How to create a VK application in PHP?

Question

PHP

Hello. I came across an article on Habré in which a dude describes what you can post on your wall in VK on behalf of someone else's application. And he gives a script in PHP, in which he appears as an old mobile application for Android. In general, I took the source, tested it, so I'm thinking of improving it. Screw the face of Bootstrap + jQuery and take it into service. Right now I'm making a website for myself, it will come in handy in the admin panel.
Here's the actual question.
I don’t really like how VK authorizes applications. That is, I go into the management of my applications, click "Create", specify the base domain, and so on. Then I run the script and of course it works. And what will happen if I give it to a friend and he launches it on his hosting? Will the authorization window open? Will the app ask for permission to access a friend's page? Will VK swear that the script is not running from the domain specified in the settings? What else?
Explain to the fool that how much. I just want to try myself in this niche, but there is no experience.

Answer 1

OAuth 2.0

Answer 2

Vkontakte will return four hundred and one.