Mutual authentication system and method which checks the authenticity of a device before transmitting authentication data to the device

A mutual authentication method for authenticating a first electronic device and a second electronic device by transmitting authentication data between the first and second electronic devices, comprising the steps of:

• transmitting a first authentication data from the second electronic device to the first electronic device;
• determining the legitimacy of the second electronic device based on the first authentication data transmitted from the second electronic device;
• transmitting a second authentication data, which is used for determining the legitimacy of the first electronic device, from the first electronic device to the second electronic device when the second electronic device is determined to be legitimate by the determining step;
• and
• inhibiting the transmitting of the second authentication data when the second electronic device is determined not to be legitimate by the determining step.

A mutual authentication method for transmitting authentication data between the first and second electronic devices for authenticating with each other, comprising the steps of:

• transmitting first data and first designate data designating first key data to the first electronic device from the second electronic device;
• transmitting second data and second designate data designating second key data to the second electronic device from the first electronic device;
• generating first authentication data based on the second data and the second designate data in the first electronic device;
• generating second authentication data based on the received second data and the second designate data in the second electronic device and transmitting the second authentication data to the first electronic device;
• comparing the first authentication data with the second authentication data transmitted from the second electronic device in the first electronic device;
• generating third authentication data based on the first data and the first designate data in the first electronic device;
• transmitting the third authentication data and third data indicating that the first authentication data coincides with the second authentication data from the first electronic device to the second electronic device when the first authentication data coincides with the second authentication data in the comparing step;
• and
• transmitting fourth data indicating that the first authentication data does not coincide with the second authentication data from the first electronic device to the second electronic device when the first authentication data does not coincide with the second authentication data in the comparing step.

A mutual authentication system for authenticating a first electronic device and a second electronic device by transmitting authentication data between the first and second electronic devices, comprising:

• first transmission means for transmitting a first authentication data from the second electronic device to the first electronic device;
• determination means, provided in the first electronic device, for determining the legitimacy of the second electronic device based on the first authentication data transmitted from the second electronic device by the first transmission means;
• second transmission means for transmitting a second authentication data, which is used for determining the legitimacy of the first electronic device, from the first electronic device to the second electronic device when the second electronic device is determined to be legitimate by the determination means;
• and
• third transmission means for transmitting a determination result data from the first electronic device to the second electronic device when the second electronic device is determined not to be legitimate by the determination means, the determination result data indicating that the second electronic device is not legitimate.

A mutual authentication method for authenticating a first electronic device having a determination means and a second electronic device by transmitting authentication data between the first and second electronic devices, comprising the steps of:

• transmitting a first authentication data from the second electronic device to the first electronic device;
• determining, by the determination means in the first electronic device, the legitimacy of the second electronic device based on the first authentication data transmitted from the second electronic device;
• transmitting a second authentication data, which is used for determining the legitimacy of the first electronic device, from the first electronic device to the second electronic device when the second electronic device is determined to be legitimate by the determining step;
• and
• transmitting a determination result data from the first electronic device to the second electronic device when the second electronic device is determined not to be legitimate by the determining step, the determination result data indicating that the second electronic device is not legitimate.