User authentication system using IP address and method thereof

A computer-implemented method for authenticating a user, the method comprising:

• receiving a cookie and a URL;
• determining whether or not an IP address of a user having been changed, if changed the cookie being reset by adding the changed IP address to the cookie as a temporary IP address;
• providing a user with a user interface for a re-login process upon detection of the IP address being changed and the URL being required for an authentication, wherein the temporary IP address is added to a valid IP address list in response to detection of a successful re-login process;
• and
• providing a web service.

A method for authenticating a user by IP address check, the method comprising:

• receiving a URL and a session cookie from a client;
• determining whether or not an IP address of the client has been changed based on the session cookie;
• resetting the session cookie, upon detection of the IP address being changed, by adding the changed IP address as a temporary IP address thereto;
• determining whether or not the URL is required to be checking comprising whether the IP address of the client being changed and the URL being required for an authentication;
• requesting a re-login to the client in response to the determination of the URL being required an authentication and the IP address being changed;
• and
• adding the temporary IP address to a valid IP address list in response to detection of the re-login being successful.

A non-transitory computer-readable storage medium comprising an executable program, which when executed, for performing steps for user authentication according to a security level, the steps comprising:

• determining a first valid IP address list of a first class, which records first three octet values of each of IP addresses to generate a group of the IP addresses used by a first user from access log records associated with accessing information activities or login/logout activities of the first user;
• determining a first valid IP address list of a second class, which records first four octet values of each of IP addresses to generate a group of the IP addresses used by a second user from access log records of the second user;
• determining a second valid IP address list of a first class, which records first three octet values of each of IP addresses to generate a group of the IP addresses used by a second user, the second valid IP address comprising a temporary IP address which is added into the first valid IP address list of the first class in response to detection of a successful re-login process;
• and
• determining a second valid IP address list of a second class, which records first four octet values of each of IP addresses to generate a group of IP addresses the second valid IP address comprising a temporary IP address which is added into the first valid IP address list of the second class in response to detection of a successful re-login process.