Authentication processing device and security processing method

The present invention is relative with an authentication apparatus for performing security processing, based on PKI, responsive to the results of processing for authentication for the input information for authentication. The apparatus includes an inputting unit ( 12 ) for entering the information for authentication, an authenticating unit ( 21 ) for authenticating the information for authentication, entered by the inputting unit, a PKI processing unit ( 23 ) for generating a secret key and a public key based on the PKI (Public Key Infrastructure) system to perform preset security processing with the secret key generated, a storage unit ( 24 ), having a write only area in which the secret key generated by the PKI processing unit ( 23 ) is written and which cannot be read out from outside, and a secret key transmitting unit ( 25 ) for directly accessing the write only area of the storage unit ( 24 ) responsive to authentication of the information for authentication by the authentication unit ( 21 ), for transmitting the secret key written in it to the PKI processing unit ( 23 ).