SECURITY DEVICE, MEMORY DEVICE, DATA PROCESSOR AND METHOD

摘要

PROBLEM TO BE SOLVED: To reduce and circuit scale of a security device while securing security. SOLUTION: A read register 115 of a security block 52 of a memory card is brought into a read enable state only when a switch circuit 122 is closed and reading of data not needing concealment is instructed from an external command set into a command register 117. Thus, the external reading of a midway result of an arithmetic operation can be prevented. Furthermore, the authentication commands can be executed only in a prescribed sequence. A comparator circuit 121 detects whether or not the command generated internally through increment is coincident with the external command. When they are coincident, a no error status is set to a status register 118 and the operation continues. When they are dissident, the status with the error is set to the status register 118 and the operation is stopped.