JP4638765B2 - Personal computer unauthorized use prevention system and personal computer - Google Patents

Description

  The present invention relates to a system for preventing unauthorized use of a personal computer, which prevents unauthorized use of a personal computer provided in a facility where entry is controlled, and allows restriction of use when the personal computer is restarted. Regarding personal computers.

Conventionally, as a technique for preventing unauthorized use of a personal computer by a third party who does not have the use authority, an information storage medium such as an IC card in which ID information for personal authentication is stored in advance when the personal computer is used There is already known a security technology that enables the use of a personal computer when the personal authentication is established by reading the ID information from the personal computer and performing personal authentication based on the read ID information. (For example, see Patent Document 1)
JP 2003-30155 A

In these security technologies, since authentication processing is performed to determine whether or not the user is an identity based on ID information stored in an information storage medium such as an IC card when a personal computer is used, these information storage media are forged. In such a case, there is a problem that a third party illegally uses the personal computer.
For example, a third party who does not have the authority to use a personal computer steals confidential data stored in the personal computer by stealing from a window or back door and illegally using the personal computer using a forged information storage medium. There is also a risk of fraudulent acts such as destroying data or altering stored data.
In other words, PCs are often in a usable state when identity authentication is approved, and today, where card counterfeiting is a problem, new technologies are required to improve the security of PCs. Yes.

In recent years, in order to perform security management, a third party other than the person who has the authority to enter the room cannot enter the room by performing personal authentication based on the ID information stored in the ID card when entering the room. It is also being systematized like this.
However, a person who has the authority to enter the room opens the door, and a third party impersonates the employee impersonating the employee, etc., and an employee who has the authority to use the PC steals the ID card and leaves the desk. There is a problem that there is a risk that the personal computer processing is performed.
Furthermore, like an internal crime, there is a risk that a trusted employee may steal an ID card and perform unauthorized personal computer processing when another employee leaves his / her seat.

  In other words, even if entry management is performed and personal authentication is performed using ID information stored in an information storage medium such as an IC card when a personal computer is used, these security technologies can be used in an unauthorized manner. There is a problem that there is a risk of illegal manipulation of data, theft or tampering due to the use of a personal computer or an illegal personal computer due to an internal crime.

  In the present invention, a personal computer installed in a facility where entry management is performed by personal authentication may be illegally used by a third party who does not have the authority to use the personal computer when the authorized personal computer user leaves his / her seat. Providing a system for preventing unauthorized use of personal computers and personal computers that prevent unauthorized use of personal computers by crime.

    An unauthorized use prevention system for a personal computer according to the present invention includes an information storage medium possessed by a person having authority to use a personal computer, a first device provided near the entrance of a facility where the personal computer is provided, and the personal computer. And an unauthorized use prevention system for a personal computer, wherein the information storage medium has a flag area for indicating that personal authentication has been received and stores ID information. And the first device is configured to read the ID information stored in the information storage medium and to authenticate the user in the authentication process based on the read ID information. And a means for transmitting a signal for writing a flag to the flag area of the information storage medium, wherein the second device is provided in the flag area of the storage means of the information storage medium. Means for reading lag information, means for transmitting processing end time information in the personal computer to the information storage medium, and means for reading end time information written in the storage means of the information storage medium. The personal computer is determined to determine whether or not a flag is written in the flag information read by the reading means of the second device, and the flag determination means determines that the flag is written. A start restriction releasing means for releasing the start restriction of the personal computer, an end time information writing means for writing end time information from the second device to the information storage medium at the end of processing of the personal computer, Time measuring means for measuring the current time; end time information reading means for reading the end time information written in the information storage medium from the second device; Storage means in which time limit information from the previous end time to restart of the personal computer is registered in advance, and when the personal computer is restarted, the elapsed time from the end time information to the current time is measured Elapsed time measuring means, determination means for determining whether the elapsed time measured by the elapsed time measuring means is within the time limit of the time limit information, and the determination means are determined to be within the time limit. And a means for canceling the start restriction when the personal computer is restarted.

  The personal computer of the present invention is connected to a second device capable of reading an information storage medium possessed by a person having authority to use the personal computer, which can be read by the first device provided near the entrance of the facility. A personal computer, wherein the personal computer determines that a flag is written in the flag information read by the second device, and the flag determination unit determines that the flag is written. Activation restriction releasing means for releasing activation restriction of the personal computer, and end time information writing means for writing end time information from the second device to the information storage medium at the end of processing of the personal computer. Time measuring means for measuring the current time, end time information reading means for reading the end time information written in the information storage medium from the second device, Storage means in which time limit information from the previous end time to the restart of the personal computer is registered in advance, and the elapsed time from the end time information to the current time when the personal computer is restarted A time measurement unit, a determination unit that determines whether the elapsed time measured by the elapsed time measurement unit is within the time limit of the time limit information, and the determination unit is determined to be within the time limit In this case, the personal computer is provided with means for canceling the start restriction when the personal computer is restarted.

  The personal computer unauthorized use prevention system according to the present invention performs personal authentication processing with ID information stored in an information storage medium when entering a facility equipped with a personal computer and restarts after the use of the personal computer is completed. If the preset time has passed since the last use end time, the restart is restricted so that the computer cannot be used. There is an effect that it is possible to prevent unauthorized use by a third party who does not have the authority to use, or unauthorized use of a personal computer by an internal crime.

  The personal computer of the present invention can prevent a legitimate personal computer user from leaving the seat and being illegally used by a third party who does not have the authority to use, or an illegal personal computer being used by an internal crime. There is.

Hereinafter, an unauthorized use prevention system for a personal computer and a personal computer according to an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram for explaining an outline of an unauthorized use prevention system for a personal computer according to an embodiment of the present invention, FIG. 2 is a plan view of a non-contact IC card, and FIG. 3 is a cross-sectional view taken along line AA in FIG. 4 is a plan view of an IC tag built in a non-contact IC card, FIG. 5 is a system block diagram of an unauthorized use prevention system for a personal computer according to an embodiment of the present invention, and FIG. 6 is an embodiment of the present invention. FIG. 7 and FIG. 8 are diagrams for explaining information stored in a non-contact IC card in the personal computer unauthorized use prevention system according to FIG. 7, and FIG. 7 and FIG. 8 are flowcharts for explaining the processing procedure of the personal computer unauthorized use prevention system according to the embodiment of the present invention. It is.

First, an outline of an unauthorized use prevention system for a personal computer according to an embodiment of the present invention will be described with reference to FIG.
The facility in the present invention includes, for example, a facility in which entry or entry of a room, a building, a floor in a building, a specific place, a specific area, a specific area, a specific area, etc. is managed. In the description of the form, a room equipped with a personal computer will be described as an example.

As shown in FIG. 1, a personal computer 1 is provided in a room 4 in which entry is managed.
A user 2 who is given authority to use the personal computer 1 from the company that owns the personal computer 1 is provided with a non-contact IC card 3 as an information storage medium from the company.
This non-contact IC card 3 may be an ID card that is provided to the employee by the company that owns the personal computer 1, and a third party other than an employee who does not have the non-contact IC card 3 as an ID card. Does not operate the personal computer 1 illegally.

Further, an entrance management device 6 as a first device is provided in the vicinity of the entrance 5a of the room 4, and the entrance / exit management device 6 controls the opening / closing and locking states of the automatic door 7 provided at the entrance 5a. Has been.
The entrance management device 6 is configured to be able to transmit information wirelessly to and from the non-contact IC card 3, read information stored in the non-contact IC card 3, and read information to the non-contact IC card 3. It is possible to write information.
Then, the entrance management device 6 sets the automatic door 7 in a locked state based on the result of the authentication process based on the ID information stored in the non-contact IC card 3 possessed by the user 2, or the door The entrance management is performed so that a third party cannot enter the room illegally by controlling whether or not the room is opened.

Further, the personal computer 1 is provided with a reader / writer 9 which is a second device, and wirelessly reads information stored in the non-contact IC card 3 and writes information to the non-contact IC card 3. It is configured to be able to do with.
Thereby, the information read from the non-contact IC card 3 by the reader / writer 9 can be sent to the personal computer 1, and the information from the personal computer 1 can be transmitted to the non-contact IC card 3 via the reader / writer 9. .

Furthermore, an exit management device 10 is provided in the vicinity of the outlet 5b of the room 4, and the open / close state of the automatic door 7 is controlled by the exit management device 10.
The exit management device 10 is configured to be able to transmit information wirelessly to and from the non-contact IC card 3, read information stored in the non-contact IC card 3, and send information to the non-contact IC card 3. It is possible to write the information.
In addition, there are a case where the entrance 4a and the exit 5b are provided separately in the room 4, and a case where the entrance 5a and the exit 5b are combined as one entrance, but FIG. 1 shows the case where one entrance is used. It is shown.
In addition, when the entrance / exit of the room 4 is made into one, the entrance management apparatus 6 and the exit management apparatus 10 are comprised integrally, and you may make it provide the function of these apparatuses collectively in one apparatus, A wall separating the outside and the inside of the room may be cut out.

Further, the non-contact IC card 3 which is an information storage medium has a configuration in which a non-contact IC tag 8 is built in the card bases 3a and 3b, for example, as shown in FIGS. .
The non-contact IC tag 8 is also referred to as, for example, a non-contact data carrier or RFID. As shown in FIG. 4, a transmission / reception means 88 formed of a coil pattern is formed on a base material 81 such as plastic, and the coil, capacitive element, Thus, a resonance circuit is formed so as to receive and transmit radio waves having a constant frequency.
As another method, power transmission and data transmission may be performed by electromagnetic induction of a carrier wave from a reader / writer.
Generally, a frequency band of 135 kHz (medium wave), 13.56 MHz, and 2.45 GHz (microwave) is used.

In the case of the illustrated example, the transmission / reception means 88 formed of a coil pattern forms a jumping circuit on the back surface of the substrate 81 by the conductive member 84 and is connected to the bumps on the back surface of the IC chip 82 by the coil connection terminals 88C.
The IC chip 82 includes a control unit 89 that is a CPU and a storage unit 90 that is a memory.

In the illustrated example, the capacitive element is built in the IC chip 82.
Such a non-contact IC tag 8 is formed by forming a coil pattern by photo etching or etching after resist printing on a metal foil such as an aluminum foil laminated on a resin base material, mounting an IC chip 82, and providing a protective coating. It can be formed by providing.
The size can also be set to about 30 mm × 30 mm or less.

As the resin base material 81 used for the non-contact IC tag 8, various materials such as PET, polypropylene, polyethylene, polystyrene, and nylon can be used, and paper may be used.
A thickness of 15 to 300 μm can be used, but 20 to 100 μm is more preferable from the viewpoint of strength, workability, cost, and the like.
Although copper foil, aluminum foil, or iron foil can be used as the metal foil, aluminum foil is preferable from the viewpoint of cost and workability, and the thickness is preferably about 6 to 50 μm.

  For reading and writing information recorded on these non-contact IC tags 8, a resonating call signal is transmitted from the reader / writer 9 to the non-contact IC tag 8, and contactless at a distance of several centimeters to several tens of centimeters. The response signal from the IC tag 8 can be read, and the information recorded in the memory that is the storage means of the IC chip 82 of the non-contact IC tag 8 can be read or the information can be written.

Next, the configuration of a personal computer unauthorized use prevention system and a personal computer according to an embodiment of the present invention will be described in detail based on the system block diagram shown in FIG.
FIG. 5 shows a system configuration relating to the non-contact IC card 3, the room entrance management device 6, the reader / writer 9, and the personal computer 1.
The entrance management device 6 provided in the vicinity of the entrance 5a includes a transmission / reception means 11, an authentication determination means 12, a door lock control means 13, an entrance flag writing means 14, a storage means 15, a control means 16, and the like. .
The transmission / reception means 11 transmits / receives information wirelessly to / from the transmission / reception means 88 of the non-contact IC card 3.
The authentication determination unit 12 has a function of performing personal authentication processing by comparing the ID information received from the non-contact IC card 3 with the ID information for verification stored in the storage unit 15 in advance. When the authentication process is performed by the authentication determination unit 12, the door lock is released by the door lock control unit 13 and the automatic door 7 is opened.

Further, the room entry flag writing means 14 permits the transmission / reception means 11 of the room entry management device 6 to authenticate the non-contact IC card 3 and to enter the room when the authentication determination means 12 receives the identity authentication. By transmitting flag information indicating that this has been done, the flag information is written into the flag area of the storage means 90 of the non-contact IC card 3.
By transmitting flag information from the entrance management device 6 to the non-contact IC card 3, the flag area of the storage unit 90 of the non-contact IC card 3 changes from “00” which is the state before writing to “01” which is the state after writing. To "".
Therefore, by determining whether the state stored in the flag area of the storage means 90 of the non-contact IC card 3 is “00” or “01”, the non-contact IC card 3 is possessed. It is possible to know whether the person who entered the room is the person who entered the room after receiving the identity authentication.

Next, the reader / writer 9 is provided with a transmission / reception means 17, a storage means 18, an interface (I / F) 19, a control means 20, and the like.
The transmission / reception means 17 transmits / receives information to / from the transmission / reception means 88 of the non-contact IC card 3 wirelessly.
The reader / writer 9 is connected to the interface (I / F) of the personal computer 1 via the interface (I / F) 19, and flag information and end time information read from the non-contact IC card 3 by the reader / writer 9. Is transmitted to the personal computer 1 and the end time information received by the reader / writer 9 from the personal computer 1 can be transmitted to the non-contact IC card 3.

  Next, the personal computer 1 includes a display unit 21, a flag determination unit 22, a start restriction release unit 23, an end time information writing unit 24, an interface (I / F) 25, a time measuring unit 26, an input unit 27, and an end time information. A reading unit 28, a storage unit 29, an elapsed time measurement unit 30, an elapsed time determination unit 31, a start restriction release unit 32, a control unit 33, and the like are provided.

First, the flag determination means 22 reads the flag information stored in the flag area of the storage means 90 of the non-contact IC card 3 by the reader / writer 9 and determines whether or not the flag is written in the flag area. It has a function to perform.
Next, the activation restriction releasing unit 23 has a function of releasing the activation restriction so that the personal computer 1 can be activated when the flag determining unit 22 determines that the flag is written in the flag area. ing.
The personal computer 1 is restricted to a state in which it cannot be activated until the activation restriction is canceled by the activation restriction releasing means 23.

  The end time information writing means 24 also stores the current time information measured by the time measuring means 26 at the end of the processing of the personal computer 1 in the storage means 90 that has been transmitted to the non-contact IC card 3 by the reader / writer 9. Is written as end time information.

  The end time information reading means 28 has a function of reading the end time information of the personal computer 1 stored in the storage means 90 of the non-contact IC card 3 by the reader / writer 9 when the personal computer 1 is restarted. Yes.

In the storage means 29 of the personal computer 1, time limit information from the previous end time of the personal computer 1 to the restart is registered in advance.
This time limit information is used when the person who has entered the room after authenticating his / her identity does not leave the room and uses the same personal computer 1 during the room entry. By setting a certain time limit for the elapsed time from the time of use, a third party can illegally use a computer when a legitimate computer user leaves the desk for a long time. Thus, it is possible to prevent various operations from being performed.

This is because when a legitimate PC user leaves the PC 1 with the contactless IC card 3 in the seat, a third party activates the PC 1 using the contactless IC card 3. In order to prevent unauthorized processing, a time limit is provided.
Therefore, it is not appropriate to set these time limits for a long time, but considering the size of the room in which the personal computer 1 is installed, the necessity of leaving the seat according to the work content, the required time away from the desk, etc. The time limit may be set arbitrarily.

Next, the elapsed time measuring unit 30 calculates the current time information from the end time of the personal computer 1 from the end time information of the personal computer 1 read by the end time information reading unit 28 and the current time information measured by the time measuring unit 26. It has a function of calculating how much time has elapsed until the personal computer 1 is restarted.
The elapsed time determination unit 31 compares the elapsed time calculated by the elapsed time measurement unit 30 with the time limit registered in advance in the storage unit 29, and determines whether or not the elapsed time is within the time limit. Has a function of performing the determination process.

Further, the activation restriction releasing unit 32 releases the activation restriction so that the personal computer 1 can be restarted when the elapsed time determining unit 31 determines that the elapsed time is within the time limit. 1 has a function of restarting 1 so that processing can be performed.
Accordingly, when the activation limit canceling means 32 determines that the elapsed time exceeds the time limit in the determination by the elapsed time determining means 31, the activation restriction of the personal computer 1 is not canceled, so that the personal computer 1 is restarted. The third party personal computer 1 can be prevented from being illegally used by preventing the activation and processing.

FIG. 6 shows changes in flag area information and time information stored in the storage means 90 of the non-contact IC card 3.
First, when entering the flag area from the entrance of the room 1, if the person authentication is received by the authentication determination means 12 by the entrance management apparatus 6, the entrance management apparatus 6 applies the contactless IC card 3 to the flag area. Flag information indicating that entry is permitted upon receiving personal authentication is transmitted, “01” as flag information is written in the flag area of the storage means 90 of the non-contact IC card 3, and “01” is written in the flag area. Is stored.
The information “01” stored in the flag area indicates that when the user leaves the room 4, the flag is erased by an erase signal from the reader / writer 10 provided at the exit of the room 4. Once done, it changes from “01” to “00”.

Further, the time information stored in the storage means 90 of the non-contact IC card 3 is “00000000000000” at the stage before the personal computer 1 is started on that day. If the end time when the personal computer 1 is once turned off (shutdown) at the time of leaving or the like is 18:05:15 on August 25, 2004, end time information of “200408825180515” is registered.
Thereafter, if the user returns to the seat and restarts the personal computer 1 for example, 4 minutes and 15 seconds after the shutdown, the time information “200408825180930” is registered.

If the end time when the personal computer 1 is turned off (shutdown) at the end of the day is 18: 5: 15 on August 25, 2004, the time information "200408825180515" is registered.
Further, when the user of the personal computer leaves the room, the time information stored in the storage means 90 of the non-contact IC card 3 is erased by a signal from the reader / writer provided at the exit of the room, “00000000000000”.
As described above, when the user leaves the room, all the flag area information and time information stored in the storage means 90 of the non-contact IC card 3 are erased, and the user can connect the personal computer after the next day. When used, the same processing is performed.

Next, the processing procedure of the embodiment of the present invention will be described based on the flowchart shown in FIG.
First, when a user who intends to use the personal computer 1 provided in the room 4 enters the room 4 through the entrance of the room 4, the non-contact IC card 3 is brought closer to the entrance management apparatus 6, thereby entering the room management apparatus. 6 reads the ID information stored in the storage means 90 of the non-contact IC card 3. (Step S1)
Then, the authentication determination means 12 of the room entry management device 6 performs the personal authentication determination for the read ID information. (Step S2)

When the personal authentication is recognized in this personal authentication determination, a signal is transmitted from the transmitting / receiving means 11 to the non-contact IC card 3 by the entrance flag writing means 14 of the entrance management device 6, and the non-contact IC card 3 A flag is written in the entry flag area of the storage means. (Step S3)
At substantially the same time, the lock of the automatic door 7 is released by the door lock control means 13, and the automatic door 7 opens to enter the room. (Step S4)

  In addition, if the identity authentication is not permitted in the identity authentication determination in the step S2, no signal is transmitted from the transmission / reception means 11 to the non-contact IC card 3 by the entry flag writing means 14 of the entry management device 6. Moreover, it complete | finishes without entering into a room in the state which the automatic door 7 closed.

Next, the person who enters the room from the entrance brings the non-contact IC card 3 close to the reader / writer 9 provided in the personal computer 1 and reads the flag information in the flag area of the non-contact IC card 3. (Step S5)
Then, it is determined whether or not a flag is written in the flag area of the non-contact IC card 3. (Step S6)
Here, if it is determined that the flag is written in the flag area, the activation lock of the personal computer 1 is released by the activation restriction releasing means 32, and the personal computer 1 becomes usable. (Step S7)

If it is determined that the flag is not written in the flag area, the activation lock of the personal computer 1 is not released and the personal computer 1 cannot be used and the person can use the personal computer 1 Exit without being able to.
This prevents unauthorized use of a personal computer by a person who has not been authenticated.

In addition, when a user who can use the personal computer 1 leaves his / her seat for his / her purpose, for example, once the processing of the personal computer 1 is finished and the power is turned off, the personal computer 1 can contact the IC card. 3, the end time information is transmitted via the reader / writer 9, and the end time information is stored in the storage means of the non-contact IC card 3. (Step S8)
Then, after the user returns to the seat, when the personal computer 1 is turned on and restarted, the personal computer 1 reads the end time information from the non-contact IC card 3 via the reader / writer 9. (Step S9)
Further, the elapsed time between the read end time information and the current time information measured by the time measuring means of the personal computer 1 is calculated. (Step S10)

Next, it is determined whether the elapsed time is within the time limit by comparing the calculated elapsed time with the time limit registered in advance in the storage unit 29. (Step S11)
If it is determined in this determination that the elapsed time is within the time limit, the start restriction of the personal computer 1 is released and the computer 1 can be restarted. (Step S12)
Further, when the process of the restarted personal computer 1 is finished and the power is turned off, the end time information is registered in the storage means 29 each time. (Step S13)

  Then, the processing of the personal computer 1 on that day is finished, the power is turned off, and when leaving the room 4, the storage means of the non-contact IC card 3 is received by a signal from the reader / writer 10 provided at the exit of the room 4. The time information stored in 90 is erased, and the flag written in the flag area is erased. (Step S14)

  As described above, according to the present invention, even when a user of a personal computer leaves a seat and another person tries to cheat using the personal computer, the computer automatically Since it is restricted so that it cannot be started, unauthorized use of the personal computer can be prevented.

It is a figure explaining the outline | summary regarding the unauthorized use prevention system and personal computer of the personal computer which concern on embodiment of this invention. It is a top view of a non-contact IC card. It is the sectional view on the AA line of FIG. It is a top view of the IC tag built in the non-contact IC card. 1 is a system block diagram of a personal computer unauthorized use prevention system according to an embodiment of the present invention. It is a figure explaining the information memorize | stored in the non-contact IC card in the unauthorized use prevention system of the personal computer which concerns on embodiment of this invention. It is a flowchart explaining the process sequence of the unauthorized use prevention system of the personal computer which concerns on embodiment of this invention. It is a flowchart explaining the process sequence of the unauthorized use prevention system of the personal computer which concerns on embodiment of this invention.

Explanation of symbols

1 PC
2 users
3 Non-contact IC card
4 rooms
5a entrance
5b Exit
6 Entrance management device
7 Automatic door
9 Reader / Writer
10 Exit management device
11, 17, 88 Transmission / reception means
12 Authentication judgment means
13 Door lock control means
14 Entry flag writing means
15, 18, 29, 90 Storage means
16, 20, 33, 89 Control means
19, 25 interface (I / F)
21 Display means
22 Flag determination means
23 Start restriction release means
24 End time information writing means
26 Timekeeping means
27 Input means
28 End time information reading means
30 Measuring means for elapsed time
31 Elapsed time judging means
32 Start restriction release means

Claims (2)

An information storage medium possessed by a person having authority to use a personal computer, a first device provided near the entrance of a facility provided with the personal computer, a second device provided in the personal computer, An unauthorized use prevention system for personal computers consisting of
The information storage medium has a flag area for indicating that personal authentication has been received, and storage means for storing ID information,
The first device is configured to read the ID information stored in the information storage medium and the flag area of the information storage medium when personal authentication is received by the authentication process based on the read ID information. Means for transmitting a signal for writing a flag to
The second device includes means for reading flag information in a flag area of a storage means of the information storage medium, means for transmitting processing end time information in the personal computer to the information storage medium, and the information storage medium Means for reading the end time information written in the storage means,
The personal computer has flag determination means for determining whether or not a flag is written in the flag information read by the reading means of the second device, and the flag determination means determines that the flag is written A start restriction releasing means for releasing the start restriction of the personal computer, an end time information writing means for writing end time information from the second device to the information storage medium at the end of the processing of the personal computer, A time measuring means for measuring the time, an end time information reading means for reading the end time information written in the information storage medium from the second device, and a limit from the previous end time to restart of the personal computer Storage means in which time information is registered in advance and a time for measuring the elapsed time from the end time information to the current time when the personal computer is restarted. A time measurement unit, a determination unit that determines whether the elapsed time measured by the elapsed time measurement unit is within the time limit of the time limit information, and the determination unit is determined to be within the time limit And a means for canceling the start restriction when the personal computer is restarted. A personal computer connected to a second device capable of reading an information storage medium possessed by a person having authority to use the personal computer, which can be read by the first device provided near the entrance of the facility,
The personal computer determines whether the flag is written in the flag information read by the second device, and when the flag determination unit determines that the flag is written, An activation restriction releasing means for releasing activation restrictions on the personal computer, an end time information writing means for writing end time information from the second device to the information storage medium at the end of processing of the personal computer, and a current time Time measuring means for measuring, end time information reading means for reading the end time information written in the information storage medium from the second device, and time limit information from the previous end time to restart of the personal computer. Pre-registered storage means and elapsed time measurement for measuring elapsed time from the end time information to the current time when restarting the personal computer A determination means for determining whether the elapsed time measured by the elapsed time measurement means is within the time limit of the time limit information, and when the determination means determines that the elapsed time is within the time limit And a means for canceling the start restriction when the personal computer is restarted.

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