Cryptographic communication path monitoring system, monitoring method

Abstract

To provide a cryptographic communication path monitoring system and a common key processing system, capable of improving credibility of communication by providing a monitoring device capable of detecting an intercept condition by monitoring a communication condition.SOLUTION: A first key sharing module is configured to output a common key, and a first cryptographic module of a first base is configured to encrypt plaintext data using the common key and to output encrypted data. A first transmission system is configured to transmit the encrypted data from the first base to a second cryptographic module of a second base. A second transmission system is configured to transmit the common key from the first key sharing module to a second key sharing module of the second base. In the first transmission system, it is configured to receive, in a predetermined optional period, at least transmission condition data from the first base and reception condition data from the second base and to perform matching between the transmission condition data and the reception condition data.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a monitoring system and a monitoring method for an encrypted communication path having high security performance in a communication system, and also extends to a common key processing system.

Background Art

[0002] There is an encrypted communication system that performs encrypted communication using a device common key. This encrypted communication system is configured to transmit encrypted data from a source base A (which may also be referred to as a user's device A) to a destination base B (which may also be referred to as a user's device B). The encrypted data is such that plaintext data is encrypted with a common key (which may also be referred to as an encryption key, a random number key, or a shared key).

[0003] The above common key is generated at a base C (which may also be referred to as a base station C). The base C is provided with a common key generation device and a key distribution device, and transmits the common key to the base A. In this case, the common key is sent from the base C to the base A via a general line (the Internet). Furthermore, the base C transmits the common key to a base D (which may also be referred to as a base station D) via a normal line (for example, a telephone line).

[0004] When the base station D receives the common key, it transmits this common key to the base B via a general line (the Internet). As a result, the base B can decrypt the received encrypted data with the common key in the encryption module.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, encrypted communication has become increasingly important, and there is a growing demand for further encryption of transmitted and received data.

[0007] Therefore, an object of the present invention is to provide a monitoring system for an encrypted communication path and a common key processing system that can improve the reliability of communication by providing a monitoring device capable of detecting eavesdropping situations by monitoring communication situations. Another object is to make it difficult to prevent key eavesdropping by devising a method or means for creating and distributing keys for converting plaintext data into encrypted data and for converting encrypted data into plaintext data, and to provide a monitoring system and a monitoring method for an encrypted communication path.

Means for Solving the Problems

[0008] According to one embodiment, a first key sharing module that outputs a common key, a first encryption module at a first site that encrypts plaintext data using the common key and outputs encrypted data, a first transmission system that transmits the encrypted data from the first site to a second encryption module at a second site, a second transmission system that transmits the common key from the first key sharing module to a second key sharing module at the second site, and a monitoring device provided in the first transmission system that receives at least transmission status data from the first site and reception status data from the second site during a preset arbitrary period and performs a comparison between the transmission information data and the reception status data, and provides a monitoring system for an encrypted communication path.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2A

Figure 2B

Figure 3A

Figure 3B

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0010] The following embodiments will be described with reference to the drawings. Figure 1 shows an embodiment of the present invention. Now, let A be the first base point as the transmission source (which may also be referred to as the user's device A), and B be the second base point B as the transmission destination (which may also be referred to as the user's device B). It should be noted that base point A and base point B can communicate with each other. Here, the first base point A will be described as the transmission source and the second base point B as the transmission destination.

[0011] The first site A includes a processor 100, an encryption module 101, and a key sharing module 102. The second site B includes a processor 200, an encryption module 201, and a key sharing module 202. Note that when the key sharing module 102 uses a mobile phone network (hereinafter referred to as the "mobile network") for the distribution of the common key, it may be referred to as a cellular module.

[0012] At the first site A, based on the control of the processor 100, the plaintext data 131 and the common key 132 are supplied to the encryption module 101. The encryption module 101 encrypts the plaintext data 131 using the common key 132. The plaintext data 131 is read from a storage device (not shown).

[0013] The encrypted encrypted data 302 is transmitted to the encryption module 201 of the second site B via the first transmission system 300. The encrypted data 302 is, for example, data formed by performing an exclusive logical sum (hereinafter referred to as "XOR") operation on the plaintext data 131 and the common key 132. The first transmission system 300 is, for example, the Internet.

[0014] On the other hand, the common key 132 is transmitted from the key sharing module 102 to the key sharing module 202 of the second site B via the second transmission system 400. The second transmission system 400 is, for example, a mobile network.

[0015] At the second site B, the plaintext data 131 is decrypted as follows. The key sharing module 202 receives the common key 132 and supplies this common key 132 to the encryption module 201. The encryption module 201 decrypts the encrypted data 302 using the common key 132. The decrypted plaintext data 131 is stored in the storage device based on the control of the processor 200.

[0016] The above description has explained that the plaintext data 131 at site A is encrypted and transmitted to site B. However, when the plaintext data at site B is encrypted and transmitted from site B to site A, the above description is equally applicable.

[0017] According to the above embodiment, the encryption module 101 and the key sharing module 102 at site A are integrated, and the arrangements of both are not separated distantly. That is, the encryption module 101 and the key sharing module 102 are arranged in one management area (which may also be referred to as a private area).

[0018] For example, the encryption module 101 and the key sharing module 102 are stored, for example, inside a hospital, inside a factory, or inside a building owned by user A, or on a floor, or inside a single box, or on a single circuit board. The same can be said for site B.

[0019] Therefore, the common key transmission path 105 at site A is under the management of the users at site A. That is, the common key transmission path 105 exists inside a box, a management area, or a building 106 owned by the users at site A. Thus, the common key at site A is less likely to be stolen, and the security of the system is ensured. The same can be said for site B. That is, the transmission path 205 of the common key 132 exists inside a box, a management area, or a building 206 owned by the users at site B, the security of the common key at site B is high, and the security of the system is ensured.

[0020] In the above embodiment, it was explained that the common key is stored in a storage device (not shown). Next, an explanation will be given below regarding what data is used and where the common key is created. In this system, since the key sharing module and the encryption module are integrated as described above, the method of obtaining the common key also becomes an important technical issue. That is, the common key distribution system, the method of creating and distributing the common key, or the means of creating and distributing are also important.

[0021] FIG. 2A and FIG. 2B are diagrams for explaining how to establish a second transmission system 400 for distributing a common key in order to realize key sharing when communicating encrypted data between base point A and base point B. In this example, the first transmission system 300 is described by taking an IP network as an example, and the second transmission system 400 is described by taking a mobile network as an example. Also, for the sake of simplicity of explanation, an example of performing communication from base point A to base point B is described. It is obvious that when communicating from base point B to base point A, the reverse procedure is applicable.

[0022] First, base point A needs to establish communication of the second transmission system 400 for transmitting the common key 132 to base point B. Therefore, base point A needs to obtain the phone number of base point B directly or indirectly. As this method, there are two patterns: method 1 of obtaining the phone number of base point B from a path management center (server 600) that holds a database (DB) associating an Internet protocol (IP) address and a phone number as shown in FIG. 2A, and method 2 of directly communicating between base points A and B via IP to obtain the phone number of base point B as shown in FIG. 2B.

[0023] Note that in method 1, base point A does not necessarily obtain the phone number of base point B itself. Key sharing can also be realized by base point A presenting the IP address of base point B and requesting the server 600 to transmit the common key 132. That is, it is also possible for base point A to indirectly know the phone number of base point B via the server 600. In this case, base point A and the server 600, and the server 600 and base point B are connected via a mobile network, and base points A and B are connected via the mobile network via the server 600.

[0024] The first method 1 (example of FIG. 2A) is that the path management center (server 600) manages by associating an "IP address" and a "phone number, etc.". Here, base point A (the source) first presents the "IP address" of base point B (the destination) to the path management center (server 600) and requests the "phone number" of base point B (the destination) 601, and obtains the "phone number (phone number associated with the IP address)" of base point B 602. (At this time, base point A recognizes the IP address of base point B).

[0025] In the case where Site A requests the server 600 to transmit the common key 132 to Site B, Site A does not necessarily have to obtain the phone number of Site B itself. In this case, 601 becomes a request to notify the server 600 of the connection destination (Site B) on the mobile network, and 602 becomes a response to notify the success or failure thereof. Note that the communication of 602 can also be omitted.

[0026] Note that the route management center can also be arranged on the cloud.

[0027] The second method 2 (example in Fig. 2B) is a method in which Site A (the source) communicates directly with Site B (the destination) (at this time, Site A recognizes the IP address of Site B), Site A requests the phone number of Site B 601, and obtains the phone number of Site B 602. Note that conversely, it is also possible to adopt a method in which Site A (the source) communicates directly with Site B (the destination) (at this time, Site A recognizes the IP address of Site B), Site A notifies Site B of the phone number of Site A 601, and Site B notifies a response of permission 602. In this case, the communication connection of the second transmission system 400 is started from Site B. Also in this case, the communication of 602 can be omitted.

[0028] Through the above-described communication, Site A directly or indirectly knows the phone number of Site B.

[0029] Next, there are two methods for key generation and distribution: Method 3 in which the key distribution center (server 600) generates and distributes the type of the common key or the common key itself, and Method 4 in which Site A generates and distributes the type of the common key or the common key itself (hereinafter, including the type of the common key, it is referred to as the common key). Since Method 4 for generating and distributing the common key at Site A only requires the sharing of the common key, it is also possible to adopt Method 5 in which Site B generates and distributes the common key by entrusting Site A to generate and distribute the common key to Site B. Note that the key distribution center can also be arranged on the cloud.

[0030] For example, there are four possible combinations of the connection method of the second transmission system 400 and the key generation and distribution method.

[0031] In the combination where the connection method of the second transmission system 400 is Method 1 where there is a route management center and the key generation and distribution method is Method 3 by a key distribution center (the type in FIG. 2A), the route management center and the key distribution center can be combined into one. Thereby, it becomes easier to coordinate the route management and the common key management.

[0032] In the combination where the connection method of the second transmission system 400 is Method 2 by inquiry between bases and the key generation and distribution method is Method 4 of generation and distribution at the bases (the type in FIG. 2B), the route management center becomes unnecessary. This will be further described specifically.

[0033] FIG. 2A shows an example where there is a database in which IP addresses and telephone numbers are linked. The same parts as in FIG. 1 are denoted by the same reference numerals as in FIG. 1 and will be described.

[0034] Now, assume that the first transmission system 300 is the Internet and the second transmission system 400 is a mobile network. And assume that a database DB linking the IP addresses of each base and the telephone number of the base is stored in the server 600.

[0035] When Site A wants to communicate with Site B, it requests Server 600 for the phone number of Site B (Request 601). Then, Server 600 responds to Site A with a phone number response (Response 602) according to the request. Thus, Site A can obtain the phone number of Site B. And, for example, Site A generates a common key. Further, Site A encrypts the plaintext data using the common key and sends the encrypted data towards Site B via the Internet. Also, Site A makes a call to the phone number of Site B and secures a communication path with Site B through the mobile network. Then, Site A uses this mobile network to send the common key to Site B. On the other hand, Site B receives the common key from the mobile network and decrypts the encrypted data received via the Internet using this common key. At this time, at Site B, it is also possible to assign a code for matching with the received encrypted data, the common key, or both of these data so that the encrypted data and the common key can be associated with each other.

[0036] Figure 2B shows an example where Site A directly requests the phone number of Site B (Request 601) from Site B via the first transmission path 300 (Internet). Site B makes a phone number response (Response 602) according to the request. Thus, Site A can obtain the phone number of Site B. After that, as described above, Site A can create the common key by itself or entrust it to an external party (such as a key generation device (not shown), Server 600, etc.). For example, it is also possible to request Site B to generate the common key. The above example is an example where Site A obtains the phone number of Site B, but when Site B obtains the phone number of Site A, there is a similar form. That is, there are a type of obtaining the phone number from Server 600 and a direct type of obtaining the phone number directly from the party to communicate with (i.e., Site A).

[0037] As described above, in addition to obtaining the phone number of the other party, Site A or Site B needs to generate or distribute a common key.

[0038] There are various forms for where to generate the common key 132. First, Site A will be explained.

[0039] As shown in FIG. 3A, after establishing communication with the server 600 via the second path 400, the base A can entrust the server 600 to generate the common key 132. Then, the server 600 can be instructed to deliver the common key 132 to the base A via the second path 400. The base A can transmit the common key 132 received from the server 600 to the base B via the second path 400. As another method, the server 600 can be instructed to deliver the common key 132 to both the base A and the base B via the second path 400. As another example, there is the example shown in FIG. 3B.

[0040] That is, in FIG. 3B, the common key 132 is created by the base A. After the base A obtains the phone number of the base B and then establishes communication via the second path 400, the common key 132 is delivered to the base B via the second path. Note that the common key 132 may be received by the base A after being generated by entrusting the server 600 instead of being created at the base A. After obtaining the phone number of the base B and then establishing communication via the second path 400, the common key 132 is delivered to the base B via the second path.

[0041] In the example of FIG. 3B above, the common key 132 is created by, for example, the key sharing module 102 of the base A. However, the base A can also entrust the base B to create the common key 132 using the Internet, mobile network, etc. Then, the base B can generate the common key 132 by itself, or the base B can also entrust the server 600 to generate the common key 132. That is, there are many possible examples of where to generate the common key 132.

[0042] As described above, bases A and B of the present system may include means as described below. That is, bases A and B may include means for generating a common key. Alternatively, bases A and B may include means for entrusting an external server to generate the common key. Furthermore, bases A and B can also entrust the generation of the common key to another base different from themselves. Also, these generation sources may be made changeable based on time zones or conditions, and this change function can be easily provided within the system. Thereby, the generation source of the common key is seemingly randomized, and the security performance of the system can be enhanced.

[0043] Figure 4 shows a configuration example with further improved security performance of the present system. For example, it is an example where base F acts as an attacker and performs a man-in-the-middle attack. When an attacker (base F) infiltrates between bases A and B on the first transmission path 300 (for example, the Internet) and the attacker (base F) also joins the service of the second transmission system 400 (for example, the mobile network) in which bases A and B are participating, there is a risk that the common key shared with the encrypted data will be eavesdropped. The attacker (base F) may impersonate base B to base A and impersonate base A to base B, first eavesdrop on the common key, and there is a possibility of decrypting the encrypted data with the eavesdropped common key. However, in this embodiment, such eavesdropping can be prevented.

[0044] Now, assume that a fake base F (note: here it is assumed to be a fake base F, but it may not be fake depending on the determination result) infiltrates (is placed) into the first transmission system 300 (Internet) and / or the second transmission system 400 (mobile network) and performs eavesdropping (relaying). Assume that the fake base F also has an encryption module F01 and a key sharing module F02. This base F has the possibility of obtaining the common key on the mobile network in the second transmission system 400, for example, and eavesdropping on the encrypted data on the first transmission system 300.

[0045] Therefore, as a countermeasure against such wiretapping, in this system, during any specific period, if base station A and base station B transmit encrypted data and / or a common key, they are configured to output transmission status data to a server (specifically, a monitoring device) 1001 existing in cloud 1000 on the network (for example, the Internet). Also, if encrypted data and / or a common key are received, they are configured to output reception status data to the monitoring device 1001. Note that any specific period (within a predetermined fixed time) can be changed to various periods based on the management of the system management organization, and its frequency can also be changed. Preferably, when the specific period is set immediately after or a few minutes after the data transmission destination (or route) is determined, a large loss of data (the amount of wiretapping) may be reduced. Alternatively, the specific period may be set immediately before the transmission of one file is completed and just before a new file is transmitted, or a few minutes after the transmission of the new file is started.

[0046] Here, the transmission status data and the reception status data represent data that can identify communication. With this configuration, within a predetermined fixed time, the monitoring device 1001 can capture the transmission status data D11, reception status data D12, transmission status data D13, and reception status data D14, and check the match / mismatch status of these status data. Now, organizing the status data confirmed by the monitoring device 1001 results in the following, that is, Confirmation 1... Transmission status data D11 of base station A for a signal from base station A to base station F Confirmation 2... Reception status data D12 of base station F for a signal coming from base station A to base station F Confirmation 3... Transmission status data D13 of base station F for a signal from base station F to base station B Confirmation 4... Reception status data D12 of base station B for a signal coming from base station F to base station B.

[0047] FIG. 5 is an operation explanatory diagram of the monitoring device 1001 shown for explaining the operation during a specific period in the encrypted communication system of FIG. 4.

[0048] For the monitoring device 1001, the above-mentioned transmission status data and reception status data are aggregated within a specific period (T1 - T44). That is, base A transmits communication data to base F at timing T1 and transmits transmission status data D11 to the monitoring device 1001 at timing T2.

[0049] Base F receives the communication data from base A at timing T11 and transmits reception status data D12 to the monitoring device 1001 at timing T12. Also, base F transmits communication data to base B at timing T13 and transmits transmission status data D13 to the monitoring device 1001 at timing T14. Further, base B receives the communication data from base F at timing T21 and transmits reception status data D14 to the monitoring device 1001 at timing T22.

[0050] The monitoring device 1001 receives the previous transmission status data D11 at timing T41, receives the reception status data D12 at timing T42, receives the transmission status data D13 at timing T43, and receives the reception status data D14 at timing T44.

[0051] Judgment J1... The monitoring device 1001 compares D11 and D12 (i.e., performs matching). If D11 = D12, it determines that the communication is normal. When comparing D11 and D12 and they are different, it determines that the communication is abnormal. Note that the status data of D11 and D12 are stored in the memory for a preset setting time. After the setting time has elapsed, this status data is deleted.

[0052] Judgment J2... The monitoring device 1001 compares D13 and D14. If D13 = D14, it determines that the communication is normal. When comparing D13 and D14 and they are different, it determines that the communication is abnormal.

[0053] Judgment J3 The monitoring device 1001 compares "D11 = D12" = "D13 = D14". Here, if "D11 = D12" = "D13 = D14" holds, it determines that there is an abnormality (eavesdropping, that is, a man-in-the-middle attack is being carried out).

[0054] Next, when the situation of "D11 = D12" is different from the situation of "D13 = D14", it is determined that normal communication is being carried out.

[0055] The reason for such determination is that it is obvious that the base A and the next base F form a pair (the transmission status data and the reception status data match), and the base F and the next base B form a pair (the transmission status data and the reception status data match), and within a certain period (a specific period) between the base A and the base F and between the base F and the base A, the communication on the Internet should not be exactly the same in cases other than the man-in-the-middle attack.

[0056] The above determination J3 can be stated as follows. That is, an attack by a man-in-the-middle can be detected by monitoring the communication. All bases are connected to the monitoring device and monitor the communication data. The monitoring device 1001 monitors the information on the transmission status of the transmission destination and the reception status of the reception source in the communication within a predetermined certain period (a specific period). The transmission status and the reception status represent communication data and data that can identify the communication. Here, when the transmission status and the reception status do not match from the pair of the transmission destination and the reception source, either the sender or the receiver is illegal (the attacking side). Therefore, in order to avoid being detected of the man-in-the-middle attack, the attacker may falsify the report of the reception status or the transmission status, but this cannot be executed. Even if falsified, it will be different from the reception and transmission status reported from the bases that are sending and receiving, so the illegality will be revealed at this point. Also, in the case of communication where the transmission status and the reception status match from the pair of the transmission destination and the reception source, and either or both of the transmission status or the reception status also match in another pair, it can be seen that an illegal communication via the base F is being carried out. That is, it can be seen that a man-in-the-middle attack is being carried out at the base F. When the monitoring device 1001 detects the illegality, it can warn the bases involved in the communication, or impose restrictions on the communication such as blocking, to prevent the man-in-the-middle attack. Also, the monitoring device 1001 issues the above warning to the system management organization, etc.

[0057] FIG. 6 is a configuration explanatory diagram of an encrypted communication system showing another embodiment for the embodiment of FIG. 4. The same parts as those in FIG. 4 are denoted by the same reference numerals, and the same description is omitted. The part different from the configuration of FIG. 4 is that hash values are used as transmission status data and reception status data. That is, · HashD11 is used as the transmission status data of base A for the signal from base A to base F · HashD12 is used as the reception status data of base F for the signal from base A to base F · HashD13 is used as the transmission status data of base F for the signal from base F to base B · HashD12 is used as the reception status data of base B for the signal from base F to base B and used as such.

[0058] Also in this embodiment, the determination as to whether an unauthorized act (attack) is being performed on the system is the same as the determination method described in FIG. 5 above. By using hash values, there is an effect that the communication data volume between bases A, F, C and the cloud can be significantly reduced, and the determination and processing can be obtained at high speed. The previous fixed period can also be a short time, and the load on the original encrypted communication becomes small.

[0059] Also in this system, if the transmission status and the reception status do not match from the pair of the transmission destination and the reception source, either the transmitter or the receiver is unauthorized (the attacking side). Also, in the case of communication where the transmission status and the reception status match from the pair of the transmission destination and the reception source, and either or both of the transmission status and the reception status also match in another pair, it can be seen that a man-in-the-middle attack is being carried out. When the monitoring device 1001 detects an unauthorized act, it can warn the base related to the communication, or impose restrictions on the communication such as blocking, to prevent a man-in-the-middle attack. In the above description, for example, base A transmits a common key to base B via the second transmission system 400. The common key at this time is created by any of various methods as described in FIGS. 2A, 2B, 3A, and 3B.

[0060] FIG. 7 is a block configuration diagram schematically showing the interiors of base points A and B. Base points A and B have the same configuration and are formed, for example, on a substrate AB. A processor AB111 can comprehensively control a memory AB112, an encryption module AB101, a key sharing module AB102, a communication circuit AB114, and an external storage device AB113 on the substrate AB. The external storage device AB113 may be arranged in a box together with the substrate AB, or may be connected outside the box.

[0061] According to the above-described encrypted communication system and the monitoring system for an encrypted communication path, even if communication data (encrypted data and / or a common key) is transmitted and received using a relatively open line (transmission system), unauthorized eavesdropping can be immediately detected, providing high security performance.

[0062] FIG. 8 is a diagram showing a basic configuration example of a monitoring device 1001. The monitoring device 1001 includes a memory 1021, a processor 1022, and a clock 1023. Further, the monitoring device 1001 includes a status data acquirer 1024, an eavesdropping location determiner 1025, and a notifier 1026 that acquire data on transmission status and reception status from a route through which a common key is distributed.

[0063] The processor 1022 comprehensively controls the above functional units in the monitoring device 1001. When a specific period predetermined for performing monitoring arrives, the processor 1022 starts a monitoring operation based on time information from the clock 1023. This operation is as described with reference to FIGS. 4, 5, and 6. Note that the time information is not limited to clock counting, and may depend on time information from a time server, and is not limited to this example.

[0064] Note that various examples are possible for the method of setting a specific period. It is possible to set the start time periodically, or set the start time randomly, or transmit a specific synchronization signal, and each base station outputs reception status data and transmission status data based on this synchronization signal. Also, this specific period may be determined by the monitoring device 1001. Further, the specific period may be the period during which a series of communications are started and ended (that is, while the communication session is maintained).

[0065] The transmission status data D11, reception status data D12, transmission status data D13, and reception status data D14 are acquired by the status data acquirer 1024 and are once stored in the memory 1021.

[0066] The eavesdropping location determiner 1025 determines whether there is any fraud as described with reference to FIG. 5. This determination processing program is executed by the processor 1022. If fraud (eavesdropping) is detected, the notifier 1026 is activated, and an alarm signal is notified to the user, system administrator, or each base station. Alternatively, it is notified to a cloud service (for example, a database access service that associates a phone number and an IP address), and the base station F is excluded from the cloud service.

[0067] The concept of the present invention is not limited to the above-described communication system. Among encryption communication systems, there is a system that employs quantum encryption communication. Also in this system, the encrypted data is encrypted with a common key.

[0068] Therefore, even if the distribution route of the common key is a quantum encryption communication network, the present invention is applicable to this system.

[0069] A) The monitoring means in the above-described system of the present invention includes the following features. That is, A1) a first key sharing module that outputs a common key, a first encryption module of the first base station that encrypts plaintext data using the common key and outputs encrypted data, A first transmission system for transmitting the encrypted data from the first base to the second encryption module at the second base; A second transmission system for transmitting the common key from the first key sharing module to the second key sharing module at the second base; A monitoring system for an encrypted communication path, comprising: a monitoring device provided in the first transmission system, which receives at least transmission status data from the first base and reception status data from the second base during a preset arbitrary period, and performs matching between the transmission information data and the reception status data.

[0070] A2) In the above A1, the monitoring device When receiving transmission status data D11 from the first base, receiving reception status data D12 from the second base, receiving transmission status data D13 from the second base, and receiving reception status data D14 from a third base, Comprises a determiner that performs at least matching of D11 = D12, D13 = D14 and matching of "D11 = D12" = "D13 = D14".

[0071] A3) In the above A1, when the monitoring device determines that "D11 = D12" = "D13 = D14" holds, it has at least means for mitigating a man-in-the-middle attack. For example, it comprises a notifier for warning the first base.

[0072] A4) In the above A1, hash values are used as the transmission status data and the reception status data.

[0073] A5) In the above A1, the monitoring device is arranged in the cloud of the Internet.

[0074] A6) In the above A1, the monitoring device is arranged in the cloud of the Internet together with a server. The server stores information on the phone numbers of at least multiple bases and makes this information available for creating the common key.

[0075] A7) In A1 above, the arbitrary period is set immediately after a new route for transmitting the encrypted data is set or a few minutes after transmission of the encrypted data is started on the new route.

[0076] A8) In A1 above, the first base includes a first encryption module and a first key sharing module within a first private area, and the second base includes a second encryption module and a second key sharing module within a second private area. By making it a private area, the transmission path between the key sharing module and the encryption module becomes secure.

[0077] A9) A first key sharing module outputs a common key, the first encryption module of the first base encrypts plaintext data using the common key and outputs encrypted data, a first transmission system transmits the encrypted data from the first base to the second encryption module of the second base, a second transmission system is a method for monitoring an encrypted communication path that transmits the common key from the first key sharing module to the second key sharing module of the second base, In the first transmission system, at an arbitrary period set in advance, at least transmission status data from the first base and reception status data from the second base are received, and the transmission information data and the reception status data are collated. A method for monitoring an encrypted communication path.

[0078] A10) In A9 above, when transmission status data D11 from the first base is received, reception status data D12 from the second base is received, transmission status data D13 from the second base is received, and reception status data D12 from a third base is received, at least a collation of D11 = D12, D13 = D14 and a collation of "D11 = D12" = "D13 = D14" are performed. B) Also, the common key processing system in this system includes the following features.

[0079] B1) A first key sharing module that outputs a common key, A first encryption module at a first site that encrypts plaintext data using the common key and outputs encrypted data, A first transmission system that transmits the encrypted data from the first site to a second encryption module at a second site, In a common key processing system comprising: a second transmission system that transmits the common key from the first key sharing module to a second key sharing module at the second site. A second transmission system (for example, a mobile network) or a path management center arranged on the cloud, A database constructed in the path management center, the database having the IP addresses of the first site and the second site and the telephone numbers corresponding to these IP addresses, At least the first site is provided with means for accessing the database of the path management center and generating at least the common key using the IP address and / or the telephone number.

[0080] B2) In B1) above, the common key is created at the first site. B3) In B1) above, the common key is created as a result of the first site entrusting other nodes or other sites.

[0081] C) Furthermore, the common key processing system in this system includes the following features.

[0082] C1) A first key sharing module that outputs a common key, A first encryption module at a first site that encrypts plaintext data using the common key and outputs encrypted data, A first transmission system that transmits the encrypted data from the first site to a second encryption module at a second site, In a common key processing system comprising: a second transmission system that transmits the common key from the first key sharing module to a second key sharing module at the second site. At least the first base has means for obtaining the telephone number of the second base via the Internet with respect to the second base, and generating at least the common key using this telephone number.

[0083] C2) In C1) above, the common key is created at the first base. C3) In C1) above, the common key is created as a result of the first base entrusting other nodes or other bases.

[0084] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope. Furthermore, in each component of the claims, whether the components are expressed separately, combined, or combined, it is within the scope of the present invention. Also, a plurality of embodiments may be combined, and the embodiments constituted by this combination are also within the scope of the invention.

[0085] Also, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual aspect. Also, when the claims are expressed as control logic, when expressed as a program including instructions for causing a computer to execute, and when expressed as a computer-readable recording medium storing the instructions, the device of the present invention is applied. Also, the names and terms used are not limited, and other expressions are included in the present invention as long as they have substantially the same content and the same gist.

Explanation of Reference Numerals

[0086] A ··· base point, B ··· base point, 100, 200 ··· processors, 101, 201 ··· encryption modules, 102, 202 ··· key sharing modules, 131 ··· plaintext data, 132 ··· common key, 300 ··· first transmission system, 302 ··· encrypted data, 400 ··· second transmission system, 600 ··· server, DB ··· database, F ··· fake base point, 1001 ··· monitoring device.

Claims

1. A first key sharing module that outputs a common key; A first encryption module at a first site that encrypts plaintext data using the common key and outputs encrypted data; A first transmission system that transmits the encrypted data from the first site to a second encryption module at a second site; A second transmission system that transmits the common key from the first key sharing module to a second key sharing module at the second site; A monitoring device that is provided in the first transmission system and receives at least transmission status data from the first site and reception status data from the second site within a preset period, and performs collation between the transmission status data and the reception status data; The monitoring device is: When receiving transmission status data D11 from the first site, receiving reception status data D12 from the second site, receiving transmission status data D13 from the second site, and receiving reception status data D14 from a third site, It includes a determiner that performs at least collation of D11 = D12, D13 = D14 and collation of "D11 = D12" = "D13 = D14"; Furthermore, the monitoring device includes a notifier that warns at least the first site when "D11 = D12" = "D13 = D14" is established in relation to the transmission status data and the reception status data. A monitoring system for an encrypted communication channel.

2. The monitoring system for an encrypted communication channel according to Claim 1, wherein hash values are used as the transmission status data and the reception status data.

3. The monitoring system for an encrypted communication channel according to Claim 1, wherein the monitoring device is arranged in the cloud of the Internet.

4. The monitoring system for an encrypted communication channel according to Claim 1, wherein the monitoring device is arranged in the cloud of the Internet together with a server, and the server stores information on the telephone numbers of at least a plurality of sites and can use this information for creating the common key.

5. The monitoring system for an encrypted communication channel according to Claim 1, wherein the period is set immediately after a new route for transmitting the encrypted data is set or a few minutes after the transmission of the encrypted data starts on the new route.

6. The first base includes a first encryption module and a first key sharing module within a first private area, and the second base includes a second encryption module and a second key sharing module within a second private area. The monitoring system for an encrypted communication path according to claim 1.

7. The first key sharing module outputs a common key. The first encryption module of the first base encrypts the plaintext data using the common key and outputs encrypted data. The first transmission system transmits the encrypted data from the first base to the second encryption module of the second base. A method for monitoring an encrypted communication path, wherein the second transmission system transmits the common key from the first key sharing module to the second key sharing module of the second base. In the first transmission system, at least the transmission status data from the first base and the reception status data from the second base are received within a preset period, and the transmission status data and the reception status data are collated. When collating, when receiving the transmission status data D11 from the first base, the reception status data D12 from the second base, the transmission status data D13 from the second base, and the reception status data D14 from the third base. At least perform the collation of D11 = D12, D13 = D14 and the collation of "D11 = D12" = "D13 = D14". Furthermore, when "D11 = D12" = "D13 = D14" is established in the relationship between the transmission status data and the reception status data, at least issue a warning to the first base. A method for monitoring an encrypted communication path.

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