Is it possible to create a custom login page (not the one from Appian) to have user credentials provided by me or admin?

Hello Community, 

I'm looking around to see if it is possible to have my own login system, this is because I'm creating an application that is supposed to show reports with confidential information from the company. 

Now, I know sites are supposed to be public, but I want to somehow show the information to only authorized users through a login system that I create to let users see the information only if they are authorized, but I have not found any information and it seems like it is not possible. 

Has someone been able to create their own login system somehow? If not, do you know if it is possible to create private applications where I can get that achieved?

Thanks in advanced for your time and support. Any insight will be appreciated. 

  Discussion posts and replies are publicly visible