Google Authenticator popularized two-step authentication all over the Internet  and for that alone it deserves a lot of credit. It has numerous shortcomings  however. The user interface is poor -- account names and the timer animation are too small to see comfortably. There is no PIN  which could have been used to store the secret keys encrypted. If somebody steals your phone  they can extract all the secrets from the phone's flash memory. There is no way to back up secrets or transfer them to a second device. Even though I use Google Authenticator all the time  I do so only because there is no good equivalent and trustworthy replacement.
January 23 2017