Snowden suggests that encryption can make the Earth invisible in the radio band and then aliens will not find us

Edward Snowden took part in StarTalk podcast of the famous astrophysicist and popularizer of science Neil Degrass Tyson, where he touched his favorite topics - conspiracy and encryption. At the conversation drew the attention of the British The Guardian. Snowden expressed a curious thought: it is possible that an alien civilization finds it necessary to transmit information in encrypted form and in this case it will be very difficult, if not impossible, to separate useful signals from background cosmic radiation.

According to Edward, in the history of human civilization there was a very short period of time when information was transmitted in the radio band in the clear, without the need to conceal it for various reasons. It is possible that the alien community also went through a similar development path and as a result, its message, if it was transmitted at all, would be impossible to isolate from cosmic microwave background radiation. It is likely that if such a message was, or was or will be accepted, then people simply will not understand that these are some kind of meaning-bearing signals. “If you look at properly encrypted communication channels, then there will be no real way to determine if they are encrypted,” said Snowden. For a similar reason, our planet may be virtually invisible to aliens, and then the possibility of communication between civilizations will be lost.

It is impossible not to notice that the interlocutor of Snowden Neil Degrass Tyson reacted to his words with a fair amount of skepticism, translating everything into a joke: “This is if they [aliens] have the same information security problems as we do.”
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The well-known project SETI (Search for Extraterrestrial Intelligence), which has been engaged in the search for extraterrestrial civilizations since 1959, has not yet had any reliable cases of registering any signals of artificial origin. In 1974, a specially encrypted message containing a 23 x 73 dot pattern was sent from the Arecibo radio telescope in the direction of the M13 globular star cluster. True, given the distance to possible recipients, the response signal will have to wait 52,166 years. In the USSR in 1962, a similar attempt was made: a radio-telegraph message from the three words “Peace”, “Lenin”, “USSR” was sent to space.