[rythie]

This was not a trivial system for it's time. Do you change your ssh keys and certificates every day?

The enigma had a new encryption code for everyday distributed on paper and torn off and destroyed once used. The were different codes and machines used in different branches of the army/navy and the system was updated through the war.

The British didn't get to see the machines or it's method for many years. There were 159 quintillion possible keys and even a 1 million guesses/second it would take 5 million years to guess a code - and don't forget they changed everyday. Also, remember there were no computers to do this, let alone one that that could even remotely approach 1 million operations a second.

So you ought to able to see at the time people were pretty confident it couldn't be broken, and if they hadn't made some mistake in it's use e.g. distributing weather reports, it might have not been.

We are arguably much more complacent than they were vs. their time. It was only recently that perfect forward security became a thing in HTTPS for example (i.e. different key for each connection).