How to implement Steam login and password authorization in PHP?

Question

PHP

Hello. I'm doing a simple Steam user authorization through PHP.
2 requests are used:
https://steamcommunity.com/login/getrsakey/ and https://steamcommunity.com/login/dologin/ .
The first request takes a pair of login and password and responds with data to encrypt the password.
Everything is fine, but I can not implement the encryption itself. As I understand it, there is RSA encryption, from 3 data that are obtained at the first request.
So please help with encryption, preferably through the official JS, like this link, there is a JS file with encryption: https://steamcommunity-a.akamaihd.net/public/share... .
Unfortunately, I am not familiar with JS at all.
Or maybe someone knows where you can find a ready-made authorization script.
I'm doing an account checker. That is, you just need to check for validity.