Terminal device and the authentication device and encryption communication method and certificate providing method

When an application uses a user certificate, decrease the number of candidates for available certificates, to reduce the load on the user's certificate selection. The information terminal 1 communicates with the server 4 via the network 3. You can attach and detach the card 2 to the information terminal 1. Card 2, holds the user certificate and private key, with a cryptographic processing function of the secret key. The information terminal 1 includes a display unit 110, input unit 120, a storage unit 130, the control unit 140, a communication unit 150, the card unit 160. Control unit 140 has a function of managing the use condition of the user certificate and a user certificate obtained from the card 2 via the card unit 160, selects a user certificate available. User certificate selected is used for encrypted communication between the information terminal 1 and the server 4.