A data ownership revocation method based on incremental digital watermarking

Abstract

The present application relates to a kind of data ownership revocation methods based on incremental digital watermarking.The present application method includes the following steps:1) the initialization of the public parameters involved in the ownership revocation process;2) cloud server removes the revoked user from the image cloud data owner list;3) cloud server embeds incremental digital watermarking into the image cloud data and synchronizes the incremental digital watermarking to the existing valid image cloud data owner;4) cloud server updates the data ownership proof tag in cooperation with any online and valid image cloud data owner.The present application addresses the need for complete management of image cloud data ownership, complements the existing image cloud data ownership proof method, while taking into account the performance of cloud storage services, solves the problem of image cloud data ownership revocation.

Description

Technical Field

[0001] This invention belongs to the field of cloud service security attribute technology, and in particular relates to a method for revoking data ownership based on incremental digital watermarking. Background Technology

[0002] With the continuous development of cloud computing technology, efficient, convenient, and cost-effective cloud storage services have been widely adopted in practice. Large amounts of data, including images, are hosted in the cloud, allowing users to connect to and manage their data resources simply through the network. In this online service model, due to the loss of physical control over the data, users are increasingly concerned about the security of their data in the cloud. The confirmation of ownership of cloud data is of paramount importance to users, as it concerns the attribution of data elements and the enormous economic value they represent. This is a crucial foundation for the sustainable development of the cloud service market and the data element market.

[0003] Currently, some research has been conducted on cloud data ownership verification, with data ownership proof based on data integrity status verification being one of the most important technical means. When multiple users simultaneously possess the same data, the cloud server confirms ownership by checking the integrity of the data held by each user. Meanwhile, to prevent the loss of digital rights due to cloud servers directly accessing plaintext, encrypted data has gradually become the foundation for data ownership verification. However, cloud data is highly heterogeneous, with small volumes of text data and metadata coexisting with large volumes of multimedia data. The performance degradation caused by high-security encryption on large volumes of data directly conflicts with the real-time efficiency of cloud storage services. Furthermore, complex encryption operations cause a significant loss of plaintext characteristics in multimedia cloud data, greatly reducing its usability and circulation.

[0004] To address this issue, researchers have proposed a digital watermarking-based ownership proof method (DEduplication watermarking, DEW) for image cloud data ownership verification. Taking image cloud data as the starting point, this method balances the needs for ownership verification and availability requirements. It combines Message-Locked Encryption (MLE) and a random factor to design a digital watermark that can be asynchronously shared among multiple data owners. The digital watermark replaces encryption to protect the ownership of image cloud data by multiple users. Simultaneously, the cloud server verifies the integrity of the data held by a user by checking their submitted commitment based on the original image data, thus achieving effective management of cloud data ownership. However, this method neglects the validity period of cloud data ownership, focusing only on confirming ownership during the access period and providing passive protection during the duration of ownership, without handling the revocation or cancellation of ownership. Currently, the effective revocation of image cloud data ownership has not received sufficient attention or a satisfactory solution.

[0005] For the convenience of describing this invention application, some related technologies will be introduced below.

[0006] (1) Proof of data ownership:

[0007] Proof of Ownership (PoW) is a two-party interactive proof process involving a commitment, challenge, and response. Based on the verification of the integrity of the data held by the proving party, the verifier determines whether the proving party is the rightful owner of the data. When PoW is applied to cloud storage services, the cloud server acts as the verifier, while the user acts as the proving party. PoW is a crucial technological foundation for establishing cloud data ownership.

[0008] Based on the data type being processed, ownership proofs can be categorized into three types: those for general plaintext data, those for encrypted data, and those for multimedia data. Ownership proofs for general plaintext data operate under the assumption of complete trust in the cloud server, making them unsuitable for real-world production. Ownership proofs for encrypted data introduce various encryption algorithms to prevent direct data loss through highly secure encryption, but this significantly hinders system performance and cloud data availability. Ownership proofs for multimedia data seek a balance between data ownership protection and system performance / multimedia data availability, using digital watermarking instead of encryption to provide a generally secure yet highly efficient ownership protection solution.

[0009] (2) Digital watermarking:

[0010] Digital watermarking is a technology that utilizes the sparsity of multimedia data to add specific noise to the carrier data according to user needs, thereby achieving digital rights protection. Digital watermarking has almost no impact on the usability and circulation of the original multimedia data. Based on the signal domain into which the digital watermark is embedded, digital watermarking can be divided into spatial domain digital watermarking and frequency domain digital watermarking. Spatial domain digital watermarking directly superimposes the noise signal representing digital rights onto the spatial domain of the multimedia data; frequency domain digital watermarking first transforms the multimedia data from the spatial domain to the frequency domain (such as discrete Fourier transform), then embeds the noise signal representing digital rights, and finally restores the multimedia data from the frequency domain back to the spatial domain through methods such as inverse Fourier transform. Frequency domain digital watermarking is more robust than spatial domain digital watermarking and is more effective in resisting attacks such as alteration, cutting, compression, and rotation. Digital watermarking can also be divided into blind watermarking and non-blind watermarking based on whether the original data is required for watermark extraction calculations, or into robust watermarking and fragile watermarking based on the robustness of the digital watermark. Summary of the Invention

[0011] The purpose of this invention is to provide a data ownership revocation method based on incremental digital watermarking to address the need for complete ownership confirmation of image cloud data, thus solving the problem of image cloud data ownership revocation that has not been considered in the above-mentioned image cloud data ownership proof.

[0012] To achieve the above objectives, the technical solution of the present invention is: a method for revoking data ownership based on incremental digital watermarking, comprising the following steps:

[0013] (1) The cloud server S globally publishes the public parameters required for the revocation of ownership of image cloud data, including q and F. q A secure cryptographic hash function H with message digest length v, l, and v. v (·), where q is a large prime number whose length satisfies the communication security requirements, and F q It is a finite field containing q elements, with generator g, and l is the length of the digital watermark that meets security requirements; for image cloud data f associated with multiple owners, cloud server S uses the owner list L owner Manage ownership of image cloud data f by multiple users;

[0014] (2) If the owner O is revoked from the image cloud data f t The ownership of this file will be transferred to the cloud server S. t From the owner list L owner Delete;

[0015] (3) Cloud server S performs 256-bit grayscale standardization on the image pixels and divides the standardized image matrix into N = n × s segments, i.e., pixels, where n is the number of data blocks, each data block contains s data segments, and the value space of the data segments is consistent with the value space of the standardized pixels.

[0016] (4) If this round is the first revocation of ownership, proceed to step (5); if this round is not the first revocation of ownership, record the image data as f. # Cloud server S from f # The process of removing the previous incremental watermark to obtain image cloud data f includes the following steps:

[0017] (4-1) Cloud server S uses the random seed that was used in the previous round and saved locally. # Input a pseudo-random number generator, perform a modulo-N operation on the output random numbers to obtain a global index of the image data, and then perform modulo-n and modulo-s operations on each index value to obtain a set of image data coordinates. in It is the selected i-th # The row coordinates of each pixel It is the selected i-th # The column coordinates of each pixel;

[0018] (4-2) Cloud server S sequentially generates a randomly generated digital watermark (abbreviated as wm) bit string of length l as b. # wm The i-th # Bit information With binary The i-th # The standard values ​​of the pixels pointed to by each element are subjected to a bitwise XOR operation to restore the image cloud data f;

[0019] (4-3) Delete seed on cloud server S # and b # wm ;

[0020] (5) The cloud server S embeds an incremental digital watermark into the image cloud data f and synchronizes it with the existing valid image cloud data f, including the following steps:

[0021] (5-1) Cloud server S selects a random seed and inputs it into a pseudo-random number generator. It then performs a modulo-N operation on the output random numbers to obtain a global index of the image data. Finally, it performs modulo-n and modulo-s operations on each index value to obtain a set of image data coordinates { <x i ,y i >|1≤i≤l}, where x i The row coordinate of the selected i-th pixel is y. i It is the column coordinate of the selected i-th pixel;

[0022] (5-2) Cloud server S inputs a true random seed into a pseudo-random number generator and obtains a random bit string b of length l. wm ;

[0023] (5-3) Cloud server S sequentially sends b wm The i-th bit information b wm_i With the pair { <x i ,y i The standard value of the pixel pointed to by the i-th element in the expression >|1≤i≤l} is subjected to a bitwise XOR operation to obtain f';

[0024] (5-4) Cloud server S transmits { via a secure channel <x i ,y i >|1≤i≤l} and b wm Synchronize with L owner The legal owners of f' currently existing in the list;

[0025] (5-5) Cloud server S locally stores f', seed and b wm Delete image cloud data f;

[0026] (6) Cloud server S and any online and valid owner O of f' a Collaboratively updating the data integrity certificate label includes the following steps:

[0027] (6-1) Cloud server S from F q Randomly select a new set of private integrity proof coefficients {α} j '∈F q |1≤j≤s}, and calculate σ for each data block. i '=α j 'm' ij , where m' ij This refers to the j-th segment of the i-th data block of f'. The {α} involved in this step... j '∈F q |1≤j≤s}、{σ i '|1≤i≤n} are all F q Elements on;

[0028] (6-2) Cloud server S will {σ i ',α' j |1≤i≤n,1≤j≤s} are sent to O a ;

[0029] (6-3)O a Calculate the new integrity proof label Where I wm It is a random bit string of a basic digital watermark embedded by the owner, w i It is the set of column coordinates of the pixels in the i-th row that should have a digital watermark embedded and whose embedded bit information is "1". "||" is a concatenation operation. For F q Elements on;

[0030] (6-4)O a Will Send to cloud server S;

[0031] (7) Cloud server S usage Replace the original integrity proof tag {σ i The public integrity proof coefficients are updated to |1≤i≤n}. This step involves and All are F q The elements on.

[0032] In one embodiment of the present invention, the basic digital watermark in the image cloud data f stored on the cloud server is embedded by the owner O1 of the first uploaded image cloud data f, including the following steps:

[0033] (1) O1 will transfer the original image data f * Perform 256-bit grayscale normalization, and divide the normalized pixel matrix into N = n × s segments, where n is the number of data blocks and each data block contains s data segments;

[0034] (2) O1 uses the Secure Message Locking Encryption MLE algorithm to derive a random seed. * and seed * Input a random number generator, and perform a modulo-N operation on the output set of non-repeating random numbers to obtain the global index of the pixel. Then, perform modulo-n and modulo-s operations on each index to obtain a set of pixel coordinates. <x i* ,y i* >|1≤i*≤l}, where x i* It is the selected i-th * The row coordinates of the pixel, y i* It is the selected i-th * The column coordinates of each pixel;

[0035] (3) O1 inputs a true random seed, including hardware signals, into the pseudo-random number generator to obtain a random bit string I of length l. wm ;

[0036] (4) O1 will sequentially put I wm i-th * Bits With binary The i-th * Perform a bitwise XOR operation on the pixel values ​​pointed to by each element to obtain the image cloud data f.

[0037] In one embodiment of the present invention, in step (7), the integrity label and integrity proof coefficient originally held by the cloud server S are initialized by O1, the owner of the first uploaded image cloud data f, that is, O1 randomly selects a set of private integrity proof coefficients {α}. j ∈F q |1≤j≤s}, and calculate the public integrity proof coefficient. and the integrity label for each data block Where m ij It is the j-th segment of data within the i-th data block of f, where I wm It is a random bit string of the underlying watermark embedded in O1. This step involves {α} j ∈F q |1≤j≤s}、 and σ i All are F q The elements on.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] This invention solves the problem of effectively revoking ownership of image cloud data, complementing existing image cloud data ownership proof methods and enabling comprehensive management of image cloud data ownership. This invention utilizes the sparsity and superpositionability of digital watermarks, with the cloud server performing incremental updates to the digital watermarks, thereby revoking the ability of the revoked owner to restore the original image cloud data. Secondly, in this method, the cloud server and the trusted data owner collaborate to update the data ownership proof label, transferring most of the computational burden during the update process from the user to the more resource-rich cloud, achieving reasonable computational load balancing, and also stripping the revoked owner of their ability to prove data ownership. Attached Figure Description

[0040] Figure 1 This is a flowchart of the incremental digital watermark update process in the method of the present invention.

[0041] Figure 2 This is a flowchart of the data ownership tag update process in the method of the present invention. Detailed Implementation

[0042] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0043] like Figure 1 , 2 As shown, the present invention provides a method for revoking ownership of image cloud data based on incremental digital watermarking, comprising the following steps:

[0044] (1) The cloud server S globally publishes the public parameters required for the revocation of ownership of image cloud data, including q and F. q A secure cryptographic hash function H with message digest length v, l, and v. v (·), where n and q are two large prime numbers whose lengths satisfy the communication security requirements, F q S is a finite field containing q elements, with generator g, and l is the length of the digital watermark that meets security requirements. For image cloud data f associated with multiple owners, S uses the owner list L. owner Managing ownership of f by multiple users. In this step and the following, f specifically refers to the basic digital watermark embedded by O1, the first owner to upload f, and includes the following steps:

[0045] (1-1)O1 will use the original image data f * Perform 256-bit grayscale normalization, and divide the normalized pixel matrix into N = n × s segments, where n is the number of data blocks and each data block contains s data segments;

[0046] (1-2) O1 uses the Secure Message Lock Encryption (MLE) algorithm to derive a random seed. * and seed * Input a random number generator, and perform a modulo-N operation on the output set of non-repeating random numbers to obtain the global index of the pixel. Then, perform modulo-n and modulo-s operations on each index to obtain a set of pixel coordinates. <x i* ,y i* >|1≤i*≤l}, where x i* It is the selected i-th * The row coordinates of the pixel, y i* It is the selected i-th * The column coordinates of each pixel;

[0047] (1-3) O1 inputs a hardware signal, such as a true random seed, into the pseudo-random number generator to obtain a random bit string I of length l. wm ;

[0048] (1-4)O1 will sequentially place I wm i-th * Bit (denoted as) ) and binary The i-th * Perform a bitwise XOR operation on the pixel values ​​pointed to by each element to obtain f;

[0049] (2) If the owner O is removed from f t S will retain ownership of the file from O. t From the owner list L owner Delete;

[0050] (3) S standardizes the image pixels to 256-bit grayscale and divides the standardized image matrix into N = n × s segments, where n is the number of data blocks and each data block contains s data segments.

[0051] (4) If this round is the first revocation of ownership, proceed to step (5); if this round is not the first revocation of ownership, record the image data as f. # S from f # The process of removing the previous incremental watermark to obtain f involves the following steps:

[0052] (4-1)S uses the random seed that was used in the previous round and is saved locally. # Input a pseudo-random number generator, perform a modulo-N operation on the output random numbers to obtain a global index of the image data, and then perform modulo-n and modulo-s operations on each index value to obtain a set of image data coordinates. in It is the selected i-th #The row coordinates of each pixel It is the selected i-th # The column coordinates of each pixel;

[0053] (4-2) S sequentially generates a randomized digital watermark (abbreviated as wm) bit string of length l, b. # wm The i-th # Bit information (denoted as) ) and binary The i-th # Perform a bitwise XOR operation on the standard value of the pixel pointed to by each element to restore f;

[0054] (4-3)S Delete seed # and b # wn ;

[0055] (5) S embeds an incremental digital watermark into f and synchronizes it with the existing valid owners of f, including the following steps:

[0056] (5-1) S selects a random seed and inputs it into the pseudo-random number generator. The output random numbers are then processed modulo N to obtain a global index of the image data. Finally, modulo n and s operations are performed on each index value to obtain a set of image data coordinates { <x i ,y i >|1≤i≤l}, where x i The row coordinate of the selected i-th pixel is y. i It is the column coordinate of the selected i-th pixel;

[0057] (5-2) S inputs a true random seed into the pseudo-random number generator, resulting in a random bit string b of length l. wm ;

[0058] (5-3)S will place b in order wm The i-th bit of information (denoted as b) wm_i ) and binary { <x i ,y i The standard value of the pixel pointed to by the i-th element in the expression >|1≤i≤l} is subjected to a bitwise XOR operation to obtain f';

[0059] (5-4)S transmits { via a secure channel <x i ,y i >|1≤i≤l} and b wm Synchronize with L owner The legal owners of f' currently existing in the list;

[0060] (5-5)S Locally save f', seed and b wmDelete f;

[0061] (6) S and any online and valid owner of f' O a Collaboratively updating the data integrity certificate label includes the following steps:

[0062] (6-1)S randomly selects a new set of integrity proof coefficients {α} j '∈F q |1≤j≤s}, and calculate σ for each data block. i '=α j 'm' ij , where m' ij This refers to the j-th segment of the i-th data block of f'. The {α} involved in this step... j '∈F q |1≤j≤s} and {σ} i '|1≤i≤n} are all F q Elements on;

[0063] (6-2)S will {σ i ',α' j |1≤i≤n,1≤j≤s} are sent to O a ;

[0064] (6-3)O a calculate Where I wm It is a random bit string of basic watermark embedded by the owner, w i This is the set of column coordinates of the pixels in the i-th row that should have a digital watermark embedded and whose embedded bit information is "1". "||" is a concatenation operation. This step involves... For F q Elements on;

[0065] (6-4)O a Will Send to S;

[0066] (7) S uses Replace the original integrity proof tag {σ i The public integrity proof coefficients are updated to |1≤i≤n}. in {σ i |1≤i≤n} and All are F q The elements on the f. The integrity label and integrity proof coefficient are initialized by O1, the owner of the first uploader f, that is, O1 randomly selects a set of private integrity proof coefficients {α}. j ∈F q |1≤j≤s}, and calculate the coefficient of the common complete new proof. and the integrity label for each data block Where m ij It is the j-th segment of data within the i-th data block of f, where I wm It is a basic watermark random bit string embedded by O1, {α j ∈F q |1≤j≤s}、 and σ i All are F q The elements on.

[0067] The above are preferred embodiments of the present invention. Any changes made to the technical solution of the present invention that do not exceed the scope of the technical solution of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for revoking data ownership based on incremental digital watermarking, characterized in that, Includes the following steps: (1) Cloud server The publicly available parameters required for the revocation of ownership of image cloud data are published globally. These publicly available parameters include... , , and a message digest length of Secure cryptographic hash function ,in It is a large prime number whose length meets the requirements of communication security. It includes A finite field of n elements whose generator is , It is the length of the digital watermark that meets security requirements; Image cloud data associated with multiple owners cloud server Use owner list Managing multi-user image cloud data Ownership; (2) If from image cloud data Owner O was removed t Image cloud data Ownership of cloud servers Will From the list of owners Delete; (3) Cloud server The image pixels are standardized to 256-bit grayscale, and the standardized image matrix is ​​divided into... Each segment is a pixel, among which It refers to the number of data blocks, and each data block contains... Each data segment has a value space that is consistent with the value space of the standardized pixels. (4) If this round is the first revocation of ownership, then proceed to step (5) for execution; If ownership is revoked in this round (not the first time), the image data will be recorded as... cloud server from Remove the previous incremental watermark to obtain image cloud data. This includes the following steps: (4-1) Cloud Server Using the random seed used in the previous round and saved locally Input a pseudo-random number generator, and perform a modulo operation on the output random numbers. The operation yields a global index of a set of image data, and then modulo operations are performed on each index value. and model The operation yields a set of image data coordinates. ,in The selected number The row coordinates of each pixel The selected number The column coordinates of each pixel; (4-2) Cloud Server Randomly generated lengths are arranged in order. Digital watermark bit string The Bit information With binary The Middle The standard values ​​of the pixels pointed to by each element are subjected to a bitwise XOR operation to restore the image cloud data. ; (4-3) Cloud Server delete and ; (5) Cloud server Image cloud data Incremental digital watermarking is embedded in the existing valid image cloud data. To synchronize with the owner, the following steps are required: (5-1) Cloud Server Select a random seed Input a pseudo-random number generator, and perform a modulo operation on the output random numbers. The operation yields a global index of a set of image data, and then modulo operations are performed on each index value. and model The operation yields a set of image data coordinates. ,in The selected number The row coordinates of each pixel The selected number The column coordinates of each pixel; (5-2) Cloud Server Inputting a true random seed into a pseudo-random number generator yields a seed of length [length missing]. random bit string ; (5-3) Cloud Server In order The Bit information With binary The Middle Perform a bitwise XOR operation on the standard value of the pixel pointed to by each element to obtain... ; (5-4) Cloud Server via secure channel and Synchronize Existing in the list The rightful owner; (5-5) Cloud Server Local save , and Delete image cloud data ; (6) Cloud server With any online and valid Owner Collaboratively updating the data integrity certificate label includes the following steps: (6-1) Cloud Server from Randomly select a new set of private integrity proof coefficients { }, and calculate for each data block. ,in for The The first data block Segment data; { }、{ All of them are Elements on; (6-2) Cloud Server Will{ }Sent to O a ; (6-3) Calculate the new integrity proof label ( || ),in It is a random bit string of a basic digital watermark embedded by the owner. It is the first The row contains the set of column coordinates of pixels that should have a digital watermark embedded and whose embedded bit information is "1". "||" is a concatenation operation. for Elements on; (6-4) Will Send to cloud server ; (7) Cloud server use Replace the original integrity certificate label The public integrity proof coefficient is updated to ; and All The elements on.

2. The data ownership revocation method based on incremental digital watermarking according to claim 1, characterized in that, Image cloud data stored on cloud servers The basic digital watermarking in the image was first uploaded to the cloud data. Owner Embedding includes the following steps: (1) Original image data Perform 256-bit grayscale normalization, and divide the normalized pixel matrix into... Each segment, among which It refers to the number of data blocks, and each data block contains... One data segment; (2) Use the Secure Message Lock Encryption MLE algorithm to derive a random seed. and will Input a random number generator, and output a set of non-repeating random numbers to perform a modulo operation. The operation yields the global index of the pixel, and then modulo operation is performed on each index. and model The operation yields a set of pixel coordinates. ,in The selected number The row coordinates of each pixel The selected number The column coordinates of each pixel; (3) Inputting a true random seed, including hardware signals, into a pseudo-random number generator yields a string of length [length missing]. random bit string ; (4) Will be in order No. Bits With binary The Middle Perform a bitwise XOR operation on the pixel values ​​pointed to by each element to obtain the image cloud data. .

3. The data ownership revocation method based on incremental digital watermarking according to claim 1, characterized in that, In step (7), the cloud server The original integrity label and integrity proof coefficient were obtained from the first uploaded image cloud data. Owner Initialization complete, i.e. Randomly select a set of private integrity proof coefficients { } and calculate the public integrity proof coefficient. and the integrity label for each data block ,in yes The Within the data block, the first Segment data, among which It is by Embedded basic watermark random bit string; { }、 and All The elements on.

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