One other way: change your password to a temporary one, give it to a trusted friend who changes it. You don't know the password, you can tell the truth to the border agent.

Once you're out of their hands, ask for it back and change it again.

Even if the friend is in the US, they cannot compell her/him to release it easily, US laws apply.

There must be a way to also encrypt the new temporary password with 2 keys so that the trusted friend cannot access your encryped content without your own key.