JP2006101398A - Monitor system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain improvement in the reliability for monitoring operation by keeping the confidentiality of monitoring data high at all the times by holding a common key to be in a state of less likely to leake and preventing the confidentiality of the common key from lowering, even if the common key is leaked. <P>SOLUTION: Each of Web camera apparatuses CM1-CM5 newly comprises a common key table 25a, a program for detecting changes in the monitoring operation, and a common key generating program 26b. A common key, generated by each of the Web camera apparatuses CM1-CM5 itself, is stored to the common key table 25a; and if a change in the monitoring operation is detected in a state by the program 26a for detecting the change in the monitoring operation, a new common key is generated by the common key generating program 26b. The common key stored in the common key table 25a is then updated to the new common key. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a monitoring system that transmits image data captured by a monitoring camera to a communication device such as a server device or a browsing terminal via a communication network.

  In recent years, for example, a surveillance camera is installed in a home, office, or outdoors, and image data of the surveillance camera is transmitted to a storage / delivery server or a terminal device of a viewer via various communication networks such as the Internet or a LAN (Local Area Network). Attention has been focused on transmission monitoring systems. By using this type of system, a viewer can use a personal computer or mobile phone equipped with browser software to view the state of his / her home, office or outdoors, regardless of location or time. You can browse the device.

  However, in general, this type of system uses a network that can be accessed by an unspecified number of people, such as the Internet, as a communication network. Therefore, in the monitoring system, it is considered to use encryption in order to increase the confidentiality of the image data on the communication network. As an encryption processing apparatus that can be used for communication, for example, an encryption apparatus that generates confidential information such as a secret key in a semiconductor integrated circuit and performs encryption processing in the same semiconductor integrated circuit has been proposed ( For example, see Patent Document 1.)

JP 2000-083019 A

  However, when the conventional cryptographic processing apparatus is used in a monitoring system, once the secret key is generated, it is kept in the semiconductor integrated circuit. For this reason, if the common key is leaked on the communication network or on the monitoring data viewing side, the secret key cannot be changed, and the confidentiality of the image data may not be maintained.

  The present invention has been made paying attention to the above circumstances, and the purpose thereof is to keep the common key in a state in which it is difficult to leak, and to prevent the confidentiality of the common key from being lowered even if it is leaked. Accordingly, it is an object of the present invention to provide a monitoring system in which the confidentiality of the monitoring data is always kept high and the reliability of the monitoring operation is improved.

  In order to achieve the above object, a monitoring system according to the present invention comprises means for generating and storing a common key necessary for encrypting image data in the monitoring camera, and monitoring the stored common key in the monitoring system. Means for updating in response to a change in operation, and encrypts the imaged data with the stored common key and encrypts the stored common key with a public key, and encrypts the imaged data The common key is transmitted to the communication device via the communication network. On the other hand, the communication device receives the encrypted imaging data and the common key transmitted from the monitoring camera, and decrypts the received encrypted common key with a secret key paired with the public key. The received encrypted imaging data is decrypted with the decrypted common key.

  Therefore, according to the present invention, the common key used for encrypting the imaging data is generated in the surveillance camera that cannot be easily touched by a third party, and the generated common key is changed according to a change in the monitoring operation. Updated automatically. For this reason, the common key is kept in a state where it is difficult to leak, and even if the common key leaks on the communication network or on the browsing device side, it is updated each time the monitoring operation changes, so the secret of the common key is high. Retained. As a result, it is possible to keep the confidentiality of the monitoring data, and thus the reliability of the system high.

  Changes in the monitoring operation that triggers the update of the common key include when a monitoring area abnormality is detected from the detection output of the sensor provided in the monitoring camera and the analysis result of the imaging data, When a tilt / zoom operation is performed, when a specific monitoring target area is imaged by the monitoring camera, when a monitoring data browsing request is sent to the monitoring camera or a storage browsing server that stores and distributes the monitoring data, It is conceivable that the authenticity of the user cannot be confirmed by the authentication, or the unauthorized use of the monitoring system is detected.

  Furthermore, it is better not only to update the stored common key in response to the change in the monitoring operation, but also to update it every time a predetermined time elapses. In this way, even when the monitoring operation does not change over a long period of time, the common key can be automatically updated at regular intervals, thereby further improving the confidentiality of the common key.

  Therefore, according to the present invention, the monitoring camera generates and stores the common key necessary for encrypting the imaging data, and updates the stored common key according to the change in the monitoring operation in the monitoring system. As a result, the common key is kept in a state where it is difficult to leak, and even if it is leaked, the confidentiality of the common key is not lowered. It is possible to provide a monitoring system with improved performance.

FIG. 1 is a schematic configuration diagram of a monitoring system using a web (Web) camera device according to an embodiment of the present invention.
In this monitoring system, for example, a monitoring unit provided in a monitoring target facility such as a building or a condominium is connected to a data center via a communication network NW, and the mobile terminals MT1 to MT4 used by a monitor or a viewer are communicated with each other. It is possible to connect to the data center or the Web camera devices CM1 to CM5 via the network NW. The communication network NW is configured by, for example, a WAN (Wide Area Network) including the Internet. The mobile terminals MT1 to MT4 are configured by mobile phones, PDAs (Personal Digital Assistants) or mobile personal computers.

  The monitoring unit provided in the monitoring target facility includes a plurality of Web cameras CM1 to CM5 and monitoring terminals PC3 to PC5, and these Web cameras CM1 to CM5 and monitoring terminals PC3 to PC5 are connected to a LAN (Local Area Network). ) Connected via MNW. The plurality of Web cameras CM1 to CM5 are used for indoor or outdoor monitoring of an apartment, and are installed in, for example, an elevator hall, a passage, and a residential house. The monitoring terminals PC3 to PC5 are installed in a condominium management room and a resident's house, respectively, and are used to view the monitoring video. Further, the LAN MNW is connected to the communication network NW, and the Web cameras CM1 to CM5 and the monitoring terminals PC3 to PC5 are connected to the data center via the communication network NW.

  The data center includes a video storage / delivery device SV1, an authentication server device SV2, a video data conversion device SV3, and monitoring terminals PC1 to PC5 used by a supervisor, and these are laid out in the data center. Are connected to each other.

  The video storage / delivery device SV1 is configured by a workstation including a storage device. Then, the encrypted monitoring data and the encrypted common key transmitted from the Web camera devices CM1 to CM5 are stored in association with each other, and the distribution request transmitted from the monitoring terminals PC1 to PC5 and the portable terminals MT1 to MT4 is added. In response, the stored encrypted monitoring data and encrypted common key are distributed to the requesting monitoring terminals PC1 to PC5 and the browsing portable terminals MT1 to MT4. The common key management table 4 is stored in the storage unit of the video storage / delivery device SV1. The common key management table 4 stores a common key encrypted with a public key and an update time in association with each user ID. An example is shown in FIG.

The authentication server device SV2 includes a personal computer or a workstation, and has a function of performing user authentication in response to a distribution request transmitted from the monitoring terminals PC1 to PC5 and the mobile terminals MT1 to MT4. A user management table 3 is provided in the storage unit of the authentication server device SV2, and is configured to store a user name and a password in association with the user ID. An example is shown in FIG.
When the video data conversion device SV3 distributes the monitoring data from the video storage / delivery device SV1 to the mobile terminals MT1 to MT4, the video data conversion device SV3 converts the video data included in the monitoring data into a format corresponding to the display function of the mobile terminals MT1 to MT4. Convert.

  Incidentally, the Web camera devices CM1 to CM5 are configured as follows. FIG. 2 is a block diagram illustrating a functional configuration of the Web camera device CM1. The Web camera devices CM2 to CM5 have the same configuration as the Web camera device CM1, and thus the description thereof is omitted here.

  The Web camera device CM1 includes a central processing unit CPU (Central Processing Unit) such as a microprocessor, and the CPU 11 via the bus 12 has an imaging unit, an audio input unit, an audio output unit, and an encryption / decryption unit. Each processing unit is connected.

  The imaging unit includes a CCD (Charge Coupled Devices) 13 as an imaging device and an image encoder 14. The image encoder 14 compresses and encodes the video signal output from the CCD 13. As an image compression method, for example, JPEG (Joint Photographic Experts Group), M-JPEG (Motion-JPEG), MPEG (Motion Picture Experts Group), or the like can be used.

  The voice input unit includes a microphone 15, an A / D converter 16, and a voice encoder 17. The microphone 15 is constituted by, for example, an internal microphone or an external microphone. The audio signal collected by the microphone 15 is digitally converted by the A / D converter 16 and further compressed and encoded by the audio encoder 17.

  The audio output unit includes a speaker 18, a D / A converter 19, and an audio decoder 20. The audio decoder 20 decodes the compression-encoded audio data and outputs a digital audio signal. The D / A converter 19 D / A converts the digital audio signal to convert it to an analog audio signal, and outputs the sound from the speaker 18.

  The encryption / decryption processing unit includes an encryption processing unit 21 using a common key, a decryption processing unit 22 using a common key, and an encryption processing unit 23 using a public key. These are realized by, for example, a DSP (Digital Signal Processor). The encryption processing unit 21 using the common key encrypts the compressed and encoded video / audio data using the common key. The common key is generated corresponding to the monitoring terminals PC1 to PC5 and the browsing portable terminals MT1 to MT4, and is stored in the common key table 25a provided in the data memory 25. The common key decryption processing unit 22 decrypts the encrypted audio data with the common key stored in the common key table 25a and reproduces the audio data before encryption.

  The public key encryption processing unit 23 encrypts the common key used for encrypting the video / audio data with the public key. The public key is set for each of the monitoring terminals PC1 to PC5 and the browsing portable terminals MT1 to MT4, and stored in the public key table 25b provided in the data memory 25 in association with the user ID. Note that the public key infrastructure (PKI) technology guaranteed by a trusted third party (TTP) is applied to the public key. The owner of the public key and the private key is linked by a public key certificate issued from a certification authority (CA).

A data memory 25, a program memory 26, and a communication I / F 27 are connected to the CPU 11 via the bus 12.
The data memory 25 uses, for example, a RAM or a hard disk as a storage medium. The data memory 25 stores the common key table 25a and the public key table 25b. As described above, the common key table 25a stores common keys used for communication between the monitoring terminals PC1 to PC5 and the browsing portable terminals MT1 to MT4. This common key is generated by a common key generation program 26b described later. As described above, the public key table 25b stores public keys used for communication between the monitoring terminals PC1 to PC5 and the browsing portable terminals MT1 to MT4. This public key is distributed from the certificate authority as described above.

The program memory 26 stores a monitoring operation detection program 26a and a common key generation program 26b as control programs according to the present invention.
The monitoring operation detection program 26a detects a change in monitoring operation by the monitoring system. Here, as the monitoring operation of the detection target, the pan / tilt / zoom operation of the Web camera device, the change of the image detected by image recognition processing of the monitoring image data, a sensor connected to the camera ( An abnormality in a monitoring target area detected by a monitoring camera (not shown), an imaging operation for a specific monitoring target area by a monitoring camera, and a browsing request transmitted from the monitoring terminals PC1 to PC5 or the browsing portable terminals MT1 to MT4 are images. For example, when it is received by the storage / delivery device SV1, the authenticity of the monitor or the viewer cannot be confirmed by the authentication of the authentication server device SV2, or the unauthorized use of the monitoring system is detected. Note that the pan / tilt / zoom operation of the Web camera device is performed by a supervisor directly operating a control switch (not shown) provided in the Web camera device, or the monitoring terminals PC1 to PC5 and the mobile terminal device in the data center. It is controlled by a remote control signal sent from MT1 to MT4.

The common key generation program 26b updates each common key stored in the common key table 25b when a change in the monitoring operation is detected by the monitoring operation detection program 26a.
Note that the communication I / F 27 communicates with the communication network NW under the control of the CPU 11.

Next, various transmission operations of monitoring data by the monitoring system configured as described above will be described.
(1) Live video transmission operation in the Web camera device CM1
FIG. 5 is a flowchart showing a live video transmission control procedure and its contents in the Web camera apparatus CM1 shown in FIG. Here, a case where the supervisor views the live video of the Web camera device CM1 will be described as an example.

  First, the supervisor inputs a user authentication request together with the user name and password at the monitoring terminal PC1. Then, the user name and password are transferred from the monitoring terminal PC1 to the authentication server device SV2. The authentication server SV2 accesses the user management table 3 provided in the storage unit, and collates the received user name and password. As a result of this collation, when the legitimacy of the supervisor is confirmed, the corresponding user ID is returned from the authentication server device SV2 to the monitoring terminal PC1 as the request source. When the user ID is returned, the monitoring terminal PC1 transmits the user ID and the live video distribution request to the Web camera device CM1.

  When the Web camera device CM1 receives the live video distribution request, first, in step S5a, the video data picked up by the CCD 13 is compressed and encoded by the image encoder 14, and then taken into the temporary data memory. Next, in step S5b, the common key table 25a provided in the data memory 25 is accessed, and the common key corresponding to the user ID received together with the live video distribution request is read. Then, the video data temporarily stored in the data memory is encrypted with the read common key. Next, in step S5c, the public key table 25b is accessed based on the received user ID, and the public key corresponding to the user ID is read out. Then, the common key used for the encryption processing of the video data is encrypted with the read public key. Finally, in step S5d, the encrypted common key and the user ID are superimposed on the encrypted video data and transmitted to the distribution request source monitoring terminal PC1.

  Here, since the common key is updated every time a constant time interval and a monitoring operation are changed by a common key update process described later, the common key may be updated during transmission of the encrypted video data. Therefore, each time the common key is updated, the updated new common key is re-encrypted with the public key, and this encrypted common key is superimposed on the encrypted video data together with information indicating the update timing and the user ID. To do.

  The following method is used as a method for superimposing the encrypted common key on the encrypted video data. For example, in the MPEG-4 or JPEG data format, a user area capable of storing metadata is prepared in addition to the video signal area, and the encrypted common key is stored in this user area. In the case of the JPEG method, an encryption common key is superimposed for each frame of video data. Further, when broadcasting video data to a plurality of observers or viewers, it is necessary to superimpose a plurality of common keys corresponding to the plurality of observers or viewers on the video data. May not be able to store all encrypted common keys in the user area. In this case, an additional information area is newly defined in the data format, and the encrypted common key is stored in this additional information area. In this case, an identifier may be added before and after the additional information area in order to distinguish the additional information area from the video signal area.

(2) Live video reception display operation in the monitoring terminal PC1
FIG. 6 is a flowchart showing the procedure and contents of video browsing control in the monitoring terminal PC1. After transmitting the distribution request described above, the monitoring terminal PC1 receives the encrypted video data and the encrypted common key transmitted from the Web camera device CM1 in step S6a. In step S6b, the received encrypted common key is decrypted with a secret key paired with the public key used by the Web camera device CM1. Next, in step S6c, the encrypted video data is decrypted using the decrypted common key. Then, after the decoded video data is restored to the original image data by the decompression decoding process, it is displayed on the display unit in step S6d.

(3) Common key update operation in the Web camera device CM1
FIG. 7 is a flowchart showing a common key update control procedure and its contents in the Web camera device CM1. The CPU 11 of the Web camera device CM1 executes the monitoring operation detection program 26a as a resident program, and determines whether there is a change in the monitoring operation in step S7a. Here, the change in the monitoring operation refers to the pan / tilt / zoom operation of the Web camera device as described above, a change of a predetermined amount or more of the image detected by performing image recognition processing on the monitoring image data, Abnormality of the monitoring target area detected by a connected sensor (not shown), imaging operation for a specific monitoring target area by the monitoring camera, transmitted from the monitoring terminals PC1 to PC5 or the browsing portable terminals MT1 to MT4 When the video storage / delivery device SV1 is received, when the authenticity of the monitoring server or the viewer cannot be confirmed by the authentication of the authentication server device SV2, or when the unauthorized use of the monitoring system is detected.

  When the change in the monitoring operation is detected in the determination in step S7a, the CPU 11 of the Web camera device CM1 proceeds to step S7c, where the common key generation program 26b is executed to generate a new common key. Next, the common key stored in the common key table 25a provided in the data memory 25 is updated to the generated common key. At this time, the common key table 25a also stores the update timing of the common key. In step S7d, the public key of the corresponding user is read from the public key table 25b, and the updated common key is encrypted with the read public key. Subsequently, in step S7e, the encrypted common key is transmitted to the video storage / delivery device SV1 together with the update timing information and the corresponding user ID.

  On the other hand, if no change in the monitoring operation is detected in the determination in step S7a, the CPU 11 proceeds to step S7b, where it determines whether or not a certain time has elapsed since the previous update timing of the common key. Then, when the predetermined time has elapsed, the process proceeds to step S7c, and the corresponding common key update process is executed by the processes in steps S7c to S7e described above. If it is determined in step S7b that a predetermined time has not elapsed since the update timing, the process is terminated.

(4) Creation operation of common key management table in video storage / delivery device SV1
Next, the creation operation of the common key management table 4 in the video storage / delivery device SV1 will be described. FIG. 8 is a flowchart showing the processing procedure and the processing contents.
First, in step S8a, the video storage / delivery device SV1 receives the encrypted common key transmitted from the Web camera device CM1 together with the update timing information and the user ID. In step S8b, an update time is detected from the update timing information, and the received encrypted common key and the detected update time are stored in the common key management table 4 in association with the user ID. An example of the common key management table 4 created in this way is shown in FIG.

(5) Browsing operation of stored video by monitoring terminal PC1
FIG. 9 is a flowchart showing the distribution operation of the stored video data in the monitoring terminal PC1 and the stored video distribution device SV1. First, the monitor inputs a user name, a password, and time information desired for browsing (hereinafter referred to as browsing time information) from the keyboard in the monitoring terminal PC1, and performs a browsing request operation for the stored video. Then, in step S9a, the monitoring terminal PC1 sends a stored video distribution request together with the user name, password, and browsing time information to the video storage distribution apparatus SV1. As the user name and password, a user name and password stored in advance in an external removable medium such as an IC card can be used.

  Upon receiving the stored video distribution request in step S9b, the video storage / delivery device SV1 transmits a user authentication request together with the user name and password to the authentication server device SV2 in step S9c. The authentication server device SV2 accesses the user management table 3 to perform user authentication based on the received user name and password, and when the user's validity is confirmed, the corresponding user ID is assigned to the video storage / delivery device SV1. Return to In step S9d, the video storage / delivery device SV1 acquires the encrypted common key corresponding to the time of the distribution request from the common key management table 4 based on the returned user ID and the browsing time information received in step S9a. In step S9e, the video storage / delivery device SV1 transmits the acquired encrypted common key to the distribution request source monitoring terminal PC1 via the LAN DNW.

  On the other hand, the monitoring terminal PC1 receives the encrypted common key transmitted from the video storage / delivery device SV1 in step S9f. In step S9g, the received encrypted common key is decrypted with the secret key held by the monitoring terminal PC1 itself. Then, the decrypted common key is held.

  Next, in step S9k, the monitoring terminal PC1 transmits a stored video distribution request to the video storage / distribution apparatus SV1 via the LAN DNW. The video storage / delivery device SV1 receives the stored video distribution request transmitted from the monitoring terminal PC1 in step S9i, reads the corresponding encrypted video data from the storage device in step S9j, and reads the read encrypted video. Data is transmitted to the requesting monitoring terminal PC1.

  In step S91, the monitoring terminal PC1 receives the transmitted encrypted video data. In step S9m, the received encrypted video data is decrypted with the common key decrypted in step S9g. In step S9n, the decoded stored video data is displayed on the display unit. The video storage / delivery device SV1 transmits the encrypted video data after step S9j, and accesses the common key management table 4 to monitor the next update time of the encrypted common key acquired in step S9d. To do. When it is recognized that the next update time is approaching, an encrypted common key corresponding to the next update time is acquired from the common key management table 4. The obtained encrypted common key is transmitted to the monitoring terminal PC1 that is the request source. Thus, the requesting monitoring terminal PC1 automatically receives the encrypted common key corresponding to the browsing time in accordance with the monitoring video being browsed.

  As described above, in this embodiment, the Web camera devices CM1 to CM5 are newly provided with the common key table 25a, the program 26a for detecting a change in the monitoring operation, and the common key generation program 26b. Then, the common key generated by the Web camera devices CM1 to CM5 is stored in the common key table 25a, and when the change of the monitoring operation is detected in this state by the program 26a, the common key is detected. A new common key is generated by the generation program 26b, and the common key stored in the common key table 25a is updated to the new common key.

  Therefore, according to this embodiment, the common key used for encrypting the video data is generated in the Web camera devices CM1 to CM5 that cannot be easily touched by a third party, and the generated common key is monitored. It is automatically updated as the operation changes. For this reason, since the common key is held in a state in which it is difficult to leak, and even if the common key is leaked on the communication network NW or the terminal on the browsing side, it is updated each time the monitoring operation is changed. Is held high. As a result, it is possible to keep the confidentiality of the monitoring data, and thus the reliability of the system high.

In addition, the stored common key is updated not only in accordance with the change in the monitoring operation but also every time a predetermined time elapses from the update time point. In this way, even when the monitoring operation does not change over a long period of time, the common key can be automatically updated at regular intervals, thereby further improving the confidentiality of the common key.
As a specific application, normal elevator halls and passages are monitored by accessing the video storage / delivery device SV1 through the monitoring terminals PC1 and PC2 in the data center (unique centralized storage monitoring). In addition, the security guards browse and monitor the live video with the mobile terminal devices MT1 and MT2 before receiving the report and arriving at the building / apartment (remote monitoring). In addition, by installing in a residential home like the Web camera devices CM4 and CM5, the mobile terminal devices MT3 and MT4 can remotely monitor the intrusion into the residential home when absent (personal home remote monitoring). . It is also possible to view and check the monitoring video stored in the data center from the PCs 4 and 5 installed in the residents' homes after returning home (individual home absence monitoring).

  The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the video accumulation / delivery device SV1, the authentication server device SV2, and the video data conversion device SV3 are described as separate configurations, but these are combined and integrated into one or more server devices. It is also possible to do. With this configuration, the number of server devices can be reduced, and the cost required for the entire system can be reduced.

Further, instead of the public key used for encrypting the common key in the Web camera devices CM1 to CM5, an encryption key arbitrarily generated in the system is used, and the common key is encrypted with this encryption key. May be.
Furthermore, the image captured by the Web camera device may be a still image, a semi-moving image, or a moving image. The information to be transmitted is not limited to image data, but may be so-called multimedia information to which audio data and various control data are added. In addition, the number of Web camera devices CM1 to CM5, the monitoring terminals PC1 to PC5 and the mobile terminal devices MT1 to MT4, the configuration of the common key table 25a and the public key table 25b stored in the data memory 25, items to be stored, and each program The processing procedure and the processing content can be modified in various ways without departing from the gist of the present invention.

  In short, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram of the system which implement | achieves one Embodiment of the monitoring system concerning this invention. The block diagram which shows the function structure of the Web camera apparatus of the system shown in FIG. The figure which shows the structure of the user management table memorize | stored in the authentication server apparatus shown in FIG. The figure which shows the structure of the common key management table memorize | stored in the video | video accumulation | storage delivery apparatus shown in FIG. 3 is a flowchart showing a live video transmission control procedure and contents in the Web camera device CM1 shown in FIG. The flowchart which shows the procedure of the video browsing control in the monitoring terminal shown in FIG. 1, and its content. The flowchart which shows the common key update control procedure and its content in the Web camera apparatus shown in FIG. The flowchart which shows the process sequence of the common key management table preparation operation | movement in the video storage delivery apparatus shown in FIG. 1, and its processing content. The flowchart which shows the delivery operation | movement of the accumulation | storage video data in the monitoring terminal and accumulation | storage video delivery apparatus shown in FIG.

Explanation of symbols

  CM1 to CM5 ... Web camera device, SV1 ... Video storage / delivery device, SV2 ... Authentication server device, SV3 ... Video data conversion device, PC1-PC5 ... Monitoring terminal, MT1-MT4 ... Mobile terminal device, NW ... Communication network, DNW , MNW ... LAN, CA ... certificate authority, 11 ... CPU, 12 ... bus, 13 ... CCD, 14 ... image encoder, 15 ... microphone, 16 ... A / D converter, 17 ... audio encoder, 18 ... speaker, 19 ... D / A converter, 20 ... audio decoder, 21 ... common key encryption processing unit, 22 ... common key decryption processing unit, 23 ... public key encryption processing unit, 25 ... data memory, 25a ... common key table, 25b ... public key table, 26 ... program memory, 26a ... monitoring operation detection program, 26b ... common key generation program, 27 ... communication I / F 3 ... user management table, 4 ... the common key management table.

Claims (1)

A monitoring camera that captures an image of the monitoring target area and a communication device that can be connected to the monitoring camera via a communication network, and the imaging data of the monitoring target area is encrypted and transmitted from the monitoring camera to the communication device. A monitoring system,
The surveillance camera is
Means for generating a common key necessary for the encryption;
Means for storing the generated common key;
Means for updating the stored common key in response to a change in monitoring operation by the monitoring system;
Means for encrypting the imaging data with the stored common key;
Means for encrypting the stored common key with a public key;
Means for transmitting the encrypted imaging data and the encrypted common key to the communication device via the communication network;
The communication device
Means for receiving the encrypted imaging data and the encrypted common key transmitted from the monitoring camera via the communication network;
Means for decrypting the received encrypted common key with a private key paired with the public key;
A monitoring system comprising: means for decrypting the received encrypted imaging data with the decrypted common key.

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