Authentication system, authentication device, authentication target device and image forming apparatus

1. An authentication system comprising an authentication device and an authentication target device, wherein

the authentication device includes:

a first memory configured to store one first secret data and one second secret data, the one first secret data to authenticate the authentication target device of a version from a first version that is the same as the authentication device to a second version newer than the first version, the one second secret data to authenticate the authentication target device of a version newer than the second version; and

a first processor, and

the authentication target device includes:

a second memory configured to store a plurality pieces of first target secret data and one second target secret data, the plurality pieces of first target secret data corresponding to each of versions from a third version that is same as the authentication target device to a fourth version older than the third version and for authentication by the authentication device of a version from the third version to the fourth version, the one second target secret data corresponding to each of versions from a fifth version to a sixth version and for authentication by the authentication device of a version from the fifth version to the sixth version, the fifth version being older than the fourth version by one version, the sixth version being older than the fifth version; and

wherein

when the first version is any of the versions from the third version to the fourth version,

the second processor of the authentication target device selects one first target secret data, out of the plurality of pieces of first target secret data, corresponding to the one first secret data among target secret data stored in the second memory, and calculates first response data using the one first target secret data, and

the first processor of the authentication device selects the one first secret data among secret data stored in the first memory, and performs authentication of the authentication target device based on the first response data and the one first secret data, and

when the first version is any of the versions from the fifth version to the sixth version,

the second processor of the authentication target device selects the one second target secret data among the target secret data stored in the second memory, and calculates second response data using the one second target secret data, and

the first processor of the authentication device selects the one second secret data among the secret data stored in the first memory, and performs authentication of the authentication target device based on the second response data and the one second secret data,

wherein

the authentication target device further includes a third memory configured to store signature data corresponding to each of versions from the fifth version to the sixth version;

when the first version is any of the versions from the fifth version to the sixth version, the first processor of the authentication device acquires signature data corresponding to the first version from the authentication target device and verifies the signature data corresponding to the first version;

when verification of the signature data corresponding to the first version is successful, the first processor of the authentication device performs the authentication of the authentication target device based on the second response data and the one second secret data, and

when the first version is any of the versions from the third version to the fourth version, the first processor of the authentication device performs authentication of the authentication target device based on the first response data and the one first secret data without verifying the signature data.

2. An authentication system comprising an authentication device and an authentication target device, wherein

the authentication device includes:

a first memory configured to store one first secret data to authenticate the authentication target device of a first version that is the same as the authentication device and one second secret data to authenticate the authentication target device of a version newer than the first version; and

a first processor, and

the authentication target device includes:

a second memory configured to store a plurality of first target secret data and one second target secret data, the plurality of first target secret data for authentication by the authentication device of a second version that is the same as the authentication target device, the one second target secret data corresponding to each of versions from a third version to a fourth version and for authentication by the authentication device of a version from the third version to the fourth version, the third version being older than the second version by one version, the fourth version being older than the third version; and

a second processor,

wherein

when the first version is a same as the second version,

the second processor of the authentication target device selects one first target secret data, out of the plurality of pieces of first target secret data, corresponding to the one first secret data among target secret data stored in the second memory, and calculates first response data using the one first target secret data, and

the first processor of the authentication device selects the one first secret data among secret data stored in the first memory, and performs authentication of the authentication target device based on the first response data and the one first secret data, and

when the first version is any of the versions from the third version to the fourth version,

the second processor of the authentication target device selects the one second secret data among the secret data stored in the first memory, and calculates second response data using the one second target secret data, and

the first processor of the authentication device selects the one second secret data among the secret data stored in the first memory, and performs authentication of the authentication target device based on the second response data and the one second secret data

wherein

the authentication target device further includes a third memory configured to store signature data corresponding to each of versions from the third version to the fourth version;

when the first version is any of the versions from the third version to the fourth version, the first processor of the authentication device acquires signature data corresponding to the first version from the authentication target device and verifies the signature data corresponding to the first version;

when verification of the signature data corresponding to the first version is successful, the first processor of the authentication device performs the authentication of the authentication target device based on the second response data and the one second secret data, and

when the first version is the second version that is the same as the authentication target device, the first processor of the authentication device performs authentication of the authentication target device based on the first response data and the one first secret data without verifying the signature data.

3. An authentication device comprising:

one or more memories configured to store secret data corresponding to a first authentication key of a first version, secret data corresponding to a second authentication key of the first version, and one or more programs; and

one or more processors,

wherein the one or more programs, when executed by the one or more processors, cause the one or more processors to perform:

communicating with an authentication target device to determine whether the authentication target device is a first authentication target device or a second authentication target device, the first authentication target device storing target secret data corresponding to the first authentication key of the first version and target secret data corresponding to the second authentication key of a second version older than the first version, the second authentication target device storing target secret data corresponding to the first authentication key of a third version newer than the first version and target secret data corresponding to the second authentication key of the first version;

in accordance with a determination that the authentication target device is the first authentication target device,

obtaining first response data based on the target secret data corresponding to the first authentication key of the first version from the authentication target device,

selecting the secret data corresponding to the first authentication key of the first version, and

authenticating the authentication target device based on the secret data corresponding to the first authentication key of the first version and the first response data; and

in accordance with a determination that the authentication target device is the second authentication target device,

obtaining second response data based on the target secret data corresponding to the second authentication key of the first version from the authentication target device,

selecting the secret data corresponding to the second authentication key of the first version, and

authenticating the authentication target device based on the secret data corresponding to the second authentication key of the first version and the second response data,

wherein the one or more programs, when executed by the one or more processors, further cause the one or more processors to perform:

in accordance with the determination that the authentication target device is the second authentication target device,

obtaining signature data from the authentication target device before authenticating the authentication target device,

verifying the signature data, and

when verification of the signature data is successful, authenticating the authentication target device, and

in accordance with the determination that the authentication target device is the first authentication target device,

authenticating the authentication target device without obtaining and verifying the signature data.

4. The authentication device according to claim 3 ,

wherein the one or more programs, when executed by the one or more processors, cause the one or more processors to perform:

in accordance with the determination that the authentication target device is the first authentication target device,

obtaining public data corresponding to the first authentication key of the first version from the authentication target device, the target secret data correspond to the first authentication key of the first version being generated by a one-way function with the secret data corresponding to the first authentication key of the first version and the public data corresponding to the first authentication key of the first version as input; and

authenticating the authentication target device by comparing the first response data with a calculation result based on the secret data corresponding to the first authentication key of the first version and the public data corresponding to the first authentication key of the first version.

5. The authentication device according to claim 3 ,

wherein the one or more programs, when executed by the one or more processors, cause the one or more processors to perform:

in accordance with the determination that the authentication target device is the second authentication target device,

obtaining public data corresponding to the second authentication key of the first version from the authentication target device, the target secret data corresponding to the second authentication key of the first version being generated by a one-way function with the secret data corresponding to the second authentication key of the first version and the public data corresponding to the second authentication key of the first version as input; and

authenticating the authentication target device by comparing the second response data with a calculation result based on the secret data corresponding to the second authentication key of the first version and the public data corresponding to the second authentication key of the first version.

6. The authentication device according to claim 5 , wherein the signature data is message-recovery type signature data of data including at least one of an identifier of the secret data corresponding to the second authentication key of the first version and the public data corresponding to the second authentication key of the first version.

7. An image forming apparatus configured to mount a cartridge, comprising:

one or more memories configured to store secret data corresponding to a first authentication key of a first version, secret data corresponding to a second authentication key of the first version, and one or more programs; and

one or more processors,

wherein the one or more programs, when executed by the one or more processors, cause the one or more processors to perform:

when the cartridge is mounted, communicating with the cartridge to determine whether the cartridge is a first cartridge or a second cartridge, the first cartridge storing target secret data corresponding to the first authentication key of the first version and target secret data corresponding to the second authentication key of a second version older than the first version, the second cartridge storing target secret data corresponding to the first authentication key of a third version newer than the first version and target secret data corresponding to the second authentication key of the first version;

in accordance with a determination that the cartridge is the first cartridge,

obtaining first response data based on the target secret data corresponding to the first authentication key of the first version from the cartridge,

selecting the secret data corresponding to the first authentication key of the first version, and

authenticating the cartridge based on the secret data corresponding to the first authentication key of the first version and the first response data; and

in accordance with a determination that the cartridge is the second cartridge,

obtaining second response data based on the target secret data corresponding to the second authentication key of the first version from the cartridge,

selecting the secret data corresponding to the second authentication key of the first version, and

authenticating the cartridge based on the secret data corresponding to the second authentication key of the first version and the second response data,

wherein

the one or more memories are further configured to store signature data, and

wherein the one or more programs, when executed by the one or more processors, further cause the one or more processors to perform:

in accordance with the determination that the cartridge is the second cartridge,

transmitting the signature data to the cartridge, and

in accordance with the determination that the cartridge is the first cartridge,

not transmitting the signature data to the cartridge.

8. An authentication target device comprising:

one or more memories configured to store a plurality pieces of target secret data respectively corresponding to a plurality of first authentication keys of a first version, target secret data corresponding to a second authentication key of a second version older than the first version, and one or more programs; and

one or more processors,

wherein the one or more programs, when executed by the one or more processors, cause the one or more processors to perform:

communicating with an authentication device to determine whether the authentication device is a first authentication device or a second authentication device, the first authentication device storing secret data corresponding to a first authentication key of the first version among the plurality of first authentication keys of the first version and secret data corresponding to the second authentication key of the first version, the second authentication device storing secret data corresponding to the first authentication key of the second version and secret data corresponding to the second authentication key of the second version;

in accordance with a determination that the authentication device is the first authentication device,

selecting target secret data corresponding to a first authentication key of the first version, which corresponds to the secret data corresponding to the first authentication key of the first version stored in the authentication device, as selected target secret data among the plurality pieces of target secret data respectively corresponding to the plurality of first authentication keys of the first version,

performing a calculation based on the selected target secret data, and

transmitting a result of the calculation to the authentication device, and

in accordance with a determination that the authentication device is the second authentication device,

selecting the target secret data corresponding to the second authentication key of the second version as selected target secret data,

performing a calculation based on the selected target secret data, and

transmitting a result of the calculation to the authentication device,

wherein the one or more memories are further configured to store signature data, and

wherein the one or more programs, when executed by the one or more processors, further cause the one or more processors to perform:

in accordance with the determination that the authentication device is the second authentication device,

transmitting the signature data to the authentication device, and

in accordance with the determination that the authentication device is the first authentication device,

not transmitting the signature data to the authentication device.

9. The authentication target device according to claim 8 , wherein

the one or more memories are further configured to store a plurality of pieces of public data respectively corresponding to the plurality of first authentication keys of the first version and public data corresponding to the second authentication key of the second version;

wherein the one or more programs, when executed by the one or more processors, cause the one or more processors to perform:

in accordance with the determination that the authentication device is the first authentication device,

transmitting, to the authentication device, public data corresponding to a first authentication key of the first version among the plurality pieces of public data respectively corresponding to the plurality of first authentication keys of the first version, wherein the public data corresponding to the first authentication key of the first version corresponds to the secret data corresponding to the first authentication key of the first version stored in the authentication device; and

in accordance with the determination that the authentication device is the second authentication device,

transmitting, to the authentication device, the public data corresponding to the second authentication key of the second version.

10. The authentication target device according to claim 9 , wherein the signature data is message-recovery type signature data of data including at least one of an identifier of the target secret data corresponding to the second authentication key of the second version and the public data corresponding to the second authentication key of the second version.

11. The authentication target device according to claim 8 , wherein the authentication target device is a cartridge that is detachable from an image forming apparatus.