TechnologyWednesday 04.27.22

How Spies Communicate Using Shortwave Numbers Stations

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What are numbers stations?

Numbers stations are mysterious, unsettling, and one of the strangest things you'll ever hear. They're shortwave radio stations that send coded messages to undercover spies all over the world—an odd relic of Cold War espionage still being used today, including in the Russian invasion of Ukraine.

A typical numbers station broadcast starts with a snippet of a song or melody followed by a monotone voice reading off a list of random numbers, maybe in Russian, English, Czech, or even Morse Code.

The numbers are encrypted messages being sent to undercover spies and intelligence operatives using a century-old encryption method called one-time pads. Anyone with a shortwave radio can hear the messages, and the radio signals have been traced back to government sites in Russia, Cyprus, even the United States, but no government has ever acknowledged their existence.

Numbers stations solve an age-old problem for intelligence agencies: how do you securely communicate with agents in the field without anyone knowing what you’re saying? Experts say that shortwave radio and one-time pad encryption is the only covert communication that’s completely unbreakable.

The Recount dives into the mysterious and fascinating world of numbers stations to learn more about how they work, where they come from, and why they’re still an important part of modern espionage, including in Russia’s invasion of Ukraine.

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