Electronic file printing anti-counterfeiting and identification method and system based on virtual printing

Abstract

The invention provides an electronic file printing anti-counterfeiting and identification method and system based on virtual printing, and the method comprises the steps: data coding and preprocessing: calculating an electronic file Hash value of an original electronic signature, storing the electronic file Hash value in a digital signature library, carrying out the Hash extension, and carrying out the interleaving arrangement of the coded data according to bits; steganography and embedding: dividing a printing page into grids, selecting a text edge or a background area as an embedding point, finely adjusting a printing voltage, and regulating and controlling a normal printing ink amount and an ink shortage state; anti-interference printing: repeatedly embedding the same data in the four corners and the central area of the document, and performing multiple copying; printing a special ink-deficient pattern on the edge of the document for positioning and marking; and extracting and verifying data. The invisible anti-counterfeiting mark is embedded in the printing process of the electronic file with the electronic signature through the printing steganography technology based on nozzle voltage / heating pulse control, the consistency of the content of the paper file and the content of the electronic file with the electronic signature is ensured, and meanwhile the authenticity of the paper file and the authenticity of signatures and signature pictures can be rapidly identified.

Description

Technical Field

[0001] The present invention belongs to the technical field of document anti-counterfeiting, and in particular relates to an electronic document printing anti-counterfeiting and identification technology based on virtual printing. Background Art

[0002] With the widespread adoption of electronic signature technology, electronic documents need to be printed out as paper copies after signing for archiving or offline circulation. However, paper documents are easily tampered with or replaced after printing, resulting in inconsistencies with the electronic document and potentially posing legal risks. While existing anti-counterfeiting technologies can prevent document tampering to a certain extent, they still have some shortcomings.

[0003] Patent document CN202411460107.4 discloses "an anti-counterfeiting label based on dark watermark technology that can be verified offline, and a method for producing and identifying the same". Its core is to use an anti-counterfeiting label based on dark watermark technology that can be verified offline, identify it through the unique texture of the non-woven fabric and the embedded watermark information, use an ordinary printer to print the anti-counterfeiting pattern, and verify it offline through mobile phones and other devices. The shortcomings of this method are: 1. Dependence on physical labels and material properties, mainly physical carrier limitations: It needs to rely on non-woven labels and specific printing materials (such as photosensitive resin aluminum powder coatings) as anti-counterfeiting carriers, and cannot be directly applied to pure electronic files or scenarios that require flexible deployment (such as electronic documents, electronic signatures), which limits the scalability of the technology. There is also the fragility of physical features: the physical anti-counterfeiting features of the label (such as coatings, textures) may be damaged due to transportation wear or environmental factors (such as light, humidity), resulting in failure in dark watermark extraction. 2. The security risk of offline verification is reflected in the static nature of the key: offline verification requires pre-storing the key on a local device. If the key is leaked or the device is cracked, counterfeiters may be able to reverse engineer and generate an effective watermark, weakening the anti-counterfeiting effect. Dynamic updates are difficult: in an offline environment, it is difficult to update the key or watermark rules in a timely manner, and long-term use of fixed parameters can easily lead to mass counterfeiting. 3. The complexity of multi-step verification is reflected in the cumbersome multi-code combination verification process: the activation code must be scanned, the identification code must be identified, and the anti-counterfeiting code must be silk-screened. Consumers need to perform multiple operations, resulting in a poor user experience and the possibility of verification failure due to operational errors. The technical threshold of combining physical and digital features: maintaining the synergy between physical anti-counterfeiting features and digital watermarks simultaneously increases production and management costs.

[0004] Patent document CN202011439786.9 discloses "A method and system for preventing counterfeiting of printed paper documents with electronic signatures". The latter part of the technology adopts optical hidden digital anti-counterfeiting technology to generate and set it in the electronic signature area. The electronic document information of the electronic signature and the information in the printed paper document are obtained by scanning and compared. When the two are inconsistent, an alarm is automatically triggered. This method is mainly used for printing anti-counterfeiting of electronic documents with electronic signatures. Moreover, although optical digital watermark information is embedded around the electronic signature or at random positions in the document, it can prevent the signature from being forged, but it has limitations in the comprehensive protection of the document content. For example, other parts of the document (such as the main text, headers and footers, etc.) may not be effectively protected, and tampering with these parts will not affect the effectiveness of the anti-counterfeiting mark, and thus cannot effectively prevent the document as a whole from being tampered with. Summary of the Invention

[0005] The present invention aims to provide an electronic document printing anti-counterfeiting and identification method and system based on virtual printing. By embedding an invisible anti-counterfeiting mark in the printing process of an electronic document with an electronic signature, the consistency of the content of the paper document and the electronic document with the electronic signature is ensured, and the authenticity of the paper document and the authenticity of the signature and seal image can be quickly identified.

[0006] The technical solutions of the present invention are as follows: In a first aspect, the present application provides a method for anti-counterfeiting and identification of electronic documents based on virtual printing, which is implemented using a printing steganography technology based on nozzle voltage / heating pulse control, and the method comprises: (1) Data encoding and preprocessing: Calculate the hash value of the original electronic signature and store it in the digital signature library, perform hash expansion, and interleave the expanded encoded data bit by bit; (2) Steganography and embedding: Divide the printed page into a grid with a sub-millimeter grid, select the text edge or background area as the embedding point, fine-tune the printing voltage, and control the normal ink volume and ink shortage status; (3) Anti-interference printing: Repeatedly embed the same data in the four corners and center of the document for multiple copies; print special ink-deficient patterns on the edge of the page for positioning marks; use the temperature-voltage compensation function for temperature compensation during printing.

[0007] (4) Data extraction and verification: Collect and pre-process images of printed paper documents, compare the ink density of the processed images, decode and extract the original hash value, and compare it with the digital signature library. If they are consistent, the document is considered legal.

[0008] Further preferably, the calculation of the hash value of the electronic file of the original electronic signature is to generate a hash value by using a hash algorithm for the electronic file data of the 32-byte original electronic signature; and the hash extension is extended to 64 bytes through RS (64, 32) encoding.

[0009] Further preferably, the bit-by-bit interleaving arrangement is to rearrange the encoded data stream in a non-continuous and regularly dispersed manner according to a single bit as a basic unit, so as to maximize the physical position interval between adjacent logical bits. Specifically, a matrix rearrangement method or a pseudo-random permutation method can be used.

[0010] More preferably, the normal ink level is when the nozzle voltage is set to the printer's baseline value and the ink droplet coverage reaches above 85%, which is coded as 0. The ink shortage state is when the voltage is reduced by 0.5-1V to reduce the coverage below 70%, which is coded as 1. The difference in ink volume between the normal ink level and the ink shortage state is controlled to be within a Δ grayscale of <15%.

[0011] Furthermore, a paper type-voltage parameter mapping model is preferably used for dynamic compensation during steganography and embedding, adjusting the ink deficiency intensity based on the paper type to avoid reflective development. Paper types include glossy and matte finishes. The temperature-voltage compensation function is ΔT = 5°C → ΔV = 0.2V, meaning that for every 5°C increase in temperature, the voltage drops by 0.2V.

[0012] Further preferably, the ink dot density comparison is to calculate the ink dot density difference between the steganographic area and the adjacent normal area.

[0013] Further preferably, the decoding to extract the original hash value is to first decode the binary sequence and then apply RS decoding to repair bit errors to restore the original hash value.

[0014] In another aspect, the present application further provides an electronic document printing anti-counterfeiting and identification system based on virtual printing, the system comprising: Data encoding and preprocessing module: used to calculate the hash value of the electronic file of the original electronic signature and store it in the digital signature library, perform hash expansion, and interleave the expanded encoded data in bit order; Steganography and embedding module: used to divide the printed page into a sub-millimeter grid, select the text edge or background area as the embedding point, fine-tune the printing voltage, and regulate the normal ink volume and ink shortage status of printing, so as to control the ink volume difference below the human eye perception threshold.

[0015] Anti-interference printing module: used to repeatedly embed the same data in the four corners and center area of ​​the document for multiple copies; print special ink-deficient patterns on the edge of the page for positioning marks; and use the temperature-voltage compensation function for temperature compensation during printing.

[0016] Data extraction and verification module: Capture images of printed paper documents and pre-process them, compare the ink dot density of the processed images, decode and extract the original hash value, and compare it with the digital signature library. If they are consistent, the document is deemed legal.

[0017] Compared with the prior art, the beneficial effects of the present invention include the following aspects: 1. Seamless and concealed: Through sub-millimeter grid dispersed embedding, the difference in ink volume is controlled below the threshold of human eye perception.

[0018] 2. Double anti-counterfeiting: Based on the existing digital signature verification of the electronic document itself, the physical steganography anti-counterfeiting of the present invention is added to achieve double anti-counterfeiting, breaking through the limitations of traditional single anti-counterfeiting technology.

[0019] 3. Low-cost implementation: Compared with special inks (such as fluorescent / conductive inks), relying solely on ink volume control can reduce costs by 90%.

[0020] 4. Cross-device compatibility: Applicable to common inkjet printers (such as Epson, Canon), without hardware modification. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without creative work.

[0022] Figure 1 is a flow chart of an electronic document printing anti-counterfeiting and identification method based on virtual printing in an exemplary embodiment; Figure 2 is a schematic diagram of a process for steganographic printing of an anti-counterfeiting electronic document in an exemplary embodiment; Figure 3 is a flow chart of a voltage fine-tuning strategy in an exemplary embodiment; Figure 4 is a schematic diagram of print control in an exemplary embodiment; Figure 5 2 is a flow chart of identification and verification of anti-counterfeiting electronic documents in an exemplary embodiment. DETAILED DESCRIPTION

[0023] The core of the present invention is to provide an electronic document printing anti-counterfeiting and identification method based on virtual printing. Through the printing steganography technology based on nozzle voltage / heating pulse control, an invisible anti-counterfeiting mark is embedded in the printing process of the electronic document with electronic signature, ensuring the consistency of the content of the paper document and the electronic document with electronic signature. At the same time, it can quickly identify the authenticity of the paper document and the authenticity of the signature and seal image.

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] First, we explain and analyze the printing steganography technology based on nozzle voltage / heating pulse control.

[0026] This invention achieves micron-level ink volume differences on ordinary printing paper (such as A4 paper) by precisely adjusting the voltage or heating pulse of the printer nozzle, forming steganographic data that is invisible to the human eye but recognizable by machines. Its core design points are: Ink volume quantization coding: The 32-byte hash value (256 bits) is expanded to 512 bits through error correction coding, and the nozzle voltage is fine-tuned (±0.5V) to control the difference in single-dot ink coverage (e.g., 85% vs. 70%), corresponding to binary 0 / 1 coding.

[0027] Anti-visual perception design: Because the human eye's perception threshold for local ink volume differences is approximately 15% grayscale difference, data can be effectively concealed through sub-millimeter grid-based dispersed embedding (such as 0.1mm² / cell).

[0028] Physical robustness: Combining error-correcting codes (such as Reed-Solomon) with multi-region redundancy embedding to resist interference such as creases and stains.

[0029] The following describes the technical implementation steps of the present invention in detail with reference to exemplary embodiments: See also Figure 1 The electronic document printing anti-counterfeiting and identification method based on virtual printing is generally divided into two parts: steganographic printing and identification verification. First, the anti-counterfeiting mark is generated and written, then the paper document is printed, and finally verification is performed. Steganography is achieved by controlling physical printing through the method of the present invention.

[0030] See also Figure 2 , is an exemplary embodiment of the process of generating, writing, and printing a paper document of an anti-counterfeiting mark, which is specifically implemented as follows: 1. Data encoding and preprocessing First, the electronic document that has been electronically signed is encoded and preprocessed.

[0031] 1.1 Hash generation: Use a hash algorithm, such as the National Secret Hash Algorithm (SM3), to calculate the hash value of the original electronic file, and store the algorithm name and hash value in the digital signature library for subsequent verification.

[0032] 1.2 Hash Extension: After the 32-byte original electronic file data is hashed using a hash algorithm (such as SHA256 or SM3), the hash value is expanded to 64 bytes of redundant data using RS(64,32) encoding, supporting 16-byte error correction. RS refers to the Reed-Solomon code, a forward error correction (FEC) channel code.

[0033] Embed RS code in QR code, which can still be scanned even if it is partially damaged 1.3 Interleaving: The encoded data is interleaved bit by bit to avoid data loss due to continuous physical damage.

[0034] Bit-interleaving is a specific processing method in data protection technology. Its core concept is to rearrange the encoded data stream in a non-contiguous and regularly distributed manner, using individual bits as the basic unit. This forces originally logically continuous data bits to be dispersed to non-adjacent locations during physical storage or transmission. Matrix rearrangement and pseudo-random permutation methods can be used.

[0035] In the present invention, the position of each bit of the encoded data is shuffled according to a specific rule. This arrangement maximizes the physical position interval between adjacent logical bits, preventing local physical damage from affecting multiple consecutive bits at the same time and causing data loss.

[0036] 2. Steganographic Unit Design and Embedding 2.1 Grid Division: Divide the printed page into a submillimeter grid. For example, divide an A4 page into a 0.1mm x 0.1mm grid, corresponding to 600dpi printing accuracy. Select text content or background areas as the embedding points for the anti-counterfeiting mark. This significantly increases information density, for example, to 0.01mm² / bit at 600dpi, making it 20 times more concealable than traditional QR codes.

[0037] 2.2 Voltage fine-tuning strategy: Specifically, the printing voltage is fine-tuned to control normal ink levels and low-ink states. Fine-tuning the printhead voltage (±0.5V) controls the difference in single-dot ink coverage (e.g., 85% vs. 70%), corresponding to binary 0 / 1 encoding.

[0038] See the fine-tuning process for Figure 3 : Detect the nozzle position in real time, calculate the grid corresponding to the position, and then query the grid code. When the code is 0, call the driver to set the voltage for printing, and then return to continue to detect the nozzle position in real time. When the code is 1, continue to detect the nozzle position in real time.

[0039] In this exemplary embodiment, because the embedded data is 64 bytes, it corresponds to 64*8=512 bits = 512 0s|1s = 512 grids, meaning 512 grids are required to store this data. A grid code is a grid subscript used to quickly locate a grid. For example, in a 0.1mm*0.1mm grid layout, an A4 sheet of paper can be divided into 6111,000 grids. The grid code is the serial number of each of these 6111,000 grids, and can also correspond to memory in a program. The serial number and area can be quickly converted, meaning that the binary 0 / 1 code represents the data, and the grid code represents the location.

[0040] Among them, controlling the normal ink volume and ink shortage status of printing refers to: Normal ink volume: The nozzle voltage is set to the reference value (such as Epson 30V), and the ink droplet coverage rate is above 85% (code 0).

[0041] Ink shortage: Reduce the voltage by 0.5-1V (e.g. 29V) to reduce the coverage to below 70% (code 1), and control the ink volume difference to a level that is imperceptible to the human eye (Δ grayscale <15%).

[0042] At the same time, dynamic compensation can also be performed: the ink shortage intensity is adjusted according to the paper type (glossy / matte). Glossy paper requires a smaller voltage difference to avoid reflective development.

[0043] In this way, through the voltage-grayscale nonlinear control model, the steganographic area ΔE ≤ 3.5 (CIELab color difference) can be made, reaching the visually indistinguishable level.

[0044] 3. Print control and anti-interference 3.1 Multiple replication: The same data, i.e. identification data, is repeatedly embedded in the four corners and the center of the document. It is a preset fixed value, similar to the three squares on a QR code, and is used to prevent data damage. In the event of local damage, it can be restored by majority voting.

[0045] 3.2 Positioning Mark: Print special ink-out patterns (such as L-shaped corner marks) on the edge of the document, control the voltage to achieve ink-out status, assist in aligning the grid during scanning, and be used for positioning and data analysis.

[0046] like Figure 4 As shown, when printing PDF, add 4 positioning intersections, and divide the area into 0.01mm equal parts within the 4 positioning intersections. 2 Each grid is coded as 0 or 1. When a grid is coded as 0 and the inkjet nozzle moves to that grid area, the voltage is reduced and the voltage is restored in the grid area coded as 1. 3120, 3121, 3720, and 3721 in the figure refer to the grid numbers.

[0047] 3.3 Temperature Compensation: The printing environment temperature is monitored in real time, and the voltage is dynamically adjusted to offset changes in ink viscosity. Specifically, temperature compensation is performed during printing using a temperature-voltage compensation function: ΔT = 5°C → ΔV = 0.2V. This function indicates that for every 5°C increase in temperature, the voltage drops by 0.2V. This overcomes the impact of ambient temperature changes on stegoscopy stability.

[0048] Through the above processing, an error correction capacity of 16 bytes / square centimeter of printed media can be achieved, and >99% data integrity can be maintained in folding and soiling scenarios.

[0049] 4. Data Extraction and Verification like Figure 5 As shown, this step is to verify the anti-counterfeiting of the anti-counterfeiting printed paper document obtained above, using a multi-modal verification system.

[0050] 4.1 Image acquisition: Scan the anti-counterfeiting printed paper document to obtain the document image, and then grayscale, denoise and perspective correct the image.

[0051] Here, you can use a 1200dpi scanner to scan.

[0052] Conventional methods can be used to grayscale, denoise, and correct perspective on images. For example, image grayscale can employ weighted averaging, maximum / average methods, and color space conversion methods. These methods convert color images into single-channel grayscale images containing only brightness information. By removing color information (RGB channels), each pixel's brightness is compressed to a range of 0-255. Their core goal is to reduce data size and improve processing efficiency while preserving the image's structural features for subsequent analysis (such as edge detection and feature extraction). Image denoising aims to remove or reduce noise (such as Gaussian noise and salt-and-pepper noise) in the image and restore the original information. Methods such as spatial filtering, frequency filtering, and deep learning can be employed. Image perspective correction uses geometric transformations to correct image distortion caused by shooting angles (such as converging lines on buildings or tilted documents) and restore the true proportions and shape of objects. Its core goal is to eliminate perspective projection distortion and maintain parallel lines in the image. Implementation methods include control point selection, homography matrix calculation, geometric transformations, and post-processing.

[0053] 4.2 Steganalysis Detection: The processed image is subjected to the following detection and verification, including: Error correction: Apply RS decoding to fix bit errors and restore the original hash value of the document.

[0054] Legality determination: The extracted original hash value is compared with the hash value pre-stored in the digital signature library. If the comparison is consistent, the document is determined to be legal.

[0055] Through the above two steps, a dual-check mechanism of "physical layer RS ​​error correction-logical layer hash verification" is established, which can make the error tolerance reach the physical damage area ≤ 30%.

[0056] In a further exemplary embodiment, a virtual printing-based electronic document printing anti-counterfeiting and identification system for implementing the above method is provided, the system comprising: Data encoding and preprocessing module: used to calculate the hash value of the electronic file of the original electronic signature and store it in the digital signature library, perform hash expansion, and arrange the expanded encoded data in bit interleaving.

[0057] Steganography and embedding module: used to divide the printed page into a sub-millimeter grid, select the text edge or background area as the embedding point, fine-tune the printing voltage, and regulate the normal ink volume and ink shortage status of printing, so as to control the ink volume difference below the human eye perception threshold.

[0058] Anti-interference printing module: used to repeatedly embed the same data in the four corners and center area of ​​the document for multiple copies; print special ink-deficient patterns on the edge of the page for positioning marks; and use the temperature-voltage compensation function for temperature compensation during printing.

[0059] Data extraction and verification module: Capture images of printed paper documents and pre-process them, compare the ink dot density of the processed images, decode and extract the original hash value, and compare it with the digital signature library. If they are consistent, the document is deemed legal.

[0060] It can be seen from the above embodiments that the technical solution of the present invention has at least the following unique features compared with the prior art: 1. Multi-level fault-tolerant coding architecture A two-level protection mechanism of "hash extension-interleaving coding" was designed. The 32-byte hash is expanded to 64 bytes of redundant data through RS (64,32) coding, and bit interleaving technology is combined to improve the ability to resist physical damage (error correction capacity reaches 25%).

[0061] A digital fingerprint dynamic verification system was established to achieve closed-loop verification of hash value generation, coding expansion and digital signature library.

[0062] 2. Micro-scale Steganographic Embedding Method Using a unique steganographic method based on printing voltage regulation, the ink volume control at the 0.1mm grid level (grayscale variation <15%) is achieved through ±1V voltage fine-tuning.

[0063] A dynamic compensation strategy is proposed and a paper type-voltage parameter mapping model is established to solve the steganographic visibility problem on glossy / matte paper.

[0064] 3. Adaptive anti-interference system A five-region redundant embedding architecture (four corners + center) is designed, combined with L-shaped positioning markers to achieve rotation-invariant detection.

[0065] A temperature-voltage compensation function (ΔT=5℃→ΔV=0.2V) was constructed to overcome the impact of ambient temperature changes on steganographic stability.

[0066] 4. Multimodal verification system Create an ink dot density differential detection algorithm to achieve sub-pixel decoding under 1200dpi scanning by comparing the grayscale of adjacent areas.

[0067] A dual-check mechanism of "physical layer RS ​​error correction-logical layer hash verification" has been established, with an error tolerance of ≤30% of the physical damage area.

[0068] It can be seen that this technical solution forms a technical closed loop in the three dimensions of coding structure, steganography method, and environmental adaptability, and can build a complete combination including data processing algorithms, printing control devices, and verification systems for the document security field.

Claims

1. A method for preventing and identifying electronic document printing based on virtual printing, characterized by: The method comprises: Data encoding and preprocessing: Calculate the hash value of the original electronic signature and store it in the digital signature library, perform hash expansion, and interleave the expanded encoded data bit by bit; Steganography and embedding: Divide the printed page into a sub-millimeter grid, select text edges or background areas as embedding points, fine-tune the printing voltage, and control the normal ink level and ink shortage status of printing to keep the ink level difference below the human eye's perception threshold; Anti-interference printing: Repeat the same data in the four corners and center of the document to make multiple copies; print special ink-missing patterns on the edges of the document to mark the location; use the temperature-voltage compensation function to compensate for temperature during printing; Data extraction and verification: Capture images of printed paper documents and pre-process them, compare the ink density of the processed images, decode and extract the original hash value, and compare it with the digital signature library. If they are consistent, the document is deemed legal.

2. The method for preventing and identifying electronic document printing based on virtual printing according to claim 1, characterized in that: The calculation of the electronic file hash value of the original electronic signature is to generate a hash value by using a hash algorithm for the electronic file data of the 32-byte original electronic signature; the hash extension is extended to 64 bytes through RS (64, 32) encoding.

3. The electronic document printing anti-counterfeiting and identification method based on virtual printing according to claim 1 is characterized in that: The bit-by-bit interleaving arrangement is to rearrange the encoded data stream in a non-continuous and regularly dispersed manner based on a single bit as a basic unit, so as to maximize the physical position interval between adjacent logical bits. Specifically, a matrix rearrangement method or a pseudo-random permutation method can be used.

4. The electronic document printing anti-counterfeiting and identification method based on virtual printing according to claim 1 is characterized in that: The normal ink volume is when the nozzle voltage is set to the printer's base value, and the ink drop coverage rate reaches more than 85%, coded as 0; the ink shortage state is when the voltage is reduced by 0.5-1V, so that the coverage rate drops below 70%, coded as 1.

5. The electronic document printing anti-counterfeiting and identification method based on virtual printing according to claim 4 is characterized in that: The difference in ink volume between normal ink volume and ink shortage state is controlled within Δ grayscale < 15%.

6. The electronic document printing anti-counterfeiting and identification method based on virtual printing according to claim 1 is characterized in that: During steganography and embedding, a paper type-voltage parameter mapping model is used for dynamic compensation. The ink deficiency intensity is adjusted according to the paper type to avoid reflective development. The paper types include glossy and matte.

7. The electronic document printing anti-counterfeiting and identification method based on virtual printing according to claim 1 is characterized in that: The temperature-voltage compensation function is ΔT=5°C→ΔV=0.2V, that is, the voltage drops by 0.2V for every 5°C increase in temperature.

8. The electronic document printing anti-counterfeiting and identification method based on virtual printing according to claim 1 is characterized in that: The ink dot density comparison is to calculate the difference in ink dot density between the steganographic area and the adjacent normal area.

9. The electronic document printing anti-counterfeiting and identification method based on virtual printing according to claim 1 is characterized in that: Decoding to extract the original hash value involves first decoding the binary sequence and then applying RS decoding to repair bit errors and restore the original hash value.

10. An electronic document printing anti-counterfeiting and identification system based on virtual printing, characterized in that: include: Data encoding and preprocessing module: used to calculate the hash value of the electronic file of the original electronic signature and store it in the digital signature library, perform hash expansion, and interleave the expanded encoded data in bit order; Steganography and Embedding Module: This module divides the printed page into a sub-millimeter grid, selects text edges or background areas as embedding points, fine-tunes the printing voltage, and regulates normal and low-ink states, keeping the ink level difference below the human eye's perception threshold. Anti-interference printing module: used to repeatedly embed the same data in the four corners and center area of ​​the document for multiple copies; Print special ink-deficient patterns on the edge of the page as positioning marks; use the temperature-voltage compensation function to perform temperature compensation during printing; Data extraction and verification module: Capture images of printed paper documents and pre-process them, compare the ink dot density of the processed images, decode and extract the original hash value, and compare it with the digital signature library. If they are consistent, the document is deemed legal.

Images