JP2005208841A - Communication system, portable terminal and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system for enabling a portable terminal to safely use secret information. <P>SOLUTION: A management server 1 generates a plurality of distributed data by arithmetic processing by a secret distribution method for the secret information of a user, and integrates a portion of distributed data into an application, and transmits it. Also, the management server 1 transmits the distributed data other than the distributed data integrated into the application and distribution key vector information or the like to a portable terminal 2. The portable terminal 2 receives and stores the application into which the distributed data are integrated. Also, the portable terminal 2 receives the distributed data other than the distributed data integrated into the application and the distribution key vector information or the like from the management server 1, and associates them with the application for storage. At the time of executing the application, the distributed data are selected at random from the distributed data set as the program and relevant data of the application, and the secret information is restored from the selected distributed data and the distribution key vector information, and transmitted to the service providing terminal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a communication system for safely protecting transmission data in a system for transmitting important data such as personal information to a portable terminal.

In recent years, mobile terminals such as mobile phones and PDAs have personalized applications by setting data such as credit card information and personal information for downloaded applications, and using the personalized applications, A system that can perform data communication with a service providing terminal that provides various services to a user and receive provision of individual services has been realized.
In a system that sends and receives important data (secret information) such as credit card information and personal information between computers, security measures are necessary to prevent unauthorized acquisition of personal information etc. by a third party. Various mechanisms using techniques such as encryption and encryption have been devised.

For example, there is a data protection method in which different key data is generated for each storage unit based on one password, and the data of each storage unit is encrypted using the generated key data (see Patent Document 1).
Japanese Patent Laid-Open No. 11-272561 (4th, 5th page, FIG. 1)

  For example, in the case of a system that frequently performs cryptographic operations such as DES (Data Encryption Standard) and triple DES in order to send and receive data safely, an ordinary mobile terminal that does not have a coprocessor dedicated to cryptographic operations However, it took a long time for the arithmetic processing and was not practical.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a communication system and the like that can safely use a user's confidential information even in a relatively simple terminal such as a portable terminal. .

In order to achieve the above object, a communication system according to the first aspect of the present invention provides:
Secret information storage means for storing the secret information of each user;
Means for reading out secret information of the designated user from the secret information storage means in response to a request from the portable terminal;
Means for generating a plurality of distributed data by performing arithmetic processing by a secret sharing method on the read secret information;
Means for incorporating the generated distributed data into an application program and transmitting it to the mobile terminal of the user;
A server comprising: transmission means for transmitting distributed data other than the distributed data incorporated in the application program; and distributed key vector information used for generating the distributed data to the mobile terminal of the user;
Means for transmitting a request including a user designation to the server and receiving a program of an application in which the distributed data is embedded;
Storage means for storing the program of the received application;
The distributed data other than the distributed data incorporated in the received application program and the distributed key vector information used to generate the distributed data are received from the server and associated with the received application and stored. Receiving means for storing in the means;
Means for randomly selecting distributed data from the distributed data set in the program of the application and data related to the application when executing the application stored in the storage means;
Restoring means for restoring secret information using the selected shared data and the distributed key vector information;
Means for transmitting the restored secret information to a service providing terminal, and a portable terminal comprising:
A service providing terminal that authenticates the portable terminal using the secret information received from the portable terminal, and performs processing for providing a service based on the authentication result;
It is characterized by providing.

  According to such a configuration, secret information can be safely supplied to the mobile terminal without performing enormous cryptographic computation processing. Further, since the secret information is restored and used when the application is executed, the secret information can be protected without depending on tamper-resistant hardware or the like. Also, distributed data for restoring secret information is divided and supplied at a plurality of timings, and a plurality of distributed data storage locations are provided in the portable terminal, so that the security of the system can be improved.

The transmission means of the server may transmit data obtained by encrypting the distributed key vector information with an encryption key and data of the encryption key encrypted with a password base key generated based on a user password. Often,
When the server receives a request to change a user's password from the mobile terminal, the server encrypts the distributed key vector information related to the user with a password-based key generated based on the changed password and transmits the encrypted information to the mobile terminal. There may be further provided means.

The receiving means of the mobile terminal may receive distributed key vector information encrypted with an encryption key and encryption key data encrypted with a password base key based on a user password,
The portable terminal is
Means for accepting a password and generating a password-based key based on the entered password;
Means for obtaining distributed key vector information by decrypting the encrypted encryption key with the password-based key and decrypting the encrypted distributed key vector information with the decrypted encryption key;
Counting means for counting the number of times of decryption of the same distributed key vector information;
Means for transmitting the counted number of times of decoding to the service providing terminal,
The service providing terminal may include means for updating the distributed key vector information stored in the mobile terminal when the received number of decryption times exceeds a certain value.

The transmission means of the server may transmit a part of the distributed data other than the distributed data incorporated in the application program to the mobile terminal,
The server
Distributed data other than the distributed data incorporated in the application program, the distributed data holding means for storing the distributed data other than the distributed data transmitted by the transmitting means;
In response to a request from the portable terminal, the distributed data stored by the distributed data holding unit may be transmitted to the portable terminal,
The mobile terminal may request the shared data held by the server from the server when restoring the secret information.

A portable terminal according to the second aspect of the present invention is
Means for transmitting a request including a user designation to a server storing user secret information and receiving a program of an application in which distributed data generated from the user secret information is embedded;
Storage means for storing the program of the received application;
Of the distributed data generated by the server, distributed data other than the distributed data incorporated in the received application program and the distributed key vector information used to generate the distributed data are received from the server. Receiving means for storing in the storage means in association with the received application;
Means for randomly selecting distributed data from the distributed data set in the program of the application and data related to the application when executing the application stored in the storage means;
Means for restoring secret information using the selected shared data and the distributed key vector information;
Means for transmitting the restored secret information to a service providing terminal for receiving the service;
It is characterized by providing.

A program according to the third aspect of the present invention is:
On the computer,
Transmitting a request including a user designation to a server storing user secret information, and receiving a program of an application in which distributed data generated from the user secret information is embedded;
Storing the received application program in a predetermined storage area;
Of the distributed data generated by the server, distributed data other than the distributed data incorporated in the received application program and the distributed key vector information used to generate the distributed data are received from the server. Storing in the storage area in association with the received application,
A step of randomly selecting distributed data from the distributed data set in the program of the application and the data related to the application when the application stored in the storage area is executed;
Restoring secret information using the selected shared data and the distributed key vector information;
Transmitting the restored secret information to a service providing terminal to receive service provision;
Is executed.

  According to the present invention, the secret information of the user can be safely used even in a relatively simple terminal such as a portable terminal.

  Hereinafter, according to the embodiment of the present invention, the user's mobile terminal restores the secret information such as the user's personal information and credit information based on the information received from the management server, and the restored secret information is stored in the service providing terminal. A communication system that allows a user to receive various services by transmission will be described with reference to the drawings.

  A configuration example of a communication system according to an embodiment of the present invention is shown in FIG. This communication system includes a management server 1, a mobile terminal 2, and a service providing terminal 3. The management server 1 and the mobile terminal 2 are connected via the network 10. In addition, the mobile terminal 2 and the service providing terminal 3 include various local I / Fs such as a Bluetooth interface (I / F), an infrared I / F, a contact IC card I / F, and a non-contact IC card I / F. Connected by F.

A configuration example of the management server 1 is shown in FIG. The management server 1 includes a computer that includes a control unit 11, a storage unit 12, and a communication control unit 13.
The control unit 11 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, reads an operation program stored in the storage unit 12 in advance, and responds to a download request. An application supply process for supplying an application program or the like to the mobile terminal 2, a distributed data supply process for supplying distributed data or the like to the mobile terminal 2 is executed in response to the distributed data request.

In the application supply process, when receiving a download request including, for example, a user ID, an application name, and the like from the portable terminal 2, the control unit 11 searches and reads out the confidential information of the requesting user from the user DB in the storage unit 12. For the secret information, a plurality of shared data is generated (calculated) according to the secret sharing method.
Specifically, the control unit 11 generates a plurality of linearly independent secret keys using, for example, arbitrarily generated random numbers, and generates a distributed key vector group in which the secret keys are arranged as a column. Note that this distributed key vector group may be generated in advance. Next, the control unit 11 extracts n bytes (n is the length of the secret key) from the user's secret information (hexadecimal original data), multiplies the distributed key vector group and the vector, and sets the result as a column. In the arranged data group, data collected for each row is generated as distributed data. For example, when generating shared data for the user's secret information as shown in FIG. 3A, a key vector group as shown in FIG. 3C is generated from the key vector as shown in FIG. 3B. Then, as shown in FIG. 3 (d), the secret information is taken out by 2 bytes, the distributed key vector group is multiplied by the vector, and the data is recollected for each row for the data group in which the result is arranged as a column. Thus, each distributed data is generated.

Then, the control unit 11 stores the generated distributed data and the like in the storage unit 12 in association with data such as a user ID and an application name of the requested application. In this distributed data generation process, for example, `` Shamir, A: How to Share a Share a Secret, Comm. Assoc. Comput. March., Vol. 22, no. 11, pp. 612-613 (Nov. 1979 The secret sharing method using Shamir's polynomial shown in “)” is used.
Further, the control unit 11 downloads at least one shared data among the plurality of generated shared data and data of a matrix table (restoration table) for polynomial operation used when restoring the secret information. Embed in the program data of the application. The number of distributed data embedded in the application may be a predetermined number or may be determined randomly. Further, the restoration table is an addition table and an integration table that are referred to when performing a matrix operation. For example, each table takes a number of 0 to 15 in the vertical and horizontal directions, and the addition table is in the vertical and horizontal directions. The values obtained by adding the horizontal values are set, and the integration table is set by adding the values obtained by integrating the vertical and horizontal values. Since addition processing and multiplication processing of polynomial operations take a long processing time, the processing time can be reduced by using such a table. In the distributed data generation process, the control unit 11 may perform a matrix operation using the restoration table.
Then, the control unit 11 transmits the application program and the application name data in which the distributed data and the restoration table are embedded to the requesting mobile terminal 2.

  In the distributed data supply process, when the control unit 11 receives a distributed data request including, for example, a user ID and an application name from the mobile terminal 2, the control unit 11 reads out and reads out the password of the requesting user from the user DB of the storage unit 12. Generate a password-based key based on the password. The password base key is generated, for example, by performing a hash operation on data obtained by combining a password and a parameter (key generation parameter). Then, the control unit 11 reads out from the storage unit 12 the shared data previously generated for the requesting user and the data of the distributed key vector group used to generate the distributed data, and uses a predetermined encryption key (root key). Thus, the distributed key vector group is encrypted. Among the read distributed data, a plurality of distributed data other than the distributed data previously embedded in the application, the encrypted distributed key vector group, the data obtained by encrypting the root key with the user's password base key, the root Data such as a key message authentication code (MAC: message authentication code) and a key generation parameter is transmitted to the mobile terminal 2 and set in data used by the application in the mobile terminal 2. The root key may be generated every time the distributed key vector group is encrypted, or a predetermined encryption key may be used.

The storage unit 12 is composed of, for example, a hard disk device or the like, and stores an operation program to be executed by the control unit 11 and various data necessary for processing. In addition, the storage unit 12 includes a user DB or the like in which each user's secret information (for example, credit information, authentication key, personal information, etc.) and data such as a password are associated with the user ID and registered for each user. .
The communication control unit 13 performs data communication with the mobile terminal 2 via the network 10. The network 10 includes, for example, the Internet, a dedicated line, a public line network, a mobile communication network, and the like.

A configuration example of the mobile terminal 2 is shown in FIG. 4, and a configuration example of the service providing terminal 3 is shown in FIG. 5. Moreover, the functional block diagram of the portable terminal 2 and the service provision terminal 3 is shown in FIG.
The mobile terminal 2 includes, for example, a computer including a CPU 21, a memory 22, an input unit 23, a display unit 24, a communication unit 25, and a local I / F 26, and includes a mobile phone, a PDA (Personal Digital Assistance). ) Etc.

  The CPU 21 logically implements a download request unit 211, a distributed data request unit 212, a verification unit 213, an information restoration unit 214, an authentication unit 215, a service execution unit 216, and the like by executing a program stored in the memory 22. To do.

  The download request unit 211 transmits an application download request to the management server 1 to download the application. Specifically, data such as a user ID and an application name is transmitted together with a download request, and is used to restore at least one of the plurality of distributed data generated from the user's secret information and the secret data. The program data and application name of the application in which the restoration table is embedded are received and stored in the memory 22.

  The distributed data request unit 212 transmits a distributed data request to the management server 1 in order to acquire distributed data necessary for personalization of the downloaded application. Specifically, data such as a user ID and an application name is transmitted to the management server 1 together with the distributed data request, and a plurality of distributed data other than the distributed data embedded in the downloaded application, an encrypted distributed key vector group, Data such as the encrypted root key, MAC, and key generation parameters are received and stored in the data area used by the application stored in the memory 22 to personalize the application.

  The verification unit 213 verifies the MAC (message authentication code) stored in the memory 22 when the application program is activated. Specifically, the password input by the user is accepted, a password base key is generated from the input password, and the encrypted password stored in the data area used by the application is generated using the generated password base key. Decrypt the root key. Note that the password base key is generated by performing a hash operation on data that is a combination of the input password and the key generation parameters stored in the data area used by the application, for example. Then, a MAC is generated for the decrypted root key, and verified with an authentication code (MAC) stored in a data area used by the application. Note that a method for generating a MAC (message authentication code) is arbitrary, and for example, it may be generated by performing a hash operation on the root key. If the collation data match, it is determined that the authentication code stored in the memory 22 is correct, and the local I / F 26 is controlled to start communication with the service providing terminal 3.

  The information restoration unit 214 restores the secret information from the distributed data set in the activated application and data used by the application. In this secret information restoration process, a random number is generated, and a plurality of distributed data to be used for restoring the secret information is determined using the generated random number. For example, when random numbers 1, 5, 8,... Are generated, the distributed data W1, W2,..., Wn to W1, W5, W8. The random number generation method is arbitrary, and it may be generated using a random number generation function expression stored in the memory 22, or the random number generation received from the management server 1 and stored in the memory 22 A value calculated by using a one-way function or the like, which is a combination of time parameters acquired from an internal parameter and an internal timer, may be used as a random number. Next, the information restoration unit 214 decrypts the encrypted distributed key vector group stored in the memory 22 using the root key decrypted by the verification unit 213. Then, from the distributed data set in the application and the data used in the application, a plurality of distributed data previously selected as distributed data to be used for restoration and a restoration table are acquired, and the inverse of the distributed vector group is obtained. The matrix is calculated, and the secret information is restored by performing a matrix operation using the selected shared data, the restoration table, and the inverse matrix of the distributed vector group. The restored secret information includes, for example, data such as user credit information and an authentication key.

As for the secret sharing scheme used in the present invention, the case of the extension field GF (2 ^m ) is shown as an example. When xi is a distributed key and r is an arbitrary variable, The secret information S can be restored from k pieces of distributed information among the n pieces of distributed information f (xi).

(Equation 1)

For example, when n = 3 and k = 2, the distributed information is as follows.
f (x1) = S + r1 · x1 + r2 · x1
f (x2) = S + r1 · x2 + r2 · x2
f (x3) = S + r1 * x3 + r2 * x3
In this case, S can be restored by solving simultaneous equations from two of the three simultaneous equations of two variables including the shared information and the key vector. The simultaneous equations can also be solved by matrix calculation. When the key vector is two-dimensional and the distributed data is two elements each, it can be calculated by matrix calculation as shown in (Equation 2).

(Equation 2)

More specifically, for example, when the first and third shared data are selected as the shared data to be used for restoration from among a plurality of shared data, the information restoring unit 214 in FIG. As shown, a corresponding key vector is extracted from the distributed key vector group A, and an inverse matrix B ⁻¹ of the distributed key vector group B composed of the extracted vectors is generated. Then, as shown in FIG. 7B, integration of the generated inverse matrix B ⁻¹ and a vector combining the selected distributed data is performed. Note that a restoration table is used for addition and integration in the vector calculation. Then, the information restoration unit 214 restores the secret information by connecting the elements of the calculation result vector.

The authentication unit 215 performs authentication processing with the service providing terminal 3. Specifically, for example, the local I / F 26 transmits a communication request to the service providing terminal 3 in response to the activation of the application, and the communication with the service providing terminal 3 is established, and then received from the service providing terminal 3. The random number is encrypted with the authentication key included in the restored secret information and transmitted to the service providing terminal 3. When authentication by the portable terminal 4 is completed, the service can be used thereafter.
For example, after receiving an OK signal for the transmitted authentication data from the service providing terminal 3, the authentication unit 215 generates a random number on the mobile terminal 2 side and transmits it to the service providing terminal 3. Mutual authentication may be performed by receiving a code or the like and confirming whether or not the transmitted random number is included in the data obtained by decrypting the received authentication code with the authentication key.

  After the authentication processing by the authentication unit 215 is correctly completed, the service execution unit 216 performs processing for receiving and receiving service provision by transmitting and receiving secret information and various data related to other services to and from the service providing terminal 3. . The content of the service is arbitrary. For example, it may be a payment service such as credit payment or electronic money payment in a vending machine or a POS terminal, or may be an account processing service such as withdrawal, deposit, or account transfer in an ATM terminal.

  The memory 22 includes a ROM, a RAM, and the like, and stores an operation program to be executed by the CPU 21, various data necessary for processing, a user ID, and the like. Further, for example, as shown in FIG. 8, the memory 22 stores program data of an application in which at least one distributed data and a restoration table are embedded, and data related to the application (data used in the application). It is memorized every time. For example, distributed data, an encrypted distributed key vector group, an encrypted root key, a MAC, a key generation parameter, and the like are set in the data used in the application.

The input unit 23 is composed of an input device including a keyboard and a pointing device, for example, and notifies the CPU 21 of input data.
The display unit 24 includes a liquid crystal display and the like, and performs various screen displays.
The communication unit 25 performs data communication with the management server 1 via the network 10.
The local I / F 26 is an I / F that performs short-range data communication with the service providing terminal 3 in accordance with a predetermined communication method, and includes, for example, a CPU, a ROM, a RAM, a receiver, a transmitter, and the like. Note that the type of communication method of the local I / F 26 is arbitrary. For example, a Bluetooth interface (I / F), an infrared I / F, a contact IC card I / F, a non-contact IC card I / F, or the like may be used.

  The service providing terminal 3 includes a computer including a control unit 31, a storage unit 32, an input unit 33, a display unit 34, a communication unit 35, a local I / F 36, and the like.

The control unit 31 logically implements the portable terminal authentication unit 311, the service execution unit 312, and the like by executing the operation program stored in the storage unit 32.
The mobile terminal authentication unit 311 generates a random number after establishing communication with the mobile terminal 2 via the local I / F 36, and transmits the generated random number to the mobile terminal 2 together with a request for authentication data. Then, the authentication data is received from the portable terminal 2, and the validity of the authentication data is checked by checking whether the generated random number is included in the data obtained by decrypting the received authentication data with the authentication key.
When the authentication data is correct, the service execution unit 312 transmits / receives various data related to the service to / from the mobile terminal 2 and performs processing for providing the service.

The storage unit 32 includes a ROM, a RAM, a hard disk device, and the like, and stores an operation program to be executed by the CPU 21, various data necessary for processing, information for checking authentication data (such as an authentication key), and the like. ing.
The input unit 33 is composed of an input device including a keyboard and a pointing device, for example, and notifies the control unit 31 of input data.
The display unit 34 includes a liquid crystal display or the like, and performs various screen displays.
The communication unit 35 performs data communication with the management server 1 via the network 10.

  The local I / F 36 is an I / F that performs short-range data communication with the mobile terminal 2 according to a predetermined communication method, and includes, for example, a CPU, a ROM, a RAM, a receiver, a transmitter, and the like. Note that the type of communication method of the local I / F 36 is arbitrary. For example, a Bluetooth interface (I / F), an infrared I / F, a contact IC card I / F, a non-contact IC card I / F, or the like may be used.

Next, in the communication system according to the embodiment of the present invention, in order for the portable terminal 2 to receive the provision of service, the secret information is restored and transmitted to the service providing terminal 3, and the system operation when receiving authentication is shown in FIG. Will be described with reference to FIG.
First, in response to a predetermined input operation, the mobile terminal 2 starts an application program for receiving service provision (step S1), and accepts an input of a password (step S2). Then, the mobile terminal 2 generates a password base key from the input password (step S3), decrypts the root key encrypted using the password base key (step S4), and verifies the MAC. (Step S5).

  If the verification result is NG (step S5: NO), the mobile terminal 2 performs an error process such as displaying an error message and terminating the process (step S6). If the verification result is OK (step S5: YES), the mobile terminal 2 decrypts the encrypted distributed vector group with the decrypted root key (step S7) and the local I / F 26. A predetermined communication procedure is performed by using the to establish communication with the service providing terminal 3 (step S8).

  On the other hand, the service providing terminal 3 activates a program at a predetermined timing (for example, at the start of business) (step S9), performs a predetermined communication procedure using the local I / F 36, and communicates with the mobile terminal 2. Is established (step S10). Specifically, for example, a wireless signal of a predetermined frequency is transmitted, a response signal from the mobile terminal 2 is received, and communication speed is negotiated to establish communication.

Next, the mobile terminal 2 generates a random number, uses the generated random number to select shared data to be used for restoring the secret information (step S11), and selects the distributed data and the decrypted distributed key vector. Using the group inverse matrix and the restoration table, a calculation process for restoring the secret information is performed (step S12).
On the other hand, after establishing communication, the service providing terminal 3 generates a random number, and transmits the generated random number and an authentication data request to the portable terminal 2 (step S13).
The portable terminal 2 generates authentication data using the random number received from the service providing terminal 3 and the authentication key included in the restored secret information, and transmits it to the service providing terminal 3 (step S14).

  The service providing terminal 3 receives the authentication data from the portable terminal 2, decrypts the received authentication data using the authentication key stored in the storage unit 32, and the previously generated random number is added to the decrypted data. The validity of the authentication data is confirmed by confirming that it is included (step S15). If the verification result of the authentication data is NG, error processing such as sending an error message to the mobile terminal 2 and locking the service providing program is performed (step S16). If the verification result of the authentication data is OK Transmits a notification indicating that the authentication is OK to the mobile terminal 2 and transmits / receives various kinds of data related to secret information and other services to / from the mobile terminal 2 to perform a process for providing the service (step) S17).

  As described above, according to the present invention, secret information can be safely supplied to a mobile terminal without performing enormous cryptographic computation processing. Further, since the secret information is restored and used when the application is executed, the secret information can be protected without depending on tamper-resistant hardware or the like. Also, distributed data for restoring secret information is divided and supplied at a plurality of timings, and a plurality of distributed data storage locations are provided in the portable terminal, so that the security of the system can be improved.

The present invention can be variously modified and applied.
For example, in the process of selecting the shared data used by the portable terminal 2 to restore the secret information, the distributed data in the application programming area is selected using the random number generated by the portable terminal 2, and the random number is received from the service providing terminal 3. And the distributed data in the data related to the application may be selected using the received random number.

  Further, when the user updates the password, for example, the mobile terminal 2 allows the user to input the password before the change, performs authentication for checking the password stored in the memory 22 in advance, and then sends the network 10 to the management server 1. And accepts input of a new password, and transmits the input password, user ID and other data to the management server 1 together with a password change request. In response to this, the management server 1 generates a password base key from the new password, and encrypts each distributed key vector information stored in the storage unit 12 in association with the user ID with the generated password base key. Then, the encrypted data such as the distributed key vector information is transmitted to the portable terminal 2, and the password of the corresponding user is updated in the user DB with the received password. The mobile terminal 2 receives data such as a root key encrypted with a password base key based on a new password and a distributed key vector group encrypted with the root key, and updates and stores the data in a corresponding storage area of the memory 22. . The password changing process may be performed for each application. In this case, data specifying an application such as an application name is transmitted from the portable terminal 2, and the management server 1 is also encrypted and distributed. Information specifying an application is assigned to the key vector group and transmitted to the portable terminal 2. In addition, when the password and the distributed key vector group are common to each application, the application need not be specified. In this case, the mobile terminal 2 uses the received encrypted distributed key vector group for each application. Are updated and stored in the corresponding storage areas.

  In addition, when the number of times of decryption of the same distributed key vector group exceeds a certain number in the mobile terminal 2, the data of the encrypted distributed key vector group stored in the mobile terminal 2 is updated. May be. In this case, for example, the portable terminal 2 stores the number of times of decryption of the same distributed key vector group in the memory 22 and adds 1 to the number of times of decryption each time decryption processing is performed. For example, in communication with the service providing terminal 3, the value of the number of times of decoding stored in the memory 22 is transmitted. When the service providing terminal 3 receives the data of the number of times of decryption from the mobile terminal 2, the service providing terminal 3 determines whether the number of times exceeds the upper limit value set in advance in the storage unit 32. The encrypted distributed key vector group data and the like are transmitted to the portable terminal 2 together with the update request. The portable terminal 2 updates and stores the data of the distributed key vector group received from the service providing terminal 3 in the memory 22. In this case, for example, the service providing terminal 3 transmits information specifying the user (user ID or the like) to the management server 1 together with the update request for the distribution vector group data, and the management server 1 responds accordingly. In response to the update request of the distributed vector group data from 3, the distributed key vector group is encrypted with the new root key, and the encrypted distributed key vector group and the new root key are encrypted with the designated user password. The service providing terminal 3 receives the encrypted distributed key vector group data and the encrypted root key data from the management server 1 and receives the received data. May be transmitted to the portable terminal 2 together with the update request.

  The generated distributed data is also stored in the management server 1, and when the portable terminal 2 restores the secret information, the distributed data held in the management server 1 is acquired by connecting to the management server 1. Then, the secret information may be restored. In this case, for example, the distributed data other than the distributed data incorporated in the application program by the management server 1 is divided into the distributed data to be transmitted to the mobile terminal 2 and the distributed data held by the management server 1. Is transmitted to the portable terminal 2 and the latter distributed data is stored in the storage unit 12 together with the user ID, application name, and the like. And when the portable terminal 2 restores the secret information, it connects to the management server 1 and transmits a distributed data request specifying the user ID, application name, etc., and in response to this, the management server 1 The corresponding distributed data may be read out from 12 and transmitted to the mobile terminal 2.

In addition, the management server 1 may change the restoration table for each user and transmit it to the mobile terminal 2.
Further, the distributed key vector information group may be managed as one key data, and the management server 1 may encrypt each distributed data generated by this key data and transmit it to the portable terminal 2.

  In addition, when an IC chip such as a UIM that is difficult to forge or tamper with data is attached to the mobile terminal 2, secret information such as a key required for authentication or encryption communication between the IC chip and the mobile terminal 2 Also, the management server 1 may generate the distributed data, supply it to the portable terminal 2 and the IC chip, and store them, respectively, and restore the portable terminal 2 or the IC chip when using the secret information. In this case, the IC chip may generate a random number for selecting distributed data to be used for restoration. In addition, when it is determined that unauthorized processing such as falsification has been performed on the distributed data stored on the mobile terminal 2 side, a distributed key vector group, distributed data, or the like is generated in the IC chip, or via the IC chip. You may perform the process which acquires a distributed key vector group, distributed data, etc. from the management server 1, and resets to the portable terminal 2. FIG.

The system of the present invention can be realized using a normal computer system, not a dedicated system. For example, a program for executing the above operation is stored in a computer-readable recording medium (FD, CD-ROM, DVD, etc.) and distributed, and the program is installed in the computer to execute the above processing. The management server 1, the mobile terminal 2, the service providing terminal 3 and the like may be configured. Alternatively, it may be stored in a disk device of a server device on the network 10 such as the Internet and downloaded to a computer, for example.
In addition, when the OS realizes the above functions by sharing the OS or jointly with the OS and the application, etc., only the part other than the OS may be stored and distributed in the medium, or may be downloaded to the computer. Good.

It is a figure which shows the structure of the communication system of embodiment of this invention. It is a figure which shows the structural example of a management server. It is a figure for demonstrating the process which produces | generates distributed data. It is a figure which shows the structural example of a portable terminal. It is a figure which shows the structural example of a service provision terminal. It is a functional block diagram of a portable terminal and a service provision terminal. It is a figure for demonstrating the process which decompress | restores secret information. It is a figure for demonstrating the data memorize | stored in memory of a portable terminal. It is a figure for demonstrating the system operation | movement when a portable terminal restore | restores secret information and transmits to a service provision terminal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Management server 2 Portable terminal 3 Service provision terminal 10 Network 11 Control part 12 Storage part 13 Communication control part 21 CPU
22 Memory 23, 33 Input unit 24, 34 Display unit 25, 35 Communication unit 26, 36 Local I / F
31 control unit 32 storage unit 211 download request unit 212 distributed data request unit 213 verification unit 214 information restoration unit 215 authentication unit 216 service execution unit 311 portable terminal authentication unit 312 service execution unit

Claims (6)

Secret information storage means for storing the secret information of each user;
Means for reading out secret information of the designated user from the secret information storage means in response to a request from the portable terminal;
Means for generating a plurality of distributed data by performing arithmetic processing by a secret sharing method on the read secret information;
Means for incorporating the generated distributed data into an application program and transmitting it to the mobile terminal of the user;
A server comprising: transmission means for transmitting distributed data other than the distributed data incorporated in the application program; and distributed key vector information used for generating the distributed data to the mobile terminal of the user;
Means for transmitting a request including a user designation to the server and receiving a program of an application in which the distributed data is embedded;
Storage means for storing the program of the received application;
The distributed data other than the distributed data incorporated in the received application program and the distributed key vector information used to generate the distributed data are received from the server and associated with the received application and stored. Receiving means for storing in the means;
Means for randomly selecting distributed data from the distributed data set in the program of the application and data related to the application when executing the application stored in the storage means;
Restoring means for restoring secret information using the selected shared data and the distributed key vector information;
Means for transmitting the restored secret information to a service providing terminal, and a portable terminal comprising:
A service providing terminal that authenticates the portable terminal using the secret information received from the portable terminal, and performs processing for providing a service based on the authentication result;
A communication system comprising: The transmission unit of the server transmits data obtained by encrypting the distributed key vector information with an encryption key, and data of the encryption key encrypted with a password base key generated based on a user password,
When the server receives a request to change a user's password from the mobile terminal, the server encrypts the distributed key vector information related to the user with a password-based key generated based on the changed password and transmits the encrypted information to the mobile terminal. Further comprising means for
The communication system according to claim 1. The receiving means of the mobile terminal receives the distributed key vector information encrypted with the encryption key and the encryption key data encrypted with the password base key based on the user password,
The portable terminal is
Means for accepting a password and generating a password-based key based on the entered password;
Means for obtaining distributed key vector information by decrypting the encrypted encryption key with the password-based key and decrypting the encrypted distributed key vector information with the decrypted encryption key;
Counting means for counting the number of times of decryption of the same distributed key vector information;
Means for transmitting the counted number of times of decoding to the service providing terminal,
The service providing terminal includes means for updating the distributed key vector information stored in the mobile terminal when the received number of decryption times exceeds a certain value.
The communication system according to claim 1 or 2. The transmission means of the server transmits a part of distributed data other than the distributed data incorporated in the application program to the mobile terminal,
The server
Distributed data other than the distributed data incorporated in the application program, the distributed data holding means for storing the distributed data other than the distributed data transmitted by the transmitting means;
Means for transmitting the distributed data stored by the distributed data holding means to the portable terminal in response to a request from the portable terminal,
The mobile terminal requests the shared data held by the server from the server when restoring the secret information.
The communication system according to any one of claims 1 to 3. Means for transmitting a request including a user designation to a server storing user secret information and receiving a program of an application in which distributed data generated from the user secret information is embedded;
Storage means for storing the program of the received application;
Of the distributed data generated by the server, distributed data other than the distributed data incorporated in the received application program and the distributed key vector information used to generate the distributed data are received from the server. Receiving means for storing in the storage means in association with the received application;
Means for randomly selecting distributed data from the distributed data set in the program of the application and data related to the application when executing the application stored in the storage means;
Means for restoring secret information using the selected shared data and the distributed key vector information;
Means for transmitting the restored secret information to a service providing terminal for receiving the service;
A portable terminal comprising: On the computer,
Transmitting a request including a user designation to a server storing user secret information, and receiving a program of an application in which distributed data generated from the user secret information is embedded;
Storing the received application program in a predetermined storage area;
Of the distributed data generated by the server, distributed data other than the distributed data incorporated in the received application program and the distributed key vector information used to generate the distributed data are received from the server. Storing in the storage area in association with the received application,
A step of randomly selecting distributed data from the distributed data set in the program of the application and the data related to the application when the application stored in the storage area is executed;
Restoring secret information using the selected shared data and the distributed key vector information;
Transmitting the restored secret information to a service providing terminal to receive service provision;
A program that executes

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