Content generation device, method for controlling content generation device, and program

Abstract

To provide a content generation device that can guarantee the authenticity of the generation time of content.SOLUTION: A digital camera 100 includes an authenticity guarantee mode for guaranteeing the authenticity of content. The digital camera 100, when receiving an instruction to change the authenticity guarantee mode from a disabled state to an enabled state and receiving an instruction to generate an image file, generates an image file 600 including the photographing date and time based on an already set reference time by using externally received time information.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a content generation device, a control method for a content generation device, and a program. [Background technology]

[0002] In recent years, information sharing via the Internet has become very popular, and anyone can publish and transmit various information to an unspecified number of people. It has also become possible to perform various types of processing on digital images. In this situation, information may be sent from an unreliable source, or published information may have been illegally tampered with, so there is a demand for technology to guarantee the authenticity of published and transmitted information.

[0003] For example, the technology disclosed in Patent Document 1 has been proposed as a technology for guaranteeing the authenticity of information that is made public or transmitted. In Patent Document 1, a digital camera has a function for adding data for verifying the originality of image data, specifically, a hash value of the image data including the image itself and additional information such as the date and time the image was taken, to an image file that contains the image data obtained by shooting. This makes it possible to use the hash value added to the image file to determine whether the image data included in the image file has been changed since it was shot. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2008-5421 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the technology of Patent Document 1, a photographer can manually change the time setting of a digital camera to any time, and easily fake the shooting date and time of image data. Thus, in the past, it was not possible to guarantee the authenticity of the generation time of content generated by a content generating device such as a digital camera.

[0006] An object of the present invention is to provide a content generation device, a control method for a content generation device, and a program that can guarantee the authenticity of the generation time of content. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the content generation device of the present invention comprises a means for receiving an instruction to generate content from a user, a means for receiving an instruction from the user to change an authenticity assurance mode for guaranteeing authenticity of the content to enabled or disabled, and a control means for controlling the generation of the content, and is characterized in that when an instruction to change the authenticity assurance mode from disabled to enabled and an instruction to generate the content are received, the control means generates the content including a generation time of the content based on a reference time that has been adjusted using time information received from outside. Effect of the Invention

[0008] According to the present invention, it is possible to guarantee the authenticity of the content generation time. [Brief description of the drawings]

[0009] [Figure 1] 1 is an external view of a digital camera serving as a content generation device according to an embodiment of the present invention. [Diagram 2] 2 is a block diagram showing an example of the configuration of the digital camera shown in FIG. 1. [Diagram 3] 4 is a flowchart showing the procedure of a shooting control process executed by the digital camera of FIG. [Figure 4]FIG. 2 is a diagram showing an example of a screen displayed on the display unit in FIG. [Diagram 5] 4 is a flowchart showing the procedure of the photographing process in S318 of FIG. 3. [Figure 6] 2 is a diagram showing an example of an image file generated by the digital camera of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner.

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a content generating device of the present invention is applied to a digital camera capable of taking still images and recording moving images will be described in detail below with reference to the accompanying drawings.

[0012] First, the configuration and functions of a digital camera 100 serving as a content generation device according to the present embodiment will be described with reference to FIGS.

[0013] Fig. 1(a) is a front perspective view of the digital camera 100 with the lens unit 150 removed. Fig. 1(b) is a rear perspective view of the digital camera 100.

[0014] 1, the display unit 28 is an outside-finder display unit that displays images and various information, and is a display device such as an LCD provided on the rear surface of the camera body. The display unit 28 is provided with a touch panel 70a. The touch panel 70a is a touch operation member that can detect contact (touch operation) with the display surface (touch operation surface) of the display unit 28.

[0015] The outside viewfinder display unit 43 is a display unit provided on the top surface of the digital camera 100, and displays various settings of the digital camera 100, including the shutter speed and aperture. The shutter button 61 is an operation member for issuing a shooting instruction. The mode change switch 60 is an operation member for switching between various modes. The terminal cover 40 is a cover that protects a connector (not shown) for a connection cable or the like that connects the digital camera 100 to an external device.

[0016] The main electronic dial 71 is a rotary operation member, and by turning this main electronic dial 71, settings such as shutter speed and aperture can be changed. The power switch 72 is an operation member that switches the power of the digital camera 100 between ON and OFF. The sub electronic dial 73 is a rotary operation member, and by turning this sub electronic dial 73, the selection frame (cursor) can be moved, images can be forwarded, and the like. The four-way key 74 is configured so that the up, down, left, and right parts can each be pressed, and processing can be performed according to the part of the four-way key 74 that is pressed. The SET button 75 is a push button, and is mainly used to confirm a selection item, etc.

[0017] The video button 76 is used to start or stop video shooting (recording). The AE lock button 77 is a push button, and pressing the AE lock button 77 in a shooting standby state fixes the exposure state. The enlargement button 78 is an operation button for switching the enlargement mode ON and OFF in the live view display (LV display) in the shooting mode. By turning the enlargement mode ON and then operating the main electronic dial 71, the live view image (LV image) can be enlarged or reduced. In the playback mode, the enlargement button 78 functions as an operation button for enlarging the playback image or increasing its magnification. The playback button 79 is an operation button for switching between the shooting mode and the playback mode. By pressing the playback button 79 during the shooting mode, the mode is switched to the playback mode, and the latest image among the images recorded in the recording medium 200 in FIG. 2 described later can be displayed on the display unit 28. The menu button 81 is a push button used to perform an instruction operation for displaying a menu screen, and when the menu button 81 is pressed, a menu screen on which various settings can be made is displayed on the display unit 28. The user can intuitively make various settings using the menu screen displayed on the display unit 28, the four-way key 74, and the SET button 75.

[0018] The touch bar 82 (multifunction bar: M-Fn bar) is a line-shaped touch operation member (line touch sensor) capable of receiving touch operations. The touch bar 82 is disposed at a position where it can be touched (touched) by the thumb of the right hand when the grip part 90 is held in the right hand (held with the little finger, ring finger, and middle finger of the right hand) so that the shutter button 61 can be pressed with the index finger of the right hand. That is, the touch bar 82 is disposed at a position where it can be operated when the eyepiece part 16 is placed close to the viewfinder and the user is in a position (shooting posture) so that the shutter button 61 can be pressed at any time. The touch bar 82 is a reception part that can receive tap operations (operations of touching and releasing without moving within a predetermined period) and left and right slide operations (operations of touching and then moving the touch position while keeping the touch) on the touch bar 82. The touch bar 82 is an operation member different from the touch panel 70a and does not have a display function.

[0019] The communication terminal 10 is a communication terminal for the digital camera 100 to communicate with the lens unit 150 in FIG. 2, which will be described later. The eyepiece 16 is an eyepiece for the eyepiece finder 17 (a peer-in type finder). A user can view an image displayed on an internal EVF 29 (Electronic View Finder) in FIG. 2, which will be described later, through the eyepiece 16. The eyepiece detection unit 57 is an eyepiece detection sensor that detects whether a user (photographer) has placed his / her eye on the eyepiece 16. The lid 202 is a lid for a slot that stores a recording medium 200 in FIG. 2, which will be described later. The grip unit 90 is a holding unit that is shaped so that the user can easily hold it with the right hand when holding the digital camera 100. The shutter button 61 and the main electronic dial 71 are located at positions that can be operated with the index finger of the right hand when the digital camera 100 is held by gripping the grip unit 90 with the little finger, ring finger, and middle finger of the right hand. In the same state, the sub electronic dial 73 and touch bar 82 are disposed at positions that can be operated with the thumb of the right hand. The thumb rest section 91 (thumb standby position) is a grip member provided on the rear side of the digital camera 100 at a position where it is easy to place the thumb of the right hand that is holding the grip section 90 when none of the operation members are being operated. The thumb rest section 91 is made of a rubber member or the like to enhance holding power (grip feeling).

[0020] FIG. 2 is a block diagram showing an example of the configuration of the digital camera 100 in FIG. 1. In FIG. 2, the lens unit 150 is a lens unit equipped with an interchangeable photographing lens, and is detachable from the digital camera 100. The lens 103 is usually composed of a plurality of lenses, but is shown here as a single lens for simplicity. The communication terminal 6 is a communication terminal through which the lens unit 150 communicates with the digital camera 100, and the communication terminal 10 is a communication terminal through which the digital camera 100 communicates with the lens unit 150. The lens unit 150 communicates with the system control unit 50 via these communication terminals 6 and 10. The lens unit 150 controls the aperture 1 via the aperture drive circuit 2 by the internal lens system control circuit 4. The lens unit 150 adjusts the focus by displacing the position of the lens 103 via the AF drive circuit 3 by the lens system control circuit 4.

[0021] The shutter 101 is a focal plane shutter that can freely control the exposure time of the imaging unit 22 under the control of the system control unit 50 .

[0022] The imaging unit 22 is an image sensor configured with an imaging element such as a CCD or a CMOS that converts an optical image into an electrical signal. The imaging unit 22 may include an imaging surface phase difference sensor that outputs defocus amount information to the system control unit 50. The A / D converter 23 converts the analog signal output from the imaging unit 22 into a digital signal.

[0023] The image processing unit 24 performs predetermined processing (pixel interpolation, resizing such as reduction, color conversion, etc.) on the data from the A / D converter 23 or the data from the memory control unit 15. The image processing unit 24 also performs predetermined arithmetic processing using the captured image data, and the system control unit 50 performs exposure control and distance measurement control based on the arithmetic results obtained by the image processing unit 24. This allows TTL (through-the-lens) type AF (autofocus) processing, AE (autoexposure) processing, EF (flash pre-flash) processing, etc. to be performed. The image processing unit 24 further performs predetermined arithmetic processing using the captured image data, and performs TTL type AWB (auto white balance) processing based on the obtained arithmetic results.

[0024] The output data from the A / D converter 23 is written to the memory 32 via the image processing unit 24 and the memory control unit 15. Alternatively, the output data from the A / D converter 23 is written to the memory 32 via the memory control unit 15 without going through the image processing unit 24. The memory 32 stores image data obtained by the imaging unit 22 and converted into digital data by the A / D converter 23, and image data to be displayed on the display unit 28 and EVF 29. The memory 32 has a storage capacity sufficient to store a predetermined number of still images, a predetermined period of moving images, and audio.

[0025] The memory 32 also serves as a memory (video memory) for image display. The D / A converter 19 converts the image display data stored in the memory 32 into an analog signal and supplies it to the display unit 28 or the EVF 29. The image data for display written in the memory 32 is displayed on the display unit 28 or the EVF 29 via the D / A converter 19. The display unit 28 and the EVF 29 perform display according to the analog signal from the D / A converter 19. A digital signal that has been A / D converted by the A / D converter 23 and stored in the memory 32 is converted into an analog signal in the D / A converter 19, and the analog signal is sequentially transferred to and displayed on the display unit 28 or the EVF 29, thereby performing a live view display (LV). Hereinafter, an image displayed in the live view display is referred to as a live view image (LV image).

[0026] The system control unit 50 is a control unit consisting of at least one processor and / or at least one circuit, and controls the entire digital camera 100. The system control unit 50 is both a processor and a circuit. The system control unit 50 executes programs recorded in the non-volatile memory 56 to realize each process of this embodiment, which will be described later. The system control unit 50 also performs display control by controlling the memory 32, the D / A converter 19, the display unit 28, the EVF 29, etc.

[0027] The system memory 52 is, for example, a RAM. The system control unit 50 loads constants and variables for the operation of the system control unit 50, programs read from the non-volatile memory 56, and the like, in the system memory 52.

[0028] The non-volatile memory 56 is an electrically erasable and recordable memory, such as an EEPROM. Constants, programs, and the like for operating the system control unit 50 are recorded in the non-volatile memory 56. The programs referred to here are programs for executing various flowcharts described later in this embodiment.

[0029] The system timer 53 is a timing unit that measures the time used for various controls and the time of a built-in clock.

[0030] The communication unit 54 transmits and receives video signals and audio signals to and from an external device connected wirelessly or via a wired cable. The communication unit 54 can also connect to a wireless LAN (Local Area Network) or the Internet. The communication unit 54 can also communicate with an external device via Bluetooth (registered trademark) or Bluetooth Low Energy. The communication unit 54 can transmit images (including LV images) captured by the imaging unit 22 and images recorded in the recording medium 200, and can also receive various information such as image data and a video recording start instruction from an external device. When the communication unit 54 receives a video recording start instruction from an external device, it can notify the user of the receipt of the instruction by causing the light-emitting unit 102 to light up or by generating an electronic sound from the speaker 92. Examples of external devices with which the communication unit 54 communicates include a smartphone, a tablet terminal, and a desktop PC.

[0031] The attitude detection unit 55 detects the attitude of the digital camera 100 with respect to the direction of gravity. Based on the attitude detected by the attitude detection unit 55, it is possible to determine whether the image captured by the imaging unit 22 was captured with the digital camera 100 held horizontally or vertically. The system control unit 50 can add orientation information corresponding to the attitude detected by the attitude detection unit 55 to the image file of the image captured by the imaging unit 22, or rotate and record the image. An acceleration sensor, a gyro sensor, or the like can be used as the attitude detection unit 55. It is also possible to detect the movement of the digital camera 100 (panning, tilting, lifting, whether it is stationary, etc.) using the acceleration sensor or gyro sensor that is the attitude detection unit 55.

[0032] The eyepiece detection unit 57 is an eyepiece detection sensor that detects the approach (approach) and departure (away) of an eye (object) to the eyepiece unit 16 of the eyepiece finder 17. The system control unit 50 switches between display (display state) / non-display (non-display state) of the display unit 28 and the EVF 29 according to the state detected by the eyepiece detection unit 57. More specifically, at least in a shooting standby state and when the display destination switching setting is automatic switching, when the eye is not placed in contact with the camera, the display is turned on as the display unit 28 and the EVF 29 is not displayed. Also, when the eye is placed in contact with the camera, the display is turned on as the display unit 29 and the display is not displayed. For example, an infrared proximity sensor can be used as the eyepiece detection unit 57, and it can detect the approach of an object to the eyepiece unit 16 of the eyepiece finder 17 incorporating the EVF 29. When an object approaches, infrared light projected from a light projecting section (not shown) of the eyepiece detection section 57 is reflected by the object and received by a light receiving section (not shown) of the infrared proximity sensor. The amount of infrared light received can also determine how close the object is to the eyepiece section 16 (eyepiece distance). In this way, the eyepiece detection section 57 performs eyepiece detection to detect the proximity of the object to the eyepiece section 16. When an object is detected approaching within a predetermined distance from the non-eyepiece state (non-approaching state), it is detected that the object has been placed in eye contact. When an object whose approach was detected moves away from the eyepiece state (approaching state) by a predetermined distance or more, it is detected that the object has been removed. The threshold value for detecting eye contact and the threshold value for detecting removal of the eye may be different, for example, by providing a hysteresis. In addition, after the eye is detected, the eye is in the eye contact state until removal of the eye is detected. After the removal of the eye is detected, the eye is in the non-eye contact state until removal of the eye is detected. The infrared proximity sensor is just an example, and other sensors may be used for eye proximity detection unit 57 as long as they can detect a state that can be regarded as eye proximity.

[0033] The GPS receiver 119 receives GPS signals including location information and time information from GPS satellites (artificial satellites). Based on the GPS signals received by the GPS receiver 119, the digital camera 100 specifies the location of the digital camera 100 and adjusts the reference time of the digital camera 100. The digital camera 100 can add information indicating the specified location and a shooting date and time based on the adjusted reference time to a captured image.

[0034] The hash value generation unit 210 executes a hash function on the image file to generate (calculate) a hash value. Note that the system control unit 50, instead of the hash value generation unit 210, may generate the hash value.

[0035] Various settings of the camera, including the shutter speed and aperture, are displayed on the outside viewfinder display section 43 via an outside viewfinder display section drive circuit 44 .

[0036] The power supply control unit 80 is composed of a battery detection circuit, a DC-DC converter, a switch circuit for switching between blocks to which electricity is applied, and the like, and detects whether a battery is attached, the type of battery, and the remaining battery power, etc. The power supply control unit 80 also controls the DC-DC converter based on the detection results and instructions from the system control unit 50, and supplies the necessary voltage for the necessary period to each unit including the recording medium 200. The power supply unit 30 is composed of primary batteries such as alkaline batteries and lithium batteries, secondary batteries such as NiCd batteries, NiMH batteries, and Li batteries, an AC adapter, etc.

[0037] The recording medium I / F 18 is an interface with a recording medium 200 such as a memory card or a hard disk. The recording medium 200 is a recording medium such as a memory card for recording captured images, and is composed of a semiconductor memory, a magnetic disk, or the like.

[0038] The operation unit 70 is an input unit that accepts operations from the user, and is used to input various operational instructions to the system control unit 50. As shown in Fig. 2, the operation unit 70 includes a shutter button 61, a mode changeover switch 60, a power switch 72, a touch panel 70a, other operation members 70b, etc. The other operation members 70b include a main electronic dial 71, a sub electronic dial 73, a four-way key 74, a SET button 75, a video button 76, an AE lock button 77, a magnification button 78, a playback button 79, a menu button 81, a touch bar 82, etc.

[0039] The shutter button 61 includes a first shutter switch 62 and a second shutter switch 64. The first shutter switch 62 is turned on when the shutter button 61 is pressed halfway (a shooting preparation instruction) during operation of the shutter button 61, and generates a first shutter switch signal SW1. In response to the first shutter switch signal SW1, the system control unit 50 starts shooting preparation operations such as AF processing, AE processing, AWB processing, and EF processing.

[0040] The second shutter switch 64 is turned on when the shutter button 61 is fully pressed (photographing instruction) and generates a second shutter switch signal SW2. The system control unit 50 starts a series of photographing processing operations, from reading out a signal from the imaging unit 22 to writing the captured image to the recording medium 200 as an image file, based on the second shutter switch signal SW2.

[0041] The mode changeover switch 60 changes the operation mode of the system control unit 50 to one of a still image shooting mode, a video shooting mode, a playback mode, etc. Modes included in the still image shooting mode include an auto shooting mode, an auto scene determination mode, a manual mode, an aperture priority mode (Av mode), a shutter speed priority mode (Tv mode), and a program AE mode (P mode). In addition, there are various scene modes and custom modes that are shooting settings according to shooting scenes. The mode changeover switch 60 allows the user to directly switch to one of these modes. Alternatively, after switching to a list screen of shooting modes with the mode changeover switch 60, the user may selectively switch to one of the displayed modes using another operating member. Similarly, the video shooting mode may also include a plurality of modes.

[0042] The touch panel 70a is a touch sensor that detects various touch operations on the display surface of the display unit 28 (the operation surface of the touch panel 70a). The touch panel 70a and the display unit 28 can be configured as one unit. For example, the touch panel 70a is configured so that the light transmittance does not interfere with the display of the display unit 28, and is attached to the upper layer of the display surface of the display unit 28. Then, input coordinates on the touch panel 70a are associated with display coordinates on the display surface of the display unit 28. This makes it possible to provide a GUI (Graphical User Interface) that makes it seem as if the user can directly operate the screen displayed on the display unit 28.

[0043] The system control unit 50 can detect the following operations or states on the touch panel 70a.

[0044] A finger or pen that has not been touching the touch panel 70a touches the touch panel 70a again, that is, the start of touching (hereinafter referred to as touch-down).

[0045] The touch panel 70a is in a state of being touched with a finger or a pen (hereinafter, referred to as Touch-On).

[0046] A finger or a pen is moved while touching the touch panel 70a (hereinafter referred to as Touch-Move).

[0047] The finger or pen that has been touching the touch panel 70a is removed (released) from the touch panel 70a, that is, the end of touch (hereinafter referred to as touch-up).

[0048] Nothing is being touched on the touch panel 70a (hereinafter, referred to as Touch-Off).

[0049] When touch-down is detected, touch-on is also detected at the same time. After touch-down, touch-on will usually continue to be detected unless touch-up is detected. If touch-move is detected, touch-on will also be detected at the same time. Even if touch-on is detected, touch-move will not be detected if the touch position does not move. After it is detected that all fingers or pens that were touching have touched up, touch-off will occur.

[0050] These operations and states, as well as the position coordinates of the touch panel 70a touched by a finger or pen, are notified to the system control unit 50 via the internal bus. The system control unit 50 then determines what kind of operation (touch operation) was performed on the touch panel 70a based on the notified information. For touch moves, the direction of movement of the finger or pen moving on the touch panel 70a can also be determined for each vertical and horizontal component on the touch panel 70a based on the change in position coordinates. If a touch move of a predetermined distance or more is detected, it is determined that a slide operation has been performed. An operation in which a finger is touched on the touch panel 70a, quickly moved a certain distance, and then released is called a flick. In other words, a flick is an operation in which a finger is quickly traced on the touch panel 70a as if flicking it. If a touch move of a predetermined distance or more at a predetermined speed or more is detected and a touch up is detected immediately, it can be determined that a flick has been performed (it can be determined that a flick has occurred following a slide operation). Furthermore, a touch operation in which multiple points (for example, two points) are touched together (multi-touch) and the touch positions are brought closer together is called pinch in, and a touch operation in which the touch positions are moved away from each other is called pinch out. Pinch out and pinch in are collectively called pinch operations. The touch panel 70a may be of any of various touch panel types, such as a resistive film type, a capacitive type, a surface acoustic wave type, an infrared type, an electromagnetic induction type, an image recognition type, and an optical sensor type. There are types that detect a touch by contact with the touch panel, and types that detect a touch by the approach of a finger or a pen to the touch panel, and either type may be used.

[0051] Next, a description will be given of shooting when the digital camera 100 has set the authenticity assurance mode to be active. In this embodiment, when shooting is performed with the authenticity assurance mode enabled, the image file generated by the shooting contains the history information 603 in Fig. 6, which will be described later. On the other hand, when shooting is performed with the authenticity assurance mode disabled, the image file generated by the shooting does not contain the history information 603 in Fig. 6, which will be described later. In this embodiment, it is possible to determine whether malicious tampering has occurred based on whether the hash value or signature value included in this history information 603 has been changed.

[0052] FIG. 3 is a flowchart showing the procedure of the photographing control process executed by the digital camera 100 of FIG. 1. The photographing control process of FIG. 3 is a series of processes from when the digital camera 100 sets the authenticity assurance mode to be active in accordance with an instruction received from the user until the photographing is completed. It is assumed that, at the start of the photographing control process of FIG. 3, the authenticity assurance mode is set to be inactive in the digital camera 100, and the setting screen of FIG. 4(a) is displayed on the display unit 28. The setting screen of FIG. 4(a) is a screen for the user to instruct to change the authenticity assurance mode to be active or inactive. The photographing control process of FIG. 3 is realized by the system control unit 50 expanding a program stored in the nonvolatile memory 56 into the system memory 52 and executing it when the power switch 72 is turned on.

[0053] 3, first, in step S301, the system control unit 50 determines whether or not an instruction to change the authenticity assurance mode to active is given on the setting screen of Fig. 4(a). The system control unit 50 waits until an instruction to change the authenticity assurance mode to active is given on the setting screen of Fig. 4(a), and when an instruction to change the authenticity assurance mode to active is given (YES in S301), the shooting control process proceeds to S302.

[0054] In S302, the system control unit 50 determines whether or not the digital camera 100 has a GPS receiving function. For example, if the digital camera 100 does not have a GPS receiving unit 119 or if a GPS accessory is not connected to the digital camera 100, it is determined that the digital camera 100 does not have a GPS receiving function. The GPS accessory is an attached part for extending the GPS receiving function of the digital camera 100, and the process of the GPS accessory receiving GPS signals from GPS satellites is controlled by the system control unit 50. In this case, the shooting control process proceeds to S303.

[0055] In S303, the system control unit 50 determines whether or not a GPS receiver is connected to the digital camera 100. The GPS receiver is a communication device equipped with a GPS receiving function, such as a smartphone, tablet terminal, or PC, and the process of receiving GPS signals from GPS satellites by this communication device is controlled by the control unit of this communication device. If it is determined that a GPS receiver is not connected to the digital camera 100, the shooting control process proceeds to S304.

[0056] In S304, the system control unit 50 displays the notification screen of Fig. 4(b) on the display unit 28. This notification screen includes a message that prompts the user to connect a GPS receiver or a GPS accessory to the digital camera 100. After that, the shooting control process returns to S301.

[0057] If it is determined in S303 that a GPS receiver is connected to the digital camera 100, the shooting control process proceeds to S305.

[0058] In S305, the system control unit 50 starts receiving time information and position information from the GPS receiver connected to the digital camera 100. The time information received from the GPS receiver is the time information contained in the GPS signal received by the GPS receiver from a GPS satellite. The position information received from the GPS receiver is the position information contained in the GPS signal received by the GPS receiver from a GPS satellite, and is information indicating the position of the GPS receiver. In other words, the position information received from the GPS receiver is essentially information indicating the position of the digital camera 100 connected to the GPS receiver.

[0059] Next, in S306, the system control unit 50 determines whether or not the reception of the time information and the position information from the GPS receiver has been successful. If it is determined that the reception of the time information and the position information from the GPS receiver has been successful, the shooting control process proceeds to S307.

[0060] In S307, the system control unit 50 displays the success screen of Fig. 4(c) on the display unit 28. This success screen includes a message indicating that the function of acquiring time information and location information from the GPS receiver has been enabled. After that, the shooting control process proceeds to S314, which will be described later.

[0061] If it is determined in S306 that reception of the time information and the position information from the GPS receiver has failed, the photographing control process proceeds to S308. Note that, as an example of a case where reception of the time information and the position information from the GPS receiver has failed, the GPS function of the GPS receiver may be disabled.

[0062] In S308, the system control unit 50 displays the failure screen of Fig. 4(d) on the display unit 28. This failure screen includes a message indicating measures to be taken to successfully receive the time information and position information, for example, a message prompting the user to check whether the GPS function is enabled in the GPS receiving device. After that, the shooting control process returns to S301.

[0063] In S302, if the digital camera 100 is equipped with the GPS receiving unit 119, or if a GPS accessory is connected to the digital camera 100 that does not have the GPS receiving unit 119, it is determined that the digital camera 100 has a GPS receiving function. In this case, the shooting control process proceeds to S309.

[0064] In S309, the system control unit 50 determines whether or not a GPS signal is being received. If it is determined that a GPS signal is not being received, the system control unit 50 enables the GPS function in the digital camera 100. After that, the shooting control process proceeds to S310.

[0065] In S310, the system control unit 50 controls the GPS receiving unit 119 or the GPS accessory to start receiving GPS signals from GPS satellites. Next, in S311, the system control unit 50 determines whether or not the reception of the GPS signal has been successful. If it is determined that the reception of the GPS signal has failed, the shooting control process proceeds to S312. Note that an example of a failure to receive the GPS signal is when the user who owns the digital camera 100 is indoors or underground and cannot properly receive the signal from the GPS satellite.

[0066] In S312, the system control unit 50 displays the reception failure notification screen of FIG. 4(e) on the display unit 28. This reception failure notification screen includes a message indicating that reception of the GPS signal has failed and a message indicating measures to be taken to successfully receive the GPS signal. After that, the shooting control process returns to S301. Thus, in this embodiment, if the digital camera 100 fails to receive a GPS signal from a GPS satellite or fails to receive time information and position information from a GPS receiver (NO in S306), the authenticity assurance mode is kept disabled. This makes it possible to prevent the generation of an image file that includes a shooting date and time based on an inaccurate reference time that has not been adjusted using time information obtained from an external source.

[0067] On the other hand, if it is determined in S311 that the reception of the GPS signal has been successful, the shooting control process proceeds to S313. In S313, the system control unit 50 displays the reception success notification screen of Fig. 4(f) on the display unit 28. This notification screen includes, for example, a message indicating that the reception of the GPS signal has been enabled by setting the authenticity assurance mode to enabled.

[0068] Next, in S314, the system control unit 50 changes the interval at which position information is acquired from the outside (hereinafter, referred to as the "position information acquisition interval") to an interval shorter than the previously set interval. The position information acquisition interval is the interval at which the GPS receiver 119 or the GPS accessory receives a GPS signal including the position information of the digital camera 100 from a GPS satellite. Alternatively, the position information acquisition interval is the interval at which the digital camera 100 receives position information from a GPS receiver. As described above, the position information received from the GPS receiver is the position information of the GPS receiver included in the GPS signal received by the GPS receiver from a GPS satellite, and is essentially the position information of the digital camera 100 connected to the GPS receiver. In S314, for example, the position information acquisition interval is changed to 1 second, which is the shortest interval that can be set in the digital camera 100. This makes it possible to obtain more accurate position information of the digital camera 100.

[0069] Next, in S315, the system control unit 50 changes the time setting to automatic update. When the time setting is changed to automatic update, the reference time in the digital camera 100 is adjusted using time information acquired from outside. Note that the time information acquired from outside is, for example, time information included in a GPS signal received by the GPS receiver 119 or a GPS accessory. In addition, the time information acquired from outside is time information acquired from a GPS receiver connected to the digital camera 100 and is time information included in a GPS signal received by this GPS receiver from a GPS satellite.

[0070] Next, in S316, the system control unit 50 prohibits manual change of the reference time. This makes it possible to prevent a malicious user from changing the reference time of the digital camera 100 to a time different from the actual time, and from giving a different date and time as the shooting date and time to an image file obtained by shooting. After that, the shooting control process proceeds to S317. Also, if it is determined in S309 that a GPS signal is being received, the shooting control process proceeds to S317.

[0071] In S317, the system control unit 50 changes the setting value of the authenticity assurance mode to "ON" which indicates that the authenticity assurance mode is enabled. The changed setting value is stored in the memory 32. In the present embodiment, the setting value of the authenticity assurance mode is not changed to "ON" when the GPS receiving unit 119 fails to receive a GPS signal or fails to receive time information and location information from the GPS receiving device, but the present invention is not limited to this configuration. For example, in the above-mentioned case, when the setting value of the authenticity assurance mode is changed to "ON" and the user changes the reference time in the digital camera 100, the fact that the reference time has been changed by the user may be recorded in the shooting information 602 in FIG. 6 described later. This makes it possible to notify other users who view an image file generated by the digital camera 100 in a state in which the reference time in the digital camera 100 has been changed by the photographer that there is a concern that the image file was generated at a time different from the actual time.

[0072] Next, in S318, the system control unit 50 executes the shooting process in Fig. 5, which will be described later. Next, in S319, the system control unit 50 determines whether or not an instruction to change the authenticity assurance mode to invalid has been given. The system control unit 50 waits until an instruction to change the authenticity assurance mode to invalid has been given, and when an instruction to change the authenticity assurance mode to invalid has been given (YES in S319), the shooting control process proceeds to S320.

[0073] In S320, the system controller 50 changes the setting value of the authenticity assurance mode to “OFF”, which indicates that the authenticity assurance mode is disabled. The changed setting value is stored in the memory 32.

[0074] Next, in S321, the system control unit 50 determines whether or not a GPS signal has been received before the authenticity assurance mode was changed to "ON" in S317. If it is determined in S317 that a GPS signal has been received before the authenticity assurance mode was changed to "ON", the shooting control process ends. If it is determined in S317 that a GPS signal has not been received before the authenticity assurance mode was changed to "ON", the shooting control process proceeds to S322.

[0075] In S322, the system control unit 50 switches the GPS function to "disabled" and ends reception of the GPS signal. Note that in S322, control may be performed to return settings that were automatically changed when the GPS signal reception was successful, such as control to permit manual change of the reference time. After that, the shooting control process ends.

[0076] Fig. 5 is a flowchart showing the procedure of the photographing process of S318 in Fig. 3. The photographing process in Fig. 5 starts when a photographing start operation such as pressing the shutter button 61 is accepted, and ends when a photographing end operation such as ceasing to press the shutter button 61 is accepted.

[0077] 5, first, in S501, the system control unit 50 drives the shutter 101 arranged on the subject side of the imaging unit 22 to control the exposure time. Next, in S502, the system control unit 50 performs imaging processing to convert light from the subject received by the imaging unit 22 through the shutter 101 into an electrical signal (analog image data). Next, in S503, the system control unit 50 performs image processing such as development processing and encoding processing on the electrical signal obtained by the imaging processing in S502 to generate image data 604 in FIG.

[0078] Next, in S504, the system control unit 50 generates metadata 601 in Fig. 6. The metadata 601 is data constituting the image file 600 in Fig. 6 generated by the digital camera 100, and includes shooting information 602 and history information 603.

[0079] The shooting information 602 is information at the time of performing imaging processing to generate image data 604, and includes, for example, the shooting date and time, the photographer, the image size, the manufacturer and model of the digital camera 100, various shooting parameters set at the time of shooting, the shooting location, and a thumbnail image. The shooting information 602 is generated in accordance with a predetermined technical standard, for example, EXIF ​​(Exchangeable image file format). The shooting date and time included in the shooting information 602 is the shooting date and time based on a reference time that has been adjusted using the time information acquired from the outside. The shooting location included in the shooting information 602 is the location information included in a GPS signal received by the digital camera 100 from a GPS satellite or the location information acquired from a GPS receiver connected to the digital camera 100. The GPS receiver receives a GPS signal including the location information from a GPS satellite. If the shooting date and time is manually input, information indicating that the shooting date and time has been manually input may be recorded in the shooting information 602.

[0080] The history information 603 is information for proving the authenticity of the image data 604, and is used when verifying the source and history of the image data 604. The history information 603 is generated in accordance with a predetermined technical standard, for example, C2PA (Correspondence for Content Provenance and Authenticity), and has a prescribed structure. The history information 603 includes a history (Assertion) 613, a hash value 623 for guaranteeing the history 613, and a digital signature 633. The history 613 includes history identification information (Manifest ID) for uniquely identifying the history, editing history information indicating the editing content of the image data 604, editing tool information indicating the tool used for the editing, creator information of the image data 604, and the like. Here, the image data 604 generated in step S503 has just been generated by shooting and has not been edited, so information indicating "generation" is recorded in the editing history, and information indicating the digital camera 100 is recorded in the editing tool. Furthermore, by including thumbnail data and metadata at the time of shooting and editing in the history 613, it is possible to use them for comparison and verification of changes.

[0081] 5, in S505, the system control unit 50 generates a hash value 623. Specifically, the system control unit 50 executes a hash function on the binary data of the image data 604 and the history 613, respectively, to generate a hash value 624 of the image data and a hash value 626 of the history. The system control unit 50 may execute a hash function on the binary data of the shooting information 602 to generate a hash value 625 of the shooting information. Also, for the history 613, hash values ​​may be generated for each finer unit, such as an editing history, a production source, thumbnail data, or metadata, so that tampering can be detected in finer units.

[0082] Next, in S506, the system control unit 50 generates a digital signature 633. The digital signature 633 includes information indicating a signature value, a signer, and a signature date and time. The signature value is generated by encrypting the hash value 623 generated in S505 using a private key prepared in advance. The public key that pairs with the private key used here is also included in the digital signature 633. Note that, in order to prove that the public key is from a trustworthy manufacturer, the digital signature 633 may include information indicating the manufacturer of the digital camera 100 as a signer, or a public key certificate indicating that the public key has been authenticated by a certification authority. By adding the digital signature 633 including such a signer to the image file 600, it is possible to show that the image file is trustworthy. Note that, instead of the manufacturer, the model of the digital camera 100 may be used as the signer. The signature date and time is the date and time when the generation of the digital signature 633 is completed. The shooting date and time may also be included in the history 613.

[0083] Next, in S507, the system control unit 50 assigns the shooting information 602 and the history information 603 to the image data 604 as metadata 601, and generates an image file 600. Here, if the image data 604 is a still image, the image file 600 is generated in accordance with the JPEG format, and if the image data 604 is a moving image, the image file 600 is generated in accordance with the MPEG format. After that, the shooting process ends.

[0084] As described above, in this embodiment, when the digital camera 100 captures an image in the authenticity guaranteed mode, the image file 600 is generated. The image file 600 may be edited. When the image file 600 is edited using an approved editing tool in a legitimate procedure, the history information 603 is newly generated in accordance with a predetermined technical standard based on the edited content and added to the metadata 601 of the image file 600. The history information 603 is newly generated every time the image file 600 is edited and added to the metadata 601 of the image file 600. On the other hand, when the image file 600 is edited using an unauthorized editing tool or in an illegal procedure, the history information 603 may not be assigned to the image file 600, or the history information 603 assigned to the image file 600 may not conform to the predetermined technical standard.

[0085] Also, by generating a hash value or a signature value, it is possible to detect tampering of the image file 600. For example, a hash function is applied to the binary data of the image data 604 of the image file 600 to generate a hash value. Then, the generated hash value is compared with a hash value 624 of the image data of the image file to be judged. This makes it possible to verify whether the image data has been tampered with or not. Similarly, a hash function is applied to the binary data of the shooting information 602 of the image file 600 to generate a hash value. Then, the generated hash value is compared with a hash value 625 of the shooting information of the image file to be judged. This makes it possible to verify whether the shooting information, which includes the shooting date and time, the shooting location, etc., has been tampered with or not. Furthermore, a hash function is applied to the binary data of the history 613 to generate a hash value. Then, the generated hash value is compared with a hash value 626 of the history of the image file to be judged. This makes it possible to verify whether the history information 603 has been tampered with or not. At this time, the binary data to be compared may be compared in smaller units such as an editing history, a production source, thumbnail data, or metadata. In addition, the signature value can be decrypted using a public key, and if the hash values ​​match, it can be determined that the signature value has been successfully verified. In this way, a mechanism for detecting tampering can be built into image files.

[0086] According to the embodiment described above, when an instruction to change the authenticity assurance mode from disabled to enabled and an instruction to generate an image file are received, an image file 600 is generated that includes a shooting date and time based on a reference time that has been adjusted using time information received from outside. This allows the image file 600 to include a shooting date and time based on an unfalsified reference time, thereby ensuring the authenticity of the generation time of the image file 600.

[0087] Furthermore, in the embodiment described above, in addition to the above-mentioned shooting date and time, the image file 600 includes the hash value 623 generated in S505 and the digital signature 633 generated in S506. This makes it possible to guarantee the authenticity of the image data included in the image file 600, in addition to the generation time of the image file 600.

[0088] In the above-described embodiment, the time information received from outside is the time information included in the GPS signal received from a GPS satellite by the GPS receiver 119. This makes it possible to set the reference time with high accuracy.

[0089] Furthermore, in the above-described embodiment, the time information received from outside is time information contained in a GPS signal received from a GPS satellite by a GPS accessory connected to digital camera 100 in a configuration in which digital camera 100 does not include GPS receiver 119. This allows digital camera 100 in a configuration in which digital camera 100 does not include GPS receiver 119 to set the reference time with high accuracy.

[0090] Furthermore, in the above-described embodiment, when an instruction to change the authenticity assurance mode from enabled to disabled is received, reception of GPS signals from GPS satellites by the GPS receiver 119 is stopped. This ensures the authenticity of the creation time of the image file 600 when the authenticity assurance mode is enabled, and reduces unnecessary power consumption when the authenticity assurance mode is disabled.

[0091] Furthermore, when the setting value of the authenticity assurance mode is "off" and the shooting process is executed after the process of step S322, the system control unit 50 executes the same processes as steps S501 to S503 in Fig. 5, and then adds the shooting information 602 to the image data 604 as metadata 601 to generate an image file 600. That is, the processes of steps S505 and S506 are not executed, and information related to guaranteeing the authenticity of the image data, such as the history information 603, hash value, digital signature, etc., is not added. Therefore, in the above-mentioned embodiment, when the authenticity of the shooting date and time cannot be guaranteed, it is possible not to guarantee the authenticity of the image data either.

[0092] Furthermore, in the above-described embodiment, the time information received from outside is time information received from a GPS receiver connected to digital camera 100, and this time information is time information included in a GPS signal received by this GPS receiver from a GPS satellite. This makes it possible for the image file 600 to include a shooting date and time based on an unfalsified reference time, even if digital camera 100 does not have a GPS reception function.

[0093] In the above embodiment, when an instruction to change the authenticity assurance mode from disabled to enabled is received, control is performed to prohibit a user from changing the reference time, thereby preventing a malicious user from falsifying the reference time.

[0094] Furthermore, in the above-described embodiment, when an instruction to change the authenticity assurance mode from disabled to enabled is received and reception of time information from an external source has failed, a notification of measures to be taken to successfully receive the time information from an external source is provided. This allows the photographer who takes pictures with the digital camera 100 to easily take measures to successfully receive the time information from an external source, which is necessary to guarantee the authenticity of the creation time of the image file 600.

[0095] In the above-described embodiment, the digital camera 100 is an imaging device that captures an image of a subject to generate image data and generates an image file containing the image data as content. This makes it possible to guarantee the authenticity of the generation time of the image file 600 in such an imaging device.

[0096] In this embodiment, when the digital camera 100 operates in the authenticity assurance mode, the GPS function is set to "enabled" and the GPS signal is received to set and update the accurate time, but other methods may be used. For example, when the digital camera 100 operates in the authenticity assurance mode, the Wi-Fi communication function may be set to "enabled", the digital camera 100 may connect to a Wi-Fi router to receive time information, and the reference time in the digital camera 100 may be adjusted based on the received time information. This makes it possible to ensure the authenticity of the content generation time in a device that does not have a GPS function but has a Wi-Fi communication function. The Wi-Fi router maintains the accurate time by periodically accessing an NTP (Network Time Protocol) server to adjust the time.

[0097] Furthermore, in a configuration in which digital camera 100 operates in an authenticity assurance mode and acquires time information from an external device such as a smartphone or PC connected to digital camera 100, this time information may be time information received by the external device from a Wi-Fi router. This makes it possible to guarantee the authenticity of the content generation time in a configuration in which communication is performed with an external device that does not have a GPS function but does have a Wi-Fi communication function.

[0098] Also, when the digital camera 100 operates in the authenticity assurance mode, the radio clock time adjustment function can be set to "enabled" and the reference time can be adjusted based on the date and time information (time code) contained in the radio waves received from the standard radio wave transmitting station. This makes it possible to guarantee the authenticity of the content generation time even if the digital camera does not have a GPS function.

[0099] Furthermore, when the digital camera 100 operates in the authenticity guarantee mode, the "automatic date and time setting" can be set to "enabled" to automatically obtain time information from a GPS signal, a Wi-Fi router, a standard radio wave transmitter (NITZ), etc., as described above, and set the reference time. This allows the digital camera 100 to guarantee the authenticity of the content generation time.

[0100] Furthermore, when the digital camera 100 changes "automatic date and time setting" from "enabled" to "disabled" in response to a user operation, the authenticity assurance mode may also be automatically changed from "enabled" to "disabled." Before changing "automatic date and time setting" from "enabled" to "disabled," a message may be displayed on the screen to notify the user that the authenticity assurance mode will also be changed from "enabled" to "disabled."

[0101] In this embodiment, a configuration for generating an image file has been described as an example of content, but the present invention is not limited to image files and can also be applied to, for example, a configuration for generating an audio file composed of audio data.

[0102] In the present embodiment, a digital camera has been described as an example of the content generating device of the present invention, but the content generating device is not limited to a digital camera. The content generating device may be any device that generates content and allows a user to change the reference time in the content generating device used to determine the generation time of the content, such as a smartphone, a tablet terminal, or a PC.

[0103] (Other embodiments) The present invention can also be realized by executing the following process. That is, software (program) that realizes the functions of the above-mentioned embodiments is supplied to a system or device via a network or various storage media, and the computer (or CPU, MPU, etc.) of the system or device reads and executes the program code. In this case, the program and the storage medium storing the program constitute the present invention. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0104] The disclosure of this embodiment includes the following configurations and methods. (Configuration 1) A content generation device comprising: a means for receiving an instruction to generate content from a user; a means for receiving an instruction from the user to change an authenticity assurance mode for guaranteeing authenticity of the content to enabled or disabled; and a control means for controlling the generation of the content, wherein when an instruction to change the authenticity assurance mode from disabled to enabled and an instruction to generate the content are received, the control means generates the content including a generation time of the content based on a reference time that has been adjusted using time information received from an external source. (Configuration 2) The content generation device according to configuration 1, characterized in that when an instruction to change the authenticity assurance mode from disabled to enabled and an instruction to generate the content are received, the control means generates the content including the generation time, a hash value generated by applying a hash function to the content, and a digital signature generated by encrypting the hash value using a private key. (Configuration 3) A content generating device as described in configuration 1 or 2, further comprising a receiving means for receiving a signal from an artificial satellite, wherein the time information received from the outside is time information contained in the signal received by the receiving means from the artificial satellite. (Configuration 4) The content generating device according to configuration 3, wherein when an instruction to change the authenticity assurance mode from enabled to disabled is received, the receiving means stops receiving the signal from the artificial satellite. (Configuration 5) The content generating device according to configuration 1 or 2, characterized in that the time information received from outside is time information contained in a signal received from an artificial satellite by an accessory connected to the content generating device for extending a GPS function. (Configuration 6) The content generation device described in configuration 1 or 2, characterized in that the time information received from the outside is time information received from an external device connected to the content generation device, the time information received from the external device is time information contained in a signal received by the external device from an artificial satellite, and the external device controls the process of receiving the signal from the artificial satellite by a control unit provided in the external device. (Configuration 7) The content generating device according to any one of configurations 1 to 6, wherein the reference time is changeable by a user. (Configuration 8) The content generating device according to configuration 7, wherein when an instruction to change the authenticity assurance mode from disabled to enabled is received, control is performed to prohibit a user from changing the reference time. (Configuration 9) The content generating device of any one of configurations 1 to 8, wherein the control means generates the content including location information acquired from an external source, and when an instruction is received to change the authenticity assurance mode from disabled to enabled, the interval at which the location information is acquired is changed to an interval shorter than a preset interval. (Configuration 10) A content generating device described in any one of configurations 1 to 9, characterized in that when an instruction to change the authenticity assurance mode from disabled to enabled is received and reception of time information from the outside is unsuccessful, the authenticity assurance mode remains disabled. (Configuration 11) A content generating device as described in any one of configurations 1 to 7, 9, and 10, characterized in that when an instruction to change the authenticity assurance mode from disabled to enabled is received, and reception of time information from the outside has failed, and a user has changed the reference time, the control means generates the content including information indicating that the reference time has been changed by the user. (Configuration 12) A content generating device described in any one of configurations 1 to 11, characterized in that when an instruction to change the authenticity assurance mode from disabled to enabled is received and reception of time information from the outside fails, measures to be taken to successfully receive time information from the outside are notified. (Configuration 13) The content generation device according to any one of configurations 1 to 12, characterized in that the content generation device is an imaging device that photographs a subject to generate image data and generates an image file containing the image data as the content. [Explanation of symbols]

[0105] 50 System control section 61 Shutter button 70 Operation section 100 Digital Camera 119 GPS receiver

Claims

1. A means for receiving an instruction to generate content from a user; a means for receiving an instruction from the user to change an authenticity assurance mode for assuring authenticity of the content to enabled or disabled; A control unit that controls the generation of the content, A content generation device characterized in that, when an instruction to change the authenticity assurance mode from disabled to enabled and an instruction to generate the content are received, the control means generates the content including a generation time of the content based on a reference time that has been adjusted using time information received from outside.

2. The content generation device according to claim 1, characterized in that, when an instruction to change the authenticity assurance mode from disabled to enabled and an instruction to generate the content are received, the control means generates the content including the generation time, a hash value generated by applying a hash function to the content, and a digital signature generated by encrypting the hash value using a private key.

3. Further comprising a receiving means for receiving a signal from an artificial satellite, 2. The content generating device according to claim 1, wherein the time information received from the outside is time information contained in a signal received by the receiving means from the artificial satellite.

4. 4. The content generating device according to claim 3, wherein, when an instruction to change the authenticity assurance mode from enabled to disabled is received, reception of the signal from the artificial satellite by the receiving means is stopped.

5. The content generation device according to claim 1, characterized in that the time information received from outside is time information contained in a signal received from an artificial satellite by an accessory connected to the content generation device for expanding GPS functions.

6. the externally received time information is time information received from an external device connected to the content generation device, the time information received from the external device is time information included in a signal received by the external device from an artificial satellite, The content generating device according to claim 1 , wherein the external device controls a process of receiving a signal from the artificial satellite by a control unit included in the external device.

7. 2. The content generating device according to claim 1, wherein the reference time is changeable by a user.

8. 8. The content generating device according to claim 7, wherein, when an instruction to change the authenticity assurance mode from disabled to enabled is received, control is performed to prohibit a user from changing the reference time.

9. The control means generates the content including location information acquired from an external source; The content generating device according to claim 1, characterized in that, when an instruction to change the authenticity assurance mode from disabled to enabled is received, the interval at which the location information is obtained is changed to an interval shorter than a preset interval.

10. 2. The content generating device according to claim 1, wherein, when an instruction to change the authenticity assurance mode from disabled to enabled is received and reception of time information from the outside has failed, the authenticity assurance mode is maintained as disabled.

11. The content generating device according to claim 1, characterized in that when an instruction to change the authenticity assurance mode from disabled to enabled is received, and reception of time information from the outside fails, and a user changes the reference time, the control means generates the content including information indicating that the reference time has been changed by the user.

12. The content generating device according to claim 1, characterized in that when an instruction to change the authenticity assurance mode from disabled to enabled is received and reception of time information from the outside fails, measures to be taken to successfully receive time information from the outside are notified.

13. 2. The content generation device according to claim 1, wherein the content generation device is an imaging device that captures an image of a subject to generate image data, and generates an image file including the image data as the content.

14. receiving an instruction to generate content from a user; receiving an instruction from the user to change an authenticity assurance mode for assuring authenticity of the content to enabled or disabled; a control step of controlling generation of the content, A control method for a content generating device, characterized in that, when an instruction to change the authenticity assurance mode from disabled to enabled and an instruction to generate the content are received, the control process generates the content including a generation time of the content based on a reference time that has been adjusted using time information received from outside.

15. A program for causing a computer to execute a method for controlling a content generating device, The method for controlling the content generating device includes: receiving an instruction to generate content from a user; receiving an instruction from the user to change an authenticity assurance mode for assuring authenticity of the content to enabled or disabled; a control step of controlling generation of the content, A program characterized in that, when an instruction to change the authenticity assurance mode from disabled to enabled and an instruction to generate the content are received, the control process generates the content including a generation time of the content based on a reference time that has been adjusted using time information received from an external source.

Images