Patent attributes
Provided are an identity confirmation method and an identity confirmation system in which it is not necessary to keep a password in memory and in which a credential used for authentication is changed automatically without requiring a user operation. Life log data for the user is received, life log data history is accumulated and managed, the life log data history is referenced to generate a question relating to history that the user is likely to know, the question is transmitted over the Internet to a mobile communication device, an answer to the question relating to history produced by the user and transmitted from the mobile communication device is received over the Internet, the answer from the user is evaluated to determine whether or not the answer is correct, and the success or failure of identification is determined on the basis of the evaluation result.