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 a 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; 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; determining a pixel identifier value for each pixel from the third subset of pixels from the plurality of pixels by receiving the information associated with each of the third subset of pixels for a plurality of sensing environments generating the pixel identifier using the pixel identifier values for each of the plurality of pixels from the first, second and third subset of pixels.