I had no idea these towers exist before I learned that someone hacked (to use the term loosely) them. — Dan

In our digital world, cybersecurity is very important. Sources vary widely, but American companies alone invest billions of dollars a year keeping their networks safe from hackers and scammers. The danger these bad guys can cause is massive — for example, in 2024, a ransomware attack at a hospital resulted in a dead patient. But attacks need not be that extreme in order to be effective. Simply getting access to a company’s or government’s network — and their information — can be profitable for the cybercriminal. If you can gain unauthorized access to someone else’s systems, you can make a fortune.

And that’s nothing new. Before there were computers, bandits roamed another type of information superhighway — towers, like the one seen below.

That’s called an optical telegraph or a semaphore telegraph. The one pictured is in Germany, and it’s not all that old — it’s a replica of the buildings you’d have found in parts of Europe, and particularly in France, as early as the 1790s. They were used as a communications network. Each tower had a mast and a pair of movable arms attached to it — those arms were called the “semaphore.” The operator of the tower could position those arms into certain positions, each one corresponding to a number or letter. Towers like these dotted the landscape, with the operator of each one able to see the next through a telescope. The operator at the beginning of the chain would, using semaphore code, spell out sentences one character at a time, and the next tower operator in the line would mirror what he saw. Using these towers, messages that would otherwise take days to travel from point to point (by mail, typically), could cross large distances in mere hours if not minutes.

The French semaphore system, known as the Chappe Network, got its start in 1796 and was used by Napoleon to monitor troop movements from afar. The French government expanded it over the decades, and by the 1830s, the network crisscrossed the nation. It was reserved for government use, and that didn’t sit well with a pair of bankers, François and Joseph Blanc. As the Economist explains, “the Blanc brothers traded government bonds at the exchange in the city of Bordeaux, where information about market movements took several days to arrive from Paris by mail coach. Accordingly, traders who could get the information more quickly could make money by anticipating these movements.” And the semaphore network seemed like a perfect way to get that information flowing faster.

Their plan was simple and elegant, As NordVPN (yes, even antivirus sites have bloggers these days) explains, the duo “hired someone in Paris to closely monitor the stock exchange. If there were any significant changes, the accomplice would send packages of clothing to Tours, which was about halfway from Paris to Bordeaux. The colors of the clothing signified specific changes in the market.” Then, the Blancs’ bribed the Tours semaphore operator to transmit a quick, one-character message articulating the market change, followed by the backspace character, which informed the next network operator to ignore the previous character. That “erroneous” character wouldn’t make it into the final semaphore message, but it was displayed at Tours for long enough for someone closer to Bordeaux to take notice. That someone — a former operator — was also on the Blancs’ payroll, and he relayed the secret message to the brothers. They would then trade on the information, making a risk-free profit when the news finally arrived by mail. The Blancs had successfully hacked the semaphore network.

Their scheme went on for about two years, starting in 1834 and running through 1836. The flaw in the plan? Their man in Tours fell ill and enlisted a friend in his place, but that friend’s conscience got the better of him and he turned in everyone involved. But the Blancs never received any prison time — it turned out that France had no law against abusing the semaphore network or for engaging in what today could be considered a financial crime. They were the first to prove that wherever there’s a communication network, someone will find a way to exploit it, and got away with it.

Morning Brew makes business news way more enjoyable—and way easier to understand. The free newsletter breaks down the latest in business, tech, and finance with smart insights, bold takes, and a tone that actually makes you want to keep reading.

No jargon, no drawn-out analysis, no snooze-fests. Just the stuff you need to know, delivered with a little personality.

Over 4 million people start their day with Morning Brew, and once you try it, you’ll see why.

Plus, it takes just 15 seconds to subscribe—so why not give it a shot?

Check it out

Today’s Bonus fact: Hackers often get access to systems not by cracking passwords with fancy technology, but by preying on the trust of unsuspecting targets who, ultimately, hand over the key information without a second thought. That’s called “social engineering.” And the same principles can be used by the good guys to catch criminals. In 2008, a Secret Service agent named Matt O’Neill was trying to arrest a Romanian hacker who had broken into the point-of-sale computers used by Subway, the sandwich chain. The Service wanted to arrest the hacker in the United States, to avoid having to extradite him, but the hacker wasn’t planning on leaving Romania (and certainly, wouldn’t have if he thought he was going to be arrested). So the Secret Service agent ran a scam of his own. As CNBC reported, “O’Neill said he contacted the suspected hacker by posing as a female casino employee in an effort to entice him to come to the United States for what he thought would be a gambling outing. [ . . . ] O’Neill said over the next several months he developed a “quasi-romantic” relationship with the suspect, at times chatting online with him at 3 a.m. while he fed his newborn baby as his wife slept in another room at home.” The hacker ultimately came to Boston to visit his online girlfriend, only to discover the ruse. He was convicted and sentenced to seven years in prison.

From the Archives: The Most Unlikely Hacker: She probably didn’t mean to do it.

Now I Know is supported by readers like you. Yes, you! Many of my readers donate a few dollars a month to help Now I Know grow and thrive. And in exchange, they get an ad-free version!

Interested in supporting Now I Know? Click here!

And thanks! — Dan