A data security transmission method for intelligent manufacturing

Abstract

This invention belongs to the field of image transmission technology, specifically relating to a data security transmission method for intelligent manufacturing. The method includes: obtaining an encrypted result of key information in intelligent manufacturing and a digest of a digital image using the national cryptographic algorithm SM4 and the SM3 hash function; signing the combined result using the SM2 digital signature mechanism to obtain a digital watermark fused with the national cryptographic algorithm signature; extracting secret information from the 5-bit number corresponding to the digital watermark; arranging all pixels in the digital image into a sequence according to the target direction; dividing the sequence into pixel groups of three pixels and pixel pairs of two pixels; embedding two secret information pieces in each pixel group and one secret information piece in each pixel pair using the EMD information hiding algorithm to protect the integrity of the digital image during transmission. This invention achieves higher embedding efficiency while enhancing copyright protection.

Description

Technical Field

[0001] This invention relates to the field of image transmission technology. More specifically, this invention relates to a method for secure data transmission in intelligent manufacturing. Background Technology

[0002] In the field of intelligent manufacturing, the application of digital images is becoming increasingly widespread and crucial. From product design, manufacturing, quality inspection to later maintenance and management, digital images permeate the entire production and operation process. These image data not only carry product appearance information, but also contain a large amount of core information such as technical details, production processes, and quality control standards.

[0003] With the rapid development of information dissemination technology, the copying, dissemination, tampering, theft and leakage of image data have become easy, which has led to numerous copyright and security threats to digital images in smart manufacturing.

[0004] Therefore, effectively protecting the copyright and maintaining the data security of digital images used in intelligent manufacturing has become an important issue for enterprises.

[0005] In smart manufacturing, image data is massive in scale and complex in content, requiring more efficient and robust copyright protection technologies.

[0006] While EMD (Exploiting Modification Direction) information hiding algorithms, as a traditional copyright protection method, can protect image data to a certain extent, their embedding efficiency is low. They can usually only embed one secret message in every two pixel pairs. Such protection strength is difficult to meet the high security requirements of enterprises for large amounts of complex image data. Summary of the Invention

[0007] To address the technical problem of low embedding efficiency in EMD information hiding, which fails to meet the high security requirements of enterprises for large amounts of complex image data, this invention provides a data security transmission method for intelligent manufacturing. The method includes: arranging all pixels in a digital image into a sequence according to a target direction; dividing the sequence into pixel groups of three pixels and pixel pairs of two pixels; embedding two secret information pieces in each pixel group and one secret information piece in each pixel pair using an EMD information hiding algorithm to protect the integrity of the digital image during transmission; the specific operation of the division is: extracting the secret information from the 5-ary number corresponding to the digital watermark; changing the grayscale value of the first three pixels in the sequence by an integer amount within a certain range. If the grayscale value of 3 pixels is changed satisfy and In the EMD information hiding algorithm, the f-value equals the secret information. ,and and In the EMD information hiding algorithm, the f-value equals the secret information. By changing the grayscale values ​​of the first three pixels, two pieces of secret information can be embedded into the pixel group consisting of the first three pixels. Indicates rounding up; otherwise, it modifies the grayscale value of the two pixels in the sequence (the first two pixels) by an integer value within a certain range. The requirement is to determine the grayscale values ​​of two pixels after the change. satisfy and In the EMD information hiding algorithm, the f-value equals the secret information. By changing the grayscale values ​​of two pixels, a secret message can be embedded into the pixel pair.

[0008] This invention adjusts the range of changes in pixel grayscale values ​​from [-1,1] to [-2,2], enabling the embedding of two secret messages within each group of three pixels using the EMD information hiding algorithm by altering the grayscale values ​​of three pixels. Compared to conventional EMD information hiding algorithms, which can only embed one secret message within each pair of two pixels, this invention achieves higher embedding efficiency and enhances copyright protection. In this way, enterprises can more effectively protect their digital image assets, prevent potential infringements, and safeguard their legitimate rights and market competitiveness.

[0009] Preferably, the target direction is any selectable direction.

[0010] Preferably, the target direction is the optional direction with the largest embedding amount.

[0011] This invention selects the option with the largest embedding amount as the target direction, which can embed more secret information in the same image data, significantly improving embedding efficiency. This makes it more difficult to detect and remove unauthorized watermarks, thereby strengthening copyright protection.

[0012] Preferably, the selectable directions include: 0° direction, 45° direction, 90° direction and 135° direction.

[0013] Preferably, the method for obtaining the embedding amount of the optional direction is as follows: according to the optional direction, all pixels in the digital image are grouped into a sequence; the sequence corresponding to the optional direction is divided into pixel groups of 3 pixels and pixel pairs of 2 pixels; the number of all pixel pairs is recorded as... The number of all pixel groups is denoted as Then the embedding amount of the optional direction is equal to .

[0014] This invention calculates the embedding amount for different optional directions by dividing the sequence into pixel groups and pixel pairs. By quantifying the embedding amount for different optional directions, the embedding efficiency can be maximized.

[0015] Preferably, the step of embedding two secret information into the pixel group composed of the first three pixels by changing the gray values ​​of the first three pixels includes: when there are multiple ways to change the gray values ​​of the three pixels, selecting the value with the least impact as the change amount of the gray values ​​of the three pixels, thereby obtaining the changed gray values ​​of the three pixels.

[0016] This invention obtains the grayscale value of 3 pixels after the change by selecting the value with the least impact. In other words, it selects the amount of grayscale value change that has the least impact on the visual effect of the image, which can significantly reduce the degree of image distortion and preserve the visual quality of the image to the greatest extent.

[0017] Preferably, the degree of influence of the value selection method is equal to ; , , These represent the changes in grayscale values ​​of the three pixels within a pixel group under this value selection method. This indicates taking the absolute value.

[0018] Preferably, two grayscale values and The value of f in the EMD information hiding algorithm is: ; This indicates the modulo operation.

[0019] Preferably, after embedding two secret messages into a pixel group consisting of the first three pixels, the first three pixels in the sequence are deleted from the sequence; after embedding one secret message into a pixel pair, the first two pixels in the sequence are deleted from the sequence.

[0020] Preferably, the method further includes: marking the identifier corresponding to a pixel group as 1, marking the identifier corresponding to a pixel pair as 0, and marking the sequence formed by all pixel groups and the identifiers corresponding to pixel pairs in order as an identifier sequence; storing the target direction and the identifier sequence as supplementary information.

[0021] This invention sets and records the identifiers of pixel groups and pixel pairs, enabling accurate and complete extraction of verification information when extracting verification information from the received digital image, thereby ensuring the accuracy of the judgment result on whether the digital image maintains its integrity during transmission.

[0022] The beneficial effects of this invention are as follows:

[0023] This invention embeds two secret messages into every group of three pixels using the EMD information hiding algorithm, achieving higher embedding efficiency while enhancing copyright protection. In this way, enterprises can more effectively protect their digital image assets, prevent potential infringements, and safeguard their legitimate rights and market competitiveness. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating a data security transmission method for intelligent manufacturing according to the present invention;

[0025] Figure 2 This is a schematic diagram illustrating the arrangement order of pixels when all pixels in a digital image are converted into a sequence according to each selectable direction;

[0026] Figure 3 It is a schematic diagram illustrating a digital image;

[0027] Figure 4 This is a schematic diagram illustrating a digital image with an embedded digital watermark. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0030] This invention discloses a data security transmission method for intelligent manufacturing, referring to... Figure 1 This includes steps S1 to S4:

[0031] S1. Acquire digital images used in smart manufacturing.

[0032] In smart manufacturing, digital images are widely and importantly used; from product design to production monitoring and quality inspection, various images contain important copyright information.

[0033] To protect a company's intellectual property and trade secrets, it is necessary to use technologies such as digital watermarking, encryption, access control, and copyright notices to ensure the security of copyright information for these images.

[0034] Specifically, acquiring digital images used in intelligent manufacturing includes, but is not limited to: product design drawings, quality inspection images, production monitoring images, product promotional images, and R&D process images.

[0035] S2. Set the digital watermark after integrating the national cryptographic algorithm signature.

[0036] It should be noted that digital watermarking technology embeds identifying information (i.e., digital watermarks) directly into digital media (including multimedia, documents, etc.) without affecting the original media's usability or making it difficult to detect or modify. However, it can be identified and recognized by the producer. Through this information hidden within the media, it is possible to confirm the content creator, transmit confidential information, or determine whether the media has been tampered with.

[0037] In one embodiment, a binary sequence consisting of 0s and 1s is randomly set as the initial information.

[0038] In another embodiment, the encoding result of key information in intelligent manufacturing is used as the initial information; the encoding method for encoding the key information to obtain the encoding result of the key information includes: ASCII, GB2312, GBK, GB18030, UTF8, ANSI.

[0039] Furthermore, the initial information is encrypted using the national cryptographic algorithm SM4 to ensure its confidentiality; the SM3 hash function is used to generate a digest of the digital image to achieve tamper-proof verification and ensure its integrity; the encrypted result of the initial information and the digest of the digital image are combined to obtain a combined result; the combined result is signed using the SM2 digital signature mechanism, and the obtained result is used as a digital watermark after the signature is fused with the national cryptographic algorithm to realize the sender's identity authentication and non-repudiation functions.

[0040] Among them, the national cryptographic SM4 algorithm, SM3 hash function and SM2 digital signature mechanism are all sensing technologies, which will not be elaborated here.

[0041] It should be noted that digital images in smart manufacturing face numerous copyright and security threats: with the rapid development of information dissemination technology, the copying, dissemination, and tampering of image data have become extremely easy; in the supply chain, images may be illegally used by partners or suppliers, or even stolen by competitors for the development of similar products or technologies; in addition, internal employees may also cause image data leaks due to operational errors or malicious acts; these risks not only harm the economic interests of enterprises, but may also affect the market competitiveness and reputation of enterprises due to the leakage of sensitive information.

[0042] S3. Using the EMD information hiding algorithm, a digital watermark with a signature based on the national cryptographic algorithm is embedded into the digital image to protect the integrity of the digital image during transmission.

[0043] Specifically, the digital watermark, after being fused with the national cryptographic algorithm signature, is embedded into the digital image using the EMD information hiding algorithm. The specific process is as follows:

[0044] 1. Convert the digital watermark to a base-5 number; the secret information is extracted from the base-5 number corresponding to the digital watermark, that is, each digit of the base-5 number corresponding to the digital watermark is taken as a piece of secret information.

[0045] For example, when the digital watermark is “1011010101110101101001”, the corresponding 5-ary number of the digital watermark is “1230114113”, then there are a total of 10 secret information, namely 1, 2, 3, 0, 1, 1, 4, 1, 1, 3.

[0046] 2. Set multiple optional directions to convert all pixels in a digital image into a one-dimensional sequence based on the optional directions.

[0047] In this embodiment, four selectable directions are provided: 0°, 45°, 90° and 135°. In other embodiments, the selectable directions can be set according to the actual application scenario and requirements.

[0048] 3. For any available direction, convert all pixels in the digital image into a one-dimensional sequence according to the available direction.

[0049] When converting all pixels in a digital image into a sequence according to the 0° direction, the arrangement order of the pixels is illustrated in the diagram below. Figure 2 As shown in (a) above, when all pixels in a digital image are converted into a sequence according to the 45° direction, the arrangement order of the pixels is illustrated in the diagram below. Figure 2 As shown in (b) of the diagram, when all pixels in a digital image are converted into a sequence according to the 90° direction, the arrangement order of the pixels is illustrated in the diagram. Figure 2As shown in (c), when all pixels in a digital image are converted into a sequence according to the 135° direction, the arrangement order of the pixels is illustrated in the diagram. Figure 2 As shown in (d) in the figure.

[0050] 4. Divide the sequence into pixel groups of 3 pixels and pixel pairs of 2 pixels: For pixel groups of 3 pixels, two secret messages can be embedded in each pixel group using the EMD information hiding algorithm; for pixel pairs of 2 pixels, one secret message can be embedded in each pixel pair using the EMD information hiding algorithm; the specific division operation is as follows:

[0051] (1) Change the grayscale values ​​of the first 3 pixels in the sequence by an integer amount within a range of 1. .

[0052] (2) If the grayscale value of the 3 pixels is changed satisfy: and In the EMD information hiding algorithm, the f-value equals the secret information. ,and and In the EMD information hiding algorithm, the f-value equals the secret information. By changing the grayscale values ​​of the first three pixels, two pieces of secret information can be embedded into a pixel group consisting of the first three pixels; among them, This indicates rounding up to the nearest integer.

[0053] In the EMD information hiding algorithm, two grayscale values and The f value in the EMD information hiding algorithm is ; This represents the modulo operation; therefore, and The f value in the EMD information hiding algorithm is ; and The f value in the EMD information hiding algorithm is .

[0054] (3) Otherwise, by changing the gray values ​​of the two pixels in the sequence, the first two pixels in the sequence can only embed a secret information into the pixel pair.

[0055] 5. Calculate the embedding amount for the optional directions based on the number of all pixel pairs and the number of all pixel groups. Since only one secret information is embedded in each pixel pair, while two secret information are embedded in each pixel group, the embedding amount for the optional directions is equal to... .

[0056] It should be noted that by quantifying the amount of embedding in different optional directions, the embedding efficiency can be maximized.

[0057] 6. Select a target direction from all available directions.

[0058] In one embodiment, an optional direction is arbitrarily selected from all available directions as the target direction.

[0059] Since the amount of secret information embedded varies when different optional directions are selected as the target direction, the security of the digital image after embedding the digital watermark varies. In order to protect the security of the digital image to the greatest extent, it is necessary to maximize the amount of secret information embedded. Therefore, in another embodiment, the optional direction with the largest amount of embedding is selected as the target direction.

[0060] 7. According to the target direction, all pixels in the digital image are grouped into a sequence and denoted as the target sequence. The target sequence is divided into pixel groups of 3 pixels and pixel pairs of 2 pixels. Using the EMD information hiding algorithm, two secret messages are embedded in each pixel group and one secret message is embedded in each pixel pair to protect the integrity of the digital image during transmission.

[0061] The process of embedding two secret messages in each pixel group is as follows:

[0062] (1) Change the grayscale value of the three pixels that make up the pixel group. The change amount is an integer and the value range is [missing value]. ; Requires the grayscale values ​​after changing 3 pixels. satisfy: and In the EMD information hiding algorithm, the f-value equals the secret information. ,and and In the EMD information hiding algorithm, the f-value equals the secret information. .

[0063] (2) When there are multiple ways to change the grayscale value of 3 pixels, select the one with the least impact as the change in grayscale value of the 3 pixels, and then obtain the changed grayscale value of the 3 pixels; where the impact of the selection method is equal to ; , , These represent the changes in grayscale values ​​of the three pixels within a pixel group under this value selection method. This indicates taking the absolute value.

[0064] It should be noted that choosing the value with the least impact means choosing the grayscale value change that has the least impact on the visual effect of the image. By choosing the grayscale value change that has the least impact on the visual effect of the image, the grayscale values ​​of the three pixels after the change can significantly reduce the degree of image distortion and preserve the visual quality of the image to the greatest extent.

[0065] (3) By changing the grayscale values ​​of the first two pixels, the first secret information can be embedded into the pixel pair formed by the first two pixels; by changing the grayscale values ​​of the first two pixels, the result of rounding up the average grayscale value of the first two pixels can be changed. Meanwhile, by changing the grayscale value of the third pixel, the second secret information can be embedded into... The first three pixels are paired with the third pixel; thus, by changing the grayscale values ​​of the first three pixels, two secret messages can be embedded into the pixel group composed of the first three pixels.

[0066] (4) Remove the first 3 pixels from the sequence; remove the secret information. and delete.

[0067] The process of embedding a secret information into each pixel pair is as follows:

[0068] (1) Change the grayscale values ​​of two pixels by an integer amount within a range of 1. The requirement is to determine the grayscale values ​​of two pixels after the change. satisfy and In the EMD information hiding algorithm, the f-value equals the secret information. .

[0069] (2) By changing the grayscale values ​​of two pixels, a secret information can be embedded into the pixel pair.

[0070] (3) Remove the first two pixels from the sequence; remove the secret information. delete.

[0071] 8. In addition, the identifier corresponding to the pixel group is recorded as 1, and the identifier corresponding to the pixel pair is recorded as 0. The sequence of all pixel groups and the identifiers corresponding to pixel pairs in order is recorded as the identifier sequence. The target direction and the identifier sequence are stored as supplementary information so that all secret information can be accurately extracted during subsequent verification.

[0072] It should be noted that by setting and recording the identifiers of pixel groups and pixel pairs, it is possible to accurately and completely extract verification information when extracting verification information from the received digital image. This makes the judgment on whether the digital image has maintained its integrity during transmission more accurate.

[0073] Furthermore, the EMD information hiding algorithm modifies the grayscale values ​​of two pixels so that the f-value of the modified grayscale values ​​in the EMD information hiding algorithm equals the secret information. This method embeds secret information into a pixel pair composed of two pixels. This allows for the extraction of watermark information from the watermarked image by directly calculating the f-value of the grayscale values ​​of the two pixels in the EMD information hiding algorithm. The specific steps are as follows:

[0074] 1. Calculate the grayscale values ​​of the two pixels in a pixel pair before the change. and f-value in the EMD information hiding algorithm .

[0075] 2. Calculate secret information With grayscale value and f-value in the EMD information hiding algorithm The difference The result of modulo operation with the value 5 .

[0076] 3. Based on the result of the modulo operation To determine the change in grayscale value between the two pixels forming a pixel pair, the specific method is as follows:

[0077] (1) If If the grayscale value of both pixels changes by 0, then the change in grayscale value is 0.

[0078] For example, when secret information When the value is "3", the grayscale value of the first pixel =18, the grayscale value of the second pixel. =20, then the grayscale value and f-value in the EMD information hiding algorithm =3, correspondingly At this point, it is possible to achieve the desired grayscale value without modifying the grayscale values ​​of the two pixels. and f-value in the EMD information hiding algorithm Equivalent to secret information .

[0079] (2) If There are three ways to change the grayscale value of two pixels:

[0080] The first method: the change in grayscale value of the first pixel is 1, and the change in grayscale value of the second pixel is 0.

[0081] For example, when secret information When the value is "3", the grayscale value of the first pixel =17, the grayscale value of the second pixel. =20, then the grayscale value and f-value in the EMD information hiding algorithm =2, correspondingly At this point, simply increasing the grayscale value of the first pixel by 1 will change the grayscale value. and f-value in the EMD information hiding algorithm =3, which equals the secret information. .

[0082] The second method: the change in grayscale value of the first pixel is -2, and the change in grayscale value of the second pixel is -1.

[0083] For example, when secret information When the value is "3", the grayscale value of the first pixel =17, the grayscale value of the second pixel. =20, then the grayscale value and f-value in the EMD information hiding algorithm =2, correspondingly At this point, decreasing the grayscale value of the first pixel by 2 and the grayscale value of the second pixel by 1 will change the grayscale value. and f-value in the EMD information hiding algorithm =3, which equals the secret information. .

[0084] The third type: the change in grayscale value of the first pixel is 0, and the change in grayscale value of the second pixel is -2.

[0085] For example, when secret information When the value is "3", the grayscale value of the first pixel =17, the grayscale value of the second pixel. =20, then the grayscale value and f-value in the EMD information hiding algorithm =2, correspondingly At this point, simply decreasing the grayscale value of the second pixel by 2 will change the grayscale value. and f-value in the EMD information hiding algorithm =3, which equals the secret information. .

[0086] (3) If There are two ways to determine the change in grayscale value between two pixels:

[0087] The first method: the change in grayscale value of the first pixel is 0, and the change in grayscale value of the second pixel is 1.

[0088] For example, when secret information When the value is "3", the grayscale value of the first pixel =18, the grayscale value of the second pixel. =19, then the grayscale value and f-value in the EMD information hiding algorithm =1, correspondingly At this point, simply increasing the grayscale value of the second pixel by 1 will change the grayscale value. and f-value in the EMD information hiding algorithm =3, which equals the secret information. .

[0089] The second method: the change in grayscale value of the first pixel is -1, and the change in grayscale value of the second pixel is -1.

[0090] For example, when secret information When the value is "3", the grayscale value of the first pixel =18, the grayscale value of the second pixel. =19, then the grayscale value and f-value in the EMD information hiding algorithm =1, correspondingly At this point, decreasing the grayscale value of the first pixel by 1, and simultaneously decreasing the grayscale value of the second pixel by 1, will result in a different grayscale value. and f-value in the EMD information hiding algorithm =3, which equals the secret information. .

[0091] (4) If There are two ways to determine the change in grayscale value between two pixels:

[0092] The first method: the change in grayscale value of the first pixel is 0, and the change in grayscale value of the second pixel is -1.

[0093] For example, when secret information When the value is "3", the grayscale value of the first pixel =18, the grayscale value of the second pixel. =21, then the grayscale value and f-value in the EMD information hiding algorithm =0, correspondingly At this point, simply decreasing the grayscale value of the second pixel by 1 will change the grayscale value. and f-value in the EMD information hiding algorithm =3, which equals the secret information. .

[0094] The second method: the grayscale value of the first pixel changes by 1, and the grayscale value of the second pixel changes by 1.

[0095] For example, when secret information When the value is "3", the grayscale value of the first pixel =18, the grayscale value of the second pixel. =21, then the grayscale value and f-value in the EMD information hiding algorithm =0, correspondingly At this point, increasing the grayscale value of the first pixel by 1, and simultaneously increasing the grayscale value of the second pixel by 1, will change the grayscale value. and f-value in the EMD information hiding algorithm =3, which equals the secret information. .

[0096] (5) If There are three ways to change the grayscale value of two pixels:

[0097] The first method: the change in grayscale value of the first pixel is -1, and the change in grayscale value of the second pixel is 0.

[0098] For example, when secret information When the value is "3", the grayscale value of the first pixel =18, the grayscale value of the second pixel. =18, then the grayscale value and f-value in the EMD information hiding algorithm =4, correspondingly At this point, simply decreasing the grayscale value of the first pixel by 1 will change the grayscale value. and f-value in the EMD information hiding algorithm =3, which equals the secret information. .

[0099] The second method: the grayscale value of the first pixel changes by 2, and the grayscale value of the second pixel changes by 1.

[0100] For example, when secret information When the value is "3", the grayscale value of the first pixel =18, the grayscale value of the second pixel. =18, then the grayscale value and f-value in the EMD information hiding algorithm =4, correspondingly At this point, increasing the grayscale value of the first pixel by 2 and simultaneously increasing the grayscale value of the second pixel by 1 will change the grayscale value. and f-value in the EMD information hiding algorithm =3, which equals the secret information. .

[0101] The third type: the change in grayscale value of the first pixel is 0, and the change in grayscale value of the second pixel is 2.

[0102] For example, when secret information When the value is "3", the grayscale value of the first pixel =18, the grayscale value of the second pixel. =18, then the grayscale value and f-value in the EMD information hiding algorithm =4, correspondingly At this point, simply increasing the grayscale value of the second pixel by 2 will change the grayscale value. and f-value in the EMD information hiding algorithm =3, which equals the secret information. .

[0103] For example, for such Figure 3The diagram shows a digital image. Converting all pixels in the digital image into a one-dimensional sequence based on the 0° direction yields the sequence {35,29,31,29,39,41,40,43,37,36,37,37,35,34,32,21}. When the secret information is 1, 2, 3, 0, 1, 1, 4, 1, 1, 3 respectively, the specific partitioning and embedding process is as follows:

[0104] 1. For the first 3 pixels in the sequence, the grayscale values ​​are respectively =35、 =29、 =31, at this point, the secret information =1, secret information =2; Change the grayscale value of the first 3 pixels in the sequence, requiring the change to be an integer and the value to be within the range of 2. When the grayscale values ​​of these three pixels change by 0, -1, and -1 respectively, the resulting grayscale values ​​of the three pixels are as follows: =35、 =28、 =30, at this point and f-value in the EMD information hiding algorithm =1, which is equal to the secret information. ,and and f-value in the EMD information hiding algorithm =2, which is equal to the secret information. Therefore, by changing the grayscale values ​​of the first three pixels, it is possible to embed two secret pieces of information into a pixel group consisting of the first three pixels.

[0105] 2. The first three gray values ​​in the sequence are respectively =35、 =29、 Pixels with a value of 31 are removed from the sequence; secret information is then transferred. =1 and =2 Delete.

[0106] 3. For the first 3 pixels in the sequence, the grayscale values ​​are respectively =29、 =39、 =41, at this point, secret information =3, Secret Information =0; Changes the grayscale value of the first 3 pixels in the sequence, requiring the change to be an integer and within a certain range. The specific method is as follows:

[0107] (1) When the grayscale values ​​of these three pixels change by -2, -1, and 0 respectively, the resulting grayscale values ​​of the three pixels after the change are respectively =27、 =38、 =41, at this time and f-value in the EMD information hiding algorithm =3, which equals the secret information. ,and and f-value in the EMD information hiding algorithm =0, which means equal to the secret information. Therefore, by changing the grayscale values ​​of the first three pixels, it is possible to embed two secret pieces of information into a pixel group consisting of the first three pixels.

[0108] (2) When the changes in the grayscale values ​​of these three pixels are 0, -2, and 0 respectively, the resulting grayscale values ​​of the three pixels after the changes are respectively =29、 =37、 =41, at this time and f-value in the EMD information hiding algorithm =3, which equals the secret information. ,and and f-value in the EMD information hiding algorithm =0, which means equal to the secret information. Therefore, by changing the grayscale values ​​of the first three pixels, it is possible to embed two secret pieces of information into a pixel group consisting of the first three pixels.

[0109] (3) For the first three gray values ​​in the sequence, respectively =29、 =39、 For a pixel with a grayscale value of 41, the change in grayscale value of the three pixels can be determined in two ways. The impact of the first method is equal to... 3. The degree of influence of the second value selection method is equal to 2. Select the value method with the least impact, i.e., the second value method, as the change in grayscale value of the three pixels.

[0110] 4. The first three gray values ​​in the sequence are respectively... =29、 =39、 Pixels with a value of 41 are removed from the sequence; secret information is then transferred. =3 and =0 Delete.

[0111] 5. For the first 3 pixels in the sequence, the grayscale values ​​are respectively =40、 =43、 =37, at this point, the secret message =1, secret information =1; Change the grayscale value of the first 3 pixels in the sequence, requiring the change to be an integer and within the range of 1. When the grayscale values ​​of these three pixels change by 0, 0, and 0 respectively, the resulting grayscale values ​​of the three pixels are as follows: =40、 =43、 =37, at this point and f-value in the EMD information hiding algorithm =1, which is equal to the secret information. ,and and f-value in the EMD information hiding algorithm =1, which is equal to the secret information. Therefore, by changing the grayscale values ​​of the first three pixels, it is possible to embed two secret pieces of information into a pixel group consisting of the first three pixels.

[0112] 6. The first three gray values ​​in the sequence are respectively... =40、 =43、 Pixels with a value of 37 are removed from the sequence; secret information is then transferred. =1 and =1 Delete.

[0113] 7. For the first 3 pixels in the sequence, the grayscale values ​​are respectively =36、 =37、 =37, at this point, the secret message =4, Secret Information =1; Change the grayscale value of the first 3 pixels in the sequence, requiring the change to be an integer and within the range of 1. At this point, no matter how the grayscale values ​​of the first three pixels in the sequence are changed, it is impossible to simultaneously satisfy the following conditions. and In the EMD information hiding algorithm, the f-value equals the secret information. and and In the EMD information hiding algorithm, the f-value equals the secret information. Therefore, only pixel pairs consisting of the first two pixels in the sequence can be modified by changing the grayscale values ​​of the two pixels, with the change amount being an integer and the value range being [value range missing]. When the grayscale values ​​of these two pixels change by -1 and 0 respectively, the resulting grayscale values ​​of the two pixels are respectively =35、 =37, at this point and f-value in the EMD information hiding algorithm =4, which is equal to the secret information. Therefore, by changing the grayscale value of the first two pixels, it is possible to embed a secret message into a pixel pair consisting of the first two pixels.

[0114] 8. The first two gray values ​​in the sequence are respectively... =36、 Pixels with a value of 37 are removed from the sequence; secret information is then transferred. =4 Delete.

[0115] 9. And so on, by assigning grayscale values ​​respectively... =37、 =35、 By changing the grayscale values ​​of three pixels with a grayscale value of 34, and by changing the values ​​by -1, 0, and 1 respectively, it is possible to embed two pieces of secret information into the pixel group consisting of the first three pixels. =32、 By changing the grayscale values ​​of two pixels with a value of 21, and by changing the values ​​by -1 and 0 respectively, a secret message can be embedded into the pixel group consisting of the first two pixels. A schematic diagram of the final digital image with the embedded digital watermark is shown below. Figure 4 As shown.

[0116] S4. Extract verification information from the received digital image, and determine whether the digital image has maintained its integrity during transmission by verifying the consistency between the verification information and the digital watermark.

[0117] The specific process is as follows:

[0118] 1. Based on the target direction in the supplementary information, convert all pixels in the received digital image into a one-dimensional sequence.

[0119] 2. Based on the identifier sequence in the supplementary information, divide the pixels in the sequence into pixel groups of 3 pixels and pixel pairs of 2 pixels: if the identifier is 1, divide the pixels in the sequence into pixel groups of 3 pixels; if the identifier is 0, divide the pixels in the sequence into pixel pairs of 2 pixels.

[0120] 3. Using the EMD information hiding algorithm, extract two secret information from each pixel group, including: calculating the f-value of the grayscale values ​​of the first two pixels in the pixel group in the EMD information hiding algorithm, as the first secret information extracted; calculating the mean of the grayscale values ​​of the first two pixels in the pixel group, and calculating the f-value of the mean of the grayscale values ​​and the grayscale value of the third pixel in the pixel group in the EMD information hiding algorithm, as the second secret information extracted.

[0121] 4. Extract secret information from each pixel pair using the EMD information hiding algorithm, including: calculating the f-value of the grayscale values ​​of the two pixels in the pixel pair in the EMD information hiding algorithm, as the extracted secret information.

[0122] 5. Extract two secret messages from each group of pixels and one secret message from each pair of pixels, and concatenate them in order to form a base-5 number; use the binary number corresponding to this base-5 number as the verification information.

[0123] 6. Perform integrity verification, signature verification, and hash verification on the verification information in sequence to complete the security verification of the transmission channel: If the verification information can pass the integrity verification, signature verification, and hash verification, it means that the current transmission channel is secure, trustworthy, and has not been tampered with, and the channel can continue to be used for subsequent communication; otherwise, it means that the channel has security risks, the communication is no longer trustworthy, and the transmission channel needs to be switched.

[0124] The integrity verification process involves calculating the Hamming distance between the verification information and the digital watermark, and then calculating the ratio of the Hamming distance to the length of the digital watermark. This ratio reflects the consistency between the verification information and the digital watermark, thereby determining whether the digital image maintains its integrity during transmission. If the ratio is greater than the consistency threshold, it indicates that the verification information and the digital watermark have a high degree of consistency, and the verification information passes the integrity verification. If the ratio is less than or equal to the consistency threshold, it indicates that the verification information and the digital watermark have a low degree of consistency, and the verification information fails the integrity verification.

[0125] In addition, signature verification and hash verification are well-known operations in the SM3 hash function and SM2 digital signature mechanism, and will not be elaborated here.

[0126] The specific value of the consistency threshold can be set according to the actual application scenario and requirements, and the range of the consistency threshold is [0.95, 1]. In this invention, the consistency threshold is set to 0.97.

Claims

1. A data security transmission method for intelligent manufacturing, characterized in that, include: According to the target direction, all pixels in the digital image are arranged into a sequence; the sequence is divided into pixel groups of 3 pixels and pixel pairs of 2 pixels. Using the EMD information hiding algorithm, two secret messages are embedded in each pixel group and one secret message is embedded in each pixel pair to protect the integrity of the digital image during transmission. The specific operation of the segmentation is as follows: extract the secret information from the 5-ary number corresponding to the digital watermark, and change the grayscale value of the first 3 pixels in the sequence. The change amount is an integer and the value range is [missing information]. If the grayscale value of 3 pixels is changed satisfy and In the EMD information hiding algorithm, the f-value equals the secret information. ,and and In the EMD information hiding algorithm, the f-value equals the secret information. By changing the grayscale values ​​of the first three pixels, two pieces of secret information can be embedded into the pixel group consisting of the first three pixels. Indicates rounding up; otherwise, it modifies the grayscale value of the two pixels in the sequence (the first two pixels) by an integer value within a certain range. The requirement is to determine the grayscale values ​​of two pixels after the change. satisfy and In the EMD information hiding algorithm, the f-value equals the secret information. By changing the grayscale values ​​of two pixels, a secret message can be embedded into the pixel pair. Two grayscale values and The value of f in the EMD information hiding algorithm is: ; This indicates the modulo operation.

2. The data security transmission method for intelligent manufacturing according to claim 1, characterized in that, The target direction can be any selectable direction.

3. The data security transmission method for intelligent manufacturing according to claim 1, characterized in that, The target direction is the selectable direction with the largest embedding amount.

4. A data security transmission method for intelligent manufacturing according to claim 2 or 3, characterized in that, The selectable directions include: 0°, 45°, 90° and 135°.

5. A data security transmission method for intelligent manufacturing according to claim 3, characterized in that, The method for obtaining the embedding amount of the optional direction is as follows: Organize all pixels in the digital image into a sequence according to an optional direction; The sequence corresponding to the optional direction is divided into pixel groups of 3 pixels and pixel pairs of 2 pixels; the number of all pixel pairs is denoted as... The number of all pixel groups is denoted as ; The embedding amount of the optional direction is equal to .

6. A data security transmission method for intelligent manufacturing according to claim 1, characterized in that, The method of embedding two secret pieces of information into a pixel group consisting of the first three pixels by changing the grayscale values ​​of the first three pixels includes: When there are multiple ways to change the grayscale value of 3 pixels, the method with the least impact is selected as the change in grayscale value of the 3 pixels, and thus the grayscale value of the 3 pixels after the change is obtained.

7. A data security transmission method for intelligent manufacturing according to claim 6, characterized in that, The degree of influence of the value selection method is equal to ; , , These represent the changes in grayscale values ​​of the three pixels within a pixel group under this value selection method. This indicates taking the absolute value.

8. A data security transmission method for intelligent manufacturing according to claim 1, characterized in that, After embedding two secret messages into a pixel group consisting of the first three pixels, the first three pixels in the sequence are deleted from the sequence. After embedding one secret message into a pixel pair, the first two pixels in the sequence are deleted from the sequence.

9. A data security transmission method for intelligent manufacturing according to claim 1, characterized in that, The method further includes: The identifier corresponding to a pixel group is recorded as 1, and the identifier corresponding to a pixel pair is recorded as 0. The sequence formed by all pixel groups and the identifiers corresponding to pixel pairs in order is called the identifier sequence. The target direction and the identifier sequence are stored as supplementary information.

Images