| 摘要 |
PROBLEM TO BE SOLVED: To conceal a registered password from a system bus by individually performing the registration, update, and deletion of a password and password checking on a rewritable ROM that a keyboard controller has. SOLUTION: The portable computer is equipped with a CPU 1, a sub-CPU which is connected to the CPU 1 through a system bus and performs specific control, and a password storage memory which is placed under the control of the sub-CPU and connected to the sub-CPU through a dedicated signal line and where plural passwords can be registered, and the sub-CPU registers an input password in the memory according to a command issued by the main CPU, checks the adequacy of the input password by referring to the registered password stored in the memory according to a command issued by the main CPU, and conceals the registered password from the system bus.
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