NETWORK SYSTEM, SERVER APPARATUS, METHOD FOR DETECTING ILLEGAL USE, AND PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide a network system, etc. which can suitably prevent illegal use by a third person while improving the degree of freedom of a normal user.

SOLUTION: A login information receiving part 203 receives login information sent from a terminal 13. A user authentication part 204 authenticates a user on the basis of relation between information to be authenticated which is included in the login information and authentication information stored in an authentication information storage part 201. When the user is authenticated, a history information storage part 202 stores unique information included in the login information. A terminal authentication part 205 authenticates a terminal 13 on the basis of the history of unique information stored in the history information storage part 202. When the number of different pieces of unique information reaches the number of pieces of information for ten sets of terminals, the terminal authentication part 205 detects illegal use by the third person.

COPYRIGHT: (C)2006,JPO&NCIPI