Method for acquiring optical PUF-based encryption code and optical PUF-based encryption code acquired using same

Abstract

An embodiment of the present invention provides a method for acquiring an optical PUF-based encryption code, which is different from a semiconductor-based PUF, and an optical PUF-based encryption code acquired using same. Here, the method for acquiring an optical PUF-based encryption code includes the steps of: preparing a refractive index anisotropic material; transmitting light through the refractive index anisotropic material and receiving the light having been transmitted through the refractive index anisotropic material so as to acquire a basic image having an interference pattern; generating a binary code image having a binary code corresponding to the interference pattern; generating an image cube by stacking a plurality of binary code images; and selecting a surface including a plurality of binary code images from the image cube and extracting a binary code from the surface so as to generate an optical PUF-based encryption code.

Description

Method for obtaining optical PUF-based encryption code and optical PUF-based encryption code obtained using the same

[0001] The present invention relates to a method for obtaining an optical PUF-based encryption code and an optical PUF-based encryption code obtained using the same, and more particularly, to a method for obtaining an optical PUF-based encryption code different from a semiconductor-based PUF and an optical PUF-based encryption code obtained using the same.

[0002]

[0003] Digital technologies connected to the Internet are rapidly advancing. Technologies such as the Internet of Things (IoT), big data, and cloud computing are forming a complex digital network encompassing smartphones, smart cards, and numerous ubiquitous electronic devices and home appliances. Consequently, a vast amount of digital information related to our lives is being generated, stored, and transmitted every day.

[0004] However, this digital information is vulnerable to security risks unless a high-level information security system is in place. One of the most critical aspects of an information security system is the authentication of entities or individuals seeking access to information. This authentication protocol is typically a unique, unclonable digital signature, similar to a fingerprint.

[0005] Recently, research on Physical Unclonable Function (PUF) technology (hereinafter referred to as 'PUF') is being actively conducted as an alternative to information security systems.

[0006] PUFs derive from the unique characteristics of each semiconductor chip, which arise from the characteristics of its manufacturing process. Because they output unpredictable values ​​in hardware, they are impossible to replicate. Research has explored various PUF types, leveraging these characteristics, including arbiter-PUFs, ring oscillator (RO)-PUFs, loopPUFs, and VIA-PUFs.

[0007] However, existing semiconductor-based PUFs require physical replacement or additional hardware components, and PUF technology that can be implemented without these requirements and technology for obtaining encryption codes using such PUF technology are required.

[0008] <Prior Art Literature>

[0009] Republic of Korea Patent Publication No. 2022-0000815 (published on January 4, 2022)

[0010]

[0011] In order to solve the above problems, the technical task of the present invention is to provide a method for obtaining an optical PUF-based encryption code that is different from a semiconductor-based PUF, and an optical PUF-based encryption code obtained using the same.

[0012] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0013]

[0014] In order to achieve the above technical task, one embodiment of the present invention provides an optical PUF-based encryption code acquisition method, characterized by including a material preparation step of preparing a refractive index anisotropic material; a basic image acquisition step of transmitting light through the refractive index anisotropic material and receiving the light transmitted through the refractive index anisotropic material to acquire a basic image having an interference pattern; a binary code image generation step of generating a binary code image having a binary code corresponding to the interference pattern; an image cube generation step of stacking a plurality of the binary code images to generate an image cube; and an encryption code generation step of selecting a surface including a plurality of the binary code images in the image cube and extracting a binary code from the surface to generate an optical PUF-based encryption code.

[0015] In an embodiment of the present invention, the refractive index anisotropic material may be a liquid crystal material that has not undergone an alignment process.

[0016] In an embodiment of the present invention, the refractive anisotropic material has wrinkles, and the interference pattern can be formed to correspond to the wrinkles.

[0017] In an embodiment of the present invention, in the basic image acquisition step, the basic image is acquired by receiving light passing through a crossed polarizing plate placed with the refractive index anisotropic material between them, and the basic image may have a random interference pattern depending on the rotation angle of the crossed polarizing plate with respect to the refractive index anisotropic material.

[0018] In an embodiment of the present invention, in the encryption code generation step, the surface may be a two-dimensional surface formed by three randomly selected points among the image cubes.

[0019] In an embodiment of the present invention, the surface may be selected from a laminated surface formed by stacking a plurality of binary code images on the image cube.

[0020] In an embodiment of the present invention, the surface may be selected from within the image cube.

[0021] In an embodiment of the present invention, in the encryption code generation step, the surface may be at least one of the surfaces of a three-dimensional shape formed by four or more randomly selected points among the image cubes.

[0022] In an embodiment of the present invention, a binary code image verification step for verifying the randomness of the binary code image based on the binary code may be included.

[0023] In an embodiment of the present invention, an image cube verification step for verifying the randomness, uniqueness, and reliability of the image cube may be included.

[0024] Meanwhile, in order to achieve the above technical task, one embodiment of the present invention provides an optical PUF-based encryption code obtained using an optical PUF-based encryption code obtaining method.

[0025]

[0026] According to an embodiment of the present invention, an optical PUF-based basic image capable of forming a specific pattern code such as a fingerprint can be produced by utilizing the randomness of liquid crystal distribution and the optical effect of liquid crystals.

[0027] Additionally, according to an embodiment of the present invention, unlike conventional semiconductor-based PUFs, PUF configuration is possible without requiring physical replacement or additional hardware components.

[0028] Furthermore, according to an embodiment of the present invention, the randomly oriented, free-form wrinkles of the optical PUF-based base image are physically non-reproducible. Therefore, the optical PUF-based binary code image generated using the optical PUF-based base image and the optical PUF-based image cube generated by stacking the binary code images can be applied to anti-counterfeiting technology as a simple authentication method in applications with a higher level of security.

[0029] Additionally, according to an embodiment of the present invention, the obtained optical PUF-based encryption code is a one-dimensional code and can be utilized in a sequential authentication process.

[0030] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the composition of the invention described in the claims.

[0031]

[0032] FIG. 1 is a flowchart illustrating a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention.

[0033] FIG. 2 is a photograph showing a refractive index anisotropic material, a basic image, and a binary code image in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention.

[0034] FIG. 3 is an exemplary diagram showing an example of the arrangement of a cross-polarizing plate and a refractive index anisotropic material in an optical PUF-based encryption code acquisition method according to one embodiment of the present invention.

[0035] FIG. 4 illustrates a basic image and a binary code image according to a cross-polarization plate angle in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention.

[0036] FIG. 5 is a graph showing entropy along each axis of a binary code image in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention.

[0037] FIG. 6 illustrates an image cube generated in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention.

[0038] FIG. 7 is a graph showing the entropy of an image cube in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention.

[0039] FIG. 8 is a graph showing intra-HD and inter-HD of an image cube in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention.

[0040] FIG. 9 is an exemplary diagram for explaining a two-dimensional surface selected from an image cube in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention.

[0041] FIG. 10 is an exemplary diagram illustrating an example of generating an optical PUF-based encryption code in a two-dimensional plane selected in FIG. 9.

[0042] FIG. 11 is an exemplary diagram showing a three-dimensional shape selected from an image cube in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention.

[0043] FIG. 12 is an exemplary diagram illustrating an example of generating an optical PUF-based encryption code on each side of a three-dimensional shape selected in FIG. 11.

[0044]

[0045] A most preferred embodiment according to the present invention provides a method for obtaining an optical PUF-based encryption code, comprising: a material preparation step of preparing a refractive index anisotropic material; a basic image acquisition step of transmitting light through the refractive index anisotropic material and obtaining a basic image having an interference pattern by receiving the light transmitted through the refractive index anisotropic material; a binary code image generation step of generating a binary code image having a binary code corresponding to the interference pattern; an image cube generation step of stacking a plurality of the binary code images to generate an image cube; and an encryption code generation step of selecting a surface including a plurality of the binary code images in the image cube and extracting a binary code from the surface to generate an optical PUF-based encryption code.

[0046]

[0047] Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention can be implemented in various different forms and is therefore not limited to the embodiments described herein. In the drawings, irrelevant parts have been omitted for clarity of description, and similar parts have been designated with similar reference numerals throughout the specification.

[0048] Throughout the specification, when a part is said to be "connected (connected, contacted, or coupled)" to another part, this includes not only cases where it is "directly connected," but also cases where it is "indirectly connected" with another part in between. Furthermore, when a part is said to "include" a component, this does not exclude other components, but rather implies that it may include other components, unless otherwise specifically stated.

[0049] The terminology used herein is merely used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, it should be understood that the terms "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0050] While this method is depicted as a series of numbered steps for clarity, the numbering sequence does not dictate the order of the steps. Some of these steps may be skipped, performed in parallel, or performed without strict sequential order. However, this method generally proceeds according to the numbered order of the steps shown.

[0051] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0052]

[0053] FIG. 1 is a flowchart illustrating a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention, and FIG. 2 is a photograph illustrating a refractive anisotropic material, a basic image, and a binary code image in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention.

[0054] As shown in FIGS. 1 and 2, the optical PUF-based encryption code acquisition method may include a material preparation step (S110), a basic image acquisition step (S120), a binary code image generation step (S130), an image cube generation step (S150), and an encryption code generation step (S170).

[0055] Here, the material preparation step (S110) may be a step of preparing a refractive index anisotropic material (200).

[0056] And, the basic image acquisition step (S120) may be a step of transmitting light through a refractive index anisotropic material and receiving the light transmitted through the refractive index anisotropic material to acquire a basic image (300) having an interference pattern (310).

[0057] Additionally, the binary code image generation step (S130) may be a step of generating a binary code image (400) having a binary code corresponding to the interference pattern (310).

[0058] In addition, the image cube generation step (S150) may be a step of generating an image cube by stacking multiple binary code images.

[0059] In addition, the encryption code generation step (S170) may be a step of selecting a surface including multiple binary code images from an image cube, extracting a binary code from the selected surface, and generating an optical PUF-based encryption code.

[0060] The optical PUF-based encryption code generated by this method is physically unclonable. Therefore, optical PUF-based encryption code can be applied as a simple authentication method and tamper-proof technology in higher-security applications.

[0061] In detail, the material preparation step (S110) may be a step of preparing a refractive index anisotropic material (200).

[0062] Here, the refractive index anisotropic material (200) may be a liquid crystal material that has not undergone an alignment process. For example, the refractive index anisotropic material (200) may be a liquid crystal material that has not undergone an alignment process, or a liquid crystal polymer that has not undergone an alignment process.

[0063] The refractive index anisotropic material (200) may have wrinkles (210) and may have optical anisotropy. The wrinkles (210) may be formed by curing the refractive index anisotropic material.

[0064] The basic image acquisition step (S120) may be a step of transmitting light through a refractive index anisotropic material (200) and receiving the light transmitted through the refractive index anisotropic material (200) to acquire a basic image (300) having an interference pattern (310).

[0065] In the basic image acquisition step (S120), the basic image (300) can be acquired by receiving light that has passed through a cross-polarizing plate placed with a refractive anisotropic material (200) between them.

[0066] FIG. 3 is an exemplary diagram showing an example of the arrangement of a cross-polarizing plate and a refractive index anisotropic material in an optical PUF-based encryption code acquisition method according to one embodiment of the present invention.

[0067] As further illustrated in FIG. 3, a refractive anisotropic material (200) may be placed between a pair of crossed polarizing plates (510, 520). Light (501) emitted from a light source (500) may pass through the front crossed polarizing plate (510) of the pair of crossed polarizing plates (510, 520), then pass through the refractive anisotropic material (200), and then pass through the rear crossed polarizing plate (520) before being received by the light receiving unit (530). Then, a basic image (300) may be acquired from the light received by the light receiving unit (530).

[0068] The interference pattern (310) of the basic image (300) can be formed to correspond to the wrinkles (210) of the refractive index anisotropic material (200). Since the liquid crystal has not undergone an alignment process, the shape of the wrinkles (210) can be random, and therefore, the interference pattern (310) can also be formed randomly.

[0069] Since the transmittance of light can be determined by the direction of the liquid crystal, an interference pattern (310) can be formed due to the randomness of the brightness of light between the crossed polarizing plates (510, 520).

[0070] In addition, the base image (300) may have a random interference pattern depending on the rotation angle of the crossed polarizing plates (510, 520) based on the refractive index anisotropic material (200). In other words, since the light transmittance of the random wrinkles based on the refractive index anisotropic material also changes each time the angle of the crossed polarizing plates is changed, the binary code obtained through the interference pattern may also change.

[0071] FIG. 4 illustrates a basic image and a binary code image according to a cross-polarization plate angle in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention.

[0072] As shown in Fig. 4, it can be confirmed that the interference pattern (310) of the basic image obtained when the angle of the cross polarizing plate (510, 520) is rotated in units of 5° is formed differently. Here, the basic image in the case where the rotation angle of the cross polarizing plate (510, 520) changes in units of 5° is described as an example, but even if the rotation angle changes in units of 1°, the interference pattern (310) of the basic image obtained can be formed differently.

[0073] Referring again to FIGS. 1 to 4, the binary code image generation step (S130) may be a step of generating a binary code image (400) having a binary code corresponding to an interference pattern (310).

[0074] In the binary code image generation step (S130), the binary code can be generated by algorithmically filtering the interference pattern (310) of the basic image (300). The binary code image (400) can be an image of the generated binary code.

[0075] The binary code can be set to "0" and "1". The binary code can be formed in a natural shape resembling the wrinkles of a liquid crystal, as in (c) of Fig. 2. That is, when the white part of the binary code image (400) is "0" and the black part is "1", the more the binary code image (400) is divided into smaller pixels, the more it can be formed in a natural shape resembling the wrinkles of a liquid crystal. In addition, since the number of binary codes included in a binary code image of the same size also increases, it can have a more detailed binary code.

[0076] Meanwhile, when considering the operation processing speed for the generated binary code image (400), the binary code may be generated in a more simplified form in the form of square pixels.

[0077] Since the binary code of the binary code image (400) is formed corresponding to the interference pattern (310) of the basic image (300), as shown in FIG. 4, the binary code of the binary code image (400) generated corresponding to each basic image can also be formed differently by the basic image having a different type of interference pattern depending on the rotation angle of the cross polarizing plate.

[0078] The method for obtaining an optical PUF-based encryption code may include a binary code image verification step (S140).

[0079] The binary code image verification step (S140) may be a step for verifying the randomness of a binary code image based on the binary code.

[0080] FIG. 5 is a graph showing entropy along each axis of a binary code image in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention.

[0081] Entropy, which is measured using the Shannon entropy equation, can be a measure of randomness as it is expressed by calculating the probability of the binary code being set to "0" or "1".

[0082] The binary code image used for entropy measurement consisted of 250 pixels × 250 pixels and a total of 62,500 bits.

[0083] Then, we measured the entropy (Ex,y) along the rows (X-axis) and columns (Y-axis) of the binary code using standard equations. Here, Ex,y is defined as the probability of being set to "1" along each axis.

[0084] The average entropy (Ex) along the x-axis was measured as 0.9894±0.02 (see (a) of Fig. 5), and the average entropy (Ey) along the y-axis was measured as 0.9877±0.03 (see (b) of Fig. 5). Since this is close to the value of 1, which is close to complete randomness, it can be confirmed that the binary code is completely random.

[0085] FIG. 6 illustrates an image cube generated in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention, FIG. 7 is a graph illustrating entropy of an image cube in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention, and FIG. 8 is a graph illustrating intra-HD and inter-HD of an image cube in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention.

[0086] As shown in FIG. 1 and FIG. 6 to FIG. 8, the image cube generation step (S150) may be a step of generating an image cube (600) by stacking multiple binary code images (400).

[0087] In the image cube generation step (S150), multiple binary code images (400) can be formed by being stacked in the Z-axis direction. The image cube (600) itself can be random three-dimensional data. The data on the X-axis and Y-axis surfaces of the image cube (600) can also be random.

[0088] The optical PUF-based encryption code acquisition method may include an image cube verification step (S160).

[0089] The image cube verification step (S160) may be a step for verifying the randomness and uniqueness of the image cube (600).

[0090] First, in order to verify the randomness of the image cube (600), the entropy of the image cube (600) can be measured here as well using the Shannon entropy equation.

[0091] The image cube (600) used for entropy measurement was configured with a size of 250 pixels × 250 pixels × 250 pixels. The entropy of the image cube (600) was measured as 0.9912±0.02 based on the probability that each bit of the image cube (600) is set to "1." This is close to the value of 1, which is close to complete randomness, so it can be confirmed that the binary code is completely random (see Fig. 7).

[0092] And, in order to verify the uniqueness and reliability of the image cube (600), the Hamming Distance (hereinafter referred to as 'HD') can be measured.

[0093] HD is a measure of similarity defined by the number of unequal bits at a given bit position. For example, the HD between '110010' and '101011' is 3.

[0094] HD has an intra-HD (hereinafter referred to as 'intra-HD') that is calculated by measuring an image cube formed by the interference pattern of the same sample multiple times, and an inter-HD (hereinafter referred to as 'inter-HD') that is calculated by measuring multiple times with the interference pattern of different samples.

[0095] The value of intra-HD, calculated by measuring the interference pattern of the same sample multiple times, should ideally be 0.

[0096] To this end, a single image cube was measured multiple times. Specifically, 70 intra-HD responses were measured using a single image cube. As a result, the intra-HD was 0.0512.

[0097] And, the value of the inter-Hamming distance (inter-HD), which is calculated by measuring multiple times with the interference pattern of different samples, should ideally be 0.5.

[0098] To this end, multiple measurements were performed on different image cubes. Specifically, the inter-HD was measured using 70 different image cubes. The inter-HD was 0.4989.

[0099] That is, the measurement results showed that intra-HD was 0.0512, which is close to the ideal value of 0, and inter-HD was 0.4989, which is close to the ideal value of 0.5, confirming that the binary code is unique and reliable (see Figure 8).

[0100] In this way, the randomness of the binary code image and the randomness, uniqueness and reliability of the image cube have been verified, and the optical PUF-based encryption code obtained using the image cube, which will be described later, can be applied to anti-counterfeiting technology at a high level of security.

[0101] FIG. 9 is an exemplary diagram for explaining a two-dimensional surface selected from an image cube in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention, and FIG. 10 is an exemplary diagram for explaining an example of generating an optical PUF-based encryption code from a two-dimensional surface selected in FIG. 9.

[0102] As shown in FIG. 1, FIG. 6, FIG. 9, and FIG. 10, the encryption code generation step (S170) may be a step of selecting a surface including a plurality of binary code images (400) in an image cube (600), extracting a binary code from the selected surface, and generating an optical PUF-based encryption code.

[0103] In the encryption code generation step (S170), the surface may be a two-dimensional surface formed by three points randomly selected from among the image cubes (600).

[0104] And, the two-dimensional surface may be selected from a laminated surface formed by laminating multiple binary code images in an image cube (600). Here, the laminated surface may be a surface formed by multiple binary code images. That is, the laminated surface may be a side surface of the image cube (600). Accordingly, although two laminated surfaces (601, 602) are illustrated in (a) of FIG. 9, there are two more laminated surfaces that are covered and not visible.

[0105] In (a) of Fig. 9, when a two-dimensional surface (610) formed by three points (P1, P2, P3) is selected on the right-hand laminated surface (601), a binary code can be extracted from the selected two-dimensional surface (610) to generate an optical PUF-based encryption code (700) (see Fig. 10).

[0106] That is, the selected two-dimensional surface (610) becomes a surface on the YZ plane, and the selected two-dimensional surface (610) can form a new binary code by a binary code on the YZ plane among the binary codes of the multiple stacked binary code images. The optical PUF-based encryption code (700) can be generated by extracting a new binary code that the selected two-dimensional surface (610) has on the YZ plane.

[0107] An optical PUF-based encryption code (700) may be composed of, for example, binary codes sequentially extracted along the row direction while changing columns in a two-dimensional plane (610).

[0108] Here, the extracted binary code can be reconstructed into an optical PUF-based encryption code (700) through a preset algorithm. The optical PUF-based encryption code (700) may be a one-dimensional code. In other words, the optical PUF-based encryption code (700) may be a one-dimensional solution of a two-dimensional binary code stored on a two-dimensional surface (610).

[0109] One-dimensional codes can exhibit high security by exhibiting a distribution that is not biased toward "0" or "1." Therefore, optical PUF-based encryption codes (700) can be applied to various security-related fields, such as security technology, anti-counterfeiting technology, and access control systems.

[0110] In the same way, in (a) of FIG. 9, when a two-dimensional surface (620) formed by three points (P4, P5, P6) on the left-side laminated surface (602) is selected, the selected two-dimensional surface (620) has a new binary code on the XZ plane, and this new binary code can be extracted to generate another optical PUF-based encryption code.

[0111] By varying the size, position, and shape of the surface formed by the three points on the laminated surface, a surface with a new binary code can be obtained. This allows for the creation of countless surfaces, enabling the creation of optical PUF-based encryption codes with randomness, uniqueness, and reliability.

[0112] And, as seen in (b) of Fig. 9, in the encryption code generation step (S170), a two-dimensional surface formed by three randomly selected points from among the image cubes (600) may be selected from the inside of the image cube (600).

[0113] In this case, the two-dimensional surface formed may be selected so as not to be a surface on the same XY plane. For this purpose, the three points (P7, P8, P9) may be selected so as not to be located on the same XY plane. The two-dimensional surface (630) formed by the three points (P7, P8, P9) may be slanted or may be vertical.

[0114] Meanwhile, in the encryption code generation step (S170), the surface may be one or more surfaces of a three-dimensional shape formed by four or more points randomly selected from among the image cubes (600).

[0115] FIG. 11 is an exemplary diagram showing a three-dimensional shape selected from an image cube in a method for obtaining an optical PUF-based encryption code according to an embodiment of the present invention, and FIG. 12 is an exemplary diagram explaining an example of generating an optical PUF-based encryption code on each side of the three-dimensional shape selected in FIG. 11.

[0116] As shown in FIGS. 11 and 12, when four random points (P11, P12, P13, P14) are selected from an image cube (600), a three-dimensional shape (640) can be formed by the four selected points (P11, P12, P13, P14). In addition, the three-dimensional shape (640) formed by the four points can have four surfaces (641, 642, 643, 644). The surface used in the encryption code generation step (S170) can be one or more of the four surfaces (641, 642, 643, 644). In addition, an optical PUF-based encryption code (700) can be extracted from each of the selected surfaces.

[0117] Since the optical PUF-based encryption codes (710, 720, 730, 740) can be obtained from each surface (641, 642, 643, 644), each optical PUF-based encryption code (710, 720, 730, 740) can be different.

[0118] This method can help you use a three-dimensional password rather than a simple two-dimensional password.

[0119] In this way, the present invention can produce an optical PUF-based basic image that can form a specific pattern code such as a fingerprint by utilizing the randomness of liquid crystal distribution and the optical effect of liquid crystals.

[0120] And, according to the present invention, unlike conventional semiconductor-based PUFs, PUF configuration is possible without requiring physical replacement or additional hardware components.

[0121] Furthermore, according to the present invention, the free-form, randomly oriented wrinkles of the optical PUF-based base image are physically non-reproducible. Therefore, the optical PUF-based binary code image generated using the optical PUF-based base image and the optical PUF-based image cube generated by stacking the binary code images can be applied to anti-counterfeiting technology as a simple authentication method in applications with higher security levels.

[0122] In addition, the optical PUF-based encryption code obtained according to the present invention is a one-dimensional code and can be utilized in a sequential authentication process.

[0123]

[0124] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0125] The scope of the present invention is indicated by the claims set forth below, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

[0126]

[0127] <Explanation of symbols>

[0128] 200: Refractive index anisotropic material

[0129] 210: Wrinkles

[0130] 300: Default image

[0131] 310: Interference pattern

[0132] 400: Binary code image

[0133] 600: Image Cube

[0134] 610,620,630: 2D surface

[0135] 640: 3D shapes

[0136] 700: Optical PUF-based encryption code

Claims

1. Material preparation step for preparing a refractive index anisotropic material; A basic image acquisition step of transmitting light through the above refractive index anisotropic material and receiving the light transmitted through the above refractive index anisotropic material to obtain a basic image having an interference pattern; A binary code image generation step for generating a binary code image having a binary code corresponding to the above interference pattern; An image cube generation step of generating an image cube by stacking multiple binary code images; and A method for obtaining an optical PUF-based encryption code, characterized in that it includes an encryption code generation step of selecting a surface including a plurality of binary code images from the image cube and extracting a binary code from the surface to generate an optical PUF-based encryption code.

2. In paragraph 1, A method for obtaining an optical PUF-based encryption code, characterized in that the above refractive index anisotropic material is a liquid crystal material that has not undergone an orientation process.

3. In paragraph 1, The above refractive anisotropic material has wrinkles, A method for obtaining an optical PUF-based encryption code, characterized in that the above interference pattern is formed corresponding to the above wrinkles.

4. In paragraph 1, In the above basic image acquisition step, the basic image is acquired by receiving light passing through a cross-polarizing plate placed between the refractive anisotropic material, A method for obtaining an optical PUF-based encryption code, characterized in that the basic image has a random interference pattern depending on the rotation angle of the cross-polarizing plate based on the refractive index anisotropic material.

5. In paragraph 1, In the above encryption code generation step, A method for obtaining an optical PUF-based encryption code, characterized in that the above surface is a two-dimensional surface formed by three points randomly selected from the image cube.

6. In paragraph 5, A method for obtaining an optical PUF-based encryption code, characterized in that the surface is selected from a laminated surface formed by stacking a plurality of binary code images on the image cube.

7. In paragraph 5, A method for obtaining an optical PUF-based encryption code, characterized in that the above surface is selected from the inside of the image cube.

8. In paragraph 1, In the above encryption code generation step, A method for obtaining an optical PUF-based encryption code, characterized in that the surface is at least one of the surfaces of a three-dimensional shape formed by four or more randomly selected points among the image cubes.

9. In paragraph 1, A method for obtaining an optical PUF-based encryption code, characterized in that it includes a binary code image verification step for verifying the randomness of the binary code image based on the binary code.

10. In paragraph 1, A method for obtaining an optical PUF-based encryption code, characterized in that it includes an image cube verification step for verifying the randomness, uniqueness, and reliability of the image cube.

11. An optical PUF-based encryption code obtained using the optical PUF-based encryption code obtaining method described in any one of claims 1 to 10.

Images