1. A device to use a password by touch-less gesture, the device comprising: two or more ambient light sensors configured to measure light intensity at respective surface locations of the device; and a processor configured to: detect two or more touch-less gestures using light intensity measurements obtained from the two or more ambient lights sensors; verify a password based on the two or more touch-less gestures; and generate a signal to unlock functionality of a first domain in response to verifying the password, the first domain being one of multiple domains specified in the device, wherein the multiple domains include at least a second domain having a different password than the first domain.