SECURITY GATEWAY APPARATUS

摘要

A security gateway apparatus (105) has a first encrypting/decrypting part (105a) that determines whether data inputted from a VPN router (102B) has been encrypted. If so, the first encrypting/decrypting part (105a) decrypts the input data and then supplies it to a filtering part (104). Otherwise, the first encrypting/decrypting part (105a) supplies the input data to the filtering part (104) without decryption. In a network (100B) of a location (B), the filtering part (104) is necessarily supplied with data of plain texts, whether the data is to be encrypted and transmitted or it is not encrypted but transmitted as the plain texts. In this way, in the network (100B) of the location (B), the encryption can be used to protect information from leakage or the like, while detections of virus and/or unnecessary contents can be appropriately performed as well.