Patent ID: 8010787

Claim:
A communication device connected to a communication log device that manages a communication log of packet data transferred over a network and a key managing device that generates a decryption key used to decrypt encrypted packet data, the communication device comprising: a parameter extracting unit that collects the encrypted packet data passing through the communication device and extracts from the encrypted packet data parameters required to generate the decryption key used when the collected packet data is decrypted; a parameter notifying unit that notifies the key managing device of the parameters extracted by the parameter extracting unit, the key managing device storing, for each terminal connected to the communication device, a secret key used by the terminal; a decryption key acquiring unit that acquires from the key managing device the decryption key generated by using both the secret key stored in the key managing device and the parameters given by the parameter notifying unit, the decryption key being generated by the key managing device; a profile information extracting unit that decrypts the collected packet data using the decryption key acquired by the decryption key acquiring unit, analyzes the decrypted packet data, and extracts profile information of the analyzed packet data; and a log transmitting unit that transmits the profile information extracted by the profile information extracting unit and network information related to the network through which the encrypted packet data passes to the communication log device as a communication log.