Distribution server, distribution system, distribution method and program

Abstract

We provide a system that ensures the safety of distributed data even if it falls into the hands of a third party. [Solution] The distribution server includes means for creating converted data by converting distribution data and check data, creating a beacon including a hash value of the check data, dividing the beacon to create a first beacon and a second beacon, creating a distribution package including the converted data and the first beacon, and means for transmitting the distribution package.

Description

[Technical Field]

[0001] The present invention relates to a distribution server, a distribution system, a distribution method, and a program. [Background technology]

[0002] As the use of communication networks expands, security measures against cyber attacks and other threats are becoming increasingly important. In response to this, private companies are using cyber exercises to develop human resources. In typical cyber exercises, a training environment equipped with a high-quality network is prepared, and a management server that manages the content of the cyber exercise often proceeds by sequentially controlling the execution of simulated cyber attacks on the training terminals.

[0003] For effective and practical exercises, it is preferable to conduct cyber exercises in the environment that users normally use, rather than in a simulated environment prepared for the exercise. In this case, cyber exercise data is distributed from the management server to user devices and then conducted. In recent years, mobile and wireless communications have become widespread, so when conducting cyber exercises in user environments, data is distributed via mobile communications, etc. However, in wireless communications environments, data may be stolen during distribution. Cyber ​​exercise data contains malware capable of simulating cyber attacks, which may be stolen and misused if it falls into the hands of a third party. Furthermore, if malware malfunctions in an unintended environment, unexpected damage may occur. When conducting cyber exercises in a wireless communications environment, it is necessary to be able to prevent unintended cyber attacks from being simulated, even when communication with the management server is down and control is impossible.

[0004] Patent Document 1 discloses a decryption device that reduces the risk of data being illegally decrypted using a leaked decryption key when the decryption key for encrypted data may be leaked to the outside during delivery. This decryption device generates a time-limited key by combining the decryption key with time information, verifies the validity of the time-limited key based on the difference between the time added to the key and the current time, and decrypts the data using the decryption key if it is valid. However, even if a system is designed to decrypt a program that executes a simulated cyber attack using such a time-limited decryption key, there is a possibility that the program may be misused or malfunction if it is decrypted using the decryption key within the time limit. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-19120 Summary of the Invention [Problem to be solved by the invention]

[0006] There is a need for a system that can ensure security even if data distributed for cyber exercises is stolen.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a distribution server, a distribution system, a distribution method, and a program that solve the above-mentioned problems. [Means for solving the problem]

[0008] According to one aspect of the present invention, the distribution server includes means for creating converted data by converting distribution data and check data, creating a beacon including a hash value of the check data, dividing the beacon to create a first beacon and a second beacon, creating a distribution package including the converted data and the first beacon, and means for transmitting the distribution package.

[0009] According to one aspect of the present invention, a distribution system comprises the above-mentioned distribution server and a user terminal, wherein the user terminal comprises means for receiving the distribution package, means for storing the second beacon and a restoration key for restoring the converted data, and means for generating the beacon by combining the first beacon included in the distribution package received by the receiving means with the second beacon stored by the storing means, and means for reading out the restoration key stored by the storing means and restoring the converted data using the read restoration key.

[0010] According to one aspect of the present invention, a distribution method includes the steps of creating converted data by converting distribution data and check data, creating a beacon including a hash value of the check data, dividing the beacon to create a first beacon and a second beacon, creating a distribution package including the converted data and the first beacon, and transmitting the distribution package.

[0011] According to one aspect of the present invention, the program causes a computer to perform the steps of creating converted data by converting distribution data and check data, creating a beacon including a hash value of the check data, dividing the beacon to create a first beacon and a second beacon, creating a distribution package including the converted data and the first beacon, and transmitting the distribution package. [Effects of the Invention]

[0012] According to the present invention, safety can be guaranteed even if distributed data is stolen. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram of a cyber training system according to an embodiment. [Figure 2]FIG. 10 is a diagram illustrating an example of the operation of the cyber training system according to the embodiment. [Figure 3A] 10 is a flowchart illustrating an example of a distribution package creation process according to an embodiment. [Figure 3B] FIG. 10 is a diagram illustrating a distribution package creation process according to an embodiment. [Figure 4A] 10 is a flowchart illustrating an example of a distribution package deployment process according to the embodiment. [Figure 4B] FIG. 10 is a diagram illustrating a distribution package deployment process according to an embodiment. [Figure 5] FIG. 2 is a block diagram showing the configuration of a distribution server having a minimum configuration. [Figure 6] 10 is a flowchart illustrating the processing of a distribution server having a minimum configuration. [Figure 7] FIG. 1 is a diagram illustrating an example of a hardware configuration of a cyber training system according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] <Embodiment> A cyber training system according to an embodiment of the present invention will be described below with reference to the drawings. In the drawings used in the following description, the configuration of parts that are not related to the present invention may be omitted or not shown.

[0015] (System Configuration) FIG. 1 is a block diagram of a cyber training system according to an embodiment. As shown in FIG. 1, the cyber exercise system 1 includes a management server 10, a distribution server 20, and user terminals 30a, 30b, and 30c. The management server 10 instructs the distribution server 20 to distribute data used in cyber exercises executed by the user terminals 30a to 30c and instructs the user terminals 30a to 30c to start the cyber exercises. The distribution server 20 encrypts and packages the data used in the cyber exercises and distributes it to the user terminals 30a to 30c. The encrypted and packaged data distributed by the distribution server 20 is called a distribution package, and the data before encryption and packaging is called distribution data. The user terminals 30a to 30c unpackage and decrypt the distribution package distributed from the distribution server 20 and use the distribution data to conduct the cyber exercises. The user terminals 30a to 30c are terminal devices that participants in the cyber exercises normally use for work or other purposes. For example, the user terminals 30a to 30c are mobile terminals such as personal computers (PCs), tablet terminals, and smartphones. The management server 10, the distribution server 20, and the user terminals 30a to 30c are communicably connected via a network NW. The network NW may be a line that has a narrow bandwidth and is prone to unstable communication conditions such as communication delays and interruptions.

[0016] The management server 10 includes an input receiving unit 11, a control unit 12, a display unit 13, a storage unit 14, and a communication unit 15. The input receiving unit 11 is configured to include input devices such as a touch panel and a keyboard, receives operations performed by a user using the input device, generates information according to the operations, and outputs the generated information to the control unit 12. The control unit 12 controls the operation of the management server 10 based on the operations received by the input receiving unit 11. For example, the control unit 12 controls the display of the display unit 13 and the communication using the communication unit 15. The control unit 12 uses the communication unit 15 to issue instructions for distributing distribution packages, send instructions for carrying out cyber exercises, and send and receive secure beacons, which will be described later. The display unit 13 includes a display device such as a liquid crystal display, etc. The display unit 13 displays various information based on instructions from the control unit 12. The storage unit 14 is composed of storage media such as RAM (Random Access Memory), ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), HDD (Hard Disk Drive), and SSD (Solid State Drive), and stores various information. The communication unit 15 is configured using a communication module, and communicates with other devices such as the distribution server 20 and the user terminals 30a to 30c.

[0017] The distribution server 20 includes an input receiving unit 21 , a control unit 22 , a display unit 23 , a storage unit 24 , and a communication unit 25 . The input receiving unit 21 is configured to include input devices such as a touch panel and a keyboard, receives operations performed by the user using the input device, generates information according to the operations, and outputs the generated information to the control unit 22. The control unit 22 controls the operation of the distribution server 20 based on operations received by the input receiving unit 21 and instruction information received from the management server 10. For example, the control unit 22 controls the display of the display unit 23 and controls communications using the communication unit 25. The control unit 22 includes a package creation unit 221. The package creation unit 221 encrypts and packages distribution data to create a distribution package. The package creation unit 221 also creates a secure beacon. The secure beacon is used to check for tampering with the distribution package. The control unit 22 uses the communication unit 25 to transmit the distribution package to the user terminals 30a to 30c. The control unit 22 also uses the communication unit 25 to transmit the secure beacon to the management server 10. The display unit 23 includes a display device such as a liquid crystal display, etc. The display unit 23 displays various information based on instructions from the control unit 22. The storage unit 24 is configured by a storage medium such as a RAM, a ROM, an EEPROM, a HDD, or an SSD, and stores various information. The communication unit 25 is configured using a communication module, and communicates with other devices such as the management server 10 and the user terminals 30a to 30c.

[0018] The user terminal 30a includes an input receiving unit 31a, a control unit 32a, a display unit 33a, a storage unit 34a, and a communication unit 35a. The input receiving unit 31a is configured to include input devices such as a touch panel and a keyboard, receives operations performed by exercise participants using these input devices, generates information according to the operations, and outputs the generated information to the control unit 32a. The control unit 32a controls the operation of the user terminal 30a based on operations received by the input receiving unit 31a and instruction information received from the management server 10. The control unit 32a includes a package management unit 321a, a beacon monitoring unit 322a, and a practice scenario control unit 323a. The package management unit 321a stores, unpacks, and decrypts distribution packages distributed from the distribution server 20. The beacon monitoring unit 322a records the contents of secure beacons distributed from the management server 10 in a log. The beacon monitoring unit 322a also disables the secure beacons recorded in the log in accordance with usage restriction information transmitted from the management server 10 or set by the user. The practice scenario control unit 323a controls the execution of practice scenarios and malware that simulate cyberattacks included in the distribution packages. The practice scenarios include information such as the timing and conditions for executing malware to simulate cyberattacks, and the practice scenario control unit 323a executes the simulated malware based on the practice scenarios. Furthermore, the distributed simulated malware is configured so that it can only be executed by the practice scenario control unit 323a. For example, the simulated malware may be created in a data format that can only be executed by the practice scenario control unit 323a, or may be configured so that when the malware is launched, inter-process communication is performed with the practice scenario control unit 323a and it cannot be executed unless it is authenticated by a predetermined check process.

[0019] The display unit 33a includes a display device such as a liquid crystal display, etc. The display unit 33a displays information based on instructions from the control unit 32a. The storage unit 34a is configured with storage media such as RAM, ROM, EEPROM, HDD, and SSD, and stores various information such as exercise scenarios. The communication unit 35a is configured using a communication module, and communicates with other devices such as the management server 10, the distribution server 20, and the user terminals 30b to 30c.

[0020] The configuration of user terminals 30b and 30c is the same as that of user terminal 30a, and therefore illustrations and explanations thereof are omitted. Hereinafter, when it is not necessary to distinguish between user terminals 30a to 30c, they will be referred to as user terminal 30, and each functional unit will be referred to as input receiving unit 31, control unit 32, package management unit 321, beacon monitoring unit 322, exercise scenario control unit 323, display unit 33, memory unit 34, communication unit 35, etc. While the cyber exercise system 1 in FIG. 1 is configured to include three user terminals, the number of user terminals 30 may be two or less, or four or more. Furthermore, the cyber exercise system 1 may include multiple management servers 10 or distribution servers 20.

[0021] (operation) <Overall processing flow> Next, referring to FIG. 2, the flow of processing in the cyber exercise system 1 will be described, from the creation and distribution of a distribution package to the deployment of the distribution package on the user terminal 30 that has received the distribution package, and the implementation of a cyber exercise. FIG. 2 is a diagram illustrating an example of the operation of the cyber training system according to the embodiment. It is assumed that distribution data is stored in the storage unit 24 of the distribution server 20. The distribution data includes data to be encrypted, such as a practice scenario and malware, as well as data that is not to be encrypted, such as a practice environment creation program that creates a practice environment by, for example, deploying the practice scenario and malware in an appropriate location after expansion and decryption, and a recovery program that restores the operating environment of the user terminal 30 to the same state as before the practice, such as deleting the practice scenario and malware after the practice.

[0022] The administrator of the cyber exercise performs an operation to instruct the creation and distribution of a distribution package. In the management server 10, the input receiving unit 11 receives this operation, and the control unit 12 uses the communication unit 15 to send instruction information instructing the creation and distribution of the distribution package (step S1). For example, the instruction information includes information specifying the contents of the distribution package and the distribution destination. In the distribution server 20, the communication unit 25 receives the instruction information and outputs the received instruction information to the control unit 22. The control unit 22 instructs the distribution package creation unit 221 to create a distribution package. The distribution package creation unit 221 reads the distribution data from the storage unit 24 and creates a distribution package and a secure beacon (step S2). Details of the creation process of the distribution package, etc. will be explained later using Figures 3A and 3B. Once the distribution package and secure beacon have been created, the control unit 22 uses the communication unit 25 to send the distribution package to the specified distribution destination (step S3). In the user terminal 30, the communication unit 35 receives the distribution package, and the control unit 32 records and saves the distribution package in the storage unit 34 (step S4).

[0023] Furthermore, control unit 22 uses communication unit 25 to transmit a secure beacon to management server 10 (step S5). In management server 10, communication unit 15 receives the secure beacon, and control unit 12 stores the secure beacon in storage unit 14 (step S6). The secure beacon is, for example, text data composed of letters and numbers. The order in which the distribution package and the secure beacon are transmitted may be reversed.

[0024] Next, based on instructions from the administrator, the control unit 12 of the management server 10 uses the communication unit 15 to transmit the secure beacon and the usage restriction information to the user terminal 30 (step S7). In the user terminal 30, the communication unit 35 receives the secure beacon and the usage restriction information and outputs them to the beacon monitoring unit 322. The beacon monitoring unit 322 registers the secure beacon in a dedicated log (step S8). For example, if the secure beacon is a 10-digit character string, the beacon monitoring unit 322 records this character string in a dedicated log file, associates it with the previously distributed distribution package, and stores this log file in the storage unit 34. The beacon monitoring unit 322 also stores the usage restriction information in the storage unit 34 and monitors the validity or invalidity of the received secure beacon based on the usage restriction information (step S9). If the expiration condition is met, the beacon monitoring unit 322 performs a process to invalidate the secure beacon. The usage restriction information is, for example, an expiration date. The expiration condition is that the expiration date has passed. The beacon monitoring unit 322 performs a process of disabling the secure beacon when the date and time set as the expiration date has passed. For example, the beacon monitoring unit 322 may perform the disabling process by recording information indicating that the secure beacon has been disabled in a disabling log file separate from the log file in which the disabled secure beacon is registered. Upon receiving a secure beacon, the beacon monitoring unit 322 determines whether the secure beacon is valid or invalid at predetermined time intervals until the secure beacon is disabled, and performs the above-described disabling process if the secure beacon is invalid. Note that, although the usage restriction information is transmitted from the management server 10 to the user terminal 30 here, to avoid the risk of false usage restriction information being transmitted, the usage restriction information may be communicated to the user, etc., of the user terminal 30 by another means, and the usage restriction information may be set for each user terminal 30 when the training environment is constructed.

[0025] Furthermore, when the communication state between the management server 10 and the user terminal 30 is poor or for the purpose of ensuring higher security, the management server 10 may not transmit a secure beacon or the like to the user terminal 30, but may instead verbally communicate the secure beacon and usage restriction information to the user of the user terminal 30 via telephone or the like. In this case, the user inputs the transmitted secure beacon and usage restriction information into the user terminal 30. The input receiving unit 31 receives this input and outputs the input secure beacon and usage restriction information to the beacon monitoring unit 322. Upon receiving the secure beacon and usage restriction information, the beacon monitoring unit 322 registers the secure beacon in a log and stores the usage restriction information in the storage unit 34. The beacon monitoring unit 322 then monitors whether the secure beacon is valid until it is invalidated, and performs the above-described process of invalidating the secure beacon if the invalidation condition is met. In this case, the usage restriction information may be a limit on the number of times it can be used. The limit number is the number of times the user attempts to input the orally communicated secure beacon into the user terminal 30 (the number of times the beacon monitoring unit 322 registers the secure beacon in the log). If the user attempts to input the secure beacon multiple times, it is determined that some kind of fraud is suspected, and a limit is placed on the number of input operations. The invalidation condition in this case is that the number of input operations exceeds the limit number.

[0026] Next, based on an instruction from the administrator, the control unit 12 of the management server 10 uses the communication unit 15 to send instruction information to the user terminal 30 instructing the start of a cyber exercise (step S10). In the user terminal 30, the communication unit 35 receives the instruction information to start the cyber exercise, and the control unit 32 outputs to the display unit 33 that an instruction to start the cyber exercise has been received. The user performs an operation on the user terminal 30 to instruct the deployment of the package saved in step S4. The input receiving unit 31 receives this operation and notifies the control unit 32 that the operation to instruct the package deployment has been received. The control unit 32 instructs the package management unit 321 to deploy the distribution package. The package management unit 321 reads the distribution package from the storage unit 34 and deploys and decrypts the distribution package (step S11). Details of the distribution package deployment process will be described later with reference to FIGS. 4A and 4B. Once the distribution package is deployed, the user performs an operation on the user terminal 30 to instruct the execution of a cyber exercise. When the input receiving unit 31 receives this operation, the exercise scenario control unit 323 reads out the exercise scenario from the storage unit 34 and executes the exercise scenario, thereby executing the cyber exercise (step S12). In the above explanation, the cyber exercise is initiated upon receipt of instruction information instructing the start of the cyber exercise, which was sent in step S10. However, instead, the cyber exercise may be initiated upon receipt of a secure beacon by the user terminal 30 in step S8.

[0027] <Creating a distribution package> Next, the process of creating a distribution package and a secure beacon in step S2 will be described with reference to FIGS. 3A and 3B. FIG. 3A is a flowchart showing an example of the distribution package creation process. First, the package creation unit 221 of the distribution server 20 encrypts the distribution data to be encrypted among the distribution data (step S21). Details of the encryption process are shown in S21 of FIG. 3B. The package creation unit 221 reads the distribution data to be encrypted D211, the distribution data not to be encrypted D212, and the operating condition data D213 from the storage unit 34. The distribution data to be encrypted D211 is malware that executes training scenarios and simulated cyber attacks. These data are encrypted because they are highly dangerous. The distribution data not to be encrypted D212 is a training environment creation program and a recovery program, and these are not encrypted. The operating condition data D213 is an arbitrary value used for tampering checks. The operating condition data D213 is pre-registered in the storage unit 24 and can be changed at any time. The package creation unit 221 encrypts the distribution data to be encrypted D211 and the operating condition data D213 together to create encrypted distribution data D214 (S211). An encryption key (e.g., a public key) used for encryption is distributed to the distribution server 20 by secure means and is stored in advance in the storage unit 24. In addition, a decryption key (e.g., a private key) used to decrypt the encrypted distribution data D214 is distributed in advance to the user terminal 30 via a path other than the network NW, from the perspective of ensuring security, and is stored in the storage unit 34 of the user terminal 30.

[0028] Next, the package creation unit 221 creates a secure beacon (step S22). S22 in FIG. 3B shows details of the secure beacon creation process. The package creation unit 221 calculates a hash value D221 of the operating condition data D213. The hash value D221 is set as a parameter to detect tampering with the distribution data. The package creation unit 221 also encrypts the hash value D221 using an AES encryption key D223 to calculate a beacon D224 (S222). The AES encryption key D223 is stored in advance in the storage unit 24. Next, the package creation unit 221 divides the beacon D224 to calculate a beacon A (D225) and a beacon B (D226) (S223). The divided beacon A (D225) is stored in the distribution package, and beacon B (D226) is transmitted to the management server as the secure beacon described in FIG. 2.

[0029] Next, the package creation unit 221 creates a distribution package (step S23). Details of the distribution package creation process are shown in S23 of FIG. 3B. The package creation unit 221 packages the encrypted distribution data D214, the AES encryption key D223, the beacon A (D225), and the non-encrypted distribution data D212 into a single file. For example, the package creation unit 221 may archive these files in tar format, or may further compress them and archive them in tar.gz format. The archived file is the distribution package D231. The distribution package D231 is transmitted to the user terminal 30 by the distribution server 20.

[0030] <Extracting the distribution package> Next, the distribution package unpacking process in step S11 will be described with reference to Figures 4A and 4B. Figure 4A is a flowchart showing an example of the distribution package unpacking process. As a premise, the storage unit 34 stores a distribution package D231 and a beacon B (D226) (secure beacon). When the user performs an operation to instruct the unpacking of the distribution package, the beacon monitoring unit 322 acquires from the storage unit 34 a log in which the secure beacon is registered (step S111) and determines whether the secure beacon is within the usage limit (step S112). For example, if the invalidation log file contains information indicating that the secure beacon has been invalidated, the beacon monitoring unit 322 determines that the usage limit has been exceeded. Otherwise (for example, if the log contains an expiration date in the future), the beacon monitoring unit 322 determines that the secure beacon is within the usage limit. The beacon monitoring unit 322 notifies the control unit 32 of this determination result. If the usage limit is not met (step S112; No), the control unit 32 displays an error message (step S119). For example, the control unit 32 outputs a message such as "The expiration date has passed. The distribution package cannot be unpacked" to the display unit 33. In this case, the flowchart of FIG. 4A ends.

[0031] If the usage is within the restrictions (step S112; Yes), the control unit 32 instructs the package management unit 321 to unpack the distribution package. Based on this instruction, the package management unit 321 executes the following process.

[0032] The package management unit 321 reads out the distribution package D231 from the storage unit 34 and unpacks it (step S113). Details of the unpacking process are shown in S113 of Figure 4B. When the distribution package D231 is unpacked (S1131), the encrypted distribution data D214, the AES encryption key D223, the beacon A (D225), and the non-encrypted distribution data D212 are output.

[0033] Next, the package management unit 321 decrypts the beacon D224 (step S114). Details of the beacon decryption process are shown in S114 of FIG. 4B. The package management unit 321 generates the beacon D224 by combining the beacon A (D225) obtained by decompression with the beacon B (D226) stored in the storage unit 34 (S1141). The package management unit 321 decrypts the generated beacon D224 using the AES encryption key D223 obtained by decompression (S1142). As a result of this decryption, the operating condition hash value D221 is output.

[0034] Next, the package management unit 321 decrypts the encrypted distribution data (step S115). Details of the encrypted distribution data decryption process are shown in S115 of FIG. 4B. The package management unit 321 reads out a decryption key (e.g., a private key) that has been stored in advance in the storage unit 34, and decrypts the encrypted distribution data D214 obtained by unpacking the distribution package with the read decryption key (S1151). This decryption results in the encryption target distribution data D211 and operating condition data D213.

[0035] Next, the package management unit 321 checks whether the distribution data has been tampered with (step S116). Details of the tampering check are shown in S116 of FIG. 4B. The package management unit 321 calculates a hash value D221-2 based on the operating condition data D213 obtained by decrypting the encrypted distribution data D214, in the same manner as the package creation unit 221 performed in step S221 (S1161). The package management unit 321 compares the operating condition hash value D221 obtained by decrypting the beacon D224 with the calculated hash value D221-2 (S1162). If the operating condition hash value D221 and the hash value D221-2 match, the package management unit 321 determines that no tampering has occurred. If the operating condition hash value D221 and the hash value D221-2 do not match, the package management unit 321 determines that tampering has occurred. The package management unit 321 notifies the control unit 32 of this determination result.

[0036] If it is determined that there has been no tampering (step S117; Yes), the control unit 32 outputs the distribution data (step S118). For example, the control unit 32 displays a message on the display unit 33 saying "Expansion of the distribution package has been completed," while copying the distribution data to be encrypted D211 and the distribution data not to be encrypted D212 to a predetermined path, etc., and executes the environment creation program included in the distribution data not to be encrypted D212. As a result, the exercise scenario, malware, etc. included in the distribution data to be encrypted D211 are deployed to a predetermined location (path), and an environment in which the exercise scenario can be executed is created.

[0037] If it is determined that tampering has occurred (step S117; No), the control unit 32 performs error processing (step S120). For example, the control unit 32 may delete the encryption target distribution data D211 and the non-encryption target distribution data D212 generated in the processing of steps S113 to S115, while displaying a message that reads "Failed to extract the distribution package" on the display unit 33. In this case, the flowchart of FIG. 4A ends.

[0038] (effect) As described above, according to the cyber training system 1 of this embodiment, data used in the cyber training is distributed separately as a distribution package and a secure beacon. Furthermore, a decryption key (e.g., a private key) required to decrypt malware, etc., included in the distribution package is distributed to the user terminal 30 in advance via a secure path. Therefore, malware, etc., cannot be decrypted unless the distribution package D231, the secure beacon, and the decryption key (e.g., the private key) are all obtained. Therefore, even if the distribution package D231 is stolen during distribution, security can be ensured. Furthermore, the distribution package D231 includes operating condition data D213, and the secure beacon includes a hash value D221 of the operating condition data D213. After the distribution package D231 is decrypted, a hash value is calculated from the operating condition data D213 included in the distribution package D231, and the calculated value is compared with the hash value D221 included in the secure beacon, thereby enabling a tampering check. This allows tampering of the distribution package D231 to be detected and damage caused by data tampering to be prevented. When creating a secure beacon, the hash value D221 is encrypted, the encrypted data is divided, and one part is used to create the secure beacon. The remaining encrypted data and its decryption key (AES encryption key D223) are included in the distribution package D231. Therefore, unless both the distribution package D231 and the secure beacon are obtained, beacon A and beacon B cannot be combined and restored, and a tampering check cannot be performed correctly, thereby ensuring the validity of the tampering check. Furthermore, without a decryption key (e.g., a private key) distributed separately and unrelated to the distribution package D231, the encrypted distribution data D214 cannot be decrypted, making malware recovery difficult and ensuring security. Furthermore, usage restrictions such as an expiration date can be set for beacon B (D226), making malware recovery more difficult and improving security.

[0039] In the actual device configuration, the secure beacon and usage restriction information are transmitted from the management server 10. However, for example, the management server 10 may transmit instruction information instructing the distribution server 20 to transmit a secure beacon, etc., and the distribution server 20, upon receiving the instruction information, may transmit the secure beacon and usage restriction information to the user terminal 30. In the actual device configuration, the encrypted distribution data D211, etc., is encrypted to create the encrypted distribution data D214. However, instead of or in addition to this, to increase the difficulty of decryption if the distribution package is stolen, for example, the target data (e.g., the encrypted distribution data D214 or the encrypted distribution data D211) may be partially or entirely converted (bit-substituted), and information indicating how the data was modified may be included in the secure beacon. Then, when the package is deployed, information indicating how the modification was made may be extracted from the secure beacon, and the converted data may be modified based on the extracted information to restore the data to its pre-bit-substitution state. The information indicating how the modification was made from the secure beacon is an example of a restoration key. Furthermore, a decryption key (for example, a private key) for decrypting the encrypted distribution data D214 is an example of a restoration key.

[0040] Furthermore, to conduct effective cyber exercises, it is desirable to conduct cyber exercises in the environment normally used by participants, rather than in a pre-prepared simulated exercise environment. However, in recent years, network environments that are not necessarily of high quality, such as wireless and mobile communications, have become more prevalent, posing a risk of data theft during distribution. When conducting cyber exercises in a wireless communication environment, even if communication with the management server 10 that controls the exercise is lost and control becomes impossible, it is necessary to be able to control malware so that it does not perform unintended operations. As described above, according to this embodiment, malware restoration is difficult and the restoration period is limited, thereby limiting the opportunities for malware to perform unintended operations. Furthermore, even if malware can be restored, a mechanism is in place that prevents simulated attacks by malware from being performed by anyone other than the exercise scenario control unit 323, thereby reducing the possibility of malware performing unintended operations in an unintended environment.

[0041] (Minimum configuration) FIG. 5 is a block diagram showing the configuration of a distribution server having a minimum configuration. The distribution server 40 includes a package creation unit 41 and a transmission unit 42 . The package creation means 41 creates converted data (e.g., encrypted data, bit-substituted data, or data obtained by converting the original data through both encryption and bit substitution) by converting the distribution data and the check data, and a beacon including a hash value of the check data, divides the beacon to create a first beacon and a second beacon, and creates a distribution package including the converted data and the first beacon. The transmission means 42 transmits the distribution package created by the package creation means 41.

[0042] FIG. 6 is a flowchart showing the processing of a distribution server having a minimum configuration. The package creation means 41 creates converted data (encrypted distribution data D214) by converting the distribution data (distribution data to be encrypted D211) and the check data (operation condition data D213) (step S31). The package creation means 41 creates an encrypted beacon (D224) including a hash value of the check data (operation condition hash value D221) (step S32). The package creation means 41 divides the beacon (D224) (step S33) to create a first beacon (D225) and a second beacon (D226). The package creation means 41 creates a distribution package (D231) including the converted data (D214), the first beacon (D225), and a decryption key (AES encryption key D223) for decrypting the encrypted beacon (step S34). The transmission means 42 transmits the distribution package (step S35).

[0043] FIG. 7 is a diagram illustrating an example of a hardware configuration of the cyber training system according to the embodiment. The computer 900 is, for example, a PC (Personal Computer) or a server terminal device, and includes a CPU 901, a main memory device 902, an auxiliary memory device 903, an input / output interface 904, and a communication interface 905. The management server 10, the distribution server 20, and the user terminal 30 described above are implemented in the computer 900. The above-described processes are stored in the auxiliary memory device 903 in the form of a program. The CPU 901 reads the program from the auxiliary memory device 903, loads it into the main memory device 902, and executes the above-described processes in accordance with the program. The CPU 901 also allocates a memory area in the main memory device 902 in accordance with the program. The CPU 901 also allocates a memory area in the auxiliary memory device 903 for storing data being processed in accordance with the program.

[0044] In at least one embodiment, the auxiliary storage device 903 is an example of a non-transitory tangible medium. Other examples of non-transitory tangible media include a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, and a semiconductor memory connected via the input / output interface 904. Furthermore, when this program is distributed to the computer 900 via a communication line, the computer 900 that receives the program may load the program into the main storage device 902 and execute the above-described processing. The program may also be for realizing part of the above-described functions. Furthermore, the program may be a so-called differential file (differential program) that realizes the above-described functions in combination with another program already stored in the auxiliary storage device 903.

[0045] Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design modifications can be made without departing from the spirit of the present invention. Furthermore, one aspect of the present invention can be modified in various ways within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Furthermore, configurations in which elements described in the above embodiments and variations are substituted with elements that achieve the same effect are also included.

[0046] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes.

[0047] (Appendix 1) A distribution server comprising: means for creating converted data by converting distribution data and check data; creating a beacon including a hash value of the check data; dividing the beacon to create a first beacon and a second beacon; and creating a distribution package including the converted data and the first beacon; and means for transmitting the distribution package.

[0048] (Appendix 2) 2. The distribution server according to claim 1, wherein the transmitting means transmits the second beacon separately from the distribution package.

[0049] (Appendix 3) The distribution server according to claim 1 or 2, wherein the means for creating the distribution package creates the distribution package including a decryption key for decrypting the encrypted beacon, the converted data, and the first beacon.

[0050] (Appendix 4) 4. The distribution server according to claim 1, wherein an expiration date is set for the second beacon.

[0051] (Appendix 5) 5. The distribution server according to claim 1, wherein the distribution data includes malware.

[0052] (Appendix 6) A distribution system comprising: a distribution server according to any one of Supplementary Note 1 to Supplementary Note 5; and a user terminal, wherein the user terminal comprises: means for receiving the distribution package; means for storing the second beacon and a restoration key for restoring the converted data; and means for generating the beacon by combining the first beacon included in the distribution package received by the receiving means with the second beacon stored in the storing means, and means for reading out the restoration key stored in the storing means and restoring the converted data using the read restoration key.

[0053] (Appendix 7) The distribution system described in Appendix 6, wherein the restoration means extracts the check data from the converted data after restoration, calculates a hash value, and compares the calculated hash value with the hash value included in the beacon to determine whether the distribution package has been tampered with.

[0054] (Appendix 8) The distribution system of claim 6 or 7, wherein the user terminal further comprises a means for determining whether the second beacon is valid based on a predetermined expiration condition, and when the determining means determines that the second beacon is not valid, the restoring means does not restore the converted data.

[0055] (Appendix 9) A distribution method comprising the steps of: creating converted data by converting distribution data and check data; creating a beacon including a hash value of the check data; dividing the beacon to create a first beacon and a second beacon; creating a distribution package including the converted data and the first beacon; and transmitting the distribution package.

[0056] (Appendix 10) A program that causes a computer to execute the steps of: creating converted data by converting distribution data and check data; creating a beacon including a hash value of the check data; dividing the beacon to create a first beacon and a second beacon; creating a distribution package including the converted data and the first beacon; and transmitting the distribution package. [Explanation of symbols]

[0057] 1. Cyber ​​Training System 10. Management Server 11 Input reception section 12 Control section 13...Display section 14...Storage section 15. Communications Department 20 Distribution Server 21 Input reception section 22 Control unit 221···Package Creation Department 221 23...Display section 24...Storage section 25. Communications Department 30, 30a, 30b, 30c...User terminal 31, 31a... Input reception section 32, 32a..., control unit 321, 321a···Package Management Department 322, 322a···Beacon Monitoring Unit 323,323a···Exercise scenario control section 33,33a...Display section 34,34a...Storage section 35,35a...Communication Department 900···Computer 901 CPU 902...Main memory 903...Auxiliary storage device 904 Input / Output Interface 905···Communication Interface

Claims

1. means for generating converted data by converting distribution data and check data, generating a beacon including a hash value of the check data, dividing the beacon to generate a first beacon and a second beacon, and generating a distribution package including the converted data and the first beacon; means for transmitting the distribution package; A distribution server comprising:

2. the transmitting means transmits the second beacon separately from the distribution package. The distribution server of claim 1 .

3. the means for creating the distribution package creates the distribution package including a decryption key for decrypting the encrypted beacon, the converted data, and the first beacon.

3. The distribution server according to claim 1.

4. An expiration date is set for the second beacon.

3. The distribution server according to claim 1.

5. The distribution data includes malware.

3. The distribution server according to claim 1.

6. a distribution server according to claim 1 or claim 2; a user terminal; The user terminal means for receiving the distribution package; a means for storing the second beacon and a restoration key for restoring the converted data; means for generating the beacon by combining the first beacon included in the distribution package received by the means for receiving and the second beacon stored in the means for storing, and for reading out the restoration key stored in the means for storing and restoring the converted data using the restoration key that has been read out; A distribution system comprising:

7. the restoring means extracts the check data from the restored converted data, calculates a hash value, and compares the calculated hash value with the hash value included in the beacon to determine whether the distribution package has been tampered with. The distribution system of claim 6.

8. The user terminal means for determining whether the second beacon is valid based on a predetermined expiration condition; Furthermore, When the determining means determines that the second beacon is not valid, the restoring means does not restore the converted data; The distribution system of claim 6.

9. creating converted data by converting the distribution data and the check data; creating a beacon including a hash value of the check data; Dividing the beacon to generate a first beacon and a second beacon; creating a distribution package including the transformed data and the first beacon; transmitting the distribution package; A distribution method having:

10. On the computer, creating converted data by converting the distribution data and the check data; creating a beacon including a hash value of the check data; Dividing the beacon to generate a first beacon and a second beacon; creating a distribution package including the transformed data and the first beacon; transmitting the distribution package; A program that executes the following.

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