Abstract:
An access control system and method is disclosed. The access control system and method includes a terminal and a server. The terminal determines whether to allow access to a requested website and generates a request to the server to download information from the requested website if the terminal determines to allow access. The server determines whether to allow the terminal access to the requested website and provides information from the requested website to the terminal. The server examines the request to determine whether or not the terminal has made a determination whether to allow access to the requested website. The terminal and server work in combination to determine whether to grant access to the requested website. And the server&#39;s determination whether to allow the terminal access is dependent on the server&#39;s determination of whether or not the terminal has made a determination whether to allow access to the requested website.

Description:
The present application is a divisional application of U.S. application Ser. No. 11/087,295, filed on Mar. 22, 2005 now U.S. Pat. No. 7,725,458, which claims priority to Japanese Application No. P2004-085391, filed on Mar. 23, 2004. U.S. application Ser. No. 11/087,295 is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an access control system comprised of a terminal, and a server arranged to receive an access request for access to a site on a network from the terminal and to access the site, and the present invention relates to an access control method in the access control system. 
     2. Related Background Art 
     Presently, quite a lot of contents browsable on the Internet include contents offensive to public order and decency. One of methods of controlling display of such contents is the method by the Platform for Internet Content Selection of W3C (World Wide Web Consortium). In this method, for example, a content creator sets harmful level information on a content created thereby, based on harmful levels as shown in the table of  FIG. 11 . Specific setting methods thereof include, for example, a method of defining and setting a label or labels such as the “PICS-Labels” on each web page. 
     There is another method of controlling access, based on a black list of URLs (Uniform Resource Locators) of sites to which access is rejected, or based on a white list of only URLs of sites to which access is permitted. 
     The access control as described above is often performed by access control apparatus such as a proxy server. There are proposals on the technology of performing access control per individual to access contents, by such access control apparatus (e.g., reference is made to Japanese Patent Application Laid-Open No. 2003-44441). 
     SUMMARY OF THE INVENTION 
     However, when registration and management of URLs of accessible sites or conditions for access are performed per individual, it will result in increasing loads on the server performing the access control and increasing efforts of an administrator of the server. 
     An object of the present invention is therefore to provide an access control system and an access control method capable of reducing the loads on the server and the efforts of the administrator of the server. 
     In order to achieve the above object, an access control system according to the present invention is an access control system comprising a terminal, and a server for receiving an access request for access to a site on a network from the terminal and performing access to the site, wherein the terminal comprises: access request control list holding means for holding at least one of a first list of one or more sites to which a request for access is accepted irrespective of setting of the server and a second list of one or more sites to which an access request for access is prohibited; and access request controlling means for performing a control as follows: where the access request control list holding means holds the first list, the access request controlling means determines whether the access request is an access request for access to a site included in the first list; when the site is determined to be included in the first list, the access request controlling means adds an access permit identifier to the access request; where the access request control list holding means holds the second list, the access request controlling means determines whether the access request is an access request for access to a site included in the second list; when the site is determined to be included in the second list, the access request controlling means prohibits the access request; and wherein the server comprises: access request receiving means for receiving the access request from the terminal; access control list holding means for holding an access control list of one or more sites to which an access request for access is permitted or rejected; and access controlling means for making a determination on whether the access request received by the access request receiving means is accompanied by the access permit identifier, for making a determination on whether the access request is to be permitted or rejected, with reference to the access control list, and for performing an access control corresponding to the access request, based on results of the determinations. 
     In the access control system according to the present invention, when the terminal makes an access request for access to a site listed in the first list, the access permit identifier is added to the access request. On the other hand, when the terminal attempts to make an access request for access to a site listed in the second list, the control to prohibit the access request is carried out. The server makes a determination on whether the access request from the terminal is to be permitted or rejected, with reference to the access control list, and makes a determination on whether the access request is accompanied by the access permit identifier. The server performs the access control, based on the results of these determinations. 
     In this manner, the exceptional access control to the rule uniformly set by the server can be performed for each terminal, without need for individual setting in the server, whereby the loads on the server and the efforts of the administrator of the server can be reduced. 
     More specifically, the access control system is preferably configured so that when the access request is accompanied by the access permit identifier or when permission of access is determined based on the access control list, the access controlling means performs a control to permit access corresponding to the access request. 
     The present invention can also be understood as the invention of the access control method as described below, with like action and effect. 
     An access control method according to the present invention is an access control method in an access control system comprising a terminal holding at least one of a first list of one or more sites to which a request for access is accepted irrespective of setting of a server and a second list of one or more sites to which an access request for access is prohibited; and a server arranged to receive an access request for access to a site on a network from the terminal and to access the site and holding an access control list of one or more sites to which an access request for access is permitted or rejected, the access control method comprising: an access request controlling step wherein the terminal performs a control as follows: where the terminal holds the first list, the terminal determines whether the access request is an access request for access to a site included in the first list; when the site is determined to be included in the first list, the terminal adds an access permit identifier to the access request; where the terminal holds the second list, the terminal determines whether the access request is an access request for access to a site included in the second list; when the site is determined to be included in the second list, the terminal prohibits the access request; an access request receiving step wherein the server receives the access request from the terminal; and an access controlling step wherein the server makes a determination on whether the access request received in the access request receiving step is accompanied by the access permit identifier, the server makes a determination on whether the access request is to be permitted or rejected, with reference to the access control list, and the server performs an access control corresponding to the access request, based on results of the determinations. 
     More specifically, the access control method is preferably arranged so that when the access request is accompanied by the access permit identifier or when permission of access is determined based on the access control list, the server performs a control to permit access corresponding to the access request in the access controlling step. 
     As described above, the present invention enables the exceptional access control to the rule uniformly set by the server, for each terminal, without need for individual setting in the server, and thereby reduces the loads on the server and the efforts of the administrator of the server. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an illustration showing a configuration of an access control system according to an embodiment of the present invention. 
         FIG. 2  is an example of interface screens for preparing a first list and a second list in an embodiment. 
         FIG. 3  is an example of sites for which an access limitation is set by a list on the terminal, and sites for which an access limitation is set on the server, in the first mode of the embodiment. 
         FIG. 4  is a flowchart of processing in a terminal in the first mode of the embodiment. 
         FIG. 5  is a flowchart of processing in a server in an embodiment. 
         FIG. 6  is an example of a request header field of an access request in the first mode of the embodiment. 
         FIG. 7  is another example of sites for which an access limitation is set by a list on the terminal, and sites for which an access limitation is set on the server, in the first mode of the embodiment. 
         FIG. 8  is an example of sites for which an access limitation is set by a list on the terminal, and sites for which an access limitation is set on the server, in the second mode of the embodiment. 
         FIG. 9  is a flowchart of processing in a terminal in the second mode of the embodiment. 
         FIG. 10  is another example of sites for which an access limitation is set by a list on the terminal, and sites for which an access limitation is set on the server, in the second mode of the embodiment. 
         FIG. 11  is an example of a table of harmful levels set for contents. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will be described below with reference to the drawings. 
       FIG. 1  shows a configuration of access control system  1  according to the present embodiment. The access control system  1  is comprised of terminal  10  and server  20 . 
     The terminal  10  sends an access request to the server  20  and makes access to site  30 . Specifically, the terminal  10  is preferably, for example, mobile communication equipment such as a cell phone. It may also be a personal computer, a PDA (Personal Digital Assistant), or the like. The server  20  receives the access request from the terminal  10  and makes access to a plurality of sites  30  through a network N, based on the access request. Specifically, the server  20  is preferably implemented, for example, by information processing equipment consisting of a CPU, a memory and so on, or the like. Specifically, the sites  30  as access targets correspond, for example, to Web servers or the like which provide various contents. Specifically, the network N corresponds, for example, to an Internet network, a mobile telecommunications network, or the like. Although  FIG. 1  shows only one terminal  10  to be connected to the server  20 , a preferred configuration is such that a plurality of terminals exist. 
     Components of terminal  10  and server  20  will be described below. The terminal  10  is comprised of an access request control list holder  12 , an access request controller  14 , an access request part  16 , and an access request result processor  18 . 
     The access request control list holder  12  holds at least one of a first list of sites  30  to which a request for access is accepted irrespective of setting of the server  20 , and a second list of sites  30  to which an access request for access is prohibited. These lists are preferably those specifying the sites  30  by their URLs. Alternatively, means other than URLs may also be used to specify the sites  30 . The details of these lists will be described later. 
     The access request controller  14  reads out the list held in the access request control list holder  12  and performs a control of the access request, based thereon. Specific control contents will be described in the description of processing of the present system. 
     The access request part  16  is controlled by the access request controller  14  so as to send an access request for accessing site  30 , to the server  20 . This access request, specifically, is preferably implemented by transmitting information of a request for access, to the server  20 . 
     The access determinator  32  of the access request controller  14  reads out the list held in the access request control list holder  12  and performs a control of the access request, based thereon. If the site is included in the second list of sites  30 , the access rejector  36  of the access request controller  14  rejects access to the site. Specific control contents will be described in the description of processing of the present system. 
     The access request part  16  is controlled by the access request controller  14 , which generates the request using request generator  34 , so as to send an access request for accessing site  30 , to the server  20 . This access request, specifically, is preferably implemented by transmitting information of a request for access, to the server  20 . 
     The access request receiver  22  receives an access request from the terminal  10 . This reception of the access request, specifically, is preferably carried out by receiving the information of the request for access, transmitted from the terminal  10 . 
     The access control list holder  24  holds an access control list of sites  30  to which the received access request for access is permitted or rejected. The list is preferably one specifying sites  30  by their URLs, as the lists held in the terminal  10  are. The details of these lists will be described later. 
     The access controller  26  retrieves the access request received by the access request receiver  22  and the list held by the access control list holder  24 , and performs a control of the access request, based thereon. Specific control contents will be described in the description of processing of the present system. 
     The access part  28  is controlled by the access controller  26  so as to access a site  30  through the network N. 
     Subsequently, each of the lists held by the terminal  10  and server  20  will be described. 
     The access control list of sites to which an access request for access is permitted or rejected, which is held by the access control list holder  24  of server  20 , is a list for determining whether an arbitrary site is an accessible site or an inaccessible site from the server  20 . 
     The list of sites to which an access request for access is permitted is a list of accessible sites, i.e., a so-called white list. The white list is set, for example, where a provider to provide a service of connection to the network N desires to permit access to its official sites only. 
     On the other hand, the list of sites to which an access request for access is rejected is a list of inaccessible sites, i.e., a so-called black list. The black list is set, for example, where a company or the like prohibits employee&#39;s access to sites remotely related to business, e.g., stock sites, adult sites, charged sites, and so on. Access is permitted to sites not listed in the black list. Only either one of the white list and the black list is normally set in order to avoid inconsistency of setting. 
     The first list held by the access request control list holder  12  of terminal  10  is a list of sites to which exceptional access is desired, irrespective of the setting of the server  20 . Even sites except for the aforementioned official sites set in the white list can be set in the first list, for example, where a user wants to browse Web pages including communications, events, etc. of a school (a setting as schematically shown in  FIG. 3 ). Another possible case is sites to which access should be rejected based on the black list but which are set in the first list, for example, where a user wants to browse Web pages necessary for acquiring information about a client (a setting as schematically shown in  FIG. 7 ). 
     The second list held by the access request control list holder  12  of terminal  10  is a list of sites to which exceptional prohibition of access is desired, irrespective of the setting of the server  20 . Such sites can be set in the second list, for example, where prohibition of access to auction sites, game sites and charged sites is desired even if these sites are among the official sites set in the white list (a setting as schematically shown in  FIG. 8 ). Another possible case is, for example, a case where prohibition of access to chat sites is desired even if the sites are not among the black list (a setting as schematically shown in  FIG. 10 ). 
     These exceptional settings in the terminal  10  can be implemented, for example, by software or the like with an interface screen as shown in  FIG. 2 , displayed on a display means (not shown) of the terminal  10 .  FIG. 2(   a ) is a screen to select exceptional permission or prohibition, and  FIGS. 2(   b ) and ( c ) are screens for entering or selecting sites regarded as exceptions. 
     Subsequently, the processing executed by the access control system  1  in the present embodiment will be described. In the present embodiment, there are some conceivable modes, depending upon settings of the lists held by the terminal  10  and server  20 . The processing will be described for each of the modes. 
     [First Mode] 
     First described is a mode as shown in  FIG. 3 , in which sites to which access is permitted are set on the server  20  (the access control list holder  24  in  FIG. 1  holds the white list) and in which sites to which a request for access is accepted irrespective of the setting of the server  20  are set in addition to the sites listed in the foregoing white list, on the terminal  10 . Let us consider herein a case where an access request is made for access to a site listed in the first list on the terminal  10  (which is a site to which a request for access is accepted irrespective of the setting of the server  20 ). The processing will be described below with reference to the flowcharts of  FIGS. 4 and 5 . In the present mode, the access request control list holder  12  of terminal  10  is assumed not to hold the second list. 
     First, the processing will be described with reference to the flowchart of the processing in the terminal  10  of  FIG. 4 . When the user of the terminal  10  performs an operation for an access request or the like, the processing is initiated. With the operation, data is generated for the access request in the terminal  10  (S 01 ). It is assumed that this data for the access request contains information to specify a site as a target for the access request, e.g., a URL or the like. 
     Subsequently, in the terminal  10  the access request controller  14  retrieves the first list held in the access request control list holder  12 . Then the access request controller  14  reads the information to specify the site as a target for the access request, included in the access request data, e.g., the URL, and then determines whether the URL agrees with one of the sites listed in the first list (S 02 ). In the case of the present mode, the access request is one for access to a site listed in the first list, and a determination of agreement is made. 
     With the determination of agreement, the access request controller  14  adds an access permit identifier to the data of the access request (S 03 ). A specific method of the addition is, for example, a method of defining permission in the request header field of the access request data. In HTTP (Hypertext Transfer Protocol), the general request header field is defined and, as shown in  FIG. 6 , the user agent field (User-Agent) therein contains the information of the user agent having made the access request. For example, there is a method of defining information such as “User-Agent: Access OK” as an access permit identifier in this field. The access permit identifier may be added using another field different from the above. 
     Subsequently, in the terminal  10  the access request part  16  transmits the access request data with the access permit identifier to the server  20 , thereby effecting the access request (S 05 ). 
     When the server  20  receives the access request from the terminal  10 , the processing moves to the server  20 . The processing will be described below with reference to the flowchart of the processing in the server  20  of  FIG. 5 . 
     When the access request is sent from the terminal  10  to the server  20 , the access request receiver  22  in the server  20  receives the access request (S 11 ). 
     Subsequently, the access controller  26  reads the access request thus received, and determines whether the access request is accompanied by the access permit identifier (S 12 ). Specifically, for example, a determination is made by determining whether the information such as “User-Agent: Access OK” is defined in the user agent field of the access request data. Since in the present mode the access request is accompanied by the access permit identifier, a determination of permission is made. 
     With the determination of permission, the access controller  26  controls the access part  28  so as to make access corresponding to the access request. The access part  28  thus controlled accesses the site  30  corresponding to the access request (S 14 ). 
     The site  30  thus accessed transmits data of a result corresponding to the access, to the server  20 , and the access part  28  receives the access result data (S 15 ). 
     Subsequently, the access part  28  delivers the access result data received, to the terminal  10  (S 16 ). 
     When the access result data is transmitted from the server  20  to the terminal  10 , the processing shifts again to the terminal  10 . The processing will be described again with reference to the flowchart of the processing in the terminal  10  of  FIG. 4 . 
     In the terminal  10  the access request result processor  18  receives the access result data as a result of the access request (S 06 ). Subsequently, the access request result processor  18  determines whether the received result is an access prohibit response indicating prohibition of access (S 07 ). Since in the present mode the result is not the access prohibit response, the access request result processor  18  displays the access result data received, i.e., a content of the site corresponding to the access request, on the display means of the terminal  10  (S 08 ). 
     If it is determined at S 02  that the site corresponding to the access request is not included in the first list, the access request is made without addition of the access permit identifier (S 05 ). In that case, it is determined at S 12  of  FIG. 5  in the processing of the server  20  that the access request is not accompanied with the access permit identifier. Thereafter, the access controller  26  of the server  20  retrieves the white list held by the access control list holder  24  and determines whether the access request is one for a site included in the white list (S 13 ). 
     If the access request is determined to be one for a site included in the white list, the processes (S 14 -S 16 ) are carried out in the same manner as in the case where the access request is accompanied by the access permit identifier. If the access request is determined not to be one for a site included in the white list, the access controller  26  transmits data of an access prohibit response indicating that the access request is one for access prohibited, to the terminal  10  (S 17 ). 
     In the terminal  10  to which the data of the access prohibit response was transmitted, the access request result processor  18  determines at S 07  in  FIG. 4  that the received result is the access prohibit response, and provides display of a message that access is prohibited, on the display means of terminal  10  (S 09 ). 
     The processing in the first mode is described above, and the processing is much the same in a mode as shown in  FIG. 7 , in which sites to which access is rejected are set on the server  20  (the access control list holder  24  holds the black list) and in which sites to which a request for access is accepted irrespective of the setting of the server  20 , on the terminal  10  are listed in the black list. The difference is that either the white list or the black list is used to determine whether access is to be permitted or rejected where the access request is not accompanied with the access permit identifier, at S 13  in  FIG. 5 . 
     As described above, since the first list is held, the terminal  10  is allowed to perform the control to make the exceptional access request, regardless of the setting in the server  20 . 
     [Second Mode] 
     Next, as shown in  FIG. 8 , a mode is described, in which sites to which access is permitted are set on the server  20  (the access control list holder  24  holds the white list) and in which sites to which an access request for access is prohibited irrespective of the setting of the server  20 , on the terminal  10  are listed in the foregoing white list. Let us consider herein a case where an access request is made for access to a site listed in the second list on the terminal  10  (which is a site to which an access request for access is prohibited irrespective of the setting of the server  20 ). The processing will be described below with reference to the flowchart of the processing in the terminal  10  of  FIG. 9 . It is assumed in the present mode that the access request control list holder  12  of terminal  10  does not hold the first list. 
     First, the user of the terminal  10  performs an operation for an access request or the like to start the processing. With the operation, data is generated for the access request in the terminal  10  (S 01 ). This data for the access request is assumed to contain information to specify the site as a target for the access request, e.g., a URL or the like. 
     Subsequently, in the terminal  10  the access request controller  14  reads the second list held in the access request control list holder  12 . Then the access request controller  14  reads the information to specify the site as a target for the access request, included in the access request data, e.g., the URL, and determines whether the URL agrees with one of the sites listed in the second list (S 04 ). Since in the case of the present mode the access request is one for access to the site listed in the second list, a determination of agreement is made. 
     With the determination of agreement, the access request controller  14  performs a control to prohibit the access request, over the access request part  16 , and provides display of a message that access is prohibited, on the display means of the terminal  10  (S 09 ). 
     When it is determined at S 04  that the site corresponding to the access request is not included in the second list, the access request is sent to the server  20  (S 05 ), and processing is performed in the same manner in the case where the access request without the access permit identifier is sent to the server  20  in the first mode. In that case, the processing in the server  20  is such that it is determined at S 12  in  FIG. 5  that the access request is not accompanied by the access permit identifier. Thereafter, the access controller  26  of the server  20  reads the white list held by the access control list holder  24  and determines whether the access request is one for a site included in the white list (S 13 ). 
     If the access request is determined to be one for access to a site included in the white list, the access processes (S 14 - 16 ) to the site are carried out in the same manner as in the first mode. If the access request is determined not to be one for access to a site included in the white list, the access controller  26  transmits to the terminal  10  data of an access prohibit response indicating that the access request is one for access prohibited (S 17 ). 
     In the terminal  10  to which the data of the access prohibit response was transmitted, the access request result processor  18  determines that the received result is the access prohibit response at S 09  in  FIG. 9 , and provides display of a message that access is prohibited, on the display means of terminal  10  (S 09 ). 
     The processing in the second mode is described above, and the processing is much the same in a mode as shown in  FIG. 10 , in which sites to which access is rejected are set on the server  20  (the access control list holder  24  holds the black list) and in which sites to which the access request for access is prohibited irrespective of the setting of the server  20 , on the terminal  10  are set in addition to the sites listed in the foregoing black list. The difference is that either the white list or the black list is used to determine whether access is to be permitted where the access request is not accompanied with the access permit identifier, at S 13  in  FIG. 5 . 
     As described above, since the second list is held, the terminal  10  is allowed to perform the control to prohibit the exceptional access request, regardless of the setting of the server  20 . 
     The above embodiment enables the exceptional access control to the rule uniformly set in the server  20 , for each terminal  10 , without need for individual setting in the server  20 , and thus reduces the loads on the server  20  and the efforts of the administrator of the server  20 . 
     In the present embodiment the access request with the access permit identifier is arranged to result in allowing access. However, since whether access is to be made is finally determined on the server  20 , it is also possible to perform a control to reject access even if an access request is accompanied by an access permit identifier. 
     In the first and second modes described above, only one of the first list and the second list is held, but a mode where the both lists are held can be adopted. 
     The disclosure of Japanese Patent Application No. 2004-085391 filed Mar. 23, 2004 including specification, drawings and claims is incorporated herein by reference in its entirety.