Encryption has become a top priority for those wanting to protect their privacy online, but US whistleblower Edward Snowden says the security measure could be making it impossible to detect signals sent from...aliens.

Snowden's comments were made during an interview on the 'StarTalk' podcast of astrophysicist and science communicator Neil deGrasse Tyson.

The whistleblower was speaking from Moscow via a robot video link called a “beam remote presence system.” Controlling the robot from Russia, he was able to roll straight into Tyson's office at the Hayden Planetarium in New York.

JUST POSTED: Hero or Traitor? @StarTalkRadio’s exclusive “Conversation w/ Edward Snowden.” On iTunes & http://t.co/nLhC3fBsYa — Neil deGrasse Tyson (@neiltyson) September 19, 2015

When Tyson asked Snowden if a highly intelligent alien civilization might be communicating with encrypted messages, Snowden began by saying that most advanced societies realize they need to encrypt their communications, and that this could be the reason why we've never heard from other civilizations.

“If you have an an alien civilization trying to listen for other civilizations, or our civilization trying to listen for aliens, there’s only one small period in the development of their society when all their communication will be sent via the most primitive and most unprotected means,” Snowden said.

“So when we think about everything that we’re hearing through our satellites or everything that they’re hearing from our civilization (if there are indeed aliens out there), all of their communications are encrypted by default.”

He added that encryption would render communication indistinguishable from “cosmic microwave background radiation.”

“If you look at encrypted communication, if they are properly encrypted, there is no real way to tell that they are encrypted,” Snowden said. “You can’t distinguish a properly encrypted communication from random behavior.”

Snowden is less famous for his views on extraterrestrials and more so for leaking classified documents which revealed the US government's secret mass surveillance program. The whistleblower now resides in Russia, where he was granted asylum after Washington charged him with theft and espionage.