Electronic control unit and communication system
A communication system includes a transmission-side electronic control unit and a reception-side electronic control unit. In the transmission-side electronic control unit, one key is selected from a plurality of keys in a memory based on synchronization information which is information synchronized in communication between the transmission-side electronic control unit and the reception-side electronic control unit. Further, a message is generated and a message authentication code (MAC) is generated using the selected key. The message to which the message authentication code is added is transmitted to the reception-side electronic control unit.
1 . An electronic control unit being a transmission-side electronic control unit that transmits a message in a communication system including the transmission-side electronic control unit and a reception-side electronic control unit having a processor and memory configured to receive the message, the electronic control unit being the transmission-side electronic control unit comprising a processor and memory configured to implement:
a key table unit including a plurality of keys;
a key selection unit configured to select one key from the key table unit based on synchronization information which is information synchronized in communication between the transmission-side electronic control unit and the reception-side electronic control unit;
a message generation unit configured to generate the message;
a MAC generation unit configured to generate a message authentication code (MAC) using (i) the key selected by the key selection unit, (ii) the synchronization information, and (iii) the message; and
a transmission unit configured to transmit the message to which the message authentication code is added,
wherein:
the synchronization information includes a freshness value (FV) generated specifically for each Controller Area Network (CAN) ID by each of the transmission-side electronic control unit and the reception-side electronic control unit according to a number of receptions and control information including at least one of (i) information to control a vehicle, (ii) information to control a component included in the vehicle, or (iii) information to control an in-vehicle device;
the electronic control unit being the transmission-side electronic control unit is mounted in the vehicle; and
a key selection rule is defined for each CAN ID, each of freshness values, or each of pieces of the control information, and a key switching timing is determined according to the key selection rule.
2 . The electronic control unit according to claim 1 , wherein:
the synchronization information is time information generated by each of the transmission-side electronic control unit and the reception-side electronic unit.
3 . The electronic control unit according to claim 1 , wherein:
the synchronization information is a nonce which is a disposable random value transmitted from the transmission-side electronic control unit to the reception-side electronic control unit.
4 . The electronic control unit according to claim 1 , wherein:
the key selection unit is configured to select the one key from the key table unit based on a specific bit forming the freshness value.
5 . The electronic control unit according to claim 4 , wherein:
the key selection unit is configured to switch the specific bit forming the freshness value according to each type of the transmitted message.
6 . The electronic control unit according to claim 4 , wherein:
the specific bit forming the freshness value indicates a counted number of times an ignition switch of the vehicle is turned on.
7 . The electronic control unit according to claim 1 , wherein:
the key selection unit is configured to select the one key from the key table unit based on a transmission frequency of the control information transmitted from the electronic control unit being the transmission-side electronic control unit.
8 . The electronic control unit according to claim 1 , wherein the freshness value is generated by counting a number of transmissions for each CAN ID given according to a type of generated control information.
9 . The electronic control unit according to claim 1 , wherein the information synchronized in communication between the transmission-side electronic control unit and the reception-side electronic control unit is synchronized based on the key switching timing determined according to the key selection rule.
10 . An electronic control unit being a reception-side electronic control unit that receives a message in a communication system including a transmission-side electronic control unit have a processor and memory configured to transmit the message and the reception-side electronic control unit, the electronic control unit being the reception-side electronic control unit comprising a processor and memory configured to implement:
a reception unit configured to receive the message transmitted from the transmission-side electronic control unit and a message authentication code (MAC) added to the message;
a key table unit including a plurality of keys;
a key selection unit configured to select one key from the key table unit based on synchronization information which is information synchronized in communication between the transmission-side electronic control unit and the reception-side electronic control unit;
a verification MAC generation unit configured to generate a verification message authentication code (MAC) using (i) the key selected by the key selection unit, (ii) the synchronization information, and (iii) the message; and
a verification unit configured to verify an identity between the message authentication code and the verification message authentication code,
wherein:
the synchronization information includes a freshness value (FV) generated specifically for each Controller Area Network (CAN) ID by each of the transmission-side electronic control unit and the reception-side electronic control unit according to a number of receptions and control information including at least one of (i) information to control a vehicle, (ii) information to control a component included in the vehicle, or (iii) information to control an in-vehicle device;
the transmission-side electronic control unit is mounted in the vehicle; and
a key selection rule is defined for each CAN ID, each of freshness values, or each of pieces of the control information, and a key switching timing is determined according to the key selection rule.
11 . A communication system comprising a transmission-side electronic control unit that transmits a message and a reception-side electronic control unit that receives the message,
wherein each of the transmission-side electronic control unit and the reception-side electronic control unit comprises a processor and memory configured to implement:
a key table unit including a plurality of keys, and
a key selection unit configured to select one key from the key table unit based on synchronization information which is information synchronized in communication between the transmission-side electronic control unit and the reception-side electronic control unit,
wherein the processor and memory of the transmission-side electronic control unit are configured to implement
a message generation unit configured to generate the message,
a MAC generation unit configured to generate a message authentication code (MAC) using (i) the key selected by the key selection unit, (ii) the synchronization information, and (iii) the message, and
a transmission unit configured to transmit the message to which the message authentication code is added,
wherein the processor and memory of the reception-side electronic control unit includes are configured to implement
a reception unit configured to receive the message transmitted from the transmission-side electronic control unit and the message authentication code (MAC) added to the message;
a verification MAC generation unit configured to generate a verification message authentication code (MAC) using (i) the key selected by the key selection unit and (ii) the message; and
a verification unit configured to verify an identity between the message authentication code and the verification message authentication code,
wherein:
the synchronization information includes a freshness value (FV) generated specifically for each Controller Area Network (CAN) ID by each of the transmission-side electronic control unit and the reception-side electronic control unit according to a number of receptions and control information including at least one of (i) information to control a vehicle, (ii) information to control a component included in the vehicle, or (iii) information to control an in-vehicle device;
the transmission-side electronic control unit is mounted in the vehicle; and
a key selection rule is defined for each CAN ID, each of freshness values, or each of pieces of the control information, and a key switching timing is determined according to the key selection rule.
12 . A key selection device in a communication system including a transmission-side electronic control unit having a processor and memory configured to transmit a message and a reception-side electronic control unit having a processor and memory configured to receive the message, the key selection device being implemented by the processor and memory of the transmission-side electronic control unit and comprising:
a key table unit including a plurality of keys;
a key selection unit configured to select one key from the key table unit based on synchronization information which is information synchronized in communication between the transmission-side electronic control unit and the reception-side electronic control unit; and
an output unit configured to output the one key selected by the key selection unit;
wherein:
the synchronization information includes a freshness value (FV) generated specifically for each Controller Area Network (CAN) ID by each of the transmission-side electronic control unit and the reception-side electronic control unit according to a number of receptions and control information including at least one of (i) information to control a vehicle, (ii) information to control a component included in the vehicle, or (iii) information to control an in-vehicle device;
the transmission-side electronic control unit is mounted in the vehicle; and
a key selection rule is defined for each CAN ID, each of freshness values, or each of pieces of the control information, and a key switching timing is determined according to the key selection rule.
13 . A computer-implemented message transmission method executed by a computer in a transmission-side electronic control unit that transmits a message in a communication system including the transmission-side electronic control unit and a reception-side electronic control unit that receives the message, the message transmission method comprising:
selecting one key from a key table unit including a plurality of keys based on synchronization information which is information synchronized in communication between the transmission-side electronic control unit and the reception-side electronic control unit;
generating the message;
generating a message authentication code (MAC) using the selected one key, the synchronization information, and the message; and
transmitting the message and the message authentication code added to the message,
wherein:
the synchronization information includes a freshness value (FV) generated specifically for each Controller Area Network (CAN) ID by each of the transmission-side electronic control unit and the reception-side electronic control unit according to a number of receptions and control information including at least one of (i) information to control a vehicle, (ii) information to control a component included in the vehicle, or (iii) information to control an in-vehicle device;
the transmission-side electronic control unit is mounted in the vehicle; and
a key selection rule is defined for each CAN ID, each of freshness values, or each of pieces of the control information, and a key switching timing is determined according to the key selection rule.
14 . A computer-implemented message reception method executed by a computer in a reception-side electronic control unit that receives a message in a communication system including a transmission-side electronic control unit that transmits the message and the reception-side electronic control unit, the message reception method comprising:
receiving the message transmitted from the transmission-side electronic control unit and a message authentication code (MAC) added to the message; selecting one key from a key table unit including a plurality of keys based on synchronization information which is information synchronized in communication between the transmission-side electronic control unit and the reception-side electronic control unit;
generating a verification message authentication code (MAC) using the selected one key, the synchronization information, and the message; and
verifying an identity between the message authentication code and the verification message authentication code,
wherein:
the synchronization information includes a freshness value (FV) generated specifically for each Controller Area Network (CAN) ID by each of the transmission-side electronic control unit and the reception-side electronic control unit according to a number of receptions and control information including at least one of (i) information to control a vehicle, (ii) information to control a component included in the vehicle, or (iii) information to control an in-vehicle device;
the transmission-side electronic control unit is mounted in the vehicle; and
a key selection rule is defined for each CAN ID, each of freshness values, or each of pieces of the control information, and a key switching timing is determined according to the key selection rule.
15 . A computer-implemented key selection method executed by a computer and used in a communication system including a transmission-side electronic control unit that transmits a message and a reception-side electronic control unit that receives the message, the key selection method comprising:
selecting one key from a key table unit including a plurality of keys based on synchronization information which is information synchronized in communication between the transmission-side electronic control unit and the reception-side electronic control unit; and
outputting the selected one key;
wherein:
the synchronization information includes a freshness value (FV) generated specifically for each Controller Area Network (CAN) ID by each of the transmission-side electronic control unit and the reception-side electronic control unit according to a number of receptions and control information including at least one of (i) information to control a vehicle, (ii) information to control a component included in the vehicle, or (iii) information to control an in-vehicle device;
the electronic control unit being the transmission-side electronic control unit is mounted in the vehicle;
a key selection rule is defined for each CAN ID, each of freshness values, or each of pieces of the control information, and a key switching timing is determined according to the key selection rule.
16 . A non-transitory computer-readable storage medium comprising a message transmission program including instructions executable by a computer, the instructions performing the computer-implemented message transmission method according to claim 13 .
17 . A non-transitory computer-readable storage medium comprising a message reception program including instructions executable by a computer, the instructions performing the computer-implemented message reception method according to claim 14 .
18 . A non-transitory computer-readable storage medium comprising a key selection program including instructions executable by a computer, the instructions performing the computer-implemented key selection method according to claim 15 .
19 . An electronic control unit being a transmission-side electronic unit that transmits an encrypted message in a communication system including the transmission-side electronic control unit and a reception-side electronic control unit having a processor and memory configured to receive the encrypted message, the electronic control unit being the transmission-side electronic control unit comprising a processor and memory configured to implement:
a key table unit including a plurality of keys;
a key selection unit configured to select one key from the key table unit based on synchronization information which is information synchronized in communication between the transmission-side electronic control unit and the reception-side electronic control unit;
a message generation unit configured to generate a message;
an encryption unit configured to generate the encrypted message by using (i) the key selected by the key selection unit and (ii) the message; and
a transmission unit configured to transmit the encrypted message;
wherein:
the synchronization information includes a freshness value (FV) generated specifically for each Controller Area Network (CAN) ID by each of the transmission-side electronic control unit and the reception-side electronic control unit according to a number of receptions and control information including at least one of (i) information to control a vehicle, (ii) information to control a component included in the vehicle, or (iii) information to control an in-vehicle device;
the transmission-side electronic control unit is mounted in the vehicle; and
a key selection rule is defined for each CAN ID, each of freshness values, or each of pieces of the control information, and a key switching timing is determined according to the key selection rule.
20 . An electronic control unit being a reception-side electronic unit that receives an encrypted message in a communication system including a transmission-side electronic control unit having a processor and memory configured to transmit the encrypted message and the reception-side electronic control unit, the electronic control unit being the reception-side electronic control unit comprising a processor and memory configured to implement:
a reception unit configured to receive the encrypted message;
a key table unit including a plurality of keys;
a key selection unit configured to select one key from the key table unit based on synchronization information which is information synchronized in communication between the transmission-side electronic control unit and the reception-side electronic control unit; and
a decryption unit configured to decrypt the encrypted message using the key selected by the key selection unit;
wherein:
the synchronization information includes a freshness value (FV) generated specifically for each Controller Area Network (CAN) ID by each of the transmission-side electronic control unit and the reception-side electronic control unit according to a number of receptions and control information including at least one of (i) information to control a vehicle, (ii) information to control a component included in the vehicle, or (iii) information to control an in-vehicle device;
the transmission-side electronic control unit is mounted in the vehicle; and
a key selection rule is defined for each CAN ID, each of freshness values, or each of pieces of the control information, and a key switching timing is determined according to the key selection rule.