1. A device to use a password by touch-less gesture, the device comprising: two or more ambient light sensors arranged at respective surface locations of the device, each of the two or more ambient light sensors configured to measure light intensity at the respective surface location; a first processor configured to execute a password application on the device; and a second processor configured to detect two or more touch-less gestures performed by an object in touch-less communication with the device and define or verify a password based on the two or more touch-less gestures performed by the object in touch-less communication with the device, wherein the second processor detects the two or more touch-less gestures using light intensity measurements obtained from the two or more ambient lights sensors, wherein the second processor verifies the password when a password entry option of the password application is initiated, and responsive to verifying the password, the second processor: generates a signal to unlock functionality of a domain associated with the password, the domain being one of multiple domains specified in the device, each of the multiple domains having a unique password to unlock functionality of each respective domain; and outputs an indication that the domain associated with the password has been unlocked.