> if modern email transports don’t count, then isn’t it true that _any_ messaging system could be considered as postcards in that whoever stumbles across the me

> if modern email transports don’t count, then isn’t it true that _any_ messaging system could be considered as postcards in that whoever stumbles across the message contents can read it? You are mistaking transport layer "security" with information security. It's a common, yet potentially grave mistake. Secure communication depends on encryption that is "good enough" so that unauthorised decryption takes too much resources or too much time to be practical, with the only encryption secrets being held by the sender and the receiver. We usually call that approach "End-to-end encryption", or E2EE. It is also something political entities try hard to ban, for obvious reasons, if you consider them mostly being suppressive-authoritarian surveillance state actors. (yes, I am aware of the '5 dollar hackwrench' xkcd comic [1]. If your state actor uses that tactic against you, you have a whole different problem). True E2EE solutions for email exist, but - mostly because virtually no one wanted the extra hassle - they never got adopted widely. In a perfect world, metadata would also be encrypted - or nonexistent at all (there are implementations for that, for example PGP-encrypted messages over bitstream over TOR (I know your 'bitstream address', but all messages get broadcast, e.g. via blockchain, to everyone, and you only pick out those that match your bitstream address. Because you have only your own private PGP key, you can't read the messages to other bitstream addresses, even though you have them). [1] https://xkcd.com/538/ https://xkcd.com/538/