Apparatus and method for signing a video segment comprising one or more groups of pictures

Abstract

Apparatus and method for signing video clips comprising one or more groups of pictures (GOPs). An apparatus (400), a non-transitory computer-readable storage medium (430), and a method (200) for signing video clips comprising one or more GOPs are disclosed, wherein each GOP includes a header and one or more frames. A GOP hash is generated (S210) for each GOP in the one or more GOPs, and the GOP hash is digitally signed (S220) to generate a signed GOP hash. For each GOP in the one or more GOPs except the last GOP, the corresponding signed GOP hash is stored (S230) in the header of the subsequent GOP. An additional GOP is appended (S240) to the video clip after the last GOP in the one or more GOPs, wherein the additional GOP includes a header and one or more frames. The signed GOP hash of the last GOP in the one or more GOPs is stored (S250) in the header of the additional GOP.

Description

Technical Field

[0001] This invention relates to the authentication of the content of video clips, and more particularly to signing video clips comprising one or more Groups of Pictures (GOPs). Background Technology

[0002] In some applications, it's desirable to verify that the content of a video clip is complete, meaning it hasn't been tampered with since its capture. Given the advancements in video technology that have made it possible to produce high-quality processed videos, achieving this verification has become even more crucial. One way to implement this verification for video clips comprising one or more Groups of Pictures (GOPs) is to create authentication information for each GOP in the video and include this information in the video clip. This authentication information can then be used at the decoder side to verify the completeness of the content of one or more GOPs. However, if the authentication information for a GOP is missing from the video clip, it's impossible to verify that the content of that GOP is complete, i.e., untampered with. Summary of the Invention

[0003] The purpose of this invention is to facilitate enhanced verification of the integrity of video segments comprising one or more Groups of Pictures (GOPs) (i.e., those that have not been tampered with after the video segments were captured).

[0004] According to the first aspect, a method for signing a video segment comprising one or more Groups of Pictures (GOPs) is provided. Each GOP includes a header and one or more frames. For each GOP in the one or more GOPs, a GOP hash is generated, and the GOP hash is digitally signed, thereby generating a signed GOP hash for each of the one or more GOPs. Furthermore, for each GOP in the one or more GOPs except the last GOP, the corresponding signed GOP hash is stored in the header of the subsequent GOP in the one or more GOPs. An appended GOP is added to the video segment after the last GOP in the one or more GOPs. The appended GOP includes a header and one or more frames. Then, the signed GOP hash of the last GOP in the one or more GOPs is stored in the header of the appended GOP.

[0005] By adding an appended GOP (Gate of Opposition) header to a video clip following the last GOP of one or more GOPs, and storing the signed GOP hash of the last GOP in the appended GOP header, it is guaranteed that the signed GOP hash of the last GOP of one or more GOPs is included in the video clip. Therefore, it can be guaranteed that the content of the last GOP in one or more GOPs has not been tampered with, but is actually identical to the hashed and signed content.

[0006] GOP hash refers to any value produced by hashing the contents of a GOP or by using any similar digestion method.

[0007] Digitally signing a GOP hash refers to any method used to verify the authenticity of the GOP hash, such as encrypting the GOP hash using the private key from a public / private key pair.

[0008] One or more frames included in an additional GOP can be pre-encoded.

[0009] By using one or more pre-encoded frames from an additional GOP, when adding an additional GOP to one or more GOPs of a video clip, no additional time and processing is required to encode one or more pre-encoded frames.

[0010] An additional GOP can include empty intra-frames and zero or more empty inter-frames. An empty intra-frame is a blank frame, and an empty inter-frame is a frame that relates to another frame and does not include updates associated with the frame it relates to. By including empty intra-frames and optionally one or more empty inter-frames, the number of additional bits added to the video frame when adding an additional GOP is reduced compared to adding non-empty frames.

[0011] The additional GOP can further include information indicating that it is the last GOP of the video segment. Including this information makes it possible to identify the additional GOP at the decoder side. This is advantageous because it can then be determined at the decoder side that the preceding GOP is the last GOP containing verifiable content, and adding the additional GOP with this indication is solely for the purpose of verifying the content of the preceding GOP.

[0012] A GOP hash can be generated by generating a frame hash for each frame in one or more frames of a GOP, thereby generating one or more frame hashes, and then performing a hash operation on the one or more frame hashes to generate the GOP hash.

[0013] The GOP hash is generated by hashing one or more frame hashes, and only one hash needs to be checked to determine whether the GOP has been tampered with.

[0014] Generating a GOP hash may further include hashing one or more frame hashes using metadata, which includes at least one of the following: a unique identifier of the camera that captured the video segment and a timestamp of the video segment. The metadata may further include at least one of the following: hardware type (camera type), firmware version, GPS location, frame tag, and bootstrap count.

[0015] By generating a GOP hash by also hashing the metadata with one or more frame hashes, it is possible to determine whether the metadata has been tampered with.

[0016] One or more frame hashes can be further concatenated with a GOP hash generated by hashing one or more frame hashes to produce a concatenated GOP hash. Digitally signing the GOP hash can further include signing the concatenated GOP hash using a digital signature method to produce a signed GOP hash.

[0017] If it is determined that a GOP has been tampered with using GOP hashing, then one or more frame hashes of the signed GOP hash can then be used to identify which frame(s) have been tampered with.

[0018] According to the second aspect, a non-transitory computer-readable storage medium is provided having instructions stored thereon, which, when executed on a processing device, are used to implement the method according to the first aspect.

[0019] Where applicable, the aforementioned optional additional features of the method according to the first aspect also apply to the second aspect. To avoid unnecessary repetition, please refer to the above.

[0020] According to a third aspect, an apparatus is provided for signing a video segment comprising one or more Group of Pictures (GOPs). Each GOP includes a header and one or more frames. The apparatus includes circuitry configured to perform: a GOP hash generation function configured to generate a GOP hash for each GOP in the one or more GOPs; a GOP hash signing function configured to digitally sign the GOP hash of each GOP in the one or more GOPs, thereby generating a corresponding signed GOP hash for each GOP in the one or more GOPs; a GOP addition function configured to add an additional GOP to a video segment following the last GOP in the one or more GOPs, the additional GOP including a header and one or more frames; and a signed GOP hash storage function configured to store the corresponding signed GOP hash in the header of the subsequent GOP for each GOP in the one or more GOPs, wherein the signed GOP hash of the last GOP in the one or more GOPs is stored in the header of the additional GOP.

[0021] Where applicable, the aforementioned optional additional features of the method according to the first aspect also apply to the third aspect. To avoid unnecessary repetition, please refer to the above.

[0022] Further applications of the invention will become apparent from the detailed description given below. However, it should be understood that while the detailed description and specific examples indicate preferred embodiments of the invention, they are given by way of illustration only, as various variations and modifications within the scope of the invention will become apparent to those skilled in the art from this detailed description.

[0023] Therefore, it should be understood that the present invention is not limited to the specific components of the described apparatus or the operation of the described method, as such apparatus and method can vary. It should also be understood that the terminology used herein is merely for describing particular embodiments and is not intended to be limiting. It must be noted that, as used in the specification and appended claims, the articles “a,” “an,” “the,” and “the” are intended to indicate the presence of one or more elements unless the context clearly indicates otherwise. Thus, for example, a reference to “a unit” or “the unit” can include several devices, etc. Furthermore, the words “comprising,” “including,” and similar wording do not exclude other elements or steps. Attached Figure Description

[0024] The above and other aspects of the invention will now be described in more detail with reference to the accompanying drawings. The drawings should not be considered limiting, but rather for explanation and understanding.

[0025] Figure 1 An illustration shows an example of a video clip that includes multiple Groups of Pictures (GOPs).

[0026] Figure 2 A flowchart is shown in connection with an embodiment of the method disclosed herein for signing video segments comprising one or more GOPs.

[0027] Figure 3a An illustration shows the signing of a GOP that is not the last GOP of a video segment, according to an embodiment of the method of this disclosure.

[0028] Figure 3b An illustration shows the signing of the last GOP of a video segment according to an embodiment of the method disclosed herein.

[0029] Figure 4 A schematic diagram is shown in relation to an embodiment of the apparatus disclosed herein for signing video segments comprising one or more GOPs. Detailed Implementation

[0030] The invention will now be described below with reference to the accompanying drawings, which illustrate presently preferred embodiments of the invention. However, the invention may be embodied in various different forms and should not be construed as limited to the embodiments set forth herein.

[0031] In applications where a digitally signed GOP hash is created for each GOP in a video sequence and the digitally signed GOP hash of each GOP is included in subsequent GOPs of the video segment, embodiments of the present invention can be used to ensure the integrity of the video segment content, i.e., that it has not been tampered with after the video was captured. At the decoder side, the digital signature of the GOP can be used to verify the origin of the GOP. For example, if the digital signature of the GOP is created by encrypting the GOP hash using the private key in a public / private key pair, the signature origin can be verified by decrypting it using the public key in the public / private key pair. Furthermore, the GOP hash can be generated from the content of the GOP received at the decoder side and compared with the (decrypted) digitally signed GOP hash. If they are equal, the content of the GOP is complete; if they are not equal, the content of the GOP is incomplete. Additionally, for this application, the digitally signed hash of the last GOP in the video sequence will not be included in the video sequence because there are no subsequent GOPs for the last GOP in the video segment. Therefore, it cannot be guaranteed that the content of the last GOP is complete, i.e., not tampered with after capture. Furthermore, if the last GOP only includes a few frames before the end of the video segment, the number of frames is too small to verify its completeness. However, the time spent generating the digitally signed GOP hash for the penultimate GOP might prevent it from being included in the first few frames of the last GOP before the end of the video segment. Therefore, in this case, the signed GOP hash of the penultimate GOP will not be included in the video segment, and its content cannot be verified as complete. In this case, it is guaranteed that the signed GOP hash of the penultimate GOP will be included in the last GOP. Alternatively, GOP hashes can be generated for both the penultimate and last GOPs and included in the additional GOP.

[0032] Embodiments of the present invention are advantageous when there is a risk that a large number of frames of a video segment are located in the last GOP of the video segment. For example, if the end of a video segment is determined without considering the end of the last GOP, the probability that the end of the video segment is after a given frame will be consistent across all frames in the last GOP. Therefore, the more frames in each GOP, the higher the probability that a large number of frames of the video segment are located in the last GOP of that video segment. An example in which the end of a video segment is determined without considering the end of the last GOP is when the video segment involves surveillance video, and where the video segment begins when a trigger starts activity and ends when the trigger stops activity. In this example, the video segment will end after a random position relative to the end of the current GOP. Therefore, as the number of frames included in each GOP increases, the risk that a large portion of the video segment is located in the last GOP increases. Furthermore, since the start and end of the video segment are related to the start and stop of trigger activity, the last GOP of the video segment may also include information of interest. The trigger could be motion detection, human / face detection, door opening detection, etc. For example, if the trigger is a movement or person / face in video captured by a surveillance camera, the trigger can start moving when a person appears to be moving towards the camera and stop moving when the person passes the camera. In this case, the face will be closest to the camera and the trigger will stop moving just before the person passes the camera (i.e., at the end of the video segment). Therefore, the frame where the face is closest to the camera and is likely the easiest to identify is probably located in the penultimate or last GOP of the video segment.

[0033] Embodiments of the present invention are more advantageous when a video segment comprises only one GOP. In this case, that single GOP will also be the last GOP, resulting in all frames of the video segment being located in the last GOP of the video segment, and any frame containing information of interest will also be located in the last GOP.

[0034] Figure 1An illustration shows an example of a video segment 100 comprising multiple Groups of Pictures (GOPs) 101-104 that can be used in conjunction with embodiments of the present invention. Each GOP comprises multiple frames, wherein the first frame is an intra-frame I, followed by six inter-frame frames P1-P6 in the first three GOPs 101-103, and four inter-frame frames P1-P4 in the last GOP 104 of the video segment. The video segment 100 may, for example, be a video segment 100 whose end has been determined without considering the end of the last GOP. The first three GOPs 101-103 of the video segment are complete GOPs, while the last GOP 104 may only include a subset of the frames of the complete GOP. For example, the last GOP 104 of the video segment 100 includes one intra-frame I and four inter-frame frames P1-P4. If the video segment does not end after the fourth inter-frame frame P4, the GOP may have already included further inter-frame frames. Video segment 100 may, for example, involve video frames captured by a camera such as a surveillance camera, wearable camera, etc., and subsequently encoded by an encoder.

[0035] It should be noted that, Figure 1 The video segment 100 is a simplified illustration. For example, the number of inter-frames per GOP can be more than illustrated, such as several hundred inter-frames, and can vary between GOPs. Furthermore, the number of GOPs in a video segment can be more or less than the four GOPs 101-104 illustrated, depending on the length of the video segment and the length of each of the included GOPs. Moreover, although the disclosed examples primarily relate to P-frames, the invention is also applicable to and can be extended to other types of inter-coded frames, such as B-frames, which may involve more than one other frame.

[0036] Now refer to Figure 1 , Figure 2 , Figure 3a and Figure 3b An embodiment of a method 200 for signing a video segment comprising n Groups of Pictures (GOPs) is described, wherein n ≥ 1 (i.e., one or more GOPs), and wherein each GOP includes a header and one or more frames. Method 200 includes generating a GOP hash (S210) and digitally signing the GOP hash (S220) to sign the video segment (such as...). Figure 1 Each GOP (i.e., each of the n GOPs) in the video clips generates a signed GOP hash (S208, S222, C224).

[0037] Go to Figure 3aThe GOP hash of GOP i can be based on the frame hashes of frames I and P1-P6 of GOP i. The frame hash of a frame is generated by applying a hash function H to the content of the frame. Examples of mathematical hash functions are identity hash, folding, division hash, multiplication hash, Fibonacci hash, and Zobrist hash. Examples of cryptographic hash functions are MD5, SHA-1, SHA-2 (SHA-256 / SHA-512), SHA-3, and BLAKE-3. For example, the frame hashes of each of frames I and P1-P6 can be concatenated (310) and then hashed using hash function H to generate the GOP hash for GOP i. Alternatively, metadata MD can also be concatenated (310) with the frame hashes of each of frames I and P1-P6 to generate the GOP hash for GOP i. The metadata MD can include at least one of the following: a unique identifier for the video segment captured by the camera, a timestamp of the video segment, hardware type (camera type), firmware version, GPS location, frame tag, and bootstrap count. Then, the GOP hash is signed using any type of digital signature capable of verifying the source of the GOP, for example, by encrypting the GOP hash using the private key from the public / private key pair of the device (such as a camera) in which the method is performed. For example, RSA (Rivest-Shamir-Adleman) 256-bit encryption, Digital Signature Algorithm (DSA), and Elliptic Curve Digital Signature Algorithm (ECDSA) can be used to digitally sign the GOP hash.

[0038] A GOP hash is generated for GOP i by concatenating the hashes of one or more frames (P1-P6) of GOP i, with or without metadata MD, and then digitally signing the GOP hash 320. This allows verification at the GOP level that the content of GOP i is complete, i.e., tamper-proof. Alternatively, one or more frame hashes of GOP i can be concatenated with the GOP hash of GOP i. Figure 3a (Not shown in the diagram), a concatenated GOP hash is generated for GOP i, and then digitally signed 320 using a digital signature method to generate a signed GOP hash. In this alternative, a portion of the signed GOP hash associated with the GOP hash can be used to verify at the GOP level that the content of the GOP is complete, i.e., not tampered with. If it indicates that the GOP is incomplete, a portion of the signed GOP hash associated with one or more concatenated frame hashes can be used to identify which of the one or more frame hashes has been tampered with by comparing it with a frame hash generated from the content of the GOP's frames at the decoder side.

[0039] Furthermore, a frame hash can be generated for the first frame I of the subsequent GOP i+1 and added to the GOP hash of GOP i before signing, so that GOP reordering and undetectable cuts can be identified. Alternatively, the GOP hash of GOP i can be generated by hashing a concatenation of the frame hash of GOP i's frame and the frame hash of the first frame I of the subsequent GOP i+1.

[0040] Back Figure 2 If the number of GOPs n is greater than 1 (C226) (i.e., the first GOP is not the only GOP, and therefore not the last GOP), the method further includes, for each GOP i = 1 to n-1 (S228, S232, C234), that is, for each GOP except the last GOP, storing the signed GOP hash of GOP i in the header of the subsequent GOP i+1 in S230.

[0041] Go to Figure 3a The signed GOP hash of GOP i is included in the header of subsequent GOP i+1. For example, the GOP hash can be included in the header of GOP i+1. Figure 3a The different metadata frames (not shown) of GOP i in frames I, P1-P6.

[0042] Back Figure 2 The method further includes adding an appended GOP n+1 to the video segment following the last GOP n in the n GOPs, S240, wherein the appended GOP n+1 includes a header and one or more frames. Then, the signed GOP hash of the last GOP n in the n GOPs is stored in the header of the appended GOP n+1, S250.

[0043] The appended GOP n+1 can be of any type, as long as it includes the GOP hash of the last GOP n. However, it is beneficial to keep the GOP size as small as possible to avoid unnecessarily increasing the size of the video clip and to generate the appended GOP n+1 in a way that requires less processing and keeps processing time low.

[0044] For example, one or more frames included in an appended GOP can be pre-encoded. This means that the content of one or more frames has already been pre-encoded. By using one or more pre-encoded frames, no additional time or resources are needed to encode the content when adding an appended GOP. It is possible to use one or more pre-encoded frames in an appended GOP because the appended frames are primarily used to carry the signed hash of the last GOP n out of n GOPs. Therefore, the content of the appended frames does not need to be related to the content of other GOPs in the video frame. Furthermore, since there are no other GOPs after appended GOP n+1, it is impossible to include the signed GOP hash of the appended GOP in any subsequent GOP, and therefore the content of the appended GOP cannot be verified as tamper-proof.

[0045] Furthermore, one or more frames that are appended to a GOP can be empty intra-frames, and optionally one or more empty inter-frames. An empty intra-frame is a blank frame that only has intra-prediction and does not contain coding coefficients, and an empty inter-frame is a frame that relates to another frame and does not contain updates associated with the frame it relates to. By including empty intra-frames and optionally one or more empty inter-frames, the number of additional bits added to the video frame when appending a GOP is reduced compared to adding non-empty frames.

[0046] The additional GOP may further include information indicating that it is the last GOP of the video segment. This information may be included, for example, as additional metadata in the header of the additional GOP, which can be interpreted at the decoder to indicate that the additional GOP is the last GOP of the video segment. The additional metadata may further be used to indicate that the additional GOP is only used to verify the completeness of the previous GOP. Additionally or alternatively, the information indicating that the additional GOP is the last GOP of the video segment may be included in the content of the additional GOP. For example, the additional GOP may be a pre-encoded frame that includes content indicating that the GOP is the last GOP of the video segment after encoding and display, such as displaying text indicating that the GOP is the last GOP of the video segment. In alternatives to including additional metadata in the header, the additional metadata may be encoded into the video data of the additional GOP as a weak (virtually invisible) "watermark," added to out-of-frame encoded data (i.e., data indicating the end of a frame and the start of the next frame), or added to an undefined Network Abstraction Layer (NAL).

[0047] Go to Figure 3bThe GOP hash of GOP n can be based on the frame hashes of frames I and P1-P4 of GOP i. For example, generating the GOP hash for GOP n can include using a hash function H to generate frame hashes for each frame I and P1-P4 of GOP n. Then, the frame hashes of each of frames I and P1-P4 can be concatenated 310 times, and then hashed using the hash function H to generate the GOP hash for GOP n. Alternatively, metadata MD can also be concatenated 310 times with the frame hashes of each of frames I and P1-P4 to generate the GOP hash for GOP n. The metadata MD can include at least one of the following: a unique identifier of the video segment captured by the camera, a timestamp of the video segment, hardware type (camera type), firmware version, GPS location, frame tag, and boot count. The GOP hash is then signed 320 using any type of digital signature capable of verifying the origin of the GOP, for example, by encrypting the GOP hash using the private key in the public / private key pair of the device (such as a camera) in which the method is performed. For example, RSA (Rivest-Shamir-Adleman) 256-bit encryption, Digital Signature Algorithm (DSA), and Elliptic Curve Digital Signature Algorithm (ECDSA) can be used to digitally sign GOP hashes.

[0048] A GOP hash is generated for GOP n by concatenating the hashes of one or more frames (P1-P4) of GOP n, with or without metadata MD, and then digitally signing the GOP hash 320. This allows verification at the GOP level that the content of GOP n is complete, i.e., tamper-proof. Alternatively, one or more frame hashes of GOP n (frames I, P1-P4) can be concatenated with the GOP hash of GOP n. Figure 3b (Not shown in the diagram), a concatenated GOP hash is generated for GOP n, and then digitally signed 320 using a digital signature method to generate a signed GOP hash. In this alternative, a portion of the signed GOP hash associated with the GOP hash can be used to verify at the GOP level that the content of the GOP is complete, i.e., not tampered with. If the GOP is shown to be incomplete, a portion of the signed GOP hash associated with one or more concatenated frame hashes can be used to identify which frame in one or more frame hashes has been tampered with by comparing it with a frame hash generated from the frame content of the GOP at the decoder side.

[0049] Furthermore, a frame hash can be generated for the first frame I of the subsequent GOP i+1 and added to the GOP hash of GOP i before signing, so that GOP reordering and undetectable cuts can be identified. Alternatively, the GOP hash of GOP i can be generated by hashing a concatenation of the frame hash of GOP i's frame and the frame hash of the first frame I of the subsequent GOP i+1.

[0050] Figure 4 A schematic diagram is shown in relation to an embodiment of the apparatus 400 disclosed herein for signing video clips comprising one or more Group of Pictures (GOPs), each GOP including a header and one or more frames. The apparatus 400 may be a camera such as a surveillance camera or a wearable camera. The apparatus 400 includes circuitry 410. Circuitry 410 is configured to perform functions 432, 434, 436, and 438 of the apparatus 400. Circuitry 410 may include a processor 412, such as a central processing unit (CPU), microcontroller, or microprocessor. Processor 412 is configured to execute program code. The program code may, for example, be configured to perform functions 432, 434, 436, and 438 of the apparatus 400.

[0051] Device 400 may further include memory 430. Memory 430 may be one or more of a buffer, flash memory, hard disk drive, removable media, volatile memory, non-volatile memory, random access memory (RAM), or other suitable devices. In a typical arrangement, memory 430 may include non-volatile memory for long-term data storage and volatile memory serving as system memory for circuit 410. Memory 430 may exchange data with circuit 410 via a data bus. Accompanying control lines and address buses may also exist between memory 430 and circuit 410.

[0052] Functions 432, 434, 436, and 438 of device 400 can be implemented as executable logic routines (e.g., lines of code, software programs, etc.) stored on a non-transitory computer-readable medium (memory) 430 of device 400 and executed by circuit 410 (e.g., using processor 412 in circuit 410). Furthermore, functions 432, 434, 436, and 438 of device 400 can be standalone software applications or form part of a software application. The described functions can be considered as methods configured to execute by processing units such as processor 412 of circuit 410. Moreover, while the described functions 432, 434, 436, and 438 can be implemented in software, they can also be implemented by dedicated hardware or firmware, or a combination of hardware, firmware, and / or software.

[0053] Circuit 410 is configured to perform a GOP hash generation function, which is configured to generate a GOP hash for each GOP in one or more GOPs.

[0054] Circuit 410 is further configured to perform a GOP hash signing function, which is configured to digitally sign the GOP hash of each GOP in one or more GOPs, thereby generating a corresponding signed GOP hash for each GOP in one or more GOPs.

[0055] Circuit 410 is further configured to perform a GOP addition function, which is configured to add an additional GOP to a video segment after the last GOP in one or more GOPs, the additional GOP including a header and one or more frames.

[0056] Circuit 410 is further configured to perform a signed GOP hash saving function, which is configured to save the corresponding signed GOP hash in the header of the subsequent GOP for each of one or more GOPs, wherein the signed GOP hash of the last GOP in one or more GOPs is saved in the header of the additional GOP.

[0057] The device 400 and the functions 432, 434, 436, 438 performed by the circuit 410 can be further adapted to the method 200 and respectively combined with Figure 1 , Figure 2 , Figure 3a and Figure 3b The corresponding steps of the described method 200.

[0058] The apparatus 400 may further include an encoder (not shown) for encoding frames of a video segment that include one or more frames of an appended GOP.

[0059] Those skilled in the art will recognize that the present invention is not limited to the embodiments described above. Rather, various modifications and variations are possible within the scope of the appended claims. Such modifications and variations can be understood and implemented by those skilled in the art in practicing the claimed invention by studying the drawings, the disclosure, and the appended claims.

Claims

1. A method for signing a video segment comprising one or more Group of Pictures (GOPs), each GOP comprising a header and one or more encoded frames, the method comprising: For each of the one or more GOPs: Generate GOP hash; as well as The GOP hash is digitally signed using a digital signature method to generate a signed GOP hash; For each of the one or more GOPs except the last GOP: The corresponding signed GOP hash is stored in the header of subsequent GOPs; The video segment after the last GOP in the one or more GOPs is added with an additional GOP, the additional GOP including a header and one or more encoded frames; as well as The signed GOP hash of the last GOP in the one or more GOPs is stored in the header of the additional GOP.

2. The method according to claim 1, wherein, The additional GOP includes empty intra-frames and zero or more empty inter-frames.

3. The method according to claim 1, wherein, The additional GOP includes information indicating that the additional GOP is the last GOP of the video segment.

4. The method according to claim 1, wherein, Generating a GOP hash includes: Generate a frame hash for each of the one or more encoded frames of the GOP, thereby generating one or more frame hashes; and The hash operation is performed on the one or more frame hashes to generate the GOP hash.

5. The method according to claim 4, wherein, Generating the GOP hash further includes: performing a hash operation on the one or more frame hashes using metadata to generate the GOP hash, wherein the metadata includes at least one of a unique identifier of the camera that captured the video segment and a timestamp of the video segment.

6. The method of claim 4, further comprising: The one or more frame hashes are concatenated with the GOP hash to generate a concatenated GOP hash, and the digital signature of the GOP hash further includes: signing the concatenated GOP hash using a digital signature method to generate a signed GOP hash.

7. A non-transitory computer-readable storage medium having instructions stored thereon, which, when executed on a processing device, are used to implement the method according to any one of claims 1 to 6.

8. An apparatus for signing a video segment comprising one or more Group of Pictures (GOPs), each GOP including a header and one or more encoded frames, the apparatus including circuitry configured to perform: The GOP hash generation function is configured to generate a GOP hash for each of the one or more GOPs. as well as The GOP hash signing function is configured to digitally sign the GOP hash of each of the one or more GOPs, thereby generating a corresponding signed GOP hash for each of the one or more GOPs. The GOP addition feature is configured to add an additional GOP to the video segment after the last GOP in one or more GOPs, the additional GOP comprising a header and one or more encoded frames; as well as The signed GOP hash saving function is configured to save the corresponding signed GOP hash in the header of the subsequent GOP for each of the one or more GOPs, wherein the signed GOP hash of the last GOP of the one or more GOPs is saved in the header of the additional GOP.

9. The apparatus according to claim 8, wherein, The additional GOP includes empty intra-frames and zero or more empty inter-frames.

10. The apparatus according to claim 8, wherein, The additional GOP includes information indicating that the additional GOP is the last GOP of the video segment.

11. The apparatus according to claim 8, wherein, The GOP hash generation function is configured to generate GOP hashes in the following manner: Frame hashes are generated for each of the one or more encoded frames in the GOP, thereby generating one or more frame hashes; as well as The hash operation is performed on the one or more frame hashes to generate the GOP hash.

12. The apparatus according to claim 11, wherein, Generating the GOP hash further includes: performing a hash operation on the one or more frame hashes using metadata to generate the GOP hash, wherein the metadata includes at least one of a unique identifier of the camera that captured the video segment and a timestamp of the video segment.

13. The apparatus of claim 11, further comprising: The one or more frame hashes are concatenated with the GOP hash to generate a concatenated GOP hash, and the digital signature of the GOP hash further includes: signing the concatenated GOP hash using a digital signature method to generate a signed GOP hash.

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