Communication mediating apparatus for mediating communication over network

A mediation server mediates a print demand from a client device to a printing device . In order to elude a firewall F/W set between the mediation server and the printing device , the printing device first sends an HTTP request to the mediation server . The mediation server sends back an HTTP response including a print demand to the printing device . Encrypted communication may be established between the client device and the printing device according to the following procedure. The mediation server decrypts cipher data, which is encrypted with a public key by the client device, with a private key, re-encrypts the decrypted data with another private key, and mediates the encrypted data to the printing device . The printing device decrypts the encrypted data with the public key and carries out printing. This arrangement enables the printing device to carry out printing in response to a demand from the client device via respective secure network environments.