Patent ID: 7937580

Claim:
A mediation apparatus for mediating communication between two client devices connected via a network, the mediation apparatus comprising: a key storage configured to store at least one private key to be used for communication with a client device; a data acquisition module configured to acquire cipher data from a first client device, the cipher data being encrypted with either of a public key corresponding to the private key or a key which is set in communication using the private key and the public key; a data processing module configured to decrypt the cipher data with a corresponding key, the corresponding key being either one of the private key or the key which is set in communication using the private key and the public key, and configured to re-encrypt the decrypted data with the key set in communication using the private key and the public key; a transmission module configured to send the encrypted data to a second client device; and a communication mediation control module; wherein the data processing module is configured to perform at least two types of communication comprising: security communication which utilizes encryption; and standard communication which does not utilize encryption; wherein the data processing module is configured to select to perform either the security communication or the standard communication according to content of data to be communicated; wherein the communication mediation control module stores in advance a table indicating a correspondence between each type of content of data to be communicated and a respective one of the at least two types of communication to be selected by the data processing module; wherein the table indicates whether or not each type of content of data to be communicated requires the security communication; and wherein the data processing module selects to perform either the security communication or the standard communication according by referring to the table and the content of the data to be communicated.