1. A method for authenticating a computing device, comprising: receiving, at a first computing device, a first identifier for a sensor from a second computing device, wherein the sensor is coupled to the second computing device; determining, at the first computing device, a second identifier for the sensor using a first variance associated with a first subset of pixels from plurality of pixels for the sensor, a second variance associated with a second subset of pixels from the plurality of pixels for the sensor and information associated with each of a third subset of pixels from the plurality of pixels; and determining, at the first computing device, that the first identifier and the second identifier are both associated with the sensor by comparing the first identifier and the second identifier.