# US 11,451,377 B2 · In-vehicle gateway and key management device

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- Number: US 11,451,377 B2
- Document ID: US11451377B2
- Status: Granted
- Kind: B2
- Application number: 16/334,128
- Filed: 2017-09-27
- Published: 2019-08-22
- Granted: 2022-09-20
- Earliest claimed: 2016-10-13
- Assignees: Hitachi Astemo, Ltd.
- Applicants: Hitachi Automotive Systems, Ltd.
- Inventors: Hiroki Yamazaki; Mikio Kataoka
- Web page: https://patentgrep.com/patent/US11451377B2

## CPC

- H04L 9/0822: {using key encryption key}
- H04L 9/08: Key distribution {or management, e.g. generation, sharing or updating, of cryptographic keys or passwords (network architectures or network communication protocols for supporting key management in a packet data network H04L63/06)}
- H04L 9/0891: {Revocation or update of secret information, e.g. encryption key update or rekeying}
- H04L 9/0894: {Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage}
- H04L 9/3215: {using a plurality of channels (network architectures or network communication protocols using different networks H04L63/18)}
- H04L 63/061: {for key exchange, e.g. in peer-to-peer networks (cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838)}
- H04L 63/0869: {for achieving mutual authentication (cryptographic mechanisms or cryptographic arrangements for mutual authentication H04L9/3273)}
- H04L 67/12: specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
- H04W 4/44: for communication between vehicles and infrastructures, e.g. vehicle-to-cloud [V2C] or vehicle-to-home [V2H]
- H04W 12/03: Protecting confidentiality, e.g. by encryption
- H04W 12/041: Key generation or derivation
- H04W 12/0433: Key management protocols
- H04W 12/0471: Key exchange
- H04L 2209/84: Vehicles
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

When updating a key to guarantee security, updating the key during decryption of update data causes an ECU to stop functioning due to a decryption failure. Therefore, an in-vehicle gateway or a key management device of the present invention includes: an update data acquisition unit that receives, from outside a vehicle, update data encrypted with a predetermined key; a key acquisition unit that receives a key from outside the vehicle; a key storage unit in which the key received by the key acquisition unit is stored; and a decryption unit that decrypts the update data acquired by the update data acquisition unit based on the key stored in the storage unit, in which the update data acquisition unit transmits a key acquisition request signal after completion of decryption of the update data by the decryption unit.

## Claims

### Claim 1

An in-vehicle gateway comprising:
an update data acquisition unit that receives, from outside a vehicle, update data encrypted with a predetermined key;
a key acquisition unit that receives a key from outside the vehicle;
a key storage unit in which the key received by the key acquisition unit is stored; and
a decryption unit that decrypts the update data acquired by the update data acquisition unit based on the key stored in the key storage unit,
wherein the key acquisition unit is configured to determine whether a storage unit is in a state in which an update is in progress, and to permit the decryption to resume in response to determining that the update is in progress,
wherein the key acquisition unit confirms the presence or absence of the update data from outside the vehicle in response to a triggering event, the triggering event relating to behavior of the vehicle and being one of activation of the vehicle, stopping of the vehicle, reception of a notification from outside the vehicle, and vehicle periodic processing,
wherein, after the key acquisition unit confirms the presence of the update data in response to the triggering event and after the key is stored in the key storage unit, the decryption unit pauses decryption of the update data in response to an interruption event differing from the triggering event and resumes decryption of the update data when the interruption event ends,
wherein, when the key has not been updated before decryption of the update data, the update data acquisition unit transmits a key acquisition request signal after completion of decryption of the update data by the decryption unit,
wherein, when the key is updated before decryption of the update data is complete, the decryption unit does not pause the decryption in response to the interruption event,
wherein the in-vehicle gateway is configured to revoke and delete the predetermined key in response to an instruction from outside the vehicle.

### Claim 2 (depends on 1)

The in-vehicle gateway according to claim 1, wherein the key acquisition unit updates the key stored in the key storage unit with a key obtained as a result of the key acquisition request signal.

### Claim 3 (depends on 2)

The in-vehicle gateway according to claim 2, wherein the key acquisition unit acquires the key via a route different from a route in which the update data acquisition unit receives the update data.

### Claim 4 (depends on 1)

The in-vehicle gateway according to claim 1, wherein the key acquisition unit acquires the key via a route different from a route in which the update data acquisition unit receives the update data.

### Claim 5 (depends on 1)

The in-vehicle gateway according to claim 1, wherein the interruption event is a loss of power to the in-vehicle gateway.

### Claim 6

A key management device comprising:
an update data acquisition unit that receives, from outside a vehicle, update data encrypted with a predetermined key;
a key acquisition unit that receives a key from outside the vehicle;
a key storage unit in which the key received by the key acquisition unit is stored; and
a decryption unit that decrypts the update data acquired by the update data acquisition unit based on the key stored in the key storage unit,
wherein the key acquisition unit is configured to determine whether a storage unit is in a state in which an update is in progress, and to permit the decryption to resume in response to determining that the update is in progress,
wherein the key acquisition unit confirms the presence or absence of the update data from outside the vehicle in response to a triggering event, the triggering event relating to behavior of the vehicle and being one of activation of the vehicle, stopping of the vehicle, reception of a notification from outside the vehicle, and vehicle periodic processing,
wherein, after the key acquisition unit confirms the presence of the update data in response to the triggering event and after the key is stored in the key storage unit, the decryption unit pauses decryption of the update data in response to an interruption event differing from the triggering event and resumes decryption of the update data when the interruption event ends,
wherein, when the key has not been updated before decryption of the update data, the update data acquisition unit transmits a key acquisition request signal after completion of decryption of the update data by the decryption unit,
wherein, when the key is updated before decryption of the update data is complete, the decryption unit does not pause the decryption in response to the interruption event,
wherein the in-vehicle gateway is configured to revoke and delete the predetermined key in response to an instruction from outside the vehicle.

### Claim 7 (depends on 6)

The key management device according to claim 6, wherein the interruption event is a loss of power to the key management device.

### Claim 8 (depends on 6)

The key management device according to claim 6, wherein the key acquisition unit acquires the key via a route different from a route in which the update data acquisition unit receives the update data.