Privacy and communication are a much debated topic nowadays, and I'm wondering whether it has always been the case, or if we've come to expect privacy in our communication only recently.
The telegraph, I assume, was a fairly technical way of communication, with intermediaries along the chain. Both trivial and sensitive data was communicated through it, but with so many people handling it "in the open", were people expecting the communication to be private, or did they know that at least some strangers would read it? Did they mind?
Did they know that at least some strangers would read it? Did they mind?
Yes and yes. The telegraph companies did make serious efforts to assure their customers that they would respect secrecy, and ultimately most people who weren't involved in genuinely high-stakes, secretive activities reconciled themselves to the small possibility of malicious interception, much as people today are mostly sanguine about the chance that the NSA can read their love letters (despite what you see in /r/worldnews...)
For people who did worry, and worry enough to distrust the obvious course of using euphemisms and oblique language, there were many published telegraphic codes and ciphers. These were universally invented by dilettantes – there were no real cryptographers, yet – and none of them could have offered real security, but most would have been sufficient to deter casual eavesdropping. These became known as commercial codes, because they were actually more useful for businessmen to economize on message length. (This would have provided an extra layer of security-through-obscurity for people with real secrets, in that their messages would look pretty much the same as those of commercial users, if they used one of the codebooks.)
This website implements the ABC Telegraphic Code, which allowed one to send, for example,
INCULCATE TITANIC COACH SULTANSHIP MUDFISH LUMBAGO PARADOXY ISMAY
which meant,
Very grieved to inform you Titanic has been in collision with an iceberg. Sunk at sea this morning with great loss of life. Further particulars will be sent soon as possible by telegraph. Ismay.
And really was Ismay's message.
People who at least trusted the mails could also pre-arrange simple codes. When Count Izvolsky expected to be appointed ambassador to Italy or Germany, he asked an aide to wire either "MACARONI" or "SAUERKRAUT." When it turned out that he had been given the Foreign Ministry, instead, the aide improvised and sent "CAVIAR." As late as 1952, Edward Teller actually transmitted the highly secret news of the hydrogen bomb's success to his old colleagues at Los Alamos via a commercial telegraph reading, "It's a boy."