Intercom system

Abstract

To provide an intercom system capable of ensuring authenticity of a transmission source of a recorded and stored video image, and also ensuring authenticity indicating that the video image has not been tampered with.SOLUTION: An intercom system has an entrance slave unit 1 with a calling function and a conversation function, and a room master unit 2 with a function to respond to calls from the entrance slave unit 1. The entrance slave unit 1 comprises a camera 13 for imaging a person who operates the entrance slave unit 1, and the room master unit 2 comprises a monitor 23 for displaying a video image captured by the camera 13, and also has a management server 3 for storing the captured video image. The entrance slave unit 1 has a private key for digitally signing a video image to be output, and encrypts the video image captured by the camera 13 with the private key and outputs it to the management server 3. The management server 3 stores the received video image in a state where the received video image has been digitally signed with the private key, and has a public key that is paired with the private key to decrypt it. When the stored video image is output, the management server outputs a video image decrypted by using the public key.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an intercom system, and more particularly to an intercom system having a function for storing an image of a caller. [Background technology]

[0002] There is an intercom system that improves security by encrypting the captured image of the caller, such as a visitor who has been called, and sending it from the slave unit to the master unit, thereby preventing others from peeking in. For example, in the intercom system for an apartment building described in Patent Document 1, when the captured image of the camera is output from the slave unit installed at the common entrance, it is encrypted with a different scramble key for each dwelling unit and sent to the master unit. In this way, the image of the visitor can only be correctly decrypted by the master unit of the visitor's home that has been called, and therefore cannot be decrypted and played back by other master units, thereby maintaining high security. On the other hand, in the public key cryptography method for encrypting information to be transmitted, there is a technology that uses a private key and a public key that pairs with it to prevent tampering. This technology uses a private key to digitally sign and encrypt information and transmit it, and then the receiving party decrypts it with the public key to verify that the information has not been tampered with. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-30894 A Summary of the Invention [Problem to be solved by the invention]

[0004] The technology of Patent Document 1 above maintained high security because it prevented others from peeking at the video. However, this technology was not designed to prevent video tampering, so the authenticity of the sender could not be ensured for video that had been recorded and saved. In addition, it was not possible to objectively determine whether the video had been tampered with.

[0005] In view of the above problems, the present invention aims to provide an intercom system that can ensure the authenticity of the sender of recorded and stored video, and can also ensure that the video has not been tampered with. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides an intercom system having a handset with a calling function and a parent unit with a function of responding to calls from the handset, the handset having a camera for capturing an image of the person operating the handset, and the parent unit having a monitor for displaying the image captured by the camera, the handset having a private key for digitally signing and outputting the image, and encrypting the image captured by the camera with the private key and outputting it to a storage means, while having a storage means for storing the image captured by the camera, the storage means storing the received image in an encrypted state, and having a public key for verifying the digital signature made with the private key, and when outputting the stored image, outputting the image decrypted using the public key. According to this configuration, the video stored in the storage means is stored with a digital signature using a private key, so the authenticity of the camera that sent the video can be ensured. And, the digital signature of the video output from the storage means is verified using a public key, so the authenticity of the video can be ensured, that it has not been tampered with. It should be noted that the captured video includes captured images that are still images.

[0007] Another aspect of the present invention is characterized in that, in the above configuration, the storage means communicates with the child unit or the parent unit via a general-purpose network, and the image output from the child unit is transmitted to the storage means via the general-purpose network. According to this configuration, the video captured by the camera can be stored in a cloud server, for example, and the authenticity of the video can be easily verified from outside via a general-purpose network.

[0008] Another aspect of the present invention is characterized in that in the above configuration, the slave unit embeds time information obtained from the NTP server by a time synchronization protocol in the video and outputs the video. According to this configuration, the exact time is embedded in the digitally signed video, so it can be proven that the time of shooting has not been tampered with, and this can be used to check the video when an incident occurs.

[0009] Another aspect of the present invention is characterized in that, in the above configuration, the sub-unit is a collective entrance unit installed at the entrance of the apartment building, and an ID authentication device is installed near the sub-unit for unlocking the entrance door installed at the entrance to allow a person to enter the apartment building, and the camera begins capturing images when the ID authentication device receives ID information as input, and the sub-unit signs the image captured by the camera and the ID information input to the ID authentication device with a private key and transmits them to a storage means. According to this configuration, the authenticity of the ID can be confirmed in addition to the authenticity of the video, which can prevent impersonation and can be used for reviewing video when an incident occurs.

[0010] Another aspect of the present invention is characterized in that, in the above configuration, the sub-unit is a collective entrance unit installed at the entrance of the apartment building, and a facial recognition device is installed near the sub-unit for unlocking the entrance door installed at the entrance to allow a person to enter the apartment building, the camera begins capturing images in conjunction with the facial recognition operation of the facial recognition device, and the sub-unit signs the video captured by the camera and the facial image inputted into the facial recognition device with a private key and transmits them to a storage means. According to this configuration, in addition to verifying the authenticity of the video, the authenticity of the facial image captured by the facial recognition device can also be verified, which prevents tampering with the facial image and can be used to verify video when an incident occurs. Effect of the Invention

[0011] According to the present invention, the video output from the slave unit to the storage means is digitally signed with a private key, so that tampering can be prevented. And, the digital signature of the video output from the storage means is verified with a public key, so that it can be verified that the video has not been tampered with. Therefore, it is possible to ensure the authenticity that the video is sent from the slave unit, and it is also possible to ensure the authenticity that the video stored in the storage means has not been tampered with. [Brief description of the drawings]

[0012] [Figure 1] 1 is a functional block diagram showing an example of an intercom system according to the present invention; [Diagram 2] FIG. 1 shows an intercom system applied to an apartment building intercom system, and is a system configuration diagram equipped with an ID authentication device. [Diagram 3] FIG. 3 is a functional block diagram of the collective entrance device of FIG. 2. [Figure 4] FIG. 3 is a functional block diagram of the dwelling unit master unit of FIG. 2. [Diagram 5] FIG. 13 is a system configuration diagram showing another example of an intercom system applied to an apartment building intercom system, the system configuration diagram being equipped with a face recognition device. [Figure 6] FIG. 2 is a functional block diagram of the face recognition device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a functional block diagram showing an example of an intercom system according to the present invention, and shows an intercom system used in a detached house. This intercom system 10 is composed of a front door slave unit 1 as a slave unit, a room master unit 2 as a master unit, and a management server 3 as a storage means for storing images. The management server 3 is placed on a general-purpose network N, and the front door slave unit 1 and the room master unit are connected by a transmission line L1.

[0014] The entrance sub-unit 1 is equipped with a call button 11 for calling a resident, a microphone 12a and speaker 12b for making a call, a camera 13 for capturing images of visitors, a private key storage unit 14 for storing a private key for digitally signing and encrypting the data to be output, a timer unit 15 for counting the duration of video transmission, a sub-unit CPU 16 for controlling the entrance sub-unit 1, and a sub-unit transmission unit 17 for communicating with the room main unit 2.

[0015] The room master unit 2 is equipped with a call button 21 for answering calls, a microphone 22a and speaker 22b for making calls, a monitor 23 for displaying images captured by the camera 13, an operation unit 24 for performing operations such as displaying stored images, a public key storage unit 25 for storing a public key for decrypting data that has been digitally signed and encrypted with a private key, a master unit transmission unit 26 for communicating with the front door sub-unit 1, a master unit CPU 27 for controlling the room master unit 2, and an external communication unit 28 for communicating with the management server 3 via the general-purpose network N.

[0016] Management server 3 is a storage means for saving images, and includes a memory unit 31 for storing images, and a public key storage unit 32 for storing a public key. The public key forms a pair with the private key stored in front door subunit 1, and data digitally signed with the private key is verified with the public key. In other words, the digital signature made with the private key can be verified by decrypting and reading data encrypted with the private key using the public key. As a result, it is proven that the source of the data (here, images) is front door subunit 1.

[0017] The operation of the intercom system 10 configured as described above is as follows. However, the basic operation of the intercom, that is, the call / response operation, is the same as in the conventional intercom, so a description thereof will be omitted. Here, the transmission of the image captured by the camera 13 will be mainly described. When the call button 11 of the entrance slave unit 1 is operated to make a call, the camera 13 starts capturing images under the control of the slave unit CPU 16, and the captured image is transmitted together with a call signal to the room master unit 2. At that time, the image is digitally signed with a private key and transmitted. In the room master unit 2 to which the video signal is transmitted, the signature is verified using the public key under the control of the master unit CPU 27, and the video signal is displayed on the monitor 23.

[0018] Moreover, the video transmitted to the parent device 2 is transmitted in an encrypted state to the management server 3 from the external communication unit 28 via the general-purpose network N under the control of the parent device CPU 27. In the management server 3, the encrypted video is stored in the storage unit 31.

[0019] The video stored in the management server 3 in this way can be retrieved and displayed on the monitor 23 by a specified viewing operation of the room master unit 2. In addition, the video can be accessed from a specific mobile phone (not shown) of a resident or the like associated with the source entrance slave unit 1, for example, and the video decrypted by the public key in the management server 3 can be obtained and viewed. On the other hand, camera 13 can be started by operating room master unit 2 without waiting for operation of entrance slave unit 1. The image captured by activated camera 13 is encrypted with a private key and transmitted to room master unit 2 and displayed on monitor 23. At the same time, it is transmitted to management server 3 and stored.

[0020] However, the timer unit 15 counts the transmission time of the captured image from the camera 13 (the recording time for the management server 3 to save the image), and when the image capture by the camera 13 has continued for a predetermined time, such as 60 minutes, it automatically ends and recording is temporarily terminated. After that, the timer unit 15 is reset and recording is resumed. Note that this temporary termination of recording is an operation to prevent synonyms when saving the encrypted image.

[0021] In this way, the video stored in the management server 3 is digitally signed with a private key, ensuring the authenticity of the camera 5 that sent the video. And, the digital signature of the video output from the management server 3 is verified with a public key, ensuring the authenticity of the video that has not been tampered with. Furthermore, since the images captured by the camera 13 are stored in the management server 3 on the general-purpose network N, the authenticity of the images can be easily verified by accessing them from outside.

[0022] Incidentally, the storage destination of the video captured by the camera 13 is the management server 3 on the general-purpose network N, but it may be stored in the room master unit 2 or the entrance slave unit 1. Also, the video captured by the camera 13 is transmitted to the management server 3 via the room master unit 2, but it may be transmitted directly to the management server 3 by providing a communication unit in the entrance slave unit 1 that connects to the general-purpose network N.

[0023] FIG. 2 shows another example of the intercom system of the present invention, and shows a configuration in which the intercom system is applied to an apartment house intercom system installed in an apartment house. An intercom system 40 applied to an apartment building includes an apartment entrance unit 5 as a slave unit and an entrance slave unit 1a installed at the entrance of each dwelling unit, a dwelling unit master unit 6 installed in the rooms of each dwelling unit as a master unit, a management server 3 for storing images, a management room master unit 7, a controller 8 for controlling communication between devices, and a card reader 9a as an ID authentication device for unlocking an entrance door D for returnees or specific contractors without calling the resident. The entrance door D is the door through which one passes when proceeding from the entrance of the apartment building to the living area.

[0024] In addition, the control unit 8 has an external communication unit 81 connected to a general-purpose network N, and is configured to communicate with the management server 3 via the general-purpose network N, as well as to obtain time information from an NTP server 50 that provides time information and notify the collective entrance unit 5.

[0025] The collective entrance unit 5 is installed at the entrance and connected to the control unit 8 via transmission line L2. The management room master unit 7 is installed in the management room and connected to the control unit 8 via transmission line L3. The control unit 8 and each dwelling unit master unit 6 are connected via a master unit trunk line L4. The entrance door D has an electric lock (not shown), which is connected to the control unit 8 via transmission line L5. The card reader 9a is installed near the collective entrance unit 5 and connected to it via transmission line L6.

[0026] Fig. 3 shows a functional block diagram of the collective entrance device 5. As shown in Fig. 3, the collective entrance device 5 includes an operation unit 11a for selecting a destination residence and performing a calling operation, a microphone 12a and a speaker 12b for making a call, a camera 13, a private key storage unit 14, a timer unit 15, a collective entrance device CPU 16a, a collective entrance device transmission unit 17a, and an authentication device connection interface (IF) unit 18 for communicating with the card reader 9a. The same components as those in the front door slave unit 1 in Fig. 1 are given the same reference numerals. The front door slave unit 1a installed at the entrance of each dwelling unit is similar to the front door slave unit 1 in Fig. 1, and in addition to the calling / talking function, it is equipped with a camera 13, a private key storage unit 14, etc.

[0027] Fig. 4 shows a functional block diagram of the dwelling master unit 6. As shown in Fig. 4, the dwelling master unit 6 is equipped with a call button 21 for responding to a call, a microphone 22a and a speaker 22b for making a call, a monitor 23 for displaying the image captured by the camera 13, an operation unit 24a for performing predetermined operations such as displaying the images stored in the management server 3, a public key storage unit 25 for storing a public key for decrypting encrypted data, a dwelling master unit transmission unit 26a for communicating with the control unit 8 and the entrance slave unit 1a, a dwelling master unit CPU 27a for controlling the dwelling master unit 6, and the like. The same reference numerals are used to designate the same components as those in the room master unit 2 in Fig. 1. The control room master unit 7 also has a function of selecting the dwelling unit master unit 6 and making a call / talk to it.

[0028] The card reader 9a has a reading section that reads the ID from the ID card (not shown) carried by a person returning home, etc., when the ID card is held up, and an ID storage section (neither shown) that stores the registered ID. If the read or input ID information is an ID that has been registered and stored in the ID storage section, a permission signal is output to the collective entrance device 5.

[0029] The operation of the intercom system 40 configured as above is as follows, but the following description will focus on the transmission and storage of the image captured by the camera 13. First, a case will be described in which the collective entrance unit 5 is operated to transmit the captured image from the camera 13. When a visitor or the like operates the collective entrance unit 5 to select the residence to be visited and make a call, a call signal is output to the selected residence master unit 6. At the same time, the camera 13 is started up and the captured image is output.

[0030] The video output at this time is digitally signed with a private key, as in the intercom system 10, and is then sent together with the call signal to the called dwelling unit master unit 6 via the control unit 8. At the same time, the video output from the collective entrance unit 5 is also sent from the control unit 8 via the general-purpose network N to the management server 3 and stored there. However, the collective entrance device 5 obtains time information from the NTP server 50 via the control device 8, and the video in which the shooting time is embedded is digitally signed and output according to the time synchronization protocol.

[0031] The image transmitted to the dwelling unit master unit 6 is decrypted using the public key held by the dwelling unit master unit 6, the signature is verified, and the image is displayed on the monitor 23. The image displayed at this time is accompanied by time information embedded in the image by the time synchronization protocol.

[0032] The video stored in the management server 3 can be viewed by performing a specific operation on the dwelling unit master unit 6. It can also be viewed by accessing it from a registered mobile phone or the like. When the stored video is viewed from a registered mobile phone, the video is decrypted using a public key held by the management server 3 and transmitted. The embedded time information is also displayed along with the video. If the public key is also registered in the mobile phone, it is possible to obtain the encrypted image from the management server 3, decrypt it, and display it.

[0033] Next, the transmission of the image captured by camera 13 in the case where collective entrance device 5 is not operated and a person returning home enters ID information into card reader 9a and proceeds to the residential area will be described. Returning residents can use the ID card they carry to unlock the entrance door D and proceed through the entrance to the residential area without having to call the residents from the collective entrance device 5. At this time, the image captured by the camera 13 is transmitted as follows. However, the card reader 9a is installed so that the person who enters the ID information into the card reader 9a is within the field of view of the camera 13.

[0034] When an ID card is held up to the card reader 9a, the card reader 9a reads the ID information and determines whether it is an authorized ID. If it is an authorized ID, a permission signal is output to the collective entrance machine 5. If it cannot be read or the ID is not authorized, a disapproval signal is sent. Upon receiving this permission / disapproval signal, the collective entrance machine 5 starts up the camera 13 to start recording and transmits the captured image to the management server 3. Upon receiving the permission signal, the common entrance device 5 outputs an unlock signal to the control device 8, and the control device 8 unlocks the entrance door D.

[0035] At this time, the image output from the collective entrance device 5 is transmitted with time information embedded therein, in the same manner as when the collective entrance device 5 is operated, and the image is transmitted with a digital signature using a private key. Furthermore, if the ID read by the card reader 9a is an authorized ID, the ID information is also encrypted together with the image and transmitted to the management server 3 for storage. Even if the ID authentication device is not the card reader 9a but is configured to input the ID directly, the same operation can be performed by inputting an ID number or the like.

[0036] In this way, by digitally signing the ID information with a private key along with the video, the authenticity of the ID can be confirmed along with the authenticity of the video of the person whose ID has been authenticated. As a result, it is possible to prevent impersonation and to use it for reviewing video when an incident occurs. Furthermore, because the exact time is embedded in the digitally signed video, it can be proven that the time of capture has not been tampered with, making it useful for reviewing video footage when an incident occurs.

[0037] Incidentally, although the management server 3 stores the video, the video may be stored in the control unit 8. Also, the operation of the front door slave unit 1a is similar to the embodiment shown in Fig. 1, but the video captured by the camera 13 of the front door slave unit 1a is transmitted to and stored in the management server 3 via the dwelling unit master unit 6 and the control unit 8. In this case as well, the video digitally signed with a private key is stored.

[0038] Fig. 5 shows another form of intercom system applied to an apartment block intercom system. Intercom system 40a described here is different from intercom system 40 of Fig. 2 in the form of person authentication for unlocking entrance door D. This intercom system 40a is equipped with a face authentication device 9b, and is configured to unlock the electric lock of entrance door D by face authentication rather than ID authentication.

[0039] The configurations of the collective entrance machine 5, dwelling unit main machine 6, control machine 8, etc. are the same as those in Fig. 2, and the face authentication device 9b is connected to the authentication machine connection IF unit 18 of the collective entrance machine 5 shown in Fig. 3. The face authentication device 9b is installed so that the person to be face-authenticated is within the angle of view of the camera 13 of the collective entrance machine 5.

[0040] Fig. 6 shows a block diagram of the face authentication device 9b. As shown in Fig. 6, the face authentication device 9b includes a camera 91 that captures an image of the face of the person to be authenticated, a monitor 92 that displays the captured image of the face, a human presence sensor 93, a memory unit 94 that stores the face image of the person to be authenticated in association with the dwelling number, a face authentication device CPU 95 that controls authentication, a communication unit 96 that communicates with the collective entrance device 5, and the like.

[0041] The operation of the intercom system 40a configured as described above is as follows. However, since the transmission of the image captured by the camera 13 by operating the collective entrance device 5 is the same as the above embodiment, the description will be omitted here, and the transmission and storage of the image captured by the camera 13 when the face recognition operation is performed will be mainly described. When a person returning home or the like approaches the face recognition device 9b, the human presence sensor 93 detects this and starts recognition control, and the face recognition device CPU 95 starts comparing the face image captured by the camera 91 with the face image stored in the memory unit 94. Meanwhile, the collective entrance device 5 receives a control start signal from the face authentication device 9b that has started authentication control, and the camera 13 of the collective entrance device 5 starts capturing images.

[0042] When the face authentication device 9b determines that the face image captured by the camera 91 is one of the registered persons, it reads the apartment number linked to the face image that it has determined to be the same from the memory unit 94 along with a permission signal, and outputs this together with the face image captured by the camera 91 to the collective entrance device 5. Upon receiving the permission signal, the common entrance device 5 outputs an unlock signal to the control device 8 to unlock the entrance door D. At the same time, the image captured by the camera 13 of the common entrance device 5 and the facial image received from the facial recognition device 9b are combined, digitally signed with a private key, and output together with the dwelling unit number.

[0043] The control unit 8 that receives this video or other signal reads the dwelling unit number information received along with the video signal, and transmits the received video to the dwelling unit master unit 6 for that dwelling unit number. It also transmits the video captured by the camera 13 of the collective entrance unit 5 and the facial image transmitted from the facial recognition device 9b to the management server 3. In this way, the video or other data is stored in the management server 3 with a digital signature attached.

[0044] According to this configuration, in addition to the video captured by camera 13, the authenticated facial image is also digitally signed with a private key and stored. Therefore, in addition to verifying the authenticity of the video captured by camera 13 of the person whose face has been authenticated, the authenticity of the facial image captured by facial authentication device 9b can also be verified. This makes it possible to prevent tampering with the facial image and can be used for video verification when an incident occurs.

[0045] In addition, while the above embodiment is configured to store video output from a sub-unit such as the front door sub-unit 1, what is output may also be an image, which can be digitally signed with a private key in the same way as video, and the signature can be authenticated with a public key. [Explanation of symbols]

[0046] 1, 1a·· Entrance handset (handset), 2·· Residential parent unit (parent unit), 3·· Management server (storage means), 5·· Collective entrance unit (handset), 6·· Residential parent unit (parent unit), 8·· Control unit, 9a·· Card reader (ID authentication device), 9b·· Face authentication device, 10·· Intercom system, 13·· Camera, 14·· Private key storage unit, 25·· Public key storage unit, 40, 40a·· Collective housing intercom system, 50·· NTP server, D·· Entrance door, N·· General-purpose network.

Claims

1. An intercom system having a handset with a calling function and a conversation function, and a base unit with a function for answering calls from the handset, the handset having a camera for capturing an image of a person operating the handset, and the base unit having a monitor for displaying an image captured by the camera, The slave unit has a private key for digitally signing and outputting the image, and encrypts the image captured by the camera with the private key and outputs the image to the storage means. A storage means for storing the captured image of the camera is provided, The storage means stores the received video in an encrypted state and is equipped with a public key for verifying the digital signature created by the private key, and when outputting the stored video, the video is decrypted using the public key.

2. The storage means communicates with the child device or the parent device via a general-purpose network; 2. The intercom system according to claim 1, wherein the video output from said slave unit is transmitted to said storage means via said general-purpose network.

3. 2. The intercom system according to claim 1, wherein said slave unit embeds time information obtained from an NTP server by a time synchronization protocol into the video and outputs the video.

4. The slave unit is a collective entrance unit installed at an entrance of the collective housing complex, and an ID authentication device is installed near the slave unit to unlock an entrance door installed at the entrance to allow a person to enter the collective housing complex, The camera starts capturing an image when the ID authentication device receives the input of ID information, An intercom system as described in any one of claims 1 to 3, characterized in that the handset digitally signs the image captured by the camera and the ID information input to the ID authentication device with the private key and transmits them to the storage means.

5. The slave unit is a collective entrance unit installed at an entrance of the collective housing complex, and a face authentication device is installed near the slave unit to unlock an entrance door installed at the entrance to allow a person to enter the collective housing complex, The camera starts capturing an image in conjunction with a face authentication operation of the face authentication device, The intercom system according to any one of claims 1 to 3, characterized in that the handset digitally signs the video captured by the camera and the facial image input to the facial recognition device with the private key and transmits them to the storage means.

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