Method of authenticating authentication-target apparatus by authentication apparatus, authentication apparatus, authentication- target apparatus, and image forming apparatus

An authentication apparatus, comprising:

• a holding unit configured to hold a first original key, from out of a plurality of original keys, and an identifier of the first original key;
• a notification unit configured to notify the identifier of the first original key and challenge data to an authentication-target apparatus;
• a reception unit configured to receive authentication data, a first value, and a second value from the authentication-target apparatus;
• a first generating unit configured to generate an authentication key by taking the first original key and the first value as inputs to a one-way function, generate a generated key based on a third value resulting from performing a predetermined calculation with respect to the second value and the authentication key, and generate comparison data based on the challenge data and the generated key and
• an authentication unit configured to authenticate the authentication-target apparatus by comparing the authentication data and the comparison data.

An image forming apparatus, comprising:

• a holding unit configured to hold a first original key, from out of a plurality of original keys, and an identifier of the first original key;
• a notification unit configured to notify the identifier of the first original key and challenge data to an authentication-target apparatus;
• a reception unit configured to receive authentication data, a first value, and a second value from the authentication-target apparatus
• a first generating unit configured to generate an authentication key by taking the first original key and the first value as inputs to a one-way function, generate a generated key based on a third value resulting from performing a predetermined calculation with respect to the second value and the authentication key, and generate comparison data based on the challenge data and the generated key and
• an authentication unit configured to authenticate the authentication-target apparatus by comparing the authentication data and the comparison data.

An authentication-target apparatus, comprising:

• a holding unit configured to hold a first value and a plurality of derived keys generated by taking the first value and each of a plurality of original keys as inputs to a one-way function;
• a selection unit configured to select a selected key from the plurality of derived keys, based on an identifier, which was notified from an authentication apparatus, of a first original key out of the plurality of original keys;
• a first generating unit configured to generate a generated key based on a third value resulting from performing a predetermined calculation with respect to the second value and the authentication key, and to generate authentication data based on challenge data which was notified from the authentication apparatus, and the generated key;
• and
• a notification unit configured to notify the authentication data, the first value, and the second value to the authentication apparatus.