class PreauthHashAndEncryption {
        @Test
        @DisplayName("calculatePreauthHash rejects non-SMB2 or missing negotiation")
        void preauthHash_rejectsWhenUnsupported() {
            // Not SMB2
            assertThrows(SmbUnsupportedOperationException.class, () -> transport.calculatePreauthHash(new byte[] { 1 }, 0, 1, null));

            // SMB2 flag set but no negotiation

        setPrivateField(transport, "smb2", true);
        setPrivateField(transport, "negotiated", negotiateResponse);

        // Calculate hash
        Method calcMethod = findMethod(transport.getClass(), "calculatePreauthHash", byte[].class, int.class, int.class, byte[].class);
        calcMethod.setAccessible(true);

        byte[] input = "test data".getBytes();
        byte[] oldHash = new byte[64];