WO2019095172A1

WO2019095172A1 - Qr code generating and decoding method and apparatus in qr code copying process

Info

Publication number: WO2019095172A1
Application number: PCT/CN2017/111213
Authority: WO
Inventors: 陈昌盛; 谢宁; 罗钢
Original assignee: 深圳大学
Priority date: 2017-11-15
Filing date: 2017-11-15
Publication date: 2019-05-23

Abstract

A generating and decoding method in a QR code copying process. In combination with a QR code communication channel model and physical device features in a scanning-printing process, after original QR code information is encoded and modulated and before the information enters a communication channel for transmission, authentication information is superposed onto the original information in the form of artificial noise to be transmitted into the communication channel together; the authentication information can be extracted from a receiving terminal by comparing and analyzing a QR code subjected to image restoration and the QR code subjected to noise removal; the authentication information is decoded by using an agreed key and a decoding technology. Therefore, the QR code is authenticated and the security of the QR code in a communication process is improved.

Description

Two-dimensional code generation and decoding method and device in two-dimensional code copying process

Technical field

The invention relates to a method and a device for generating and decoding in a two-dimensional code copying process.

Background technique

In recent years, QR code has become a universal information carrier, which has the characteristics of large amount of stored information, wide application range, strong anti-noise and anti-interference ability, and is popularized with the promotion of smart phones, especially in identity verification. Network transmission, e-Cert and bills have been widely used. However, there are many loopholes in the generation, copying, transmission, and receiving of QR codes, which are easy to be cracked, counterfeited, and abused. Therefore, how to improve the security of QR codes, especially in the process of copying Sex has become the focus of current attention. Nowadays, the generation and replication of QR codes mainly have the following methods to improve security.

Control the generation and copying of QR codes using special printed materials or processes. The special printed material in the printing process, such as holographic materials and polymeric liquid crystal materials having unique optical characteristics, can be used to print the two-dimensional code to prevent it from being copied. Special printing inks can also be applied to the printing of two-dimensional codes. For example, ultraviolet fluorescent inks make the printed two-dimensional code invisible under visible light to prevent it from being copied. Special production processes can also be used to enhance the security of QR codes. For example, special halftone printing technology can generate two-dimensional codes hidden under visible light.

The encryption algorithm and the security protocol are used to control the generation and reading of the two-dimensional code. An asymmetric key encryption algorithm (for example, RSA algorithm) and a PKI public key encryption system can be used to control the generation of a two-dimensional code and verify the authenticity of its information, such as Chinese patent CN201110054417.2 and CN201410520353.4 in two-dimensional code transmission or An asymmetric key encryption algorithm is used in the production process, and Wang et al. applied such encryption-protected system to the construction of the anti-counterfeiting platform in Using Modified Digital Halftoning Technique to Design Invisible 2D Barcode by Infrared Detection. The Chaotic Equation can be used to generate the QR code identity number to ensure its uniqueness and the random string cannot be copied in batches, thus effectively controlling the generation of the QR code. Similarly, AuthPaper The ECDSA digital signature algorithm is applied within the system to prevent document counterfeiters from tampering with the content. In addition to the encryption algorithm, the researchers also proposed some security protocols based on the communication architecture to enhance the security of the displayed two-dimensional code. For example, the researcher proposed a communication protocol called "all or nothing" based on the duplex communication system of the mobile device front camera device and the display screen. Only when the receiver can acquire the transmitted and received signals at the same time can the information of the two-dimensional code in the channel be decoded, thereby enhancing the confidentiality of the information.

Use digital watermarking technology to control the generation of QR codes. The digital watermarking technique can embed information related to the two-dimensional code in the two-dimensional code image. For example, directly using DCT and DFT to decompose the image frequency information of the two-dimensional code, it is possible to embed watermark information that is not easily perceptible to the naked eye. After the two-dimensional code image is taken, it can be decoded and the authenticity of the digital watermark information can be evaluated at the same time. Similarly, digital watermarks can also be stored in the DWT domain. For example, Chinese patent CN201710187615.3 embeds watermark information in the logo image of the two-dimensional code, Two-Level QR Code for Private Message Sharing and Document Authenticatio by Tkachenko et al. and Towards a Realistic Channel Model for Security Analysis of Authentication by Baras et al. Using Graphical Codes has proposed a method to ensure more robust watermark information. Using the information redundancy of the two-dimensional code, the overall brightness of some modules is modified to store the digital signature of the two-dimensional code content. Tkachenko et al. comprehensively consider the robustness and capacity of watermark information in Centrality Bias Measure for High Density QR Code Module Recognition, and use the distortion tolerance of each module in the process of decoding QR code to modify the module's style to store watermark information. .

The generation and copying of the two-dimensional code is controlled using a pattern pattern having a copy detection feature or a physical non-cloning feature. For the sake of decoding stability, the conventional two-dimensional code is composed of a large black and white block unit. However, this design is easy to copy. Some pattern patterns with more detail features can be used in the design of two-dimensional codes to resist the most direct scan-print form reproduction. Dirik et al.'s Copy Detection Pattern-based Document Protection for Variable Media and Gaubatz et al's Distortion Metrics for Predicting Authentication Functionality of Printed Security Deterrents use high-density black-and-white cells to form graphics in copy detection, and apply the same in the detection process. The number normal distribution is used as a key model for the print-scan channel. In addition to black and white binary images, grayscale images can also be used in copy detection patterns. Wherein, the decision of copy detection may be based on a variation feature of the grayscale image in the print-scan channel, mainly including high frequency features of the image, such as Gaubatz et al. extract a feature set based on the sharpness of the image in the Towards a Feature Set for Robust Printing-Imaging Cycle Device Identification using Structured Printed Markings. Compared to grayscale images, the color pattern contains information on four channels of CMYK. After copying, the characteristics of the colors (color mean, variance, entropy, etc. within the module) will make a significant difference. In addition to the above detailed pattern features, the physical unclonable function in the printed document is also used to identify illegal copying of the printed document. The Physical Unclonable Function (PUF) is a random change produced by printing equipment and paper. Its features are easy to extract and analyze but are not easily copied and forged. For example, Wong et al.'s Counterfeit Detection using Paper PUF and Mobile Cameras and Khanna et al.'s A Survey of Forensic Characterization Methods for Physical Devices, mentioned random variations in print toner and paper, and Chiang et al., Printer and Scanner Forensics The microscopic roughness of the paper.

The ciphertext is stored by using specific information, for example, the Chinese patent CN201110113881.X stores the ciphertext separately as the error correction code information, avoids the data area of the two-dimensional code, and has an independent ciphertext transmission function; the Chinese patent CN201610945368.4 encrypts the information. The storage is the mask information with the identification function, and the binary operation related to the information of the two-dimensional code, thereby covering the data of the original two-dimensional code, thereby improving the security of transmission; US Patent US201514662377A converts the encrypted information into picture information. And embedded in the two-dimensional code, combined with the two-dimensional code graphic to become a pair of pictures for transmission.

The above types of methods can enhance the security of the two-dimensional code to varying degrees, but also bring some problems.

On the one hand, it reduces the advantage of the two-dimensional code in versatility. Making a two-dimensional code with a special printing material or process can strengthen the control of the generation process to resist the illegal copying of the two-dimensional code, but inevitably reduces the versatility of the two-dimensional code (adding the two-dimensional code Production costs and dependence on special equipment). Compared with similar technologies (such as RFID and smart sensors), the main advantages of QR codes are their extremely low cost and flexibility that does not depend on special hardware. Therefore, such methods based on special printed materials or processes will greatly reduce the competitiveness of two-dimensional codes for large-scale applications in the Internet of Things.

On the one hand, increase the complexity of use. Compared with the traditional two-dimensional code, the introduction of algorithms based on encryption and digital watermarking or security protocols can control the unauthorized generation of the two-dimensional code and The illegal tampering of the data, but increased the complexity of the system. Taking the encryption and watermarking algorithms as an example, the complexity is mainly reflected in the following two aspects: First, in the process of generating and controlling the two-dimensional code by using the asymmetric encryption algorithm and the digital signature technology, the public key infrastructure needs to be arranged (Public) Key Infrastructure, PKI). The security of each user's private key must be guaranteed and the corresponding public key distributed through a secure communication channel. Secondly, in the process of using the information, the steps of decrypting or extracting the two-dimensional code are additionally added.

On the one hand, it is impossible to effectively resolve the contradiction between resisting illegal copying and universal applicability. Most importantly, even if the two-dimensional code applies a copy detection pattern and a physical unclonable function, or the above-mentioned security (encryption and digital watermark) algorithm, it is difficult to prevent the counterfeiter from copying the two-dimensional code under the system framework of the Internet of Things. Image features extracted based on physical unclonable functions relate to details in the printed output image. In order to accurately capture such features, there is a certain limit to the verification environment of the two-dimensional code, which does not meet the general applicability of the Internet of Things. For example, placing the verified document in a relatively fixed distance and lighting environment. On the other hand, since the above security algorithm only guarantees the reliability of the information in the two-dimensional code in terms of information encryption, and cannot change the visibility of the information in the two-dimensional code, it is also difficult to effectively resist illegal copying. In addition, since the copy detection pattern usually determines the authenticity of the image based on the attenuation of the high frequency information, the copying device (high-precision scanner, copying machine, etc.) used by the attacker tends to have higher resolution and high-frequency information. The reservation is more complete. Therefore, it is difficult to prevent the counterfeiter from copying it while ensuring the general type of the verification device.

On the one hand, it encroaches on the storage and operation space of other data. In particular, occupying the storage space of the two-dimensional code itself, since the amount of data carried by the two-dimensional code is constant, the encrypted information or the encrypted data occupying the storage space of the two-dimensional code means that the number of codes of the two-dimensional code is reduced, and the number of codes is reduced. The application range of the dimension code. In addition, other information spaces also need sufficient information to effectively complete data processing, such as error correction information areas, etc., occupying these data areas will result in insufficient control of these control information, thereby indirectly reducing the code of the two-dimensional code. Quantity.

In summary, in recent years, people have realized the problems of QR code generation and copy control, and proposed some solutions, and brought effective control to the generation control. However, the comprehensive performance of these methods in ensuring the uniqueness of the two-dimensional code, that is, resisting illegal copying, needs to be further improved. In the face of increasingly serious product counterfeiting and relatively preliminary two-dimensional code traceability anti-counterfeiting system framework, it is necessary to actively explore and improve the security of QR code to resist non- New theory and technical solutions for legal reproduction.

Summary of the invention

Since the use of two-dimensional codes by people at this stage is not limited to the addition of public numbers and the payment of commodity fees, people are paying more and more attention to the security of two-dimensional codes while widely used. In order to improve the security of the two-dimensional code in the copying process, the present invention proposes the following technical solutions.

A first aspect of the present invention relates to a method for generating a two-dimensional code in a two-dimensional code copying process, the steps of which are: converting original information into a bit stream by an encoding method; converting the bit stream into an image of the original information a gray value; loading the authentication information, and generating an image gray value of the authentication information; superimposing the image gray value of the authentication information on the image gray value of the original data to form a superimposed gray image Adding a finder pattern to the superimposed image gradation to generate a two-dimensional code.

In the two-dimensional code generating method according to the present invention, the loading authentication information includes the authentication information as authentication information having a white noise characteristic.

In the two-dimensional code generating method according to the present invention, the generated two-dimensional code is mixed with channel noise during transmission.

In the two-dimensional code generating method of the present invention, the superimposing the image gradation value of the authentication information onto the image gradation value of the original data includes the image gradation value of the original information and the The image gray value of the authentication information is superimposed in a center-aligned manner.

In the two-dimensional code generating method of the present invention, the superimposing the image gradation value of the authentication information onto the image gradation value of the original data includes the image gradation value of the original information and the The superimposed position of the image gradation value of the authentication information may be in a dispersed form.

In the two-dimensional code generating method of the present invention, the superimposing the image gradation value of the authentication information onto the image gradation value of the original data includes the image gradation value of the original information and the The superimposed position of the image gradation value of the authentication information is set by the mutual understanding, or by mutual agreement, or by mutual agreement, and is not disclosed.

In the two-dimensional code generating method of the present invention, the superimposing the image gradation value of the authentication information onto the image gradation value of the original data includes, the original information The image gradation value and the image gradation value of the authentication information are superimposed in a specified pattern.

In the two-dimensional code generating method of the present invention, the superimposing the image gradation value of the authentication information onto the image gradation value of the original data includes the image gradation value of the original information and the The image gradation value of the authentication information is superimposed with a specified gradation value.

A second aspect of the present invention relates to a two-dimensional code decoding method in a two-dimensional code copying process, the steps of which are as follows: acquiring a two-dimensional code; and acquiring the acquired two-dimensional code image, and performing an image restoration step to restore the second The shape grayscale image is subjected to shape distortion, color and/or brightness distortion in the communication channel to obtain a first grayscale image of the two-dimensional code; and the first grayscale image is generated according to the signal in the two-dimensional code generation step Demodulating the modulation method, removing the channel noise and the authentication information, obtaining a second grayscale image of the two-dimensional code, obtaining the authentication information by using the first grayscale image and the second grayscale image; The second grayscale image is subjected to a source decoding operation to obtain a noiseless original bitstream; the noiseless original bit data is converted into a noiseless two-dimensional code grayscale value by secondary encoding and secondary modulation.

In the two-dimensional code decoding method according to the present invention, the first grayscale image of the two-dimensional code is demodulated according to a signal modulation method in the two-dimensional code generating step to remove channel noise and authentication information, and further includes the following steps: The error introduced by the channel is corrected by decoding.

In the method for decoding a two-dimensional code according to the present invention, the method further includes the following steps: performing a difference operation between the first grayscale image before decoding and the second grayscale image after decoding to obtain the channel noise. And the authentication information.

In the two-dimensional code decoding method according to the present invention, the method further includes the step of separating the authentication information from the channel noise by using a BCH decoding method.

A third aspect of the present invention relates to a two-dimensional code generating apparatus in a two-dimensional code copying process, including: a bit stream generating module: converting original information into a bit stream by an encoding method; and an image converting module: the bit stream Converting to the image gray value of the original information; the authentication information loading module: loading the authentication information, and generating the image gray value of the authentication information; and the image superimposing module: superimposing the image gray value of the authentication information to the The superimposed grayscale image is formed on the image gray value of the original data; the two-dimensional code generating module adds a finder pattern to the superimposed image grayscale to generate a two-dimensional code.

A fourth aspect of the present invention relates to a two-dimensional code decoding apparatus in a two-dimensional code copying process, comprising: an acquiring module: acquiring a two-dimensional code; and recovering an image module: the acquired two-dimensional code image is passed through an image a recovery step of restoring the grayscale image of the two-dimensional code in a communication letter Distortion of shape, color and/or brightness received in the track to obtain a first grayscale image of the two-dimensional code; demodulating the first grayscale image according to a signal modulation method in the two-dimensional code generating step to remove channel noise And the authentication information, obtaining a second grayscale image of the two-dimensional code, obtaining the authentication information by using the first grayscale image and the second grayscale image; and decoding the demodulation module: the demodulated second gray The degree image is subjected to a source decoding operation to obtain a noiseless original bit stream; the secondary code modulation module converts the noiseless original bit data into a noiseless two-dimensional code gray value by secondary encoding and secondary modulation.

The two-dimensional code decoding apparatus according to the present invention further includes a noise separation module that separates the authentication information from the channel noise by using a BCH decoding method.

The invention combines the communication channel model of the two-dimensional code and the characteristics of the physical device (scanning and printing device) in the scanning-printing process, and after the original two-dimensional code information is encoded and modulated, before the communication channel is transmitted, the authentication information is artificially The form of the noise is superimposed on the original information and transmitted into the communication channel together. By comparing and analyzing the two-dimensional code after the image is repaired and the two-dimensional code after the noise is removed, the authentication information can be extracted from the receiving end, and the agreed secret is used. The key and decoding technology completes the decoding of the authentication information, thereby completing the authentication of the two-dimensional code and improving its security in the communication process.

DRAWINGS

1 is a schematic block diagram showing generation and decoding of a two-dimensional code in a two-dimensional code copying process of the present invention;

2 is a flow chart showing a method of generating a two-dimensional code in the process of copying a two-dimensional code of the present invention;

3 is a flow chart showing a two-dimensional code decoding method in the two-dimensional code copying process of the present invention;

4 is a structural diagram showing a two-dimensional code generating apparatus in a two-dimensional code copying process of the present invention;

Figure 5 is a block diagram showing a two-dimensional code decoding apparatus in the two-dimensional code copying process of the present invention.

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following In the description, the same components are denoted by the same reference numerals, and the description thereof will not be repeated. In addition, the drawings are merely schematic views, and the ratio of the dimensions of the components to each other or the shape of the components may be different from the actual ones.

1 is a schematic block diagram showing two-dimensional code generation and decoding in a two-dimensional code copying process of the present invention; FIG. 2 is a flow chart showing a two-dimensional code generating method in a two-dimensional code copying process of the present invention; .

In the present embodiment, as shown in FIG. 1, the two-dimensional code generation method and the decoding principle in the two-dimensional code copying process include encoding, modulation, authentication, de-authentication, demodulation, decoding, and the like, and the figure also shows Generate and acquire channels in the process.

In this embodiment, as shown in FIG. 2, the two-dimensional code generating method and the decoding method in the two-dimensional code copying process may include the following steps: a bit stream generating step 201: converting the original information into a bit stream by using an encoding method. In this embodiment, the original information input by the user may have many types, including characters, a web address, a picture, a business card, and the like, and the above information may be converted into a bit stream by encoding. In order to further compress the data and improve the transmission efficiency, the bit stream can be processed by using source coding, and channel coding is also needed to improve the reliability of data transmission.

In the present embodiment, an image conversion step 202 is further included: converting the bit stream into an image gray value of the original information. The authentication information loading step 203: loading the authentication information and generating an image gray value of the authentication information.

In this embodiment, the authentication information may adopt various types of methods, such as a common ciphertext form, watermark information, and the like, and may also generate noise with white noise characteristics, especially white noise with statistically independent characteristics, thereby In this way, not only can the hidden authentication information be added to the original data with minimal interference, but also the acquisition party can separate the authentication information.

In the embodiment, the image superimposing step 204 is further included: superimposing the image gradation value of the authentication information on the image gradation value of the original data to form the superimposed gradation image. The process of loading the authentication information is generally performed by superposition, or other types of operations, such as XOR, same OR, phase, and splicing operations. The image gradation value of the authentication information is superimposed on the image gradation value of the original data to form a superimposed gradation image.

In the present embodiment, a two-dimensional code generating step 205 is further included: a finder pattern is added next to the superimposed image gradation to generate a two-dimensional code.

In the present embodiment, as shown in FIG. 1, the channel is schematic, and as a two-dimensional code, the data channel that passes through is generated from acquisition to acquisition. Typically, such channels are transport type, but can also represent the process between generation and acquisition. For example, after the two-dimensional code is generated, the user presents the two-dimensional code on the paper medium by printing, for example, on the billboard, and other authorized users can obtain the two-dimensional code by shooting or scanning. →Printing→Scanning process can be considered as passing the channel.

In the present embodiment, the two-dimensional code passing through the channel inevitably incorporates channel noise, which may include light, shading, shading, refraction, distortion, blurring, sharpening, missing, and the like. Generally, the two-dimensional code itself has strong error correction capability, but after acquiring the two-dimensional code, the noise on the image can be removed by filtering, or modulation, or demodulation, and the noise is often channel noise.

In the present embodiment, in the process of loading the authentication information, the loading may be performed by superimposing. The present invention considers selecting a superimposed position, selecting a superimposed angle, or selecting another superimposing manner as a way to avoid illegal copying. For example, the following methods can be used for superposition.

In the present embodiment, from the position of the superposition, the image gradation value of the original information and the image gradation value of the authentication information may be superimposed in a center-aligned manner; the authentication information may be dispersed while being in the image The corners are superimposed; the authentication information can also be lengthened and superimposed along the edges of the QR code. In particular, the location of the overlay may not be disclosed to the public, and the location of the overlay may be set up and obtained by mutual agreement or by mutual agreement, thereby further preventing malicious third parties from copying and improving the security of the authentication information. .

In the present embodiment, from the viewpoint of the superimposed pattern, the authentication information may be formed into a designated pattern and then superimposed; or the superimposition may be performed according to the specified pattern. For example, the authentication information may be performed using a pattern of "rings". Superimposed. In particular, the superimposed pattern may not be disclosed to the public, and may be set up and acquired by using mutual understanding, or by mutual agreement, or by mutual agreement, thereby further preventing malicious third parties from copying and improving the security of the authentication information. .

Further, in the present embodiment, from the viewpoint of superimposition, it is possible to perform superimposition by rotating different angles after the pattern of the authentication information is determined. In particular, the angle of superposition may not be disclosed to the public, either by the parties, or by mutual agreement or by mutual agreement. The way to set up and obtain the angle of the overlay, thereby further avoiding the malicious third party to copy and improve the security of the authentication information.

In the present embodiment, from the other superimposing methods, the superimposition may be performed according to the specified gradation value, for example, superimposed on all modules having a gradation value of 100. In particular, the superimposed gradation may not be disclosed to the public, and the gradation of the superimposed gradation may be set by using the mutual understanding or the agreement between the two parties or the two parties to negotiate, thereby further preventing the malicious third party from copying and improving the authentication information. safety.

In addition, the above various superimposing possibilities may be further combined. For example, processing may be simultaneously considered from the superimposed position and the superimposed pattern. At this time, the superimposed position may select, for example, a corner, and the superimposed pattern may select, for example, a square, Round, or a specific pattern.

3 is a flow chart showing a two-dimensional code decoding method in the two-dimensional code copying process of the present invention.

In this embodiment, as shown in FIG. 3, after the two-dimensional code passes through the channel and is acquired, the two-dimensional code needs to be decoded, corresponding to the steps in the two-dimensional code generation process, and the decoding step includes: Step 208 is obtained to obtain a two-dimensional code. In the present embodiment, the two-dimensional code can be acquired in various possible ways. For example, by acquiring or scanning a two-dimensional code, a two-dimensional code picture can also be obtained by pre-storing, downloading, instant transmission, mail receiving, etc., and then extracting the two-dimensional code therein by using a picture processing program.

In this embodiment, a recovery step 209 is further included, and the acquired two-dimensional code image is subjected to an image restoration step to restore distortion, color, and/or brightness distortion of the two-dimensional code gray image received in the communication channel. The first grayscale image of the two-dimensional code.

In this embodiment, the method further includes the removing step 210: after the acquired two-dimensional code image is subjected to an image restoration step, the shape distortion, color, and/or brightness distortion received by the two-dimensional code gray image in the communication channel is restored. The first grayscale image of the two-dimensional code. In the middle of generating a two-dimensional code to obtain a two-dimensional code, the channel may cause some errors, which need to be corrected by decoding.

In this embodiment, the second grayscale image corresponds to the image data before the authentication information is loaded during the generation process, and therefore, the difference between the first grayscale image before decoding and the decoded grayscale image is performed. That is, channel noise and authentication information can be obtained. In this case, the BCH decoding method is required to separate the authentication information from the channel noise.

In this embodiment, a decoding and demodulating step 211 is further included: the demodulated second grayscale image is subjected to a source decoding operation to obtain a noiseless original bitstream.

In the present embodiment, a secondary decoding modulation step 212 is further included: converting the noiseless original bit data into a noiseless two-dimensional code gray value by secondary encoding and secondary modulation. Finally, the encryption and authentication of the information encoded by the user is completed by decoding the authentication information.

In order to implement the above method, the above steps are implemented by using corresponding functional modules and embedded in the device. Fig. 4 is a block diagram showing a two-dimensional code generating apparatus in the two-dimensional code copying process of the present invention.

As shown in FIG. 4, in the two-dimensional code generating apparatus in the two-dimensional code copying process according to the present embodiment, the method includes a bit stream generating module 301: converting the original information into a bit stream by using an encoding method; The original information can have many types, including characters, URLs, pictures, business cards, etc., and the above information can be converted into a bit stream by encoding. In order to further compress the data and improve the transmission efficiency, the bit stream can be processed by using source coding, and channel coding is also needed to improve the reliability of data transmission.

In the present embodiment, an image conversion module 302 is further included that converts the bit stream into an image gray value of the original information.

In this embodiment, an authentication information loading module 303 is further included, which loads the authentication information and generates an image gray value of the authentication information. The authentication information can be in various types, such as common ciphertext forms, watermark information, etc., and can also generate noise with white noise characteristics, especially white noise with statistically independent characteristics, so that this method can not only maximize The local authentication data is added to the original data with less interference, and the acquisition party is separated from the authentication information.

In this embodiment, an image superimposition module 304 is further included, which superimposes the image gradation value of the authentication information on the image gradation value of the original data to form a superimposed gradation image. The process of loading the authentication information is generally performed by superposition, or other types of operations, such as XOR, same OR, phase, and splicing operations. The image gradation value of the authentication information is superimposed on the image gradation value of the original data to form a superimposed gradation image.

In this embodiment, a two-dimensional code generation module 305 is further included, which adds a finder pattern to the superimposed image gradation to generate a two-dimensional code.

In the present embodiment, generally, the channel in the two-dimensional code copying process is of a transmission type, but may also represent a process between generation and acquisition. For example, after the user generates the QR code, The two-dimensional code is displayed on the paper medium by printing, for example, on the billboard, and other authorized users can obtain the two-dimensional code by shooting or scanning. The process of generating → printing → scanning can be considered as passing The channel.

In the present embodiment, from the viewpoint of superposition, it is possible to rotate the different angles to perform superimposition after the pattern of the authentication information is determined. In particular, the angle of superposition may not be disclosed to the public, and the use of both parties to know, or the agreement between the two parties, or the two parties to negotiate and obtain the superposition angle, thereby further avoiding the malicious third party to copy and improve the security of the authentication information. .

In this embodiment, as shown in FIG. 5, after the two-dimensional code passes through the channel and is acquired, the two-dimensional code needs to be decoded, which corresponds to the steps in the process of generating the two-dimensional code, and the present embodiment provides a A two-dimensional code decoding device in the process of copying a two-dimensional code. It includes obtaining a two-dimensional code by the acquisition module 401. Generally, the two-dimensional code is obtained by shooting or scanning, and the two-dimensional code picture can also be obtained by pre-storing, downloading, instant transmission, mail receiving, etc., and then extracting the two-dimensional code by using the image processing program.

In this embodiment, the image recovery module 402 is further included: the acquired two-dimensional code image is subjected to an image restoration step to restore shape distortion, color and/or brightness distortion received by the two-dimensional code gray image in the communication channel. A first grayscale image of the two-dimensional code is obtained.

In this embodiment, the method further includes a noise removal and authentication information module 403: demodulating the first grayscale image according to a signal modulation method in the two-dimensional code generating step, removing channel noise and authentication information, and obtaining a second of the two-dimensional code. The grayscale image, the authentication information is obtained by the first grayscale image and the second grayscale image. In the middle of generating a two-dimensional code to obtain a two-dimensional code, the channel may cause some errors, which need to be corrected by decoding.

In this embodiment, the second grayscale image corresponds to the image data before the authentication information is loaded during the generation process, and therefore, the difference between the first grayscale image before decoding and the second grayscale image after decoding is performed. Operation, that is, channel noise and authentication information can be obtained. In this case, the BCH decoding method is required to separate the authentication information from the channel noise.

In the present embodiment, after the authentication information is loaded on the two-dimensional code, it can be separated in various ways. Generally, the following information can be separated from the image. In the manner, for example, edge sharpening method, gradient descent method, pixel difference method, etc., by these methods, the loaded authentication information can be separated from the image, and finally the corresponding authentication information is obtained.

If the authentication information is noise with white noise characteristics, it is necessary to separate the authentication information and the channel noise from the two-dimensional code by means of filtering, modulation or demodulation, but in this case, the authentication information and the channel noise It is separated as a whole, so it is necessary to further separate the authentication information and channel noise. In general, the authentication information can be separated using BCH decoding techniques to obtain separate authentication information.

In this embodiment, the decoding and demodulation module 404 is further included: the decoded second grayscale image is subjected to a source decoding operation to obtain a noiseless original bitstream.

The secondary decoding modulation module 405 converts the noiseless original bit data into a noiseless two-dimensional code gray value by secondary encoding and secondary modulation. Finally, the encryption and authentication of the information encoded by the user is completed by decoding the authentication information.

In addition, in the present embodiment, the following module is further included: the error correction module 406: the error introduced by the channel will be corrected by decoding. The difference operation module 407: performs a difference operation between the first grayscale image before decoding and the second grayscale image after decoding to obtain channel noise and authentication information. The noise separation module 408: separates the authentication information from the channel noise by using the BCH decoding method, and the authentication module 409: completes encryption and authentication of the information encoded by the user by decoding the authentication information.

While the invention has been described in detail with reference to the drawings and embodiments, it is understood that The present invention may be modified and changed as needed by those skilled in the art without departing from the spirit and scope of the invention, and such modifications and variations are within the scope of the invention.

Claims

A method for generating a two-dimensional code in a two-dimensional code anti-counterfeiting process, the steps of which are as follows:

Converting the original information into a bit stream by encoding;

Converting the bit stream to an image gray value of the original information;

Loading authentication information, and generating an image gray value of the authentication information;

And superimposing the image gray value of the authentication information on the image gray value of the original data to form a superimposed gray image;

A finder pattern is added next to the superimposed image gradation to generate a two-dimensional code.
The method of generating a two-dimensional code according to claim 1, wherein the loading of the authentication information comprises:

The authentication information is authentication information having a white noise characteristic.
The method of generating a two-dimensional code according to claim 1, comprising:

The generated two-dimensional code will be mixed with channel noise during transmission.
The method of generating a two-dimensional code according to any one of claims 1 to 3, wherein the superimposing the image gradation value of the authentication information onto the image gradation value of the original data comprises:

The image gradation value of the original information and the image gradation value of the authentication information are superimposed in a center-aligned manner.
The method of generating a two-dimensional code according to any one of claims 1 to 3, wherein the superimposing the image gradation value of the authentication information onto the image gradation value of the original data comprises:

The superimposed position of the image gradation value of the original information and the image gradation value of the authentication information may be in a dispersed form.
The method of generating a two-dimensional code according to any one of claims 1 to 3, wherein the superimposing the image gradation value of the authentication information onto the image gradation value of the original data comprises:

The superimposed position of the image gradation value of the original information and the image gradation value of the authentication information is set by mutual understanding, or by mutual agreement, or by mutual agreement, and is not disclosed.
The method of generating a two-dimensional code according to any one of claims 1 to 3, wherein the superimposing the image gradation value of the authentication information onto the image gradation value of the original data comprises:

The image gradation value of the original information and the image gradation value of the authentication information are superimposed in a specified pattern.
The method of generating a two-dimensional code according to any one of claims 1 to 3, wherein the superimposing the image gradation value of the authentication information onto the image gradation value of the original data comprises:

The image gradation value of the original information and the image gradation value of the authentication information are superimposed with a specified gradation value.
A two-dimensional code decoding method in a two-dimensional code copying process, the steps are as follows:

Obtain a QR code;

The obtained two-dimensional code image is subjected to an image restoration step to restore shape distortion, color and/or brightness distortion of the two-dimensional code gray image received in the communication channel, and obtain a first gray scale of the two-dimensional code. image;

Demodulating the first grayscale image according to a signal modulation method in the two-dimensional code generating step, removing channel noise and authentication information, and obtaining a second grayscale image of the two-dimensional code, by using the first grayscale image and the Decoding the second grayscale image to obtain authentication information;

Performing the demodulated second grayscale image through a source decoding operation to obtain a noiseless original bitstream;

The noiseless original bit data is converted into a noiseless two-dimensional code gray value by secondary encoding and secondary modulation.
The two-dimensional code decoding method according to claim 9, wherein the first grayscale image is demodulated according to a signal modulation method in the two-dimensional code generating step to remove channel noise and authentication information, and further includes the following steps:

The error introduced by the channel is corrected by decoding.
The two-dimensional code decoding method according to claim 10, further comprising the steps of:

Performing a difference operation between the first grayscale image before decoding and the second grayscale image after decoding to obtain the channel noise and the authentication information.
The two-dimensional code decoding method according to claim 11, further comprising the steps of:

The authentication information is separated from the channel noise using a BCH decoding method.
A two-dimensional code generating device in a two-dimensional code copying process, comprising:

a bit stream generation module: converting the original information into a bit stream by encoding;

An image conversion module: converting the bit stream into an image gray value of the original information;

An authentication information loading module: loading authentication information, and generating an image gray value of the authentication information;

An image superimposing module: superimposing an image gray value of the authentication information on an image gray value of the original data to form a superimposed gray image;

The two-dimensional code generating module: adding a finder pattern to the gray level of the superimposed image to generate a two-dimensional code.
A two-dimensional code decoding device in a two-dimensional code copying process, comprising:

Get module: Get the QR code;

Restoring the image module: the acquired two-dimensional code image is subjected to an image restoration step to restore shape distortion, color and/or brightness distortion of the two-dimensional code gray image received in the communication channel, and obtain a two-dimensional code First grayscale image;

a noise removal and authentication information module: demodulating the first grayscale image according to a signal modulation method in the two-dimensional code generation step, removing channel noise and authentication information, and obtaining a second grayscale image of the two-dimensional code, The first grayscale image and the second grayscale image obtain authentication information;

a decoding and demodulation module: the demodulated second grayscale image is subjected to a source decoding operation to obtain a noiseless original bitstream;

The secondary code modulation module converts the noiseless original bit data into a noiseless two-dimensional code gray value by secondary coding and secondary modulation.
The two-dimensional code decoding apparatus according to claim 14, further comprising:

The noise separation module: separates the authentication information from the channel noise by using a BCH decoding method.