JP3012130B2 - Data delivery method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data delivery method for transmitting and receiving data via a network, and more particularly, to encrypting and transmitting data on a data provider side and decrypting encrypted data on a data user side. It relates to a data delivery method that is used in the form of data.

[0002]

2. Description of the Related Art In a data delivery system for transmitting and receiving data via a network, the number of data users and the period of access to the data by a system arranged on the user side via the network are determined by the data provider. Sometimes you want to know or manage.

[0003] In response to this demand, there is the following prior art.

(1) Data user access history information is stored as a file in an auxiliary storage device on the data user side. The contents of the history information file are periodically taken out from the data provider via the network, or transferred periodically from the data user via the network.

(2) Each time a data user accesses data, a message notifying the fact is transmitted to the data provider via the network, and the contents of the message are stored in the auxiliary storage device of the data provider. Save as a history information file.

However, the contents of the history information file created as described above may be intentionally falsified or hidden by the data user.

Therefore, there is the following technique as a method for preventing the falsification or hiding of the history information file.

(1) By encrypting the history information file stored on the auxiliary storage device on the data user side,
Prevent tampering.

(2) Data is transferred via the network each time a data user requests access, and is discarded after access is completed, thereby preventing concealment of access history information.

(3) By preventing access history information from being falsified or concealed by storing the access history information using a device having a limited interface such as an IC card.

In addition, "Nikkei Computer" (193)
There is a method used for the “identification and authentication system” in 3.11.1, p.72 to p.73).

[0012]

However, in these methods, access to data can be performed irrespective of the history, and after the data user accesses the data, the history information file is changed to the past. There is a problem that the data access history information can be hidden by a simple operation on the data user side, for example, by replacing the history information or preventing the transfer of the history information through the network.

When it is desired to deny access to data from a certain time due to the disappearance of the access right of the data user, it is necessary to delete the data in the auxiliary storage device of the data user. There is a problem in that data access indefinitely cannot be prevented by copying and hiding data.

An object of the present invention is to provide a data delivery method capable of preventing unauthorized access to data and ensuring that the data provider can access the data.

[0015]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a data provider device which stores data stored in a data provider storage device in response to a use request from the data user device. In a data delivery system for delivery to a user device, a pair of key data composed of a public key and a secret key of asymmetric cryptography is generated in a data provider device for data to be delivered. The data is encrypted with the key data and delivered to the data
It is stored in the user side storage device, and in response to a use request of the stored data, the other key data is transferred to the data user side device as a decryption key and decrypted. Is encrypted with one key data of a pair of key data newly generated in the data provider side device.
The procedure of restoring data in the data user side storage device is repeated every time a use request is issued from the same data user side device,
The data stored in the data provider storage device is delivered to the data user device in response to a use request.

Then, the history of the usage request from the same data user side device is monitored by the data provider side device, and the use of the data stored in the data user side storage device is regulated according to the history. It is characterized by having done.

Further, the present invention is characterized in that the pair of key data is composed of a public key and a secret key of asymmetric cryptography.

[0018]

According to the present invention, a pair of key data composed of a public key and a secret key is generated in the data provider device for data to be delivered. For example, key data A1,
Generate A2. Then, the data to be delivered is encrypted with the one key data A1 and delivered to the data user side device.
And store it in the data user side storage device.

When there is a use request for the stored data, the other key data A2 is transferred to the data user side device as a decryption key, and is decrypted with this key data A2 and used. At this time, the data provider encrypts the decrypted data with one key data B1 of a pair of key data B1 and B2 newly generated by the data provider side, and uses the data.
Re-store in the user's storage device. Repeat this procedure every time the use request from the same data user side apparatus is issued, de
The data stored in the data provider side storage device is delivered to the data user side device in response to a use request.

That is, the data user side device is given a new decryption key every time data is accessed, and accesses the data with the new decryption key. And, once accessed data, it is encrypted with a new key data data users
It is stored again in the side storage device. Therefore, the data user side device cannot access data except when a new use request is made and a new decryption key is reissued. That is, the data cannot be accessed unless the delivery request is sent to the data provider side. Therefore, unauthorized access to data can be prevented, and the data provider can reliably grasp that data has been accessed.

Then, the history of the use request from the same data user side device is monitored in the data provider side device. This makes it possible to regulate the use of data stored in the data provider storage device according to the history.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the illustrated embodiments.

(Embodiment 1) First, an embodiment using asymmetric cryptography will be described.

FIG. 1 is a block diagram showing the overall configuration of the data provider and user systems.

In FIG. 1, reference numerals 101 and 102 denote computer systems having a function of communicating via a network 103, 101 denotes a data user's computer system, and 102 denotes a data provider's computer system.

Reference numerals 104 to 106 denote auxiliary storage devices;
Are terminal devices for operating the computer system 101;
Reference numeral 08 denotes a terminal device for outputting data on the user side. The output device 108 is configured by a device such as a printing device or a display device that does not have a data storage function or a data transfer function.

Reference numeral 109 denotes a key generation unit that generates data of an encryption key and a decryption key in accordance with the algorithm of the asymmetric encryption method.
Reference numeral 0 denotes a key distribution unit that transfers key data via the network 103.

Reference numeral 111 denotes a request history processing unit which manages the number of times and date / time of decryption key transfer requests transmitted to access data by a data user, and 112 denotes a key generation unit 1
09: an encryption processing unit for encrypting data to be delivered in accordance with the key data generated in step 09; a key request transmission unit 113 for requesting a decryption key necessary for accessing the encrypted data to the data provider via the network 103 It is.

Reference numeral 114 denotes a decryption processing unit for decrypting the encrypted data using the decryption key. Reference numeral 115 denotes an encryption processing unit for encrypting the decrypted data again using the encryption key and storing it in the auxiliary storage device 104. .

FIG. 2 shows the configuration of a key data storage table 200 in which the computer system 102 on the data provider side stores data related to a key pair. Created for each user.

The key data storage table 200 for each user stores an area for storing a user ID 201 for identifying the user and a data ID 202 for identifying each of a plurality of data used by the user. An area for storing a key pair 203 composed of an encryption key and a decryption key, and a storage area for a flag 204 indicating that the key pair 203 has already been transferred to the data user side.

Here, of the key pair 203, A1, B
1, C1,... Are encryption keys, A2, B2, C2,.
Is a decryption key.

FIG. 3 shows the structure of the key information transferred to the data user side.
D301, decryption key data 302, and encryption key data 303.

FIG. 4 is a flowchart showing the flow of the processing of this system. Hereinafter, the operation of this embodiment will be described with reference to this flowchart.

First, the data user registers a user ID 201 that can be uniquely identified by the data provider in the data provider side computer system 102 before receiving the data provision (delivery) from the data provider side. This user ID
201 is stored in the key data storage table 200 of FIG. In addition, when different data is provided, a data ID 202 for identifying the corresponding data is registered in the data provider side computing system 102 each time. This data I
D202 is stored in the key data storage table 200 of FIG.

On the other hand, the data provider side computing system 102 determines a period during which the user is allowed to access the corresponding data, and stores it in the auxiliary storage device 106 by the request history processing unit 11.

Thereafter, the data provider side computing system 10
2, the key generation unit 109 generates a pair of asymmetric key pairs 203 in accordance with the algorithm of the asymmetric encryption method before transferring the data to be delivered (step 401). For example, A
A pair of key data of the key pair 203 such as 1 and A2 is generated. This key pair 203 corresponds to the key data storage table 2 in FIG.
00 is stored.

Next, the data to be delivered is encrypted using one of the key pairs 203 as an encryption key (step 402). For example, the key data A1 is encrypted as an encryption key. And
Flag 204 indicating that key data A1 has been used
Is set.

Next, the encrypted data to be distributed is transferred to the user's computer system 101 via the network 103 together with the data ID (step 403).

Upon receiving the encrypted data, the computer system 101 on the user side stores the encrypted data in the auxiliary storage device 1.
04 (step 404).

In this state, the data access request from the data user from the terminal device 107 and the output device 10
8 (step 405),
The computer system 101 transfers the ID of the data to be accessed as the decryption key transfer request from the key request transmission unit 113 to the computer system 102 on the data provider side (step 406).

The decryption key transfer request is received by the request history processing unit 111 and stored in the auxiliary storage device 106 as history information.

Here, if the date and time of receiving the decryption key transfer request exceeds the period set and registered in advance, it is a use request from a person whose access right has expired. At this point, the process ends (step 4).
07).

In this case, the key data A1 and A2 are both used and the flag 204 is set.

However, if it does not exceed, the key generation unit 109 newly generates another pair key data B1, B2 (step 408). This new key data B
1 and B2 are stored in the key data storage table 200.

Next, the data ID and the key data A2 and B1 are assembled into the data structure shown in FIG. 3, respectively, and transferred to the user computer system 101 by the key distribution unit 110 (step 409). Then, the flag 204 indicating that the key data A2 and B1 have been used is set.

Computer system 101 on the data user side
Decrypts the encrypted data stored in the auxiliary storage device 104 with the received key data A2, and outputs the decrypted data from the output device 108 (step 410).

When the output to the output device 108 is completed, the decrypted data is encrypted using the key data B1 and stored again in the auxiliary storage device 104 (step 41).
1).

Thereafter, the above processing is repeated every time a decryption key transfer request is issued from the same user (step 4).
12-415).

[0050] Day Thus, on the data in shipping, to generate a pair of key data in the computer system 102 of the data provider side, encrypted with one of its key data
Data to the computer system 101 of the user
It is stored in the user-side auxiliary storage device 104, and in response to a use request of the stored data, the other key data is transferred to the data user's computer system 101 as a decryption key and decrypted. Additionally, data encrypted with one key data of a pair of key data newly generated in the computer system 102 of the data provider side with respect to the decoded data
By repeating the procedure of restoring data in the data user- side auxiliary storage device 104 every time a use request is issued from the same data user, the data user's computer system 101 issues a new use request and Except when the decryption key is reissued, the data in the data user side auxiliary storage device 104 cannot be accessed.

That is, the data cannot be accessed unless the delivery request is sent to the computer system 102 of the data provider on a regular basis. Therefore, unauthorized access to data can be prevented, and the fact that the data has been accessed can be reliably grasped by the computer system 102 of the data provider.

Also, the history of use requests from the same data user is monitored by the request history processing unit 111 , and when the usable period is over, the use of the data is prohibited, so that access without the use right is prohibited. Can be banned.

(Embodiment 2) Next, an embodiment for limiting the number of times data is accessed will be described.

FIG. 5 shows a key data storage table 50 in which the computer system 102 on the data provider side stores key data.
0, the key data storage table 50
0 is created in the auxiliary storage device 105 for each user.

The key data storage table 500 of each user stores an area for storing a user ID 501 for identifying the user and a data ID 502 for identifying each of a plurality of data used by the user. An area for storing the decryption key data 503 and a storage area for a flag 504 indicating that the decryption key data 503 has already been transferred to the data user side.

FIG. 6 shows the configuration of a key data storage table 600 for storing information related to a key possessed by the computer system 101 on the data user side. Data I
Created for each D.

An area in the table 600 for storing the data ID 601 to which the key data is applied, an area for storing the encryption key data 602, and an area for storing the encryption key data 602.
6 indicating that has already been used for encryption processing
03 storage areas.

FIG. 7 shows the structure of information transferred from the computer system 102 on the data provider side to the computer system 101 on the user side.
D701 and decryption key data 702.

FIG. 8 is a flowchart showing the flow of the processing of this embodiment. Hereinafter, according to this flowchart,
The operation of this embodiment will be described.

First, the data user registers a user ID 501 that can be uniquely identified by the data provider in the data provider side computer system 102 before receiving the provision (delivery) of the data from the data provider side. This user ID
201 is stored in the key data storage table 500 of FIG. In addition, when different data is provided, a data ID 502 for identifying the corresponding data is registered in the data provider-side computing system 102 each time. This data I
D502 is stored in the key data storage table 500 of FIG.

On the other hand, the data provider-side computing system 102 determines the number of times the user is allowed to access the corresponding data, and stores it in the auxiliary storage device 106 by the request history processing unit 11.

Thereafter, the data provider side computing system 10
2, the key generation unit 109 generates the same number of asymmetric key pairs as the number of times according to the algorithm of the asymmetric cryptography prior to the transfer of the delivery target data (step 801).
For example, key data of a key pair such as A1, A2, B1, and B2 is generated.

A2, B2, and C2 of the key pair are stored as decryption key data in the key data storage table 500 of FIG. A1, B1, and C1 are temporarily stored in the auxiliary storage device 105 as an encryption key data list having the same configuration as that of FIG.

Next, the data to be distributed is encrypted using the encryption key data A1 (step 802). And
In the key data storage table 500 of FIG.
1 sets a flag 504 indicating that it has been used.

Next, the encrypted data to be distributed is transferred to the user computer system 101 via the network 103 together with the encryption key data list temporarily stored in the auxiliary storage device 105 (step 803). .

Upon receiving the encrypted data, the computer system 101 on the user side stores the encrypted data in the auxiliary storage device 1.
04 (step 804). The encryption key data list is also stored in the key data storage table 600 of FIG. 6 created in the auxiliary storage device 104.

In this state, the data access request from the data user from the terminal device 107 and the output device 10
8 is input (step 805),
The computer system 101 transfers the ID of the data to be accessed as the decryption key transfer request from the key request transmission unit 113 to the computer system 102 on the data provider side (step 806).

The decryption key transfer request is received by the request history processing section 111 and stored in the auxiliary storage device 106 as history information.

Here, if there is no unused decryption key for the decryption key group created and registered in advance, it is a use request from a person whose access right has expired. The process ends (step 807).

However, if there is an unused decryption key, the data ID and the key data A2 are assembled into the data structure shown in FIG.
(Step 808). And key data A2
Sets a flag 504 indicating that it has been used.

Computer system 101 on the data user side
Decrypts the encrypted data stored in the auxiliary storage device 104 with the received key data A2, and outputs the decrypted data from the output device 108 (step 809).

When the output to the output device 108 is completed, the decrypted data is encrypted using the key data B1 and stored again in the auxiliary storage device 104 (step 81).
0).

Thereafter, the above processing is repeated every time a decryption key transfer request is issued from the same user (step 8).
11-814).

Then, if there is no longer any unused decryption key among the decryption keys registered for each user in advance, the process ends.

Therefore, in this embodiment, access is permitted the same number of times as the decryption key registered for each user in advance, but access beyond that is prohibited.

In the above embodiments, the encrypted data to be distributed is stored in the auxiliary storage device 104 of the user, but is stored in the auxiliary storage device that can be accessed by both the provider and the user. The configuration may be as follows.

Although data is distributed via the network 103, it goes without saying that the present invention can be applied to a configuration that does not use a network.

[0078]

In the present invention as described above, according to the present invention, on the data in shipping, the data provider side apparatus generates a pair of key data, encrypted with one of its key data de
The data is delivered to the data user side device and stored in the data user side storage device, and in response to a use request of the stored data, the other key data is transferred to the data user side device as a decryption key. The data provider side encrypts the decrypted data with one key data of a pair of key data newly generated in the data provider side apparatus, and encrypts the decrypted data in the data user side storage apparatus. The procedure of restoring is repeated every time a use request is issued from the same data user side device, and the data stored in the data provider side storage device is returned to the data user side device according to the use request. , The data user side device cannot access the data except when a new use request is made and a new decryption key is reissued. That is, the data cannot be accessed unless the delivery request is sent to the data provider side. Therefore, unauthorized access to data can be prevented, and the data provider can reliably grasp that data has been accessed.

In addition, since the history of the usage request from the same data user side device is monitored in the data provider side device, it is stored in the data user side storage device according to the history. Data usage can be regulated.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a key data management table created in a data provider system in the first embodiment.

FIG. 3 is a configuration diagram of key data transferred to a data user in the first embodiment.

FIG. 4 is a flowchart illustrating a flow of a process according to the first embodiment.

FIG. 5 is a configuration diagram of a key data management table created in a data provider system in a second embodiment.

6 is a block diagram of a key data management tables created user system data utilization in the second embodiment.

FIG. 7 is a configuration diagram of key data transferred to a data user in a second embodiment.

FIG. 8 is a flowchart illustrating a flow of a process according to the second embodiment.

[Explanation of symbols]

101, 102: Computer system, 104, 105, 1
06 ... Auxiliary storage device, 107 ... Terminal device, 108 ... Output device, 109 ... Key generation unit, 110 ... Key distribution unit, 111 ...
Request history processing unit, 112 ... encryption processing unit, 113
... Key request transmission unit, 114... Decryption processing unit, 115
... Encryption processing unit.

Claims (3)

(57) [Claims] A data delivery system for delivering data stored in a data provider side storage device by a data provider side device to a data user side device in response to a use request from the data user side device. in, on the data in shipping, a pair of key data is composed of a public key and a private key of an asymmetric cryptography generates the data provider side apparatus, encrypted with one of its key data Day
The data is delivered to the data user side device and stored in the data user side storage device. In response to the use request of the stored data, the other key data is transferred to the data user side device as a decryption key. The procedure for encrypting the decrypted data with one key data of a pair of key data newly generated in the data provider device and re-storing the decrypted data in the data user storage device is the same. Data delivery characterized by repeating each time a use request from the data user side device is issued, and delivering the data stored in the data provider side storage device to the data user side device according to the use request. Method. 2. A monitor in the data provider side apparatus a history of use request from the same data user side apparatus, to restrict the use of the data stored in the data user storage device according to the history The data delivery method according to claim 1, wherein: 3. A storage device which is commonly accessible by a data provider device and a data user device, wherein the data provider device uses data stored in the storage device from the data user device. In a data distribution system for storing data in a storage device so that it can be used by a data user side device in response to a request, the data provider side device comprises a public key and a secret key of asymmetric cryptography in the data provider side. A pair of key data is generated, encrypted with one of the key data, and stored in the storage device. In response to a request for using the stored data, the other key data is used as a decryption key. The data is transferred to the user side device to be decrypted, and the decrypted data is encrypted with one key data of a pair of key data newly generated in the data provider side device, and the storage device is decrypted. The procedure is repeated each time a use request from the same data user side device is issued, and the data stored in the storage device is delivered to the data user side device according to the use request. Data delivery method to be used.