JP2006185184A - Authority management system, authentication server, authority management method, and authority management program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more properly manage users' authorities by preventing leakage of distributed information and secret information restored by using distributed information. <P>SOLUTION: An authentication server 2 includes; a token generation means which generates tokens being data indicating addresses of distributed information, for each user and transmits the tokens to respective users; a transfer means which transfers a token generated for each user to users other than the user; an acquisition means which accepts a request message for a privilege account being a prescribed operation authority and transmits addresses of tokens included in the request message to a secrecy management server 3 and acquires a result of whether decoding secret information by using distributed information corresponding to the addresses is successful or not from a secrecy management server 3; and an account giving means which gives a privilege account to the user who has transmitted the request message, for successful decoding. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to authority management technology for managing user authority.

  In recent years, security technology using a secret sharing method has been studied. For example, Non-Patent Document 1 describes a method of multiplexing a cipher using a secret sharing method. The secret sharing method is a security technology that can divide secret information into a plurality of shared information (divided data) and restore it to the secret information of the original data only when a predetermined number or more of the shared information is collected.

Patent Document 1 describes an authentication technique for preventing leakage of shared information divided using a secret sharing method using a user ID and a password.
JP 2003-333028 A Okamoto Tatsuaki, “Contemporary Cryptography”, Sangyo Tosho, 1997, p. 216

  By the way, in the secret sharing method, secret information cannot be restored unless a predetermined number of pieces of shared information are collected. However, once the predetermined number or more of the shared information is collected, the secret information can be restored any number of times using the shared information. Further, when the secret information restored using the shared information is restored on a device accessible to the user, there is a risk that the secret information is leaked and reused for illegal purposes. Note that these are not considered in the authentication technique described in Patent Document 1.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent the leakage of shared information and secret information restored using the shared information, and more appropriately manage user authority. is there.

  In order to solve the above-described problem, in the present invention, the use right of the shared information assigned to each user is managed using a token indicating the address of the shared information.

  For example, the first aspect of the present invention is an authority management system having an authentication server that manages authority of a plurality of users and a plurality of terminals used by each of the plurality of users, and each user is assigned to the user. And the authority to use the distributed information obtained by dividing the predetermined secret information. Each terminal has a storage means for storing a token, which is data indicating the address of the shared information, and a shared information own token for which the own user using the terminal is authorized, or other users other than the own user Receives other tokens of the distributed information having the authority to use from the authentication server, and transmits the token receiving means for storing in the storage means and the own token stored in the storage means to the authentication server, and transfers the own token to another user. A token transfer unit; and a request message transmission unit configured to transmit a request message for requesting a privileged account having a predetermined operation authority to the authentication server together with the token stored in the storage unit. The authentication server generates, for each user, a user's own token, and transmits the token generated by the user to the terminal used by the user, and forwards the token transmitted from each terminal to another terminal of another user. Forwarding means, address sending means for receiving the request message and transmitting the address of each token included in the request message to an external system for decrypting the secret information, and the external system using the distributed information corresponding to the address Account decryption means for granting a privileged account to the user who transmitted the request message when the information is successfully decrypted.

  The second aspect of the present invention is an authority management system having an authentication server for authenticating the authority of a plurality of users and a secret management server for managing secret information, wherein the secret information is encrypted with a plurality of encrypted information. Divided into shared information, each user has the authority to use any of the shared information assigned to the user. Then, the authentication server generates a token that is data indicating the address of the shared information for each user, and transmits a token generation unit that transmits the token to each user, and the token generated for each user to a user other than the user. Whether the transfer means and the request message of the privileged account that is the predetermined operation authority are accepted, the address of each token included in the request message is sent to the secret management server, and whether or not the secret information has been successfully decrypted from the secret management server Acquisition means for acquiring the success / failure result and account granting means for granting a privileged account to the user who transmitted the request message when the secret information is successfully decrypted. Then, the secret management server receives the address from the shared information management database for managing a plurality of shared information and the acquisition means of the authentication server, and acquires the shared information corresponding to the address by referring to the shared information management database. A decrypting unit that decrypts the secret information using the shared information; and a transmitting unit that transmits a success / failure result indicating whether the decryption performed by the decrypting unit is successful or not to the authentication server.

  According to a third aspect of the present invention, there is provided an authentication server in an authority management system having an authentication server for authenticating the authority of a user and a secret management server for managing secret information. Each of the users has the authority to use any of the shared information assigned to the user. Then, the authentication server generates a token that is data indicating the address of the shared information for each user, and transmits a token generation unit that transmits the token to each user, and the token generated for each user to a user other than the user. The transfer means and a request message of a privileged account that is a predetermined operation authority are received, the address of each token included in the request message is transmitted to the secret management server, and the secret information is decrypted using the distributed information corresponding to the address. It has an acquisition means for acquiring a success / failure result indicating whether or not it is successful from the secret management server, and an account granting means for granting a privileged account to the user who transmitted the request message when the secret information is successfully decrypted.

  In the present invention, the authority of a user is more appropriately managed by preventing leakage of secret information restored using shared information.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is an overall configuration diagram of an authority management system to which an embodiment of the present invention is applied.

  As shown in the figure, the authority management system according to the present embodiment includes a plurality of authentication terminals 1, an authentication server 2, a secret management server 3, and a VPN device 4. Each authentication terminal 1 is connected to the authentication server 2 via a network 5 such as the Internet. Note that after the authentication server 2 performs personal authentication processing described later, a VPN (Virtual Private Network) is generated in the network 5 and data is transmitted and received via the VPN device 4. Further, the authentication server 2 and the secret management server 3 are connected by, for example, a dedicated line (or LAN) 6 or the like.

  Each authentication terminal 1 is a terminal device used by each user. Each user is assumed to have the authority to use the distributed information assigned to the user in advance. The shared information is obtained by dividing secret information into a plurality of pieces by a predetermined method. The authentication server 2 manages the authority of each user. The secret management server 3 restores secret information from a predetermined number of shared information.

  The VPN device 4 is a device for performing communication using VPN. The VPN is a virtual private line constructed in the network 5 such as the Internet. In VPN, since communication bases are connected to each other like a dedicated line, highly confidential communication can be realized. The VPN device 4 generates and manages a VPN session (connection).

  Next, the authentication terminal 1 will be described in more detail.

  FIG. 2 is a diagram illustrating a functional configuration of the authentication terminal 1. The authentication terminal 1 includes an input receiving unit 11, a processing unit 12, an output unit 13, and a storage unit 14, as illustrated. The input reception unit 11 receives various operation instructions input using an input device (not shown). The processing unit 12 performs processing according to the instruction received by the input receiving unit 11. The output unit 13 outputs various information to an output device (not shown). The storage unit 14 stores a token (not shown) transmitted from the authentication server 2. The token is data in which an address (pointer) that is a storage location of shared information is set. The token will be described later.

  Next, the authentication server 2 will be described in more detail.

  FIG. 3 is a diagram illustrating a functional configuration of the authentication server 2. As illustrated, the authentication server 2 includes an authentication unit 21, a token management unit 22, a monitoring unit 23, and a storage unit 25. The authentication unit 21 performs user personal authentication based on authentication information transmitted from each user. The token management unit 22 generates and manages a token for each user. The monitoring unit 23 transmits the token transfer status and the operation content transmitted from each authentication terminal to the authentication terminal.

  The storage unit 25 stores an authentication DB 26 and a management DB 27. The authentication DB 26 is a database for authenticating (determining) the validity of each user. The authentication DB 26 stores a user ID and a hash value of authentication information for each user. In the present embodiment, a user ID and a password are used as authentication information. The management DB 27 is a database that stores tokens generated by the token management unit 22. The token management DB 27 stores a token generated for each user and a hash value of the encrypted token.

  Next, the secret management server 3 will be described in more detail.

  FIG. 4 is a diagram showing a functional configuration of the secret management server 3. As illustrated, the secret management server 3 includes a shared information generation unit 31, a shared information decryption unit 32, a data management unit 33, and a storage unit 34.

  The shared information generating unit 31 uses the secret sharing method to divide the secret information (original data) into a plurality of pieces of shared information while encrypting the secret information (original data). Note that the authority to use each of the generated shared information is assigned to each user in advance. The shared information decoding unit 32 restores secret information (original data) from each shared information when a certain number of shared information is prepared. The data management unit 33 searches the shared information management DB 35 stored in the storage unit 34 for the address of the shared information.

  The storage unit 34 stores a distributed information management DB 35. The shared information management DB 35 is a database that stores an address (pointer) that is a storage location of each shared information generated by the shared information generating unit 31. It is assumed that the shared information management DB 35 of this embodiment stores an address and the shared information itself in association with each shared information. However, the present invention is not limited to this, and the distributed information itself may be stored in another computer device (not shown). For example, the shared information management DB 35 may set a URL (Uniform Resource Locator) in which shared information is stored instead of storing the shared information itself. Note that the user ID is included in the address.

  The authentication terminal 1, authentication server 2, and secret management server 3 described above all include a CPU 901, a memory 902, an external storage device 903 such as an HDD, a keyboard, a mouse, and the like as shown in FIG. A general-purpose computer system including an input device 904, an output device 905 such as a display or a printer, and a communication control device 906 for network connection can be used. In this computer system, the CPU 901 executes a predetermined program loaded on the memory 902, thereby realizing each function of each device.

  For example, the functions of the authentication terminal 1, the authentication server 2, and the secret management server 3 are as follows: the CPU 901 of the authentication terminal 1 is a program for the authentication terminal 1, and the authentication server 2 is a program for the authentication server 2. When the CPU 901 is a program for the secret management server 3, the CPU 901 of the secret management server 3 executes the program. The storage unit 14 of the authentication terminal 1 includes the memory 902 or the external storage device 903 of the authentication terminal 1, the storage unit 25 of the authentication server 2 includes the memory 902 or the external storage device 903 of the authentication server 2, and The storage unit 34 of the secret management server 3 uses the memory 902 or the external storage device 903 of the secret management server 3. Further, regarding the external storage device 903, the input device 904, and the output device 905, each device is provided as necessary.

  Next, an outline of the processing of this system will be described.

  In the present embodiment, it is assumed that the secret management server 3 divides secret information into a plurality of pieces of shared information using a (K, N) threshold method which is one of secret sharing methods. The (K, N) threshold method is a method in which secret information is divided into N pieces of distributed information while being encrypted, and the secret information can be restored only when K (K ≦ N) or more are collected.

  FIG. 6 is a diagram schematically showing the processing of this system. In the present embodiment, the secret information is divided into 4 (N = 4) pieces of shared information, and can be restored only when 3 (K = 3) pieces of shared information are collected (3, 4). An example of the threshold method will be described below.

  In the example shown in the figure, it is assumed that user A, user B, user C, and user D have usage authority for each of the four pieces of shared information. And each user accesses the authentication server 2 using each authentication terminal (authentication terminal A, authentication terminal B, authentication terminal C, and authentication terminal D). And the authentication server 2 performs the personal authentication which discriminate | determines whether each user is a valid user using the authentication information transmitted from each authentication terminal (S10).

  When it is determined that the user is a valid user, the authentication server 2 generates a token in which the address of the distributed information assigned to each user is set, and transmits the token to each authentication terminal. By acquiring the token, the user can exercise (own) the right to use the shared information indicated by the token.

Then, the user can transfer the token for the user received from the authentication server 2 to another user. As a result, the user delegates the authority to use his / her distributed information to other users. In the illustrated example, the user A and the user C use the authentication terminal A and the authentication terminal C to transfer the token 8A of the user A and the token 8C of the user C to the authentication terminal B of the user B (S30).
User B has the authority to use the shared information of other users with the transferred token. In the present embodiment, since the (3,4) threshold method is used, the user B has the authority to decrypt the secret information when the user B has the authority to use three or more pieces of shared information. That is, when the user B has three or more tokens, the user B can be promoted to a privileged user having a privileged account that is a collective authority of all users.

  In the illustrated example, the user B owns his token 8B and the two tokens 8A and 8C of the transferred user A and user B. Therefore, the user B transmits the acquired three tokens to the authentication server 2 using the authentication terminal B. Then, the authentication server 2 performs collective authentication of the token received from the authentication terminal B (S50). That is, the authentication server 2 transmits the address of each received token to the secret management server 3. Then, the authentication server 2 receives a success / failure result indicating whether or not the secret information has been successfully restored from the secret management server 3 and determines whether or not to grant a privilege account to the user B according to the success / failure result.

  Since the user B has three tokens at this time, the secret management server 3 succeeds in restoration. Then, the authentication server 2 gives a privilege account to the user B. User B obtains a privileged account and is deemed to have been delegated authority from all users and is promoted to a privileged user. Then, the user B who has become a privileged user acquires an authority to perform system management that is not permitted by a general user. For example, the authority to perform resource operations such as adding a hard disk of a computer, user operations such as changing a user ID, and data operations such as deleting a system log file is acquired.

  Also, the user A (or user C) who has transferred his token to another user can cancel the token transfer (token back) (S70). That is, the user A transmits an instruction to cancel the token 8A to the authentication server 2 using the authentication terminal A. Then, the authentication server 2 transmits the token 8A to the authentication terminal A of the user A, and performs collective authentication (S50) again in this state. In this case, the token acquired by the user B is two of the token 8B of the user B and the token 8C of the user C. That is, since the number of tokens is less than 3, the secret management server 3 cannot decrypt the secret information. Therefore, the authentication server 2 extinguishes the privilege account of the user B. Thereby, the user B is demoted from a privileged user to a general user.

  Next, the individual authentication process (S10), token transfer process (S30), collective authentication process (S50), and cancel process (S70) described in FIG. 6 will be described in more detail.

  FIG. 7 is a process flowchart of the personal authentication process (FIG. 6: S10).

  The user inputs the authentication information of the user using the input device of the authentication terminal 1. In the present embodiment, a user ID and a password are used as authentication information. And the input reception part 11 of the authentication terminal 1 receives the authentication information input from the user. Then, the processing unit 12 transmits the received authentication information to the authentication server 2 via the network 5 (S11).

  The authentication unit 21 of the authentication server 2 receives the authentication information and calculates a hash value of the received authentication information (S12). That is, the authentication unit 21 generates a fixed-length pseudorandom number from the user ID and password authentication information. And the authentication part 21 collates whether the calculated hash value corresponds with the hash value of the said user memorize | stored in authentication DB26 of the memory | storage part 25 (S13). It is possible to prevent leakage of authentication information by storing the hash value of the authentication information without storing the authentication information itself in the authentication DB 26.

  If the hash values match, the authentication unit 21 instructs the VPN apparatus 4 to generate a VPN (S14). The VPN apparatus 4 receives an instruction from the authentication server 2, generates a VPN in the network 5, and establishes a VPN session between the authentication server 2 and the authentication terminal 1. Note that after the VPN session is established, messages are transmitted and received between the authentication server 2 and the authentication terminal 1 by the VPN via the VPN device 4. And the authentication part 21 of the authentication server 2 transmits the authentication result (the collation result whether a hash value matched) to the authentication terminal 1 via the VPN apparatus 4 (S15).

  The processing unit 12 of the authentication terminal 1 receives the authentication result (S16). In the illustrated example, it is assumed that the authentication is successful (that is, the hash values match). When authentication fails in S13 (that is, when it does not match the hash value of the authentication DB), the processing unit 12 controls the output unit 13 to output an error message indicating that authentication has failed to the output device. Then, the personal authentication process is terminated.

  And the input reception part 11 of the authentication terminal 1 receives the input of the token request | requirement instruction | indication which the user input using the input device. Then, the processing unit 12 transmits a token request message to the authentication server 2 via the VPN device 4 (S17).

  When the token management unit 22 of the authentication server 2 receives the token request message, the token management unit 22 accesses the secret management server 3 and acquires the storage location of the distributed information for which the user has authority to use (S18). That is, the token management unit 22 requests an address (pointer) that is a storage location of shared information assigned to the user, using the user ID as a search key. The data management unit 33 of the secret management server 3 searches for an address including the user ID stored in the distributed information management DB 35 and transmits the searched address to the authentication server 2.

  Then, the token management unit 22 of the authentication server 2 generates a token including the address of the shared information (S19). That is, the token management unit 22 generates a token including the address of the shared information, the expiration date, and the session number. The token data structure will be described later.

  The token management unit 22 encrypts the generated token using the authentication information transmitted from the authentication terminal 1 in S11, and calculates the hash value of the encrypted token (S20). Then, the token management unit 22 stores the token before encryption and the calculated hash value in the token management DB 27.

  Then, the token management unit 22 transmits the encrypted token to the authentication terminal 1 via the VPN device 4 (S21). Then, the processing unit 12 of the authentication terminal 1 receives the encrypted token from the authentication server 2 and stores the received token in the storage unit 14 (S22).

  In S20, by encrypting the token using the authentication information of the user who requested the token, the encrypted token cannot be decrypted by anyone other than the user who has input the authentication information. Further, by storing the hash value of the encrypted token in the token management DB 27, when the token is tampered, the token management unit 22 can easily detect the tampering of the talk.

  FIG. 8 is a diagram illustrating an example of a data structure of a token (before encryption).

  The token shown in the figure has a user ID 81, a secret information ID 82, a division information number 83, an expiration date 84, a session number 85, and a transfer partner 86. In this embodiment, the user ID 81, the secret information ID 82, and the division information number 83 are used as the address of the shared information acquired from the secret management server 3 in S18 of FIG. The secret information ID 82 is a unique identification number set by the shared information generation unit 31 of the secret management server 3. For example, the order (serial number) in which the shared information is generated from each secret information can be used. The division information number 83 is an identification number unique in each piece of shared information set when the shared information generating unit 31 divides the secret information into shared information. In this embodiment, since the information is divided into four pieces of shared information, one of the values 1 to 4 is set.

  In the expiration date 84, a time limit for using the token is set. The token management unit 22 of the authentication server 2 sets a date and time obtained by adding a predetermined period to the date and time when the token request message is received as the expiration date 84. The session number 85 is an identification number set by the token management unit 22 in order to identify a token. For example, the process ID or thread number of the authentication server 2 can be used. The transfer partner 86 is set with the user ID of another user who transferred the token in the token transfer process described below. Until the token transfer process is performed, the transfer partner 86 is a space (blank).

  Next, the token transfer process (FIG. 6: S30) will be described.

  FIG. 9 is a processing flowchart of token transfer processing. The token transfer process is a process performed after the authentication terminal 1 (user) acquires its own token. The token transfer process shown in the figure will be described by taking as an example a case where user A transfers a token to user B. The authentication terminal 1 used by the user A is the authentication terminal A, and the authentication terminal 1 used by the user B is the authentication terminal B.

  First, the user A inputs a token transfer instruction to transfer his token (hereinafter, “token A”) to the user B to the authentication terminal A using the input device. An input screen for inputting a token transfer instruction will be described later. Then, the input receiving unit 11 of the authentication terminal A receives a token transfer instruction including the user ID of the transfer partner (user B). Then, the processing unit 12 sends a token transfer message including the token A (encrypted state) stored in the storage unit 14 and the user ID of the user B who is the transfer partner via the VPN device 4 to the authentication server 2. (S31). Then, the processing unit 12 deletes the token A stored in the storage unit 14.

  Note that the user A may input the token expiration date in the token transfer instruction. In this case, the token transfer message includes the input expiration date.

  The token management unit 22 of the authentication server 2 receives the token transfer message and calculates the hash value of the token A included in the token transfer message. Then, the token management unit 22 collates the hash value of the token A stored in the token management DB 27 with the calculated hash value (S32). If the hash values do not match, the token management unit 22 determines that the token A transmitted from the authentication terminal A has been tampered with, and ends this process. On the other hand, when the hash values match, the token management unit 22 decrypts the encrypted token A using the authentication information of the user A (S33). Note that the authentication information of the user A is the user ID and password of the user A transmitted in S11 of the above personal authentication process (see FIG. 7), and is temporarily stored in the storage unit 25. .

  The token management unit 22 adds the transfer partner user ID included in the token transfer message to the transfer partner 86 of the decrypted token (see FIG. 8) (S34). If the token transfer message includes an expiration date, the expiration date is set (updated) to the expiration date 84 of the decrypted token.

  Then, the token management unit 22 encrypts the updated token A using the authentication information of the user A, and calculates the hash value of the encrypted token A (S35). Then, the token management unit 22 updates the token A and the hash value stored in the token management DB 27 in the personal authentication process (FIG. 7: S20).

  The token management unit 22 transmits the encrypted token A to the authentication terminal B of the user B via the VPN device 4 (S36). Then, the processing unit 12 of the authentication terminal B receives the encrypted token A from the authentication server 2 and stores the received token A in the storage unit 14 (S37). Note that it is assumed that the authentication terminal B logs in to the authentication server 2 in the personal authentication process shown in FIG. 7 and a VPN session is established.

  FIG. 10 is a diagram illustrating an example of a token transfer instruction input screen.

  The input screen shown is an example of an input screen when the user A transfers the token A to the user B in S31 of FIG. This screen includes a status display field 101 indicating the current token transfer status, a terminal input field 102, a user ID input field 103, an effective time input field 104, and an execution button 105.

  The status display column 101 shown in the figure indicates that there are currently two tokens transferred to the user B. In the terminal input field 102, identification information of the destination authentication terminal of the token to be transferred is input. In the example shown in the figure, identification information (Terminal B) of the authentication terminal B is input. In the user ID input field 103, the user ID of the token transfer partner is input. In the illustrated example, the user ID (User B) of the user B is input. In the valid time, the valid time or expiration date of the token to be transferred is input as necessary. The execution button 105 is an operation button for transmitting a token transfer instruction after the input to each input field is completed.

  Note that the token transfer status may be indicated using a display screen other than the status display field 101 in FIG.

  FIG. 11 is a diagram showing a token transfer state using a Petri net model. The Petri net model models the flow of information and signals in the system. In the illustrated example, as illustrated in FIG. 6, the user A and the user C transfer their tokens to the user B, thereby indicating that three tokens are collected for a predetermined user. Therefore, in the (3, 4) threshold method of the present embodiment, the illustrated Petri net model indicates that a predetermined user has a privileged account.

  It is assumed that the token transfer status shown in FIG. 10 or 11 is transmitted to the authentication terminal 1 by the monitoring unit 23 of the authentication server 2 in response to a request from the authentication terminal 1. That is, the monitoring unit 23 reads the transfer partner 86 of each token stored in the token management DB 27, and generates a token transfer status display screen. The user can determine the token transfer destination user by referring to the token transfer status.

  Next, the collective authentication process (FIG. 6: S50) will be described.

  FIG. 12 is a process flow diagram of the collective authentication process. The collective authentication process shown in the figure will be described by taking as an example a case where user B requests a privileged account. The storage unit 14 of the authentication terminal B of the user B stores “token B”, which is its own token, and “token A” and “token C” transferred from the user A and the user C. Shall.

  First, the input receiving unit 11 of the authentication terminal B receives a privileged account request instruction input by the user B using the input device. A privileged account is a special right granted only to users whose authority has been delegated from a certain number of users. A user who has been granted a privileged account acquires the authority to perform system management that is not permitted by general users. For example, the authority to perform resource operations such as adding a hard disk of a computer, user operations such as changing a user ID, and data operations such as deleting a system log file is acquired.

  Then, the processing unit 12 of the authentication terminal B reads the token A, token B, and token C stored in the storage unit 14, and transmits a privileged account request message including these tokens to the authentication server 2 (S51). Then, the processing unit 12 deletes the token A, token B, and token C from the storage unit 14.

  Then, the token management unit 22 of the authentication server 2 receives the privileged account request message via the VPN device 4. Then, the token management unit 22 calculates a hash value of each token included in the privileged account request message. Then, the token management unit 22 collates the hash value of each token stored in the token management DB 27 with the calculated hash value (S52).

  If there is even one token whose hash values do not match, the token management unit 22 determines that any of the tokens transmitted from the authentication terminal B has been tampered with, and ends this process. On the other hand, when the hash values of all tokens match the hash values of the token management DB, the token management unit 22 decrypts each encrypted token using the corresponding user authentication information (S53). That is, the token management unit 22 decrypts the token A using the authentication information of the user A, the token B using the authentication information of the user B, and the token C using the authentication information of the user C. Note that the authentication information of each user is the user ID and password of each user transmitted in S11 of the above personal authentication process (see FIG. 7), and is temporarily stored in the storage unit 25. .

  Then, the token management unit 22 determines, for each token, whether or not the expiration date set for the token has elapsed (S54). That is, the token management DB 22 determines whether or not the current time acquired by a function (system clock) such as an OS has passed the expiration date set for each token. If there is even one token that has expired, the token management unit 22 ends this process.

  When the expiration date of all tokens has not elapsed, the token management unit 22 for each token, the session number set in the token received from the authentication terminal B and the transfer partner, and the token stored in the token management DB 27 The session number and the transfer partner are collated (S54). That is, for example, in the case of token A, the token management unit 22 specifies the session number and transfer partner of the token A stored in the token management DB 27, and whether or not the session number and transfer partner set in the received token match. Is determined. If even one non-matching token exists, the token management unit 22 ends this process.

  When the session numbers and transfer partners match for all tokens, the token management unit 22 transmits the address set for each token to the secret management server 3 (S55). The addresses in the present embodiment are the token user ID 81, secret information ID 82, and division information number 83 shown in FIG.

  The shared information decrypting unit 32 of the secret management server 3 receives each address from the authentication server 2. Then, the shared information decoding unit 32 accesses the shared information management DB 35 using each received address as a search key, and acquires each shared information (S56). That is, the shared information decoding unit 32 reads the shared information corresponding to each address from the shared information management DB 35. If the address and the URL (Uniform Resource Locator) of the shared information are stored in the shared information management DB 35, the shared information decoding unit 32 accesses the URL corresponding to the received address and acquires the shared information. .

  Then, the shared information decrypting unit 32 decrypts the secret information from each acquired shared information, and transmits success or failure of decryption (whether or not the decryption is successful) to the authentication server 2 (S57). In the example shown in the figure, since three are decrypted using the shared information, the shared information decrypting unit 32 succeeds in decrypting the secret information.

  The token management unit 22 of the authentication server 2 receives the success or failure of the decryption. If the secret management server 3 succeeds in decryption, the token management unit 22 generates a privilege token for granting a privilege account to the user B (S58). The privilege token is the same as the token shown in FIG. However, it is assumed that a space is set in the privilege token division information number 83 and the transfer partner 86. The expiration date 84 is set to the shortest (closest) expiration date among the expiration dates set for each token.

  Then, the token management unit 22 encrypts the privilege token using a predetermined encryption phrase stored in the storage unit 25, and calculates the hash value of the encrypted token (S59). Then, the token management unit 22 stores the privilege token before encryption and the calculated hash value in the token management DB 27.

  Then, the token management unit 22 transmits the generated privilege token to the authentication terminal B of the user B (S60). The processing unit 12 of the authentication terminal B receives the privilege token and stores it in the storage unit 14 (S61). User B becomes a privileged user having a privileged account by acquiring a privileged token. Thereby, for example, the user B obtains the authority to perform resource operations such as adding a hard disk of a computer, user operations such as changing a user ID, and data operations such as deleting a system log file.

  Note that the user B transmits a privilege token to the authentication server 2 using the authentication terminal B when performing a special operation using the privileged account. The token management unit 22 of the authentication server 2 collates the hash value and session number of the privilege token with the hash value and session number stored in the token management DB 27. In addition, the token management unit 22 determines whether the expiration date of the privilege token has elapsed. After confirming the validity of the privilege token in this way, the token management DB 22 determines that the user B is a privileged user. Thereby, the user B can perform various operations using a special operation authority.

  Next, the cancellation process (FIG. 6: S70) will be described. The user A and the user C who have transferred the token to the user B can monitor the operation content of the user B from each authentication terminal. When it is determined that the user B is performing an illegal operation, the user A and the user C can cancel (retract) the token once transferred. The operation details monitoring screen will be described later.

  FIG. 13 is a flowchart of the cancel process. The cancellation process shown in the figure will be described by taking as an example a case where the user A cancels the token A transferred to the user B.

  First, the input receiving unit 11 of the authentication terminal A receives a cancel instruction input by the user A using the input device. Then, the processing unit 12 of the authentication terminal A transmits a cancel message to the authentication server 2 (S71).

  The token management unit 22 of the authentication server receives the cancel message and specifies the token A of the user A stored in the token management DB 27. Then, the transfer partner 86 of the specified token A is updated to a space (S72). It is assumed that the user ID of user B is stored in the transfer partner before being updated to the space. Further, the token management unit 22 updates the session number 85 as necessary.

  The token management unit 22 encrypts the updated token A using the authentication information of the user A, and calculates a hash value (S73). Then, the token management unit 22 stores (updates) the updated token A and hash value in the token management DB 27. Then, the token management unit 22 transmits the encrypted token to the authentication terminal A (S74). Then, the authentication terminal A receives the token A and stores it in the storage unit 14 (S75). Thereby, the user A has the authority to use the distributed information assigned to the user A again.

  Then, the token management unit 22 re-evaluates the privilege account for user B. That is, the token management unit 22 transmits the address of each token currently held by the user B having the privileged account to the secret management server 3 (S76). In the illustrated example, since the token A of the user A is canceled, the token management unit 22 transmits the addresses stored in the two tokens of the token B and the token C to the secret management server 3.

  The shared information decrypting unit 32 of the secret management server 3 receives each address from the authentication server 2. Then, the shared information decoding unit 32 accesses the shared information management DB 35 using each received address as a search key, and acquires each shared information (S77). Then, the shared information decrypting unit 32 decrypts the secret information from each acquired shared information, and transmits success or failure of decryption (whether or not the decryption is successful) to the authentication server 2 (S78). In the example shown in the figure, the shared information decrypting unit 32 can acquire only two pieces of shared information, and therefore fails to decrypt the secret information.

  When the secret management server 3 decryption fails, the token management unit 22 of the authentication server 2 deletes the privilege account of the user B (S79). That is, the token management unit 22 deletes the privilege token from the token management DB 27. Then, the token management unit 22 instructs the VPN apparatus 4 to disconnect the VPN session with the authentication terminal B (S80). The VPN device 4 disconnects the VPN session with the authentication terminal B. As a result, the privilege account of user B disappears. Therefore, when the user B acquires the privileged account again, it is necessary to perform the collective authentication process shown in FIG.

  Next, the monitoring screen of the user's operation content will be described.

  FIG. 14 shows an example of a monitoring screen. The monitoring screen shown in the figure has an operation display unit 121 for displaying the operation contents of the token transfer destination user, and a cancel button 122 for inputting a token transfer cancel instruction. As shown in FIG. 6, when the user A transfers the token A to the user B, the operation content of the user B is displayed on the operation display unit 121 displayed on the authentication terminal A of the user A.

  The user A can detect an unauthorized operation (or a sign of an unauthorized operation) of the user B that is not assumed by referring to the operation content of the user B displayed on the operation display unit 121 as necessary. In the example shown in the figure, it is indicated that the user B has input a command for data deletion processing. Thereby, the user A recognizes that the user B may destroy important data. In this case, the user A presses the cancel button 122 and inputs a cancel instruction for the token transferred to the user B. Thereby, the cancellation process of FIG. 13 is executed. In addition to the data deletion process, the illegal operation may be a data download (copy) process to a storage medium (such as a flexible disk), an upload process of data stored in the storage medium, or the like.

  For example, when the authentication terminal in FIG. 1 accesses the authentication server using the UNIX (registered trademark) Telnet function, the monitoring unit 23 of the authentication server 2 redirects the keyboard input of the privileged user to the Telnet virtual terminal (tty). By doing so, the operation content of the privileged user is echoed back to the user authentication terminal as the token transfer source.

  The embodiment of the present invention has been described above.

  In this embodiment, the user has a part of authority to decrypt the secret information by holding the token in which the address of the shared information is stored instead of the shared information itself. Then, the user delegates the authority to decrypt the secret information by transferring his token to another user. Then, the authentication server 2 sends the address of each token received from the user to the secret management server 3 and grants a privileged account to the user based on the success / failure result of whether or not the restoration of the secret information is successful. Decide whether or not. Therefore, the user and the authentication server 2 accessible by the user cannot acquire the restored secret information. For this reason, in this embodiment, leakage of the restored secret information can be prevented and higher security can be ensured.

  Further, only the address of the shared information is stored in the token transmitted to the user, and the shared information itself is not stored in the token. That is, the shared information is hidden from the user without being disclosed. Therefore, even a user who has acquired a predetermined number or more tokens cannot restore secret information using the token itself. For this reason, a user's fraudulent act can be prevented.

  Further, even when the user has transferred the token to another user and delegated authority, the user can cancel the authority delegation. Accordingly, when a user having a privileged account performs an illegal operation, the privilege transfer can be canceled by canceling the authority transfer. That is, it is possible to check a user who has been granted a privileged account. It should be noted that other users who have been transferred the token cannot transfer the shared information itself illegally, for example, by copying the transferred token.

  In addition, the user can monitor the operation content of another user who has transferred the token. As a result, the user can detect an unauthorized operation (or a sign of unauthorized operation) of another user having a privileged account and cancel the token transfer. In addition, it is possible to check a user who is given a privileged account.

  In the present embodiment, the authentication server 2 encrypts the generated token using the user ID and password of the corresponding user, and transmits the encrypted token to the authentication terminal. As a result, the contents of the token (user ID, session number, etc.) can be rewritten to prevent an illegal act of acquiring another user's token.

  In this embodiment, the hash value of the encrypted token is stored in the token management DB 27 of the authentication server, so that even if the token is tampered with illegally, the hash stored in the token management DB 27 is stored. By comparing the values, tampering can be easily detected.

  In this embodiment, after the personal authentication process (see FIG. 7), each of the authentication terminals and the authentication server 2 transmits and receives data by VPN. Thereby, highly confidential communication can be realized. Moreover, impersonation by an unauthorized third party can be prevented.

  In addition, this invention is not limited to said embodiment, Many deformation | transformation are possible within the range of the summary. For example, in the above embodiment, shared information distributed using the secret sharing method is used. However, the present invention is not limited to this, and for example, an inference engine and an inference rule may be used for the secret management server. An inference engine is an artificial intelligence system (inference mechanism) that applies inference rules to derive conclusions from certain events. If the authority is distributed to N people, the inference rule that “the collective authentication succeeds when the authority of K people out of N people is complete” is applied, so that the device of the secret sharing method can be substituted. Good.

  In the present embodiment, the token generated by the authentication server 2 is stored in the storage unit 14 of the authentication terminal 1. However, the generated token may be stored in an IC card or the like. By storing the token in an IC card or the like, the user can easily carry the token. When storing a token in an IC card or the like, the authentication terminal 1 needs to include an IC card reader / writer device.

  In addition, the authority management system of this embodiment includes an authentication server 2 and a secret management server 3. However, the authentication server 2 may have the function of the secret management server 3.

1 is a diagram illustrating an overall configuration of an authority management system to which an embodiment of the present invention is applied. 2 is a diagram showing a functional configuration of an authentication terminal 1. FIG. It is a figure which shows the function structure of an authentication server. It is a figure which shows the function structure of a secret management server. It is a figure which shows the hardware structural example of each apparatus. It is the figure which showed typically the process outline | summary of the authority management system. It is a flowchart of a personal authentication process. It is a figure which shows an example of the data structure of a token. It is a process flowchart of a token transfer process. It is a figure which shows an example of a token transfer instruction | indication input screen. This is a Petri net model showing the token transfer status. It is a flowchart of collective authentication processing. It is a flowchart of a token transfer cancellation process. It is a figure which shows an example of the monitoring screen.

Explanation of symbols

  1: Authentication terminal, 11: Input receiving unit, 12: Processing unit, 13: Output unit, 14: Storage unit, 2: Authentication server, 21: Authentication unit, 22: Token management unit, 23: Monitoring unit, 25: Storage Unit: 26: authentication DB, 27: token management DB, 3: secret management server, 31: distributed information generation unit, 32: distributed information decryption unit, 33: data management unit, 34: storage unit, 35: distributed information management DB

Claims (14)

An authority management system comprising an authentication server that manages authority of a plurality of users, and a plurality of terminals used by each of the plurality of users,
Each of the users has an authority to use distributed information obtained by dividing predetermined secret information assigned to the user,
Each of the terminals
Storage means for storing a token which is data indicating an address of the shared information;
Receiving from the authentication server the local token of the shared information that the user using the terminal has the authority to use, or the other token of the distributed information that the other user other than the user has the authority to use, and storing it in the storage means Token receiving means to
Token transfer means for transmitting the local token stored in the storage means to the authentication server and transferring the local token to another user;
Request message transmission means for transmitting a request message for requesting a privileged account having a predetermined operation authority to the authentication server together with the token stored in the storage means;
The authentication server is
For each user, a token generating means for generating the user's own token and transmitting it to the user's own terminal used by the user;
Transfer means for transferring the own token transmitted from each of the terminals to another terminal of another user;
Address transmitting means for receiving the request message and transmitting the address of each token included in the request message to an external system for decrypting the secret information;
Account granting means for granting a privileged account to a user who sent the request message when the external system succeeds in decrypting the secret information using the shared information corresponding to the address. Permission management system. The authority management system according to claim 1,
Each of the terminals
A cancel instruction transmitting means for transmitting to the authentication server a cancel instruction for canceling the transfer of the own token transmitted by the token transfer means;
The address transmission means of the authentication server includes:
The cancellation instruction is received, and the address of each token included in the request message excluding the cancellation-instructed token is transmitted to the external system,
The account granting means of the authentication server is
When the external system fails to decrypt the secret information using shared information corresponding to the address, the granted privilege account is extinguished. The authority management system according to claim 1,
Each of the terminals
Further comprising authentication information transmitting means for transmitting the user authentication information;
The authentication server is
The authority management system further comprising: an encryption unit that receives the authentication information from each of the terminals and encrypts the token generated by the token generation unit using the authentication information. The authority management system according to claim 1,
Each of the terminals and the authentication server are connected using a virtual private line. An authority management system having an authentication server that authenticates authority of a plurality of users and a secret management server that manages secret information,
The secret information is divided into a plurality of encrypted shared information,
Each of the users has the right to use any of the shared information assigned to the user,
The authentication server is
A token generating means for generating a token, which is data indicating an address of the shared information, for each user and transmitting the token to each user;
Transfer means for transferring the token generated for each user to a user other than the user;
Whether a request message of a privileged account having a predetermined operation authority is received, the address of each token included in the request message is transmitted to the secret management server, and whether or not the secret information has been successfully decrypted from the secret management server Acquisition means for acquiring the success / failure result of:
An account granting means for granting a privileged account to the user who sent the request message when the secret information is successfully decrypted;
The secret management server
A distributed information management database for managing the plurality of shared information;
Decryption means for receiving the address from the obtaining means of the authentication server, obtaining the shared information corresponding to the address with reference to the shared information management database, and decrypting the secret information using the shared information;
An authority management system comprising: a transmission unit configured to transmit a success / failure result indicating whether or not the decryption performed by the decryption unit is successful to the authentication server. The authority management system according to claim 1 or 5, wherein
The privilege management system, wherein the secret information is divided into the plurality of pieces of shared information by a secret sharing method. An authentication server in an authority management system having an authentication server for authenticating user authority and a secret management server for managing secret information,
The secret information is divided into a plurality of encrypted shared information,
Each of the users has the right to use any of the shared information assigned to the user,
The authentication server is
A token generating means for generating a token, which is data indicating an address of the shared information, for each user and transmitting the token to each user;
Transfer means for transferring the token generated for each user to a user other than the user;
A privileged account request message having a predetermined operation authority is received, the address of each token included in the request message is transmitted to the secret management server, and the secret information is decrypted using the distributed information corresponding to the address. Acquisition means for acquiring a success / failure result indicating whether or not the transaction has succeeded from the secret management server;
An authentication server, comprising: an account grant unit that grants a privileged account to a user who has transmitted the request message when the secret information is successfully decrypted. The authentication server according to claim 7,
The token generation means acquires the address of each of the shared information from the secret management server, and generates the token. The authentication server according to claim 7,
A hash value calculating means for calculating a hash value of each token generated by the token generating means;
An authentication server, further comprising hash value storage means for storing the calculated hash value. The authentication server according to claim 7,
The success / failure acquisition unit receives a cancel instruction for canceling the token transfer performed by the transfer unit, and transmits the address of each token included in the request message excluding the cancel-instructed token to the secret management server. And obtaining from the secret management server a success / failure result indicating whether or not the secret information has been successfully decrypted using the shared information corresponding to the address,
The authentication server characterized in that the account granting means extinguishes the granted privileged account when decryption of the secret information fails. An authority management method in an authority management system having an authentication server that manages authority of a plurality of users and a plurality of terminals used by each of the plurality of users,
Each of the users has an authority to use distributed information obtained by dividing predetermined secret information assigned to the user,
Each of the terminals includes a storage unit that stores a token that is data indicating an address of the shared information, and a terminal processing unit.
The terminal processing unit
Receive from the authentication server the local token of the distributed information that the user using the terminal has the authority to use, or the other token of the distributed information that the other user other than the user has the authority to use, and store it in the storage unit A token receiving step,
A token transfer step of transmitting the own token stored in the storage unit to the authentication server and transferring the own token to another user;
A request message transmission step for transmitting a request message for requesting a privileged account having a predetermined operation authority together with the token stored in the storage unit to the authentication server,
The server processing unit of the authentication server is
For each user, a token generation step of generating the user's own token and transmitting it to the user's own terminal used by the user;
A transfer step of transferring the own token transmitted from each of the terminals to another terminal of another user;
An address transmission step of receiving the request message and transmitting an address of each token included in the request message to an external system that decrypts the secret information;
An account granting step of granting the privileged account to the user who sent the request message when the external system succeeds in decrypting the secret information using the shared information corresponding to the address, Permission management method. An authority management method in an authority management system having an authentication server for authenticating authority of a plurality of users and a secret management server for managing secret information,
The secret information is divided into a plurality of encrypted shared information,
Each of the users has the right to use any of the shared information assigned to the user,
The first processing unit of the authentication server includes:
A token generation step of generating a token, which is data indicating an address of the shared information, for each user and transmitting the token to each user;
A transfer step of transferring the token generated for each user to a user other than the user;
Whether a request message of a privileged account having a predetermined operation authority is received, the address of each token included in the request message is transmitted to the secret management server, and whether or not the secret information has been successfully decrypted from the secret management server An acquisition step of acquiring the success / failure result of
If the decryption of the secret information is successful, an account granting step for granting a privileged account to the user who sent the request message is performed.
The secret management server includes a shared information management storage unit for managing the plurality of shared information, and a second processing unit,
The second processing unit includes:
Receiving the dress from the authentication server, obtaining the shared information corresponding to the address with reference to the shared information management storage unit, and decrypting the secret information using the shared information;
And a transmission step of transmitting a success / failure result indicating whether or not the decryption of the decryption step is successful to the authentication server. An authority management method for the authentication server in an authority management system having an authentication server for authenticating user authority and a secret management server for managing secret information,
The secret information is divided into a plurality of encrypted shared information,
Each of the users has the right to use any of the shared information assigned to the user,
The authentication server processing unit includes:
A token generation step of generating a token, which is data indicating an address of the shared information, for each user and transmitting the token to each user;
A transfer step of transferring the token generated for each user to a user other than the user;
A privileged account request message having a predetermined operation authority is received, the address of each token included in the request message is transmitted to the secret management server, and the secret information is decrypted using the distributed information corresponding to the address. An acquisition step of acquiring a success / failure result indicating whether or not the transaction is successful from the secret management server;
An account granting step of granting a privileged account to a user who has transmitted the request message when the secret information is successfully decrypted. An authority management program executed by the authentication server in an authority management system having an authentication server for authenticating user authority and a secret management server for managing secret information,
The secret information is divided into a plurality of encrypted shared information,
Each of the users has the right to use any of the shared information assigned to the user,
In the processing unit of the authentication server,
A token generation step of generating a token, which is data indicating an address of the shared information, for each user and transmitting the token to each user;
A transfer step of transferring the token generated for each user to a user other than the user;
A privileged account request message having a predetermined operation authority is received, the address of each token included in the request message is transmitted to the secret management server, and the secret information is decrypted using the distributed information corresponding to the address. An acquisition step of acquiring a success / failure result indicating whether or not the transaction is successful from the secret management server;
An authority management program for executing an account granting step of granting a privileged account to a user who has transmitted the request message when the secret information is successfully decrypted.

Images