}
        int byte2 = bytes[index++];
        if (byte2 > (byte) 0xBF
            // Overlong? 5 most significant bits must not all be zero.
            || (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0)
            // Check for illegal surrogate codepoints.
            || (byte1 == (byte) 0xED && byte2 >= (byte) 0xA0)
            // Third byte trailing-byte test.
            || bytes[index++] > (byte) 0xBF) {
          return false;

        }
        int byte2 = bytes[index++];
        if (byte2 > (byte) 0xBF
            // Overlong? 5 most significant bits must not all be zero.
            || (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0)
            // Check for illegal surrogate codepoints.
            || (byte1 == (byte) 0xED && byte2 >= (byte) 0xA0)
            // Third byte trailing-byte test.
            || bytes[index++] > (byte) 0xBF) {
          return false;

     * The constructor should only use the first 8/32 bytes.
     */
    @Test
    void testAvSingleHostCustomDataMachineIdConstructor_LongerInputs() {
        byte[] customData = { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A }; // Longer than 8
        byte[] machineId = new byte[40]; // Longer than 32
        for (int i = 0; i < 40; i++) {
            machineId[i] = (byte) i;
        }

      Byte[] suffix = {(byte) 86, (byte) 99};
      Byte[] all = concat(concat(prefix, elements), suffix);
      return asList(all).subList(2, elements.length + 2);
    }
  }

  private static Byte[] concat(Byte[] left, Byte[] right) {
    Byte[] result = new Byte[left.length + right.length];
    System.arraycopy(left, 0, result, 0, left.length);
    System.arraycopy(right, 0, result, left.length, right.length);

     * @return the calculated MAC bytes (truncated to 12 bytes)
     * @throws GeneralSecurityException if cryptographic operations fail
     */
    public static byte[] calculateMacHMACAES(int usage, KerberosKey baseKey, byte[] input) throws GeneralSecurityException {
        byte[] cst = { (byte) (usage >> 24 & 0xFF), (byte) (usage >> 16 & 0xFF), (byte) (usage >> 8 & 0xFF), (byte) (usage & 0xFF),
                (byte) 0x99 };

        // fid 0x1234, lastWriteTime 0 -> UTime all 0xFF
        return Stream.of(Arguments.of(0x1234, 0L, new byte[] { 0x34, 0x12, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF }),
                // negative fid wraps around, lastWriteTime = 1000 -> 1 second -> int value 1
                Arguments.of(-1, 1000L, new byte[] { (byte) 0xFF, (byte) 0xFF, 0x01, 0x00, 0x00, 0x00 }));
    }

    /**

    @Test
    @DisplayName("Should set and get lease key")
    void testLeaseKeyAccessors() {
        byte[] newKeyBytes = new byte[] { (byte) 0xFF, (byte) 0xFE, (byte) 0xFD, (byte) 0xFC, (byte) 0xFB, (byte) 0xFA, (byte) 0xF9,
                (byte) 0xF8, (byte) 0xF7, (byte) 0xF6, (byte) 0xF5, (byte) 0xF4, (byte) 0xF3, (byte) 0xF2, (byte) 0xF1, (byte) 0xF0 };
        Smb2LeaseKey newKey = new Smb2LeaseKey(newKeyBytes);

    void testReadULong() {
        byte[] a = new byte[] { (byte) 0x01, (byte) 0x02, (byte) 0x03, (byte) 0x04 };
        int result = NtlmMessage.readULong(a, 0);
        assertEquals(0x04030201, result, "ULong should be little‑endian");
    }

    @Test
    @DisplayName("readUShort correctly interprets little endian")
    void testReadUShort() {
        byte[] a = new byte[] { (byte) 0xAA, (byte) 0xBB };

    @DisplayName("Hex Conversion Tests")
    class HexConversionTests {

        @Test
        @DisplayName("Various byte values are converted to uppercase hex")
        void testHexConversion() {
            byte[] challenge = new byte[] { (byte) 0x00, (byte) 0x0F, (byte) 0x10, (byte) 0x7F, (byte) 0x80, (byte) 0xFF };
            UniAddress dc = mock(UniAddress.class);
            when(dc.toString()).thenReturn("DC");

            (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, // NextCommand
            (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, // MessageId
            (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, // Reserved / AsyncId
            (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, // TreeId / AsyncId