An example system may include a processor and a non-transitory machine-readable storage medium storing instructions executable by the processer to transmit, to an edge device, a model to predict an identity of a drawn input; transmit, to the edge device, instructions to cause the edge device to: generate a challenge corresponding to the model, apply the model to a response to the challenge to generate an output, and determine whether the response is generated by a human based on the output; and determine whether to grant the edge device access to a remote resource based on the determination of whether the response is generated by a human.