User Authentication on Smartphones: Focusing on iris biometrics.

A Smartphone is defined as a "mobile phone that can be used as a small computer and that connects to the Internet" [23]. Even though the first smartphone?IBM Simon?was introduced more than two decades ago, the world witnessed an immense evolution of smartphones after the introduction of the first iPhone in 2007 [24]. The current smartphones we carry in our pocket are not only a computer, a phone, a database, an infinite jukebox, a camera, a locator, and all the information in the world on our fingertips but also a personal companion that is a part of our daily life [25]. It is speculated that the smartphone's role as a constant companion, helper, coach, and guardian has only just begun [26].