System and method for mutual authentication

1. A mutual authentication system comprising:

a higher-level device and a lower-level device that mutually authenticate each other;

wherein the lower-level device includes:

a control unit configured to control the lower-level device; and

a plurality of slave devices controlled by the control unit;

wherein the control unit includes:

an authentication management unit configured to transmit information to, and receive information from, the higher-level device and each of the plurality of slave devices to mutually authenticate each other;

wherein the plurality of slave devices individually include:

an authentication processing unit configured to create lower-level authentication information for authenticating the higher-level device; and

a memory unit configured to save the lower-level authentication information; and

wherein the authentication management unit includes:

a commanding means for commanding one of the plurality of slave devices to create the lower-level authentication information, according to a request on authentication from the higher-level device;

a sharing means for transmitting the lower-level authentication information received from the above-mentioned one of the slave devices, to the other of the slave devices for the purpose of sharing the lower-level authentication information; and

a transmission means for transmitting the lower-level authentication information, having been shared in all the plurality of slave devices, to the higher-level device.

2. The mutual authentication system according to claim 1 ;

wherein the higher-level device includes a higher-level authentication processing unit for authenticating each of the plurality of slave devices; and

wherein the higher-level authentication processing unit creates higher-level authentication information for authenticating each of the plurality of slave devices, and also creates authentication response information by way of mixing the higher-level authentication information and the transmitted lower-level authentication information.

3. The mutual authentication system according to claim 1 ;

wherein the mutual authentication system is configured to utilize a common key cryptogram method for the higher-level device and the plurality of slave devices to mutually authenticate each other; and

wherein the plurality of slave devices have a secret key that is shared with the higher-level device.

4. A mutual authentication method comprising:

mutual authentication between a higher-level device and each of a plurality of slave devices;

wherein a lower-level device connected to the higher-level device includes:

a control unit configured to control the lower-level device; and

the plurality of slave devices controlled by the control unit;

wherein the control unit includes:

an authentication management unit configured to transmit information to and receive information from, the higher-level device and each of the plurality of slave devices to mutually authenticate each other; and

wherein the mutual authentication method further comprises:

a commanding step by the authentication management unit, in which one of the plurality of slave devices is commanded to create lower-level authentication information, for each of the plurality of slave devices to authenticate the higher-level device, according to a request on authentication from the higher-level device;

a sharing step by the authentication management unit, in which the lower-level authentication information received from the above-mentioned one of the slave devices, is transmitted to the other of the slave devices for the purpose of sharing it; and

a transmission step by the authentication management unit, in which the lower-level authentication information, having been shared in all the plurality of slave devices, is transmitted to the higher-level device.

5. The mutual authentication method according to claim 4 ;

wherein the higher-level device includes a higher-level, authentication processing unit for authenticating each of the plurality of slave devices; and

wherein the mutual authentication method further comprises:

a creating step, in which the higher-level authentication processing unit creates higher-level authentication information for authenticating each of the plurality of slave devices, and also creates authentication response information by way of mixing the higher-level authentication information and the transmitted lower-level authentication information.

6. The mutual authentication method according to claim 5 , further comprising:

a checking step, in which:

a comparison is made between the lower-level authentication information, shared by each of the plurality of slave devices, and the lower-level authentication information included in the authentication response information which is transmitted from the higher-level device; and

then the higher-level authentication information included in the authentication response information is returned to the higher-level device, and the higher-level device makes a comparison between the returned higher-level authentication information and the higher-level authentication information created by the higher-level device for checking the higher-level authentication information.

7. The mutual authentication method according to claim 6 ;

wherein, in the checking step:

each of the plurality of slave devices extracts the higher-level authentication information out of the authentication response information, and the higher-level authentication information is sent to the authentication management unit; and

the authentication management unit returns the higher-level authentication information to the higher-level device if the higher-level authentication information returned from the plurality of slave devices are all identical.

8. The mutual authentication system according to claim 2 ;

wherein the mutual authentication system is configured to utilize a common key cryptogram method is for the higher-level device and the plurality of slave devices to mutually authenticate each other; and

wherein the plurality of slave devices have a secret key that is shared with the higher-level device.

9. The mutual authentication system according to claim 1 ;

wherein a common secret key is stored on each of the higher-level device and the slave devices;

wherein each slave device is configured to encrypt the lower-level information by utilizing the common secret key, so that the lower-level authentication information transmitted to the higher-level device by the transmission means is the encrypted lower-level information.

10. The mutual authentication method according to claim 4 ;

wherein a common secret key is stored on each of the higher-level device and the slave devices;

wherein the mutual authentication method further comprises:

an encrypting step by the authentication management unit, in which the lower-level information is encrypted by utilizing the common secret key; and

wherein the lower-level authentication information transmitted to the higher-level device in the transmission step is the encrypted lower-level information.