Add a token to secure a page

[Nikschavan]

i would like to see a token function like this unsupported plugin:
https://wordpress.org/plugins/post-password-plugin/
Please hide the token after the password protected page is unlocked.
So nobody can copy the URL and share the link that unlook the thank you page.
That would be very nice.

Moved from - https://wordpress.org/support/topic/add-a-token-to-secure-a-page/