Vehicle communication device, method of determining communication abnormality, and storage medium storing program

A method of determining a communication abnormality, comprising:

• receiving a plurality of first data and a plurality of second data respectively corresponding to each of the plurality of first data;
• generating a plurality of third data based on each of the received plurality of first data and an encryption key;
• collecting a group of the plurality of second data received within a predetermined amount of time after start-up of a vehicle;
• comparing each of the group of the plurality of second data received within the predetermined amount of time after the start-up of the vehicle and a corresponding third data of the plurality of third data to authenticate a corresponding first data of the plurality of first data;
• and
• as a result of the comparisons between each of the group of the plurality of second data received within the predetermined amount of time after the start-up of the vehicle and the corresponding third data:
• determining that a device is in an abnormal state if all of the comparisons do not match,
• determining that the device is an attacked state if a part less than all of the comparisons do not match, and
• determining that the device is in a normal state if all of the comparisons do match, wherein
• the abnormal state is not the attacked state, and
• the abnormal state is a state indicating that there is a failure in a communication function of the device or a state indicating an abnormality where the encryption keys do not match.

A non-transitory storage medium storing a program that causes a computer to execute processing, the processing comprising:

• receiving a plurality of first data and a plurality of second data respectively corresponding to each of the plurality of first data;
• generating a plurality of third data based on each of the received plurality of first data and an encryption key;
• collecting a group of the plurality of second data received within a predetermined amount of time after start-up of a vehicle;
• comparing each of the group of the plurality of second data received within the predetermined amount of time after the start-up of the vehicle and a corresponding third data of the plurality of third data to authenticate a corresponding first data of the plurality of first data;
• and
• as a result of the comparisons between each of the group of the plurality of second data received within the predetermined amount of time after the start-up of the vehicle and the corresponding third data:
• determining that a device is in an abnormal state if all of the comparisons do not match,
• determining that the device is an attacked state if a part less than all of the comparisons do not match, and
• determining that the device is in a normal state if all of the comparisons do match, wherein
• the abnormal state is not the attacked state, and
• the abnormal state is a state indicating that there is a failure in a communication function of the device or a state indicating an abnormality where the encryption keys do not match.