Patent ID: 7275158

Claim:
A proxy server, provided between a user terminal and an electronic market server, including a proxy facility for executing authentication and encryption to the electronic market server, instead of the user terminal, in an electronic commercial transaction, comprising: an establishing means for establishing an encrypted communication session between the user terminal and the proxy server, using public and secret keys of the user terminal and an electronic signature both transmitted from the user terminal; a proxy means for executing authentication of a certificate and exchanging a common key X between the proxy server and the electronic market server, using public and secret keys of the electronic market server; an informing means for informing the common key X to the user terminal through the encrypted communication session, which common key X is encrypted by using a common key X′ that is exchanged between the user terminal and the proxy server; and a home card including an encryption managing means for executing the electronic signature and authentication of the certificate in order to execute authentication and exchange of the common key to the electronic market server, said home card cooperating with an access card connected to said user terminal to establish said encrypted communication session and to exchange said common key X′, wherein the home card further includes a logic circuit which enables an access by using a first password input from the user terminal; and a security releasing means for releasing the security for the proxy means by using a second password input from the user terminal, after establishment of the encrypted communication session to the user terminal in which an access was permitted, whereby an encrypted communication is executed directly between the user terminal and the electronic market server by using the common key X that is exchanged between the proxy server and the electronic market server.