First time login for a user using API KEY

DiscourseConnect will not work in my case, because at a time either OIDC or Discourse Connect can be used. I tried reverse engineering the discourse api.
The URL is:- Genius

It has following payload:-
{
name: testuser
email: test@xxxxxx.com
username:discoursetestuser3
password_confirmation:2290e67e2f59d6b9a0edbc735cef0e1d
challenge:598d41761746371257a4c89d5ac61260
timezone:Asia/Calcutta
}

I am not able to understand “password_confirmation” and “challenge” parameters. Any idea what is this ?
Both of these parameters are dynamic and there is no fixed value that I can pass. This is random.