JP2011077740A - Key information management apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve security when encrypting and utilizing data. <P>SOLUTION: The key information management apparatus 10 is composed of a tamper-resistant apparatus which is excellent in security and is attachable and detachable to/from a PC 5, and stores a memory 16 and a timer 15 etc. The key information management apparatus 10 downloads an encryption key 17 for encrypting data stored in the storage medium 6 of the PC 5 from a management server 20 and tentatively stores it in the memory 16. The timer 15 deletes the tentatively stored encryption key 17 in the stage that there is no access from a user to the key information management apparatus 10 for a fixed period of time. In the stage that the encryption key 17 is deleted, it becomes impossible to decrypt the data stored by the PC 5. User authentication is performed for access from the PC 5 to the key information management apparatus 10, the time runs out while a third person is attacking the user authentication to steal the encryption key 17, and the encryption key 17 is deleted. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a key information management device, for example, to a device that manages key information used by encrypting data.

With the spread of IT technology, the digitization of information is progressing, and since the digitized data can be easily copied and transmitted, there is a problem of how to increase the security of the digitized data.
For this reason, a technique for encrypting and storing data in a storage medium such as a hard disk is used.
In this technique, an encryption key used for data encryption / decryption is stored in a computer, and the encryption key can be used by user authentication by inputting a password or the like. The authenticated user decrypts and uses the data with the encryption key, and encrypts and stores the data after use.

  Also, as in the “file data deletion program and file data deletion system” disclosed in Patent Document 1, time information is added to the file data, and this is used to restrict file opening, or Techniques for improving security by deleting the content have also been proposed.

However, since conventional computers perform user authentication, but the encryption key is stored in the computer, there is a vulnerability that even if the data is encrypted, the data is decrypted by attacking the authentication function. there were.
It is also possible to store the encryption key in a storage medium that can be attached to and detached from the computer and manage it separately from the computer. For example, a notebook PC (Personal computer) and a storage medium are placed in the same bag. It is not always managed separately, and further security needs to be improved.
Further, the technique disclosed in Patent Document 1 has a problem that file data providers and recipients need to have dedicated applications, which are not suitable for general users of PCs on a daily basis.

JP 2005-316903 A

  An object of the present invention is to enhance security when data is encrypted and used.

In order to achieve the above object, according to the present invention, in the first aspect of the present invention, key information acquisition means for acquiring key information, key information storage means for storing the acquired key information, and the stored key Confirmation means for confirming that the provision destination of information is an appropriate provision destination, and key information provision means for providing the stored key information to the provision destination when the provision destination is confirmed to be appropriate; A key information management comprising: a measuring unit that measures a time elapsed from a predetermined time; and an erasing unit that erases the stored key information when the measured time has passed the predetermined time. Providing the device.
According to a second aspect of the present invention, there is provided the key information management apparatus according to the first aspect, wherein the key information acquisition unit acquires the key information from a predetermined information processing apparatus.
According to a third aspect of the present invention, there is provided the key information management apparatus according to the first or second aspect, further comprising a predetermined time setting unit for setting the predetermined time.
According to a fourth aspect of the present invention, the key information management device is configured to be detachable from the provision destination, and the key information management according to the first, second, or third aspect of the present invention. Providing the device.
In the invention according to claim 5, after the confirmation means confirms that the provision destination is an appropriate provision destination, an extension means for extending the time point at which the erasure means erases the stored key information is provided. A key information management device according to any one of claims 1 to 4 is provided.
The invention according to claim 6 is characterized in that each of the means is formed inside a tamper-proof device, and the key information management according to any one of claims 1 to 5 Providing the device.

  According to the present invention, since the encryption key is deleted after a predetermined time has elapsed, security can be improved when data is encrypted and used.

It is a figure for demonstrating the structure of the encryption key time limit control system of this embodiment. It is a figure for demonstrating the time limit management of the encryption key which a timer part performs. It is a flowchart for demonstrating the procedure in which a key information management apparatus downloads an encryption key. It is a flowchart for demonstrating the procedure in case a key information management apparatus operate | moves in uniform erase mode. It is a flowchart for demonstrating the procedure in case a key information management apparatus operate | moves in reset mode.

(1) Outline of Embodiment The key information management device 10 (FIG. 1) is composed of a tamper-proof device having excellent confidentiality and detachable from the PC 5, and stores a memory 16, a timer unit 15, and the like. Note that the key information management apparatus 10 may be built in the PC 5.
The key information management apparatus 10 downloads an encryption key 17 for encrypting data stored in the storage medium 6 of the PC 5 from the management server 20 and temporarily stores it in the memory 16.
The timer unit 15 erases the temporarily stored encryption key 17 when there is no user access to the key information management apparatus 10 for a certain period of time (referred to as “erasure time”). When the encryption key 17 is erased, the data stored in the PC 5 cannot be decrypted.

  Access to the key information management device 10 from the PC 5 is performed by user authentication. Even if the key information management device 10 passes to a third party, the third party attacks the user authentication and steals the encryption key 17. Since the encryption key 17 is deleted due to time-out while trying to work, security can be improved.

The erasure time can be set according to the situation by the user, is short when enhancing the security, moves the PC 5 to an environment where the management server 20 cannot be connected, or saves the trouble of downloading the encryption key 17. Make it long.
Further, when the user accesses the key information management device 10, the time measurement of the timer unit 15 is reset, and the encryption key 17 is stored in the key information management device 10 as long as the user uses the encryption key 17 within the erasure time. It is also possible to save and reduce the number of accesses to the management server 20.

(2) Details of Embodiment FIG. 1 is a diagram for explaining the configuration of the encryption key time limit control system 1 of the present embodiment.
The encryption key time limit control system 1 includes a PC 5, a key information management device 10, a communication network 3, a management server 20, and the like.
Among these, for example, the PC 5 and the key information management device 10 are managed by the user, and the management server 20 is managed by the management center.

The PC 5 is a portable notebook PC and stores data (files) in a storage medium 6 such as a built-in hard disk.
The PC includes a storage medium 6 composed of a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk, and the like.
In this embodiment, the PC 5 is a notebook type, but this is only an example, and it may be a desktop type or other stationary type, or a palmtop or other smaller PC. May be.

The PC 5 includes an encryption processing unit that encrypts and decrypts data in the storage medium 6 using the encryption key 17. When the user uses the data in the storage medium 6, the PC 5 uses the encryption key 17. When the data is decrypted and stored in the storage medium 6 after use, it is encrypted after using the encryption key 17 and stored.
As described above, since the data in the storage medium 6 is stored in an encrypted state using the encryption key 17, the third party decrypts the data in the storage medium 6 unless the encryption key 17 is obtained. Can not do it.

The key information management device 10 is a device (HSM: Hardware Security Module) having a tamper-resistant structure for storing and managing the encryption key 17 for a time limit, and includes a communication unit 11, a memory 12, a CPU 14, a timer unit 15, a memory 16, a battery 18 etc. are provided.
Although not shown, the key information management apparatus 10 includes an interface for connecting to an external connection interface of the PC 5 and is configured to be detachable from the PC 5.

The memory 12 is a storage medium (internal memory) composed of a semiconductor, and corresponds to the device secret key 13 (the device public key 24 of the management server 20) used by the management server 20 to authenticate the key information management device 10. A secret key), a server public key 27 for authenticating the management server 20 by the key information management apparatus 10 (a public key corresponding to the server secret key 25 of the management server 20), and the like. These pieces of information are stored in the memory 12 at the time of factory shipment, for example.
The digital signature value 28 is generated when the time stamp device 10 requests authentication from the management server 20 as will be described later.
The memory 12 also stores a common key 19 using random numbers generated for communication with the management server 20 by the key information management apparatus 10, a key information management program executed by the CPU 14, and the like.

The memory 16 is a storage medium (internal memory) composed of a semiconductor, and stores an encryption key 17 that is key information for the PC 5 to encrypt and decrypt data in the storage medium 6.
The encryption key 17 is downloaded from the management server 20 by the CPU 14 and temporarily stored in the memory 16.
In the key information management apparatus 10, for example, the memory 16 is configured as another storage medium, such as the memory 12 is configured with SRAM (Static Random Access Memory) and the memory 16 is configured with DRAM (Dynamic Random Access Memory). It may be a storage medium.

The CPU 14 performs various types of information processing such as management of the encryption key 17 and mutual authentication processing with the PC 5 and the management server 20 according to the key information management program, and control of each part of the key information management apparatus 10.
The timer unit 15 is a functional unit configured by software using an internal clock of the key information management device 10 (not shown) by the CPU 14 executing a key information management program, measures the passage of time, and performs a predetermined time. When elapses, the encryption key 17 is deleted. Hereinafter, this predetermined time is referred to as an erasing time.

  A key information management application for using the key information management apparatus 10 is installed in the PC 5, and the application is operated while the key information management apparatus 10 is connected to the PC 5, thereby performing user authentication and encryption. The key 17 can be taken out and an erasing time can be set.

In the erasing timing, a mode in which the encryption key 17 is stored in the memory 16 and the erasing time is uniformly erased after the erasing time has elapsed (a uniform erasing mode), and a mode in which time measurement is reset every time the PC 5 uses the encryption key 17 ( Reset mode).
These two modes may be configured so that the user can set them using the key information management application, or the key information management apparatus 10 may be configured to operate only in one of the modes.

The communication unit 11 communicates with the management server 20 via the communication network 3.
For example, the communication unit 11 is connected to the access point of the communication network 3 by wireless communication, but may be configured to be connected by wire.
In this embodiment, the communication unit 11 is provided in the key information management device 10. However, when the PC 5 has a communication function using the communication network 3, the key information management device 10 uses the communication function of the PC 5. It can also be configured to communicate with the management server 20.

The battery 18 is a battery for supplying power to the CPU 14 and other components of the key information management apparatus 10 to drive the key information management apparatus 10 alone, and the key information management apparatus 10 is detached from the PC 5. Even in this case, the key information management apparatus 10 operates with the power supplied from the battery 18, and can measure the elapsed time by the timer unit 15 and erase the encryption key 17.
When the key information management apparatus 10 is connected to the PC 5, the key information management apparatus 10 receives power from the PC 5 and suppresses the consumption of the battery 18.
Alternatively, the battery 18 can be charged by the power supplied from the PC 5.

The key information management device 10 has a tamper-resistant structure so that unauthorized operation from the outside cannot be performed. If an attempt is made to analyze the contents of the key information management device 10 from the outside, it is stored in the memory 12 or the memory 16. Some information is automatically deleted.
For this purpose, the power supplied from the battery 18 to the memories 12 and 16 is supplied via a coil stretched around the casing of the key information management apparatus 10. When the contents are analyzed by physically opening the coil, the coil is disconnected, the power of the memories 12 and 16 is interrupted, and the stored contents such as the device secret key 13 and the encryption key 17 are erased.
In addition to such physical analysis, for example, erasure may be performed for software analysis, such as erasure when user authentication fails a predetermined number of times.

The management server 20 is a server that transmits the encryption key 17 to the key information management apparatus 10.
The management server 20 includes a storage medium including a CPU, a RAM, a ROM, a hard disk, and the like, and a communication unit 21, an authentication unit 22, an encryption key DB (database) 23, and the like are formed using these. .
The communication unit 21 communicates with the communication unit 11 via the communication network 3 and performs communication at the time of mutual authentication with the key information management apparatus 10 and transmission of the encryption key 17.

The authentication unit 22 mutually authenticates the key information management device 10 and identifies the key information management device 10.
Upon receiving the digital signature value 28 encrypted with the device private key 13 from the key information management device 10, the authentication unit 22 decrypts the digital signature value 28 with the device public key 24 and determines whether the key information management device 10 is an appropriate device. Certify.
The identification of the key information management apparatus 10 is performed by transmitting information unique to the key information management apparatus 10 (such as the device ID of the key information management apparatus 10) to the management server 20, for example.

Further, the authentication unit 22 encrypts the digital signature value 29 generated from its own server ID information with its own server private key 25 and transmits it to the key information management apparatus 10, and sends it to the key information management apparatus 10 using the server public key 27. The management server 20 is authenticated by decrypting.
This authentication technique uses a so-called PKI (Public Key Infrastructure) technique.
The encryption key timed control system 1 employs two-factor authentication, and the authentication unit 22 also authenticates user authentication information 26 (user ID, password, PC information, etc.).

The encryption key DB 23 is stored in a storage medium, and stores the encryption key 17 in association with the key information management apparatus 10 (for example, device ID). When the management server 20 identifies the key information management device 10 by authentication, the management server 20 acquires the encryption key 17 of the key information management device 10 from the encryption key DB 23 and encrypts it with the common key 19 acquired from the key information management device 10. To the key information management apparatus 10.
The encryption key 17 transmitted to the key information management apparatus 10 is decrypted by the common key 19 of the key information management apparatus 10 and stored in the memory 16.

In the present embodiment, the PC 5 and the key information management device 10 are separated and configured to be detachable. However, the key information management device 10 may be built in the PC 5.
When the key information management device 10 and the PC 5 are separated, the security is improved because the encryption key 17 does not exist inside the PC 5, and a single key information management device 10 can be used by a plurality of PCs 5.
On the other hand, when the key information management device 10 is built in the PC 5, it is possible to save the user from having to detach and store the key information management device 10.

Each drawing in FIG. 2 is a diagram for explaining the time management of the encryption key 17 performed by the timer unit 15.
FIG. 2A shows a case where the timer unit 15 operates in the uniform erase mode. As an example, it is assumed that the erase time is set to 12 hours.
When the CPU 14 downloads the encryption key 17 from the management server 20 and stores it in the memory 16, the timer unit 15 starts measuring the elapsed time and reaches the erasure time (here, 12 hours) regardless of the use state of the encryption key 17. Then, the encryption key 17 is erased.

In this way, in the uniform erasure mode, the encryption key 17 is erased after the erasure time after downloading the encryption key 17, so the time that the encryption key 17 is stored in the key information management device 10 is limited to the erasure time. Can increase security.
Further, as the erasure time is set shorter, the time during which the encryption key 17 is stored in the key information management apparatus 10 can be shortened, so that the security can be further improved.
The erase time can be set to 0 seconds at the shortest. In this case, when the PC 5 requests the encryption key 17, the key information management apparatus 10 downloads the encryption key 17 from the management server 20 and transmits it to the PC 5, and does not store the encryption key 17 in the memory 16.

FIG. 2B shows a case where the timer unit 15 operates in the reset mode. As an example, it is assumed that the erase time is set to 12 hours.
In this case, the timer unit 15 starts measuring the elapsed time when the CPU 14 downloads the encryption key 17 from the management server 20 and stores it in the memory 16. If the PC 5 uses the encryption key 17 before the erasure time elapses, the elapsed time Is reset to 0 and elapsed time measurement is restarted. When the erasing time has elapsed without using the encryption key 17, the timer unit 15 deletes the encryption key 17.

In this way, in the reset mode, the elapsed time measurement is reset every time the PC 5 uses the encryption key 17, so as long as the user uses the key information management device 10 within the erasure time, the encryption key 17 is It is not erased from the key information management device 10.
Therefore, the case where the encryption key 17 is downloaded from the management server 20 is reduced, and the information processing load of the key information management device 10 and the management server 20 and the communication load of the communication network 3 can be reduced.
Since the encryption key 17 is deleted when the deletion time elapses without using the encryption key 17, the security of the management of the encryption key 17 can be improved.

FIG. 2C shows a case where the erase time is set to 6 hours in the reset mode.
In this case, the timer unit 15 resets the measurement of elapsed time when the PC 5 uses the encryption key 17 within 6 hours after the encryption key 17 is downloaded, and 6 hours without using the encryption key 17. When it elapses, the encryption key 17 is deleted.
Thus, if the erasure time is shortened, the possibility that the encryption key 17 is erased due to non-use increases, but the time that the key information management apparatus 10 is stored in the encryption key 17 is shortened. Can reduce the risk of leakage.

In the reset mode described above, the reset is performed when the encryption key 17 is used, but the reset is performed when the erase time elapses on condition that the encryption key 17 is used within the erase time. You can also
In this case, for example, assuming that the erasure time is 12 hours, when the encryption key 17 is used within the 12 hours, the erasure time is further extended by 12 hours when the 12 hours have elapsed.
Further, the number of resets can be limited to a predetermined number. For example, when the number of resets is limited to three, the key information management apparatus 10 extends the erasure time up to three times, but erases the encryption key 17 without performing the fourth reset.

As described above, the erasure time can be arbitrarily set in both the uniform erasure mode and the reset mode. However, the shorter the erasure time, the higher the security, but the more the encryption key 17 is erased. The erasing time can be set according to the usage situation.
For example, when the PC 5 is used in a high-security office, the erasure time is set to about 12 to 18 hours. Time) Set the erase time.

  For example, assuming that the PC 5 and the key information management device 10 are put in the same bag and go on a business trip and the bag is stolen by a third party, the encryption key 17 stored in the key information management device 10 is protected by user authentication. Therefore, the erasure time elapses and the encryption key 17 is erased while a third party is working to obtain the encryption key 17 by releasing or avoiding the protection. Thus, since the encryption key 17 does not remain in the key information management apparatus 10, extremely high security can be realized.

As specific usage forms, for example, the following cases are conceivable.
The user of PC5 usually works from 9 to 5 in a secure office. The user normally sets the erasure time to 6 hours, goes to work before 9 o'clock, downloads the encryption key 17 to the key information management apparatus 10, and uses it while resetting the encryption key 17 until he leaves the office. To do.

After use, the user leaves the key information management device 10 from the PC 5 and stores the key information management device 10 in a desk drawer and locks it, or stores it in a safe designated by the company.
Even if the PC 5 is stolen at night, the data cannot be decrypted because there is no key information management device 10.
Even if both the PC 5 and the key information management device 10 are stolen, the data cannot be decrypted because the timer unit 15 erases the encryption key 17 at night.

Next, it is assumed that the user brings a PC 5 to the customer and makes a presentation.
If the customer can connect to the communication network 3, the encryption key 17 is deleted, the key information management device 10 is brought to the customer, and the key information management device 10 is downloaded at the customer. Security is enhanced because the key 17 is not carried.
On the other hand, if it is usually unknown whether the customer can connect to the communication network 3, the encryption key 17 is stored in the key information management device 10 and carried to the customer.
When the presentation at the customer is 2 hours later, the user sets the erasure time to about 3 hours, carries the PC 5 and the key information management device 10 and moves to the customer.
In this way, the user can set the erase time longer than the scheduled use time and without being too long while comparing the scheduled use time and the erase time of the encryption key 17.

Then, the user connects the key information management device 10 to the PC 5 at the customer, reads the encryption key 17 from the key information management device 10 to the PC 5, decrypts the data, and gives a presentation.
Even if the user loses the PC 5 and the key information management apparatus 10 on the way to the customer, the encryption key 17 is erased in about 3 hours, so that leakage of data can be prevented.
Even if the user loses the PC 5 and the key information management device 10 on the way from the customer to the office, the encryption key 17 is erased by the end of the presentation, thus preventing data leakage. can do.
Needless to say, leakage of data can be prevented even if the PC 5 is lost alone.

  In this way, security is enhanced by separating the PC 5 and the key information management device 10 from each other, and further security is enhanced by setting an erasure time for the encryption key 17, and further, the erasure time can be varied depending on the situation By setting to, user convenience can be achieved while maintaining high security.

FIG. 3 is a flowchart for explaining a procedure in which the key information management apparatus 10 downloads the encryption key 17 from the management server 20.
In the following flowchart, the processing performed by the PC 5, the key information management device 10, and the management server 20 is performed by the CPU of the PC 5, the CPU 14, and the CPU of the management server 20, respectively, according to a predetermined program.

First, the key information management apparatus 10 is connected to the PC 5, and the key information management application is activated on the PC 5 (step 5).
This activation may be activated by the user operating the PC 5 or may be activated automatically when the PC 5 detects the connection of the key information management apparatus 10.
When the key information management application is activated, the PC 5 and the key information management apparatus 10 perform mutual authentication between the PC 5 and the key information management apparatus 10 as follows (step 10).
This mutual authentication is performed using two-factor authentication of user authentication and device authentication performed by the key information management apparatus 10 and the PC 5 with respect to each other.

First, the PC 5 displays a user authentication information input screen on the display of the PC 5, and the user inputs his / her user ID and password.
When receiving the user authentication information from the user, the PC 5 transmits it to the key information management apparatus 10.
Note that, as user authentication information, for example, other information such as biometric information such as veins and fingerprints may be used.

The key information management apparatus 10 stores user authentication information in the memory 12 in advance, and when user authentication information is input from the PC 5, the user authentication information is collated with the user authentication information stored in the memory 12 for user authentication. Do.
If the user authentication fails, the key information management apparatus 10 notifies the PC 5 to that effect and does not accept access from the PC 5.

If the mutual authentication is successful, the key information management apparatus 10 checks whether or not the encryption key 17 is stored in the memory 16 (step 15).
When the encryption key 17 is stored (step 15; Y), the key information management apparatus 10 performs processing described later with reference to FIGS.
When the encryption key 17 is not stored (step 15; N), the key information management apparatus 10 uses the communication unit 11 to connect to the management server 20 and performs mutual authentication (step 20).
Note that the key information management apparatus 10 and the management server 20 encrypt a communication path by the communication network 3 using a technology such as SSL (Secure Sockets Layer) to prevent leakage of communication contents.

In this mutual authentication, the key information management apparatus 10 and the management server 20 confirm that the other party is appropriate by mutually authenticating the other party.
First, when the management server 20 authenticates the key information management apparatus 10, the key information management apparatus 10 generates a common key 19 (random number value) used for encrypted communication and encrypts it with the server public key 27. Subsequently, the key information management device 10 encrypts the user authentication information 26 input from the client terminal 5 with the common key 19, and further encrypts the hashed value of the user authentication information 26 with the device secret key 13. The value 28 is generated. The encrypted information (common key 19, user authentication information 26, digital signature value 28, and device ID of the key information management apparatus 10) is transmitted to the management server 20.

The management server 20 specifies the key information management device 10 by the device ID, and specifies the device public key 24 and the digital signature value 28 used for authentication.
Then, the management server 20 performs authentication of user authentication information and device authentication of the key information management device 10 using the stored device public key 24 and server secret key 25.
First, the management server 20 decrypts the common key 19 encrypted with the server public key 27 with the server secret key 25 and extracts the common key 19 necessary for communication.
In general, encryption processing using a common key is less efficient than encryption processing using an asymmetric key (secret key, public key) and is more efficient, so the key information management device 10 and the management server 20 are: First, the common key 19 is shared using the server public key 27 and the server private key 25, and thereafter, encryption communication is performed using the common key 19.

Next, the management server 20 decrypts the user authentication information encrypted with the common key 19 on the key information management apparatus 10 side using the common key 19, and then digitally encrypted with the apparatus private key 13. The signature value 28 is decrypted with the device public key 24.
Then, the management server 20 verifies the key information management apparatus 10 based on the decrypted user authentication information 26 and the digital signature value 28. If the verification is successful, the processing is continued. If the verification fails, the connection request is rejected because the user authentication information 26 or the key information management device 10 is invalid.
As described above, the management server 20 enhances security by authenticating the key information management device 10 by two-factor authentication based on the user authentication information 26 and the device information (device secret key 13, digital signature value 28).

On the other hand, when the key information management apparatus 10 authenticates the management server 20, the management server 20 uses a digital signature value 29 encrypted with the server private key 25 for the hashed value of the management server ID information as the key information management apparatus. 10 to send.
The key information management apparatus 10 decrypts this with the server public key 27 to extract the digital signature value 29 and verifies the management server 20. If the verification is successful, the processing is continued. If the verification fails, the connection request is rejected because the management server 20 is invalid.
As described above, the key information management apparatus 10 and the management server 20 perform mutual authentication by authentication using PKI and two-factor authentication.

When the key information management device 10 and the management server 20 perform mutual authentication, the management server 20 searches and acquires the encryption key 17 corresponding to the key information management device 10 in the encryption key DB 23, and encrypts this with the common key 19. And transmitted to the key information management apparatus 10 (step 25).
When receiving the encryption key 17 from the management server 20, the key information management device 10 decrypts it with the common key 19 and stores it in the memory 16 (step 30).
When the encryption key 17 is stored in the memory 16, the timer unit 15 starts measuring elapsed time (step 35).

As described above, when there is no encryption key 17 in the memory 16, the key information management apparatus 10 can download the encryption key 17 from the management server 20 and store it in the memory 16 after mutual authentication with the management server 20. .
Therefore, even when the encryption key 17 is erased due to the erasure time or the like, the encryption key 17 can be obtained again via the network, and the user can use the encrypted data of the PC 5.

  In the present embodiment, the encryption key 17 is downloaded from the management server 20. However, for example, the user stores the encryption key 17 in a predetermined storage medium and stores it in a safe place such as a safe. Alternatively, when the encryption key 17 of the key information management apparatus 10 is erased, a method of copying the encryption key 17 from the predetermined storage medium to the key information management apparatus 10 is also possible.

FIG. 4 is a flowchart for explaining a procedure when the key information management apparatus 10 operates in the uniform erasure mode.
The same steps as those in FIG. 3 are given the same step numbers to simplify the description.
In the key information management apparatus 10, the timer unit 15 monitors whether the erasure time has elapsed since the encryption key 17 was downloaded (step 40). If not, the timer unit 15 monitors (step 40; N). If the process continues and elapses (step 40; Y), the encryption key 17 is deleted from the memory 16 (step 45).

Activation of the key information management application (step 5) and mutual authentication between the PC 5 and the key information management apparatus 10 are the same as the processing in FIG.
After mutual authentication, the key information management apparatus 10 checks whether or not the memory 16 stores the encryption key 17 (step 15). If not stored (step 15; N), the step of FIG. The download process of the encryption key 17 shown in 20 to 35 is performed (step 60).
When the memory 16 stores the encryption key 17 (step 15; Y), or after downloading the encryption key 17 (step 60), the key information management device 10 transmits the encryption key 17 to the PC 5 (step 60). 65).

When receiving the encryption key 17 from the key information management apparatus 10, the PC 5 stores it in a predetermined area of its own memory (for example, main memory) (step 70).
When the user reads data from the storage medium 6, the PC 5 decrypts the data with the stored encryption key 17. When storing data in the storage medium 6, the PC 5 encrypts the data with the stored encryption key 17. The data is encrypted / decrypted with the encryption key 17 (step 75).
When the user finishes using the data in the storage medium 6 (step 80), the PC 5 erases the encryption key 17 stored in its own memory (step 85).

In the above example, the PC 5 is configured to acquire and store the encryption key 17 from the key information management apparatus 10 and use it. However, each time the encryption key 17 is used, the PC 5 transmits it from the key information management apparatus 10. It can also be configured not to be stored in the PC 5.
In this case, since the encryption key 17 is not stored in the PC 5, security can be further improved.

The key information management apparatus 10 can also be configured to delete the encryption key 17 stored in the memory 16 after transmitting the encryption key 17 in step 65.
In this case, since the encryption key 17 does not exist in the key information management apparatus 10 after transmitting the encryption key 17 to the PC 5, security can be further improved.

FIG. 5 is a flowchart for explaining a procedure when the key information management apparatus 10 operates in the reset mode.
The same steps as those in FIG. 4 are given the same step numbers to simplify the description.
The processing performed by the PC 5 (steps 5 to 85) and the processing until the key information management apparatus 10 transmits the encryption key 17 to the PC 5 (steps 15 to 65) are the same as those in FIG.
In the reset mode, when the key information management apparatus 10 transmits the encryption key 17 to the PC 5, it issues a reset command to the timer unit 15 (step 110).

The timer unit 15 monitors whether a reset command has been issued (step 115), and if there is a reset command (step 115; Y), resets the elapsed time measurement (step 120).
Further, the timer unit 15 confirms whether the erasure time has elapsed (step 40) after the reset command has not been received (step 115; N) or after being reset (step 120), and the erasure time has not elapsed. (Step 40; N), the process returns to Step 115, and if the erasure time has elapsed (Step 40; Y), the encryption key 17 is erased (Step 45).

  In the above example, after transmitting the encryption key 17 (step 65), the key information management device 10 issues a reset command (step 110). The timing for issuing the reset command is immediately after mutual authentication (step 10). But you can.

According to the embodiment described above, the following effects can be obtained.
(1) An important encryption key 17 is stored by using a management server 20 that stores a timer unit 15 and a memory 16 in a key information management device 10 configured with HSM having excellent confidentiality and communicates with the key information management device 10. Can be safely distributed and stored.
(2) The key information management apparatus 10 uses the timer unit 15 to erase the temporarily recorded encryption key 17 when there is no access from the user for a certain time or more. When the encryption key 17 is erased, the data of the PC 5 cannot be decrypted, so that the data can be protected.
(3) If the PC 5 is not used for a certain time or more, for example, if the PC 5 is portable, etc., the encryption key 17 will be lost when the erasure time after losing elapses. Even if successful, the data cannot be decrypted.
(4) Since the PC 5 and the key information management device 10 are stored separately, there is no fear of receiving an authentication attack after the PC 5 is lost unless it is lost at the same time.
(5) By performing user authentication, time can be earned when receiving an authentication attack, and the encryption key 17 can be extinguished during that time.

According to the present embodiment described above, the following configuration can be obtained.
For example, the key information management device 10 acquires the encryption key 17 by downloading it from the key information management device 10 and stores it in the memory 16, so that the key information acquisition unit acquires key information (encryption key 17). And key information storage means (memory 16) for storing the acquired key information.
Further, the key information management apparatus 10 transmits the encryption key 17 to the PC 5 after confirming whether the user of the PC 5 is appropriate by user authentication, and confirming that the PC 5 is appropriate by authenticating the PC 5. Confirmation means for confirming that the provision destination of the stored key information is an appropriate provision destination, and key information provision for providing the stored key information to the provision destination when the provision destination is confirmed to be appropriate Means.
Furthermore, the key information management device 10 measures the time elapsed by the timer unit 15 and deletes the encryption key 17 stored in the memory 16 when the deletion time has elapsed, Measuring means (timer unit 15) for measuring the time elapsed since downloading or resetting, and erasing means for erasing the stored key information when the measured time has passed a predetermined time (erasing time) A timer unit 15) is provided.

Since the key information management apparatus 10 downloads the encryption key 17 from the management server 20, the key information acquisition unit acquires the key information from a predetermined information processing apparatus (management server 20).
Further, since the user can set the erasure time, the key information management apparatus 10 includes a predetermined time setting means for setting the predetermined time.
Since the key information management apparatus 10 can be attached to and detached from the PC 5, the key information management apparatus is configured to be attachable to and detachable from the providing destination (PC 5).
Further, in the reset mode, when user authentication is successful (further, a condition such as after the encryption key 17 is transmitted to the PC 5 can be added), the time point at which the encryption key 17 is erased is reset by resetting the time measurement. Since the confirmation means confirms that the provision destination is an appropriate provision destination, the confirmation means includes an extension means for extending the time point at which the erasure means erases the stored key information.
In the key information management apparatus 10, since each functional unit is formed in a tamper-resistant HSM, a key information acquisition unit, a key information storage unit, a confirmation unit, a key information provision unit, a measurement unit, a deletion unit, a predetermined unit, Each of the time setting means and the extension means is formed inside the tamper resistant device.

1 Cryptographic key time limit control system 3 Communication network 5 PC
6 Storage Medium 10 Key Information Management Device 11 Communication Unit 12 Memory 13 Device Secret Key 14 CPU
DESCRIPTION OF SYMBOLS 15 Timer part 16 Memory 17 Encryption key 18 Battery 19 Common key 20 Management server 21 Communication part 22 Authentication part 23 Encryption key DB
24 device public key 25 server private key 26 user authentication information 27 server public key 28 digital signature value 29 digital signature value

Claims (6)

Key information acquisition means for acquiring key information;
Key information storage means for storing the acquired key information;
Confirmation means for confirming that the provision destination of the stored key information is an appropriate provision destination;
Key information providing means for providing the stored key information to the providing destination when the providing destination is confirmed to be appropriate;
A measuring means for measuring time elapsed from a predetermined time point;
Erasing means for erasing the stored key information when the measured time has passed a predetermined time;
A key information management device comprising:   The key information management apparatus according to claim 1, wherein the key information acquisition unit acquires the key information from a predetermined information processing apparatus.   3. The key information management apparatus according to claim 1, further comprising a predetermined time setting unit that sets the predetermined time.   The key information management apparatus according to claim 1, wherein the key information management apparatus is configured to be detachable from the provision destination.   2. The apparatus according to claim 1, further comprising an extension means for extending a time point at which the erasure means erases the stored key information after the confirmation means confirms that the provision destination is an appropriate provision destination. The key information management device according to any one of claims 4 to 4.   6. The key information management device according to claim 1, wherein each of the means is formed inside a tamper-proof device.

Images