Two factor authentication is a special process which helps increase security and prevent hacking. This type of authentication requires two specific pieces from your users. First, they will need the appropriate digital certificate or token key to gain access to your protect resources. After this certificate, or key, has been verified, they will then be asked to provide the appropriate user ID and password.
You Can Add Two Factor Authentication to Single Sign on Methods
Organizations which prefer to use single sign on authentication methods can easily switch to two factor authentication. You can still assign a single user ID and password to your users for accessing resources. However, in addition to this user ID and password, you will also supply them with either a token key or digital certificate. Most users will not mind having to perform an extra step, as it does not involve having to remember a different user ID or password.