assertArrayEquals(before, dest, "Zero length should leave dest unchanged");
    }

    @Test
    @DisplayName("writeSecurityBuffer copies data and sets fields")
    void testWriteSecurityBufferNonZero() {
        byte[] dest = new byte[8 + 4];
        byte[] payload = { 0x55, 0x66, 0x77 };
        NtlmMessage.writeSecurityBuffer(dest, 0, 8, payload);