A scientific calculator was added to the iPhone and iPod touch with versions 2.0 and later of the OS. Among its functions is a random number generator. Press the “Rand” key at the bottom of the screen and Calc displays a random number with 15 decimal places, between 0 and 1. Developers could use this feature to create registration numbers; regular users could use it to create truly random passcodes or passwords. For example, if you wanted to create a random eight digit password, you could hit the Rand button and use the last eight digits of the random number for your password.