Email In the 18th Century

morphovar forwards a writeup in Low-tech Magazine recounting an almost-forgotten predecessor to email and packet-switched messaging: the optical telegraph. The article maps out some of the European networks but provides no details of those built in North America in the early 1800s. Man-in-the-middle attacks were dead easy. "More than 200 years ago it was already possible to send messages throughout Europe and America at the speed of an airplane — wireless and without need for electricity. The optical telegraph network consisted of a chain of towers ... placed 5 to 20 kilometers apart from each other. Every tower had a telegrapher, looking through a telescope at the previous tower in the chain. If the semaphore on that tower was put into a certain position, the telegrapher copied that symbol on his own tower. A message could be transmitted from Amsterdam to Venice in one hour's time. A few years before, a messenger on a horse would have needed at least a month's time to do the same."

Comments

The First Time Information Outpaced Man

[Hubec]

Before the semaphore telegraph a man could travel faster than information. Am I the only one who thinks that's just really cool? The whole concept of being able to race across the globe faster than events is completely alien to our current existence.

Hmmm... Let me put it this way; Before the semaphore telegraph, the world was split into a very large number of simultaneous but completely separate realities. As soon as that telegraph came into existence those realities began merging into one.

Man-in-the-middle attacks?

[Dan East]

Man-in-the-middle attacks were dead easy.

No they weren't, and the article doesn't say that they were. Man-in-the-middle attack means that transmitted data can be modified, or entirely new data can be introduced. Think about it. You have a telescope permanently aimed at the next station in line, viewed by a person who has spent thousands of hours staring at that station. Now don't you think if someone, somehow, got in that exact line of sight with their own semaphore in attempt to transmit their own data, that it would be extremely obvious to the operator that something was very wrong?

What the article does say is that the system is vulnerable to eavesdropping. However, a number of solutions would be available. Shutters could be used to restrict visibility of the semaphores to the line of sight of the next tower. Since they were elevated, it would be difficult to get into that line of sight in most terrain. Obviously, the messages themselves could be encrypted as well. The semaphore operators did not have to understand their message. They simply moved the position of their signaling arms to match the position of the sending tower. The sending tower would visually verify that the receiving tower had properly copied the data. The operators did not need to know what the data meant to relay the information - only the initiator and consumer of the information needed the ability to encrypt / decrypt, which is still where we stand today.

Telegraph was very much open to eavesdropping - in fact, I believe it was much easier. Simply pigtail off of any of the thousands of miles of wire, and run a line to a comfortable listening post out of sight of the railway or road. With radio it became even easier!

Dan East

Re:Spam?

[K. S. Kyosuke]

Actually, it wasn't. The electrical telegraph had a very rocky start. Both France and Britain had optical telegraphs in place and were uninterested in investing in this new "electric" form of telegraph. Especially since those who worked on electric telegraphs were often untrained quacks.

In the same way as the transistor had in the first years of its existence? The vacuum tubes' manufacturers certainly also didn't want to give up. Even though the technological progress was already accelerating in the beginning of the 19th century, it was still not quite that fast at the time. (Maybe it had also something to do with slow information dissemination? ;-)) Morse built his first lines sometime around 1845, and the French gave up on Chappe's semaphores in 1850s. For me, this timeframe is "quite soon" - especially when talking about the French. ;-) Maybe a bit of patriotism had also something to do with it. Now, I know about the works of von Sömmering, Schilling, Weber and others, but their constructions don't seem to be practical enough to be really useful - e.g., Schilling's initial eight-wire construction would be barely usable for long distance communication, and the early constructions IIRC didn't solve the problem of recording the transmission, which was clearly an advantage of Morse's invention. Oh, and thanks for the recommendation. I admit that I studied these things some ten years ago, my memory might have degraded a bit since that time.