Forged command filtering system and related command authentication circuit

A forged command filtering system, comprising:

• a secure command generating device, arranged to perform a digital signature operation on a selected command to generate a command request;
• a command transmitting device, arranged to receive and transmit the command request;
• a target device arranged to execute a target command corresponding to the command request;
• and
• a command authentication circuit comprising:
• a communication interface, arranged to communicate with the command transmitting device or the target device, and to receive the command request;
• a secure micro-controller, arranged to store a signature verification key of the secure command generating device;
• a control circuit, coupled with the communication interface and the secure micro-controller, arranged to communicate with the command transmitting device or the target device through the communication interface, and arranged to cooperate with the secure micro-controller to authenticate the command request using the signature verification key;
• and
• a storage circuit, coupled with the control circuit, and arranged to store data required for operations of the control circuit;
• wherein the control circuit further instructs the target device to execute the target command corresponding to the command request only if the command request passed authentication processes conducted by the secure micro-controller and the control circuit;
• wherein the secure micro-controller is further arranged to perform a signature algorithm operation on a target command signature corresponding to the command request using the signature verification key to generate a recovered command digest value, and the control circuit is further arranged to generate a target command digest value according to the target command or a corresponding encrypted target command transmitted from the command transmitting device or the target device, and to compare the target command digest value with the recovered command digest value;
• wherein the command request is allowed to pass the authentication processes conducted by the secure micro-controller and the control circuit only if the recovered command digest value is successfully generated by the secure micro-controller while the target command digest value matches with the recovered command digest value.

A command authentication circuit of a forged command filtering system, wherein the forged command filtering system comprises a secure command generating device, a command transmitting device, the command authentication circuit, and a target device;

• the secure command generating device is arranged to perform a digital signature operation on a selected command to generate a command request;
• the command transmitting device is arranged to receive and transmit the command request;
• and the target device is arranged to execute a target command corresponding to the command request;
• the command authentication circuit comprising:
• a communication interface, arranged to communicate with the command transmitting device or the target device, and to receive the command request;
• a secure micro-controller, arranged to store a signature verification key of the secure command generating device;
• a control circuit, coupled with the communication interface and the secure micro-controller, arranged to communicate with the command transmitting device or the target device through the communication interface, and arranged to cooperate with the secure micro-controller to authenticate the command request using the signature verification key;
• and
• a storage circuit, coupled with the control circuit, and arranged to store date required for operations of the control circuit;
• wherein the control circuit further instructs the target device to execute the target command corresponding to the command request only if the command request passed authentication processes conducted by the secure micro-controller and the control circuit;
• wherein the secure micro-controller is further arranged to perform a message recoverable signature algorithm operation on a target command signature corresponding to the command request using the signature verification key to generate a recovered command coded message containing a recovered command digest value and a recovered command string, and the control circuit is further arranged to extract the target command or a corresponding encrypted target command from the recovered command string, to generate a target command digest value according to the target command or the encrypted target command, and to compare the target command digest value with the recovered command digest value;
• wherein the command request is allowed to pass the authentication processes conducted by the secure micro-controller and the control circuit only if the recovered command coded message is successfully generated by the secure micro-controller while the target command digest value matches with the recovered command digest value.

A command authentication circuit of a forged command filtering system, wherein the forged command filtering system comprises a secure command generating device, a command transmitting device, the command authentication circuit, and a target device;

• the secure command generating device is arranged to perform a digital signature operation on a selected command to generate a command request;
• the command transmitting device is arranged to receive and transmit the command request;
• and the target device is arranged to execute a target command corresponding to the command request;
• the command authentication circuit comprising:
• a communication interface, arranged to communicate with the command transmitting device or the target device, and to receive the command request;
• a secure micro-controller, arranged to store a signature verification key of the secure command generating device;
• a control circuit, coupled with the communication interface and the secure micro-controller, arranged to communicate with the command transmitting device or the target device through the communication interface, and arranged to cooperate with the secure micro-controller to authenticate the command request using the signature verification key;
• and
• a storage circuit, coupled with the control circuit, and arranged to store date required for operations of the control circuit;
• wherein the control circuit further instructs the target device to execute the target command corresponding to the command request only if the command request passed authentication processes conducted by the secure micro-controller and the control circuit;
• wherein the secure micro-controller is further arranged to perform a signature algorithm operation on a target command signature corresponding to the command request using the signature verification key to generate a recovered command digest value, and the control circuit is further arranged to generate a target command digest value according to the target command or a corresponding encrypted target command transmitted from the command transmitting device or the target device, and to compare the target command digest value with the recovered command digest value;
• wherein the command request is allowed to pass the authentication processes conducted by the secure micro-controller and the control circuit only if the recovered command digest value is successfully generated by the secure micro-controller while the target command digest value matches with the recovered command digest value.