JP2006333164A - Information processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To rationally manage an encryption key for encrypting/decrypting data in a terminal. <P>SOLUTION: An encryption key obtained by being encrypted by an external key A of a user input and an encryption key obtained by being encrypted in accordance with user identification information by a public key of an external key B managed by a key management server 11 are respectively stored in a portable terminal 14 as encryption keys of data automatically generated in the terminal 14. As a method for extracting the encryption keys, a method for decrypting the encryption key by the external key A of the user input is used during offline or when there is no change in the external key A, and the key management server is requested to decrypt the encryption key encrypted by the public key of the external key B to receive the encryption key during online and when there is a change in the external key A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an information processing apparatus including a terminal that can be used in an online state connected to a server via a network or in an offline state disconnected from the network.

  The network has developed and most PC (personal computer) terminals are connected to the network in the organization. However, it is difficult to constantly maintain the network connection with a portable terminal such as a notebook PC taken out of the organization. Therefore, it is necessary to store data in the terminal for offline use. However, since portable portable terminals such as notebook PCs have a risk of theft, it is necessary to encrypt data (particularly confidential information) in the portable terminal in order to prevent data leakage to the outside.

  Regarding encryption of data of such portable terminals that can be carried, an information processing apparatus described in Japanese Patent Application Laid-Open No. 11-272561 encrypts an encryption key with a password and changes the encryption key for each block of data. Thus, the data in the medium is secured.

  In the information processing apparatus described in Japanese Patent Laid-Open No. 10-105470, encryption is performed by adding authentication information to data sent from the server to the client, and authentication is essential for decryption at the client. Concealment is achieved by adopting such a configuration.

JP-A-11-272561 JP-A-10-105470

  However, in the method described in Patent Document 1, it is necessary to set passwords individually for each terminal and medium, and it is difficult to manage passwords on a per-user basis. There is a problem that can not be. Further, the method described in Patent Document 2 has a problem that data cannot be encrypted by the client and cannot be realized by offline use.

SUMMARY OF THE INVENTION An object of the present invention is to provide a convenient information processing apparatus capable of encrypting and holding data in a terminal and decrypting and using the data in both online and offline states.
Specifically, data can be encrypted using a password or the like given by the user at the terminal as a key, and the same password can be used even when different terminals are used. It is an object of the present invention to provide an information processing apparatus capable of decrypting data even when the password is changed by another terminal or when the user loses (forgets) the password.

  The present invention identifies a user by using an external key A encrypted key obtained by encrypting an encryption key of data automatically generated in a terminal with an external key A given by a user such as a password, and an external key B managed by a key management server. The external key B encrypted key encrypted together with the information is stored in the terminal, and means for extracting the encryption key is a means A for decrypting the external key A encrypted key by the external key A; Means B is provided for requesting the management server to decrypt the external key B encrypted key and receiving the encryption key. By using means A when offline or there is no change in the external key A, and using means B when the external key A is changed online, the external key A can be changed and reissued flexibly. This makes it possible to operate smoothly.

Specific features are as follows.
First, the information processing apparatus includes a terminal connected to a network and a server, wherein the terminal encrypts and stores data using an encryption key.
The terminal includes a first means A for storing an external key A encrypted key obtained by encrypting an encryption key using information (external key A) that only the user knows, such as a password given by the user, and a server The second means B for storing the user identification information and the external key B encrypted key using the external key B given by the user, and the terminal when the user loses the external key A A third means for requesting the server to decrypt the external key B encrypted key and obtaining an encryption key returned from the server;
The server includes means for returning the encryption key to the terminal after confirming the validity of the user based on the user identification information decrypted based on the external key B encrypted key from the terminal.
Second, in an information processing terminal that can be connected to a server via a network,
In order to store a key (encryption key) used for data encryption, an external key A is encrypted by encrypting the encryption key using information (external key A) that only the user knows, such as a password given by the user. A first means A for storing as an encrypted key, and a second means for storing an external key B encrypted key by encrypting the user identification information and the encryption key using the external key B given from the server in the network connection state. Means B and, when the user loses the external key A, asks the server to decrypt the external key B encrypted key held in the terminal and decrypts the encrypted key from the server. A third means for acquiring is provided.
Third, in the first feature, when an asymmetric key is used as the external key B, the public key of the external key B is distributed in advance from the server to the terminal to encrypt the user identification information and the encryption key. The processing is performed in the terminal, the private key of the external key B is held in the server, and the decryption request from the terminal is performed via a concealed communication path on the network.
Fourth, in the first feature, when a symmetric key is used as the external key B, the external key B is held in the server, the user identification information and the encryption key are encrypted, and the external key B is already encrypted. The key decryption is performed by requesting the server from the terminal via a concealed communication path on the network.
Fifth, in the first feature, data encryption using information that only the system administrator knows as the external key B, such as a password indicated by the system administrator instead of the server, as the external key B The decryption is performed by the Tostem administrator inputting the external key B to the terminal.
Sixth, in the first feature, the encryption key and the encryption algorithm of the data may be configured to be different depending on a plurality of terminals.
Seventhly, in the first or second feature, when the encryption method using the asymmetric key in the third feature is used, the terminal holds the public key of the external key B inside and encrypts it. By performing all key encryption processing within the terminal, the encryption key can be changed even offline.
Eighth, in the first feature, the external key A encrypted key, the external key B encrypted key, and the encrypted data are managed on a medium or data basis, and an encryption key and a data encryption algorithm that differ depending on the medium or data are provided. The feature is that it can be used.
Ninth, in any of the first to ninth aspects, even when different encryption keys and data encryption algorithms are used depending on the medium or data, the encryption key encryption process is made common by the user. The present invention is characterized in that a medium or data encrypted with a different encryption key and data encryption algorithm can be decrypted with the external key once.

As described above, according to the present invention, since the terminal can perform encryption / decryption using the external key A given by the user, such as a password, data can be stored in both online and offline states. Can be encrypted and decrypted.
Further, when the external key A is changed, the server can request the server to decrypt the external key B encrypted key, so that the external key A is changed by another terminal or the user Even when the password is lost (forgotten) and reissued by the administrator, the data can be decrypted.
Therefore, even when different terminals are used, the same external key A can be used for each user. Therefore, a key of user authentication information such as a password can be used as the external key A for encryption. It becomes possible.
Further, when an asymmetric key is used as the external key B, the terminal side does not need to connect to the server when generating the encryption key, and the key management server side uses the private key of the external key B as the key management server. Never go out.
Similarly, when an asymmetric key is used as the external key B, it is possible to change the encryption key even when it is offline when it is determined that the encryption key may have been lost to the outside.
In addition, since all encryption processing is performed within the terminal and information dependent on the encryption key is stored as a single unit, the encryption algorithm for the encryption key and data can be different depending on the terminal, medium, and data. Even in this case, the external key is common, so the user only has to present the external key once.

The present invention comprises a terminal connected to a network and a server, wherein the terminal encrypts data using an encryption key and stores the encrypted data.
The terminal includes a first means A for storing an external key A encrypted key obtained by encrypting an encryption key using information (external key A) that only the user knows, such as a password given by the user, and a server The second means B for storing the user identification information and the external key B encrypted key using the external key B given by the user, and the terminal when the user loses the external key A A third means for requesting the server to decrypt the external key B encrypted key and obtaining an encryption key returned from the server;
The server comprises means for returning the encryption key to the terminal after confirming the validity of the user by the user identification information decrypted based on the external key B encrypted key from the terminal,
When an asymmetric key is used as the external key B, the process of encrypting the user identification information and the encryption key by distributing the public key of the external key B from the server to the terminal in advance is performed within the terminal. The private key is held in the server, and the decryption request from the terminal is made via a concealed communication path on the network,
When a symmetric key is used as the external key B, the external key B is held in the server, the process of encrypting the user identification information and the encryption key, and the decryption of the external key B encrypted key are concealed on the network. This is done by requesting the server from the terminal via the communication path.
Further, data encryption / decryption using information that only the system administrator knows as the external key B, such as a password indicated by the system administrator in place of the server in the external key B, is performed by the system administrator Can be performed by inputting the external key B to
In addition, when using an encryption method using an asymmetric key, the terminal holds the public key of the external key B inside, and performs all encryption key encryption processing within the terminal, thereby enabling encryption even offline. Make the key changeable.

Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram illustrating the configuration of the information processing apparatus according to the first embodiment of this invention. The information processing apparatus according to the first embodiment includes a key management server 11 that performs processing related to decryption of an encryption key, an authentication server 12 that authenticates a user using user identification information and an external key A, and a first LAN or the like. A portable terminal 14 is connected to these servers via the network 13 (online state) and executes an application. The key management server 11 and the authentication server 12 can be configured as a single server. The portable terminal 14 is further connected to a second network 15 such as the Internet (online state) to be used as the portable terminal 14A, and is also used as the portable terminal 14B in an offline state disconnected from the networks 13 and 15. Is done. Network communication is concealed using SSL.

  FIG. 2 is a block diagram showing internal configurations and information processing functions of the key management server 11, the authentication server 12, and the portable terminal 14.

  The key management server 11 includes a microprocessor 111 that executes external key management processing, a disk memory 112 that holds a pair of the public key 112a and the private key 112b of the external key B, and a communication unit 113. The external key B in the first embodiment is an asymmetric key in which the public key 112a and the secret key 112b are different. The public key 112a is used for encryption, and the secret key 112b is used for decryption. The microprocessor 111 communicates with the portable terminal 14 connected to the network, distributes the public key 112a of the external key B to the portable terminal 14, and receives the information passed from the portable terminal 14 in the external key B. A key decryption function 111 a for decrypting using the secret key 112 b is realized, and a process for managing the secret key 112 b so as not to leave the key management server 11 is executed. The key decryption process flow will be described later with reference to FIG.

  The authentication server 12 includes a microprocessor 121 that executes an authentication process, a disk memory 122 that holds an authentication information database 122 a including user identification information of each user and information on the external key A, and a communication unit 123 that communicates with the portable terminal 14. Is provided. The microprocessor 121 executes processing for realizing an authentication function 121a that compares the authentication information (user identification information and external key A) passed from the portable terminal 14 with the contents of the authentication information database 122a and returns an authentication result. The information of the user's external key A registered in the authentication information database 122a can be changed. When the user loses the external key A, the administrator registers the external key A registered in the authentication information database 122a. A new external key A is reissued by changing the key A information.

  The portable terminal 14 includes a microprocessor 141 that executes an application program 141a, a disk memory 142, a semiconductor memory 143, and a communication means 144. The mobile terminal 14 in the online state stores the public key 142a (= 112a) of the external key B distributed from the key management server 11 and the hash value 142b of the external key A input by the user in the disk memory 142 in the initial state. Hold. The contents of the encryption key depend on the external key B-encrypted key 142c, the external key A-encrypted key 142d, and the encrypted data 142e, and these are stored as a single piece of data. For this reason, the portable terminal 14, the medium, and the data are each provided with this one piece of data, so that different encryption keys or encryption algorithms can be used for the portable terminal 14, the medium, and the data.

  FIG. 3 is a functional block diagram showing a state in the portable terminal 14 when data is edited / encrypted / decrypted. The microprocessor 141 in the portable terminal 14 basically starts the application program 141a and edits data (creates new data or changes existing data) based on an instruction input from the editing input device 145 by the data editing algorithm 141a1. ), The edited data 143a on the memory 143 is encrypted and stored in the disk memory 142 as the encrypted data 142e.

  With reference to FIG. 3, data encryption / decryption processing will be described based on the flowcharts shown in FIGS. 4 to 7, and encryption key change processing will be described based on the flowchart shown in FIG. Since data editing (new data creation or modification of existing data) executed by the data editing algorithm 141a1 is the same as the conventional one, a detailed description thereof will be omitted.

  FIG. 4 is a flowchart of processing when the portable terminal 14 generates an encryption key and encrypts data. In this process, an encryption key is generated after client authentication, and the encryption key is encrypted and stored in the disk memory 142, and the edited data is encrypted using the encryption key and stored in the disk memory 142. Further, it is assumed that the public key 142a (112a) of the external key B is acquired online from the key management server 11 in advance and stored in the disk memory 142.

Step S401
Before generating the encryption key, a client (user) authentication process described later with reference to FIG. 6 is performed.

Step S402
Check the authentication result and branch the process. If the authentication result is a failure, the application program is terminated without generating a key and encrypting data.

Step S403
If the authentication result is successful or changed, the encryption key generation algorithm 141a2 is used to generate a random encryption key based on the internal state of the terminal and hold it in the memory 143 as the encryption key 143b.

Step S404
The encryption key 143b held in the memory 143 is encrypted with the external key A input from the external key input device 146 by the first symmetric encryption algorithm 141a3 and stored in the disk memory 142 as the external key A encrypted key 142d. . The hash value of the external key A at this time is stored in the disk memory 142 as the hash value 142b of the external key A by the one-way hash function algorithm 141a6. The process of storing the hash value 142b of the external key A will be described later in the client authentication process.

Step S405
The asymmetric encryption algorithm 141a4 encrypts the encryption key 143b and the user identification information input from the user identification information input device 147 with the public key 142a of the external key B, and saves it in the disk memory 142 as the external key B encrypted key 142c.

Step S406
After the encryption key 143b generated by the above processing is encrypted and securely stored in the disk memory 142, the data 143a in the memory 143 is encrypted by using the encryption key 143b by the second symmetric encryption algorithm 141a5, and the disk The encrypted data 142e is stored in the memory 142.

  Since the process from the generation of the encryption key 143b in step S403 to the data encryption in step S406 can be executed even in an offline state without connection to the server, the client authentication process (step S401) is executed offline. If so, the encryption key 143b can be generated even in an offline state, and the edit data 143a can be encrypted and stored.

  FIG. 5 is a flowchart of processing when the portable data terminal 14 decrypts the encrypted data 142e. In this process, when there is no change in the external key A, the encrypted encryption key inside the terminal is decrypted and used, and when there is a change, the key management server 11 is inquired to obtain the encryption key.

Step S501
Before the decryption, the client authentication process shown in FIG. 6 is performed. A specific example of this client authentication process will be described later.

Step S502
Check the authentication result and branch the process. If the authentication fails, the application program is terminated without performing decryption / encryption.

Step S503
If the authentication is successful, the first symmetric encryption algorithm 141a3 decrypts the external key A encrypted key 142d stored in the disk memory 142 based on the external key A and takes it out as the encryption key 143b on the memory 143. .

Step S504
If the authentication information is changed in the check in step S502, the external key A encrypted key 142d stored in the disk memory 142 cannot be decrypted with the external key A given by the user. The encryption key acquisition process shown in FIG. A specific example of the encryption key acquisition process will be described later.

Step S505
The process branches after checking the result of the encryption key acquisition process. If the encryption key cannot be acquired, the process ends.

Step S506
Using the symmetric encryption algorithm 321, the encrypted data 142 e stored in the disk memory 142 is decrypted using the encryption key 143 b decrypted and extracted in step S 503 or the encryption key acquired in step S 504, and stored as data 143 a. By expanding to 143, an editable state is set.

  When the decrypted data 143a is edited by the data editing algorithm 141a1 and then encrypted again and stored in the disk memory 142, the encryption key extracted in step S503 or step S504 is used.

  FIG. 6 is a flowchart of client authentication processing (steps S401 and S501 described above and step S901 described later) in the portable terminal 14. This client authentication process is performed by communicating with the authentication server 12 or comparing hash values.

Step S601
The user identification information input from the user identification information input device 147 or the external key A input from the external key input device 146 is acquired.

Step S602
The process branches after checking whether the portable terminal 14 is online or offline.

Step S603
When online, authentication information (user identification information and external key A) is transmitted to the authentication server 12.

Step S621
The authentication server 12 receives the authentication information transmitted from the portable terminal 14 and performs authentication by comparing the received authentication information with the authentication information database 122a held in the disk memory 122.

Step S622
The authentication server 12 transmits the authentication result to the portable terminal 14.

Step S604
The portable terminal 14 receives the authentication result transmitted from the authentication server 12.

Step S605
Check the received authentication result and branch processing. If the authentication fails, the process moves to step S614 to execute an authentication failure output process.

Step S606
If the authentication is successful, the presence of the hash value 142b of the external key A is checked and the process branches.

Step S607
When the hash value 142 b of the external key A exists in the disk memory 142, the input hash value of the external key A is compared with the hash value 142 b of the external key A stored in the disk memory 142.

Step S608
The process branches after checking the hash value match / mismatch. If they match, the process proceeds to processing step S615 to execute an authentication success output process.

Step S609
If the hash values do not match in step S608 and if the hash value 142b of the external key A does not exist in step S606, the hash value of the external key A input to reflect the change of the authentication information is stored in the external The hash value 142b of the key A is stored in the disk memory 142.

Step S610
An authentication change output process for outputting the authentication result as a change is executed and the process ends.

Step S611
If it is not in the online state (in the offline state) in the branch of step S602, the presence of the hash value 142b of the external key A in the disk memory 142 is checked and the process branches. If the hash value 142b of the external key A does not exist, since authentication cannot be performed, the process proceeds to step S614 as an authentication failure, and an authentication failure output process is executed.

Step S612
When the hash value 142a of the external key A exists, the input hash value of the external key A is compared with the stored hash value 142a of the external key A.

Step S613
Check the comparison result and branch the process.

Step S614
If they do not match, the authentication failure output process is executed and the process ends.

Step S615
If they match, the authentication success output process is executed and the process ends.

  FIG. 7 is a flowchart of processing in which the portable terminal 14 acquires an encryption key from the key management server 11.

Step S701
The authentication information and the external key B encrypted key 142 c are transmitted from the portable terminal 14 to the key management server 11.

Step S711
The key management server 11 receives the authentication information and the external key B encrypted key 142 c transmitted from the portable terminal 14 and transmits the authentication information to the authentication server 12.

Step S721
The authentication server 12 receives the authentication information transmitted from the key management server 11 and performs server authentication processing by comparing the authentication information with the authentication information database 122a by the authentication function 121.

Step S722
The authentication result is transmitted to the key management server 11.

Step S712
The key management server 11 receives the authentication result from the authentication server 12.

Step S713
The process branches according to the authentication result.

Step S714
If authenticated, the key decryption function 111 performs decryption using the private key 112B of the external key B, and extracts the encryption key and user identification information.

Step S715
The user identification information extracted by decryption is compared with the user identification information in the authentication information received in step S711.

Step S716
The process branches according to the comparison result in step S715.

Step S717
If the comparison results match, the encryption key is transmitted to the portable terminal 14.

Step S718
If the comparison result and the comparison result do not match, it is transmitted to the portable terminal 14 that the encryption key cannot be transmitted.

Step S702
The portable terminal 14 receives the encryption key from the key management server 11 and encrypts the encryption key with the external key A so that the encryption key does not have to be acquired from the key management server 11 from the next time onward. It is stored in the disk memory 142 as the encrypted key 142d.

Step S703
The encryption key acquisition success output process is executed and the process ends.

Step S704
When it is received from the key management server 11 that the encryption key cannot be transmitted, the encryption key acquisition failure output process is executed and the process is terminated.

  Thus, by confirming the user identification information of the user who operates the portable terminal 14, it is possible to prevent an arbitrary user from illegally accessing the data by decrypting the encryption key of another person.

  FIG. 8 is a flowchart of processing for changing the encryption key in the portable terminal 14. As a premise of this processing, it is assumed that the external key A and the old encryption key have been acquired by the processing shown in FIGS.

Step S801
All of the data 142e held in the disk memory 142 is decrypted with the old encryption key and is expanded in the memory 143 as data 143a.

Step S802
Generate a new encryption key.

Step S803
The generated new encryption key is encrypted with the external key A and stored in the disk memory 142 as the external key A encrypted key 142d.

Step S804
The encryption key and user identification information generated in step S802 are encrypted with the public key 142a of the external key B, and stored in the disk memory 142 as the external key B encrypted key 142c. Accordingly, the external key A encrypted key 142d and the external key B encrypted key 142c stored in the disk memory 142 in the portable terminal 14 become information on the new encryption key generated in step S802.

Step S805
Data 143a expanded on the memory 143 is encrypted with a new encryption key and stored in the disk memory 142 as encrypted data 142e. Note that if the encryption key is different for each medium or data, steps S801 to S805 are repeated for each medium or data using the old encryption key.

  When the user changes the information of his / her external key A from another portable terminal 14A, or when the user loses the external key A and the administrator reissues the external key A, the authentication information of the authentication server 12 The information of the external key A registered in the database 122a and the information of the external key A stored as the external key A hash value 142b in the portable terminal 14A are different. In the decryption process shown in FIG. Since the authentication result is changed in the process and the encryption key acquisition process is performed, the data can be decrypted.

The second embodiment is an example in which a symmetric key managed by the key management server 11 is used as the external key B. A symmetric key is a key whose public key and private key are the same. In the second embodiment, in FIG. 3, the terminal 14 does not have the public key 142a of the external key B, and the external key B is managed in the key management server 11, and is used for encryption and decryption. Become common. Further, the terminal 14 does not have the asymmetric encryption algorithm 141a3, and instead, a key encryption function is provided in the key management server 11. Further, in place of step S405 in FIG. 4 and step S804 in FIG. 8, encryption by the external key B is requested by requesting the key management server 11 from the portable terminal 14 via a concealed communication path on the network. The user identification information input from the key 143b and the user identification information input device 147 is encrypted.
Therefore, in the second embodiment, the flowchart of the process when the portable terminal 14 generates the encryption key and encrypts the data is as shown in FIG. 9 instead of FIG.

Step S901
Before generating the encryption key, the client authentication process described with reference to FIG. 6 is performed.

Step S902
Check the authentication result and branch the process. If the authentication result is a failure, the application program is terminated without generating a key and encrypting data.

Step S903
If the authentication result is successful or changed, the encryption key generation algorithm 141a2 is used to generate a random encryption key based on the internal state of the terminal 14 and hold it as the encryption key 143b in the memory 143.

Step S904
The encryption key 143b held in the memory 143 is encrypted with the external key A input from the external key input device 146 by the first symmetric encryption algorithm 141a3 and stored in the disk memory 142 as the external key A encrypted key 142d. .

Step S905
Authentication information, encryption key 143 b and user identification information 147 are transmitted from the portable terminal 14 to the key management server 11.

Step S911
The key management server 11 receives the authentication information, the encryption key 143 b and the user identification information 147 transmitted from the portable terminal 14 and transmits the authentication information to the authentication server 12.

Step S921
The authentication server 12 receives the authentication information transmitted from the key management server 11 and performs server authentication processing by comparing the authentication information with the authentication information database 122a by the authentication function 121.

Step S922
The authentication result is transmitted to the key management server 11.

Step S912
The key management server 11 receives the authentication result from the authentication server 12.

Step S913
The process branches according to the authentication result.

Step S914
If authenticated, the encryption key 143b and the user identification information 147 are encrypted using the external key B by the key encryption function in the key management server 12.

Step S915
The external key B encrypted key encrypted in step S914 is transmitted to the portable terminal 14.

Step S916
If not authenticated in step S913, the mobile terminal 14 is transmitted to the effect that the external key B encrypted key cannot be transmitted.

Step S906
The portable terminal 14 receives the external key B encrypted key from the key management server 11 and stores it in the disk memory 142 as the external key B encrypted key 142c.

Step S907
After the encryption key 143b generated by the above processing is encrypted and securely stored in the disk memory 142, the data 143a in the memory 143 is encrypted by using the encryption key 143b by the second symmetric encryption algorithm 141a5, and the disk The encrypted data 142e is stored in the memory 142.

Step S908
When receiving from the key management server 11 that the encryption key cannot be transmitted, the application program is terminated without performing data encryption.

  In the information processing apparatus according to the third embodiment, the system administrator manages the external key B in place of the key management server 11, and information that only the system administrator can know, such as a password indicated by the system administrator, is stored in the external key B. 4, instead of the processing of step S405 in FIG. 4 and step S804 in FIG. 8, a screen prompting the system administrator to input the secret key B is displayed on the portable terminal 14, and the system administrator The encryption key 143b and the user identification information input from the user identification information input device 147 can be encrypted with the input secret key B. Further, instead of S711 to S715 in FIG. 7, a screen prompting the system administrator to input the secret key B is displayed on the portable terminal 14, and the external key is input by the secret key B input by the system administrator. The B encrypted key 142c can be decrypted.

  Although the first to third embodiments have been described by taking the portable terminal 14 as an example, the present invention can also be implemented in the same manner even if configured using other types of terminals such as desktop terminals.

  Encryption with the external key A and the external key B is independent of the content of the encryption key and the type of the data encryption algorithm. Therefore, it is possible to use different encryption keys 143b and data encryption algorithms 141a5 for each portable terminal, medium, and data.

  FIG. 10 is a functional block diagram of the terminal 14 in the fifth embodiment. This is a configuration in which different encryption keys are used for data 1 and data 2, and external key B encrypted key 142c1 and external key A encrypted key 142d1 corresponding to data 1 and external key B encrypted key corresponding to data 2 142c2 and external key A encrypted key 142d2 are stored in the disk memory 142, respectively.

Further, the second target encryption algorithm 141a5 can be configured to use different algorithms for the encryption key corresponding to the data 1 and the encryption key corresponding to the data 2.
At that time, the external key A and the external key B used for encryption of the encryption key are the same for the data 1 and the data 2, so that the user can use either the data 1 or the data 2. A common external key A can be used.

It is a block diagram which shows the structure of the information processing apparatus of Example 1 of this invention. 3 is a functional block diagram of a key management server, an authentication server, and a portable terminal in the information processing apparatus of Embodiment 1. FIG. 3 is a functional block diagram for data editing / encryption / decryption processing in a portable terminal in the information processing apparatus of Embodiment 1. FIG. 4 is a flowchart of processing when generating an encryption key and encrypting data in a portable terminal in the information processing apparatus according to the first embodiment. 6 is a flowchart of processing when decrypting encrypted data in the portable terminal in the information processing apparatus according to the first embodiment. 3 is a flowchart of client authentication processing in the information processing apparatus according to the first embodiment. 3 is a flowchart of processing in which a portable terminal in the information processing apparatus according to the first embodiment acquires an encryption key from a key management server. 6 is a flowchart of processing in which the portable terminal in the information processing apparatus according to the first embodiment changes an encryption key in the portable terminal. 10 is a flowchart of processing when generating an encryption key and encrypting data in a portable terminal in the information processing apparatus according to the second embodiment. FIG. 10 is a functional block diagram of a terminal in an information processing apparatus according to a fifth embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Key management server, 12 ... Authentication server, 14, 14A, 14B ... Portable terminal, 13, 15 ... Network, 111 ... Microprocessor, 111a ... Key decryption function, 112 ... Disk memory, 112a ... Release of external key B Key 112b: Private key of external key B 113 Communication means 121 Microprocessor 121a Authentication function 122 Disk memory 122a Authentication information database 141 Microprocessor 141a Application program 142 Disk Memory 142a ... Public key of external key B 142b ... Hash value of external key A 142c ... External key B encrypted key 142d ... External key A encrypted key 142e ... Encrypted data 143 ... Memory 143a ... Data, 143b ... encryption key, 144 ... communication means.

Claims (9)

In an information processing apparatus comprising a terminal connected to a network and a server, the terminal encrypting and storing data using an encryption key,
The terminal stores a first means A that stores an external key A encrypted key obtained by encrypting an encryption key using information (external key A) that is known only to the user, such as a password given by the user, A second means B for storing the user identification information and the external key B encrypted key using the external key B given by the server, and the terminal when the user loses the external key A A third means for requesting the server to decrypt the external key B encrypted key and obtaining an encryption key returned from the server;
The information processing apparatus comprising: means for returning an encryption key to the terminal after confirming the validity of the user based on the user identification information decrypted based on the external key B encrypted key from the terminal. In an information processing terminal that can be connected to a server via a network,
In order to store a key (encryption key) used for data encryption, an external key A is encrypted by encrypting the encryption key using information (external key A) that only the user knows, such as a password given by the user. A first means A for storing the encrypted key; and a second means for storing the user identification information and the encrypted key using the external key B given from the server in the network connection state. Means B, and when the user loses the external key A, the encryption key decrypted from the server by requesting the server to decrypt the external key B encrypted key held in the terminal An information processing apparatus comprising a third means for acquiring a key.   In claim 1, when an asymmetric key is used as the external key B, the process of encrypting the user identification information and the encryption key by distributing the public key of the external key B from the server to the terminal in advance is performed in the terminal. The information processing apparatus is characterized in that the private key of the external key B is held in the server, and the decryption request from the terminal is made via a concealed communication path on the network.   In claim 1, when a symmetric key is used for the external key B, the server holds the external key B, encrypts the user identification information and the encryption key, and decrypts the external key B encrypted key. An information processing apparatus, which performs the request from the terminal to the server via the upper concealed communication path.   The encryption / decryption of data using information that only the system administrator knows as the external key B, such as a password indicated by the system administrator in place of the server in the external key B, is the system management. An information processing apparatus characterized in that a user inputs the external key B to the terminal.   2. The information processing apparatus according to claim 1, wherein the encryption key and the data encryption algorithm can be used differently for a plurality of terminals.   In claim 1 or 2, when using the encryption method using an asymmetric key according to claim 3, the terminal holds the public key of the external key B inside and performs all encryption processing of the encryption key. An information processing apparatus characterized in that an encryption key can be changed offline even when performed in a terminal.   The external key A encrypted key, the external key B encrypted key, and the encrypted data are managed on a medium or data basis, and different encryption keys and data encryption algorithms can be used depending on the medium or data. Information processing apparatus.   In any one of claims 1 to 8, even when different encryption keys and data encryption algorithms are used depending on the medium or data, the encryption key encryption process is made common so that the one time given by the user An information processing apparatus, wherein a medium or data encrypted with a different encryption key and data encryption algorithm can be decrypted with the external key.

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