@Mock
    private MessageDigest mockMd5;

    @BeforeEach
    void setUp() throws NoSuchAlgorithmException {
        // Mock Crypto.getMD5() to return our mockMd5 instance
        // This requires Mockito 3.4.0+ for MockedStatic
        // For simplicity, we'll assume Crypto.getMD5() is static and mock it.
        // If it's not static, we'd need to inject it or mock the class that provides it.

     *            The initial sequence number for signing
     */
    public SMB1SigningDigest(final byte[] macSigningKey, final boolean bypass, final int initialSequence) {
        this.digest = Crypto.getMD5();
        this.macSigningKey = macSigningKey;
        this.signSequence = initialSequence;
        this.bypass = bypass;

        if (log.isTraceEnabled()) {
            log.trace("macSigningKey:");

        }
    }

    private static byte[] deriveKey(final byte[] masterKey, final String cnst) {
        final MessageDigest md5 = Crypto.getMD5();
        md5.update(masterKey);
        md5.update(cnst.getBytes(StandardCharsets.US_ASCII));
        md5.update((byte) 0);
        return md5.digest();
    }

    @Override

            throws GeneralSecurityException {
        final byte[] sessionHash = new byte[8];

        final MessageDigest md5 = Crypto.getMD5();

        md5.update(serverChallenge);
        md5.update(clientChallenge, 0, 8);
        System.arraycopy(md5.digest(), 0, sessionHash, 0, 8);

        final byte[] key = new byte[21];