Verifier device and remote attestation system

A remote attestation system comprising:

• a prover device;
• and
• a verifier device,
• wherein:
• the prover device is a device that places and executes software in a memory, comprising:
• a measurement instruction reception unit that receives a measurement instruction from the verifier device;
• a measurement unit that reads the software placed in the memory and calculates a measurement value based on the measurement instruction;
• a measurement result transmission unit that transmits the measurement value as a measurement result to the verifier device;
• an evidence collection instruction reception unit that receives an evidence collection instruction generated by the verifier device based on the measurement result;
• an evidence data collection unit that collects evidence data based on the evidence collection instruction;
• an evidence data transmission unit that transmits the evidence data to the verifier device;
• an additional evidence collection instruction reception unit that receives an additional evidence collection instruction generated by the verifier device based on the evidence data;
• an additional evidence data collection unit that collects additional evidence data based on the additional evidence collection instruction;
• and
• an additional evidence data transmission unit that transmits the additional evidence data to the verifier device;
• the verifier device is a device that verifies integrity of the software executed by the prover device, comprising:
• a measurement instruction generation unit that generates the measurement instruction;
• a measurement instruction transmission unit that transmits the measurement instruction to the prover device;
• a measurement result reception unit that receives the measurement result from the prover device;
• an evidence collection instruction generation unit that generates the evidence collection instruction requesting the evidence data based on the measurement result;
• an evidence collection instruction transmission unit that transmits the evidence collection instruction to the prover device;
• an evidence data reception unit that receives the evidence data from the prover device;
• an address determination unit that determines an address specifying a position of the additional evidence data based on the evidence data;
• an additional evidence data acquisition range determination unit that determines an acquisition range of the additional evidence data to be additionally collected based on the address;
• an additional evidence collection instruction generation unit that generates the additional evidence collection instruction including the acquisition range;
• an additional evidence collection instruction transmission unit that transmits the additional evidence collection instruction to the prover device;
• and
• an additional evidence data reception unit that receives the additional evidence data from the prover device.

A verification method executed by a verifier device in a remote attestation system comprising a prover device and a verifier device, wherein the prover device transmits a measurement result in response to a measurement instruction from the verifier device, and the verifier device transmits an evidence collection instruction requesting evidence data in response to the measurement result from the prover device, and the prover device transmits the evidence data in response to the evidence collection instruction from the verifier device, and the verifier device that has received the evidence data requests additional evidence data, the verification method comprising:

• determining an address specifying a position of the additional evidence data based on the evidence data;
• determining an acquisition range of the additional evidence data to be additionally collected based on the address;
• generating an additional evidence collection instruction including the acquisition range;
• transmitting the additional evidence collection instruction to the prover device;
• and
• receiving the additional evidence data from the prover device.