Secure your SSH using two-step authentication on CentOS 7

Running your own Linux server could be very challenging, especially if you want to keep the security of the server on a high level and to protect the personal data as much as possible. During the initial server setup, you may have generated an RSA key pair to connect to the server without using passwords, which is one of the recommended methods to improve the overall security. However, in certain cases this may not be enough, so implementing two-factor authentication should be your next step.