Undetectable quantum computation and communication for alien civilizations
&gt; <i>The distributed computation requires classical communication between receivers, however, similar to standard measurement-based computation, that communication is of purely random outcomes and so can be indistinguishable from noise.</i><p>The main problem of this idea is that you <i>also</i> need a classical channel to transmit the information. You can use natural sources of entangled photons as proposed[1], but you will need a classic channel that can be detected. In the classic channel you will see a random stream of data, so it will be impossible to decode, but you can still see that there is some communication.<p>[1] I think it&#x27;s not so easy, but let&#x27;s ignore this second objection.