To solve the problem wherein it is difficult to determine whether the countermeasure of a DNS server is taken, and to determine whether a legitimate site is accessed.
A content server 20 is provided with a verification information generation means for acquiring a site ID and generating site verification information, and transmits the acquired site ID and the generated site verification information to a network browsing terminal, when accessed from the network browsing terminal 40. The network browsing terminal is provided with a verification information acquisition means and a verification inquiry means; acquires the site ID and the site verification information; and transmits the site ID and the site verification information to a mobile radio terminal 30. A portable carrier authentication server 10 is provided with a site verification means; receives the site ID and the site verification information from the mobile radio terminal; and verifies the site verification information, by using a key for site signature verification. The mobile radio terminal is provided with a verified result output means, receives the verified result of the site verification information from the portable carrier authentication server, and outputs it.
Masao Sekiguchi
Takamasa Nakano