I heard from GitHub Two-Factor Authentication](https://github.com/blog/1614-two-factor-authentication) nearly a couple of days ago when I was reading my RSS feed. I enabled it and couldn' push to any of my repositories anymore. Learn in this blog post how to fix it.
"Is a process involving two stages to verify the identity of an entity trying to access services in a computer or in a network". Github solves this authentication with sending an SMS to a device which wants to push to their platform.