Image copyright protection method for blockchain covert communication

Abstract

The application discloses an image copyright protection method for blockchain covert communication, converts copyright information into RGB values of a plurality of pixel points, adopts a particle swarm optimization algorithm to iteratively generate a writing position of each bit of information, makes an average difference of RGB of all writing positions of pixel points and other eight pixel points around the writing positions minimum, and obtains an optimal embedded pixel position coordinate sequence; feature information of an image file and copyright information thereof are written into the pixel position coordinate sequence, the encrypted information is segmented and embedded into a public key address after being encrypted using a public key address, and the public key is used for transaction, so that the encrypted information is hidden and chained, so that a hidden channel for copyright information transmission is constructed through a blockchain; a copyright holder downloads an image containing copyright information or verifies copyright information of an image, and publishes an image version containing copyright information on social media, so that a problem of partial missing of copyright information is avoided, safety of the copyright information is ensured, and a difficulty of evidence collection when infringement occurs is reduced.

Description

Technical Field

[0001] This invention relates to the fields of blockchain covert communication and image copyright protection technology, and in particular to an image copyright protection method based on blockchain covert communication. Background Technology

[0002] Currently, the importance of digital assets is becoming increasingly prominent, and as an important component of digital assets, image copyright protection is receiving growing attention. Blockchain, with its characteristics of being "unforgeable," "fully traceable," "traceable," "transparent," and "collectively maintained," plays a crucial role in the development of image copyright protection.

[0003] Digital images are characterized by rapid dissemination and difficulty in protecting their rights. After being stolen, digital images are often uploaded and displayed directly without any modification or with only minor alterations. To reduce the difficulty of rights protection, expedite the evidence-gathering process, and strengthen the protection of digital image copyrights, many methods have been developed to add hidden watermarks to images, addressing the issues of easily detectable copyright watermarks or the loss of embedded copyright information due to partial cropping. For example, Chinese Patent Publication No. CN111292219A, entitled "A Method for Implementing Hidden Watermarks on Image Data," proposes a method that uses the four boundary points of a rectangular digital image as positioning points, and then determines the data writing positions based on the pixel or proportional relationship between these positioning points. This processing method is easily recognized by thieves, allowing them to perform batch watermark removal. The data security method disclosed in Chinese patent publication number CN112532613A, entitled "A Covert Communication Method Based on Blockchain Address", transcribs the information to be encrypted into the form of addresses and transaction amounts and then forms blocks, making the transmitted content difficult for third parties to crack. However, this scheme can only embed a small amount of information and is not suitable when the amount of copyright information is large. Summary of the Invention

[0004] The purpose of this invention is to solve the aforementioned problems of existing covert communication of image data, and to provide an image copyright protection method based on blockchain covert communication that embeds a large amount of information, has a more covert channel, and can guarantee the security of copyright information.

[0005] To achieve the above objectives, the technical solution of the image copyright protection method for blockchain covert communication of the present invention includes the following steps:

[0006] Step 1): Generate a write data string based on the copyright holder's original image and personal information, repeat the write data string three times and concatenate them to obtain a repeated write data string; convert the repeated write data string into RGB values ​​of multiple pixels, with each pixel's RGB value being one bit of information;

[0007] Step 2): The particle swarm optimization algorithm is used to iteratively generate the writing position of each bit of information, so that the average difference of the RGB of the pixel at each writing position with the other 8 pixels around it is minimized, and the optimal embedded pixel position coordinate sequence is obtained. The pixel position coordinate sequence is used to embed information into the image and encrypted with public key to obtain encrypted information.

[0008] Step 3): Embed the encrypted information into the public key address in segments, find the address of the largest matching string, and record the address a, the starting position s, the string length l, and the flag information f. Construct a contract from address a to call the transaction.

[0009] Step 4): Submit the length of the encrypted information as a function parameter to the smart contract, and submit the transactions in the order of the transaction queue.

[0010] Further, after step 4), the copyright holder publishes the image on social media. When the original image is found to have been stolen, all transactions in the smart contract are checked first, the contract call transaction is found, the function parameters of the first submission transaction are extracted, and the ciphertext length is obtained; then the remaining transactions are extracted sequentially until the total length of all embedded information fragments equals the ciphertext length; finally, the encrypted information is spliced ​​back together, and the private key is used to decrypt it to obtain the pixel position coordinate sequence of the copyright information written, which is converted into a written data string according to the RGB values ​​to verify the copyright information of the image.

[0011] Further, in step 2), one type of information is written into the scheme as an individual and an individual is randomly generated. The encoding method of individual I is: I = [x1, y1, x2, y2, ... x M y M M represents the total number of bits of information corresponding to the repeatedly written data string, and x represents the total number of bits of information. i y i Let i and y represent the number of pixels in the image where the i-th bit of information is written in the x and y directions, respectively, where i ∈ [1, M] and is a positive integer.

[0012] Furthermore, in step 3), the starting position of the encrypted information is fixed, and the encrypted information is matched with multiple blockchain addresses in turn for maximum string matching. After traversing all addresses, the address containing the maximum matching string is found.

[0013] Furthermore, if the starting position is not at the end of the encrypted information, the starting position of the encrypted information is shifted and then matched with multiple blockchain addresses for the longest string. If the starting position is at the end of the encrypted information, the position information (a, s, l, f) is aggregated according to address a, and the information of the same address is embedded into fragments and aggregated to form the position information sequence pos. Each (s, l, f) in pos is converted into a string of length 3 and used as a function parameter of the transaction. Address a is used as the initiator address of the transaction to construct a contract and call the transaction.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. This invention uses a particle swarm optimization algorithm to iteratively optimize the writing position of each bit of information, so that the average difference between the RGB values ​​of all written pixels and the other 8 surrounding pixels is as small as possible, making it difficult for thieves to remove the digital watermark even if they use image operations such as smoothing and denoising.

[0016] 2. This invention utilizes particle swarm optimization embedding. The randomness inherent in the optimization operation of the writing site during the iteration process makes the digital watermark embedding pattern difficult to identify, preventing attackers from recognizing the watermark pattern and processing watermarks in batches. This makes it difficult for thieves to extract or erase the embedded data on the image even if they analyze and obtain the data processing pattern of the image digital watermark. It avoids the problem of missing copyright information caused by image cropping or the thief overlaying watermarks and stickers on the image.

[0017] 3. This invention has high security, realizing the embedding of features and information citation between blocks and image files, rather than simply embedding image features into newly generated blocks in a one-way manner. That is, even if a third party only obtains one of them, it cannot crack the transmitted data. Furthermore, due to the mutual citation relationship, with the help of the immutability and forgery characteristics of blockchain, it can serve as valid evidence in the event of infringement, reducing the difficulty of obtaining evidence when the infringement is committed.

[0018] 4. This invention does not have the problem of transcribing the information that needs to be encrypted, so it can embed a large amount of information, write more information into copyright information, and make the covert channel more covert, thus ensuring the security of copyright information.

[0019] 5. This invention helps copyright holders bind their original image works to the blockchain, using the covert channels built on the blockchain to store copyright information. By directly extracting features from stolen images and integrating them with information on the blockchain, copyright information can be obtained, reducing the difficulty of obtaining evidence when infringement occurs. Attached Figure Description

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments;

[0021] Figure 1 The flowchart illustrates an image copyright protection method based on blockchain covert communication provided by this invention. Detailed Implementation

[0022] See Figure 1 This invention converts copyright information into RGB values ​​of multiple pixels and uses a particle swarm optimization algorithm to optimize its writing position sequence. It encrypts the pixel position coordinate sequence containing the image file's feature information and its copyright information using a public key address, embedding the encrypted information into segments within the public key address. Transactions are then conducted using these public keys, allowing the encrypted information to be covertly uploaded to the blockchain. This constructs a covert channel for copyright information transmission through the blockchain. Copyright holders can download images containing copyright information or verify the copyright information of images and publish versions of the images containing copyright information on social media.

[0023] Specifically:

[0024] S1: The copyright holder submits the original image to be processed, along with their personal information. A data string is generated based on the original image and personal information. The data string includes, in sequence, the precise time the copyright holder submitted the application, the completion date of the image work, the image work itself, the name of the copyright holder or organization, the copyright holder's ID number or unified social credit code, the date of first publication, and the channel of first publication, separated by semicolons.

[0025] S2: Using a redundancy method similar to that used in QR code generation, the written data string is repeated three times to form a repeated written data string. This is to avoid the problem of missing copyright information caused by image cropping or watermarks and stickers being added to the image by unauthorized users. At this time, the written data string is repeated three times and spliced ​​together to obtain a repeated written data string that is three times the length of the original.

[0026] The repeatedly written data string is then converted to hexadecimal and padded with zeros at the end to ensure its length is a multiple of 6. Starting from the first bit of the repeatedly written data string, the string is accessed sequentially until all bits are traversed. Each 6 bits is stored as the RGB value of a pixel, thus converting it into RGB values ​​for multiple pixels. Each pixel's RGB value is called a bit of information, thereby generating multi-bit information corresponding to the repeatedly written data string.

[0027] S3: The particle swarm optimization algorithm is used to iteratively generate the write position for each bit of information, so that the average RGB difference between the pixel at each write position and its surrounding 8 pixels is minimized as much as possible. Specifically:

[0028] Step 3-1: Treat one information writing scheme as an individual I, randomly generate an individual I, and also generate the writing position for each bit of information. The encoding method of individual I is as follows:

[0029] I = [x1, y1, x2, y2, ... x M y M ],

[0030] Where M is the total number of bits of information corresponding to the repeatedly written data string, and x i y i Let represent the number of pixels in the x and y directions where the i-th bit of information is written on the image. The top left corner is the origin, the positive x-axis direction (vertical direction) is from the top left corner to the bottom left corner, and the positive y-axis direction (horizontal direction) is from the top left corner to the top right corner. Here, i ∈ [1, M] and is a positive integer.

[0031] Step 3-2: Repeat step 3-1 until the number of individuals reaches the population size N, generating N individuals, where N is set to 100. The generated N individuals are then considered as a population.

[0032] Step 3-3: Evaluate each individual in the population and calculate its fitness value. Set the number of evaluation attempts to 1000, and decrease the number of evaluation attempts by one each time an individual is evaluated. The fitness value of each individual in the population is calculated according to the following formula:

[0033]

[0034] Where I represents an individual currently being evaluated, I(1) represents the value of the index1 bit of individual I, f(I) represents the fitness value of individual I, n is the encoding length of individual I, and M is the total number of bits of multi-bit information corresponding to the repeatedly written data string. D(index2,index3) is a convolution function used to calculate the standard deviation of the RGB three-channel color values ​​of all neighboring pixels for the pixel at coordinates (index2,index3) on the image. std(number1,number2,...,number end ) is the standard deviation function, which calculates the standard deviation of the input parameter list (number1, number2, ..., number...). end Calculate the standard deviation. `diff((index4,index5),(index6,index7))` is a color difference calculation function used to calculate the color difference between two pixels with coordinates (index4,index5) and (index6,index7). i ,y i (x) represents the coordinates of the current pixel.i+1 ,y i+1 ), (x i+1 ,y i ), (x i+ 1,y i-1 ), (x i ,y i+1 ), (x i ,y i-1 ), (x i-1 ,y i+1 ), (x i-1 ,y i ), (x i-1 ,y i-1 ) is the same as the current pixel (x) i ,y i The coordinates of the adjacent pixels on the top left, top, top right, left, right, bottom left, bottom, and bottom right sides. R(index8,index9), G(index8,index9), and B(index8,index9) represent the 1st-2nd, 3rd-4th, and 5th-6th bits of the hexadecimal RGB color value of the pixel at coordinates (index8,index9). In the formula, i and j are both index values, ranging from [1,n / 2] and being positive integers. index1 is an index value, ranging from [1,n] and being a positive integer. number1,number2,...,number end The `end` real values ​​are used to refer to the input, where `end` is the number of input parameters and is a positive integer. The seven pairs of parameters (index2, index3), (index4, index5), (index6, index7), (index8, index9), (a, b), (c, d), and (e, f) are coordinate index values, all of which are integers. `index2`, `index4`, `index6`, `index8`, `a`, `c`, and `e` represent the x-axis coordinates of the pixels, while `index3`, `index5`, `index7`, `index9`, `b`, `d`, and `f` represent the y-axis coordinates of the pixels. These x-axis and y-axis coordinates represent the number of pixels in the x and y directions of the image. The top-left corner is the origin, the positive x-axis direction is from the top-left corner to the bottom-left corner, and the positive y-axis direction is from the top-left corner to the top-right corner.

[0035] Steps 3-4: When the number of evaluation attempts is positive, generate the next generation population and return to step 3-3; otherwise, the iteration ends, and the optimal individual is obtained. The optimal embedded pixel position coordinate sequence I is obtained from the encoding method of this optimal individual. best .

[0036] S4: The optimal embedded pixel position coordinate sequence I bestInformation is embedded into the image by writing the MD5 value of the image file, the URL of the image file, the password for obtaining the image file, and copyright information into the pixel position coordinate sequence I. best The encrypted information is obtained by encrypting the information using the public key provided by the copyright holder.

[0037] S5: Fix the starting position k of the encrypted information, match the encrypted information with the maximum string of multiple blockchain addresses held by the copyright holder in turn, embed the segments into the public key address, traverse all addresses, find the address where the maximum matching string is located, and record the address a, starting position s, string length l, and flag information f.

[0038] If k is not at the end of the encrypted information, the starting position of the encrypted information is shifted forward by l positions. A maximum string match is then performed against multiple blockchain addresses held by the copyright holder. After traversing all addresses, the address containing the largest matching string is found, and the address a, starting position s, string length l, and flag information f are recorded. This process is repeated until k is at the end of the encrypted information. If k is at the end of the encrypted information, the recorded position information (a, s, l, f) is aggregated according to address a. Information fragments with the same address are embedded and aggregated to form a position information sequence pos. Each (s, l, f) in pos is converted into a string of length 3 using an ASCII character conversion table. The converted string of pos is used as the function parameter of the transaction. The address a held by the copyright holder is used as the initiator address of the transaction to construct a contract and call the transaction. All transactions are grouped into a transaction queue, awaiting submission to the blockchain for verification. In this way, the encrypted information is embedded in segments into each transaction, and the pixel position coordinate sequence I embedded in each address a is... best Convert it to characters and use it as a function parameter for the contract to call the transaction.

[0039] S6: First, submit the length of the encrypted information as a function parameter to the smart contract as a start signal for communication, and then submit transactions in sequence according to the transaction queue.

[0040] S7: The copyright holder uses an image embedded with copyright information and linked to the blockchain to publish on social media. When the original image is discovered to have been stolen, all transactions in the smart contract are examined, and the contract call transaction initiated by address 'a' is found. The function parameter for the length of the encrypted information from step S6 is extracted to obtain the ciphertext length. Then, the remaining transactions are extracted sequentially until the total length of all embedded information fragments equals the ciphertext length. Finally, the encrypted information is reconstructed and decrypted using the private key to obtain the pixel position coordinate sequence I where the copyright information was written. best The pixel position coordinate sequence I bestIt involves indexing the RGB values ​​of pixels on the stolen image containing embedded copyright information, converting these RGB values ​​into a written data string, and using this written data string to verify the image's copyright information and facilitate evidence collection by the copyright holder regarding infringement. Specifically:

[0041] Step 7-1: The copyright holder views all transactions in the smart contract and finds the transaction initiated by the address held by the copyright holder;

[0042] Step 7-2: Extract the function parameter information of the first transaction submitted in step S6 to obtain the ciphertext length.

[0043] Step 7-3: Extract the remaining transactions initiated by the copyright holders in sequence, reverse the function parameter information to obtain the location information sequence (s, l, f), and then extract the embedded information fragments from the transaction address based on the location information sequence (s, l, f).

[0044] Step 7-4: Calculate the length of each extracted embedded information fragment until the total length of all embedded information fragments equals the length of the ciphertext, indicating that all information extraction is complete. Then, concatenate the embedded information fragments according to the flag information f to obtain the encrypted information.

[0045] Step 7-5: Decrypt the encrypted information using the private key to obtain the MD5 value of the image file, the URL for retrieving the image file, the password for retrieving the image file, and the pixel coordinate sequence I containing the copyright information. best ;

[0046] Steps 7-6: The copyright holder uses the image file to obtain the URL and password to download the image, which is bound to the blockchain and embedded with copyright information. The image bound to the blockchain and embedded with copyright information is used for public release on social media.

[0047] Step 7-7: When the copyright holder discovers that the original image has been stolen, the pixel position coordinate sequence I is written using the copyright information obtained in Step 7-5. best The pixel position coordinate sequence I best The RGB values ​​of pixels are indexed from the stolen image containing copyright information and converted into the repeatable write data string described in step S2.

[0048] Steps 7-8: Set the correction write string to null. For the repeated write data string obtained in Step 7-7, split it into three write data strings of equal length. Traverse the three write data strings one by one from the first character, and each time take the character with the most identical occurrences and write it to the end of the correction write string.

[0049] Steps 7-9: Convert the corrected characters to Unicode encoding. The result includes, in order, the exact time the copyright holder submitted the application, the completion date of the image work, the image work, the name of the copyright holder or organization, the copyright holder's ID number or unified social credit code, the date of first publication, and the channel of first publication, separated by semicolons. This result is used to verify the copyright information of the image and to facilitate the copyright holder in collecting evidence of infringement.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art may make some modifications or alterations to the above-described technical content without departing from the scope of the present invention. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention without departing from the spirit and protection scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for protecting image copyright through blockchain-based covert communication, characterized by: Includes the following steps: Step 1): Generate a write data string based on the copyright holder's original image and personal information, repeat the write data string three times and concatenate them to obtain a repeated write data string; convert the repeated write data string into the RGB values ​​of multiple pixels, with each pixel's RGB value being one bit of information; Step 2): The particle swarm optimization algorithm is used to iteratively generate the writing position of each bit of information, so that the average difference of the RGB of the pixel at each writing position and the other 8 pixels around it is minimized, and the optimal embedded pixel position coordinate sequence is obtained. The pixel position coordinate sequence is used to embed information into the image and encrypted with public key to obtain encrypted information. Step 3): Embed the encrypted information into the public key address in segments, find the address of the largest matching string, and record the address a, the starting position s, the string length l, and the flag information f. Construct a contract from address a to call the transaction. The starting position of the encrypted information is fixed, and the encrypted information is matched with multiple blockchain addresses in turn to find the address where the maximum matching string is located after traversing all addresses. If the starting position is not at the end of the encrypted information, the starting position of the encrypted information is shifted and then matched with the longest string of multiple blockchain addresses in turn; if the starting position is at the end of the encrypted information, the position information (a, s, l, f) is aggregated according to address a, the information of the same address is embedded into fragments and aggregated to form the position information sequence pos, each (s, l, f) in pos is converted into a string of length 3 and used as the function parameter of the transaction, and address a is used as the initiator address of the transaction to construct the contract and call the transaction; Step 4): Submit the length of the encrypted information as a function parameter to the smart contract, and submit the transactions in the order of the transaction queue.

2. The image copyright protection method for blockchain covert communication according to claim 1, characterized in that: After step 4), the copyright holder publishes the image on social media. When the original image is found to have been stolen, all transactions in the smart contract are checked first. The contract call transaction is found, and the function parameters of the first submission transaction are extracted to obtain the ciphertext length. Then, the remaining transactions are extracted sequentially until the total length of all embedded information fragments equals the ciphertext length. Finally, the encrypted information is spliced ​​back together and decrypted using the private key to obtain the pixel position coordinate sequence of the copyright information. The RGB values ​​are then converted into a written data string to verify the copyright information of the image.

3. The image copyright protection method for blockchain covert communication according to claim 2, characterized in that: After extracting the remaining transactions in sequence, the location information sequence (s, l, f) is obtained by reverse reconstruction based on the extracted function parameter information. Then, the embedded information fragments are extracted from the transaction address based on the location information sequence (s, l, f). The length of each embedded information fragment is calculated until the total length of all embedded information fragments equals the length of the ciphertext.

4. The image copyright protection method for blockchain covert communication according to claim 2, characterized in that: Based on the flag information f, the embedded information fragments are concatenated to restore the encrypted information.

5. The image copyright protection method for blockchain covert communication according to claim 2, characterized in that: Copyright holders use image files to obtain URLs and passwords to download images containing embedded copyright information, which they then publicly release on social media.

6. The image copyright protection method for blockchain covert communication according to claim 2, characterized in that: For repeated write data strings, split them into three write data strings of the same length according to their length. Traverse the three write data strings one by one from the first character to the next, and take the character with the most identical characters each time and write it to the end of the correction write character.

7. The image copyright protection method for blockchain covert communication according to claim 1, characterized in that: In step 2), one type of information is written into the scheme as an individual and an individual is randomly generated. The individual encoding method is as follows: M is the total number of bits of information corresponding to the repeatedly written data string, and x i y i Let i and y represent the number of pixels in the image where the i-th bit of information is written in the x and y directions, respectively, where i ∈ [1, M] and is a positive integer.

8. The image copyright protection method for blockchain covert communication according to claim 1, characterized in that: In step 2), the MD5 value of the image file, the URL for obtaining the image file, the password for obtaining the image file, and the copyright information are written into the pixel position coordinate sequence.

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