JP4498165B2 - Encryption communication key management apparatus and program - Google Patents

Description

  The present invention relates to an encryption communication key management apparatus for generating and managing encryption keys used in encryption communication via a network.

  An encryption communication technique called VPN (Virtual Private Network) for performing communication via a network such as the Internet more securely is known. VPN employs a security protocol called IPsec (IP Security) and a key exchange protocol called IKE (Internet Key Exchange). In this IKE key exchange method, a session key for encrypting communication data is obtained by performing predetermined encryption processing or the like on a shared key (secure channel key). This session key (encrypted communication key) is updated at a predetermined timing such as every predetermined time.

  There is also a system for safely performing encrypted communication between communication devices by performing encrypted communication using a key stored in an IC card (Patent Document 1).

JP 2004-40278 (4th, 5th page, FIG. 2)

However, the IKE key exchange method described above has a problem that throughput is reduced because it takes a long time to encrypt a secure channel key or the like for obtaining a session key.
Further, there is a possibility that information on the key is illegally acquired by disassembling and analyzing the inside of the communication device.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an encryption communication key management apparatus and the like that can improve the processing efficiency of encryption communication processing.
Another object of the present invention is to provide an encryption communication key management apparatus and the like that can perform encryption communication processing more safely.

In order to achieve the above object, an encryption communication key management apparatus according to the first aspect of the present invention provides:
Means for acquiring shared key information by a key exchange protocol using a secret key and a public key between the communication partner device that is the communication partner and the communication partner device ;
Extraction means for extracting a plurality of sets of first and second parameters for managing key data and key data from the shared key information;
Means for storing the key data extracted by the extracting means in a memory area that requires authentication by one of the first and second parameters at the time of access;
It means for the first and the one parameter of the second parameter acquired from the communication partner device, and outputs the other parameters for the communication partner device,
Obtaining means for accessing the memory area using the obtained one parameter and obtaining key data;
Means for outputting the key data obtained by the obtaining means as session key data;
It is characterized by providing.

The encryption communication key management apparatus may be realized by an IC chip.

The other parameter is used for authentication at the time of accessing key data stored in the memory area of the encryption communication key management device of the communication partner by the encryption communication key management device of the communication partner as the communication partner device. Also good.

A program according to the second aspect of the present invention is
Computer
Means for acquiring shared key information by a key exchange protocol using a secret key and a public key between the communication partner device that is the communication partner and the communication partner device ;
Extraction means for extracting a plurality of first and second parameters for managing key data and key data from the shared key information;
Means for storing the key data extracted by the extracting means in a memory area that requires authentication by one of the first and second parameters at the time of access;
It means for the first and the one parameter of the second parameter acquired from the communication partner device, and outputs the other parameters for the communication partner device,
An acquisition means for accessing the memory area using the acquired one parameter and acquiring key data;
Means for outputting the key data obtained by the obtaining means as session key data;
To function as.

  According to the present invention, the processing efficiency of encryption communication processing can be improved. In addition, the encryption communication process can be performed more safely.

Hereinafter, an encryption communication key management apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a case where the encryption communication key management apparatus is realized by an IC chip will be described as an example.
FIG. 1 shows a configuration example of a communication system including an encryption communication key management device (IC chip) according to an embodiment of the present invention. This communication system includes a communication device 2 on which an IC chip 1 is mounted. Each communication device 2 is connected via a network 10.

The IC chip 1 includes a CPU 11, a memory 12, and an input / output I / F (interface) 13.
The CPU 11 executes an operation program stored in the memory 12 to execute shared key information acquisition processing related to generation and management of a key (session key) for encrypting data exchanged between the communication devices 2, and session key output. Perform processing. In the shared key information acquisition process and the session key output process, data exchange with the communication partner IC chip 1 is performed via the communication device 2 to which the IC chip 1 is attached.

  In the shared key information acquisition process, the CPU 11 uses the public key pair (public key certificate and private key) stored in the memory 12 to perform a challenge / response authentication process with the IC chip 1 of the communication partner. To identify and authenticate each other (mutual authentication). If the identification and authentication are mutually successful, the CPU 11 uses the public key pair, a random number generated by the identification and authentication, and the like with the counterpart IC chip 1 according to a key exchange protocol such as a DH (Diffie-Hellman) method. Key exchange processing is performed between them to obtain shared key information. Then, the CPU 11 extracts a plurality of sets of key data SKi (i = 1 to n), IDi, and parameters VAKi and VBKi for managing the key data SKi from the acquired shared key information. Specifically, for example, the key data SKi, IDi, parameter VAKi, and parameter VBKi may be extracted by dividing the shared key information with a predetermined size.

  Then, the CPU 11 stores the extracted key data SKi, IDi, parameter VAKi, and parameter VBKi in a predetermined area of the memory 12. Specifically, when the IC chip 1 is the mutual authentication start side, the parameter VAKi is set as a “key (a key required to extract the partner side key data SKi)” to be supplied to the other party. In association with IDi, it is stored in the predetermined area X of the memory 12, and when it is a response side of mutual authentication authentication, the parameter VBKi is associated with IDi as a “key” supplied to the other party. To store. A “key identification code” indicating that the parameter is stored as a key is assigned to the parameter stored as the “key”. Further, when the CPU 11 is the mutual authentication start side, the parameter (VBKi) stored as “key” in the predetermined area Y of the memory 12 and “memory” in the other party is associated with IDi as “lock”. If the key data SKi is stored, and if it is a response side of mutual authentication, the parameter (VAKi) stored as a “key” in the predetermined memory area Y of the memory 12 is set to “lock”. The key data SKi is stored in association with IDi. Thus, the key data and the parameters for managing the keys are stored in the areas X and Y of the memory 12 of the IC chip 1 so as to face the IC chip 1 of the communication partner.

  In the session key output process, the parameter (VAKi or VBKi) stored in the area X is transmitted to the counterpart IC chip 1 together with IDi, and the parameter (VBKi or VAKi) received from the counterpart IC chip 1 is transmitted. The key data SKi (session key) is acquired by accessing the area Y of the memory 12 and output to the communication device 2.

The memory 12 includes a ROM, a RAM, and the like. An operation program to be executed by the CPU 11 and various data necessary for processing, a public key pair of the IC chip 1 (a public key certificate (including a public key) and a private key) Memorize etc. The memory 12 includes an area X in which the parameter VAKi or VBKi is stored in association with IDi, and an area Y in which the key data SKi is stored in association with IDi. The storage area of the key data SKi in the area Y is an area where access control is performed using the parameter VBKi or VAKi as a key.
The input / output I / F 13 controls communication between the IC chip 1 and the communication device 2.

The communication device 2 includes, for example, a router, a personal computer, a portable terminal, and the like, and includes a computer including a control unit 21, a storage unit 22, a communication unit 23, and an input / output I / F 24.
The control unit 21 includes a CPU, a ROM, a RAM, and the like, and performs various processes such as cryptographic communication with other communication devices 2 by executing an operation program stored in the storage unit 22. In encrypted communication processing with another communication device 2, a session key for encrypting / decrypting communication data is acquired in conjunction with the IC chip 1, and encrypted communication is performed using the acquired session key.
The storage unit 22 is composed of, for example, a hard disk device or the like, and stores programs executed by the control unit 21 and various data.
The communication unit 23 performs data communication with other communication devices 2 via the network 10.
The input / output I / F 24 controls communication with the IC chip 1.

  Next, the processing operation of the cryptographic communication key management apparatus (IC chip 1) according to the present embodiment will be described by taking as an example a case where cryptographic communication is performed between the two communication devices 2A and 2B. First, the shared key information acquisition process will be specifically described with reference to the flowchart of FIG. In the following description of the shared key information acquisition process and the session key output process, the IC chips 1 attached to the communication devices 2A and 2B are referred to as IC chips 1A and 1B, respectively, and the CPU 11 in the IC chips 1A and 1B is respectively referred to. Called CPU11A and CPU11B.

For example, the communication device 2A transmits an encrypted communication start request to the IC chip 1A in order to perform encrypted communication with the communication device 2B. In response to this request, the CPU 11A of the IC chip 1A transmits a mutual authentication request to the IC chip 1B attached to the communication device 1B of the communication partner via the communication device 1A. Then, the CPUs 11A and 11B of the IC chips 1A and 1B perform mutual authentication processing such as challenge / response authentication processing (step S1).
When the authentication in step S1 is successful (step S2: YES), the CPU 11A of the IC chips 1A and 1B uses, for example, a public key pair used in mutual authentication, a generated random number, or the like to use the DH (Diffie-Hellman) method. The key data SKi (i) is generated by performing key exchange processing with the counterpart IC chip 1 in accordance with a key exchange protocol such as the above to generate / acquire shared key information and delimit it with a predetermined size, for example. = 1 to n), IDi, parameter VAKi, and parameter VBKi are extracted in plural sets (n sets) (step S3).

Next, CPU11A, 11B discriminate | determines whether self is the start side of mutual authentication (step S4).
In the case of the IC chip 1A, since it is a mutual authentication start side (step S4: YES), the CPU 11A of the IC chip 1A sets the variable i = 1 (step S5), and then stores the parameter VAKi as a key. Is stored (stored) in the access-free area X in association with IDi (step S6). This parameter VAKi functions as a key necessary for extracting key data SKi from the counterpart IC chip 1B.
Next, the CPU 11A stores (stores) the key data SKi in the area Y where access is controlled in association with IDi (step S7). The CPU 11A sets the area Y so that it is necessary to authenticate with the parameter VBKi to which the “key identification code” is assigned when accessing the area of the key data SKi.
Next, the CPU 11A adds 1 to i (step S8), and determines whether i exceeds n (that is, whether the above processing is completed for all extracted key data SKi, parameters VAKi, VBKi, etc.). (Step S9) When i does not exceed n (Step S9: NO), the process returns to Step S6. If i exceeds n (step S9: YES), the shared key information acquisition process ends.

On the other hand, in the case of the IC chip 1B attached to the communication device 2B of the communication partner of the communication device 2A in step S4, since it is a response side of mutual authentication (step S4: NO), the CPU 11B of the IC chip 1B After setting the variable i = 1 (step S10), the parameter VBKi is stored (stored) in the access-free area X with a “key identification code” associated with IDi (step S11). This parameter VBKi functions as a key necessary for taking out key data SKi from the counterpart IC chip 1A.
Next, the CPU 11B stores (stores) the key data SKi in the area Y where access is controlled in association with IDi (step S12). The CPU 11B sets the area Y so that authentication by the parameter VAKi to which the “key identification code” is given is necessary when accessing the area of the key data SKi.
Next, the CPU 11B adds 1 to i (step S13), and determines whether i exceeds n (that is, whether the above processing has been completed for all extracted key data SKi, parameters VAKi, VBKi, etc.). (Step S14) If i does not exceed n (Step S14: NO), the process returns to Step S11. If i exceeds n (step S14: YES), the shared key information acquisition process ends.

  When the authentication in step S2 fails (step S2: NO), predetermined error processing such as sending an error signal to each communication device 2 is performed (step S15).

  For example, when the above-described shared key information acquisition process is finished, next, each IC chip 1A, 1B executes a session key output process. This session key output process will be described with reference to the flowchart of FIG.

After setting 1 to the variable i (step S21), the CPUs 11A and 11B determine whether or not the CPU 11A, B is the mutual authentication start side in the previous shared key information acquisition process (step S22).
In the case of the IC chip 1A, since it is a mutual authentication start side (step S22: YES), the CPU 11A of the IC chip 1A reads the parameter corresponding to IDi (in this case, VAKi) from the area X of the memory 12, and Is output to the IC chip 1B (step S23). The output parameter VAKi is transmitted to the communication device 2B via the network 10 by the communication device 2A and passed to the IC chip 1B.
Next, when the CPU 11A of the IC chip 1A receives the IDi and the parameter VBKi output from the counterpart IC chip 2B received by the communication device 1A (step S24), the CPU 11A of the memory 12 uses the parameter VBKi as a key. Authentication (Verify) for accessing the area of IDi in area Y is performed (step S25). When the authentication of step S25 is successful (step S26: YES), SKi is read from the area of IDi of the area Y of the memory 12 and output as a session key to the communication device 2A (step S27). Then, 1 is added to i (step S28), and it is determined whether i is n or less (that is, whether all the keys acquired in the shared key information acquisition process are output as session keys) (step S29). When i is n or less (step S29: YES), the CPU 11A determines whether there is a session key request from the communication device 2A (step S30), and when there is a request (step S30: YES). Returning to step S22, processing for outputting the next key data SKi is performed. If no session key is requested from the communication device 2A in step S30, the process returns to step S29. The session key is discarded every predetermined time, for example, and a new key is used.

On the other hand, in the case of the IC chip 1B attached to the communication device 2B of the communication partner of the communication device 2A in step S22, since it is a response side of mutual authentication (step S22: NO), the CPU 11B of the IC chip 1B The parameter VAKi corresponding to IDi output from the counterpart IC chip 1A is received from the communication device 2B (step S31), the parameter corresponding to the received IDi (in this case, VBKi) is read from the area X of the memory 12, and the counterpart Output to the previous IC chip 1A (step S32). The output parameter VBKi is transmitted to the communication device 2A via the network 10 by the communication device 2B, and passed to the IC chip 1A.
Next, the CPU 11B of the IC chip 1B performs authentication for accessing the IDi area in the area Y of the memory 12 using the parameter VAKi received in step S31 as a key (step S33). When the authentication in step S33 is successful (step S34: YES), SKi is read from the area IDi of the area Y of the memory 12 and output as a session key to the communication device 2B (step S35). Then, 1 is added to i (step S28), and it is determined whether i is n or less (step S29). When i is n or less (step S29: YES), the CPU 11B determines whether there is a session key request from the communication device 2B (step S30), and when there is a request (step S30: YES). Returning to step S22, processing for outputting the next key data SKi is performed. If no session key is requested from the communication device 2A in step S30, the process returns to step S29.

If authentication fails in steps S26 and S34, error processing such as sending an error signal indicating that the output of the session key has failed to the communication device 1 is performed (step S36).
In step S29, when i exceeds n (step S29: NO), shared key information acquisition processing is executed.
Note that the CPUs 11A and 11B of the IC chip 1 end the session key output process in response to, for example, an end notification of encryption communication from the communication device 2.

According to the shared key information acquisition process and the session key output process described above, as shown in FIG. 4, the IC chips 1A and 1B generate the shared information by the key exchange process after mutual authentication (L1). Obtained (L2), key data SK1 to SKn, ID1 to IDn, and parameters VAK1 to VAKn and VBK1 to VBKn for managing keys are extracted from the obtained shared information (L3).
Then, the IC chip 1A on the key exchange start side stores the parameters VAK1 to VAKn in the area X of the memory 12, stores the keys SK1 to SKn in the area Y, and uses the parameters VBK1 to VBKn to access the area Y. Set so that key authentication is required. On the other hand, the IC chip 1B on the key exchange response side stores the parameters VBK1 to VBKn in the area X, stores the key data SK1 to SKn in the area Y, and accesses the area Y using the parameters VAK1 to VAKn as a key. Set to require authentication. Thus, the key data and the parameters for managing the keys are stored in the areas X and Y of the memory 12 of each IC chip 1 so as to face the communication partner IC chip 1 (L4). The information that can be exchanged by the key exchange process depends on the length of the public key, and can be, for example, about 256 bytes. On the other hand, since the session key is as short as about 16 bytes, for example, a plurality of sets of key data and parameters can be shared.

  Then, when performing cryptographic communication between the communication devices 2, the IC chip 1A on the mutual authentication start side reads IDi and the parameter VAKi from the region X and outputs them to the IC chip 1B. The IC chip 1B The IDi and VAKi output from the chip 1A are received, authentication for accessing the area corresponding to IDi in the area Y is performed using the parameter VAKi, and key data SKi is obtained (L5). Similarly, the IC chip 1A also receives IDi and the parameter VBKi from the IC chip 1B, performs authentication for accessing the area corresponding to IDi in the area Y using the parameter VBKi, and obtains key data SKi (L5 ). At this time, the access control in each area in the area Y can be performed at a high speed because it is not a verification, that is, a complicated operation but a comparison process.

  Next, each IC chip 1A, 1B outputs the acquired key data SKi as a session key to the corresponding communication device 2 (L6). Each communication device 2 receives the session key output from the IC chips 1A and 1B, and uses this to encrypt / decrypt communication data (L7).

  As described above, according to the present invention, a plurality of keys (session keys) and parameters for managing the keys are extracted from the shared key information acquired by the key exchange protocol using the secret key and the public key, and the extracted plurality of keys are extracted. Is stored in a memory area that requires authentication using parameters received from the communication partner. Thereby, reliable identification and authentication can be realized. In addition, since a plurality of session keys can be obtained from one shared key information without performing encryption processing, the processing time required for key generation is reduced, and the processing efficiency of encryption communication processing is improved. In addition, security can be maintained by storing key data and parameters for managing keys, and generating and managing keys. Even when communicating with a plurality of communication devices, the key and parameter are managed in association with the ID for each communication partner, so that the key can be easily managed, and the device facing the ID can be identified. In addition, a plurality of safer VPN paths can be used simultaneously.

The present invention can be variously modified and applied.
The above embodiment describes the case where the encryption communication key management device is realized by an IC chip. However, the present invention is not limited to this. For example, the encryption communication key management device may be realized by another tamper-resistant device such as an IC card. Good.
In the above description, each IC chip 1 that performs communication performs processing for generating shared key information. However, the present invention is not limited to this. For example, either the authentication start side or the response side performs the processing. In addition, the execution timing is arbitrary.

The system of the present invention can be realized using a normal computer system, not a dedicated system. For example, a program for executing the above-described operation is stored and distributed in a computer-readable recording medium (FD, CD-ROM, DVD, etc.), and the program is installed in the computer to perform the above-described processing. You may comprise the IC chip 1 and the communication apparatus 2 to perform. Further, the program may be stored in a disk device included in a server device on a network such as the Internet and downloaded to a computer.
In addition, when the OS realizes the above functions by sharing the OS or jointly with the OS and the application, etc., only the part other than the OS may be stored and distributed in the medium, or may be downloaded to the computer. Good.

It is a figure which shows the structural example of the communication system containing the encryption communication key management apparatus (IC chip) of embodiment of this invention. It is a flowchart for demonstrating a shared key information acquisition process. It is a flowchart for demonstrating a session key output process. FIG. 2 is a diagram for explaining a processing flow until the communication device receives a session key from the IC chip in the communication system of FIG. 1.

Explanation of symbols

1 IC chip 11 CPU
12 Memory 13 Input / output I / F
2 Communication equipment 21 Control unit 22 Storage unit 23 Communication unit 24 Input / output I / F

Claims (4)

Means for acquiring shared key information by a key exchange protocol using a secret key and a public key between the communication partner device that is the communication partner and the communication partner device ;
Extraction means for extracting a plurality of sets of first and second parameters for managing key data and key data from the shared key information;
Means for storing the key data extracted by the extracting means in a memory area that requires authentication by one of the first and second parameters at the time of access;
It means for the first and the one parameter of the second parameter acquired from the communication partner device, and outputs the other parameters for the communication partner device,
Obtaining means for accessing the memory area using the obtained one parameter and obtaining key data;
Means for outputting the key data obtained by the obtaining means as session key data;
An encryption communication key management device comprising: The encryption communication key management device is realized by an IC chip.
The encryption communication key management apparatus according to claim 1. The other parameter is used for authentication when the key data stored in the memory area of the communication partner encryption communication key management device is accessed by the communication partner encryption communication key management device as the communication partner device. ,
The encryption communication key management apparatus according to claim 1 or 2, characterized by the above. Computer
Means for acquiring shared key information by a key exchange protocol using a secret key and a public key between the communication partner device that is the communication partner and the communication partner device ;
Extraction means for extracting a plurality of first and second parameters for managing key data and key data from the shared key information;
Means for storing the key data extracted by the extracting means in a memory area that requires authentication by one of the first and second parameters at the time of access;
It means for the first and the one parameter of the second parameter acquired from the communication partner device, and outputs the other parameters for the communication partner device,
An acquisition means for accessing the memory area using the acquired one parameter and acquiring key data;
Means for outputting the key data obtained by the obtaining means as session key data;
Program to function as.

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