Authify Login Application implements a very secure way of authentication called "two-factor" or "strong authentication" based on one time passwords.
Instead of authenticating with a simple password each user carries a device ("token") to generate passwords that are valid only one time.
Commercially available tokens look like pocket calculators or key fobs with a display and a keypad. To generate a one-time password (OTP) the user has to enter his PIN into the device.
The authentication is based on two factors: the token device and a PIN ("something you have and something you know").
This is obviously more secure than just a password as an attacker needs to get hold of both the PIN as well as the token device.
In addition eavesdropping on a password that is valid only one time is of no use to the attacker. On the other hand the drawback of strong authentication is that every user has to be provided with a token device this can be quite expensive.
Fortunately smartphones are becoming more and more popular. It stands to reason to use your mobile phone as an authentication token