The utility model discloses a follow -on SIM card and mobile terminal and identity identification system, follow -on SIM card include core processing module and the storage module and the serial communication interface that link to each other respectively with this core processing module, storage module is including the procedure storage module, data storage module and the work storage module thatlink to each other with core processing module respectively, the SIM card is equipped with and is used for generating true random number encryption key for the true random number module of encryptingthe authentication key. The utility model discloses well true random number module create true random number encryption key, the SIM cali carries out the encryption with this true random number encryption key to the authentication key, obtains the authentication key of ciphertext form, has also adopted true random number's form with regard to in addition authentication key itself, is generated and accomplish between mobile communication network and SIM card the distribution in advance by mobile communication network for generate and compare the authentication response, further improved the security.