The French semaphore system hack of 200 years ago

Most likely this event inspired Dumas, who put a similar hack in his Count of Monte Cristo novel. It’s funny that Dumas’s hack is less sophisticated that the one done in real life, but the whole chapter is quite well written. It’s available online at [1].

[1] https://en.m.wikisource.org/wiki/The_Count_of_Monte_Cristo/C...

One of the Discworld novels uses 'hacking' of multi-shutter semaphore towers as a plot point, by way of a gibberish sequence that can physically destroy the poorly engineered towers by slamming the shutters around at a resonant frequency (book) or cause the controls to physically seize up in a jammed position (film).

My favorite story that I've talked about as the first "cyber" attack for years is from the time of the second Jewish temple, a few hundred years B.C.

The Jewish calendar is based on the lunar cycle, and each month has either 29 or 30 days. Back then the length of months was not declared in advance. Instead, each month when a new moon was spotted witnesses could come to the religious court (called Sanhedrin) in Jerusalem claiming to have witnessed the new moon, and if the court accepted their testimony that day was declared the first of the month. To spread the word they would light a bonfire on a mountain, and every city that saw the bonfire would light their own and the message would quickly spread. (Similar to the semaphore system but only transmitting a single bit. Because the signal was just a fire at nighttime it would reach very far very quickly)

Now, there was a small offshoot of Jews known as Karaits, whose interpretation of the Bible caused them to believe that passover must fall on a Sunday (the passage says something like "on the first day [of passover] " which can also be interpeted as "on Sunday"). "Mainstream" (at the time) Judaism did not agree with this interpretation. So what did the Karaits do? On the day that they wanted to be the first of the month (such that Passover, the fourteenth of the month, would fall on Sunday) they went to a nearby mountain and lit a bonfire. The other cities saw the bonfire and assumed it was legitimate, and so lit their own bonfires as well, and the fake message was spread. Classic man in the middle attack!

So how did the Sanhedrin solve this issue? One way would be to sign their messages with RSA. Generate two large prime numbers p and q, have N=p*q and e=65537 be public, known parameters, figure out how to properly pad your messages so that you're not using a completely broken system, and sign the hash of the message with phi=(p-1)(q-1).

There are a few problems with this. First, it's difficult to transmit 1024 bit messages over fire signals. Second - Rivest, Shamir and Adelman wouldn't be born for another 2000 years or so.

Instead, the solution was to move to a different, more secure medium. Instead of lighting a fire, the Sanhedrin would send messengers to spread the word to nearby cities, and each city would send their own messengers to their neighbors. Each city would trust their immediate neighbors and a chain of trust could be established.

The problem with the new solution is that it is much much slower than the traditional fire signals, so some far off places wouldn't know when the previous month started by the time the 14th of the month (passover) came around. To handle this, far off cities would celebrate two days of passover - one on the 14th assuming the previous month had 29 days, and one on the following day under the assumption that there were 30 days.

To this day, the tradition of Jews in far off places celebrating 2 days of holidays remains. Orthodox religious Jews outside of Israel celebrate 2 days of each of the 3 major Jewish holidays out of a sense of "doubt" over which day the holiday actually falls on because the message would not arrive in time.

I'm pretty sure you can go back a lot further if you keep redefining the meaning of the word. Would some Roman general sending a spy into an opposing camp to steal codes be a cyber attack?

> Looking back at the incident now, one can see that the French semaphore system was hopelessly insecure,...

Actually, this would have been an ideal application of one-time-pads for end-to-end encryption of the sensitive information, needing no modern tech beyond pencil and paper. The pads could have been passed by hand between participants and would have been highly secure.

Tom Scott did a video on this: https://www.youtube.com/watch?v=cPeVsniB7b0

Very interesting. A less clever but very similar attack, certainly inspired by this, is the described in the great classic "the Count of Monte Cristo", written ten years later. The Count manages to ruin one of his enemies by bribing a semaphore operator in transmitting news of a political unrest in Spain, causing a collapse in the value of foreign bonds (if I remember the details correctly).

An inside job to borrow some network resources does not qualify as an attack on a network.

This is like using your neighbor's Wi-Fi without permission being a "cyber attack".

A better title would be the first hack of a financial market.