The magician who hacked the wireless in 1903

The story

In June 1903, the physicist John Ambrose Fleming stood in front of an audience at the Royal Institution in London to show off Marconi’s wireless telegraph. A message was due to arrive by radio from Marconi’s station in Cornwall, more than 300 miles away.

Before it came, the receiving equipment in the hall started tapping out a different message in Morse code. It spelled “rats” over and over, followed by rude verses mocking Marconi.

The sender was Nevil Maskelyne, a stage magician and inventor who worked for a rival telegraph company. Marconi had claimed his messages were private and could not be intercepted. Maskelyne wanted to show, publicly, that anyone with the right equipment could listen in and talk over them.

Fleming was furious and called it “scientific hooliganism” in a letter to The Times. Maskelyne replied that he had done it to expose a weakness the public deserved to know about.

Why it mattered

More than a century ago, it showed that a message sent through the air is open to anyone with a receiver. Every wireless technology since, from radio to Wi-Fi, has had to deal with the same problem, which is why wireless connections are now encrypted.

The lesson today

Wireless signals go wherever the air takes them. That was true for Marconi’s telegraph and it is true for office Wi-Fi today. The defense is the same idea Marconi lacked: encrypt what you send, and decide who is allowed to join.