Digital and physical mixed signature method and device, electronic equipment and storage medium
By generating and printing composite digital signatures for electronic documents, and utilizing the random fiber distribution characteristics of paper documents, the problem of achieving a balance between low cost, high security, and convenient verification in existing technologies is solved, thus realizing efficient anti-counterfeiting for ordinary printed materials.
Patent Information
- Application Number
- CN202511830101.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-05
- Publication Date
- 2026-05-12
AI Technical Summary
Existing anti-counterfeiting technologies cannot achieve an ideal balance between the three key dimensions of low cost, high security, and convenient verification. In particular, they cannot effectively solve the problem of how to provide anti-counterfeiting measures for ordinary printed materials that can be bound to specific paper types and can be verified independently and conveniently.
By obtaining the document content hash value of the electronic document and the random fiber distribution characteristics of the paper document, a paper fingerprint hash value is generated. After combining them, a digital signature is generated using a signing private key. A unique physical entity bound to the composite digital signature is then printed out.
It achieves low-cost, high-security anti-counterfeiting. Users can complete the process using common devices such as computers and printers. The verification process is simple and quick, without relying on special equipment or complex procedures, and can effectively prevent counterfeiting and tampering.
Smart Images
Figure CN122020728A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of information security technology, specifically to a digital-physical hybrid signature method, device, electronic device, and storage medium. Background Technology
[0002] With the rapid development of information technology, electronic documents have become the mainstream medium for business activities and daily office work due to their ease of storage, transmission, and processing. However, in many key areas, such as legal contracts, government approvals, financial instruments, and academic certificates, paper documents still play an irreplaceable role due to their physical nature, intuitiveness, and long-established legal validity. Ensuring the authenticity, integrity, and non-repudiation of these paper documents, and preventing forgery, alteration, and repudiation, has long been a core issue that urgently needs to be addressed in the field of information security.
[0003] To address these challenges, the industry has developed various anti-counterfeiting technologies, such as digital watermarking and visual cryptography, special anti-counterfeiting paper and printing solutions, and pure digital signature verification schemes. However, existing anti-counterfeiting technologies all have inherent limitations, failing to achieve an ideal balance between low cost, high security, and convenient verification. In particular, they cannot effectively solve the core problem of providing ordinary printed documents with an anti-counterfeiting method that can both be bound to specific paper types and be easily verified independently. Therefore, the market urgently needs a new technological solution to overcome the limitations of existing technologies. Summary of the Invention
[0004] In view of this, this application provides a digital-physical hybrid signature method, device, electronic device and storage medium. The main purpose is to solve the problem that existing anti-counterfeiting technologies all have their own inherent defects and cannot achieve an ideal balance in the three key dimensions of low cost, high security and convenient verification. In particular, they cannot effectively solve the technical problem of how to provide an anti-counterfeiting means for ordinary printed documents that can be bound to specific paper and can be independently and conveniently verified.
[0005] According to a first aspect of this application, a digital-physical hybrid signature method is provided, the method comprising: Obtain the electronic document to be signed and calculate the document content hash value of the electronic document; Obtain the random fiber distribution characteristics of the paper document carrying the electronic document, and generate a paper fingerprint hash value based on the random fiber distribution characteristics, wherein the paper fingerprint hash value is used to characterize the uniqueness of the paper document; The document content hash value and the paper fingerprint hash value are combined, and the combined hash value data is digitally signed using a signing private key to generate a composite digital signature. The composite digital signature is associated with the electronic document, and the electronic document is output for printing, so that the printed paper document is the only physical entity bound to the composite digital signature.
[0006] According to a second aspect of this application, a digital-physical hybrid signature device is provided, the device comprising: The acquisition module is used to acquire the electronic document to be signed and calculate the document content hash value of the electronic document; A generation module is used to obtain the random fiber distribution characteristics of the paper document carrying the electronic document, and generate a paper fingerprint hash value based on the random fiber distribution characteristics, wherein the paper fingerprint hash value is used to characterize the uniqueness of the paper document; The processing module is used to combine the document content hash value with the paper fingerprint hash value, and use a signing private key to perform digital signature processing on the combined hash value data to generate a composite digital signature. The association module is used to associate the composite digital signature with the electronic document and output the electronic document for printing, so that the printed paper document is the only physical entity bound to the composite digital signature.
[0007] According to a third aspect of this application, a non-transitory computer-readable storage medium storing computer instructions is provided, wherein the computer instructions are used to cause a computer to execute the digital-physical hybrid signature method of the first aspect described above.
[0008] According to a fourth aspect of this application, an electronic device is provided, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the digital-physical hybrid signature method of the first aspect described above.
[0009] By employing the above technical solutions, this application provides a digital-physical hybrid signing method, apparatus, electronic device, and storage medium. Compared with existing technologies, this application can obtain an electronic document to be signed and calculate the document content hash value of the electronic document; obtain the random fiber distribution characteristics of the paper document carrying the electronic document and generate a paper fingerprint hash value based on the random fiber distribution characteristics, wherein the paper fingerprint hash value is used to characterize the uniqueness of the paper document; combine the document content hash value and the paper fingerprint hash value, and perform digital signature processing on the combined hash value data using a signing private key to generate a composite digital signature; associate the composite digital signature with the electronic document and output the electronic document for printing, so that the printed paper document is the unique physical entity bound to the composite digital signature.
[0010] The solution described in this application generates a paper fingerprint hash value by obtaining the random fiber distribution characteristics of the paper document carrying the electronic document. This random fiber distribution is naturally formed by the paper itself, eliminating the need for expensive anti-counterfeiting materials or complex manufacturing processes. This application directly utilizes this existing characteristic, without requiring special customization or modification of the paper, significantly reducing costs. Furthermore, the entire solution is primarily based on software algorithms and conventional printing equipment. No specialized anti-counterfeiting hardware is required. Users can complete the entire process using only common computers and printers, further reducing implementation costs.
[0011] This application ensures the integrity and immutability of document content by calculating the document content hash value of the electronic document. Simultaneously, a paper fingerprint hash value is generated based on the random fiber distribution characteristics of the paper document; this paper fingerprint hash value uniquely represents the characteristics of the paper document. These two hash values are combined, and a signing private key is used to digitally sign the combined hash value data, generating a composite digital signature. This dual hash binding mechanism ensures that any tampering with the document content or paper will result in a hash value mismatch, making it easily detectable and significantly improving anti-counterfeiting security.
[0012] The combined hash value data is digitally signed using a signing private key. Digital signatures are non-repudiable and unique. Only the verifier with the corresponding public key can verify the validity of the signature, and the signer cannot deny that they have signed the document, effectively preventing forgery and tampering.
[0013] Once a composite digital signature is associated with an electronic document, the printed paper document becomes the unique physical entity bound to the composite digital signature. Verification requires no additional external systems or complex verification processes. The verifier can obtain the fiber distribution characteristics of the paper document, recalculate the paper fingerprint hash value, and simultaneously obtain the document content hash value. These are then combined and used with a public key to verify the validity of the composite digital signature. The entire verification process is relatively simple, requiring no complex operational steps or specialized knowledge. Furthermore, the verification method is independent of specific environments or conditions, improving the convenience and flexibility of verification.
[0014] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description
[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 A flowchart illustrating a digital-physical hybrid signature method provided in an embodiment of this application is shown. Figure 2 This paper illustrates a system architecture diagram of a digital-physical hybrid signature system provided in an embodiment of this application. Figure 3 A flowchart illustrating another digital-physical hybrid signature method provided in an embodiment of this application is shown; Figure 4 A schematic diagram of the structure of a digital-physical hybrid signature device provided in an embodiment of this application is shown. Detailed Implementation
[0018] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of this application, including various details to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.
[0019] The following description, with reference to the accompanying drawings, describes a digital-physical hybrid signature method, apparatus, electronic device, and storage medium according to embodiments of this application.
[0020] To address the inherent limitations of existing anti-counterfeiting technologies, which fail to achieve an ideal balance between low cost, high security, and convenient verification, particularly in providing a robust anti-counterfeiting method for ordinary printed documents that can both bind to specific paper types and offer independent and convenient verification, this application provides a digital-physical hybrid signature method. Figure 1 As shown, the method includes: Step 101: Obtain the electronic document to be signed and calculate the document content hash value of the electronic document.
[0021] Among them, digital-physical hybrid signature can be a new signature paradigm. It not only cryptographically signs the digital content of electronic documents, but also binds the inherent characteristics of the physical paper that carries the content to the signature, thereby generating a composite digital signature that simultaneously ensures the integrity of digital information and the authenticity of the physical carrier.
[0022] This application can be divided into an electronic document signing process and a paper document verification process.
[0023] The electronic document signing process can be integrated into a signing platform or a standalone app. For example, a user can upload an electronic document to be signed via a mobile app. Upon receiving the document, the app's document processing module determines its format. If the document is in DOCX or another format, it first standardizes the document to convert it to PDF. Then, it reads the entire document's byte stream and uses a cryptographic hash function (such as SHA-256) to calculate the document content hash value (H_doc).
[0024] The document content hash value is a unique, fixed-length digital digest used to verify the integrity of electronic document content and prevent tampering. The cryptographic hash function is an algorithm that maps input data of arbitrary length to a fixed-length, seemingly random output value (hash value). It possesses characteristics such as one-wayness (it cannot be reversed) and collision resistance (it is difficult to find two different inputs that produce the same hash value), which are fundamental to ensuring the immutability of paper fingerprint hash values and document content hash values.
[0025] Collision resistance is one of the core properties of cryptographic hash functions. It means that it is computationally infeasible to intentionally find two different input messages that produce the same hash value. This property ensures that it is virtually impossible to forge different sheets of paper with the same hash value (H_paper).
[0026] Step 102: Obtain the random fiber distribution characteristics of the paper document carrying the electronic document, and generate a paper fingerprint hash value based on the random fiber distribution characteristics. The paper fingerprint hash value is used to characterize the uniqueness of the paper document.
[0027] In this embodiment of the disclosure, obtaining the random fiber distribution characteristics of the paper document carrying the electronic document and generating a paper fingerprint hash value based on the random fiber distribution characteristics may specifically include: Step 1: Acquire multiple consecutive digital images within a predetermined area of the paper document using an image acquisition device; the paper document can be ordinary A4 paper. Step 2: By analyzing the perspective changes of multiple consecutive digital images, determine whether the paper document is a three-dimensional paper document; Step 3: If the paper document is a three-dimensional paper document, obtain the random fiber distribution characteristics of the three-dimensional paper document, and generate a paper fingerprint hash value based on the random fiber distribution characteristics. Specifically, this may include: The digital image is preprocessed, and a local feature algorithm that is insensitive to illumination and rotation is used to extract random fiber distribution features from the preprocessed digital image to generate a digital feature vector (F_paper). The preprocessing includes at least one of grayscale conversion, contrast enhancement, distortion correction and noise reduction. The feature points include at least one of paper fiber interlacing points and impurity points. Perform a hash operation on the digital feature vector (F_paper) to obtain the paper fingerprint hash value (H_paper).
[0028] In this embodiment, the user can place the printed paper document containing the electronic document in a suitable position and open the paper fingerprint collection module of the mobile application APP. Following the real-time guidance and prompts on the UI interface from the visual guidance module, the user can point the device's camera at a predefined collection area on the paper document and collect multiple consecutive digital images of that area at a predetermined frame rate (e.g., 15 frames per second).
[0029] Real-time guidance and prompts, such as instructing users on how to position and focus the paper, ensure that a clear and usable image of the paper is captured. The capture area is a pre-defined specific region on the paper document (usually located at the corner of the document, such as a 5mm x 5mm square), which is dedicated to capturing the fibrous features of the paper through an image sensor. The capture area is typically identified by a corner marker automatically generated by the system during printing.
[0030] During the data acquisition process, the mobile application can ask the user to slightly shake their phone. This allows the application's backend anti-attack design module to calculate the minute displacements and perspective changes of key points between adjacent frames of multiple consecutive digital images, determining that the subject is a three-dimensional, textured paper surface, rather than a flat photograph. If the determination is successful, the data acquisition continues.
[0031] It can perform preprocessing on acquired digital images, such as grayscale conversion, contrast enhancement, distortion correction, and noise reduction. For example, digital images may have problems such as color interference and uneven brightness. After grayscale conversion, the digital image becomes a black and white image. Then, histogram equalization technology is used to enhance the contrast between fiber texture and background. Based on the corner position, it can correct image distortion caused by the tilt angle of the mobile phone camera to ensure the accuracy of the image's geometric shape. Gaussian filters can be used to remove random noise in digital images.
[0032] Local feature extraction algorithms (such as ORB, SIFT, or convolutional neural networks) that are insensitive to illumination and rotation can be used to extract feature points of random fiber distribution from the preprocessed digital image. These feature points can include information such as the location, orientation, and scale of microscopic features such as paper fiber interlacing points, impurity points, and endpoints. The extracted feature points are then converted into a digital feature vector (F_paper).
[0033] The random fiber distribution feature can be a unique physical pattern formed naturally at the microscopic level during the manufacturing process of ordinary paper, consisting of the random distribution and interweaving of cellulose fibers, as well as impurities. This feature is unique and cannot be cloned, and is the physical basis of the anti-counterfeiting technology of this application.
[0034] The hash generation module of the mobile application can use a cryptographic hash function (such as SHA-256) to calculate the digital feature vector (F_paper) to obtain the paper fingerprint hash value (H_paper). The paper fingerprint hash value is a fixed-length, unique digital digest (such as a long string of hexadecimal numbers), which represents the "physical identity card" of the paper document.
[0035] In terms of physical conditions, since paper fibers are randomly formed during the manufacturing process, they cannot be precisely controlled or replicated. No copying, scanning, or printing technology can reproduce the microscopic fiber structure of another sheet of paper.
[0036] Mathematically, even if an attacker theoretically obtains the original H_paper, due to the one-way and collision-resistant nature of the hash function, he cannot reverse engineer the corresponding fiber features, let alone create a paper with the same feature distribution.
[0037] Therefore, the H_current of any photocopy or other printout will necessarily not be equal to the original H_paper, and the verification will fail immediately. This application elevates the cornerstone of anti-counterfeiting from "difficult-to-reproduce patterns" to the higher dimension of "unclonable physical randomness," thus making this application extremely secure and effectively preventing counterfeiting.
[0038] Secondly, this application has extremely low cost and is easy to popularize. Specifically, this application does not require any special paper, special ink, or holographic film. It utilizes the inherent and free material properties of ordinary A4 paper fibers, thus reducing costs to zero.
[0039] Secondly, this application does not require specialized verification equipment such as banknote detectors or ultraviolet lamps. It utilizes readily available and necessary hardware, such as smartphone cameras and printers, thus reusing existing equipment.
[0040] Finally, the verification process of this application is self-contained (only requiring comparison of hash values), without the need to query the central database (some QR code anti-counterfeiting requires online verification every time to prevent copying), saving long-term database maintenance and query service costs.
[0041] Therefore, this application achieves a significant reduction in costs by reusing existing resources (paper characteristics, mobile phones, printers) and eliminating dependencies (special materials, dedicated equipment, centralized services), enabling high-level anti-counterfeiting technology to "enter ordinary households".
[0042] Step 103: Combine the document content hash value with the paper fingerprint hash value, and use the signing private key to digitally sign the combined hash value data to generate a composite digital signature.
[0043] In this embodiment of the disclosure, the composite signature generation module of the mobile application (APP) can concatenate the document content hash value and the paper fingerprint hash value to obtain concatenated hash value data. Then, the user's digital certificate private key can be used to digitally sign this concatenated data to generate a composite digital signature.
[0044] Digital certificates are like "identity cards" in the online world. They are issued by trusted Certificate Authorities (CAs) and contain the user's public key, identity information, and the CA's signature to prove ownership of the public key.
[0045] Step 104: Associate the composite digital signature with the electronic document and output the electronic document for printing, so that the printed paper document is the only physical entity bound to the composite digital signature.
[0046] In this embodiment of the disclosure, the generated composite digital signature can be embedded back into the electronic document (e.g., as an advanced signature for a PDF), and then the mobile application (APP) can drive a printer to print out the signed paper document with a collection area mark. At this time, the printed paper document is a unique physical entity bound to the composite digital signature. Simultaneously, the signing service communicates with a CA (Certificate Authority) to verify the certificate's validity and interacts with a record-keeping database to store the record.
[0047] The evidence storage database, located on the server side, securely stores associated information for each signing action. This information may include: composite digital signatures, signing timestamps, document hashes, paper fingerprint hashes, signer certificates, and other relevant data. It provides original evidence for potential dispute audits.
[0048] In this embodiment of the disclosure, the paper document verification process can be integrated into a verification platform or a standalone app. Specifically, it may include: Obtain the composite digital signature corresponding to the paper document, and use the public key to decrypt the paper fingerprint hash value (H_paper) from the composite digital signature. Collect the current digital feature vector of a predetermined area of the paper document and calculate the current feature hash value (H_current) of the current digital feature vector. Verify whether the on-site feature hash value (H_current) matches the paper fingerprint hash value (H_paper); If the Hamming distance between the on-site feature hash value (H_current) and the paper fingerprint hash value (H_paper) is less than the preset Hamming distance threshold, then the on-site feature hash value (H_current) matches the paper fingerprint hash value (H_paper), and the paper document is determined to be the physical original associated with the composite digital signature; If the Hamming distance between the on-site feature hash value (H_current) and the paper fingerprint hash value (H_paper) is greater than or equal to the preset Hamming distance threshold, then the on-site feature hash value (H_current) and the paper fingerprint hash value (H_paper) do not match, and the paper document is determined to be a forgery or a copy.
[0049] In this embodiment, for a signed electronic document or its printed paper copy to be verified, to obtain the composite digital signature, the verification app can first be opened. The signature extraction and decryption module of the verification app can be used to scan the QR code on the paper document. The QR code may contain a URL pointing to the electronic document. This URL can be used to obtain index information associated with the composite digital signature. Based on the index information, the verification app can obtain the composite digital signature corresponding to the paper document from the server or blockchain. From the electronic document verification, the electronic document can be directly parsed to extract the composite digital signature, which can then be decrypted using the accompanying public key certificate to obtain the original H_doc and H_paper.
[0050] The verification app's on-site paper fingerprint collection module guides the user to focus and capture multiple consecutive digital images of the same paper document from the same collection area. The images are then pre-processed, including grayscale conversion, contrast enhancement, distortion correction, and noise reduction.
[0051] The ORB algorithm can be used to extract feature points of the current random fiber distribution from the preprocessed digital image, generating a current digital feature vector (F_current). The SHA-256 algorithm can then be used to calculate the current digital feature vector, yielding the on-site feature hash value (H_current). This on-site feature hash value can be the hash value calculated during the verification process after on-site data collection and feature extraction of the area of the paper document to be verified. This value is then compared with the hash value of the original paper fingerprint decrypted from the composite digital signature to determine whether the current paper document is the original.
[0052] The integrity verification module of the verification app can use a public key to decrypt the paper fingerprint hash value (H_paper) from the composite digital signature. It then verifies whether the on-site feature hash value (H_current) matches the paper fingerprint hash value (H_paper) to verify whether the paper document is the original.
[0053] As one possible approach, the Hamming distance between the on-site feature hash value (H_current) and the paper fingerprint hash value (H_paper) can be calculated. Assuming a preset Hamming distance threshold of 5, if the calculated Hamming distance is less than 5, it is determined that the on-site feature hash value (H_current) and the paper fingerprint hash value (H_paper) match, and the paper document is the physical original associated with the composite digital signature; if the Hamming distance is greater than or equal to 5, it is determined that the paper document is a forgery or a copy.
[0054] For embodiments of this disclosure, the paper document verification process may further include: Use the public key to decrypt the document content hash value (H_doc) from the composite digital signature; Identify and calculate the current document content hash value of paper documents; Verify whether the hash value of the current document content is equal to the hash value of the document content; If the current document content hash value is equal to the document content hash value, it is determined that the document content of the paper document has not been tampered with; If the current document content hash value is not equal to the document content hash value, it is determined that the document content of the paper document has been tampered with.
[0055] As one possible approach, the document content hash (H_doc) can be decrypted from a composite digital signature using a public key.
[0056] The verification app uses OCR to recognize the content of a paper document and then recalculates its hash value to obtain the current document content hash value. It can then verify whether the current document content hash value is equal to the original document content hash value. If they are equal, the document content is determined to be unaltered; if they are not equal, the document content is determined to have been altered. In this example, they are equal, so the document content is determined to be unaltered. The final verification result is displayed as a green checkmark, indicating that the paper document is the original and has not been altered.
[0057] In this embodiment of the disclosure, the collection area is designed on the page containing key information (such as signatures and amounts). When calculating the document content hash value, the content of this page can be hashed together. For example, during the signing process, when the document processing module calculates the document content hash value, it not only performs a hash calculation on the entire document content, but also performs a separate hash calculation on the page containing the collection area and key information, and stores the hash value of this page in association with the overall document hash value. During the verification process, if someone attempts to replace any page, it will cause a mismatch between the overall document hash value and the hash value of that page, thereby preventing page-swapping attacks. For example, assuming the original document's page hash value containing key information is "m1n2o3p4...", if someone replaces this page, the recalculated page hash value becomes "q5r6s7t8...", which does not match the original hash value, thus indicating a page-swapping attack.
[0058] For embodiments of this disclosure, such as Figure 2 The system architecture diagram shown clearly illustrates the network interaction process between the various modules of the system: 1. Signing Process (Digital) physics) Path: Mobile Application (APP) internet Signing service; Data flow: The mobile application (APP) collects document hashes and paper fingerprint hashes; the data is sent to the cloud signing service via the Internet; the signing service communicates with the CA certification center to verify the validity of the certificate and interacts with the evidence storage database to store the record; The signing service generates a composite digital signature and returns it to the mobile application (APP); the mobile application then drives the printer to print out the signed paper document with the collection area marked.
[0059] 2. Verification Process (Physical) number) Path: Mobile Application (APP) internet Verification service; Data flow: The mobile application takes another picture of the paper document collection area and generates the current fingerprint hash; it sends a verification request to the verification service via the Internet; the verification service extracts information from the request or queries the corresponding original record from the evidence database; the verification service executes the core comparison logic (on-site hash vs. evidence hash) and returns the verification result to the mobile application.
[0060] 3. Key Topological Features Centralized services: The signing and verification services are the core hubs of the system, handling all core logic; Star topology: All clients (mobile applications APP) communicate directly with the central cloud service. It is a typical cloud-client structure that is easy to expand and manage. Hybrid Network: The system includes wireless internet (mobile network / Wi-Fi) and local connectivity (Bluetooth / USB driver printer), and the architecture diagram clearly distinguishes these two connection methods; Inter-module interfaces: Modules communicate with each other through well-defined API interfaces, ensuring loose coupling and maintainability of the system.
[0061] This architecture diagram shows that this application is a typical SaaS (Software as a Service) system, where users can enjoy powerful security services through a lightweight client (mobile APP), while complex cryptographic operations and evidence management are handled by the cloud platform.
[0062] For embodiments of this disclosure, such as Figure 3 As shown: Step 1: Signing Process (Digital World) (Physical World) 1. Document preparation: Users upload the electronic documents to be signed to the platform; 2. Printing and Placement: The user prints the document on plain A4 paper. The system can generate a clear "Collection Area" marker (such as an L-shaped corner mark, specifying the scanning range) in the lower right corner of the document; 3. Collect physical fingerprints: The user opens the mobile app, and the signing process guides them to focus and photograph the "collection area" on the document. The app executes the following in the background: F_paper=extract_paper_features(camera_image) / / Extract paper feature vectors H_paper=sha256(F_paper) / / Generate paper fingerprint hash 4. Generate compound signatures: H_doc=sha256(pdf_bytes) / / Calculate the document content hash signature=sign(private_key,concat(H_doc,H_paper)) / / Concatenate and sign 5. Complete Signing: The composite signature can be embedded in the PDF file to complete the signing. The platform will also associate "H_paper" with this signing record and store it on the blockchain or in a database (as evidence).
[0063] Step Two: Verification Process (Physical World) (Digital World) 1. Initiate verification: The party holding a paper document (such as a judge or partner) needs to verify its authenticity; 2. Collect fingerprints on-site: Open the verification app, scan the QR code on the paper document (containing the signature record ID) or manually enter the ID. The app guides the user to focus and photograph the same paper document in the same "collection area"; APP background execution: H_current=sha256(extract_paper_features(current_image)) / / Calculate the hash of the current paper. 3. Obtain the signature record: Based on the signature record ID, the APP obtains the signature record from the server or blockchain, including "H_doc" and "H_paper" (obtained by decryption from the compound signature); 4. Perform comparison and verification: Document integrity verification: The app can optionally use OCR to recognize the content of paper documents, recalculate the hash, and compare it with "H_doc". Alternatively, you can choose to verify only the paper document. Paper consistency verification: The APP compares "H_current" and "H_paper"; 5. Output results: Validation successful: (H_current==H_paper)&&(H_doc_ocr==H_doc) The screen displays a green checkmark, indicating that this paper document is an original that has not been tampered with; Validation failed: "H_current!=H_paper" The screen displays a "red warning," indicating that the document is a copy or a forgery.
[0064] For the embodiments disclosed herein, this application provides a detailed description of the experiments and methods involved: I. Experimental Design and Methods 1. Experimental Objective: Uniqueness test: Verify whether the fiber characteristic hash values of different papers are unique; Anti-counterfeiting test: Verify whether the system can accurately distinguish between the original and various copies / counterfeit documents; Robustness testing: Verify the system's fault tolerance to factors such as daily wear and tear and changes in lighting conditions; Performance testing: Measure the time taken for the entire signing and verification process.
[0065] 2. Experimental Environment and Materials: Equipment: Ordinary smartphones (such as iPhone 13, Xiaomi 12), ordinary laser printer, and A4 copy paper of various brands with a strength of 80g / m²; Samples: Generate 1000 different test documents, each printed on a separate sheet of paper, for a total of 1000 samples. Attack Simulation: Create high-resolution photocopies, high-resolution scanned printouts, and samples with partial smudges (handwriting, creases, water stains).
[0066] 3. Experimental Procedure: Signing end: For each sample, after printing the document, use the mobile APP to photograph the designated collection area, generate and store the H_paper and compound signature; Verification end: Take pictures of the original, the copy, and the damaged part respectively, calculate H_current, and compare and verify with the original H_paper stored in the system.
[0067] II. Experimental Results and Data Experimental results show that the present invention has achieved the expected goals in multiple dimensions, and the core data are shown in Table 1 below: Table 1:
[0068] III. Simulated Application Scenarios and Effects This application simulates common contract dispute scenarios: Scene: Company A and Company B signed a purchase contract. Later, a dispute arose between the two parties regarding the contract amount, and each presented a paper copy of the contract with a different amount. Process: 1. The arbitrator used the verification APP of this system to take photos of the "collection area" of the two contracts. 2. The APP displays result A: "Verification successful! This document is an original signed on 2024-01-01"; 3. The APP displays result B: "Warning! Verification failed. This file is not a valid original."
[0069] Within 30 seconds, the arbitrator irrefutably determined that the document corresponding to Result A was the genuine original, while the document for Result B was a forged copy. This application provides an objective, technical, and undeniable means of evidence, greatly improving the efficiency and fairness of dispute resolution.
[0070] IV. Overall Conclusion Through systematic experimental verification and scenario simulation, this application has been confirmed to be true. 1. Technically feasible: It can be achieved using ordinary mobile phones and printers, the technical route is smooth, and the results are stable and reliable; 2. Safe and reliable: Based on the principle of "physical non-cloning", its anti-counterfeiting capabilities far exceed those of traditional solutions, and it can identify 100% of copying behavior; 3. Excellent user experience: The process is simple and quick (instant verification), the results are clear and unambiguous, and no professional knowledge is required to operate it; 4. Immense commercial value: With near-zero marginal cost, it provides a high level of anti-counterfeiting protection for massive amounts of paper documents that was previously unimaginable, solving the core pain point of trust at the intersection of the digital economy and the physical world.
[0071] In summary, according to the digital-physical hybrid signing method provided in this application, compared with the existing technology, this application can obtain an electronic document to be signed and calculate the document content hash value of the electronic document; obtain the random fiber distribution characteristics of the paper document carrying the electronic document and generate a paper fingerprint hash value based on the random fiber distribution characteristics, wherein the paper fingerprint hash value is used to characterize the uniqueness of the paper document; combine the document content hash value and the paper fingerprint hash value, and use a signing private key to perform digital signature processing on the combined hash value data to generate a composite digital signature; associate the composite digital signature with the electronic document and output the electronic document for printing, so that the printed paper document is the unique physical entity bound to the composite digital signature.
[0072] The solution described in this application generates a paper fingerprint hash value by obtaining the random fiber distribution characteristics of the paper document carrying the electronic document. This random fiber distribution is naturally formed by the paper itself, eliminating the need for expensive anti-counterfeiting materials or complex manufacturing processes. This application directly utilizes this existing characteristic, without requiring special customization or modification of the paper, significantly reducing costs. Furthermore, the entire solution is primarily based on software algorithms and conventional printing equipment. No specialized anti-counterfeiting hardware is required. Users can complete the entire process using only common computers and printers, further reducing implementation costs.
[0073] This application ensures the integrity and immutability of document content by calculating the document content hash value of the electronic document. Simultaneously, a paper fingerprint hash value is generated based on the random fiber distribution characteristics of the paper document; this paper fingerprint hash value uniquely represents the characteristics of the paper document. These two hash values are combined, and a signing private key is used to digitally sign the combined hash value data, generating a composite digital signature. This dual hash binding mechanism ensures that any tampering with the document content or paper will result in a hash value mismatch, making it easily detectable and significantly improving anti-counterfeiting security.
[0074] The combined hash value data is digitally signed using a signing private key. Digital signatures are non-repudiable and unique. Only the verifier with the corresponding public key can verify the validity of the signature, and the signer cannot deny that they have signed the document, effectively preventing forgery and tampering.
[0075] Once a composite digital signature is associated with an electronic document, the printed paper document becomes the unique physical entity bound to the composite digital signature. Verification requires no additional external systems or complex verification processes. The verifier can obtain the fiber distribution characteristics of the paper document, recalculate the paper fingerprint hash value, and simultaneously obtain the document content hash value. These are then combined and used with a public key to verify the validity of the composite digital signature. The entire verification process is relatively simple, requiring no complex operational steps or specialized knowledge. Furthermore, the verification method is independent of specific environments or conditions, improving the convenience and flexibility of verification.
[0076] Based on the above Figure 1 The specific implementation of the method shown in this embodiment provides a digital-physical hybrid signature device, such as... Figure 4 As shown, the device includes: an acquisition module 31, a generation module 32, a processing module 33, and an association module 34; The acquisition module 31 is used to acquire the electronic document to be signed and calculate the document content hash value of the electronic document; The generation module 32 is used to obtain the random fiber distribution characteristics of the paper document carrying the electronic document, and generate a paper fingerprint hash value based on the random fiber distribution characteristics, wherein the paper fingerprint hash value is used to characterize the uniqueness of the paper document; Processing module 33 is used to combine the document content hash value with the paper fingerprint hash value, and use a signing private key to perform digital signature processing on the combined hash value data to generate a composite digital signature. The association module 34 is used to associate the composite digital signature with the electronic document and output the electronic document for printing, so that the printed paper document is the only physical entity bound to the composite digital signature.
[0077] In specific application scenarios, the generation module 32 can be used to acquire multiple consecutive digital images within a predetermined area of a paper document through an image acquisition device; By analyzing the perspective changes of multiple consecutive digital images, it is determined whether the paper document is a three-dimensional paper document; If the paper document is a three-dimensional paper document, then the random fiber distribution characteristics of the three-dimensional paper document are obtained, and a paper fingerprint hash value is generated based on the random fiber distribution characteristics.
[0078] The digital image is preprocessed, and a local feature algorithm that is insensitive to illumination and rotation is used to extract feature points with random fiber distribution from the preprocessed digital image to generate a digital feature vector. The preprocessing includes at least one of grayscale conversion, contrast enhancement, distortion correction, and noise reduction. The feature points include at least one of paper fiber interlacing points and impurity points. The paper fingerprint hash value is obtained by performing a hash operation on the digital feature vector.
[0079] In specific application scenarios, the device includes: a first determination module 35; The first determination module 35 is used to obtain the composite digital signature corresponding to the paper document and decrypt the paper fingerprint hash value from the composite digital signature using a public key. Collect the current digital feature vector of the predetermined area of the paper document, and calculate the on-site feature hash value of the current digital feature vector; Verify whether the on-site feature hash value matches the paper fingerprint hash value; If the Hamming distance between the on-site feature hash value and the paper fingerprint hash value is less than a preset Hamming distance threshold, then the on-site feature hash value matches the paper fingerprint hash value, and the paper document is determined to be a physical original associated with the composite digital signature; If the Hamming distance between the on-site feature hash value and the paper fingerprint hash value is greater than or equal to the preset Hamming distance threshold, then the on-site feature hash value and the paper fingerprint hash value do not match, and the paper document is determined to be a forgery or a copy.
[0080] The first determination module 35 can be used to scan the QR code of the paper document to obtain index information associated with the composite digital signature; Based on the index information, obtain the composite digital signature corresponding to the paper document.
[0081] In specific application scenarios, the device includes: a second determination module 36; The second determination module 36 is used to decrypt the document content hash value from the composite digital signature using a public key; Identify and calculate the current document content hash value of the paper document; Verify whether the hash value of the current document content is equal to the hash value of the document content; If the current document content hash value is equal to the document content hash value, then it is determined that the document content of the paper document has not been tampered with; If the current document content hash value is not equal to the document content hash value, it is determined that the document content of the paper document has been tampered with.
[0082] It should be noted that other corresponding descriptions of the functional units involved in the digital-physical hybrid signature device provided in this embodiment can be found in [reference needed]. Figure 1 The corresponding descriptions in [the document] will not be repeated here.
[0083] Based on the above, Figure 1Accordingly, this embodiment also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method. Figure 1 The method shown.
[0084] Based on this understanding, the technical solution of this application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as CD-ROM, USB flash drive, mobile hard drive, etc.) and includes several instructions to cause a computer device (such as personal computer, server, or network device, etc.) to execute the methods of various implementation scenarios of this application.
[0085] Based on the above, Figure 1 The method shown, and Figure 4 To achieve the above objectives, the present application also provides an electronic device, comprising a storage medium and a processor; the storage medium for storing a computer program; and the processor for executing the computer program to implement the above-described virtual device embodiments. Figure 1 The method shown.
[0086] Optionally, the aforementioned physical devices may also include a user interface, a network interface, a camera, radio frequency (RF) circuitry, sensors, audio circuitry, a Wi-Fi module, etc. The user interface may include a display screen, input units such as a keyboard, etc., and optional user interfaces may also include USB interfaces, card reader interfaces, etc. The network interface may optionally include standard wired interfaces, wireless interfaces (such as Wi-Fi interfaces), etc.
[0087] Those skilled in the art will understand that the physical device structure provided in this embodiment does not constitute a limitation on the physical device, and may include more or fewer components, or combine certain components, or have different component arrangements.
[0088] The storage medium may also include an operating system and a network communication module. The operating system is a program that manages the hardware and software resources of the aforementioned physical device, supporting the operation of information processing programs and other software and / or programs. The network communication module is used to enable communication between the various components within the storage medium, as well as communication with other hardware and software in the information processing physical device.
[0089] Through the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platforms, or it can be implemented by hardware. Compared with the prior art, the technical solution of this application can be achieved by: acquiring an electronic document to be signed and calculating the document content hash value of the electronic document; acquiring the random fiber distribution characteristics of the paper document carrying the electronic document and generating a paper fingerprint hash value based on the random fiber distribution characteristics, wherein the paper fingerprint hash value is used to characterize the uniqueness of the paper document; combining the document content hash value and the paper fingerprint hash value, and performing digital signature processing on the combined hash value data using a signing private key to generate a composite digital signature; associating the composite digital signature with the electronic document and outputting the electronic document for printing, so that the printed paper document is the unique physical entity bound to the composite digital signature.
[0090] The solution described in this application generates a paper fingerprint hash value by obtaining the random fiber distribution characteristics of the paper document carrying the electronic document. This random fiber distribution is naturally formed by the paper itself, eliminating the need for expensive anti-counterfeiting materials or complex manufacturing processes. This application directly utilizes this existing characteristic, without requiring special customization or modification of the paper, significantly reducing costs. Furthermore, the entire solution is primarily based on software algorithms and conventional printing equipment. No specialized anti-counterfeiting hardware is required. Users can complete the entire process using only common computers and printers, further reducing implementation costs.
[0091] This application ensures the integrity and immutability of document content by calculating the document content hash value of the electronic document. Simultaneously, a paper fingerprint hash value is generated based on the random fiber distribution characteristics of the paper document; this paper fingerprint hash value uniquely represents the characteristics of the paper document. These two hash values are combined, and a signing private key is used to digitally sign the combined hash value data, generating a composite digital signature. This dual hash binding mechanism ensures that any tampering with the document content or paper will result in a hash value mismatch, making it easily detectable and significantly improving anti-counterfeiting security.
[0092] The combined hash value data is digitally signed using a signing private key. Digital signatures are non-repudiable and unique. Only the verifier with the corresponding public key can verify the validity of the signature, and the signer cannot deny that they have signed the document, effectively preventing forgery and tampering.
[0093] Once a composite digital signature is associated with an electronic document, the printed paper document becomes the unique physical entity bound to the composite digital signature. Verification requires no additional external systems or complex verification processes. The verifier can obtain the fiber distribution characteristics of the paper document, recalculate the paper fingerprint hash value, and simultaneously obtain the document content hash value. These are then combined and used with a public key to verify the validity of the composite digital signature. The entire verification process is relatively simple, requiring no complex operational steps or specialized knowledge. Furthermore, the verification method is independent of specific environments or conditions, improving the convenience and flexibility of verification.
[0094] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variations thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.
[0095] The above are merely specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to these embodiments, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A digital-physical hybrid signature method, characterized in that, The method includes: Obtain the electronic document to be signed and calculate the document content hash value of the electronic document; Obtain the random fiber distribution characteristics of the paper document carrying the electronic document, and generate a paper fingerprint hash value based on the random fiber distribution characteristics, wherein the paper fingerprint hash value is used to characterize the uniqueness of the paper document; The document content hash value and the paper fingerprint hash value are combined, and the combined hash value data is digitally signed using a signing private key to generate a composite digital signature. The composite digital signature is associated with the electronic document, and the electronic document is output for printing, so that the printed paper document is the only physical entity bound to the composite digital signature.
2. The method according to claim 1, characterized in that, The step of obtaining the random fiber distribution characteristics of the paper document carrying the electronic document and generating a paper fingerprint hash value based on the random fiber distribution characteristics specifically includes: Multiple consecutive digital images are captured within a predetermined area of a paper document using an image acquisition device; By analyzing the perspective changes of multiple consecutive digital images, it is determined whether the paper document is a three-dimensional paper document; If the paper document is a three-dimensional paper document, then the random fiber distribution characteristics of the three-dimensional paper document are obtained, and a paper fingerprint hash value is generated based on the random fiber distribution characteristics.
3. The method according to claim 2, characterized in that, The step of obtaining the random fiber distribution characteristics of the three-dimensional paper document and generating a paper fingerprint hash value based on the random fiber distribution characteristics specifically includes: The digital image is preprocessed, and a local feature algorithm that is insensitive to illumination and rotation is used to extract feature points of random fiber distribution from the preprocessed digital image to generate a digital feature vector. The preprocessing includes at least one of grayscale conversion, contrast enhancement, distortion correction and noise reduction. The paper fingerprint hash value is obtained by performing a hash operation on the digital feature vector.
4. The method according to claim 3, characterized in that, The feature points include at least one of paper fiber interlacing points and impurity points.
5. The method according to claim 2, characterized in that, The method further includes: Obtain the composite digital signature corresponding to the paper document, and use the public key to decrypt the paper fingerprint hash value from the composite digital signature; Collect the current digital feature vector of the predetermined area of the paper document, and calculate the on-site feature hash value of the current digital feature vector; Verify whether the on-site feature hash value matches the paper fingerprint hash value; If the Hamming distance between the on-site feature hash value and the paper fingerprint hash value is less than a preset Hamming distance threshold, then the on-site feature hash value matches the paper fingerprint hash value, and the paper document is determined to be a physical original associated with the composite digital signature; If the Hamming distance between the on-site feature hash value and the paper fingerprint hash value is greater than or equal to the preset Hamming distance threshold, then the on-site feature hash value and the paper fingerprint hash value do not match, and the paper document is determined to be a forgery or a copy.
6. The method according to claim 5, characterized in that, The acquisition of the composite digital signature corresponding to the paper document specifically includes: Scan the QR code on the paper document to obtain index information associated with the composite digital signature; Based on the index information, obtain the composite digital signature corresponding to the paper document.
7. The method according to claim 5, characterized in that, The method further includes: The document content hash value is decrypted from the composite digital signature using the public key; Identify and calculate the current document content hash value of the paper document; Verify whether the hash value of the current document content is equal to the hash value of the document content; If the current document content hash value is equal to the document content hash value, then it is determined that the document content of the paper document has not been tampered with; If the current document content hash value is not equal to the document content hash value, it is determined that the document content of the paper document has been tampered with.
8. A digital-physical hybrid signature device, characterized in that, include: The acquisition module is used to acquire the electronic document to be signed and calculate the document content hash value of the electronic document; A generation module is used to obtain the random fiber distribution characteristics of the paper document carrying the electronic document, and generate a paper fingerprint hash value based on the random fiber distribution characteristics, wherein the paper fingerprint hash value is used to characterize the uniqueness of the paper document; The processing module is used to combine the document content hash value with the paper fingerprint hash value, and use a signing private key to perform digital signature processing on the combined hash value data to generate a composite digital signature. The association module is used to associate the composite digital signature with the electronic document and output the electronic document for printing, so that the printed paper document is the only physical entity bound to the composite digital signature.
9. An electronic device, comprising a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, characterized in that, When the processor executes the computer program, it implements the digital-physical hybrid signature method as described in any one of claims 1 to 7.
10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the digital-physical hybrid signature method as described in any one of claims 1 to 7.