Before I get too far into the code question, is c++ the right avenue to go down as far as creating new user and password for a website, and/or authenticating existing users? The majority of the site was written in HTML5, JS, etc. We wanted to use C++ on the server side to authenticate user/pass and create new users for security purposes. If there is an easier way to do it, please advise. If not, I will continue with a question. The site will be fairly large eventually, maybe a social site of sorts (shoot for the stars, right).
If the security really matters, you can build an C++ server that receives HTTPS requests. Other approach may use WebSocket. You can build a WebSocket server using C++ and use its own HTTPS channel for security. Your site can easily connect to the server via WebSocket.
But you may know a thing... your implementation of the application will matter more than the language or library you use.