}

    @Test
    @DisplayName("writeSecurityBuffer writes zero length buffer unchanged")
    void testWriteSecurityBufferZeroLength() {
        byte[] dest = new byte[10];
        byte[] before = dest.clone();
        NtlmMessage.writeSecurityBuffer(dest, 0, 4, null);
        assertArrayEquals(before, dest, "Zero length should leave dest unchanged");
    }

            System.arraycopy(NTLMSSP_SIGNATURE, 0, type1, 0, 8);
            writeULong(type1, 8, 1);
            writeULong(type1, 12, flags);
            if (hostInfo) {
                writeSecurityBuffer(type1, 16, 32, domain);
                writeSecurityBuffer(type1, 24, 32 + domain.length, workstation);
            }
            return type1;
        } catch (final IOException ex) {

            pos += 4;

            writeULong(type1, pos, flags);
            pos += 4;

            final int domOffOff = writeSecurityBuffer(type1, pos, domain);
            pos += 8;

            final int wsOffOff = writeSecurityBuffer(type1, pos, workstation);
            pos += 8;

            if ((flags & NTLMSSP_NEGOTIATE_VERSION) != 0) {

    static void writeUShort(final byte[] dest, final int offset, final int ushort) {
        dest[offset] = (byte) (ushort & 0xff);
        dest[offset + 1] = (byte) (ushort >> 8 & 0xff);
    }

    static void writeSecurityBuffer(final byte[] dest, final int offset, final int bodyOffset, final byte[] src) {
        final int length = src != null ? src.length : 0;
        if (length == 0) {
            return;
        }

    static void writeUShort(final byte[] dest, final int offset, final int ushort) {
        dest[offset] = (byte) (ushort & 0xff);
        dest[offset + 1] = (byte) (ushort >> 8 & 0xff);
    }

    static int writeSecurityBuffer(final byte[] dest, final int offset, final byte[] src) {
        final int length = src != null ? src.length : 0;
        if (length == 0) {
            return offset + 4;
        }