| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a semiconductor device capable of setting and clearing protection under prescribed authority for an on-chip nonvolatile storage device during system debugging and during on-vehicle mounting.SOLUTION: The non-volatile storage device has the following as its transitable security states: an unprotected state (1) in which a rewrite to the non-volatile storage device is enabled when no secret information is set in the non-volatile storage device, and a readout of the stored information is enabled; a protection unlocked state (2) in which, when secret information is set in the non-volatile storage device, a rewrite to the non-volatile storage device is enabled on condition that the result of authentication for the use of the secret information is valid, and a readout of the stored information is permitted; and a protection locked state (3) in which, when secret information is set in the non-volatile storage device, a rewrite to the non-volatile storage device is disabled until the result of authentication for the use of the secret information is verified to be valid, and a readout of the stored information is disabled under a prescribed condition.</p> |
