Abstract: A microprocessor having a processor core includes an information acquisition unit that acquires information encrypted to be used by the processor core, from outside; a decryption unit that decrypts the information with a symmetric key to obtain plain text; and a controller that controls processing on the information acquired by the information acquisition unit based on the symmetric key.

Abstract: A microprocessor includes a first information holding unit, a second information holding unit, and a switching authorization unit. The first information holding unit holds process identification information and authentication information which are associated with each other. The second information holding unit denies access from outside, and holds entry information of a process and the authentication information which are associated with each other. The switching authorization unit allows switching process when the authentication information held in the first information holding unit with the authentication information held in the second information holding unit match.