Thank you for response.

>You are missunderstanding the transport encryption(everything related to authentication and pg_hba.conf) and the encrytion of the data at rest

Correct! My questions perhaps implied one is connected to the other whereas they are completely separate. I could have been clearer.

>it means that indices for encrypted columns become useless and are only a waste of cpu time.

are you saying that blunt-force encryption of all data-at-rest renders indexes pointless? Could you provide more context here?

Cheers