Authentication system, in-vehicle authentication system, and authentication method

An in-vehicle authentication system comprising:

• in-vehicle equipment including:
• a first transmitting part configured to communicate in a first frequency band;
• and
• a first transmitting-and-receiving part configured to communicate in a second frequency band;
• a mobile device including:
• a first receiving part configured to communicate in the first frequency band;
• and
• a second transmitting-and-receiving part configured to communicate in the second frequency band,
• wherein the in-vehicle equipment transmits a command in the first frequency band from the first transmitting part, and
• wherein, upon receipt of the command by the first receiving part, the mobile device activates the second transmitting-and-receiving part, generates an authentication key for a response signal, and transmits the response signal including the generated authentication key in the second frequency band, from the mobile device.

An authentication method executed in an authentication system including:

• a first communication device with:
• a first transmitting part configured to communicate in a first frequency band;
• and
• a first transmitting-and-receiving part configured to communicate in a second frequency band;
• and
• a second communication device with:
• a first receiving part configured to communicate in the first frequency band;
• and
• a second transmitting-and-receiving part configured to communicate in the second frequency band,
• wherein the first communication device transmits a command in the first frequency band from the first transmitting part, and
• wherein, upon receipt of the command by the first receiving part, the second communication device activates the second transmitting-and-receiving part, generates an authentication key for a response signal, and transmits the response signal including the generated authentication key in the second frequency band, from the second communication device.