My understanding is that in the US to pay your rent you either send a literal paper check, which had no serious authorisation at all, or your land lord reaches into your account using your bank account number and debits it, without you having to approve.

If not - why do people protect their bank account numbers in the US? In the UK mine is printed on my bank card - anyone can read it off.

It’s like social security numbers in the US - they became passwords when they weren’t supposed to be.

> your land lord reaches into your account using your bank account number and debits it, without you having to approve.

This is how many people pay for rent in Germany (and I strongly suspect elsewhere) as well.

If they take too much, you can get it back with a single click in your bank account.

Quite interesting. In Poland a lot of places have their bank number just on their website if you want to donate something, I don't think you can place a debit like that.

Bank accounts like that often have outgoing direct debits blocked to prevent fraud, as far as I know.

(I don't think there is a registry – this would simply be a bank-side setting to auto-decline all requested direct debits.)

My bank account number is also sometimes freely shared, so I think this is applied at national level (at least in case of Poland)

"I believe you need a specific bank authorization to do ACH withdrawal using only routing and Account#"

No. All you need is an account number and routing number (which are printed on paper checks). The ACH originator is responsible for ensuring the numbers are owned by the payer.