In a semiconductor device and an information processing system according to one embodiment, an external device generates external device unique information by using a unique code which is a value unique to the semiconductor device, and generates second information by encrypting the first information with the use of the external device unique information. The semiconductor device stores the second information and generates the principal device unique information independently of the external device, with the use of the unique code of the semiconductor device holding the second information, and decrypts the second information with the use of the principal device unique information to obtain the first information.