JP2009253305A - Video signature system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video signature system having a signature generating device for generating a signature for a series of videos and a signature verifying device for verifying a signature, capable of verifying the continuity of videos beyond a range of one-time signature generation. <P>SOLUTION: In the signature generating device, an initial hash value calculating means calculates a hash value for each of video data in the plurality of continuous video data obtained by dividing a series of videos, in which the header data are data about tail end video data in a predetermined number of data to which a (a-1)th signature is placed in an a-th signature and the (second to predetermined number)th data are the (predetermined number-1)th continuous data subsequent to the tail end video data. A final hash value acquiring means uses the predetermined number of hash values and a predetermined hash function to acquire one hash value in accordance with predetermined processing procedures, and the signature generating means generates a signature for the one hash value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a video processing system that digitally signs a video (image) taken by an imaging device such as a surveillance camera and transmits and records it via a network, and more particularly to a digital signature for video data divided into a plurality of parts. The present invention relates to a video signature system using technology.

  Conventionally, video surveillance systems have been installed in public facilities such as hotels, buildings, convenience stores, financial institutions, dams and roads for the purpose of crime prevention and accident prevention. In the video surveillance system, the surveillance target is photographed by an imaging device such as a camera, and the photographed video is transmitted to a monitoring center such as a management office or a security room, and the supervisor monitors the video for the purpose and necessity. Depending on the situation, a warning or warning is given, or the video is recorded or saved.

In recent years, in the field of such a video surveillance system, a network-type video surveillance system that digitizes surveillance camera video and transmits and monitors video over an IP network represented by the Internet is becoming widespread. is there.
In the network-type video surveillance system that is currently mainstream, live video is distributed via a network from a video transmission device connected to a surveillance camera to a video reception device. This system is a system suitable for a monitoring form in which a resident supervisor always watches the distributed video (and audio) and responds according to the situation when a problem occurs.

On the other hand, as video monitoring, in addition to the “live type monitoring” which mainly focuses on the live video monitoring as described above, “recording and saving the monitoring video and viewing the recorded video retroactively when a problem occurs” There is also a monitoring form of “record type monitoring”, and there is a customer need for such “record type monitoring” mainly in financial institutions and shops.
In the network-type video monitoring system, it is possible to use a “video storage / delivery server” that can meet the needs of such “recording-type monitoring”.

  In addition, in order to improve the evidence of video, digital signature is applied to video data, and the networked video monitoring system with a signature that enables detection of video data flowing in the network and alteration of recorded video data can be detected. It is spreading.

One configuration example of a video distribution system that can be used as such a signed network type video monitoring system is shown in FIG. 1 referred to in an embodiment described later. Here, for convenience of explanation, FIG. 1 is referred to, but there is no intention to unnecessarily limit the present invention.
In the following, a case where the RSA-PSS method, which is a kind of digital signature technology, is used for signature generation and signature verification will be described as an example.

Here, as a feature of video data in fields such as video surveillance systems, the amount of data is large, and video data may be extracted and stored for the purpose of saving network bandwidth or recording device capacity. For example, the number of processes per unit time is large, such as 30 sheets per second.
On the other hand, for example, it is considered to be able to arbitrarily extract and save a plurality of data and to improve the efficiency by reducing the processing load of generating a signature per video (hereinafter, referred to as “economics”). And referred to as “Technical Example 1”).

In the signature verification in the video surveillance system, there are cases where it is desired to verify not only the video data of the divided single frames but also continuous video data including continuity. For example, it is confirmed that only inconvenient portions of continuous video data have been extracted and edited, or whether any other signed video data has been inserted into the continuous video data and has not been edited. There is a case where it is desired to confirm or confirm whether video data in the middle of a certain continuous video data is replaced with another video data.
Note that even if a signature method that can be arbitrarily extracted from a plurality of data and stored and the processing load for generating a signature per image is suppressed is adopted as in “Technical Example 1” described above. For example, there is a case where it is desired to check a part that has not been extracted, including the continuity of video data.

With reference to FIGS. 7 and 8, a signature generation method in a networked video surveillance system with a signature according to a conventional example will be described.
7 and 8 show an example in which the number n of messages to be processed at the time of one signature generation in the signature generation apparatus 5 is four.
In this example, the video data is divided and processed, for example, for parallel processing of video encoding, and at a later date, only a part of the video (for example, an important part) is left, This is to save the storage capacity.
In this example, it is assumed that the divided video data is one JPEG frame.

FIG. 7 schematically shows an example of a relationship between a series of videos and a signature in the network type video surveillance system with a signature.
For convenience of explanation, in FIG. 7, the same reference numerals are given to the signature generation engine 31 similar to that shown in FIG.
Further, a is an integer of 2 or more.

M1 _{(a-1) to} M4 _(a-1) are divided video data processed at the time of (a-1) signature generation, and M1 _{(a) to} M4 _(a) are , Divided video data to be processed at the time of a-th signature generation.
h _{0,1 (a-1) to} h _{0,4 (a-1)} and h _{0,1 (a) to} h _{0,4 (a)} are respectively represented by M _{1 (a-1) to} M _{4 (} It is a hash value obtained by inputting _a-1) and M1 _{(a) to} M4 _(a) into the hash function h.

h _{1,1 (a-1)} is a hash value obtained by inputting the result of concatenating h _{0,1 (a-1)} and h _{0,2 (a-1)} to the hash function h.
_{Similarly, h 1,2 (a-1) is, h 0,3 (a-1)} and _{h 0,4 (a-1)} hash obtained by inputting the result of concatenating the hash function h to values It is.
H _{1,1 (a)} is a hash value obtained by inputting the result of concatenating h _{0,1 (a)} and h _{0,2 (a)} to the hash function h.
Similarly, h _{1,2 (a)} is a hash value obtained by inputting the result of concatenating h _{0,3 (a)} and h _{0,4 (a)} to the hash function h.

h _{2,1 (a-1)} is a hash value obtained by inputting the result of concatenating h _{1,1 (a-1)} and h _{1,2 (a-1)} to the hash function h.
Further, h _{2,1 (a)} is a hash value obtained by inputting the result of concatenating h _{1,1 (a)} and h _{1,2 (a)} to the hash function h.
The signature generation engine 31 calculates _a signature value σ _(a-1) from h _{2,1 (a-1)} and the secret key, and also calculates _a signature value σ _(a) from h _{2,1 (a)} and the secret key. Is calculated.

The video data M _{1 (a-1) to} M _{4 (a-1)} and M _{1 (a) to} M _{4 (a)} and signature values σ _(a-1) and σ _(a) are obtained from the signature generation device 5. Then, it is delivered to the video receiver 3 via the video storage / delivery server 4 or directly.
These pieces of information are further distributed from the video reception device 3 to the signature verification device 6. In addition, each hash value may be distributed in the same manner as the video data and the signature, if necessary, so that the video data stored arbitrarily extracted can be verified.
The same applies to signature generation after the (a + 1) th time.

FIG. 8 shows a flowchart of an example of processing performed by the signature generation device 5.
For convenience of explanation, in FIG. 8, the same reference numerals are given to the same processes as those shown in FIG. 3 referred to in the embodiment described later, but here the present invention is unnecessarily limited. There is no intention to do.

First, in the initialization process (step S1), necessary memory allocation, variable initialization process, and the like are performed.
Next, in the counter value (i) count-up process (step S2), 1 is added to the variable i.
Next, in the process of receiving and storing the video data (M _i ) in the video buffer (step S3), the video data (M _i ) received from the video transmission device 2 is stored in the video buffer.

The hash value _{h 0, i} calculation processing of the video data _{(M i)} to generate a hash value _{h 0, i} of (step S4), and the video data of the video buffer which stores _{(M i).}
In the process of determining whether i has reached the number of messages to be processed at one signature generation (4 in this example) (step S5), i is 4 which is the number of messages to be processed at one signature generation. Branch depending on whether or not there is. Specifically, if i has not reached 4, the process branches to a counter value (i) count-up process (step S2). If i has reached 4, the counter value (i) is set to 0. The process branches to the process (step S31).

In the process of setting the counter value (i) to 0 (step S31), 0 is stored in the variable i.
Next, in the hash value h _1,1 calculation process of the concatenated value of h _0,1 and h _0,2 (step S7), the concatenation of the hash value h _0,1 and h _0,2 calculated in the process of step S4 is performed. The hash value h _1,1 of the value is calculated.
Next, in the hash value h _1,2 calculation process of the concatenated value of h _0,3 and h _0,4 (step S8), the concatenation of the hash value h _0,3 and h _0,4 calculated in the process of step S4 is performed. The hash value h _1,2 of the value is calculated.
Next, in the hash value h _2,1 calculation process of the concatenated value of h _1,1 and h _1,2 (step S9), the hash values h _1,1 and h _1, calculated in the processes of step S7 and step S8 _. It calculates a hash value _{h 2,1} the _second coupling values.

Next, in the signature (σ) generation process (step S10), the signature (σ) is generated by inputting the h ₂ , ₁ and the secret key calculated in step S9 to the signature engine 31.
Next, in the signature (σ) distribution process (step S11), the signature (σ) is distributed to the video accumulation / delivery server 4 or the like. At this time, in this example, the video is also distributed at the same time. However, as another configuration example, the video storage / delivery server 4 may receive the video directly from the video transmission device 2. Further, the hash value may be distributed simultaneously.

In the video buffer clear process (step S32), the used video buffer is cleared so that it can be reused.
In the video reception end determination process (step S13), the presence / absence of a video to be received is confirmed. If there is a video to be received, the process branches to the counter value (i) count-up process (step S2) and is received. If there is no video to be processed, the process branches to an end process (step S14).
In the end process (step S14), a process necessary to end the process such as releasing the secured memory is performed.

With reference to FIGS. 7 and 9, a signature verification method in a networked video surveillance system with a signature according to a conventional example will be described. The signature verification method of this example corresponds to the signature generation method shown in FIGS.
FIG. 9 shows a flowchart of an example of processing performed by the signature verification apparatus 6.
For convenience of explanation, in FIG. 9, the same reference numerals are given to the same processes as those shown in FIG. 3 and FIG. 4 referred to in the embodiment described later. There is no intention to limit it to unnecessary. For convenience of explanation, in FIG. 9, the same processes as those shown in FIG. 8 are denoted by the same reference numerals.

First, in the initialization process (step S1), necessary memory allocation, variable initialization process, and the like are performed.
Next, in the counter value (i) count-up process (step S2), 1 is added to the variable i.
Next, in the process of reading the video data (M _i ) and storing it in the video buffer (step S 21), the video data (M _i ) is read from the removable medium 21 connected to the signature verification device 6 and stored in the video buffer. .

The hash value _{h 0, i} calculation processing of the video data _{(M i)} to generate a hash value _{h 0, i} of (step S4), and the video data of the video buffer which stores _{(M i).}
In the process of determining whether i has reached the number of messages to be processed at one signature generation (4 in this example) (step S5), i is 4 which is the number of messages to be processed at one signature generation. Branch depending on whether or not there is. Specifically, if i has not reached 4, the process branches to a counter value (i) count-up process (step S2). If i has reached 4, the counter value (i) is set to 0. The process branches to the process (step S31).

In the process of setting the counter value (i) to 0 (step S31), 0 is stored in the variable i.
Next, in the hash value h _1,1 calculation process of the concatenated value of h _0,1 and h _0,2 (step S7), the concatenation of the hash value h _0,1 and h _0,2 calculated in the process of step S4 is performed. The hash value h _1,1 of the value is calculated.
Next, in the hash value h _1,2 calculation process of the concatenated value of h _0,3 and h _0,4 (step S8), the concatenation of the hash value h _0,3 and h _0,4 calculated in the process of step S4 is performed. The hash value h _1,2 of the value is calculated.
Next, in the hash value h _2,1 calculation process of the concatenated value of h _1,1 and h _1,2 (step S9), the hash values h _1,1 and h _1, calculated in the processes of step S7 and step S8 _. It calculates a hash value _{h 2,1} the _second coupling values.

In the signature (σ) reading process (step S22), the signature (σ) is read from the removable medium 21 connected to the signature verification device 6.
Next, in the signature verification processing from the signature (σ) and the hash value h _2,1 (Step S23), the signature (σ), the hash value h _2,1 and the public key are input, and the success or failure of signature verification is returned.
In the video buffer clear process (step S32), the used video buffer is cleared so that it can be reused.

  In the video reading end determination process (step S24), it is determined from the removable media 21 connected to the signature verification device 6 whether there is a video to be read next. If there is a video to be read next, the process branches to a counter value (i) count-up process (step S2). If there is no video to be read next, the process branches to a verification result display process (step S25).

In the verification result display processing (step S25), the success or failure of the signature verification output in the signature verification processing (step S23) is displayed on the video display device 12 of the signature verification device 6.
Specifically, for example, as shown in FIG. 6 referred to in an embodiment described later, a verification result dialog 55 is displayed if the signature verification is successful, and a verification result dialog 56 is displayed if the signature verification is unsuccessful. .
In the end process (step S14), a process necessary to end the process such as releasing the secured memory is performed.

Here, as an example, a procedure for performing signature verification of M _{1 (a-1)} shown in FIG. 3 will be described.
First, the signature verification apparatus 6 inputs M1 _(a-1) itself to the hash function h and calculates _a hash value _{h0,1 (a-1)} . Then, the calculated hash value _{h 0, 1 (a-1)} and _{M 2 (a-1)} hash value _{h 0, 2} calculated from _(a-1) a is input to the hash function h hash values _{h 1 , 1 (a-1)} . Similarly, h _{2,1 (a-1)} is calculated from h _{1,1 (a-1)} and h _{1,2 (a-1)} . When this value and the public key are input to the signature verification engine 31, the signature can be verified. At this time, if M1 _(a-1) is falsified data, signature verification fails.

For example, when the signature verification of M _{1 (a-1)} , M _{2 (a-1)} , M _{3 (a-1)} , and M _{4 (a-1)} succeeds, the video data M _{1 (a-1)} , M2 _(a-1) , M3 _(a-1) , and M4 _(a-1) can be said to be continuous. When the signature verification of M _{1 (a)} , M _{2 (a)} , M _{3 (a)} , and M _{4 (a)} is successful, the video data M _{1 (a)} , M _{2 (a)} , M _{3 ( a)} and M4 _(a) can be said to be continuous. This is because the signature verification fails if the order of the video data is changed, a part of the video data is extracted, or another video is inserted.

However, although M _{4 (a-1)} and M _{1 (a)} are continuous, there is a problem that there is no method for confirming the continuity. For example, M _{1 (a)} , M _{2 (a)} , M _{3 (a)} , M _{4 (a)} are extracted, and even if M _{1 (a + 1)} is next to M _{4 (a-1)} , it is extracted. I didn't understand that.
As described above, the conventional method has a problem that it is not possible to sufficiently confirm the continuity.

  The present invention has been made in view of such conventional circumstances, and an object thereof is to provide a video signature system capable of verifying the continuity of video beyond the scope of one signature generation.

To achieve the above object, the present invention includes a signature generation apparatus that generates a signature for a series of videos, and a signature verification apparatus that performs signature verification using part or all of the series of videos and the signature. The video signature system has the following configuration.
That is, in the signature generation device, the initial hash value calculation means uses (a-1) for the a-th signature (a is an integer of 2 or more) for a plurality of continuous video data obtained by dividing the series of videos. ) Among the predetermined number of data to be signed for the first time, the data related to the predetermined number of video data at the end is set as the first data at the beginning and follows the video data at the end (the predetermined number − 1) Using a predetermined hash function for the predetermined number of pieces of data as the second to predetermined number of pieces of continuous video data, a hash value is calculated. A final hash value acquisition unit acquires one hash value by a predetermined processing procedure using the predetermined number of hash values calculated by the initial hash value calculation unit and a predetermined hash function. The signature generation unit generates a signature for the hash value acquired by the final hash value acquisition unit.
In the signature verification apparatus, the first means having the same function as the initial hash value calculating means performs the same processing as the initial hash value calculating means. A second unit having the same function as the final hash value acquisition unit performs the same process as the final hash value acquisition unit. The signature verification unit performs signature verification using the hash value acquired by the second unit and the signature.

  Therefore, by making the data related to the last video data out of a predetermined number of data to be signed (a-1) times as the first data in the next a-th signature, (a-1) -th time The continuity between a predetermined number of data to be signed and a predetermined number of data to be subjected to the a-th signature can be verified, and video continuity can be verified beyond the scope of one signature generation. it can.

Here, various videos may be used as a series of videos to be signed.
In addition, as a signature verification target, for example, a part of a series of videos may be used, or the whole series of videos may be used.
Various numbers may be used as the number of data (predetermined number) for which one signature is performed.
Various hash functions may be used.
In the process of generating a signature for one hash value, for example, secret key data is used.
In the process of performing signature verification using one hash value and a signature, for example, public key data is used.

The video signature system according to the present invention has the following configuration.
That is, as an example of the configuration, the initial hash value calculation means is a predetermined (a-1) th signature for the a-th signature for a plurality of continuous video data obtained by dividing the series of videos. When the data related to the predetermined number of video data at the end of the number of data is set as the first data at the top, the end video data itself is set as the top data.
As another example of the configuration, the initial hash value calculation means is a predetermined (a-1) th signature for the a-th signature for a plurality of continuous video data obtained by dividing the series of videos. A hash value obtained by inputting the end video data to a predetermined hash function when the data related to the predetermined number of video data at the end of the number of data is the first data at the top Is the head data.

  As described above, according to the video signature system of the present invention, an overlapping portion (identical or related data) is provided in the data to be used in the (a-1) th signature generation and the ath signature generation. Therefore, the continuity of the video can be verified beyond the scope of one signature generation.

Embodiments according to the present invention will be described with reference to the drawings.
FIG. 1 shows a configuration example of a video distribution system that can be used as a signed network type video surveillance system according to an embodiment of the present invention.
The video distribution system of this example includes a video generation device 1, a video transmission device 2, a video reception device 3, a video display device 11, a video storage / delivery server 4, a recording medium 13, a signature generation device 5, and a signature verification. A device (video browsing device) 6 and a video display device 12, a network medium 7, and a removable medium 21 are provided.

  The network medium 7 is composed of, for example, a network cable, a wireless LAN (Local Area Network), a public line, or the like, and has a function of transmitting transmitted data. In this example, the network medium 7 includes network devices such as routers and hubs. The video transmission device 2, the video reception device 3, the video storage / delivery server 4, and the signature generation device 5 are connected to the network medium 7 and can communicate with each other.

The video generation device 1 is a video generation device having an image sensor such as a camera, for example, and has a function of generating light by converting light into electricity.
The video transmission device 2 is, for example, an encoder device that includes an interface for receiving video from the video generation device 1, an image codec, and a network interface, and converts the input video from the video generation device 1 into a form suitable for network transmission. And has a function of transmitting to the network medium 7. For example, if the input video from the video generation device 1 is an analog video, the video transmission device 2 performs digital conversion, and performs compression processing depending on the transmission band of the network medium 7.
Note that the video generation device 1 and the video transmission device 2 may be configured, for example, as a single device.

  The video receiver 3 is, for example, a decoder device with a built-in network interface and image codec, an interface for outputting video to the video display device 11, and an interface to the removable medium 21. The video receiver 3 receives video transmitted through the network medium 7. The video display device 11 has a function of converting to a displayable form and outputting it. For example, when the video display device 11 is a television monitor, the video receiving device 3 performs analog conversion, and when the received video is a compressed video, the video receiving device 3 performs an expansion process using an image codec. To do.

  The video reception device 3 has a function of receiving a video with a signature and storing the received signature and video in the removable medium 21 in a manner that can be verified by the signature verification device 6. This storage may be performed according to the designation of the user who operates the video reception device 3 or may be automatically performed by software in the video reception device 3.

FIG. 5 shows an example of a screen for the video receiving apparatus 3 to store the received video in the removable medium 21 according to the user's designation.
This screen is displayed on the video display device 11.
In the screen of this example, a saving range designation column 41, a folder name input column 42, and a save execution button 43 are displayed.
The user enters, for example, “January 1, 2007, 1: 1, 1 second” in the range designation field 41 for storing which part of the video data recorded in the recording medium 13 is to be stored in the removable medium 21. "--January 1, 1007 1: 7: 7" is entered and specified. Next, the user inputs and designates in the folder name input field 42 for storing where the video data is stored, for example, “E: ¥ Incident ¥”. Finally, when the user presses the save execution button 43, the save is executed.

The video display device 11 is a video display device having projection elements such as a television monitor, a CRT of a computer, and a liquid crystal monitor, for example, and has a function of displaying video by converting electricity into light.
Note that the video reception device 3 and the video display device 11 may be configured, for example, as a single device. As a specific example, a form incorporated in a television monitor, a form of a computer connected to a CRT, or a form of a portable terminal such as a mobile phone provided with a display device can be used.

  In addition, the video reception device 3 has an operation interface for instructing the video storage / delivery server 4 to perform playback, such as playback and fast forward. This interface can be configured from, for example, a GUI (Graphical User Interface) on a computer screen or a control panel terminal connected to the video reception device 3.

  The video storage / delivery server 4 is constituted by, for example, a personal computer (PC) having a built-in network interface and an interface to the recording medium 13, and has been transmitted from the video transmission device 2 or the signature generation device 5 via the network medium 7. In response to a video distribution request from the video receiving device 3 and a function for receiving the recorded video or the signed video and recording these videos on the connected recording medium 13, the video or signed video requested from the recording medium 13 is received. It has a function of taking out videos and distributing them to the video receiver 3 via the network medium 7.

  The recording medium 13 is a medium for recording a video such as a hard disk or a disk array, for example, and the video storage / delivery server 4 and a dedicated interface such as a SCSI (Small Computer System), ATA (AT Attachment), or FiberChannel, or , SAN (Storage Area Network), NAS (Network Attached Storage), and other interfaces using an IP network.

The removable media 21 includes, for example, a combination of optical media such as DVD-RAM, MO, and CD-RW and a drive, a hard disk mounted in a removable case, and a hard disk with a built-in removable interface such as USB and IEEE1394. And a medium having a function of storing video.
The removable media 21 is connected to the video reception device 3 or the signature verification device 6 with, for example, a dedicated interface such as SCSI, ATA, or FiberChannel, or an interface using an IP network such as SAN or NAS, or even while energizing such as USB or IEEE1394. Connected by a detachable interface.

  The signature verification device 6 is a decoder device that includes, for example, an image codec, an interface for outputting video to the video display device 12, and an interface to the removable media 21, and the video recorded in the removable media 21 is displayed on the video display device. 12 has a function of converting to a displayable form and outputting. For example, when the video display device 12 is a television monitor, the signature verification device 6 performs analog conversion. When the video is video data with a signature, the signature verification processing is performed using a predetermined key. I do. For example, when the video is a compressed video, the signature verification apparatus 6 performs an expansion process using an image codec.

The video display device 12 is a video display device having projection elements such as a television monitor, a computer CRT, and a liquid crystal monitor, for example, and has a function of displaying electricity by converting electricity into light.
Note that the signature verification device 6 and the video display device 12 may be configured, for example, as a single device. For example, the signature verification device 6 and the video reception device 3 may be configured as a single device.

FIG. 6 shows an example of a signature verification screen having a series of video playback functions and a signature verification function.
This screen is displayed on the video display device 12.
The screen of this example includes a video display field 51, a video operation button group 52 (in this example, the beginning, rewind, pause, playback, fast forward, end), a series of video data file designation fields 53, a signature A verification button 54 and verification result dialogs 55 and 56 are displayed.

The user designates video data (for example, “E: ¥ Incident ¥”) recorded on the removable medium 21 by a series of video data file designation fields 53 and reproduces the video data by operating the video operation button group 52. A series of videos displayed in the video display column 51 is browsed by performing rewinding, fast forwarding, and the like.
The user presses the signature verification button 54 when verifying the signature. Then, the signature verification device 6 performs signature verification of the data specified in the series of video data file specification fields 53, and, for example, a verification result for notifying the content “This video has not been tampered with” according to the verification result. A dialog 55 or a verification result dialog 56 notifying the content of “Warning: This video has been tampered with” is displayed.
Note that the signature verification may be automatically performed by the signature verification apparatus during playback or before playback, for example, without pressing a button.

The signature generation device 5 is a device having a built-in network interface, for example, generates a signature of the video received from the video transmission device 2 and transmits it (for example, a video with a signature) to the network medium 7. It has a function.
The signature generation apparatus 5 may be configured to generate a signature by simultaneously processing videos from a plurality of video transmission apparatuses 2.
For example, the signature generation device 5 and the video transmission device 2 may be configured as a single device. Further, for example, the signature generation device 5 and the video storage / delivery server 4 may be configured as a single device. Alternatively, for example, three devices of the signature generation device 5, the video transmission device 2, and the video storage / delivery server 4 may be configured as a single device.

Here, for convenience of explanation, FIG. 1 shows only one device 2, 3, and 5, but a plurality of these devices can be connected to the video storage / delivery server 4. is there.
The video storage / delivery server 4 simultaneously receives and records a plurality of different videos transmitted from a plurality of video transmission devices 2 or a plurality of signature generation devices 5, and in parallel, a plurality of video reception devices It is possible to simultaneously distribute a plurality of different arbitrary videos to 3.

In the video distribution system as described above, data called a key is required for the signature generation of the video data in the signature generation device 5 and the signature verification of the video data in the video reception device 3 and the video verification device 6.
Here, for signature generation and signature verification, a scheme such as a keyed-hashing for message authentication code (HMAC) that applies a common key cryptosystem that uses the same key for generation and verification may be used. A scheme such as a digital signature applying a public key cryptosystem using a different key for verification may be used.
In this example, a case where an RSA-PSS method, which is a kind of digital signature technology, is used for signature generation and signature verification will be described as an example.

A method capable of verifying the continuity of video will be described with reference to FIGS.
FIG. 2 schematically shows an example of the relationship between a series of videos and signatures in an example of a method that can verify video continuity.
Note that a is an integer of 2 or more.
In this example, the video data M4 _(a-1) at the end of the divided video data processed at the (a-1) th signature generation is used as the divided video data processed at the ath signature generation. Is the same as the _first video data M1 _(a) .
In this example, it is assumed that the divided video data is one JPEG frame.

This will be specifically described.
M1 _{(a-1) to} M4 _(a-1) are divided video data processed at the time of (a-1) signature generation, and M1 _{(a) to} M4 _(a) are , Divided video data to be processed at the time of a-th signature generation. Here, in this example, M _{1 (a)} = M _{4 (a−1)} . Similarly, in this example, M _{1 (a + 1)} = M _{4 (a)} , and so on.
h _{0,1 (a-1) to} h _{0,4 (a-1)} and h _{0,1 (a) to} h _{0,4 (a)} are respectively represented by M _{1 (a-1) to} M _{4 (} It is a hash value obtained by inputting _a-1) and M1 _{(a) to} M4 _(a) into the hash function h.

h _{1,1 (a-1)} is a hash value obtained by inputting the result of concatenating h _{0,1 (a-1)} and h _{0,2 (a-1)} to the hash function h.
_{Similarly, h 1,2 (a-1) is, h 0,3 (a-1)} and _{h 0,4 (a-1)} hash obtained by inputting the result of concatenating the hash function h to values It is.
H _{1,1 (a)} is a hash value obtained by inputting the result of concatenating h _{0,1 (a)} and h _{0,2 (a)} to the hash function h.
Similarly, h _{1,2 (a)} is a hash value obtained by inputting the result of concatenating h _{0,3 (a)} and h _{0,4 (a)} to the hash function h.

h _{2,1 (a-1)} is a hash value obtained by inputting the result of concatenating h _{1,1 (a-1)} and h _{1,2 (a-1)} to the hash function h.
Further, h _{2,1 (a)} is a hash value obtained by inputting the result of concatenating h _{1,1 (a)} and h _{1,2 (a)} to the hash function h.
The signature generation engine 31 calculates _a signature value σ _(a-1) from h _{2,1 (a-1)} and the secret key, and also calculates _a signature value σ _(a) from h _{2,1 (a)} and the secret key. Is calculated.

The video data M _{1 (a-1) to} M _{4 (a-1)} and M _{1 (a) to} M _{4 (a)} and signature values σ _(a-1) and σ _(a) are obtained from the signature generation device 5. Then, it is delivered to the video receiver 3 via the video storage / delivery server 4 or directly.
These pieces of information are further distributed from the video reception device 3 to the signature verification device 6. In addition, each hash value may be distributed in the same manner as the video data and the signature, if necessary, so that the video data stored arbitrarily extracted can be verified.
The same applies to signature generation after the (a + 1) th time.

At the time of signature verification, when the signature verification of M _{1 (a-1)} , M _{2 (a-1)} , M _{3 (a-1)} , and M _{1 (a)} is successful, the video data M _{1 (a-1)} , M2 _(a-1) , M3 _(a-1) , and M1 _(a) can be said to be continuous.
When the signature verification of M _{1 (a)} , M _{2 (a)} , M _{3 (a)} , M _{1 (a + 1)} is successful, the video data M _{1 (a)} , M _{2 (a)} , M _{3 ( a)} and M _{1 (a + 1)} can be said to be continuous.
And if these two continuity is confirmed, M1 _(a-1) , M2 _(a-1) , M3 _(a-1) , M1 _(a) , M2 _(a) , M It can be said that all of _{3 (a)} and M _{1 (a + 1)} are continuous.

FIG. 3 shows a flowchart of an example of processing performed by the signature generation apparatus 5 of this example.
First, in the initialization process (step S1), necessary memory allocation, variable initialization process, and the like are performed.
Next, in the counter value (i) count-up process (step S2), 1 is added to the variable i.
Next, in the process of receiving and storing the video data (M _i ) in the video buffer (step S3), the video data (M _i ) received from the video transmission device 2 is stored in the video buffer.

The hash value _{h 0, i} calculation processing of the video data _{(M i)} to generate a hash value _{h 0, i} of (step S4), and the video data of the video buffer which stores _{(M i).}
In the process of determining whether i has reached the number of messages to be processed at one signature generation (4 in this example) (step S5), i is 4 which is the number of messages to be processed at one signature generation. Branch depending on whether or not there is. Specifically, if i has not reached 4, the process branches to the counter value (i) count-up process (step S2). If i has reached 4, the counter value (i) is set to 1. The process branches to the process (step S6).

In the process of setting the counter value (i) to 1 (step S6), 1 is stored in the variable i.
Next, in the hash value h _1,1 calculation process of the concatenated value of h _0,1 and h _0,2 (step S7), the concatenation of the hash value h _0,1 and h _0,2 calculated in the process of step S4 is performed. The hash value h _1,1 of the value is calculated.
Next, in the hash value h _1,2 calculation process of the concatenated value of h _0,3 and h _0,4 (step S8), the concatenation of the hash value h _0,3 and h _0,4 calculated in the process of step S4 is performed. The hash value h _1,2 of the value is calculated.
Next, in the hash value h _2,1 calculation process of the concatenated value of h _1,1 and h _1,2 (step S9), the hash values h _1,1 and h _1, calculated in the processes of step S7 and step S8 _. It calculates a hash value _{h 2,1} the _second coupling values.

Next, in the signature (σ) generation process (step S10), the signature (σ) is generated by inputting the h ₂ , ₁ and the secret key calculated in step S9 to the signature engine 31.
Next, in the signature (σ) distribution process (step S11), the signature (σ) is distributed to the video accumulation / delivery server 4 or the like. At this time, in this example, the video is also distributed at the same time. However, as another configuration example, the video storage / delivery server 4 may receive the video directly from the video transmission device 2. Further, the hash value may be distributed simultaneously.

In the process of clearing and M ₄ in the video buffer other than M ₄ as a new M ₁ (step S12), the instead of clearing all of the video buffer, and clears the video buffer other than M _4, the M ₄ held in the memory as a new M _1. As a result, only the new M ₁ is held in the memory, and the new M _{2 to} M ₄ wait for storage.
In the video reception end determination process (step S13), the presence / absence of a video to be received is confirmed. If there is a video to be received, the process branches to the counter value (i) count-up process (step S2) and is received. If there is no video to be processed, the process branches to an end process (step S14).
In the end process (step S14), a process necessary to end the process such as releasing the secured memory is performed.

FIG. 4 shows a flowchart of an example of processing performed by the signature verification apparatus 6 of this example.
For convenience of explanation, in FIG. 4, the same processes as those shown in FIG. 3 are denoted by the same reference numerals.

First, in the initialization process (step S1), necessary memory allocation, variable initialization process, and the like are performed.
Next, in the counter value (i) count-up process (step S2), 1 is added to the variable i.
Next, in the process of reading the video data (M _i ) and storing it in the video buffer (step S 21), the video data (M _i ) is read from the removable medium 21 connected to the signature verification device 6 and stored in the video buffer. .

The hash value _{h 0, i} calculation processing of the video data _{(M i)} to generate a hash value _{h 0, i} of (step S4), and the video data of the video buffer which stores _{(M i).}
In the process of determining whether i has reached the number of messages to be processed at one signature generation (4 in this example) (step S5), i is 4 which is the number of messages to be processed at one signature generation. Branch depending on whether or not there is. Specifically, if i has not reached 4, the process branches to the counter value (i) count-up process (step S2). If i has reached 4, the counter value (i) is set to 1. The process branches to the process (step S6).

In the process of setting the counter value (i) to 1 (step S6), 1 is stored in the variable i.
Next, in the hash value h _1,1 calculation process of the concatenated value of h _0,1 and h _0,2 (step S7), the concatenation of the hash value h _0,1 and h _0,2 calculated in the process of step S4 is performed. The hash value h _1,1 of the value is calculated.
Next, in the hash value h _1,2 calculation process of the concatenated value of h _0,3 and h _0,4 (step S8), the concatenation of the hash value h _0,3 and h _0,4 calculated in the process of step S4 is performed. The hash value h _1,2 of the value is calculated.
Next, in the hash value h _2,1 calculation process of the concatenated value of h _1,1 and h _1,2 (step S9), the hash values h _1,1 and h _1, calculated in the processes of step S7 and step S8 _. It calculates a hash value _{h 2,1} the _second coupling values.

In the signature (σ) reading process (step S22), the signature (σ) is read from the removable medium 21 connected to the signature verification device 6.
Next, in the signature verification processing from the signature (σ) and the hash value h _2,1 (Step S23), the signature (σ), the hash value h _2,1 and the public key are input, and the success or failure of signature verification is returned.

In the process of clearing and M ₄ in the video buffer other than M ₄ as a new M ₁ (step S12), the instead of clearing all of the video buffer, and clears the video buffer other than M _4, the M ₄ held in the memory as a new M _1. As a result, only the new M ₁ is held in the memory, and the new M _{2 to} M ₄ wait for storage.

  In the video reading end determination process (step S24), it is determined from the removable media 21 connected to the signature verification device 6 whether there is a video to be read next. If there is a video to be read next, the process branches to a counter value (i) count-up process (step S2). If there is no video to be read next, the process branches to a verification result display process (step S25).

In the verification result display processing (step S25), the success or failure of the signature verification output in the signature verification processing (step S23) is displayed on the video display device 12 of the signature verification device 6.
Specifically, for example, as shown in FIG. 6, a verification result dialog 55 is displayed if the signature verification is successful, and a verification result dialog 56 is displayed if the signature verification is unsuccessful.
In the end process (step S14), a process necessary to end the process such as releasing the secured memory is performed.

Here, the process of clearing and M ₄ in the video buffer other than M ₄ described above a new M ₁ for (step S12) as another configuration example, instead of the M ₄ as a new M _1, the hash value of M ₄ a structure may be employed that a new M _1.
In this case, when the video data (M ₁ ) is read in the process of reading the video data (M _i ) and storing it in the video buffer (step S 21) at the time of signature verification, the hash value of M ₁ is calculated and the next The hash value h _{0, i} calculation processing (step S4) of the video data (M _i ) is performed. In the hash value h _{0, i} calculation process (step S4) of the video data (M _i ), when i is 1, the hash value of the calculated M ₁ is not calculated but the hash value of the video data M _i is calculated. Is calculated as h _0,1 .
Thus, there are cases where the memory usage can be reduced by handling the hash value of the video data instead of the video data having a large data size.

In this example, the case where one frame of JPEG is used as the divided video data has been described. However, as another configuration example, one packet when video is transmitted to the network medium 7 may be used. Alternatively, a unit such as MPEG (Moving Picture Experts Group) GOV (Group Of Video Object Plane) may be used.
In this example, the case where the present invention is applied to video data has been shown. However, for example, the present invention can be applied not only to video data but also to audio data and other metadata accompanying video.

As described above, in this example, for a series of videos that can be divided into a plurality of video data, a plurality of consecutive divided video data M ₁ , M _{2 ,.} For n (n is an integer of 2 or more), hash values h (M ₁ ), h (M ₂ ),..., H (M _n ) are calculated using a predetermined hash function, and these hashes are calculated. One hash value is generated from all of the values h (M ₁ ), h (M ₂ ),..., H (M _n ) using a predetermined process and a hash function, and the one hash value the signature value calculated for the video data M _i, which are each divided _{(i = 1,2, ···, n} ) in the method of generating a signature S _i with respect to said single hash value to The signature value calculation process is repeated t (t is an integer of 2 or more) times. , A series of image _{M 1 (1), M 2} (1), ···, M n (1), M 1 (2), M 2 (2), ···, M n (2), ·· .., M _{1 (t)} , M _{2 (t)} ,..., M _{n (t)} from the signature generation device 5 and the video data and signature of a part or all of a series of videos In a video distribution system (an example of a video signature system) including a signature verification device 6 that performs signature verification, the divided video data M _{1 (a )} , M _{2 (a)} ,..., M _{n (a)} , M _{1 (a)} is data associated with M _{n (a−1)} , so that in the signature verification apparatus 6, (A-1) The continuity between the first signature and the a-th signature can be verified.

In one _{construction, M 1} is a data associated with _{M n (a-1)} a _(a), to divide video data _{M n} and _(a-1) the same image data.
As another configuration example, M ₁ is a data associated with M n _(a-1) a _(a), and enter the divided video data M _n of _(a-1) to a predetermined hash function to obtain The hash value that is the result obtained.
Therefore, in this example, the continuity of the video can be verified beyond the scope of one signature generation.

Note that in the signature generation apparatus 5 in the video distribution system of this example (an example of the video signature system), taking FIG. 2 as an example, M _{1 (a)} = M _{4 (a-1)} and a predetermined number (this example) In this case, hash values h _{0,1 (a) to} h _{0,4 (a)} are obtained by using a hash function h for each of M _{1 (a) to} M _{4 (a)} which are four pieces of video data. The initial hash value calculation means is constituted by the function to calculate, and the processing shown in FIG. 2 using these predetermined number of hash values h _{0,1 (a) to} h _{0,4 (a)} and the hash function h. A final hash value acquisition unit is configured by the function of acquiring one hash value h _{2,1 (a) according} to the procedure, and the signature generation engine 31 for this one hash value h _{2,1 (a)} . function by the signature generating means for generating a signature sigma _(a) the configuration It has been.
Further, in the signature verification apparatus 6 in the video distribution system (an example of the video signature system) of this example, the first unit is configured by the same function as the initial hash value calculation unit, and by the same function as the final hash value acquisition unit. The second means is configured and has a function of performing signature verification using one hash value h _{2,1 (a)} acquired thereby and the signature σ _(a) generated by the signature generation device 5 Signature verification means is configured.

Here, the configuration of the system and apparatus according to the present invention is not necessarily limited to the configuration described above, and various configurations may be used. The present invention can also be provided as, for example, a method or method for executing the processing according to the present invention, a program for realizing such a method or method, or a recording medium for recording the program. It is also possible to provide various systems and devices.
The application field of the present invention is not necessarily limited to the above-described fields, and the present invention can be applied to various fields.
In addition, as various processes performed in the system and apparatus according to the present invention, for example, the processor executes a control program stored in a ROM (Read Only Memory) in hardware resources including a processor and a memory. A controlled configuration may be used, and for example, each functional unit for executing the processing may be configured as an independent hardware circuit.
The present invention can also be understood as a computer-readable recording medium such as a floppy (registered trademark) disk or a CD (Compact Disc) -ROM storing the control program, and the program (itself). The processing according to the present invention can be performed by inputting the program from the recording medium to the computer and causing the processor to execute the program.

It is a figure which shows the structural example of the video delivery system which concerns on one Example of this invention. It is a figure which shows typically an example of the relationship of a series of image | video and signature based on one Example of this invention. It is a figure which shows an example of the procedure of the process performed by the signature production | generation apparatus which concerns on one Example of this invention. It is a figure which shows an example of the procedure of the process performed by the signature verification apparatus which concerns on one Example of this invention. It is a figure which shows an example of the screen which preserve | saves the received image | video on removable media. It is a figure which shows an example of the signature verification screen which has a series of video reproduction functions and a signature verification function. It is a figure which shows typically an example of the relationship between a series of images and a signature according to the background art. It is a figure which shows an example of the procedure of the process performed by the signature production | generation apparatus which concerns on background art. It is a figure which shows an example of the procedure of the process performed by the signature verification apparatus which concerns on background art.

Explanation of symbols

  1 .... Video generation device, 2 .... Video transmission device, 3 .... Video reception device, 4 .... Video storage and delivery server, 5 .... Signature generation device, 6 .... Signature verification device, 7 .... Network medium, 11 12 .. Video display device 13.. Recording medium 21.. Removable media 31. Signature generation engine 41. Range selection field to be saved 42. Folder name input field to be saved 43. Execution button 51 .. Video display field 52. Video operation button group 53. Series of video data file designation field 54. Signature verification button 55 55 56 Verification result dialog

Claims (2)

In a video signature system having a signature generation apparatus that generates a signature for a series of videos, and a signature verification apparatus that performs signature verification using part or all of the series of videos and the signature,
The signature generation apparatus is configured to (a-1) a predetermined number of signatures for a (a is an integer of 2 or more) signatures for a plurality of continuous video data obtained by dividing the series of videos. The data related to the predetermined number of video data at the end of the data is the first data at the top, and (predetermined number −1) continuous video data following the end video data are Initial hash value calculating means for calculating a hash value using a predetermined hash function for each of the predetermined number of pieces of data as the second to predetermined number of pieces of data;
Final hash value acquisition means for acquiring one hash value by a predetermined processing procedure using the predetermined number of hash values calculated by the initial hash value calculation means and a predetermined hash function;
Signature generating means for generating a signature for the hash value acquired by the final hash value acquiring means,
The signature verification apparatus includes a first unit having the same function as the initial hash value calculation unit;
Second means having the same function as the final hash value acquisition means;
Signature verification means for performing signature verification using the hash value acquired by the second means and the signature;
A video signature system characterized by comprising: The video signature system according to claim 1,
In the a-th signature, the initial hash value calculation means ends the end of a predetermined number of pieces of data in which the (a-1) -th signature is performed for a plurality of continuous video data obtained by dividing the series of videos. A hash value obtained by inputting the end video data itself or the end video data to a predetermined hash function when the data related to the predetermined number of video data is the first data at the top. Is the first data,
A video signature system characterized by that.

Images