Method and system for processing digital content, method and system for verifying copyright of digital content, and method and system for tracking digital content

Abstract

A method for processing digital content includes acquiring the digital content, performing feature extraction on the digital content to acquire digital content characteristics, generating an intermediate key based at least on the digital content characteristics and a user's secret information, combining the intermediate key to obtain an encryption key, and embedding a digital content watermark in the digital content based on the encryption key. When the key is submitted to a verifier, the pre-combined key may be provided alone. This avoids the risk of leakage of the key actually used for watermarking. When there is a large amount of media content, a user may locally store only the secret information without storing other intermediate keys or encryption keys. This reduces the user's local storage capacity.

Description

[Technical Field]

[0001] This application claims priority to Chinese Patent Application No. 202210939019.7, entitled "METHOD AND SYSTEM FOR PROCESSING DIGITAL CONTENT, METHOD AND SYSTEM FOR CONFIRMING COPYRIGHT OF DIGITAL CONTENT, AND METHOD AND SYSTEM FOR TRACING DIGITAL CONTENT," filed with the State Intellectual Property Office of China on August 5, 2022, which is incorporated herein by reference in its entirety.

[0002] The present application relates to the field of digital content copyright protection technology, and in particular to a method and system for processing digital content, a method and system for verifying the copyright of digital content, and a method and system for tracking digital content. [Background technology]

[0003] In today's society, as the value of digital content (such as photos, videos, and 3D models) increases, copyright protection for digital content becomes increasingly important. China's copyright market is growing rapidly. With the development of digital science and technology, the amount of digital content, including short videos, long videos, live streaming, internet news, and digital photos, has increased significantly, significantly increasing the proportion of digital content copyrights. As the digital content copyright market grows, digital content copyright issues are becoming increasingly serious. Furthermore, in most infringement cases, it is difficult to collect evidence and verify copyrights, making handling infringement cases inefficient.

[0004] Digital watermarking technology faces security challenges. Digital watermarking is one of the technologies for implementing a strong binding between digital content and copyright information. A watermark containing copyright information is embedded in digital content to verify the copyright. Infringers usually forge keys, extract the watermark from the digital content, and steal the copyright of the digital content. However, the reliability of verifying the copyright of digital content through watermark extraction is low, making it difficult to verify the copyright of digital content. Summary of the Invention

[0005] Embodiments of the present application provide a method and system for processing digital content, a method and system for verifying the copyright of digital content, and a method and system for tracking digital content. A key is combined, and a watermark is embedded in the digital content based on the combined key. Only the pre-combined key is provided to a verifier. A pirate can forge the combined key and extract the watermark, but cannot obtain the pre-combined key. Whether the digital content has been stolen may be determined based on the pre-combined key. This improves the reliability of verifying the copyright of digital content through watermark extraction. [Means for solving the problem]

[0006] According to a first aspect, the present application provides a method for processing digital content, the method comprising the steps of: obtaining the digital content; performing feature extraction on the digital content to obtain digital content features; generating an intermediate key based at least on the digital content features and user secret information; combining at least the intermediate key to obtain an encryption key; and embedding a watermark in the digital content based on the encryption key.

[0007] Feature extraction is performed on the digital content, and a key is generated based on the user's secret information. When the digital content is stolen, features may be extracted directly from the stolen digital content. Whether the digital content has been stolen may be determined based on the user's secret information. When the key is submitted to a verifier, the intermediate key may be provided alone. A pirate may forge the encryption key and extract the watermark, but cannot obtain the intermediate key. Whether the digital content has been stolen may be determined based on the intermediate key. This can also improve the reliability of verifying the copyright of digital content through watermark extraction. When there is a large amount of media content, the user may locally store only the secret information without storing other intermediate keys or encryption keys. This reduces the user's local storage capacity.

[0008] In another possible implementation, the intermediate keys include a first intermediate key and a second intermediate key, and the encryption keys include a first encryption key and a second encryption key. The first intermediate key is obtained based at least on the first digital content characteristic and the first secret information. The second intermediate key is obtained based at least on the second digital content characteristic and the second secret information. The first encryption key is obtained based at least on the first intermediate key. The second encryption key is obtained based at least on the second intermediate key. The first encryption key is used to determine an embedding position of a watermark within the digital content. The second encryption key is used to encrypt the watermark.

[0009] In a possible implementation, the digital content features include a first digital content feature and a second digital content feature, and the user's secret information includes a first secret information and a second secret information. Generating an intermediate key based at least on the digital content features and the user's secret information includes obtaining a first intermediate key based on the first digital content feature and the first secret information, and obtaining a second intermediate key based on the second digital content feature and the second secret information.

[0010] The step of at least combining the intermediate keys to obtain the encryption keys includes the steps of at least combining the first intermediate key to obtain the first encryption key and at least combining the second intermediate key to obtain the second encryption key.

[0011] The step of embedding a watermark in the digital content based on the encryption key includes: determining an embedding position of the watermark in the digital content based on the first encryption key, encrypting the watermark based on the second encryption key, and embedding the encrypted watermark at the embedding position in the digital content; Includes:

[0012] In a possible implementation, the encryption key is further obtained through a binding based on user information.

[0013] In a possible implementation, a method for processing digital content includes: acquiring digital content data, wherein the digital content data includes digital content and copyright information corresponding to the digital content; performing feature extraction on the digital content to obtain feature information of the digital content, wherein the feature information includes a first feature code and a second feature code; generating a first sub-key and a second sub-key based on a user's private key, the first feature code, and the second feature code; outputting an embedding key and a scrambling key by using the first sub-key and the copyright information of the digital content, and the second sub-key and the copyright information of the digital content as inputs of a one-way function, respectively; and embedding a copyright watermark in the digital content in a hidden manner based on the scrambling key and the embedding key to obtain digital content embedded with the copyright watermark.

[0014] For example, the copyright watermark is scrambled based on a scrambling key and a scrambling algorithm, the copyright watermark includes copyright information of the digital content, the embedding position is determined based on the embedding key and the scrambling algorithm, the embedding position indicates the position where the scrambled copyright watermark is embedded in the digital content, and the scrambled copyright watermark is embedded at the embedding position to obtain the digital content with the embedded copyright watermark.

[0015] According to the method for processing digital content in this embodiment of the present application, a copyright watermark containing copyright information is embedded into the digital content, thereby implementing a strong binding between the copyright information and the digital content, and the copyright watermark can also withstand interpretation attacks, which improves the robustness of the copyright watermark.

[0016] Optionally, the one-way function is a hash function. A hash function can compress an input having any length into an output having a fixed length to save storage space. Furthermore, a hash function is irreversible and one-way. This ensures the security of the password.

[0017] In a possible implementation, the feature information includes a singular value feature code, and the first feature code and the second feature code are, respectively, a first singular value feature code and a second singular value feature code obtained through extraction based on the singular value feature code.

[0018] In another possible implementation, generating a first sub-key and a second sub-key based on the user's private key, the first feature code, and the second feature code includes outputting the first sub-key by using the user's private key and the first feature code as inputs to a key derivation algorithm, and outputting the second sub-key by using the user's private key and the second feature code as inputs for the key derivation algorithm.

[0019] For the key derivation algorithm, a suitable key derivation algorithm, such as the standard encryption algorithm AES or the hash algorithm HASH, may be selected based on the actual case, which is not limited in this embodiment of the present application.

[0020] In another possible implementation, the method includes combining the copyright watermark with the embedded digital content into an evidence watermark, the evidence watermark including copyright information for the digital content.

[0021] In this possible implementation, the evidence watermark is further added based on the digital content embedded with the copyright watermark, which implements a double watermarking configuration and ensures the ability to verify the copyright of the information in the digital content itself when the copyright watermark is subjected to an attack that exceeds the upper limit of the robustness of the copyright watermark, providing additional assurance for verifying the copyright of the digital content.

[0022] In another possible implementation, the step of binding the copyright watermark-embedded digital content to the evidence watermark includes the steps of: performing a digest calculation on the copyright watermark-embedded digital content to determine a first digest; and signing the first digest and the copyright information based on the user's private key to determine a first signature. In this way, the evidence watermark is bound to the digital content.

[0023] In this possible implementation, the evidence watermark is bound to a digest of the digital content based on the user's private key to implement a strong binding between the evidence watermark and the digital content, avoid decoupling attacks, and improve the robustness of the evidence watermark.

[0024] In one example, the evidence watermark further includes a first signature, a second signature, and a timestamp. The second signature is obtained by a copyright registration office signing the first signature, the copyright information, and a timestamp after successful signature verification of the first signature. The timestamp includes information about the time when the copyright registration office completed the second signature.

[0025] In another possible implementation, the first digest is a hash value of the digital content embedded with the copyright watermark.

[0026] According to a second aspect, an embodiment of the present application further provides a method for verifying the copyright of digital content. A verifier obtains an intermediate key. The verifier combines at least the intermediate keys to obtain a cryptographic key. The verifier extracts the copyright watermark to be verified from the digital content embedded with the copyright watermark by using the cryptographic key. The verifier determines the ownership of the digital content based on the copyright watermark to be verified.

[0027] In another possible implementation, an attester provides a first subkey, a second subkey, and copyright information to a verifier. The verifier outputs an embedding key and a scrambling key by using the first subkey and copyright information, and the second subkey and copyright information as inputs of a one-way function, respectively. The verifier extracts the copyright watermark from the copyright watermark-embedded digital content based on the embedding key and the scrambling key, and the copyright watermark-embedded digital content is obtained through processing by using the method according to the first aspect. The verifier determines the ownership of the digital content based on the copyright watermark.

[0028] In this possible implementation, a method for verifying the copyright of digital content is provided. Digital content that retains a copyright watermark and is obtained through processing by using the method according to the first aspect is extracted. The copyright watermark embedding scheme in the method according to the first aspect has high robustness and can prevent interpretation attacks. Therefore, it is guaranteed that the copyright watermark can be extracted. Next, copyright information of the digital content is obtained, and copyright verification is performed based on the copyright information. This ensures the reliability of the copyright verification.

[0029] In another possible implementation, the method for verifying the copyright of digital content further includes the verifier not extracting the copyright watermark from the digital content in which the copyright watermark is embedded. In this case, the verifier obtains the evidence watermark. The verifier extracts the copyright information from the evidence watermark.

[0030] The verifier determines the ownership of the content based on the copyright information.

[0031] Specifically, when an attack attempted by an attacker against digital content exceeds the robustness upper limit, such that the copyright cannot be confirmed based on the copyright watermark content obtained by executing a watermark extraction algorithm, if the evidence watermark information held in the digital content is not altered, the evidence watermark can be verified, and copyright information can be extracted from the evidence watermark, it can be proven that the digital content held by the attacker is stolen digital content. In other words, in this possible implementation, when the copyright watermark is subjected to an attack that exceeds the robustness upper limit of the copyright watermark, the double watermark is set to ensure the ability to confirm the copyright of the information in the digital content itself. This provides additional guarantee for confirming the copyright of the digital content.

[0032] In another possible implementation, the verifier extracting the copyright information from the evidence watermark includes the verifier extracting the first signature, the copyright information, the timestamp, and the second signature from the evidence watermark. The verifier performs signature verification on the first signature and the second signature, and if the signature verification is successful, extracts the copyright information from the evidence watermark. This further ensures the security of the information in the evidence watermark through signature verification.

[0033] In another possible implementation, the evidential watermark includes multiple evidential watermarks extracted from digital content uploaded by parties involved in a copyright dispute regarding the digital content, and ownership of the digital content is further associated with the timestamps of the evidential watermarks.

[0034] For example, when the evidential watermark is also attacked, specifically, copyright information cannot be extracted from the evidential watermark, and the parties involved in the copyright dispute are required to upload digital content. Evidence watermarks are extracted from the digital content uploaded by the parties involved in the copyright dispute, respectively. Time stamps are extracted from the evidential watermarks corresponding to the digital content uploaded by the parties involved in the copyright dispute. The evidential storage times of the digital content of the parties involved in the copyright dispute are determined based on the time stamps. The user corresponding to the digital content with the earliest evidential storage time is determined to be the copyright owner of the digital content.

[0035] In other words, if the evidence watermark of the digital content is also changed, the user needs to provide the original digital content that retains the evidence watermark and has a copyright conflict, and the copyright is verified based on the evidence information and the evidence storage time, which further provides a guarantee for verifying the copyright of the digital content.

[0036] According to a third aspect, an embodiment of the present application further provides a method for processing digital content, including the steps of obtaining digital content embedded with a copyright watermark and binding tracking credentials to the digital content. The tracking credentials include tracking information and verifiable credentials. The tracking information is metadata related to the digital content, and includes a digest of the digital content as a basic material for tracking. The verifiable credentials are a signature obtained by signing the digest of the tracking information based on a user's private key.

[0037] In this possible implementation, a copyright watermark is embedded in the digital content to implement a strong binding between the copyright and the digital content, and the tracking credential is bound to the digital content based on a user's signature key. Therefore, the copyright information, the tracking credential, and the digital content are bound, and an attacker cannot separate them. Even if the digital content is stolen, the administrator can easily determine the copyright ownership and the original infringer through tracking based on the copyright information and the tracking credential.

[0038] In another possible implementation, binding the tracking credentials to the digital content includes determining the tracking information based on a digest of the digital content, and signing the tracking information based on the user's private key to determine verifiable credentials.

[0039] In another possible implementation, the tracking information further includes at least one of a preview of the digital content and an identification of a user, the user being a copyright owner or grantee of the digital content.

[0040] In this possible implementation, the tracking information further includes a preview of the digital content and user identification information, so that the user can know partial information of the digital content based on the tracking information, which improves the user experience.

[0041] In another possible implementation, the tracking information further includes authorization information, the authorization information including authorization credentials and an authorization signature, the authorization credentials verifying that authorization for the digital content has been obtained, the authorization signature being obtained by signing the authorization credentials by the copyright owner of the digital content.

[0042] In another possible implementation, the tracking credentials include a first tracking credential and a second tracking credential. The first tracking credential is generated for a copyright owner of the digital content. The second tracking credential is generated for a grantee of the digital content or for processing the digital content. The second tracking credential includes a digest of the first tracking credential.

[0043] In another possible implementation, the digital content embedded with the copyright watermark is obtained through a process by using the method according to the first aspect.

[0044] According to a fourth aspect, an embodiment of the present application further provides a method for tracking digital content, comprising: acquiring digital content, wherein the digital content is acquired through processing by using the method according to the third aspect; determining, based on the digital content, tracking credentials associated with the digital content; and performing tracking on the digital content based on the tracking credentials.

[0045] According to a fifth aspect, an embodiment of the present application further provides a system for verifying copyright of digital content and tracking the digital content, including at least a feature extraction module, a detection module, a copyright verification module, a tracking module, and a processing module. The feature extraction module is configured to extract features of the digital content. The detection module is configured to compare the extracted features of the digital content with features in a feature database to determine whether the feature database contains features similar to the features of the digital content. The copyright verification module is configured to extract copyright information of the digital content and determine ownership of the digital content based on the copyright information. The tracking module is configured to extract tracking credentials of the digital content and track the digital content based on the tracking credentials to determine infringing digital content. The processing module is configured to take corresponding action against the owner of the infringing digital content and / or remove the digital content from a chain of trust to which the infringing digital content belongs.

[0046] In this possible implementation, a system for verifying copyright of digital content and tracking digital content is provided that ensures both the ability to verify copyright of digital content and the ability to track it after copyright verification (e.g., to determine the original infringer through tracking).

[0047] In a possible implementation, the digital content is obtained through processing by using the method according to the first aspect and / or the method according to the third aspect. After the digital content has been processed by using the method according to the first aspect and / or the method according to the third aspect, the ability to verify the copyright of the digital content and the traceability of the digital content are improved.

[0048] In a possible implementation, the copyright information includes a copyright watermark and / or an evidence watermark corresponding to the digital content. A double watermarking scheme is used to further ensure the ability to verify the copyright of the digital content.

[0049] In a possible implementation, the system for verifying the copyright of digital content and tracking digital content further includes a digital content generation and upload module configured to process the digital content by using the method according to the first aspect and / or the method according to the third aspect, perform verification of the processed digital content, and upload the processed digital content to the system if the verification is successful. The digital content generation and upload module in the system enables the system to automatically embed a copyright watermark into the digital content, implementing a strong coupling between the evidence watermark and the digital content, and between the digital content and tracking credentials, to ensure functionality of digital content copyright verification and cross-platform copyright verification and tracking. Furthermore, the digital content generation and upload module verifies the digital content during upload to ensure the accuracy of the digital content's generation.

[0050] In a possible implementation, the system for verifying copyright of digital content and tracking digital content further includes an authorization and chain of trust establishment module configured to generate authorization information in response to an authorization request, process the recreated digital content by using the method according to the first aspect and / or the method according to the third aspect to determine second digital content data, and determine the third digital content data based on the authorization information and the second digital content.

[0051] Optionally, the authorization information includes authorization credentials and an authorization signature.

[0052] The system for verifying copyright of digital content and tracking digital content in this embodiment of the present application solves the problem that copyright cannot be verified when media platforms use various evidence storage systems and digital content is stolen across platforms. The system can accurately verify copyright across platforms based on the dual guarantee of copyright watermarks and evidence watermarks, provided that a qualified copyright registration office is used. Based on a chain-of-trust mechanism, the original copyright infringer is accurately determined through tracking, and the entire infringement chain is identified. The copyright registration office is only responsible for registration and is not involved in copyright verification inquiries, therefore, it has a small computational load. Based on the copyright watermark scheme, in most scenarios, the system can still provide copyright evidence for copyright disputes that are not registered with the same copyright registration office to verify copyright.

[0053] According to a sixth aspect, an embodiment of the present application provides a computing device including a memory and a processor, wherein the memory stores instructions that, when executed by the processor, implement a method according to the first aspect, a method according to the second aspect, a method according to the third aspect, and / or a method according to the fourth aspect.

[0054] According to a seventh aspect, an embodiment of the present application provides a computer-readable storage medium storing a computer program which, when executed by a processor, implements a method according to the first aspect, a method according to the second aspect, a method according to the third aspect, and / or a method according to the fourth aspect.

[0055] According to an eighth aspect, an embodiment of the present application further provides a computer program or computer program product, the computer program or computer program product comprising instructions that, when executed, enable a computer to perform a method according to the first aspect, and / or a method according to the second aspect, and / or a method according to the third aspect, and / or a method according to the fourth aspect.

[0056] According to a ninth aspect, an embodiment of the present application further provides a chip including at least one processor and a communication interface, wherein the processor is configured to perform a method according to the first aspect, and / or a method according to the second aspect, and / or a method according to the third aspect, and / or a method according to the fourth aspect. [Brief explanation of the drawings]

[0057] [Figure 1a] 1 is a flow chart of a method for processing digital content according to an embodiment of the present application. [Figure 1b] 1 is a flow chart of a method for processing digital content according to an embodiment of the present application. [Figure 2a] 1 is a diagram of a process for embedding a copyright watermark in digital content by using a method for processing digital content according to an embodiment of the present application; [Figure 2b] 1 is a diagram of a process for embedding a copyright watermark in digital content by using a method for processing digital content according to an embodiment of the present application; [Figure 3] FIG. 1 is a diagram of an implementation process of a dual watermarking scheme for digital content. [Figure 4] FIG. 1 is a diagram of the process of extraction of copyright watermark by a verifier. [Figure 5] FIG. 1 is a diagram of combined digital content, copyright information, and tracking credentials. [Figure 6]A diagram of the complete digital content data obtained by packaging digital content with embedded copyright watermarks, tracking credentials, and evidence watermarks. [Figure 7] 1 is a diagram of the architecture of a system for verifying copyright of digital content and tracking digital content according to one embodiment of the present application. [Figure 8] 1 is a diagram of the creation and review of digital content in a system for verifying digital content copyright and tracking digital content according to one embodiment of the present application. [Figure 9] 1 is a schematic flow chart of verifying copyright of digital content and tracking digital content in a system for verifying copyright of digital content and tracking digital content according to an embodiment of the present application; [Figure 10] 1 is a diagram of the creation and uploading of digital content in a system for verifying copyright of digital content and tracking digital content according to an embodiment of the present application. [Figure 11] FIG. 1 is a diagram illustrating digital content authorization and establishing a chain of trust in a system for verifying copyright of digital content and tracking digital content according to an embodiment of the present application. [Figure 12] 1 is a diagram of copyright verification and tracking of copyright disputes discovered through fingerprint detection in a system for verifying copyright of digital content and tracking digital content according to one embodiment of the present application. [Figure 13] 1 is a diagram of copyright verification and tracking of copyright disputes resulting from user reports in a system for verifying copyrights of digital content and tracking digital content according to one embodiment of the present application; [Figure 14] 1 is a diagram of the structure of a computing device according to one embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0058] The following further describes the technical solutions of the present application with reference to the accompanying drawings and embodiments.

[0059] Embedding copyright information into digital content in the form of digital watermarks is a powerful coupling method for digital copyright. Security design and robustness research of watermarking schemes are two central directions. Robustness is the ability of a typical watermarking scheme to resist malicious watermark removal under various signal processing attacks. Different watermarking schemes have different attack resistance capabilities. Security is the ability of a watermarking scheme to resist watermark removal attacks when the watermarking scheme is disclosed. Security design of watermarks is a necessary function of watermarking as a copyright protection measure.

[0060] Furthermore, as the value of digital content increases, large-scale reproduction and propagation of digital content may occur, which may lead to various copyright infringements. In practical applications, a complete system for verifying the copyright of digital content and tracking digital content needs to be used to identify the propagation process of digital content, track the entire process, and discover malicious participants in the process to solve various copyright issues related to the propagation and reproduction of digital content.

[0061] However, some conventional copyright protection technologies have the following problems. 1. Digital watermarking technology faces security challenges. Digital watermarking is one of the technologies for implementing a strong binding between digital content and copyright information. A watermark containing copyright information is embedded in digital content to verify the copyright. Although watermark embedding methods for various types of digital content can vary, the watermark embedding method needs to be disclosed when used for copyright protection, and a key needs to be submitted for copyright verification. Therefore, in addition to attacks on robustness, digital watermarking may also be at risk of key leakage and forged key-based interpretation attacks. 2. Evidence-based copyright verification mode is susceptible to attacks. Storing the hash value of digital content as evidence in a reliable copyright protection system is a means of copyright verification because hash algorithms are collision-resistant. However, copyright verification based on hash evidence cannot withstand tampering attacks. An attacker may steal digital content from another user and tamper with the digital content to some extent. In this case, the copyright cannot be verified. 3. Traditional copyright protection systems cannot simultaneously guarantee the ability to verify the copyright of digital content and the ability to determine the original infringer through tracking after copyright verification.

[0062] The embodiments of the present application provide a method and system for processing digital content, a method and system for verifying the copyright of digital content, and a method and system for tracking digital content, which have the ability to identify copyright conflicts, provide full-cycle copyright verification for cross-platform data, and determine the original infringer and related profit chain through tracking.

[0063] Currently, copyright infringement involving digital content occurs in many scenarios. For example, in a decoupling attack scenario, an infringer steals digital content, disguises the digital content as the infringer's copyrighted property, and generates complete digital content information. In a cross-platform copyright dispute scenario, an infringer steals a copyright owner's digital content from Platform B, generates related listings and additional information, and then publishes the listings and additional information on Platform A. Even if the copyright owner discovers and reports the digital content after multiple authorized creations, it is still difficult for Platform A to determine the copyright ownership of the digital content.

[0064] A method to resist such decoupling attacks is to implement a strong binding between copyright information and digital content to prevent pirates from erasing all copyright-related information when stealing digital content. A common solution is to add a digital watermark to digital content to bind the digital content to the copyright information and use a key to hide the watermark information. However, the embedding process of a watermarking scheme is usually a simple computational operation and is reversible. Therefore, a forged-key-based interpretation attack may occur. Some information is extracted from the digital content based on a forged key, and then the key value is adjusted to interpret the information as the attacker's watermark signature. Furthermore, key leakage may occur during the implementation of the watermarking scheme. Furthermore, malicious modifications to the digital content may cause the copyright watermark to be unable to be extracted from the digital content or the copyright to be unable to be verified based on the extracted watermark. Embodiments of the present application provide a watermarking scheme to resist interpretation attacks and avoid key leakage, to solve the problem that copyright cannot be verified due to subversion attacks.

[0065] An administrator may verify the copyright of digital content based on the binding between the digital content and copyright information. However, tracking credentials associated with the digital content still need to be used to determine the original infringer through tracking. Therefore, based on a digital watermarking scheme for copyright protection, an embodiment of the present application provides a solution for binding digital content, copyright information, and tracking credentials. In this solution, a copyright watermark is embedded in the digital content to implement a strong binding between the copyright and the digital content, and the evidential watermark and tracking credentials are separately bound to the digital content based on a user's signature key. In this way, the copyright information is associated with each other, and the copyright information and tracking credentials are bound to the digital content.

[0066] The present application also provides a full-cycle, efficient, and complete system for verifying the copyright of digital content and tracking digital content. The system includes three parts: a digital content fingerprint extraction and query system for copyright dispute detection, a watermark generation and authentication system for copyright verification in copyright disputes, and an authorization and chain of trust mechanism for determining the original infringer through tracing. This ensures the integrity and security of full-cycle copyright information protection and digital content authorization in the system, provides the ability to trace after copyright verification, and avoids the risks of copyright infringement such as decoupling attacks.

[0067] The following describes in detail several solutions for digital content in embodiments of the present application: One embodiment of the present application provides a method for processing digital content, in which a copyright watermark containing the copyright information of the digital content is embedded in the digital content to implement a strong binding between the copyright information and the digital content.

[0068] 1(a) and 1(b) are each a flowchart of a method for processing digital content according to an embodiment of the present application. The method may be implemented by any apparatus, device, platform, or device cluster having computer functionality. The specific computer device for implementing the method is not particularly limited in this embodiment of the present application, and an appropriate computer device may be selected according to the requirements for implementing the method.

[0069] As shown in FIG. 1(a) and FIG. 2(a), the method for processing digital content includes at least steps S10 to S60.

[0070] Step S1: Perform feature extraction on the digital content to obtain the digital content features.

[0071] Digital content is text, images, audio, video, or other content that exists in digital form. Digital content may be stored on a digital carrier such as a compact disc or hard disk drive, or propagated over a network or other means.

[0072] The digital content features may be digital fingerprint features, singular value features, or other stable features, so that the same features can still be extracted after the digital content has been watermarked or attacked.

[0073] The features of the digital content may be extracted by using multiple methods, for example, the features of the digital content are extracted by using machine learning methods, or the features of the digital content are extracted by using pre-set extraction rules.

[0074] For example, digital content is input to a trained feature extraction model and features of the digital content are output, or operators are obtained by summarizing a large amount of prior knowledge and features of the digital content are extracted by using the operators, or singular values of the digital content are calculated and feature codes of the digital content are extracted from the singular values and the feature codes are used as features of the digital content.

[0075] It should be noted that the specific feature extraction method of the digital content is not limited in this application, and a suitable feature extraction method may be selected according to actual requirements.

[0076] There may be one or more digital content features. In one embodiment, the digital content features include a first digital content feature and a second digital content feature. The first digital content feature and the second digital content feature may be the same feature or different features.

[0077] Step S2: Generate an intermediate key based at least on the digital content characteristics and the user's secret information.

[0078] In some embodiments, the user's secret information may be the user's private key, a random number generated locally by the user, or other secret information of the user. The user's secret information is stored locally by the user. During copyright verification, the user is required to submit the secret information to the verifier.

[0079] In one embodiment, the intermediate key may be generated based on a key generation algorithm, and the intermediate key is output by using both the user's secret information and the digital content characteristics as inputs to the key generation algorithm. The intermediate key can also be a sub-key.

[0080] In one embodiment, the intermediate key is generated based on the copyright information of the digital content, the digital content characteristics, and the user's secret information. The intermediate key may be output by using all of the copyright information of the digital content, the digital content characteristics, and the user's secret information as inputs to a key generation algorithm. The copyright information IC is information that can clearly indicate copyright ownership, such as the user's ID (copyright owner) or the user's public key, or other content that can describe copyright ownership.

[0081] There may be one or more intermediate keys. In one embodiment, the intermediate keys include a first intermediate key and a second intermediate key. The first intermediate key is obtained based at least on the first digital content characteristic and the first secret information. The second intermediate key is obtained based at least on the second digital content characteristic and the second secret information. In one embodiment, the first secret information and the second secret information may be the same or different secret information. For example, the first secret information and the second secret information may be a user's secret key.

[0082] In one embodiment, a first intermediate key may be output by using the first digital content feature and the first secret information as inputs to a first key generation algorithm, and a second intermediate key may be output by using the second digital content feature and the second secret information as inputs to the first key generation algorithm. Specifically, generating an intermediate key based at least on the digital content features and the user's secret information includes: obtaining a first intermediate key based on a first digital content feature and the first secret information, and obtaining a second intermediate key based on a second digital content feature and the second secret information, where the first key generation algorithm and the second key generation algorithm may be the same or different, for example, the key generation algorithm may be any key derivation algorithm, such as the standard encryption algorithm AES or the hash algorithm, and the user may select an appropriate key derivation algorithm according to actual requirements; outputting the first intermediate key by using the first secret information and the first digital content feature as inputs for the key derivation algorithm; and outputting the second intermediate key by using the second secret information and the second digital content feature as inputs for the key derivation algorithm.

[0083] Step S3: Combine at least the intermediate keys to obtain the encryption key.

[0084] Binding is a processing method to prevent the intermediate key from being forged. The encrypted data can be obtained through binding to the intermediate data, but the intermediate data cannot be obtained through a reverse process on the encrypted data. For example, the intermediate data is processed by using a one-way function. In one embodiment, the intermediate key may be hashed to obtain the encryption key, which is a hash value of the intermediate key.

[0085] In one embodiment, the encryption key may be obtained by combining both the intermediate key and the user information. Specifically, the user information may be added during the combining, and the encryption key may be output by using both the user information and the intermediate key as inputs to a one-way function. In other words, the encryption key may be obtained based on the intermediate key and the user information. For example, the encryption key may be a hash value of data obtained by combining the intermediate key and the user information, or the encryption key may be data obtained by combining the hash value of the intermediate key and the hash value of the user information, or the encryption key may be a hash value of data obtained by combining the hash value of the intermediate key and the hash value of the user information. The user information may be copyright information of the digital content.

[0086] In one embodiment, the encryption key includes a first encryption key and a second encryption key, where the first encryption key is obtained based at least on the first intermediate key, and the second encryption key is obtained based at least on the second intermediate key. Specifically, combining the intermediate keys includes combining the first intermediate key to obtain the first encryption key and combining the second intermediate key to obtain the second encryption key. The combination of the first intermediate key and the second intermediate key will not be described in detail here. In one embodiment, the first encryption key may be an embedding key, and the second encryption key may be a scrambling key.

[0087] Step S4: Embed a watermark into the digital content based on the encryption key.

[0088] In one embodiment, the watermark may be encrypted using an encryption key, and then the encrypted watermark is embedded in the digital content. In one embodiment, the embedding location of the watermark within the digital content may be encrypted using an encryption key. In one embodiment, both the embedding location of the digital content and the watermark may be encrypted.

[0089] In one embodiment, the watermark includes information indicative of user identity, such as a personal ID, user identifier, logo, pattern, or other information that may indicate user identity, and may also be referred to as copyright information or a copyright watermark.

[0090] In one embodiment, the first encryption key is used to determine an embedding position of the watermark in the digital content, and the second encryption key is used to encrypt the watermark. Specifically, embedding the watermark in the digital content based on the encryption key includes determining an embedding position of the watermark in the digital content based on the first encryption key, encrypting the watermark based on the second encryption key, and embedding the encrypted watermark at the embedding position in the digital content.

[0091] Feature extraction is performed on the digital content, and a key is generated based on the user's secret information. When the digital content is stolen, features may be extracted directly from the stolen digital content. Whether the digital content has been stolen may be determined based on the user's secret information. When the key is submitted to a verifier, the combined intermediate key may be provided alone. A trespasser forges an encryption key and extracts the watermark, but cannot obtain the intermediate key. The verifier calculates an encryption key based on the intermediate key and checks whether the encryption key is the same as the forged encryption key to determine whether the digital content has been stolen. When there is a large amount of media content, the user may locally store only the secret information without storing other intermediate keys or encryption keys. This reduces the user's local storage capacity.

[0092] As shown in FIG. 1(b), in one embodiment, the method for processing digital content includes at least steps S101 to S106.

[0093] Step S101: Perform feature extraction on the digital content to obtain feature information of the digital content, where the feature information includes a first feature code and a second feature code.

[0094] The interpretation of the digital content and feature extraction is the same as that of the terminology in FIG. 1(a). The feature information is the same as the digital content feature in the previous embodiment. The first feature code and the second feature code are extracted from the digital content feature. For example, the digital content feature is a feature code extracted from the singular value of the digital content, and may also be called a singular value feature code. Feature codes at different positions within the singular value feature code (e.g., the first 1 / 3 and the last 1 / 3 of the singular value feature code) are separately extracted as a first feature code FC1 and a second feature code FC2 according to a preset rule.

[0095] Step S102: Generate a first sub-key and a second sub-key based on the user's private key, the first feature code, and the second feature code.

[0096] The first subkey Subkey1 is output by using FC1 and the user's private key SK as inputs to the key derivation algorithm KEY_GEN. For example, Subkey1 = KEY_GEN(SK,FC1). The second subkey Subkey2 is output by using FC2 and the user's private key SK as inputs to the key derivation algorithm KEY_GEN. For example, Subkey2 = KEY_GEN(SK,FC2). The key derivation algorithm KEY_GEN may be any key derivation algorithm, such as the standard encryption algorithm AES or the hash algorithm HASH. The user may select an appropriate key derivation algorithm according to actual requirements.

[0097] Step S103: Output an embedding key and a scrambling key by using the first sub-key and the copyright information of the digital content, and the second sub-key and the copyright information of the digital content as inputs of a one-way function, respectively.

[0098] The first subkey Subkey1 and the digital content copyright information IC are input to a one-way function, for example, a HASH function, HASH(IC||Subkey1), to obtain an embedding key. The second subkey Subkey2 and the digital content copyright information IC are input to a one-way function, for example, a HASH function, HASH(IC||Subkey2), to obtain a scrambling key.

[0099] The copyright information IC can be understood to be information that can clearly indicate copyright ownership, such as a user's ID (copyright owner) or a user's public key, or other content that can describe copyright ownership. The copyright information is sometimes called a watermark.

[0100] Step S104: Scramble the copyright watermark according to the scrambling key and the scrambling algorithm, where the copyright watermark contains the copyright information of the digital content.

[0101] For example, a scrambling sequence of the copyright watermark is calculated by using a scrambling key and a scrambling algorithm, and the copyright watermark is scrambled based on the scrambling sequence. In this way, scrambling encryption is performed on the copyright watermark to obtain the encrypted copyright watermark that needs to be embedded.

[0102] The scrambling algorithm may be one of a plurality of scrambling algorithms in a chaotic map, such as a logistic map and a shear map, or may be another suitable scrambling algorithm, which is not limited in this embodiment of the present application.

[0103] Step S105: Determine an embedding position based on the embedding key and the scrambling algorithm, where the embedding position represents the position where the scrambled copyright watermark is embedded in the digital content.

[0104] A frequency domain transform is performed on the digital content to obtain a frequency domain coefficient matrix corresponding to the digital content, and an embedding position of the copyright watermark in the frequency domain coefficient matrix is calculated by using an embedding key and a scrambling algorithm (e.g., a logistic map).

[0105] Frequency domain transformations may be performed on digital content in a number of ways, for example, Discrete Cosine Transform (DCT) or Discrete Fourier Transform.

[0106] Step S106: Embed the scrambled copyright watermark at the embedding position to obtain the digital content embedded with the copyright watermark.

[0107] The copyright watermark is embedded at the calculated embedding location in a frequency domain coefficient matrix corresponding to the digital content based on a watermark embedding algorithm, and then an inverse frequency domain transform is performed to obtain the digital content embedded with the copyright watermark.

[0108] There are several watermark embedding algorithms, such as the quantization index modulation (QIM) method for watermark embedding and the multiplication embedding method for watermark embedding.

[0109] The method for processing digital content in this embodiment of the present application can also be called a watermark embedding solution for digital content (see Figure 2(b) for the process of embedding copyright watermark). By using a method for deriving an embedding key and a scrambling key by combining the copyright information of the digital content and the user's private key with the content characteristics of the digital content, a one-way function, for example, a HASH function, is added to the key derivation in the watermarking scheme to build the security of the copyright watermark based on the collision-resistant function of the HASH function. This improves the security of using copyright watermark.

[0110] For the watermark embedding scheme for digital content, an embodiment of the present application further provides a method for verifying the copyright of the digital content. A verifier obtains an intermediate key. The verifier at least combines the intermediate keys to obtain an encryption key. The verifier extracts the copyright watermark to be verified from the copyright watermark-embedded digital content by using the encryption key. The verifier determines the ownership of the digital content based on the copyright watermark to be verified.

[0111] In one embodiment, the attestor provides a first subkey Subkey1, a second subkey Subkey2, and copyright information to a verifier. The verifier outputs an embedding key and a scrambling key by using the first subkey and the copyright information, and the second subkey and the copyright information as inputs to a one-way function (e.g., a HASH function), respectively. The verifier extracts the copyright watermark from the digital content based on the embedding key and the scrambling key, and determines the ownership of the digital content based on the copyright information contained in the copyright watermark to verify the copyright of the digital content.

[0112] Specifically, during copyright verification, a user submits Subkey1 and Subkey2 output by the key derivation algorithm (i.e., the first HASH function shown in Figure 2(b)), and the user only needs to remember the user's private key SK, which reduces the key storage capacity and improves security.

[0113] Furthermore, the watermark embedding scheme for digital content in this embodiment of the present application can withstand forged key-based interpretation attacks and has high robustness.

[0114] For example, when obtaining a watermarked digital content P*, a pirate may use a disclosed one-way function (e.g., a HASH function) to calculate an embedding key based on the pirate's copyright information and a forged Subkey1, extract some forged-key-based watermark information from the digital content, and then forge a related scrambling key according to the watermark scrambling rules of the disclosed algorithm, so that a watermark corresponding to the pirate's copyright information can be obtained by converting the watermark information. In this way, the pirate obtains a watermark embedding key and a watermark scrambling key based on the forged Subkey1 and the pirate's copyright information IC. However, Subkey2, which is specifically an input for the HASH algorithm and needs to be provided to the verification authority, cannot be calculated based on the scrambling key. Similarly, the pirate cannot calculate the corresponding IC or the corresponding Subkey1 based on the forged Subkey2. Therefore, an attacker can only attempt to remove the watermark information through a brute force attack, but cannot directly steal the copyright. The disclosed watermarking algorithm cannot withstand such attacks.

[0115] In order to ensure the security of the copyright information of digital content, one embodiment of the present application further provides a double watermarking scheme for digital content. When the copyright watermark is subjected to an attack that exceeds the upper limit of the robustness of the copyright watermark, evidence watermark information is added to the metadata of the digital content embedded with the copyright watermark to ensure the ability to verify the copyright of the information in the digital content itself. Therefore, a strong binding between the digital content and the copyright information is implemented in various cases.

[0116] FIG. 3 is a diagram of an implementation process of a dual watermarking scheme for digital content.

[0117] The user side extracts features from the digital content, and then extracts two important features FC1 and FC2 from the features. The features extracted from the digital content may be digital fingerprint features or other stable information, so that the information can still be extracted even after the digital content is watermarked or attacked.

[0118] The user side performs calculations through the key derivation algorithm KEY_GEN by using FC1, FC2 and the user's copyright key SK as inputs, i.e., Subkey1=KEY_GEN(SK,FC1), and Subkey2=KEY_GEN(SK,FC2). The specific KEY_GEN algorithm is selected by the user side and may be a standard encryption algorithm AES, a hash algorithm HASH, etc.

[0119] The user side uses Subkey1, Subkey2 and the copyright information IC to calculate the watermark embedding key with HASH(IC||Subkey1) through the disclosed standard HASH algorithm as follows, and calculates the watermark scrambling key with HASH(IC||Subkey2) as follows:

[0120] The user side performs scrambling encryption on the watermark signature by using a watermark scrambling key to obtain the watermark information that needs to be embedded, calculates the embedding position of the watermark in the frequency domain coefficient matrix of the digital content P by using an embedding key, embeds the watermark information at the calculated position in the frequency domain coefficient matrix based on the watermark embedding algorithm, and performs inverse frequency domain transformation to obtain the watermark-embedded digital content P*.

[0121] The user side calculates the hash value Q of P*, signs Q and the copyright information IC, and then sends the signature result S, the hash value Q, and the copyright information IC to the copyright registration office for evidence registration, in order to bind the evidence watermark to the watermarked digital content P*.

[0122] The copyright registration office receives an evidence storage request from the user side, signs S, IC, and timestamp T after successful signature verification, and sends the signature result SIGN and corresponding signature information to the user.

[0123] After receiving the information and successfully verifying the signature, the user uses the relevant information (S, IC, T, and SIGN) as an evidence watermark for the digital content P*.

[0124] It can be understood that the copyright watermark is embedded in the digital content in a covert manner, and the evidential watermark is associated with and bound to the digital content (e.g., packaged and propagated with the digital content). Specifically, the evidential watermark exists as data associated with the digital content, and the complete digital content data includes the digital content with the embedded copyright watermark and data associated with the digital content, with the evidential watermark being part of the data associated with the digital content.

[0125] For the double watermarking scheme of digital content, an embodiment of the present application further provides a corresponding method for verifying the copyright of digital content: if a verifier does not extract the copyright watermark from the digital content embedded with the copyright watermark, the verifier obtains the evidence watermark, extracts the copyright information from the evidence watermark, and determines the ownership of the digital content based on the copyright information.

[0126] The process of extracting the copyright watermark by the verifier can be seen in Figure 4. The user sends Subkey1, Subkey2, and copyright information IC as copyright evidence to the verifier (verification authority). The verification authority calculates the watermark embedding key and watermark scrambling key by HASH(IC||Subkey1) and HASH(IC||Subkey2), respectively, as follows: Based on the disclosed watermarking scheme, the verification authority extracts the copyright watermark from the digital content P* by using the watermark embedding key and watermark scrambling key, and verifies whether the copyright watermark belongs to the user declared in IC.

[0127] When the copyright watermark is destroyed by an attack, specifically, when the copyright watermark cannot be extracted from the digital content in which the copyright watermark is embedded, the verification authority obtains the evidence watermark, extracts copyright information from the evidence watermark, and determines the ownership of the digital content based on the extracted copyright information.

[0128] For example, when the verification authority does not extract copyright watermark information from the digital content, the verification authority obtains the evidence watermark associated with the digital content, extracts (S, IC, SIGN) from the evidence watermark, calculates Sign.ver(VK1, S, HASH(P*)) and Sign.ver(VKT, SIGN, S||IC||T), and verifies whether Sign.ver(VK1, S, HASH(P*)) and Sign.ver(VKT, SIGN, S||IC||T) are correct. If Sign.ver(VK1, S, HASH(P*)) and Sign.ver(VKT, SIGN, S||IC||T) are correct, the verification is successful, and the verification authority determines that the copyright information in the evidence watermark was generated correctly. In this case, the verification authority verifies the copyright by using the copyright information extracted from the evidence watermark.

[0129] When the evidential watermark is also attacked, specifically, copyright information cannot be extracted from the evidential watermark, and the parties involved in the copyright dispute are required to upload digital content. Evidence watermarks are extracted from the digital content uploaded by the parties involved in the copyright dispute, respectively. Time stamps are extracted from the evidential watermarks corresponding to the digital content uploaded by the parties involved in the copyright dispute. The evidential storage times of the digital content of the parties involved in the copyright dispute are determined based on the time stamps. The user corresponding to the digital content with the earliest evidential storage time is determined to be the copyright owner of the digital content.

[0130] According to the double watermarking scheme provided in this embodiment of the present application, when the attack attempted by an attacker on digital content exceeds the robustness upper limit, so that the copyright cannot be confirmed based on the copyright watermark content obtained by running a watermark extraction algorithm, if the evidence watermark information held in the digital content is not changed, the evidence watermark can be verified, and the copyright information can be extracted from the evidence watermark, it can be proven that the digital content held by the attacker is stolen digital content. If the evidence watermark of the digital content is also changed, the user needs to provide the original digital content bearing the evidence watermark, and the copyright will be confirmed based on the evidence information and the evidence storage time.

[0131] The double watermarking scheme provided in this embodiment of the present application further includes evidence watermarking. Specifically, absolute assurance is added to the watermark-based copyright verification function through evidence storage, which is crucial for the final copyright verification in practical applications.

[0132] In cases of infringement caused by exact copying, the evidence storage system can quickly verify the copyright through simple calculation. However, the connection between the evidence and the digital content is weak, and the digital content itself does not contain copyright information. If the digital content is modified by an infringer, the copyright verification process may involve a complex litigation process. The dual watermarking scheme provided in this embodiment of the present application combines the evidence storage function and the strong binding function. In cases of simple copy infringement, the copyright can be verified based on digital fingerprint detection or copyright information stored as evidence. Under attacks within the robustness function of the watermarking scheme, the copyright can be verified by extracting the copyright watermark. Under attacks that exceed the robustness upper limit of the watermark, the copyright can be verified based on the evidence information.

[0133] Therefore, the dual watermarking scheme provided in this embodiment of the present application provides better protection than common watermarks and provides more comprehensive and extensive copyright verification capabilities than evidence storage systems.

[0134] To implement tracking of digital content, an embodiment of the present application further provides a method for processing digital content. This method may also be referred to as a method for combining digital content, copyright information, and tracking credentials. This method includes first obtaining digital content embedded with a copyright watermark and then combining tracking credentials with the digital content. The tracking credentials include tracking information and verifiable credentials. The tracking information is metadata associated with the digital content, including a digest of the digital content as the basic material for tracking. The verifiable credentials are a signature obtained by using a user's private key and a digest generated based on the tracking information.

[0135] A solution for binding tracking credentials to digital content is as follows: a digest of the digital content embedded with a copyright watermark is calculated to obtain a first digest; a digest calculation is performed on the tracking information by using the first digest as part of the tracking information to obtain a second digest; a user signs the second digest based on the user's private key to obtain a verifiable credential; and the tracking information and the verifiable credential constitute the tracking credential.

[0136] Preferably, a specific implementation of calculating the digest of the copyright watermarked digital content may be hashing, for example, the copyright watermarked digital content is hashed to obtain a hash value of the copyright watermarked digital content, the hash value being a digest of the copyright watermarked digital content.

[0137] In this embodiment of the present application, a copyright watermark is embedded in the digital content to implement a strong binding between the copyright and the digital content, and the tracking credential is bound to the digital content based on the user's signature key. Therefore, the copyright information, the tracking credential, and the digital content are bound, and an attacker cannot separate them. Even if the digital content is stolen, the administrator can easily determine the copyright ownership and determine the original infringer through tracking based on the copyright information and the tracking credential.

[0138] Optionally, the copyright information of the digital content further includes an evidential watermark. Specifically, the digital content may be a digital content obtained through a process based on a double watermarking scheme. In this way, the digital content is bound to the evidential watermark.

[0139] FIG. 5 is a diagram of combined digital content, copyright information, and tracking credential information. The copyright information of the digital content includes a copyright watermark and an evidence watermark. The copyright watermark is embedded in the digital content by using a watermark embedding scheme provided in an embodiment of the present application to implement a strong binding. The evidence watermark, signed and approved by a registration authority, is bound by using a user's signature key. The tracking information may include some details of the digital content, the creator's identification information, and other information. The tracking information is bound to the digital content based on the user's signature key. In this way, the copyright information is associated with each other, and the copyright information and tracking credential information are bound to the digital content.

[0140] In one example, in addition to a digest of the digital content, the tracking information further includes a preview of the digital content and / or related information of the user (e.g., the user's identity). The verifiable credential is obtained by the user by signing the digest of the tracking information by using the user's private signature key. The digital content is bound to the tracking credential based on a hash of the digital content stored in the tracking information and on the signature scheme used in the verifiable credential.

[0141] Optionally, when the copyright owner of the digital content authorizes another user to recreate or propagate the digital content, the other user further generates a second tracking credential for the created digital content. A first tracking credential is generated for the copyright owner of the digital content. The second tracking credential is generated for a grantee of the digital content or for processing the digital content. The second tracking credential includes a digest of the first tracking credential, thereby binding the second tracking credential to the first tracking credential.

[0142] In another example, the tracking information includes authorization information, and the authorization information includes authorization credentials and an authorization signature. The authorization credentials prove that authorization for the digital content has been obtained. The authorization signature is obtained by signing the authorization credentials by the copyright owner of the digital content. The authorization information may also be used as tracking information. In other words, the tracking information may also include authorization information.

[0143] As shown in FIG. 6, the complete digital content data includes data obtained by packaging digital content embedded with a copyright watermark, tracking credentials, and evidence watermarks. The tracking credentials include tracking information and verifiable credentials. The tracking information includes authorization information. Indeed, in another example, the digital content embedded with a copyright watermark, tracking credentials, and evidence watermarks may alternatively not be packaged together. However, to ensure that the tracking credentials and evidence watermarks of the digital content can be retrieved based on the digital content embedded with the copyright watermark, the tracking credentials and evidence watermarks need to be associated with the digital content embedded with the copyright watermark.

[0144] For digital content obtained through processing by using the method for combining the digital content, copyright information, and tracking credential information, an embodiment of the present application further provides a method for tracking the digital content, which includes: obtaining the digital content; determining, based on the digital content, tracking credential information associated with and bound to the digital content; and tracking the digital content based on the tracking credential information.

[0145] An embodiment of the present application further provides a system for verifying copyright of digital content and tracking digital content. As shown in Figure 7, the system 700 for verifying copyright of digital content and tracking digital content includes: a feature extraction module 701 configured to extract features of the digital content; a detection module 702 configured to compare the extracted features of the digital content with features in the feature database to determine whether the feature database contains features similar to the features of the digital content; a copyright verification module 703 configured to extract copyright information of the digital content and determine ownership of the digital content based on the copyright information; a tracking module 704 configured to extract tracking credentials for the digital content and track the digital content based on the tracking credentials to determine infringing digital content; a processing module 705 configured to take corresponding action against the owner of the infringing digital content and / or remove the digital content from the chain of trust to which the infringing digital content belongs; At least includes.

[0146] For example, after a user uploads digital content, a feature extraction module 701 in the system extracts features of the digital content, e.g., extracts a digital fingerprint of the digital content. Next, a detection module 702 performs a duplication check on the extracted digital fingerprint features, specifically, searches a fingerprint database for fingerprints similar to the extracted fingerprint features, and calculates the similarity between the digital fingerprint features extracted from the digital content and each fingerprint feature stored in the fingerprint database. If a fingerprint feature with a similarity exceeding a certain threshold (e.g., 0.9) is found, the fingerprint database is considered to contain fingerprint features similar to the digital fingerprint features extracted from the digital content, and the fingerprint database is considered to contain the same features as the features extracted from the digital content. If the fingerprint database contains digital fingerprints similar to the digital fingerprints extracted from the digital content, a copyright verification and tracking process is implemented. Specifically, the copyright verification module 703 extracts copyright information from the digital content and determines the ownership of the digital content based on the copyright information. Then, the tracking module 704 extracts tracking credentials from the digital content and tracks the digital content based on the tracking credentials to retrieve the infringing digital content work and all digital content on the chain of trust. The processing module 705 takes action against the owner of the infringing digital content and / or removes the digital content from the chain of trust to which it belongs. If no duplicate digital fingerprints are found, the digital content may be propagated, and another user may be authorized to recreate the propagated digital content through an authorization and chain of trust mechanism. After any digital content in the system is reported by a user, the copyright verification and tracking process is implemented (see FIG. 8).

[0147] See Figure 9 for the copyright verification and tracking process. The claimant (the reporter or content creator who discovered a duplicate during the fingerprint-based duplicate check) determines the original infringing digital content through tracking by using tracking credentials bound to the disputed digital content. The claimant submits a watermark verification key, which allows the system to extract the claimant's copyright watermark from the original infringing digital content. If the extraction is successful, the claimant is the copyright owner. If the extraction fails, the claimant may continue to submit a claim based on the evidence watermark. If the claim is successful, the claimant is the copyright owner. Otherwise, the claim fails. The system takes action against the theft and digital content in the relevant profit chain based on the claim results.

[0148] In one example, the system 700 for verifying copyright of digital content and tracking digital content further includes a digital content generation and upload module 706, in which a user processes the digital content according to the above-described method for processing digital content, embeds a copyright watermark in the digital content, binds the digital content to tracking credentials, performs verification on the processed digital content, and uploads the digital content to the system if the verification is successful.

[0149] FIG. 10 illustrates the generation and uploading of digital content. As shown in FIG. 10, a copyright watermark may be embedded in the digital content based on the aforementioned embedding scheme for digital content. Furthermore, an evidence watermark is obtained from the Copyright Registration Office, and the evidence watermark is combined with the digital content by using the aforementioned dual watermarking scheme for digital content. Tracking information is generated for the digital content. The tracking information may include a digest of the digital content data and may further include a preview of the digital content, a user ID, and other information related to the digital content, such as editing operations and details about the generating device. Links are generated for each entry in the tracking information, and digests are calculated for the entries. These links and digests are then signed as a whole, and the content constitutes a verifiable credential. The tracking information and the verifiable credential are combined into a tracking credential. Finally, the tracking credential and the evidence watermark are attached to the digital content data to form the complete digital content. The user uploads the complete digital content to the system. The system checks whether the content in the tracking credentials is correctly generated and whether the copyright registration office signature in the evidence watermark is correct. The system extracts the digital fingerprint of the digital content data and submits the digital fingerprint to a digital fingerprint database for duplicate checking. If no duplicate fingerprints are found, the digital content can be propagated. Otherwise, the copyright verification and tracking process is implemented.

[0150] In one example, the system 700 for verifying copyright of digital content and tracking digital content further includes an authorization and chain of trust establishment module 707 configured to generate authorization information in response to an authorization request, process the recreated digital content according to the method for processing digital content in an embodiment of the present application to determine second digital content data, and determine third digital content data based on the authorization information and the second digital content.

[0151] As shown in FIG. 11 , a specific implementation process of verifying the copyright of digital content and establishing a digital content authorization and trust chain on a system for tracking digital content is as follows: 1. When user 2 wants to obtain creation authorization for digital content 1 from user 1, user 2 first sends a message to user 1 to request authorization for digital content 1. 2. User 1 generates authorization information AM based on the identification information of both users and information of digital content 1, and then signs the hash value of the authorization information to obtain an authorization signature AS. 3. User 1 sends the authorization information and authorization signature to User 2. 4. User 2 recreates Digital Content 1 to generate Digital Content P2. 5. User 2 embeds a copyright watermark in digital content 2 by using a watermarking method to obtain watermarked content P2*, and obtains evidence watermark S2 from the copyright registration office. For specific implementation, please refer to the description of Figure 3. 6. The tracking credential for digital content 1 is secured to digital content 2. Furthermore, user 2 generates new tracking information 2 based on authorization information including a digital digest of content data P2* for digital content 2, a digital digest of tracking credential 1, authorization credential A, and authorization signature AS, information about user 2, the specific re-creation operation, etc. Next, user 2 generates verifiable credential 2 for tracking information 2. Tracking information 2 and verifiable credential 2 constitute tracking credential 2 for digital content 2. 7. The content P2* embedded with the copyright watermark, tracking credential 1, tracking credential 2, and evidence watermark constitutes the final digital content 2. 8. User 2 submits digital content 2 to the copyright protection system. 9. The system is responsible for review, i.e. (1) Is Tracking Information 2 generated correctly? Is the signature of the credentials and authorization information in Tracking Information 2 correct? (2) Are the digest and overall signatures of verifiable credentials 2 generated correctly? (3) Is the evidential watermark correct? The following will be implemented.

[0152] If all items are correct, the digital content 2 can be officially propagated.

[0153] FIG. 12 illustrates an implementation of copyright verification and tracking for copyright disputes discovered through fingerprint detection. 1. The claimant (digital content creator) creates original digital content data and submits the original digital content data to a system for verifying copyright in digital content and tracking digital content. 2. The system identifies copyright disputes through duplicate checks in the fingerprint database and notifies the complainant of digital content that may be involved in the copyright dispute. 3. If the Complainant believes that the digital content infringes the Complainant's copyright, the Complainant shall report the infringing digital content to the protection system. 4. The system accepts the report and requests the complainant to provide evidence. 5. The complainant submits a verification key, Subkey (which includes two parts, namely, Subkey1 and Subkey2), to be used to generate the corresponding copyright watermark. 6. The system uses the verification key Subkey and the copyright information IC (the copyright information IC may be, for example, the complainant ID) to calculate the watermark extraction key with HASH(IC||Subkey1) and HASH(IC||Subkey2) as follows, and extracts the watermark from the reported digital content. See Figure 4 for the specific watermark extraction process. If the complainant's watermark can be extracted, the complainant owns the copyright, and the system takes action against the owner of the original infringing digital content Media1 and removes all infringing digital content on the chain of trust. If the copyright watermark cannot be extracted, the system analyzes the timestamp T from the evidence watermark S of the data content submitted by the complainant. Then, the system compares the timestamp T with the timestamp T1 in the evidence watermark S1 in the digital content Media1. If T is earlier than T1, the result of the complaint is that the complainant owns the copyright, and the system takes action against the owner of the original infringing digital content Media1 and removes all infringing digital content on the chain of trust. If T is later than T1, the claimant's compliance fails.

[0154] FIG. 13 illustrates an implementation of copyright verification and tracking for copyright disputes arising from user reports. 1. The Complainant determines the first potentially infringing digital content Media1 through tracking based on tracking credentials in the digital content Media2 that may be involved in the dispute and that have been discovered by the Complainant, and reports the digital content to the system. 2. The system requests the claimant to provide evidence. In this case, the claimant provides the system with their verification key, Subkey, based on the watermark scheme. 3. The system calculates the watermark extraction key using the verification key Subkey and the copyright information IC (the copyright information IC may be, for example, the complainant ID) as follows: HASH(IC||Subkey1) and HASH(IC||Subkey2), and extracts the watermark from the reported digital content. See Figure 4 for the specific watermark extraction process. If the complainant's watermark can be extracted, the complainant owns the copyright, and the system takes action against the owner of the original infringing digital content Media1 (this part of the information is included in the tracking information of Tracking Credentials 1) and removes all infringing digital content on the chain of trust. If the copyright watermark cannot be extracted, the system determines that the complainant has failed. Finally, the system sends the complaint result to the complainant. 4. If the Complainant is not satisfied with the outcome, the Complainant files a complaint by submitting the digital content P* bearing the copyright watermark and the evidence watermark S obtained through registration with the Copyright Registration Office. 5. The system verifies whether the evidence watermark S is correct. If the evidence watermark S is correct, the system compares the timestamp T in the evidence watermark S with the timestamp T1 in the evidence watermark S1 in the digital content Media1. If T is earlier than T1, the compliance result is that the claimant owns the copyright, and the system takes action against the owner of the original infringing digital content Media1 (this part of the information is included in the tracking information of Tracking Credentials 1) and removes all infringing digital content on the chain of trust. If T is later than T1, the claimant's compliance fails.

[0155] The system for verifying copyright of digital content and tracking digital content in this embodiment of the present application solves the following problem: media platforms use different DCI numbers, and when digital content is stolen across platforms, copyright cannot be verified. The system can accurately verify copyright across platforms based on the dual guarantee of copyright watermark and evidence watermark, provided that a qualified copyright registration office is used.

[0156] A specific security analysis is as follows: The claimant submits a verification key (Subkey) in the initial claim, and the system attempts to extract a watermark from the disputed digital content. The system extracts the watermark based on the verification key and copyright information (IC). Therefore, based on the legitimacy and security of the watermarking scheme, the system extracts the claimant's watermark if the watermark is not destroyed, in order to verify the copyright. However, if the watermark information is lost due to extensive tampering of the digital content, the system cannot extract the watermark. In this case, the claimant may provide the evidence watermark obtained through the initial registration to the Copyright Registration Office as the basis for the claim. The disputed digital content Media1 also has an evidence watermark. The evidence watermark is generated by the Copyright Registration Office by signing the digital content data and a timestamp using the authority's private key during registration. Therefore, an attacker cannot forge such an evidence watermark without the Copyright Registration Office's private signing key. Therefore, the system may determine users who previously filed copyright claims based on the timestamp information in the evidence watermark. In this way, the copyright verification function is implemented.

[0157] Based on the chain of trust mechanism, the original copyright infringer is accurately determined through tracing, and the entire infringement chain is identified.

[0158] A specific security analysis is as follows: when a claimant discovers infringing digital content Media2, the claimant can quickly learn the initial version of the digital content and all operations performed to modify and propagate the digital content to the current digital content based on the tracking credentials in Media2. Security here is based on the mechanism of an authorized chain of trust. Because all tracking credentials in Media2 contain the relevant information for each digital content on the chain and authorization information, it is difficult for an attacker to spoof any step in the chain. Specifically, as shown in Figure 13, Tracking Information 2 in Tracking Credential 2 contains the digital digest of the digital content data P2* of Media2, so Tracking Information 2 and P2* are bound to each other. Verifiable Credential 2 in Tracking Credential 2 contains the digital digest of each entry in Tracking Information 2 and the user's digital signature on these digests. Therefore, the entire Tracking Credential 2 can be bound to P2* based on Tracking Information 2, and a signature verification algorithm can be used for verification. Furthermore, the evidence watermark also includes a signature obtained by the user by signing a digital digest of the digital content P2* embedded with the watermark. Based on the security of the signature scheme, an attacker cannot forge such a signature. In this way, all parts of the digital content Media2 are bound together based on the signature scheme and the digital digest scheme. Similarly, the data, tracking credentials, and evidence watermark in each digital content are bound together and cannot be tampered with separately. Furthermore, because tracking credentials 2 includes a digital digest of tracking credentials 1 of Media1 and an authorization signature AS obtained by the authorizer by signing authorization credentials AM, a strong authorization-based binding relationship is established between the recreated work Media2 and the original work Media1. Specifically, an attacker cannot forge the original work Media1' of Media2, and an attacker cannot forge the authorization for Media1. In this way, the entire chain of trust is completely bound together, and each step cannot be tampered with.Therefore, based on the chain of trust, the original infringer (the creator of Media1) discovered by the complainant is certainly true. In other words, the original infringer can be reliably determined through tracing.

[0159] The Copyright Registration Office is only responsible for registration and is not involved in copyright verification inquiries, and therefore has a small computational burden.

[0160] The copyright registration office is not involved in the copyright verification process or the tracking process, so the authority only needs to implement the signature during registration, which has a small computational burden.

[0161] Based on the copyright watermark scheme, in most scenarios, the system can still provide copyright evidence for copyright disputes that are not registered with the same copyright registration office to verify copyright.

[0162] Even if the two parties in a dispute are not registered with the same copyright registration office, if one party can extract its own copyright watermark from the other party's digital content based on the accuracy of the copyright watermark scheme, this can indicate that the party is the copyright owner. In this way, the copyright is confirmed.

[0163] An embodiment of the present application further provides a computer device including at least one processor, a memory, and a communication interface, wherein the processor is configured to perform the methods of FIGS.

[0164] FIG. 14 is a diagram of the structure of a computing device according to one embodiment of the present application.

[0165] As shown in FIG. 14, the computer device 1400 includes at least one processor 1401, a memory 1402, and a communication interface 1403. The processor 1401, the memory 1402, and the communication interface 1403 are communicatively connected. The communication connection may be implemented in a wired manner (e.g., using a bus) or a wireless manner. The communication interface 1403 is configured to receive data (e.g., digital content data) transmitted by another device. The memory 1402 stores computer instructions. The processor 1401 executes the computer instructions to implement the method in the aforementioned method embodiments.

[0166] The computer device 1400 may be a device having a computer function, such as a terminal or a server. For example, the terminal may be a personal computer or a smartphone, and the server may be an X86 server.

[0167] The system for verifying copyright of digital content and tracking digital content in an embodiment of the present application is deployed on a computer device 1400 to verify copyright of digital content and track digital content.

[0168] It is to be understood that in this embodiment of the application, processor 1401 may be a central processing unit CPU, or alternatively, processor 901 may be another general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, etc. The general-purpose processor may be a microprocessor, any conventional processor, etc.

[0169] The memory 1402 may include read-only memory and random access memory and may provide instructions and data to the processor 1401. The memory 1402 may further include non-volatile random access memory.

[0170] The memory 1402 may be volatile, nonvolatile, or both. Nonvolatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may be random access memory (RAM), which acts as an external cache. By way of example and not limitation, many forms of RAM may be used, such as static random access memory (static RAM, SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (double data rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchronous link dynamic random access memory (synchlink DRAM, SLDRAM), and direct Rambus random access memory (direct Rambus RAM, DR RAM).

[0171] It should be understood that the computer device 1400 according to this embodiment of the present application can implement and perform the methods shown in Figures 1 to 13 in the embodiments of the present application. For detailed descriptions of the implementation forms of the methods, please refer to the above descriptions. For the sake of brevity, the details will not be described again here.

[0172] One embodiment of the present application provides a computer-readable storage medium, which stores a computer program, the computer instructions of which, when executed by a processor, implement the aforementioned method.

[0173] One embodiment of the present application provides a chip, the chip including at least one processor and an interface, the at least one processor determining program instructions or data by using the interface, the at least one processor configured to execute the program instructions to implement the aforementioned method.

[0174] One embodiment of the present application provides a computer program or computer program product, which comprises instructions that, when executed, enable a computer to perform the above-described method.

[0175] Those skilled in the art may further realize that, in combination with the examples described in the embodiments disclosed herein, the units and algorithm steps may be implemented by electronic hardware, computer software, or a combination thereof. In order to clearly describe the compatibility between hardware and software, the above generally describes the components and steps of the examples based on functions. Whether a function is implemented by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use various methods to implement the functions described for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0176] The steps of a method or algorithm described in the embodiments disclosed herein may be implemented by a processor, or by a combination of hardware and software modules executed by a processor, which may be organized in random access memory (RAM), memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0177] The above specific implementation forms further describe the objectives, technical solutions, and beneficial effects of the present application. It should be understood that the above description is only a specific implementation form of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, or improvement made without departing from the spirit and principle of the present application shall fall within the protection scope of the present application. [Explanation of symbols]

[0178] 700 System for verifying copyright of digital content and tracking digital content 701 Feature Extraction Module 702 Detection Module 703 Copyright Verification Module 704 Tracking Module 705 Processing Module 706 Digital Content Creation and Upload Module 707 Authorization and Chain of Trust Establishment Module 1400 Computer Devices 1401 processor 1402 memory 1403 Communication Interface

Claims

1. 1. A method for processing digital content, comprising: obtaining digital content; performing feature extraction on the digital content to obtain digital content features; generating an intermediate key based at least on the digital content characteristics and the user's secret information; combining at least said intermediate keys to obtain a cryptographic key; embedding a digital content watermark into the digital content based on the encryption key; 1. A method for processing digital content, comprising:

2. the digital content characteristics include a first digital content characteristic and a second digital content characteristic, and the secret information of the user includes first secret information and second secret information; generating an intermediate key based at least on the digital content characteristics and user secret information; deriving a first intermediate key based on the first digital content characteristic and the first secret information, and deriving a second intermediate key based on the second digital content characteristic and the second secret information; Including, said step of at least combining said intermediate keys to obtain an encryption key comprises: combining at least the first intermediate keys to obtain a first encryption key and combining at least the second intermediate keys to obtain a second encryption key. Including, said step of embedding said digital content watermark in said digital content based on said encryption key, determining an embedding position of the watermark in the digital content based on the first encryption key, encrypting the watermark based on the second encryption key, and embedding the encrypted watermark at the embedding position in the digital content; 2. A method for processing digital content according to claim 1, comprising:

3. The method for processing digital content according to claim 2 , wherein the encryption key is further obtained through a binding based on user information.

4. 4. The method of claim 1, further comprising the step of combining the watermark with the embedded digital content into an evidential watermark, the evidential watermark including the copyright information.

5. said step of combining said watermarked digital content with an evidential watermark comprises: performing a digest calculation on the watermarked digital content to determine a first digest; signing the first digest and the copyright information under a private key of the user to determine a first signature; 5. The method of claim 4, comprising:

6. the evidential watermark further includes the first signature, a second signature, and a timestamp; the second signature is obtained by a copyright registration office by signing the first signature, the copyright information, and the timestamp after successful signature verification of the first signature; the timestamp includes information regarding the time at which the copyright registration office completes the second signature; The method of claim 5.

7. 7. The method of claim 5, wherein the first digest is a hash value of the digital content embedded with the watermark.

8. 1. A method for verifying copyright of digital content, comprising: obtaining, by a verifier, an intermediate key; combining, by the verifier, at least the intermediate keys to obtain a cryptographic key; - extracting, by the verifier, the watermark to be verified from the watermarked digital content by using the cryptographic key, the watermarked digital content being obtained through processing by using the method of any one of claims 1 to 8; determining, by the verifier, the ownership of the digital content based on the watermark to be verified; A method for verifying copyright of digital content, including

9. 1. A method for processing digital content, comprising: Obtaining a watermarked digital content, wherein the watermarked digital content is obtained through processing by using a method according to any one of claims 1 to 8; binding tracking credentials to the watermarked digital content, the tracking credentials including tracking information and verifiable credentials, the tracking information including a digest of the digital content and authorization information for the digital content, the verifiable credentials including a signature obtained by signing the digest of the tracking information based on a user's private key; 1. A method for processing digital content, comprising:

10. 10. The method of claim 9, wherein the tracking credentials include a first tracking credential and a second tracking credential, the first tracking credential being generated for a copyright owner of the digital content, the second tracking credential being generated for a grantee of the digital content or for processing the digital content, and the second tracking credential including a digest of the first tracking credential.

11. 11. A computing device comprising a memory and a processor, wherein the memory stores executable code and the processor executes the executable code to perform the method of any one of claims 1 to 10.

12. 11. A computer-readable storage medium storing a computer program that, when executed on a computer, enables the computer to perform the method of any one of claims 1 to 10.

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