Control device and control method

A control device, comprising:

• a first processing environment;
• and
• a second processing environment, which is isolated from the first processing environment,
• the first processing environment including:
• a control processing unit configured to execute control processing on a control subject;
• a first storage area for storing data to be used by the control processing unit to control the control subject;
• and
• a verification determination unit configured to determine whether the control processing is to be executed,
• the second processing environment including:
• a second storage area for storing an expected value, which is generated in advance based on the data of the first storage area;
• a verification value generation unit configured to generate a verification value based on the data of the first storage area;
• and
• a verification execution unit configured to verify the data of the first storage area;
• the second storage area being set so as to be accessible only from the second processing environment,
• the verification value generation unit being configured to generate the verification value before the control processing executed by the control processing unit is stopped, and store the generated verification value in the second storage area,
• the verification execution unit being configured to execute comparison processing of comparing the expected value and the verification value before the control processing executed by the control processing unit is activated, and transmit a comparison result indicating a verification success or a verification failure to the verification determination unit included in the first processing environment,
• the verification determination unit being configured to:
• execute, when receiving from the verification execution unit the comparison result indicating the verification success, determination processing of determining that the control processing executed by the control processing unit is to be activated;
• and
• execute, when receiving from the verification execution unit the comparison result indicating the verification failure, determination processing of determining that activation of the control processing executed by the control processing unit is to be stopped.