Long ago, I wanted to create something like this.

There is is a similar upload already, however, this one I believe is a much more modern coding as well as provides a bit more function for your needs and comes with a responsive design as well.

Features:

Built with TailwindCSS 3.0.24 (uses CDN)
Hash generated by timestamp using SHA256 Encryption
USGN & Accesskey Stored in cookies
Username
Data (avatar, user mode, country)


Requirements:
Any webserver like nginx, Apache
PHP 5.1.2+, PHP 7, PHP 8, PECL hash >= 1.1
Modern web-browser in case you using TailwindCSS

Configuration:
Configure index.php:18 line to your own website/domain

How can be used?

1. Users enter their USGN ID
2. They confirm ownership
3. Get redirected and authorized.


Users can logout using logout.php (which destroys cookies)

Changelog:

2022.05.31.

Logout wasn't working properly
Security issue for login
Registration Date support
Country flag and name support
Tailwind updated to 3.0.24 and always using the latest

2021.10.24.

Checking if "accesskey" and "usgn" cookies are set for security reasons. Thanks for @ Skripter5000:
The form now only allows numeric inputs.

Where possible USGN ID is fetched by cookies to save traffic

@ Skripter5000: It can be fixed easily, I might missed that part.

Fixed.

this should not be used ; there is no check if the key is empty, because then the API will always return 1.