JP4416414B2 - Information processing system, information processing apparatus, connected device, and processing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an information processing technique using an address of Internet Protocol version 6 (hereinafter referred to as IPv6).
[0002]
[Prior art]
With the spread of the Internet, while the Internet has penetrated into daily life, negative factors such as damage caused by inappropriate information and computer viruses have increased. Recently, problems such as access to inappropriate websites during business hours and information leaks from internal to external e-mail, such as decreased productivity and security management due to private use of the Internet within the company, have begun to be pointed out. Yes. In schools and the like, there is a need to restrict Internet access such as preventing students from showing harmful information on the World Wide Web (WWW) and blocking spam mail and spam mail.
[0003]
Conventionally, as a technique for solving such a problem, there is a technique for restricting Internet access by Internet filtering, that is, software. Typical examples include a URL (Unique Resource Locator) check method and a rating / filtering method. The former creates a list of access permission or denial URLs, and controls access to resources by comparing the URL of the request made by the user with the URL of the list. In the latter, a Web page is rated (rated) according to a predetermined standard, and access control is performed with reference to the rating result.
[0004]
[Problems to be solved by the invention]
However, all of the above prior arts perform access control in a terminal using the Internet, and control is performed using a URL or an external resource regardless of the user using the Internet.
[0005]
Therefore, there is a problem that access control is performed for each user or application using the terminal, and further, they cannot be set in detail.
[0006]
The present invention has been made in view of the above problems, and an object thereof is to enable appropriate fine-grained access control.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, an information processing system according to the present invention comprises the following arrangement. That is,
A connected device that can send and receive data; Using IPv6, the Internet protocol An information processing system comprising an information processing device connected to a network via the connection device,
The information processing apparatus includes:
Log in to the information processing device Acquisition means for acquiring user identification information for identifying a user and application identification information for identifying an application;
The acquired user identification information and application identification information IPv6 including IP address is generated by the application output Adding means for adding the generated IP address to the data to be processed;
Transmission means for transmitting data to which the IP address is added by the adding means to the connected device,
The connection device is
The IP address added to the data transmitted from the transmission means The user identification information and the application identification information are extracted from the user identification information and application identification information, And an access control means for controlling transmission of the data to the network.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0009]
[First Embodiment]
<Overall system configuration>
FIG. 1 is a configuration diagram of the entire system of an information processing system according to an embodiment of the present invention.
[0010]
As shown in FIG. 1, the information processing system of this embodiment is connected so that a computer system 100 (information processing device) such as a PC (personal computer) and an access control device 101 (connected device) can communicate with each other. The access control device 101 is connected to an external network 102 such as the Internet. Note that the computer 100 must always go through the access control device 101 in order to connect to the external network 102 such as the Internet.
[0011]
The computer system 100 has various functions including a function for browsing Internet resources, and includes a CPU, a ROM, a RAM, an HDD, and the like.
[0012]
The access control apparatus 101 is a so-called router that relays data flowing on a network to another network, and has a function that is currently generally realized as a router. Further, the access control apparatus 101 manages access rules and is based on access rules. It also has a function to control data flowing through the network. In the example of FIG. 1, the case where the access control apparatus 101 is realized as a dedicated device is illustrated, but the present invention is not limited thereto, and the function can be realized by the computer system 100.
[0013]
The network 102 is a segment network, such as an intranet or the Internet, to which a computer used by a user does not belong.
[0014]
In the embodiment of the present invention, the case where there is one computer system 100 is described for the sake of simplicity, but the same applies to the case where a plurality of computer systems 100 exist in the same segment.
[0015]
<Computer system block diagram>
FIG. 2 is a block diagram showing the configuration of the computer system 100 in the information processing system according to the embodiment of the present invention.
[0016]
Reference numeral 201 in FIG. 2 denotes a central processing unit (hereinafter referred to as a CPU) that controls the computer system.
[0017]
Reference numeral 202 denotes a random access memory (hereinafter referred to as RAM), which functions as a main memory of the CPU 201 and as an execution program area, an execution area of the program, and a data area.
[0018]
Reference numeral 203 denotes a read-only memory (hereinafter referred to as ROM) that stores operation processing procedures of the CPU 201. The ROM 203 includes a program ROM that records basic software (OS) that is a system program for controlling the equipment of the computer system, and a data ROM that stores information necessary for operating the system. An HDD 209 described later may be used instead of the ROM 203.
[0019]
A network interface (NETIF) 204 performs control for performing data transfer between computer systems via the network and diagnoses connection status.
[0020]
Reference numeral 205 denotes a video RAM (VRAM) that develops an image displayed on a screen of a CRT 206, which will be described later, indicating the operating state of the computer system, and controls its display.
[0021]
Reference numeral 206 denotes a display device such as a display. Hereinafter referred to as CRT.
[0022]
Reference numeral 207 denotes a controller for controlling an input signal from an external input device 208 described later.
[0023]
Reference numeral 208 denotes an external input device for accepting operations performed by the computer system user on the computer system. For example, the external input device 208 is a pointing device such as a mouse or a keyboard, and is simply referred to as KB.
[0024]
Reference numeral 209 denotes a hard disk drive (HDD), which is used for storing data such as application programs and image information. The application program in the present embodiment refers to a software program that executes various processing means constituting the present embodiment.
[0025]
An external input / output device 210 inputs / outputs a removable disk (registered trademark) such as a floppy (registered trademark) disk drive or a CD-ROM drive, for example, for reading from the medium of the application program described above. Used. Hereinafter, simply referred to as FDD.
[0026]
Note that application programs and data stored in the HDD 209 may be stored in the FDD 210 and used.
[0027]
Reference numeral 200 denotes an input / output bus (address bus, data bus, and control bus) for connecting the above-described units.
[0028]
<Access control device block diagram>
FIG. 3 is a block diagram showing the configuration of the access control apparatus 101 in the information processing system according to the embodiment of the present invention.
[0029]
When the access control device 101 realizes its function in a computer system, the system block diagram is the same as that of the computer system 100, and therefore the description thereof is omitted here.
[0030]
Here, with reference to FIG. 3, a system block diagram as an example in the case of mounting as a dedicated device will be described. However, the system configuration is not limited to the implementation of the embodiment of the present invention.
[0031]
Reference numeral 301 in FIG. 3 denotes a central processing unit (hereinafter referred to as CPU) that controls the access control apparatus 101.
[0032]
Reference numeral 302 denotes a random access memory (hereinafter referred to as RAM), which functions as a main memory of the CPU 301, and an execution program area, an execution area of the program, and a data area.
[0033]
Reference numeral 303 denotes a read-only memory (hereinafter referred to as ROM) that stores the operation processing procedure of the CPU 301. The ROM 303 includes a program ROM that records basic software (OS), which is a system program that controls the devices of the units in the access control apparatus, and a data ROM that records information necessary for operating the system.
[0034]
Reference numerals 304, 305, and 30N denote network interfaces (NETIF), which perform control for data transfer with a plurality of computer systems and diagnose connection status.
[0035]
Reference numeral 300 denotes an input / output bus (address bus, data bus, and control bus) for connecting the above-described units.
[0036]
<Module configuration and functions>
Next, application modules in the computer system 100 and the access control apparatus 101 in the information processing system according to the embodiment of the present invention will be described with reference to FIG.
[0037]
The application module described below supplies a storage medium storing software program codes for realizing the functions to the system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium in the storage medium. This is achieved by reading and executing the programmed program code.
[0038]
In this case, the program code itself read from the storage medium implements the functions of the present embodiment, and the storage medium storing the program code constitutes the present invention.
[0039]
Further, by executing the program code read by the computer, not only the functions of the present embodiment are realized, but also an OS (operating system) running on the computer based on the instruction of the program code is actually used. This includes a case where part or all of the processing is performed and the function of the present embodiment is realized by the processing.
[0040]
Further, after the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion board is based on the instruction of the program code. It goes without saying that the CPU of the function expansion unit or the like performs part or all of the actual processing and the functions of the present embodiment are realized by the processing.
[0041]
Returning to FIG. The computer system 100 includes a bind list 401 and address binding means 402.
[0042]
The bind list 401 is a table for managing the relationship between the user who logs in to the computer system 100 and the application to be used and the identification information, and uniquely identifies the user, the application, and the identification information with respect to the table. As well as reading, writing, adding, and deleting.
[0043]
The address binding unit 402 has a function of searching, reading, writing, adding, and deleting information in the binding list 401, a function of determining who is currently logged in, and an IP from the identification information. It has a function to limit the use of a specific address for all applications that generate an address and access the IP network.
[0044]
The access control apparatus 101 includes an access rule 411 and access control means 412.
[0045]
The access rule 411 describes logic for determining whether data flowing on a network is relayed or rejected to another network based on identification information, and can be read / written, added, and deleted.
[0046]
The access control unit 412 uses a function for performing search, reading / writing, addition, deletion, and the like on information in the access rule 411, a function for obtaining the identification information from an IP address, and an access rule based on the identification information. Depending on the result of the determination, data flowing on the network is relayed or rejected to other networks, and part of the network layer (third layer) or transport layer (fourth layer) in the OSI reference model. A function that analyzes and forwards and rejects the protocol, a route selection function that determines which route should be forwarded by looking at the network layer address, and a function that discards all data other than the protocol supported by the protocol It is characterized by having.
[0047]
<Bind list>
FIG. 5 is a schematic diagram of the bind list 401 included in the computer system that constitutes the information processing system according to the embodiment of the present invention.
[0048]
The bind list 500 includes two items, a target item 501 and an identification item 502.
[0049]
The bind list 500 can be searched, read / written, added, and deleted for each item, and the identification item 502 is uniquely specified for the target item 501.
[0050]
The target item 501 stores a user ID for logging into the computer system 100 or an application name.
[0051]
The identification item 502 stores identification information, and an IPv6 address used by the computer system 100 in the IP network is generated from the identification information.
[0052]
<System processing flow>
A processing flow of the entire information processing system according to the embodiment of the present invention will be described. When processing is executed in the information processing system according to the present embodiment, the following two setting operations are performed on the system in advance.
[0053]
First, a user who logs in to the computer system 100, identification information used by the user, and application identification information are set for the computer system 100 using the address binding unit 402. The set information is stored in the bind list 401.
[0054]
Secondly, from the computer system 100 or the like, or when the access control apparatus 101 is a computer system, the access control means 412 is used to relay necessary information (data flowing through the network based on the identification information) to another network. Or logic for determining whether to reject). The set information is stored in the access rule 411.
[0055]
First, the flow of processing in the computer system 100 will be described.
[0056]
When a user logs in to the computer system 100, the address binding unit 402 acquires a login user name (user ID) from an OS (Operation System).
[0057]
Using the acquired login user name as a key, the address binding means 402 acquires identification information 1 (identification information used by the login user) from the bind list 401 and holds it.
[0058]
Next, when the user activates an application such as a network browser for browsing Internet resources, the address binding unit 402 acquires the application name from the OS simultaneously with the activation.
[0059]
Using the acquired application name as a key, the address binding unit 402 acquires and holds identification information 2 (application identification information) from the binding list 401.
[0060]
The address binding unit 402 generates an IP address based on the identification information 1 and the identification information 2 held in advance, and delivers the previous IP address to the application. The application will add the above IP address to the IP header portion of the transmission data and use it as the transmission source address.
[0061]
A user uses an application to access a desired resource such as the Internet. At this time, data transmitted from the above application via the NETIF 204 is always transmitted to the external network 102 via the access control apparatus 101.
[0062]
Here, the processing of the access control apparatus 101 when the data transmitted from the NETIF 204 is received by the access control apparatus 101 will be described.
[0063]
The access control means 412 acquires data received by the access control apparatus 101, that is, data transmitted from the computer system 100.
[0064]
The access control unit 412 acquires the transmission source IP address from the IP header portion of the previously acquired data, and extracts identification information from the acquired transmission source IP address.
[0065]
The access control means 412 controls access to the external network based on the extracted identification information. That is, as a result of adapting the identification information to the access rule 411, if the access control unit 412 determines that permission is given, the previous data is sent to the external network 102.
[0066]
On the other hand, if the access control means 412 determines that the access is not permitted, a message is sent to the computer system 100 informing that the access is not permitted.
[0067]
The processing flow of the information processing system will be described in more detail with reference to FIG. FIG. 6 is a conceptual diagram showing a state in which access control is performed using the information processing system according to the embodiment of the present invention. Assuming users A, B, and C who use the information processing system, identification information (user identification information) for identifying each user is set to 0xAB01, 0xAB00, and 0x1201. Also, identification information (application identification information) for identifying applications used by the users A, B, and C is set to 0x1, 0x1, and 0x11, respectively.
[0068]
Further, the user identification information is applied to 65 to 96 bits of IPv6 address having 128 bits, and the application identification information is applied to 97 to 128 bits to create an aggregateable global unicast address. For example, an IP address transmitted from a computer used by user A is as shown in FIG. For the upper 64 bits, for example, data obtained from a router is used.
[0069]
The data in which the generated IP address is added to the IP header portion is transmitted to the access control apparatus 101. In the access control apparatus 101, the access control means 412 analyzes the transmitted data and sets the variable a from the IP address to IP. The identification information is configured with an address of 65 to 80 bits, a variable b of 81 to 96 bits, and a variable c of 97 to 128 bits.
[0070]
Thus, for example, if the variable a is 0xAB, the variable b is 0x1, and the variable c is 0x1, a rule that permits transfer is set in the access rule 411. Will be granted access.
[0071]
The method of mapping the identification information of the user and the application assumed here, the method of assembling the identification information from the IP address, and the rule are examples, and are for simplifying the description.
[0072]
It is obvious that more detailed control is possible by setting a finer IP address and applying rules.
[0073]
As described above, according to the present invention, the address binding unit 402 and the bind list 401 are provided in the computer system 100, and the access control unit 412 and the access rule 411 are provided in the access control apparatus 101, so that one network interface is provided. By assigning a different IP (Internet Protocol, hereinafter referred to as IP) address to each user or application, or both, each user, various applications, and both can be connected to the Internet. It is possible to perform appropriate fine-grained access control when accessing external resources such as.
[0074]
As a result, inappropriate information on the Internet or the like can be restricted, and in particular, inappropriate information can be prevented from being browsed by children. Furthermore, not only children but also businesses can prevent productivity degradation due to inappropriate access to websites during business hours, and it is possible to set security management finely, managing not only users but also systems It will bring great benefits to the side.
[0075]
[Second Embodiment]
In the first embodiment, user identification information (identification information 1) and application identification information (identification information 2) are mapped to an IP address, and access control is performed based on the mapped IP address. In this embodiment, detailed access control for each user and for each application is realized. However, in the present embodiment, access control in consideration of avoiding violation of the privacy of the user will be described.
[0076]
That is, as in the first embodiment, when the user identification information and the application identification information are mapped to the IP address in order to realize fine-grained access control, at the same time, the information is a violation of privacy. It also includes the risk of misuse. Therefore, in the present embodiment, a means for avoiding misuse of information for infringement of privacy when mapping user identification information and application identification information to an IP address will be described.
[0077]
Specifically, instead of an IEEE EUI-64 format address generally used for IPv6 addresses, user identification information and application identification information are mapped using temporary addresses, so that nodes (generally in computer networks) can be used. 1. A connected device that can specify an address.In the example of FIG. 1, it is difficult to identify a computer system 100 connected to the network 102 via the address control device 101), and the information is misused for infringement of privacy. Is to prevent. In the information processing system according to the present embodiment, in addition to performing access control based on the user identification information and the application identification information, the access permission / rejection is also determined depending on whether or not the information is mapped to the temporary address. Switch non-permission. In other words, control is performed so that access is permitted only when the address is mapped to a temporary address that is unlikely to be abused for infringement of privacy.
[0078]
Prior to detailed description of the present embodiment, first, an IEEE EUI-64 format, an IPv6 address generation method, and an address duplication detection method will be described, and then a temporary address used in the present embodiment will be described. And Further, the mechanism of the data link layer will also be mentioned, and finally, details of access control in the information processing system according to the present embodiment will be described.
[0079]
<Description of IEEE EUI-64 format>
Hereinafter, among the contents described in “R. Hinden, S. Deering, IP Version 6 Addressing Architecture, RFC 2373, July 1998”, portions related to the present invention will be described. Refer to RFC 2373 for more details.
[0080]
A typical IPv6 address consists of a prefix and an interface ID, where the prefix is the upper 64 bits and the interface ID is the lower 64 bits. The interface ID is generated as follows based on the 48 bits of the MAC address of the Ethernet (registered trademark) interface.
[0081]
The Ethernet (registered trademark) IEEE identifier (MAC address) is a 6-byte address, and the first 3 bytes are managed and assigned by the IEEE as a manufacturing vendor code. The remaining 3 bytes are managed by each vendor and assigned so that no duplication occurs. FIG. 9 shows the configuration of the Ethernet (registered trademark) MAC address. Each square represents 1-byte (8-bit) data, with 3 bytes from the left being a manufacturing vendor code and the remaining 3 bytes being a code managed by the vendor. Codes managed by vendors are assigned differently for each Ethernet (registered trademark) card, so each Ethernet (registered trademark) card has the world's only address, and data on the Ethernet (registered trademark) Used as an address for sending and receiving.
[0082]
The MAC address (see FIG. 9) of Ethernet (registered trademark) is divided into 3 bytes, and a hexadecimal “FFFE” is sandwiched between them, and the seventh bit from the head is set to 1. This is shown in FIG.
[0083]
C1 ′ in FIG. 10 represents the first bit of C1 in FIG. The 64-bit data having the configuration shown in FIG. 10 is called an interface ID in the IEEE EUI-64 format.
[0084]
<Description of IPv6 address generation method and address duplication detection method>
Next, an IPv6 address generation process that is performed when an IPv6 apparatus (apparatus with an IPv6 address, which corresponds to the computer system 100 in the example of FIG. 1) is turned on or rebooted, and thereafter FIG. 8 shows an operation flowchart of the IPv6 address duplication detection process performed in FIG. This duplication detection process is called DAD (Duplicate Address Detection). Hereinafter, the processing contents will be described along the flow of FIG.
[0085]
Immediately after the IPv6 device is turned on or rebooted in step S801, no address is assigned to the interface. First, the interface ID is determined from the MAC address (see FIG. 9) of Ethernet (registered trademark). (See FIG. 10) is created by the above-described method, and the interface ID is added to the prefix FE80: 0000: 0000: 0000 for the link local address (hereinafter referred to as “tentative”). link-local address). The above is the process of step S802. FIG. 11 shows the configuration of the tenant link-local address.
[0086]
Next, in order to determine whether the tenant link-local address is unique on the link, the IPv6 apparatus performs the following processing. First, configure the initial interface settings. That is, the all-nodes multicast address (FF02 :: 1) and the tentative link-local address of the solid-node multicast address are allocated to the interface. That is, when the interface finds a packet addressed to all-nodes multiaddress, or a packet addressed to the tentative link-local address, the addressed solicited-node multiaddress, it receives it as a packet addressed to its own interface. By assigning the former (all-nodes multicast address), it becomes possible to receive data from other nodes that are already using the tenant link-local address, and the latter (solicited link-local address- By assigning a node multiaddress address, it is possible to detect the presence of other nodes that are simultaneously trying to use the same tenant link-local address. As defined in "RFC 2461 page 91", the solicited link-local address of the specific link-local address is the lower 24 bits of the tenant link-local address with the prefix FF02: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0: 0 1: Data added to FF00 :: / 104, which is a link-local scope multicast address. FIG. 11 and FIG. 12 show their relationship. The above address assignment is step S803 in FIG.
[0087]
Next, create a Neighbor Solicitation message. The Target address of the Neighbor Solicitation message is the tentative link-local address to be determined, the IP Source (source address) is the unspecified address (all 128 bits are 0), and the IP destination target is the destination address t -Set the localized address of the solicited-node multicast address. This Neighbor Solicitation message is sent to DupAddrDetectTransmits Ethernet (registered trademark) at a RetransTimer millisecond interval. Step S804 in FIG. 8 is this process.
[0088]
A node that has received the Neighbor Solicitation message knows that the message is data from a node that is performing DAD if the source address is unspecified address. When a plurality of nodes simultaneously perform DAD for the same address, a plurality of Neighbor Solicitation messages including the same address in the Target Address are received, so that it can be seen that there is an overlap. In that case, no node uses that address. If the received Neighbor Solicitation message is what it sent (because it is looping back a multicast packet), it does not indicate that there are other nodes using or trying to use it.
[0089]
On the other hand, if the node that has received the Neighbor Solicitation message has already used the address included in the Target Address of the message, it returns a multi-weight Neighbor Advertisement. Therefore, if the node that sent the Neighbor Solicitation message receives a multi-cast Neighbor Advertisement, and the target address is the tentative address of the target address (the target of judgment in step S805 of FIG. Are not unique (ie duplicates).
[0090]
As a result of the above DAD, if it is confirmed that the tentative link-local address to be determined is unique on the link (in the case of “No” in step S805 in FIG. 8), the address is set as the link local address to the interface. Assign. This is step S806 in FIG. This completes the DAD. The operations described above can be executed by each of the computer system 100 and the access control apparatus 101 in FIG. 1 (as an IPv6 apparatus).
[0091]
<Temporary address>
Next, temporary address will be described. In "T. Narten, R. Draves, Privacy Extensions for Stateless Address Autoconfiguration in IPv6, RFC3041," addresses of IEEE EUI-64 format addresses and temporary addresses as countermeasures thereof are described. In other words, the interface ID in the IEEE EUI-64 format generated from the MAC address of the Ethernet (registered trademark) interface also functions as an ID for identifying the interface, that is, the IPv6 device, and can be abused for privacy infringement. Therefore, a different interface ID is generated every certain period and used to prevent privacy infringement.
[0092]
The method for creating the temporary address is different from the method for creating the interface ID (see FIG. 10) from the above-described Ethernet (registered trademark) MAC address (see FIG. 9), and uses the MD5 message digest. MD5 is a function that inputs 128 bits and outputs 128 bits. The input 128 bits are composed of the upper 64 bits and the lower 64 bits as follows. The interface ID is the upper 64 bits. A random value 64 bits generated by some method or the lower 64 bits of the previous MD5 calculation result is used as the lower 64 bits of the input 128 bits. The MD5 message digest is calculated using the 128 bits as input, and the upper 64 bits of the calculation result 128 bits are extracted. The 64 bits obtained by setting the seventh bit from the left of the extracted 64 bits to zero is used as an interface ID. The lower 64 bits of the calculation result are recorded for use in the next MD5 calculation.
[0093]
If different interface IDs are generated every certain period according to the above generation method (that is, the interface ID has an attribute that changes every predetermined period), and those interface IDs are used as global addresses, then the IEEE EUI Unlike the case where an address created in the −64 format is used, it is difficult to determine whether or not the nodes are the same, which has an effect of preventing privacy infringement.
[0094]
<Description of data link layer>
Next, the mechanism of the data link layer will be described. In the case of Ethernet (registered trademark), communication in the data link layer located below the IP is packet communication using the MAC address of the Ethernet (registered trademark) interface as an identifier. Therefore, if the information of the data link layer and IP layer of an IPv6 device is available, it is determined whether the IPv6 address used by the IPv6 device is an address created in the IEEE EUI-64 format. If it is not an address created in the IEEE EUI-64 format and the seventh bit from the left is zero, there is a possibility that the address is temporary.
[0095]
<Access control>
The operation of the information processing system according to this embodiment in which an access rule using the above is implemented will be described with reference to FIG.
[0096]
The IPv6 device that has received the Neighbor Solicitation message in the DAD takes out the Target Address in step S1301 and determines whether or not it matches its own address. If they match, the process proceeds to step S1307. The process proceeds to S1302.
[0097]
In step S1302, the lower 64 bits (interface ID) of the Target Address are extracted.
[0098]
In step S1303, it is determined whether or not 25 to 40 bits from the left of the extracted interface ID is 0xFFFE. If it is not 0xFFFE, the process ends. If it is 0xFFFE, the process proceeds to step S1304.
[0099]
In step S1304, it is determined whether or not the seventh bit from the left of the extracted interface ID is 1. If not, the process ends. If it is 1, the process proceeds to step S1305.
[0100]
In step S1305, the source MAC address of the Ethernet (registered trademark) packet including the neighbor solicitation message is extracted.
[0101]
In step S1306, it is determined whether or not the 64-bit data generated in the IEEE EUI-64 format from the source MAC address matches the interface ID extracted in step S1302. If they match, the process proceeds to step S1307, and if they do not match, the process ends.
[0102]
In step S1307, a multicast Neighbor Advertisement is sent.
[0103]
When the above processing is performed, an IPv6 device that intends to use the interface ID generated in the IEEE EUI-64 format receives an amulticast Neighbor Advertisement, so the interface ID cannot be used, but it is generated in the IEEE EUI-64 format. An interface ID different from the interface ID can be used. Therefore, by applying this access rule, it is possible to use an IPv6 address (an address equivalent to an anonymous address) that is not easily abused for infringement of privacy.
[0104]
A specific example of the present embodiment will be described with reference to FIG. In FIG. 14, when identification information is assigned to each of the user and the application, the user identification information is applied to the IPv6 address of 65 to 96 bits, and the application identification information is applied to the IPv6 address of 97 to 128 bits. When identification information is not assigned to each of the user and the application, it is assumed that the interface ID generated from the MAC address in the IEEE EUI-64 format is applied to 65 to 128 bits of the IPv6 address.
[0105]
FIG. 14 shows a case where identification information of users A, B, and C at a certain time is 0xAC01 and 0xAB00, respectively, and identification information of applications used by A, B, and C is 0x1, 0x11, respectively. Yes. In the case of users A and B, since 25 to 40 bits from the left of the interface ID are not 0xFFFE, access is permitted without sending a multi-weight neighbor advertisement from the flowchart of FIG. That is, since the 65th to 128th bits from the left of the address are not interface IDs created in the IEEE EUI-64 format, an external network can be accessed using an address equivalent to an anonymous address. In the case of user C, since an attempt is made to access the outside using an interface ID created in the IEEE EUI-64 format, an amulticast Neighbor Advertisement is sent out and access is prohibited, resulting in abuse of privacy. Never happen. By changing the identification information according to the change in time, it is possible to increase the degree of privacy protection.
[0106]
The method for mapping the identification information of the user and the application assumed here to the IP address, the method for assembling the identification information from the IP address, and the rules are examples, and are for the purpose of simplifying the description. It is obvious that further detailed control is possible by applying another IPv6 address setting and rule.
[0107]
Contrary to the above processing, an access rule that uses only the interface ID generated in the IEEE EUI-64 format can be realized. That is, in step 1306, it is determined whether or not the 64-bit data generated from the source MAC address in the IEEE EUI-64 format matches the interface ID extracted in step S1302. If not, the process proceeds to step S1307. If they match, the process ends. When this process is executed, an IPv6 device that intends to use an interface ID that is not an interface ID generated in the IEEE EUI-64 format receives an amulticast Neighbor Advertisement, so that the interface ID cannot be used. The interface ID generated in the format can be used. Therefore, by applying this access rule, it is possible to use only an IPv6 address including an interface ID created in the IEEE EUI-64 format.
[0108]
As is apparent from the above description, according to the present embodiment, a computer system is provided by performing access control that applies an access rule that controls whether or not to use a network address generated by a specific method. It is possible to perform appropriate fine-grained access control without making the user aware of it while making it difficult to determine whether or not they are the same and preventing privacy infringement.
[0109]
In other words, it is possible to restrict inappropriate information on the Internet and the like, especially for children, protecting them from this information, and to inappropriate websites during business hours not only for children but also for businesses, etc. Productivity can be prevented from being privately used due to access, and it is also possible to prevent the infringement of privacy by grasping the fixed interface ID of the computer system by a third party.
[0110]
Furthermore, it is possible to reduce the security risk for intentionally preventing privacy infringement and to implement fine-grained access control without imposing a heavy burden on the user. Will also bring great benefits.
[0111]
[Third Embodiment]
In the present embodiment, an example of access control combining the second embodiment and the encryption / authentication function will be described. Note that IPsec is taken up as an encryption / authentication function, but is not necessarily limited to IPsec, and other encryption / authentication functions can be used.
[0112]
A configuration including the computer system 100 and the access control apparatus 101 in FIG. 1 will be described as an example. IPsec has a tunnel mode and a transport mode. In the tunnel mode, a path for encrypting communication data or adding data that enables authentication exists in the middle of a path connecting two communicating devices. In other words, the middle section of the route is a mode that functions like a tunnel that conceals communication data (when encrypted). The devices at both ends of the tunnel section and the two devices that communicate with each other are not necessarily different devices. In other words, one end of the tunnel section also serves as one of the communicating devices, but it is not so on the opposite side of the tunnel section. For details, refer to “S. Kent, R. Atkinson, Security Architecture for the Internet Protocol, RFC 2401, November 1998”.
[0113]
An example in which the tunnel mode of the above embodiment is applied will be described. When the computer system 100 in FIG. 1 communicates with a device on the network 102, the access control device 101 functions as one end of the tunnel, and the communication partner device also serves as the other end of the tunnel.
[0114]
In the access control apparatus 101, the IP address and IPsec settings (port, AH, ESP, tunnel mode, pre-shared key, certificate, etc.) of the communication partner are set.
[0115]
In this embodiment, description will be made assuming that data between the communication partner and the access control apparatus 101 is always encrypted by ESP.
[0116]
Furthermore, it is assumed that the access control apparatus 101 is set with an access rule that uses an IPv6 address that is difficult to be abused for infringement of privacy, as described in the second embodiment.
[0117]
When the above settings are made, when the user of the computer system 100 communicates with a communication partner, for example, when accessing with a browser, an IPv6 address that is not easily abused for infringement of privacy is used, and the route is encrypted with ESP. The transmitted data is transmitted / received. Use of an IPv6 address including an interface ID created in the IEEE EUI-64 format, and unencrypted communication data is never transmitted to or received from the communication partner.
[0118]
Therefore, for example, even if the user of the computer system 100 is not familiar with the computer, it communicates with the communication partner in an encrypted state using an IPv6 address that can be protected for privacy without performing complicated settings by itself. it can. In addition, even if the user performs an inadvertent operation or the computer 100 becomes in a state where only the interface ID in the IEEE EUI-64 format can be used due to a failure, in that case, communication with the communication partner is not performed. Since the access control apparatus 101 performs access control, privacy infringement and information leakage due to an accident can be prevented.
[0119]
In addition, even if the user of the computer system 100 attempts to infringe privacy or leak information in detail in the computer, it can be prevented.
[0120]
As an example of a different combination, the access control device 101 applies an access rule that always uses an IPv6 address including an interface ID in the IEEE EUI-64 format, and the access control device 101 is in the IPsec tunnel mode. There may be an example in which ESP is executed as one end and the computer system 100 communicates with a communication partner using AH in the transport mode of IPsec. In this case, for example, the site of the manufacturer of the computer system 100 is the communication partner, and the pre-shared key used in IPsec AH is set in the computer system 100 and sold in advance, and the MAC address of the computer system is also recorded. In such a case, it can be used as access control for realizing safe and reliable access from customers. It goes without saying that other combinations can be implemented with the same configuration.
[0121]
As is clear from the above description, according to this embodiment, the user is aware of fine-grained access control appropriate for the user, such as encryption and authentication of communication data by combining the encryption and authentication functions. It is possible to carry out without making it.
[0122]
This makes it possible to limit inappropriate information on the Internet, etc., especially against children and protect them from such information. It is possible to prevent a decrease in productivity due to private use due to access to the Web site, and to avoid leaking information through communication without encrypting the fixed interface ID of the computer system.
[0123]
In addition, it is possible to prevent intentionally leaking information, so security risks are reduced and fine access control can be implemented without imposing a heavy burden on the user, managing not only the user but also the system. It will also bring great benefits to those who do it.
[0124]
[Fourth Embodiment]
In the present embodiment, an example of an access control system that combines the first embodiment and encryption / authentication functions will be described. As the encryption / authentication function, SSL (Secure Sockets Layer) is taken up. However, the encryption / authentication function is not necessarily limited to SSL, and other encryption / authentication functions can be used.
[0125]
A configuration including the computer system 100 and the access control apparatus 101 in FIG. 1 and FIG. 6 will be described as an example. Using SSL, the computer system 100 can confirm the identity of the Web site by encrypting the Web site on the network 102 in FIG. 1 and the computer system 101.
[0126]
As described in the first embodiment, there are users A, B, and C in the scene of FIG. 6, and the identification information is 0xAC01, 0xAC00, and 0x1201, respectively. The identification information of the applications used by A, B, and C is 0x1, 0x1, and 0x11, respectively.
[0127]
From now on, the user identification information is applied to 65-96 bits of an IPv6 address having 128 bits, and the application identification information is applied to 97-128 bits to create an aggregateable global unicast address.
[0128]
For example, an IP address transmitted from a computer used by A is as shown in FIG. For the upper 64 bits, for example, data obtained from a router is used. The access control means 412 analyzes the transmitted data, and identifies the variable a from the IP address as the IP address value of 65 to 80 bits, the variable b as the value of 81 to 96 bits, and the variable c as the value of 97 to 128 bits. Configure information. For example, if the variable a is 0xAC, the variable b is 0x1, and the variable C is 0x1, by setting a rule that allows SSL communication in the access rule, only A can communicate with SSL. It will be possible. Of course, it is possible to set not for permission but forbidden, and since it has already been described in the first embodiment that the setting can be changed for each application, it goes without saying that those combinations can be applied as an access rule.
[0129]
[Other Embodiments]
Examples of embodiments according to the present invention are listed below.
[0130]
[Embodiment 1] An information processing system comprising a connection device capable of transmitting and receiving data, and an information processing device connectable to a network via the connection device,
The information processing apparatus includes:
Obtaining means for obtaining user identification information for identifying a user and application identification information for identifying an application accessing the network;
Adding means for generating an IP address based on the acquired user identification information and application identification information, and adding the IP address to data transmitted via the application;
The connection device is
Determining means for determining an attribute of an IP address added to the transmitted data;
Recognizing means for analyzing the IP address added to the transmitted data and recognizing the user identification information and the application identification information;
Access control means for controlling access to the network based on the attribute of the IP address and the recognized user identification information and application identification information;
An information processing system comprising:
[0131]
[Embodiment 2] The adding means includes:
The information processing system according to embodiment 1, wherein an IP address having an attribute that changes every predetermined period is generated.
[0132]
[Embodiment 3] The adding means includes:
The information processing system according to embodiment 1, wherein the IP address is generated using a temporary address of IPv6 that is an Internet protocol.
[0133]
[Embodiment 4] The access control means comprises:
2. The information processing according to claim 1, wherein when the determination unit determines that the IP address does not have an attribute that changes every predetermined period, access to the network is not performed. system.
[0134]
[Embodiment 5] The access control means comprises:
If the determination means determines that the IP address is not generated using an IPv6 temporary address, which is an Internet protocol, access to the network is not performed. The information processing system according to aspect 1.
[0135]
[Embodiment 6] The information processing apparatus includes:
A binding list in which an input user ID and the user identification information, and an application and the application identification information are associated with each other, and the acquisition unit includes the binding list based on the input user ID and the application; The information processing system according to claim 1, wherein the user identification information and the application identification information are acquired based on the information.
[0136]
[Embodiment 7] The information processing apparatus includes:
The information processing system according to embodiment 6, further comprising means for searching and changing the bind list.
[0137]
[Embodiment 8] The connection device includes:
The information processing according to claim 1, further comprising a rule relating to access control for the attribute of the IP address, the user identification information, and the application identification information, wherein the access control means makes a determination based on the rule system.
[0138]
[Embodiment 9] The connection device includes:
The information processing system according to embodiment 8, further comprising means for searching and changing the rule.
[0139]
[Embodiment 10] The connection device includes:
The information processing system according to claim 1, wherein when the access control means restricts access to the network, a predetermined message is transmitted to the information processing apparatus.
[0140]
[Embodiment 11] An information processing apparatus connectable to a network via a connection device that can be controlled based on an IP address added to received data,
Obtaining means for obtaining user identification information for identifying a user and application identification information for identifying an application accessing the network;
An adding unit that generates an IP address having an attribute that changes every predetermined period based on the acquired user identification information and application identification information, and adds the IP address to data transmitted through the application When
An information processing apparatus comprising:
[0141]
[Embodiment 12] An information processing apparatus connectable to a network via a connection device that can be controlled based on an IP address added to received data,
Obtaining means for obtaining user identification information for identifying a user and application identification information for identifying an application accessing the network;
Based on the acquired user identification information and application identification information, an IP address is generated using an IPv6 temporary address (temporary address) that is an Internet protocol, and the IP address is transmitted to the data transmitted through the application. An adding means for adding an address;
An information processing apparatus comprising:
[0142]
[Embodiment 13] The embodiment includes a bind list in which an input user ID and the user identification information, and an application and the application identification information are described in association with each other, and the acquisition unit includes the input user ID and the application The information processing apparatus according to claim 11 or 12, wherein the user identification information and the application identification information are acquired based on the binding list.
[0143]
[Embodiment 14] The information processing apparatus according to Embodiment 13, further comprising means for searching and changing the bind list.
[0144]
[Embodiment 15] A connection device for connecting an information processing apparatus capable of transmitting and receiving data to a network,
Determining means for determining an attribute of an IP address added to data transmitted from the information processing apparatus;
Recognizing means for analyzing an IP address added to the transmitted data and recognizing user identification information for identifying a user and application identification information for identifying an application accessing the network;
Access control means for controlling access to the network based on the attribute of the IP address and the recognized user identification information and application identification information;
A connection device comprising:
[0145]
[Embodiment 16] The access control means comprises:
16. The connected device according to claim 15, wherein when the determination unit determines that the IP address does not have an attribute that changes every predetermined period, access to the network is not performed. .
[0146]
[Embodiment 17] The access control means comprises:
If the determination means determines that the IP address is not generated using an IPv6 temporary address that is an Internet protocol, access to the network is not performed. The connection device according to aspect 15.
[0147]
[Embodiment 18] Embodiment 15 includes a rule regarding access control for the attribute of the IP address, the user identification information and the application identification information, and the access control means makes a determination based on the rule. Connected equipment described in 1.
[0148]
[Embodiment 19] The connection device according to Embodiment 18, further comprising means for searching and changing the rule.
[0149]
[Embodiment 20] The connection device according to Embodiment 15, wherein when the access control means restricts access to the network, a predetermined message is transmitted to the information processing apparatus.
[0150]
[Embodiment 21] An information processing method in an information processing apparatus connectable to a network via a connection device capable of access control based on an IP address added to received data,
An acquisition step of acquiring user identification information for identifying a user and application identification information for identifying an application that accesses the network;
An adding step of generating an IP address having an attribute that changes every predetermined period based on the acquired user identification information and application identification information, and adding the IP address to data transmitted through the application When
An information processing method comprising:
[0151]
[Embodiment 22] An information processing method in an information processing apparatus connectable to a network via a connection device capable of access control based on an IP address added to received data,
An acquisition step of acquiring user identification information for identifying a user and application identification information for identifying an application that accesses the network;
Based on the acquired user identification information and application identification information, an IP address is generated using an IPv6 temporary address that is an Internet protocol, and the IP address is transmitted to the data transmitted through the application. Addition process to add address and
An information processing method comprising:
[0152]
[Embodiment 23] The embodiment includes a bind list in which an input user ID and the user identification information, and an application and the application identification information are described in association with each other. 23. The information processing method according to embodiment 21 or 22, wherein the user identification information and the application identification information are acquired from the binding list based on the binding list.
[0153]
[Aspect 24] The information processing method according to Aspect 23, further comprising a step of searching and changing the binding list.
[0154]
[Embodiment 25] An information processing method in a connected device for connecting an information processing apparatus capable of transmitting and receiving data to a network,
A determination step of determining an attribute of an IP address added to data transmitted from the information processing apparatus;
A recognition step of analyzing an IP address added to the transmitted data and recognizing user identification information for identifying a user and application identification information for identifying an application accessing the network;
An access control step of controlling access to the network based on the attribute of the IP address and the recognized user identification information and application identification information;
An information processing method comprising:
[0155]
[Embodiment 26] The access control step comprises:
26. The information processing according to embodiment 25, wherein when the determination step determines that the IP address does not have an attribute that changes every predetermined period, access to the network is not performed. Method.
[0156]
[Embodiment 27] The access control step includes
If it is determined by the determination step that the IP address is not generated using an IPv6 temporary address that is an Internet protocol, access to the network is not performed. The information processing method according to aspect 25.
[0157]
[Embodiment 28] An embodiment 25, comprising a rule relating to access control for the attribute of the IP address, the user identification information, and the application identification information, wherein the access control step makes a determination based on the rule. Information processing method described in 1.
[0158]
[Aspect 29] The information processing method according to Aspect 28, further comprising a step of searching and changing the rule.
[0159]
[Embodiment 30] The information processing method according to embodiment 25, wherein, when access to the network is restricted in the access control step, a predetermined message is transmitted to the information processing apparatus.
[0160]
[Embodiment 31] A control program for realizing the information processing method according to any one of Embodiments 21 to 30 by a computer.
[0161]
【The invention's effect】
As described above, according to the present invention, appropriate fine-grained access control can be performed.
[Brief description of the drawings]
FIG. 1 is a diagram showing a system configuration of an information processing system according to an embodiment of the present invention.
FIG. 2 is a system block diagram of a computer constituting the information processing system according to the embodiment of the present invention.
FIG. 3 is a block diagram of an access control apparatus constituting the information processing system according to the embodiment of the present invention.
FIG. 4 is a diagram showing a module configuration of an information processing system according to an embodiment of the present invention.
FIG. 5 is a conceptual diagram of a bind list included in a computer constituting the information processing system according to the embodiment of the present invention.
FIG. 6 is a conceptual diagram illustrating a state in which access control is performed using the information processing system according to the embodiment of the present invention.
FIG. 7 is a conceptual diagram showing IPv6 addresses used in the information processing system according to the embodiment of the present invention.
FIG. 8 is a flowchart showing a flow of DAD processing in the information processing system according to the embodiment of the present invention.
FIG. 9 is a diagram illustrating a configuration of an Ethernet (registered trademark) MAC address;
FIG. 10 is a diagram illustrating a configuration of an interface ID.
[Fig. 11] Fig. 11 is a diagram illustrating a configuration of a tentative link-local address.
FIG. 12 is a diagram showing a configuration of a tentative link-local address solicited-node multicast address.
FIG. 13 is a diagram showing a flow of processing in an information processing system according to a second embodiment of the present invention.
FIG. 14 is a conceptual diagram illustrating a state in which access control is performed in the information processing system according to the second embodiment of the present invention.
[Explanation of symbols]
100 computer system
101 Access control device
102 network
200 I / O bus
201 CPU
202 RAM
203 Program ROM and data ROM
204 NETIF
205 VRAM
206 CRT
207 KBC
208 KB
209 HDD
210 FDD
300 I / O bus
301 CPU
302 RAM
303 Program ROM / Data ROM
304, 305, 30N NETIF
400 computer system
401 Binding list
402 Address binding means
410 Access control device
411 access list
412 Access control means
500 Bind List
501 Target item
502 Identification information item

Claims (21)

An information processing system comprising a connection device capable of transmitting and receiving data and an information processing device connected to a network via the connection device using IPv6 which is an Internet protocol ,
The information processing apparatus includes:
Acquisition means for acquiring user identification information for identifying a user who has logged into the information processing apparatus and application identification information for identifying an application;
Adding means for generating an IPv6 IP address including the acquired user identification information and application identification information, and adding the generated IP address to data output by the application;
Transmission means for transmitting data to which the IP address is added by the adding means to the connected device,
The connection device is
The user identification information and the application identification information are extracted from the IP address added to the data transmitted from the transmission unit, and the network to the network is extracted based on the extracted user identification information and application identification information. An information processing system comprising access control means for controlling data transmission. The information processing apparatus includes:
A bind list including the user identification information associated with the user ID of the logged-in user and the application identification information associated with the application;
The information processing system according to claim 1, wherein the acquisition unit acquires the user identification information and the application identification information based on the bind list.   2. The information processing system according to claim 1, wherein the access control unit transmits a message indicating that transmission is not permitted to the information processing apparatus when determining that the data should not be transmitted to the network.   The access control means further determines whether or not the IP address added to the data is an IP address generated based on a MAC address, and based on the determination result, the data to the network is determined. The information processing system according to claim 1, wherein transmission is controlled. The access control means performs control so as to prohibit transmission of the data when it is determined that the IP address added to the data is an IP address generated based on a MAC address. Item 5. The information processing system according to Item 4 .   The access control means determines whether or not the IP address added to the data has an attribute that changes every predetermined period. The information processing system according to claim 1, wherein transmission of data is prohibited.   The access control means determines whether or not the IP address added to the data is generated using a temporary address. If the access control means determines that the IP address is not generated using a temporary address, the access control means transmits the data. The information processing system according to claim 1, wherein the information processing system is prohibited.   The information processing system according to claim 1, wherein the adding unit generates an IP address that changes every predetermined period.   The information processing system according to claim 1, wherein the adding unit generates the IP address using a temporary address. An information processing apparatus that connects to a network via a connected device using IPv6, which is an Internet protocol,
Acquisition means for acquiring user identification information for identifying a user who has logged into the information processing apparatus and application identification information for identifying an application;
An adding means for generating an IPv6 IP address including the acquired user identification information and application identification information, and adding the generated IP address to data output by the application;
Transmission means for transmitting data to which the IP address is added by the adding means to the connected device ,
The connected device extracts the user identification information and the application identification information from the IP address added to the data transmitted from the transmission unit, and based on the extracted user identification information and application identification information, An information processing apparatus that controls transmission of the data to the network . A bind list including the user identification information associated with the user ID of the logged-in user and the application identification information associated with the application;
The information processing apparatus according to claim 10 , wherein the acquisition unit acquires the user identification information and the application identification information based on the bind list. The information processing apparatus according to claim 10 , wherein the adding unit further generates an IP address that changes every predetermined period. An IPv6 IP address including user identification information for identifying a user who is logged in to the information processing apparatus and application identification information for identifying an application is generated, and the generated IP address is added to data output by the application. A connected device connected to an information processing apparatus that transmits data with the IP address added thereto ,
Wherein from the IP address added to the data transmitted from the information processing device and the user identification information taken out and the application identification information, based on the corresponding user identification information extracted and application identification information, the network of the data connected device, characterized in that it comprises an access control means for controlling the delivery to. The access control means further determines whether or not the IP address added to the data transmitted from the information processing apparatus is an IP address that changes every predetermined period, and determines a predetermined period 14. The connection device according to claim 13 , wherein if it is determined that the IP address does not change every time, the data transmission is prohibited. An information processing method for controlling an information processing system including a connection device capable of transmitting and receiving data and an information processing device connected to a network via the connection device using IPv6 which is an Internet protocol ,
In the information processing apparatus,
An acquisition step in which an acquisition unit acquires user identification information for identifying a user who has logged in to the information processing apparatus and application identification information for identifying an application;
An adding step of generating an IPv6 IP address including the acquired user identification information and application identification information, and adding the generated IP address to data output by the application;
A transmitting unit that transmits the data to which the IP address is added in the adding step to the connected device; and
In the connection device,
The access control means extracts the user identification information and application identification information from the IP address added to the data transmitted in the transmission step, and based on the extracted user identification information and application identification information , An information processing method comprising: executing an access control step for controlling transmission of the data to a network. A method of controlling an information processing apparatus that connects to a network via a connected device using IPv6, which is an Internet protocol ,
An acquisition step for acquiring user identification information for identifying a user who is logged in to the information processing apparatus and application identification information for identifying an application;
Adding means, an adding step of said generating the acquired user identification information and the IP address of IPv6 including the application identification information, adds the generated IP address to the data output by the application,
A transmission step, comprising: a transmission step of transmitting data to which the IP address is added in the addition step to the connected device ;
The connected device extracts the user identification information and the application identification information from the IP address added to the data transmitted in the transmission step, and based on the extracted user identification information and application identification information, A method for controlling an information processing apparatus, comprising controlling transmission of the data to the network . The control method according to claim 16 , wherein in the adding step, an IP address that changes every predetermined period is further generated. An IPv6 IP address including user identification information for identifying a user who is logged in to the information processing apparatus and application identification information for identifying an application is generated, and the generated IP address is added to data output by the application. , A method of controlling a connected device connected to an information processing device that transmits data with the IP address added thereto ,
Access control means, the extraction from the IP address added to the data transmitted from the information processing device and the user identification information and the application identification information, based on the corresponding user identification information extracted and application identification information An access control step of controlling transmission of the data to the network is provided. In the access control step, it is further determined whether or not the IP address added to the data transmitted from the information processing apparatus is an IP address that changes every predetermined period. 19. The method for controlling a connected device according to claim 18 , wherein if it is determined that the IP address does not change every time, the transmission of the data is prohibited. A computer-readable storage medium storing a control program for causing a computer to execute the method according to any one of claims 15 to 19 . A computer program for causing a computer to execute the method according to any one of claims 15 to 19 .

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