Problem definition
The usage of second factor is commonplace in high-security-risk environments, like netbanking, interactions with the government, etc.
The common scenario is to use desktop or a large-screen tablet to access a web interface of the service which, after providing the first factor (usually username and password), asks for a second factor provided by a different device, usually a mobile phone.
This method yields security benefits as it circumvents several problems around passwords: weak passwords, stolen passwords, and keyloggers on a compromised operating system, in the sense that even though they are able to log the passwords they cannot avoid the second factor that is almost always challenge-based.
