To make it possible to achieve collection of a missing information unit in a protected form by supplying the information unit to a 1st information processor from an issuer, and processing the information unit by ciphering or signature or both of them.

An information unit is supplied from an issuer to a first information processor, and the information unit is thereby ciphered by using a 1st key, and this 1st key is supplied in a form of encryption by using a 2nd key. The 2nd key is supplied on a second protected information processor, therefore, it is made possible to decipher the 1st key by using the 2nd key by connecting the 1st information processor and the 2nd protected information processor to each other. With this system, the certificate of the issuer and a private key corresponding thereto are stored in a chip card 1 at the time of issuing the card. Before downloading software, encryption using a session key T is applied to lower rank software components.