The present disclosure relates to methods, devices, and computer-readable media. In an example there is disclosed a method comprising detecting a state of a computing device, the computing device comprising at least one component. The method may further comprise comparing the detected state with a certified state of the device, the certified state indicating an expected state of the device as certified by a trusted authority. The method may further comprise, in response to the detected state and the certified state being different, identifying a component as a source of the difference and checking, by the trusted authority, whether the component is legitimate or not. The method may further still comprise, in response to the component being legitimate, certifying the difference and updating the certified state.