Device authentication management system Number:7,143,436 from the United States Patent and Trademark Office (PTO) owispatent

Title: Device authentication management system

Abstract: In a device authentication management system in which a device acquires a secret information from an authentication management unit and carries out an authentication in order to carry out communications with another device by using the secret information, the authentication management unit generates the secret information that contains a first authentication information for carrying out communications between the authentication management unit and the device, and a second authentication information for carrying out communications between the device and the another device; carries out the authentication in order to carry out communications with the device, by using the first authentication information; and transmits the second authentication information according to the authentication.

Patent Number: 7,143,436 Issued on 11/28/2006 to Yamaguchi,   et al.

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Inventors:	Yamaguchi; Kensaku (Kanagawa, JP), Nakakita; Hideaki (Kanagawa, JP), Hashimoto; Mikio (Kanagawa, JP)
Assignee:	Kabushiki Kaisha Toshiba (Tokyo, JP)
Appl. No.:	10/253,644
Filed:	September 25, 2002

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Foreign Application Priority Data

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Sep 25, 2001 [JP]			2001-292581

Current U.S. Class:	726/6 ; 380/277; 713/168; 726/15
Current International Class:	G06F 15/173 (20060101); G06F 15/16 (20060101); H04L 9/00 (20060101); H04N 1/44 (20060101)

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References Cited [Referenced By]

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U.S. Patent Documents

	6185308		February 2001		Ando et al.
	6185682		February 2001		Tang
	6289451		September 2001		Dice

Foreign Patent Documents

	09-083509		Mar., 1997		JP
	9-252294		Sep., 1997		JP
	2000-196616		Jul., 2000		JP
	2000-253459		Sep., 2000		JP
	2001-111543		Apr., 2001		JP
	WO 99/27654		Jun., 1999		WO

Primary Examiner: Barron; Gilberto
Assistant Examiner: Lashley; Laurel
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier & Neustadt, P.C.

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Claims

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What is claimed is:

1. A device authentication management system, comprising: an authentication management unit configured to manage a prescribed secret information; and a device configured to acquire the prescribed secret information from the authentication management unit and carry out an authentication in order to carry out communications with another device by using the prescribed secret information; wherein the authentication management unit has: a generation unit configured to generate the prescribed secret information that contains a first authentication information for carrying out communications between the authentication management unit and the device, and a second authentication information for carrying out communications between the device and the another device; a first authentication unit configured to carry out the authentication in order to carry out communications with the device, by using the first authentication information generated by the generation unit; and a first communication unit configured to transmit the second authentication information according to the authentication by the first authentication unit; and the device has: a second authentication unit configured to carry out the authentication in order to carry out communications with the first authentication unit by using the first authentication information acquired in advance from the authentication management unit; and a second communication unit configured to receive the second authentication information from the first communication unit according to the authentication by the second authentication unit.

2. The device authentication management system of claim 1, wherein the second authentication unit has a function for carrying out the authentication in order to carry out communications with the another device by using the second authentication information received by the second communication unit, and the second communication unit has a function for carrying out communications with the another device according to the authentication by the second authentication unit.

3. The device authentication management system of claim 2, wherein the generation unit generates the second authentication information which has an identifier for identifying the second authentication information and a valid period information for indicating a valid period during which the second authentication information can be used.

4. The device authentication management system of claim 3, wherein the device also has: a selection unit configured to acquire the identifiers contained in a plurality of the second authentication informations available at the another device, extract those identifiers that are common to acquired identifiers and the identifiers contained in a plurality of the second authentication informations available at the device, and select one of the second authentication informations corresponding to the valid period information among the second authentication informations corresponding to extracted identifiers according to the valid period information corresponding to the extracted identifiers; and the second authentication unit has a function for carrying out the authentication in order to carry out communications with the another device according to the second authentication information selected by the selection unit.

5. The device authentication management system of claim 2, wherein the device also has: a time attaching unit configured to attach a time information for indicating a time at which the second communication unit acquired the second authentication information from the authentication management unit, to the second authentication information; and a selection unit configured to acquire a plurality of the second authentication informations with the time information attached thereto by the time attaching unit, and select one of the second authentication information corresponding to the time information among the plurality of the second authentication informations with the time information attached thereto according to the time information; and the second authentication unit has a function for carrying out the authentication with the another device according to the second authentication information selected by the selection unit.

6. The device authentication management system of claim 2, wherein the generation unit generates the second authentication information at a prescribed period, and the device also has: a selection unit configured to acquire a plurality of the second authentication informations generated at the prescribed periods by the generation unit, and delete one of the plurality of the second authentication informations acquired when a number of the plurality of the second authentication informations exceeds a prescribed number.

7. The device authentication management system of claim 1, wherein the generation unit generates the second authentication information which has an identifier for identifying the second authentication information and a valid period information for indicating a valid period during which the second authentication information can be used.

8. The device authentication management system of claim 7, wherein the device also has: a selection unit configured to acquire the identifiers contained in a plurality of the second authentication informations available at the another device, extract those identifiers that are common to acquired identifiers and the identifiers contained in a plurality of the second authentication informations available at the device, and select one of the second authentication informations corresponding to the valid period information among the second authentication informations corresponding to extracted identifiers according to the valid period information corresponding to the extracted identifiers; and the second authentication unit has a function for carrying out the authentication in order to carry out communications with the another device according to the second authentication information selected by the selection unit.

9. The device authentication management system of claim 7 wherein the device also has: a time attaching unit configured to attach a time information for indicating a time at which the second communication unit acquired the second authentication information from the authentication management unit, to the second authentication information; and a selection unit configured to acquire a plurality of the second authentication informations with the time information attached thereto by the time attaching unit, and select one of the second authentication information corresponding to the time information among the plurality of the second authentication informations with the time information attached thereto according to the time information; and the second authentication unit has a function for carrying out the authentication with the another device according to the second authentication information selected by the selection unit.

10. An authentication management device for use in a device authentication management system in which a device acquires a prescribed secret information from the authentication management device and carries out an authentication in order to carry out communications with another device by using the prescribed secret information, the authentication management device comprising: a generation unit configured to generate the prescribed secret information that contains a first authentication information for carrying out communications between the authentication management device and the device, and a second authentication information for carrying out communications between the device and the another device; an authentication unit configured to carry out the authentication in order to carry out communications with the device, by using the first authentication information generated by the generation unit; and a communication unit configured to transmit the second authentication information according to the authentication by the authentication unit.

11. A device for use in a device authentication management system in which the device acquires a prescribed secret information from an authentication management device and carries out an authentication in order to carry out communications with another device by using the prescribed secret information, the device comprising: an authentication unit configured to carry out the authentication in order to carry out communications with the authentication management device by using the first authentication information acquired in advance from the authentication management device; and a communication unit configured to receive the second authentication information from the authentication management device according to the authentication by the authentication unit.

12. A device authentication management method in which a device acquires a prescribed secret information from an authentication management unit and carries out an authentication in order to carry out communications with another device by using the prescribed secret information, the device authentication management method comprising: (a) generating the prescribed secret information that contains a first authentication information for carrying out communications between the authentication management unit and the device, and a second authentication information for carrying out communications between the device and the another device, at the authentication management unit; (b) carrying out the authentication in order to carry out communications with the device, by using the first authentication information generated by the step (b), at the authentication management unit; (c) transmitting the second authentication information according to the authentication by the step (b); (d) carrying out the authentication in order to carry out communications with the authentication management unit by using the first authentication information acquired in advance from the authentication management unit, at the device; and (e) receiving the second authentication information from the authentication management unit according to the authentication by the step (d), at the device.

13. The device authentication management method of claim 12, further comprising: (f) carrying out the authentication in order to carry out communications with the another device by using the second authentication information received by the step (e), at the device; and (g) carrying out communications with the another device according to the authentication by the step (f), at the device.

14. The device authentication management method of claim 13, wherein the step (a) generates the second authentication information which has an identifier for identifying the second authentication information and a valid period information for indicating a valid period during which the second authentication information can be used.

15. The device authentication management method of claim 14, further comprising: (h) acquiring the identifiers contained in a plurality of the second authentication informations available at the another device, extracting those identifiers that are common to acquired identifiers and the identifiers contained in a plurality of the second authentication informations available at the device, and selecting one of the second authentication informations corresponding to the valid period information among the second authentication informations corresponding to extracted identifiers according to the valid period information corresponding to the extracted identifiers, at the device; wherein the step (d) carries out the authentication in order to carry out communications with the another device according to the second authentication information selected by the step (k).

16. The device authentication management method of claim 13, further comprising: (i) attaching a time information for indicating a time at which the step (e) acquired the second authentication information from the authentication management unit, to the second authentication information, at the device; and (j) acquiring a plurality of the second authentication informations with the time information attached thereto by the step (i), and selecting one of the second authentication information corresponding to the time information among the plurality of the second authentication informations with the time information attached thereto according to the time information, at the device; and wherein the step (d) carries out the authentication with the another device according to the second authentication information selected by the step (j).

17. The device authentication management method of claim 13, wherein the step (a) generates the second authentication information at a prescribed period, and the device authentication management method further comprises: (k) acquiring a plurality of the second authentication informations generated at the prescribed periods by the step (a), and deleting one of the plurality of the second authentication informations acquired when a number of the plurality of the second authentication informations exceeds a prescribed number, at the device.

18. The device authentication management method of claim 12, wherein the step (a) generates the second authentication information which has an identifier for identifying the second authentication information and a valid period information for indicating a valid period during which the second authentication information can be used.

19. The device authentication management method of claim 18, further comprising: (l) attaching a time information for indicating a time at which the step (e) acquired the second authentication information from the authentication management unit, to the second authentication information, at the device; and (m) acquiring a plurality of the second authentication informations with the time information attached thereto by the step (l), and selecting one of the second authentication information corresponding to the time information among the plurality of the second authentication informations with the time information attached thereto according to the time information, at the device; and wherein the step (d) carries out the authentication with the another device according to the second authentication information selected by the step (m).

20. The device authentication management method of claim 18, wherein the step (a) generates the second authentication information at a prescribed period, and the device authentication management method further comprises: (n) acquiring a plurality of the second authentication informations generated at the prescribed periods by the step (a), and deleting one of the plurality of the second authentication informations acquired when a number of the plurality of the second authentication informations exceeds a prescribed number, at the device.

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Description

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BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device authentication management system for carrying out authentication such that a device that acquired a prescribed secret information from an authentication management unit that manages the secret information can carry out communications with another device by using the acquired secret information.

2. Description of the Related Art

In recent years, in conjunction with the advance of the LAN (Local Area Network) technique, the networking in the office environment has been developed mainly in forms of connections among PCs (Personal Computers). While such wired LANs are spreading, the use of the wireless LAN in which a part of the wired LAN is replaced by radio is also in progress. For example, according to this use of the wireless LAN, a radio base station is connected to the wired LAN and a plurality of portable PCs are connected to this base station by radio.

Then, the portable PC can make the communication connection with a PC connected to the wired LAN by Ethernet by radio, and edit a file of that PC with respect to which the communication connection is made. In this way, the portable PC can effectively make the radio access to the wired LAN.

Also, the portions between the base station and the portable PC are effectively forming a wireless LAN. The advantages of such a wireless LAN are that there is no need to lay cables because radio waves or infrared rays are used as transmission paths, and that a new construction or a layout change of the network is easy.

The introduction of such a wireless LAN is becoming popular due to the standardization of IEEE 802.11. In IEEE 802.11, the 2.4 GHz band wireless LAN specification was completed in 1997, and the 5 GHz band wireless LAN specification was completed in 1999. The transmission rate of the 2.4 GHz band wireless LAN specification is either 1 to 2 Mbps or 11 Mbps, and the specification with the transmission rate over 20 Mbps is currently under the discussion. Recently, products compatible with this 2.4 GHz band specification have been released by many companies so that the base station and the radio PC card are now priced in an affordable range of general users.

On the other hand, the 5 GHz band wireless LAN specification can realize the transmission rate of 20 to 30 Mbps. Also, unlike the 2.4 GHz band, 5 GHz band is currently almost unused frequency band in which faster transmission rates can be expected easily, so that it has a prospect of becoming the next generation wireless LAN specification. With the appearance of some venture company that plans to sell one chip with 5 GHz band communication function at $35 in 2001, communications in the 5 GHz band are now becoming familiar.

In addition, there is a trend to install the communication scheme based on the Bluetooth on all kinds of devices in a variety of fields including those of portable telephones, home electronics and PCs. This communication scheme based on the Bluetooth is also a 2.4 GHz band radio system, and the radio devices using the communication scheme based on the Bluetooth are expected to spread worldwide due to the facts that a chip adopting the communication scheme based on the Bluetooth requires a low cost of about $5 for one chip, the communication scheme based on the Bluetooth are accepted by approximately 2000 companies in a variety of fields, and there has been the standardization activity for the radio device using the communication scheme based on the Bluetooth that has been made in direct connection with the product developments.

From the circumstances described above, as radio devices are spread, the range of application of these techniques is expected to cover not just the office environment but also the general homes as well. In particular, the fact that there is no need to lay cables in the home is even greater advantage than the case of the office environment.

However, despite of the fact that the operation by radio is easy, the feature of the connection among the radio devices that it does not use an explicit connection such as that used in the case of the cable connection or the like tends to give rise to the problem of security and privacy. There is a possibility for having the radio device controlled from outside the home without consent, a possibility for having the personal information stolen from the radio device, or a possibility for data in the radio device to get destroyed.

Also, the internet connection is now shifting frog a part time basis to a full time basis, but when it becomes popular to make the full time connection through a radio network interface as a result, there is also a possibility for allowing a third person to intrude into the PC via the radio network interface by evading the firewall.

Also, the general home users are likely to experience some vague anxiety because of the circumstances in which the home users can learn some knowledge about the presence of threats related to the security such as eavesdropping and pretending, through news related to the computer virus from the PC industry or TV programs.

Under the business environment, it is relatively easy to take measures against these threats by hiring a specialist, and it is possible to implement the IPSEC or firewall and continually updating such software. However, under the home environment, it is expected to be rather difficult for many users to take such measures in general. For this reason, in the case of using the radio device at the home, there is a need for the sufficient security management in order to prevent the eavesdropping from the external or the like.

For this security management at the home, first an authentication management unit for comprehensively managing the security of each device is installed. Then, in order for the authentication management unit to manage the security of each device, each device for which the security management is desired makes a registration to the authentication management unit. Each device that made the registration to the authentication management unit as the security management is desired forms a radio network with the authentication management unit, and placed under the security management of the authentication management unit only during a prescribed valid period such that the eavesdropping from a third party device can be prevented.

Here, the valid period is a period for which the device can use the authentication information given from the authentication management unit, and there is a need for the device to carry out the updating of the valid period with respect to the authentication management unit regularly in order to update the valid period of the authentication information. The reasons for setting up the valid period for the authentication information in this way include that there is a need to prevent the device from being connected to the home radio network indefinitely, and that it becomes possible to reduce the danger of having the device connected to the home radio network unexpectedly even when this device is handed over to someone else or discarded because the valid period of the security management expires at some point.

More specifically, as shown in FIG. 25, an authentication management unit A carries out the security management for a device 10b and a device 10c, and an authentication management unit B carries out the security management of a device 10d and a device 10e. On the other hand, the authentication management unit A does not carry out the security management of a device 10a outside of the home and a device 10d of a neighboring home, and the authentication management unit B does not carry out the security management of a device 10f outside of the home. The device 10b and the device 10c of the A's home can carry out communications under the security management of the authentication management unit A by carrying out communications by using the authentication information given from the authentication management unit A. Also, the authentication management unit A (or B) can carry out the security management of specific devices 10b and 10c (or 10d and 10e) within a range of a radio network (indicated by a dashed line in FIG. 25) formed by the authentication management A (or B).

However, the end time of the valid period for which the security management can be carried out is managed by each device existing in a range for which the radio network is formed, but when a plurality of devices exist in a range of the radio network, they may not have the same end time. The reasons why the end times of the valid periods are not the same among the devices in general are that there can be cases where one device among the two devices attempts to update the new valid period earlier than the other device, and that there can be cases where times indicated by the timers provided in the devices may not be exactly the same.

Also, in the case where each device judges the valid period according to the time indicated by the timer provided in the own device, even if the time indicated by the timer is accurate at one point, it is inevitable for the timer to become fast or slow in future due to the structures of the CPU or the like provided inside the own device. For this reason, even if the start times of the valid periods of the secret keys are the same among the devices, there can be cases where the valid periods of the secret keys of the devices do not end at the same time in future.

Moreover, each device used at the home may not necessarily have its power turned on all the times, so that when the power of each device is not turned on, the update of the authentication information cannot be made until the power is turned on next time. In this case, the device which could not have updated the authentication information will have a delay until the power is turned on and the update of the authentication information is made, so that this device may have the authentication information different from the other devices during that period of time.

Consequently, even if the device has the secret key that is common to those of the other devices at a current timing, there can be cases where the secret key becomes not common to those of the other devices in future as described above, and there is a possibility for that device to become impossible to carry out communications with the other devices by using the secret key provided in the own device.

When there is a difference in the end times of the valid periods of the devices as described above, each device may encounter the problems such as the communications with the other devices cannot be started, or the communications carried out with the other device are interrupted in a middle. For example, the devices using the radio scheme based on the Bluetooth are carrying out point-to-point (device-to-device) communications so that the communications will be interrupted if the timings for updating the authentication information among these devices are not aligned. Also, for the devices using the broadcast type radio scheme such as IEEE 802.11 wireless LAN, it is difficult to identify the number of devices participating in the communications, but unless all these devices have the same authentication information, there is a possibility for having the communications interrupted partially.

BRIEF SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a device authentication management system capable of preventing a situation in which it becomes impossible for each device to start the communications with the other devices when there is a difference in the end times of the valid periods of the secret keys provided in the devices.

According to one aspect of the present invention there is provided a device authentication management system, comprising: an authentication management unit configured to manage a prescribed secret information; and a device configured to acquire the prescribed secret information from the authentication management unit and carry out an authentication in order to carry out communications with another device by using the prescribed secret information; wherein the authentication management unit has: a generation unit configured to generate the prescribed secret information that contains a first authentication information for carrying out communications between the authentication management unit and the device, and a second authentication information for carrying out communications between the device and the another device; a first authentication unit configured to carry out the authentication in order to carry out communications with the device, by using the first authentication information generated by the generation unit; and a first communication unit configured to transmit the second authentication information according to the authentication by the first authentication unit; and the device has: a second authentication unit configured to carry out the authentication in order to carry out communications with the first authentication unit by using the first authentication information acquired in advance from the authentication management unit; and a second communication unit configured to receive the second authentication information from the first communication unit according to the authentication by the second authentication unit.

According to another aspect of the present invention there is provided an authentication management device for use in a device authentication management system in which a device acquires a prescribed secret information from the authentication management device and carries out an authentication in order to carry out communications with another device by using the prescribed secret information, the authentication management device comprising: a generation unit configured to generate the prescribed secret information that contains a first authentication information for carrying out communications between the authentication management device and the device, and a second authentication information for carrying out communications between the device and the another device; an authentication unit configured to carry out the authentication in order to carry out communications with the device, by using the first authentication information generated by the generation unit; and a communication unit configured to transmit the second authentication information according to the authentication by the authentication unit.

According to another aspect of the present invention there is provided a device for use in a device authentication management system in which the device acquires a prescribed secret information from an authentication management device and carries out an authentication in order to carry out communications with another device by using the prescribed secret information, the device comprising: an authentication unit configured to carry out the authentication in order to carry out communications with the authentication management device by using the first authentication information acquired in advance from the authentication management device; and a communication unit configured to receive the second authentication information from the authentication management device according to the authentication by the authentication unit.

According to another aspect of the present invention there is provided a device authentication management method in which a device acquires a prescribed secret information from an authentication management unit and carries out an authentication in order to carry out communications with another device by using the prescribed secret information, the device authentication management method comprising: (a) generating the prescribed secret information that contains a first authentication information for carrying out communications between the authentication management unit and the device, and a second authentication information for carrying out communications between the device and the another device, at the authentication management unit; (b) carrying out the authentication in order to carry out communications with the device, by using the first authentication information generated by the step (b), at the authentication management unit; (c) transmitting the second authentication information according to the authentication by the step (b); (d) carrying out the authentication in order to carry out communications with the authentication management unit by using the first authentication information acquired in advance from the authentication management unit, at the device; and (e) receiving the second authentication information from the authentication management unit according to the authentication by the step (d), at the device.

Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing an exemplary configuration of a device authentication management system according to the first embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of the device authentication management system according to the first embodiment of the present invention.

FIG. 3 is a diagram showing an OSI structure of an authentication unit in the first embodiment of the present invention.

FIG. 4 is a diagram showing a first part of a procedure for a device to acquire a common key from an authentication management unit in the first embodiment of the present invention.

FIG. 5 is a diagram showing a second part of a procedure for a device to acquire a common key from an authentication management unit in the first embodiment of the present invention.

FIG. 6 is a diagram showing a third part of a procedure for a device to acquire a common key from an authentication management unit in the first embodiment of the present invention.

FIG. 7 is a diagram showing a case where an authentication management unit manages a plurality of devices using different communication schemes in the first embodiment of the present invention.

FIG. 8 is a diagram showing a state transition of a device in the first embodiment of the present invention.

FIG. 9 is a sequence chart showing a procedure for a device to acquire a common key from an authentication management unit in the first embodiment of the present invention.

FIG. 10 is a sequence chart showing a procedure for an authentication management unit to delete a registration information of a device in the first embodiment of the present invention.

FIG. 11 is a diagram showing a procedure by which a device carries out an authentication with another device by using one of a plurality of common keys in the first embodiment of the present invention.

FIG. 12 is a sequence chart showing a procedure by which a device carries out the authentication with another device by using a common key in the first embodiment of the present invention.

FIG. 13 is a diagram showing a case where a device carries out the authentication with a plurality of other devices in the first embodiment of the present invention.

FIG. 14 is a diagram showing a case where a plurality of devices carry out the authentication by using one of a plurality of common keys in the first embodiment of the present invention.

FIG. 15 is a diagram showing a procedure by which a device carries out the authentication with another device when a common key is updated from an authentication management unit in the first embodiment of the present invention.

FIG. 16 is a flow chart showing a procedure by which a device carries our communications with another device in the first embodiment of the present invention.

FIG. 17 is a flow chart showing a procedure by which a device carries out communications with another device when a common key is updated from an authentication management unit in the first embodiment of the present invention.

FIG. 18 is a diagram showing a procedure by which a device updates a common key from an authentication management unit in the first embodiment of the present invention.

FIG. 19 is a block diagram showing an internal configuration of the device authentication management system according to the second embodiment of the present invention.

FIG. 20 is a diagram showing a procedure by which a device acquires common keys at prescribed timings from an authentication management unit in the second embodiment of the present invention.

FIG. 21 is a diagram showing one procedure by which a plurality of devices acquire common keys at prescribed timings from an authentication management unit in the second embodiment of the present invention.

FIG. 22 is a diagram showing another procedure by which a plurality of devices acquire common keys at prescribed timings from an authentication management unit in the second embodiment of the present invention.

FIG. 23 is a diagram showing a procedure by which a plurality of devices using different communication schemes acquire common keys at prescribed timings from an authentication management unit in the second embodiment of the present invention.

FIG. 24 is a diagram showing a procedure by which a plurality of devices using different communication schemes acquire common keys at different updating periods from an authentication management unit in the second embodiment of the present invention.

FIG. 25 is a diagram showing a conventional home radio network.

DETAILED DESCRIPTION OF THE INVENTION

[First Embodiment]

Referring now to FIG. 1 to FIG. 18, the first embodiment of a device authentication management system according to the present invention will be described in detail.

(Configuration of the Device Authentication Management System)

FIG. 2 shows an internal configuration of a device authentication management system according to this embodiment. As shown in FIG. 2, in this device authentication management system, a device 10a that has acquired a secret information from an authentication management unit 20 for managing a prescribed secret information carries out the authentication in order to carry out communications with another device 10b by using the acquired secret information.

Here, the authentication management unit 20 has a secret information generation unit 22 for generating the secret information comprising a first authentication information to be used for carrying out communications between the authentication management unit 20 and the device 10 and a second secret information to be used for carrying out communications between the device 10 and the other device 10, an authentication unit 26 for carrying out the authentication in order to carry out communications with the device 10 by using the first authentication information generated by the secret information generation unit 22, and a communication unit 25 for transmitting the second authentication information according to the authentication by the authentication unit 26.

Also, the device 10 has an authentication unit 16 for carrying out the authentication in order to carry out communications with the authentication unit 26 by using the first authentication information that is acquired in advance from the authentication management unit 20, and a communication unit 14 for receiving the second authentication information from the communication unit 25 according to the authentication by the authentication unit 16.

Namely, in this device authentication management system, as shown in FIG. 1, the devices 10a to 10c that have acquired master keys Ma to Mc from the authentication management unit 20 acquire a common key K that is common to the devices 10a to 10c from the authentication management unit 20 by using the acquired master keys Ma to Mc, and the devices 10a to 10c that have acquired that common key K carry out the authentication among the devices 10a to 10e for which the information data transmission and reception are desired, by using the acquired common key K. When the authentication using this common key K succeeds, each of the devices 10a to 10c can carry out the information data transmission and reception with the other device for which the authentication has succeeded.

The above described master key M is the first authentication information (encryption key) to be used for carrying out the communications between the authentication management unit 20 and the device 10. Also, the common key K is a part of the second authentication information (authentication information), which is an encryption key to be used for carrying out communications between the device 10 and the other device 10.

Also, the authentication information is the second authentication information to be used for carrying out communications between the device and the other device 10, which contains the common key (encryption key) K to be used for carrying out the common encrypted authentication between the devices 10, an identifier for identifying the authentication information, and a valid period information indicating the valid period of the authentication information, for example. In addition, the secret information is information including the first authentication information and the second authentication information.

As shown in FIG. 2, the device authentication management system according to this embodiment has devices 10 and the authentication management unit 20.

The device 10 acquires the prescribed secret information from the authentication management unit 20, and carries out the authentication in order to carry out the communications with the other device 10 by using that acquired secret information, and has an operation unit 11, an acquired information storage unit 12, an acquired information management unit 13, a communication unit 14, an authentication information determining unit 15 and an authentication unit 16, in this embodiment.

The operation unit 11 makes input of information data or the like, and can be in a form of a keyboard, for example. Note that the shape of the operation unit 11 can be button-like shape or joystick-like shape. More specifically, when a detection signal for registering information of the device 10 to the authentication management unit 20 is detected, the operation unit 11 outputs the detected detection signal to the acquired information management unit 13.

Also, when an authentication command signal for carrying out the authentication with the authentication management unit 20 entered by the user operation is detected, the operation unit 11 outputs the detected authentication command signal to the acquired information management unit 13. In addition, when a device authentication command signal for carrying out the authentication with each device 10 is entered by the user operation, the operation unit 11 acquires the entered device authentication command signal to the acquired information management unit 13.

The acquired information storage unit 12 stores a plurality of the first authentication information (master key M) and the second authentication information (authentication information), and can be in a form of a hard disk or an IC chip, for example. More specifically, the acquired information storage unit 12 stores the master key M or the authentication information acquired by the acquired information management unit 13 from the communication unit. Note that the acquired information storage unit 12 can also store information data such as characters, facial pictures, etc., to be transmitted to the other device 10.

The acquired information management unit 13 controls the internal operation of the device 10, and can be in a form of a CPU, for example. More specifically, when the detection signal is entered from the operation unit 11, the acquired information management unit 13 produces a registration information corresponding to the detection signal according to the entered detection signal. Then, after producing the registration information, the acquired information management unit 13 outputs the produced registration information as a request signal to the communication unit 14.

Here, the registration information can contain a name of the device 10, a picture of a user who owns the device 10, a name of the manufacturer who manufactured and sold the device 10, a serial number of the device 10, the date on which the user purchased the device 10, PIN (Personal Identification Number), etc., for example. By registering the registration information of the device 10 to the authentication management unit 20, the device 10 can acquire the master key M from the authentication management unit 20 (as will be described below).

When the request signal from the communication unit 14 is received, the authentication management unit 20 makes the registration according to the received request signal such that the device 10 which transmitted that request signal belongs to the radio network of the authentication management unit 20, and distributes the master key M to the device 10 that made the registration. When the master key M transmitted from the authentication management unit 20 is received at the communication unit 14, the acquired information management unit 13 stores the received master key K into the acquired information storage unit 12.

Also, when the authentication command signal is entered from the operation unit 11, the acquired information management unit 13 transmits the entered authentication command signal to the communication unit 14, acquires the master key M corresponding to the entered authentication command signal, and outputs the acquired master key M to the authentication unit 16. When the authentication command signal is entered from the acquired information management unit 13, the communication unit 14 transmits the entered authentication command signal to the communication unit 25.

When the master key M corresponding to the authentication command signal is entered from the acquired information management unit 13, the authentication unit 16 decrypts the common key K that is encrypted by using the master key M transmitted from the communication unit 25 of the authentication management unit 20, by using the entered master key M, and outputs the decrypted common key K to the acquired information management unit 13.

When the decrypted common key K is entered from the authentication unit 16, the acquired information management unit 13 stores the entered common key K into the acquired information storage unit 12. In addition, when the device authentication command signal is entered from the operation unit 11, the acquired information management unit 13 outputs the entered device authentication command signal to the authentication information determining unit 15.

The authentication information determining unit 15 selects the second authentication information in order to carry out communications with the other device 10, and has a valid period judgement unit 15a, a rearrangement unit 15b, and a selection unit 15c in this embodiment.

The valid period judgement unit 15a checks the valid period information contained in the second authentication information (authentication information). More specifically, when the device authentication command signal is entered from the acquired information management unit 13, the valid period judgement unit 15a acquires the common key K stored in the acquired information storage unit 12, judges the valid period (expiration time) of the common key K from the valid period information contained in that common key K, and outputs a judgement signal indicating that the valid period is judged, to the acquired information management unit 13 and the rearrangement unit 15b.

The rearrangement unit 15b rearranges a plurality of the second authentication information corresponding to the valid period information into a prescribed order, according to the valid period information contained in the second authentication information. More specifically, when the judgement signal from the valid period judgement unit 15a is entered, the rearrangement unit 15b rearranges a plurality of the authentication information stored in the acquired information storage unit 12 into a descending order of the valid periods, for example, according to the entered judgement signal, and outputs a rearrangement result signal indicating the rearranged result to the selection unit 15c.

The selection unit 15c selects one second authentication information corresponding to the valid period information from a plurality of the second authentication information containing the valid period information which are stored in the acquired information storage unit 12, according to the valid period information contained in the second authentication information. More specifically, when the rearrangement result signal is entered from the rearrangement unit 15b, the selection unit 15c judges which authentication information among the rearranged authentication information should be used according to the entered rearrangement result signal, and outputs the judged result as a use judgement signal to the acquired information management unit 13.

For example, when the rearrangement result signal is entered, the selection unit 15c selects the authentication information for which the expiration time of the valid period is longest among the authentication information rearranged in the order of the valid periods, according to the entered rearrangement result signal, and judges to use it for the authentication with each device 10.

Also, the selection unit 15c acquires the identifiers contained in a plurality of the second authentication information (common key K) available at the other device 10b, extracts the common identifiers among the acquired identifiers and the identifiers contained in a plurality of the second authentication information available at the device 10a, and selects one second authentication information corresponding to the valid period information among the second authentication information corresponding to the extracted identifiers, according to the valid period information corresponding to these identifiers.

More specifically, first, when the operation unit 11 (of the device 10a) detects the device authentication command signal for carrying out the authentication with the device 10b entered by the user operation, the operation unit 11 outputs the detected device authentication command signal to the acquired information management unit 13.

When the device authentication command signal is entered from the operation unit 11, the acquired information management unit 13 outputs the entered device authentication command signal to the selection unit 15c if it is judged that the entered device authentication command signal is a signal for which the authentication information should be selected according to the identifier contained in the authentication information. Note that, if the entered device authentication command signal a signal for which the authentication information should be selected according to the valid period information contained in the authentication information, the acquired information management unit 13 outputs the entered device authentication command signal to the above described valid period judgement unit 15a.

When the device authentication command signal is entered from the acquired information management unit 13, the selection unit 15c acquires the identifiers (n-3, n-2, n-1, n) of the authentication information corresponding to the device authentication command signal from the acquired information storage unit 13, for example, according to the entered device authentication command signal, and outputs the acquired identifiers (n-3, n-2, n-1, n) to the communication unit 14.

When the identifiers (n-3, n-2, n-1, n) are entered from the selection unit 15c, the communication unit 14 transmits the entered identifiers (n-3, n-2, n-1, n) to the communication unit 14 of the device 10b. On the other hand, the device 10b transmits the identifiers (n-3, n-2, n-1) stored in he acquired information storage unit 12 of the device 10b, for example, to the device 10a that have transmitted the identifiers (n-3, n-2, n-1, n) similarly as in the above described procedure.

When the identifiers (n-3, n-2, n-1) are received from the device 10b, the communication unit 14 of the device 10a outputs the received identifiers (n-3, n-2, n-1) to the selection unit 15c. Then, when the identifiers (n-3, n-2, n-1) are entered from the communication unit 14, the selection unit 15c acquires the identifiers (n-3, n-2, n-1, n) of the authentication information to be used by the own device from the acquired information storage unit 12, and compares the acquired identifiers (n-3, n-2, n-1, n) with the identifiers (n-3, n-2, n-1) entered from the communication unit 14.

When these identifiers are compared, the identifiers (n-3, n-2, n-1) are coinciding, so that the selection unit 11e selects the identifier n-1 with the longest valid period T among the coinciding identifiers (n-3, n-2, n-1), for example. Also, the selection of this identifier n-1 is also carried out by the selection unit 15c of the device 10b by the similar procedure as described above.

When the identifier n-1 is selected, the selection unit 15c acquires the common key Kn-1 corresponding to the selected identifier n-1 from the acquired information storage unit 12, and outputs the acquired common key Kn-1 to the authentication unit 16. Then, when the common key Kn-1 corresponding to the identifier n-1 is entered from the selection unit 15c, the authentication unit 16 encrypts the information data to be transmitted to the device 10b by using the entered common key Kn-1, and the communication unit 14 transmits the information data encrypted by that common key Kn-1 to the device 10b.

Note that when a plurality of the second authentication information generated at a prescribed period by the secret information generation unit 22 are acquired, and the number of the acquired second authentication information exceeds a prescribed number, the selection unit 15c may delete any of the plurality of the acquired second authentication information. In this way, there is no need for the device to manage the valid period of the second authentication information and there is no need to provide a time management unit (not shown) for the purpose of managing the valid period.

The authentication unit 16 carries out the authentication in order to carry out communications with the authentication unit 26 by using the first authentication information (master key M) that is acquired in advance from the authentication management unit 20. More specifically, the authentication to be carried out at the authentication unit 16 can be explained by using the OSI network model as shown in FIG. 3. According to FIG. 3, the common key K common between the device 10a and the device 10b is encrypted by using the master key M at the application layer of the OSI model at the authentication management unit 20 first. Note that the common key K is generated by the secret information generation unit 22 (as will be described in detail below).

When the common Key K encrypted by using the master key M is acquired (at the communication unit 14), the device 10a decrypts the common key K encrypted by using the master key M at the application layer of the OSI model at the authentication unit 16 of the device 10a, by using the master key M entered from the acquired information management unit 13. When the common key K is decrypted, the authentication unit 16 outputs the decrypted common key K to the acquired information management unit 13, and when the common key K is entered from the authentication unit 16, the acquired information management unit 13 stores the entered common key K into the acquired information storage unit 12.

Also, the authentication unit 16 carries out the authentication in order to carry out communications with the other device 10b by using the second authentication information (common key K) received at the communication unit 14. More specifically, in the case of carrying out the authentication in order to carry out communications between the device 10a and the device 10b, the authentication unit 16 acquires the common key K common to the device 10a and the device 10b from the selection unit 15c. When the common key K is acquired, the authentication unit 16 encrypts information data (character data, image data, etc., for example) to be transmitted to the device 10b at the datalink layer of the OSI model, by using the acquired common key K.

When the information data are encrypted by using the common key K, the authentication unit 16 transmits the information data encrypted by using the common key K from the communication unit 14 through the datalink layer of the OSI model. When the information data encrypted by using the common key K are acquired from the device 10a, the authentication unit 14 of the device 10b decrypts the information data encrypted by using the common key K, by using the common key K provided in advance at the device 10b.

In this way, the common key K is distributed to all the devices 10 (10a, 10b) registered at the authentication management unit 20, so that the device 10a that has the common key K can transmit information data by encrypting them by using the common key K with respect to the other device 10b that also has the common key K, and therefore the leakage of the prescribed information data to the external party can be prevented.

The communication unit 14 receives the second authentication information from the communication unit 25 of the authentication management unit 20 according to the authentication of the authentication unit 16. The communication unit 14 can be in a form of a communication device using the communication scheme based on the Bluetooth, a communication device using the communication scheme based on the IEEE 802.11 or IrDA, etc., for example.

More specifically, when the authentication command signal is entered from the acquired information management unit 13, the communication unit 14 transmits the entered authentication command signal to the communication unit 25 of the authentication management unit 20. When the common key K encrypted by using the waster key M corresponding to the authentication command signal is received from the communication unit 25, the communication unit 14 outputs the received authentication information encrypted by using the master key M to the authentication unit 16.

When the authentication information encrypted by using the master key M is entered from the communication unit 14, the authentication unit 16 decrypts the entered authentication information encrypted by using the master key M, by using the master key M entered from the acquired information management unit 13, and outputs the decrypted authentication information to the acquired information management unit 13, and when the decrypted authentication information is entered, the acquired information management unit 13 stores the entered authentication information into the acquired information storage unit 12.

Also, when the request signal is entered from the acquired information management unit 13, the communication unit 14 transmits the entered request signal to the communication unit 25 of the authentication management unit 20. In addition, when the master key M corresponding to the request signal is received from the authentication management unit 20, the communication unit 14 outputs the received master key M to the acquired information management unit 13.

When the master key M is entered from the communication unit 14, the acquired information management unit 13 stores the entered master key M into the acquired information storage unit 12. Then, when the device authentication command signal is entered from the operation unit 11, the acquired information mana