Authorization using the client application

Question

PHP

The task was to implement authorization on the site through a special key, this is a text file with a specific key. We decided to write a client application that would be installed on the user's machine and listen to some port during authorization, the server would send a request to this application, it would simply take the key on the user's machine and send it in response. It is desirable to implement all this in c#. In this case, there should be no problems with NATs! can anyone come across what you advise?

Answer 1

Why shouldn't the application register itself on the server at startup?...
You can do hole punching .
Key exchange - Diffie-Hellman.
Encryption - AES or Blowfish.

Answer 2

There may be several keys on one machine, so the problem may arise. The idea is that the application should always hang in the background, and even better if as a service.

Answer 3

In order not to produce a topic, I'll ask here. If I start listening to a port in the console application, the firewall asks if you trust it, and if you do, then the port and the machine can be accessed via the Internet. But if the port is opened in the service, then this port is only open locally and cannot be accessed via the Internet unless the firewall is turned off. What can be done?

Answer 4

lvl 80 Google Search Adept
Well kag-be here .