hmac = Crypto.getHMACT64(passwordHash);
        hmac.update(Strings.getUNIBytes(user.toUpperCase()));
        hmac.update(Strings.getUNIBytes(domain.toUpperCase()));
        hmac = Crypto.getHMACT64(hmac.digest());
        hmac.update(challenge);
        hmac.update(clientChallenge);
        hmac.digest(response, 0, 16);

        }

        final int seqNum = this.signSequence.getAndIncrement();
        final byte[] seqBytes = new byte[4];
        SMBUtil.writeInt4(seqNum, seqBytes, 0);

        final MessageDigest mac = Crypto.getHMACT64(sk);
        mac.update(seqBytes); // sequence
        mac.update(data); // data
        final byte[] dgst = mac.digest();
        byte[] trunc = new byte[8];
        System.arraycopy(dgst, 0, trunc, 0, 8);

                    }
                }

                MessageDigest hmac = Crypto.getHMACT64(ntHash);
                hmac.update(Strings.getUNIBytes(this.username.toUpperCase()));
                hmac.update(Strings.getUNIBytes(this.domain.toUpperCase()));
                byte[] ntlmv2Hash = hmac.digest();
                hmac = Crypto.getHMACT64(ntlmv2Hash);
                hmac.update(chlng);

        }
    }

    /**
     * Get an HMACT64 message authentication code instance.
     * @param key the key for the HMACT64 MAC
     * @return HMACT64 MAC instance
     */
    public static MessageDigest getHMACT64(final byte[] key) {
        return new HMACT64(key);
    }

    /**
     * Get an RC4 cipher instance initialized with the specified key.
     * @param key the encryption key

    void testHMACT64() {
        // Given
        byte[] key = "secret".getBytes();
        byte[] data = "Hello World".getBytes();

        // When
        MessageDigest hmac = Crypto.getHMACT64(key);
        byte[] result = hmac.digest(data);

        // Then
        assertNotNull(result);
        assertTrue(result.length > 0, "HMAC-T64 should produce non-empty result");
    }

    @Test

                final MessageDigest md4 = Crypto.getMD4();
                md4.update(passwordHash);
                final byte[] userSessionKey = md4.digest();

                final MessageDigest hmac = Crypto.getHMACT64(userSessionKey);
                hmac.update(sessionNonce);
                final byte[] ntlm2SessionKey = hmac.digest();

                if (getFlag(NTLMSSP_NEGOTIATE_KEY_EXCH)) {