A method of authenticating a target apparatus by an authentication apparatus that holds a first original key out of a plurality of original keys, and an identifier of the first original key, the target apparatus holding a first value and a plurality of derived keys generated by the plurality of original keys and the first value as inputs to a one-way function, the method includes: the target apparatus selecting a selected key from the plurality of derived keys based on the identifier and generating authentication data based on challenge data and a first generated key based on the selected key; and the authentication apparatus generating an authentication key by the first original key and the first value using the one-way function and generating comparison data based on the challenge data and a second generated key based on the authentication key.