Information processing apparatus, information processing method, medium generation apparatus, medium generation method, program, and two dimensional code medium

Abstract

To provide a technique for determining whether a two dimensional code is a duplicate.SOLUTION: An aspect of the present disclosure relates to an information processing apparatus including an acquisition unit that acquires a captured image of a two dimensional code medium, an extraction unit that extracts a two dimensional code and an anti-duplication dot image from the captured image, and a determination unit that compares a conversion result of the two dimensional code using a predetermined function with the anti-duplication dot image, and determines whether the two dimensional code medium is a duplicate based on a comparison result.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an information processing device, an information processing method, a medium generation device, a medium generation method, a program, and a two-dimensional code medium. [Background technology]

[0002] Two-dimensional barcodes and codes such as QR Code (QR Code is a registered trademark of Denso Wave Inc.) are widely used for product management and campaigns because information can be easily obtained using published procedures and equipment, and labels with printed two-dimensional barcodes can be used to embed information into objects. These two-dimensional barcodes can be reproduced using consumer copy machines and printers in a way that is difficult to distinguish visually, and detecting such reproduced and counterfeit products is a challenge in order to prevent the unauthorized use of codes by such products.

[0003] Technologies have been proposed to detect whether such two-dimensional codes are counterfeit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-161149 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above problems, an object of the present disclosure is to provide a technology for determining whether a two-dimensional code is a copy. [Means for solving the problem]

[0006] One aspect of the present disclosure relates to an information processing device having an acquisition unit that acquires an image of a two-dimensional code medium, an extraction unit that extracts a two-dimensional code and a duplication prevention dot image from the image, and a determination unit that compares the conversion result of the two-dimensional code using a predetermined function with the duplication prevention dot image and determines whether the two-dimensional code medium has been duplicated based on the comparison result. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a technique for determining whether a two-dimensional code is a copy. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram illustrating a two-dimensional code verification process according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram illustrating a two-dimensional code medium according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is a schematic diagram showing a procedure for creating a two-dimensional code medium according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a block diagram illustrating a hardware configuration of an information processing device according to an embodiment of the present disclosure. [Figure 5] FIG. 5 is a block diagram illustrating a functional configuration of an information processing device according to an embodiment of the present disclosure. [Figure 6] FIG. 6 is a schematic diagram showing a procedure for generating a copy-protected dot image according to an embodiment of the present disclosure. [Figure 7] 7A to 7C are diagrams illustrating modified examples of copy-protected dot images according to an embodiment of the present disclosure. [Figure 8] FIG. 8 is a diagram illustrating a procedure for verifying a copy-protected dot image according to an embodiment of the present disclosure. [Figure 9] FIG. 9 is a flowchart illustrating a two-dimensional code verification process according to an embodiment of the present disclosure. [Figure 10] FIG. 10 is a block diagram illustrating a functional configuration of a media generation device according to an embodiment of the present disclosure. [Figure 11]FIG. 11 is a flowchart illustrating a media generation process according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0010] In the following embodiments, a two-dimensional code medium with a copy prevention function, an information processing device for verifying the two-dimensional code medium, and a medium generating device for generating the two-dimensional code medium are disclosed.

[0011] [Summary] In the following embodiment, as shown in Fig. 1, when a user captures an image of a two-dimensional code medium 10 such as a QR code using the camera function of a user device 50 such as a smartphone, the user device 50 transmits the captured image of the two-dimensional code medium 10 to an information processing device 100. As shown in Fig. 2, the two-dimensional code medium 10 according to this embodiment is embedded with a two-dimensional code that encodes a URL (Uniform Resource Locator) of a link destination, etc., and also embedded with a copy prevention dot image 20 generated from the two-dimensional code according to a predetermined function (for example, a hash function).

[0012] When the information processing device 100 acquires a captured image from the user device 50, it executes a two-dimensional code verification process, as will be described in detail below, on the two-dimensional code medium 10 captured in the acquired captured image, and determines whether the captured two-dimensional code medium 10 is a duplicate. Then, the information processing device 100 extracts a two-dimensional code and a copy-protected dot image 20 from the captured two-dimensional code medium 10, converts the extracted two-dimensional code according to a predetermined function used to generate the copy-protected dot image 20, and compares the conversion result with the copy-protected dot image 20. Then, the information processing device 100 determines whether the captured two-dimensional code medium 10 is authentic or a duplicate based on the comparison result.

[0013] Such a two-dimensional code medium 10 can be created, for example, by a medium generation device 200 according to the creation procedure shown in Fig. 3. When a two-dimensional code 30 (e.g., a code with a pattern composed of figures, such as a QR code) in which two-dimensional code information (e.g., a character string such as a URL character string) is encoded is given, the medium generation device 200 inputs the two-dimensional code information encoded in the two-dimensional code 30 into a predetermined function (e.g., a hash function), and uses a dot image generated from the output result of the predetermined function as a copy-protected dot image 20. The medium generation device 200 can then embed the copy-protected dot image 20 in the two-dimensional code 30, thereby creating a two-dimensional code medium 10 in which the copy-protected dot image 20 is embedded.

[0014] 3, the copy-prevention dot image 20 is created with a resolution that is difficult to reproduce using a consumer printer, etc. For example, if it is created at about 1200 to 2400 dpi, it may be difficult to copy. Therefore, if the two-dimensional code medium 10 is copied, the dot pattern of the copy-prevention dot image 20 cannot be reproduced, making it possible to determine whether the two-dimensional code medium 10 has been copied, and potentially reducing the risk of fraudulent use of the two-dimensional code medium 10.

[0015] Here, the information processing device 100 may be a server or the like that acquires an image of the two-dimensional code medium 10 from a user device 50 such as a smartphone, as described above with reference to Figure 1, and executes a two-dimensional code verification process that verifies the authenticity of the two-dimensional code medium 10 based on the above-mentioned copy-proof dot image 20.

[0016] However, the information processing device 100 according to the present disclosure is not necessarily limited to this, and may be realized, for example, as a user device 50 on which an application for executing a two-dimensional code verification process is installed. In this case, the application extracts the two-dimensional code 30 and the copy-protected dot image 20 from a captured image of the two-dimensional code medium 10 captured by the user, and transmits the extracted copy-protected dot image 20 to a server of the URL embedded in the two-dimensional code 30. Upon receiving the copy-protected dot image 20 from the user device 50, the server may compare the result of conversion from the URL character string using a predetermined function with the received copy-protected dot image 20, and verify the authenticity of the two-dimensional code medium 10 based on the comparison result.

[0017] In the following embodiment, the information processing device 100 is realized as a server connected to the user device 50 for communication, but the information processing device 100 can be realized as the user device 50 in the same manner.

[0018] Here, the information processing device 100 and the media generation device 200 may have, for example, a hardware configuration as shown in Fig. 4. That is, the information processing device 100 and the media generation device 200 have an interface device 101, a storage device 102, a memory device 103, a processor 104, a user interface (UI) device 105, and a communication device 106, which are interconnected via a bus B.

[0019] Programs and / or data that realize various functions and processes in the information processing device 100 and the media generation device 200 are downloaded to the storage device 102 or memory device 103 via the interface device 101 from an external device and / or a network.

[0020] The storage device 102 is realized by a non-volatile memory or the like, and stores installed or downloaded programs or data (for example, files, etc.).

[0021] The memory device 103 is realized by a random access memory, a static memory, or the like, and when a program or instruction is activated, reads and stores the program, instruction, data, or the like from the storage device 102. The storage device 102, the memory device 103, and the removable storage medium may be collectively referred to as a non-transitory storage medium.

[0022] The processor 104 may be realized by one or more CPUs (Central Processing Units), GPUs (Graphics Processing Units), processing circuitry, etc., which may be composed of one or more processor cores, and performs various functions and processes of the information processing device 100 and the media generation device 200 in accordance with programs, instructions, data such as parameters required to execute the programs or instructions, etc. stored in the memory device 103.

[0023] The user interface (UI) device 105 may be composed of input devices such as a keyboard, mouse, camera, microphone, etc., output devices such as a display, speaker, headset, printer, etc., and input / output devices such as a touch panel, and realizes an interface between the user and the information processing device 100 and the medium generating device 200. For example, the user may operate the information processing device 100 and the medium generating device 200 by operating a keyboard, mouse, etc. to use a GUI (Graphical User Interface) displayed on a display or touch panel.

[0024] The communication device 106 is realized by various communication circuits that execute wired and / or wireless communication processing with external devices, the Internet, a LAN (Local Area Network), a cellular network, or other communication networks.

[0025] However, the above-described hardware configuration is merely an example, and the information processing device 100 and the medium generation device 200 according to the present disclosure may be realized by any other appropriate hardware configuration.

[0026] [Information processing device] An information processing device 100 according to an embodiment of the present disclosure will be described. Fig. 5 is a block diagram showing a functional configuration of the information processing device 100 according to an embodiment of the present disclosure. As shown in Fig. 5, the information processing device 100 includes an acquisition unit 110, an extraction unit 120, and a determination unit 130. For example, one or more functional units of the acquisition unit 110, the extraction unit 120, and the determination unit 130 may be realized by one or more processors 104 executing one or more programs or instructions.

[0027] The acquisition unit 110 acquires a captured image of the two-dimensional code medium. For example, the acquisition unit 110 acquires a captured image showing the two-dimensional code medium 10 captured by a user from the user device 50. Upon acquiring the captured image, the acquisition unit 110 passes the acquired captured image to the extraction unit 120.

[0028] Here, the copy-protected dot image 20 may be generated based on the result of a hash function conversion of a character string derivable from the two-dimensional code 30. Specifically, the copy-protected dot image 20 can be generated as follows and embedded in the two-dimensional code medium 10. That is, as shown in FIG. 6, the two-dimensional code information encoded in the two-dimensional code 30 is converted using a predetermined function. For example, a character string, such as a URL character string, encoded in the two-dimensional code 30 is input to a secret hash function to calculate a hash value. Next, the calculated hash value is converted into a binary number to generate the copy-protected dot image 20, with "0" as white and "1" as black. The generated copy-protected dot image 20 is then embedded in the two-dimensional code medium 10. Even if the copy-protected dot image 20 is superimposed on the two-dimensional code 30, the two-dimensional code information can be extracted because the two-dimensional code 30 has redundancy. The purposes of converting a character string into a hash value in this way are: 1) input and output are uniquely determined, i.e., identity (QR codes attached to other products cannot be reused, etc.); 2) it is difficult for an external attacker to guess the function itself or the copy-resistant dot image 20, i.e., irreversibility (not only cannot be copied but also cannot be forged); and 3) the computational cost of generating a dot image from a URL character string is almost zero.

[0029] When the copy prevention dot image 20 is embedded in the two-dimensional code medium 10, a frame line may be added to the copy prevention dot image 20. This makes it possible to easily recognize the boundary of the copy prevention dot image 20. Furthermore, the arrangement area or relative position of the copy prevention dot image 20 within the two-dimensional code 30 may be registered in a database or the like. This makes it possible to identify the arrangement position of the copy prevention dot image 20 in the two-dimensional code medium 10, and the copy prevention dot image 20 may be extracted with higher accuracy.

[0030] Although a hash function can be used as the predetermined function, the predetermined function according to the present disclosure is not limited to this. For example, any other function that outputs the same value for the same input, outputs different values ​​for different inputs, and makes it impossible to decrypt the input from the output value can be used.

[0031] Furthermore, the copy prevention dot image 20 does not necessarily have to be embedded within the two-dimensional code as shown in Fig. 7A. The copy prevention dot image 20 may be located not only within the two-dimensional code but also within or near the finder pattern of the two-dimensional code. For example, as shown in Fig. 7B, the copy prevention dot image 20 may be embedded within the finder pattern of the two-dimensional code 30, or may be embedded near the two-dimensional code 30 as shown in Fig. 7C. The finder pattern is used as a marker for aligning the two-dimensional code.

[0032] The extraction unit 120 extracts the two-dimensional code 30 and the copy-protected dot image 20 from the captured image. Specifically, the extraction unit 120 extracts the two-dimensional code 30 based on the finder pattern, and can extract the copy-protected dot image 20 based on the arrangement area of ​​the copy-protected dot image 20 on the two-dimensional code medium 10 stored in the database. The extraction unit 120 passes the extracted two-dimensional code 30 and copy-protected dot image 20 to the determination unit 130.

[0033] The determination unit 130 compares the result of transforming the two-dimensional code 30 using a predetermined function with the copy-protected dot image 20, and determines whether the two-dimensional code medium 10 has been copied based on the comparison result. Specifically, as shown in Fig. 8, the determination unit 130 compares the copy-protected dot image 20 extracted from the two-dimensional code medium 10 with a dot image 40 as a result of transforming the two-dimensional code 30 extracted from the two-dimensional code medium 10 using a predetermined function. Specifically, the determination unit 130 may calculate the difference between the copy-protected dot image 20 and the dot image 40, and determine whether the two-dimensional code medium 10 has been copied based on whether the calculated difference is less than a predetermined threshold.

[0034] If the difference between the copy-protected dot image 20 and the conversion result 40 is equal to or greater than a predetermined threshold, the determination unit 130 may determine that there is a significant difference between the copy-protected dot image 20 and the conversion result 40, and determine that the two-dimensional code medium 10 has been copied. On the other hand, if the difference between the copy-protected dot image 20 and the conversion result 40 is less than the predetermined threshold, the determination unit 130 may determine that the copy-protected dot image 20 and the conversion result 40 are substantially identical, and determine that the two-dimensional code medium 10 has not been copied. Generally, it is difficult for a consumer printer to reproduce the copy-protected dot image 20, and as a result, a significant difference occurs between the copy-protected dot image 20 and the conversion result 40. Therefore, it is possible to determine identity using such a threshold determination. Furthermore, by using the conversion result 40, such as a hash value, it becomes difficult for a consumer printer to reproduce the copy-protected dot image 20, and misuse and counterfeiting of the two-dimensional code medium 10 can be prevented.

[0035] The difference is not limited to the normal difference between the copy prevention dot image 20 and the conversion result 40, and for example, the determination unit 130 may calculate the exclusive OR of the black pixels in each square as the difference.

[0036] In one embodiment, the determination unit 130 may input a character string extracted from the two-dimensional code 30 into a hash function and obtain a hash value from the hash function as the conversion result. Specifically, the determination unit 130 obtains a URL character string as two-dimensional code information of the extracted two-dimensional code 30, inputs the obtained URL character string into the hash function, and obtains a hash value. The determination unit 130 then converts the obtained hash value into a binary number and generates a dot image based on the converted binary number. Thereafter, the determination unit 130 calculates the difference between the generated dot image and the copy-protected dot image 20, and can determine whether the captured two-dimensional code medium 10 is a copy depending on whether the calculated difference is less than a predetermined threshold.

[0037] According to the above-described information processing device 100, by taking advantage of the difficulty of reproducing the copy-prevention dot image 20 using a consumer printer or the like, it is possible to make it difficult to copy the two-dimensional code medium 10 and reduce fraudulent use of the two-dimensional code medium 10.

[0038] [2D code verification processing] Next, a two-dimensional code verification process according to an embodiment of the present disclosure will be described. The verification process can be realized by the information processing device 100, more specifically, by the processor 104 of the information processing device 100 executing a program stored in the memory device 103. Fig. 9 is a flowchart showing the two-dimensional code verification process according to an embodiment of the present disclosure.

[0039] In step S101, the information processing device 100 acquires a captured image of the two-dimensional code medium 10. For example, if the information processing device 100 is realized as a server communicatively connected to the user device 50, when a user captures an image of a two-dimensional code medium 10 such as a QR code using a camera function of the user device 50 such as a smartphone, the information processing device 100 may acquire the captured image of the two-dimensional code medium 10 from the user device 50. Alternatively, if the information processing device 100 is realized by an app installed in the user device 50 that executes the two-dimensional code verification process, when a user captures an image of a two-dimensional code medium 10 such as a QR code using a camera function of the user device 50 such as a smartphone, the app may acquire the captured image of the captured two-dimensional code medium 10.

[0040] In step S102, the information processing device 100 extracts the two-dimensional code 30 and the copy-protected dot image 20 from the two-dimensional code medium 10. Specifically, the information processing device 100 identifies and extracts the two-dimensional code 30 and the copy-protected dot image 20 from the captured image of the two-dimensional code medium 10 acquired in step S101. For example, the two-dimensional code 30 may be extracted based on a finder pattern, and the copy-protected dot image 20 may be extracted based on the arrangement area of ​​the copy-protected dot image 20 registered when the two-dimensional code medium 10 was created.

[0041] In step S103, the information processing device 100 converts the two-dimensional code 30 using a predetermined function. The predetermined function may be, for example, a hash function used when creating the two-dimensional code medium 10. The information processing device 100 extracts two-dimensional code information (e.g., a URL character string) encoded in the two-dimensional code 30 from the two-dimensional code 30 extracted in step S102, and inputs the extracted two-dimensional code information into the hash function to obtain a hash value. The information processing device 100 then converts the obtained hash value into a binary number and generates a dot image as the conversion result 40 based on the obtained binary number. For example, the dot image may be generated with the binary number "0" as white and "1" as black.

[0042] In step S104, the information processing device 100 compares the conversion result 40 with the duplication prevention dot image 20. Specifically, the information processing device 100 calculates the difference between the dot image as the conversion result 40 acquired in step S103 and the duplication prevention dot image 20 extracted in step S102.

[0043] In step S105, the information processing device 100 determines whether the two-dimensional code medium 10 is a duplicate based on the comparison result. For example, if the difference calculated between the conversion result 40 and the copy-protected dot image 20 is less than a predetermined threshold, the information processing device 100 may determine that the two-dimensional code medium 10 is authentic and not a duplicate. On the other hand, if the difference calculated between the conversion result 40 and the copy-protected dot image 20 is equal to or greater than a predetermined threshold, the information processing device 100 may determine that the two-dimensional code medium 10 is not authentic and is a duplicate.

[0044] According to the above-described two-dimensional code verification process, by taking advantage of the difficulty of reproducing the copy-prevention dot image 20 using a consumer printer or the like, it is possible to make it difficult to copy the two-dimensional code medium 10 and reduce the fraudulent use of the two-dimensional code medium 10.

[0045] [Media generation device] Next, a medium generating device 200 according to an embodiment of the present disclosure will be described. When the medium generating device 200 acquires a character string, such as a URL character string, that can be derived from the two-dimensional code 30 to be superimposed on the two-dimensional code medium 10 to be generated, the medium generating device 200 applies a predetermined function to the character string. Then, the medium generating device 200 generates a copy-protected dot image 20 based on the result of converting the character string using the predetermined function, and adds the image to the two-dimensional code medium 10.

[0046] 10 is a block diagram showing the functional configuration of a media generation device 200 according to one embodiment of the present disclosure. As shown in FIG. 10, the media generation device 200 includes an acquisition unit 210, a conversion unit 220, and a generation unit 230. For example, one or more functional units of the acquisition unit 210, the conversion unit 220, and the generation unit 230 may be implemented by one or more processors 104 executing one or more programs or instructions.

[0047] The acquisition unit 210 acquires a character string that can be derived from the two-dimensional code 30 on the two-dimensional code medium 10. For example, the character string may be a URL character string embedded in the two-dimensional code 30. By capturing an image of the two-dimensional code 30 with a camera or the like, a user can access the link destination of the URL character string embedded in the two-dimensional code 30. The acquisition unit 210 provides the acquired character string to the conversion unit 220.

[0048] The conversion unit 220 converts a character string using a predetermined function and obtains the conversion result of the character string. For example, the predetermined function may be a hash function, and the conversion unit 220 converts a character string using any of the hash functions and obtains the conversion result for the character string. The conversion unit 220 provides the obtained conversion result to the generation unit 230.

[0049] The generating unit 230 generates a copy-protected dot image 20 based on the conversion result and adds the copy-protected dot image 20 to the two-dimensional code medium 10. Specifically, the generating unit 230 binarizes the conversion result acquired from the converting unit 230 and generates a dot image based on the acquired binary number. For example, the dot image may be generated with the binary number "0" as white and "1" as black. Then, the generating unit 230 combines the generated dot image with the two-dimensional code medium 10 as the copy-protected dot image 20. For example, the generating unit 230 may arrange the copy-protected dot image 20 at a position as shown in FIGS. 7A to 7C.

[0050] The above-described medium generation device 100 can take advantage of the difficulty of reproducing the copy-prevention dot image 20 using a consumer printer or the like to generate a two-dimensional code medium 10 that is difficult to copy, thereby reducing the fraudulent use of the two-dimensional code medium 10.

[0051] [Media Generation Processing] Next, a media generation process according to an embodiment of the present disclosure will be described. The media generation process can be realized by the media generation device 200, more specifically, by the processor 104 of the media generation device 200 executing a program stored in the memory device 103. Figure 11 is a flowchart showing the media generation process according to an embodiment of the present disclosure.

[0052] 11, in step S201, the media generating device 200 acquires a character string that can be derived from the two-dimensional code 30 on the two-dimensional code media 10. For example, the character string may be a URL character string embedded in the two-dimensional code 30. By capturing an image of the two-dimensional code 30 with a camera or the like, a user can access the link destination of the URL character string embedded in the two-dimensional code 30.

[0053] In step S202, the media generating apparatus 200 converts the character string using a predetermined function and obtains the converted character string. For example, the predetermined function may be a hash function, and the media generating apparatus 200 obtains a hash value of the character string.

[0054] In step S203, the media generation device 200 generates a copy-protected dot image 20 based on the conversion result. Specifically, the media generation device 200 binarizes the conversion result, such as the hash value, acquired in step S202, and generates a dot image based on the acquired binary number. For example, the dot image may be generated with the binary number "0" as white and "1" as black.

[0055] In step S204, the medium generating device 200 adds the copy prevention dot image 20 to the two-dimensional code medium 10. For example, the medium generating device 200 may arrange the copy prevention dot image 20 at a position as shown in Figures 7A to 7C.

[0056] According to the above-described medium generation process, by taking advantage of the difficulty of reproducing the copy-prevention dot image 20 using a consumer printer or the like, a two-dimensional code medium 10 that is difficult to copy can be generated, thereby reducing the fraudulent use of the two-dimensional code medium 10.

[0057] Although the examples of the present disclosure have been described in detail above, the present disclosure is not limited to the specific embodiments described above, and various modifications and variations are possible within the scope of the gist of the present disclosure as set forth in the claims. [Explanation of symbols]

[0058] 50 User Device 100 Information processing device 110 Acquisition Department 120 Extraction part 130 Judgment section 200 Media generation device 210 Acquisition Department 220 Conversion Unit 230 Generation part

Claims

1. an acquisition unit that acquires a captured image of a two-dimensional code medium; an extracting unit that extracts the two-dimensional code and the copy prevention dot image from the captured image; a determination unit that compares the conversion result of the two-dimensional code using a predetermined function with the copy prevention dot image and determines whether the two-dimensional code medium is a copy based on the comparison result; An information processing device having the above.

2. The information processing device according to claim 1 , wherein the copy prevention dot image is arranged within the two-dimensional code, within a finder pattern, or in the vicinity of the two-dimensional code.

3. The information processing device according to claim 1 , wherein the predetermined function is a hash function.

4. The information processing device according to claim 3 , wherein the copy prevention dot image is generated based on a result of conversion of a character string derivable from the two-dimensional code by the hash function.

5. The information processing device according to claim 3 , wherein the determination unit inputs the character string extracted from the two-dimensional code into the hash function, and obtains a hash value from the hash function as the conversion result.

6. Obtaining a captured image of a two-dimensional code medium; extracting a two-dimensional code and a copy prevention dot image from the captured image; comparing the conversion result of the two-dimensional code using a predetermined function with the copy prevention dot image, and determining whether the two-dimensional code medium is a copy based on the comparison result; An information processing method executed by one or more computers.

7. Obtaining a captured image of a two-dimensional code medium; extracting a two-dimensional code and a copy prevention dot image from the captured image; comparing the conversion result of the two-dimensional code using a predetermined function with the copy prevention dot image, and determining whether the two-dimensional code medium is a copy based on the comparison result; A program that causes one or more computers to execute the following.

8. A two-dimensional code, a copy prevention dot image generated from the two-dimensional code using a predetermined function; A two-dimensional code medium having:

9. an acquisition unit that acquires a character string that can be derived from the two-dimensional code on the two-dimensional code medium; a conversion unit that converts the character string using a predetermined function and obtains a conversion result of the character string; a generating unit that generates a copy prevention dot image based on the conversion result and adds the copy prevention dot image to the two-dimensional code medium; A media generation device comprising:

10. Obtaining a character string derivable from a two-dimensional code on a two-dimensional code medium; converting the character string using a predetermined function and obtaining a result of the conversion of the character string; generating a copy prevention dot image based on the conversion result, and adding the copy prevention dot image to the two-dimensional code medium; A media generation method, the method being performed by one or more computers.

11. Obtaining a character string derivable from a two-dimensional code on a two-dimensional code medium; converting the character string using a predetermined function and obtaining a result of the conversion of the character string; generating a copy prevention dot image based on the conversion result, and adding the copy prevention dot image to the two-dimensional code medium; A program that causes one or more computers to execute the following.

Images