A semiconductor device is provided. The semiconductor device includes a unique-information generation portion, a detection portion, a memory portion, and a readout portion. The unique-information generation portion operates in a plurality of operation environments to generate unique information. The unique information includes stable information and unstable information. The stable information is constant in the plurality of operation environments, and the unstable information is different in at least two of the plurality of operation environments. The detection portion detects the unstable information. The memory portion stores the unique information and identification information for identifying the unstable information. The readout portion reads out the unique information and the identification information and outputs the unique information and the identification information to an external portion.