TW201126476A - A (2,2) circular sharing techniques for two color secret images - Google Patents

Abstract

Traditional visual cryptography technique has provided sufficient security to fulfill the purpose of protecting confidential messages. In current technology, the same set of shares can be embedded with many sets of secret messages after one of the shares is rotated at different degrees. However, the used share is rectangle so that only four kinds of angle variation exist when stacking shares. Thus, when intending to embed many sets of confidential messages by using these shares, the angle variation of rotating the shares is limited. This invention proposes an improved (2, 2) circular secret sharing scheme that adapts circular shares to deal with the limitation of rotating angles in traditional visual cryptography. After completing color quantization procedure, two index's sets of color confidential images are generated. These index sets are transformed into two binary images, respectively. Then, two share generating algorithms proposed in our invention will be applied to embed two binary images into two shares. Combing stacking and rotating of two shares, the binary images can be successfully reconstructed. The share used in this invention is circular, where confidential data can be embedded in various different angle conditions. Our invention can be applied in gray-level and color confidential images. Compared with traditional visual cryptography, our invention has more flexibility, extensibility, and security.

Description

201126476 IV. Designated representative map: (1) The representative representative of the case is: (1). (1) A brief description of the symbol of the representative figure: 1. Also color secret, image c〇l〇r jmage 2. Each color secret image color image M2 3. Quantitative stone horse 4. Quantitative code Lu 5. The index value of the color secret image I I, 6. The index value of the color secret image Μ 2 ι2 7 · The binary image corresponding to the 丨 丨 value I, 二元 18 · The binary image corresponding to the index value 〇 2 9 · Share the image A 1〇·Share image β Lu 5, if there is a chemical formula in this case, please reveal the chemical formula that best shows the characteristics of the invention: 6. Invention Description: [Technical field of invention] In recent years, due to the booming development of the Internet, changes The way of traditional data transmission and connection. Therefore, many enterprises # gradually _ cyber scales to pass important documents or correct 'though _ can bring considerable convenience to the enterprise, but because the network is an open and unsafe space, through the __ road to pass the capital 201126476 It is expected that Internet hackers or illegal (four) can touch these: #料. Therefore, it has also derived the problems of Huiduo security, such as: theft of important information, tampering, etc. In view of this, 'how to ensure the safety of women's materials' can be said to be a topic worthy of consideration. Sex, ― and Shami4 proposed a new field of cryptography in 1994. Lan called it a visually confusing (visuai kan kiss). The biggest feature of this field is the original secret without any calculations. The performance of this will be identified; the improvement of the traditional cryptography in the decryption of the private need for a large number of complex calculations. The principle of visual cryptography can be extended to the group enc_on system to achieve the purpose of confidential sharing. Which is for (4) visual secret sharing scheme ((t, η) ν_]s_ siwing

Scheme), using the principle of visual cryptography, the bookmaker can use a secret message to "share the image (Slwe) to 'and each member of the group towel secretly owns - share the image; when you want to restore For confidential messages, only the shared images of at least the tamping members are printed on the slides and the slides are superimposed, and the b Κ 显示 is displayed without any calculation. Noar and Shamir also proved that if the number of sheets of the slide is less than the number of sheets, the confidential information cannot be restored anyway. Since visual fee coding is a hidden message hidden in a number of shared images of any meaning, it is impossible for a network or a person to know any information related to the hidden information from any shared image. Visual cryptography ensures the security of data communications and further protects the confidential information. In order to solve the traditional visual cryptography technology can only hide the lack of confidential information [S.1 4 201126476 ^ 'A number of scholars have proposed a variety of (A 2) visual secrets common method' such as sharing images by rotating any one The method that she can enter can also share images in two copies (4), two degrees: 90 degrees, 180 degrees, and 270 degrees, so it will be limited in the change of the rotation angle. Two again

^-Currency watermarking technology is an invisible watermarking technology. This technology is mainly used to make: under the premise that the steganqing phy will have a nuclear trademark image or a text on the imperceptible of human touch. In the image of people's reliance, the image processed by such watermarking technology cannot be easily perceived by any user. Since the watermark of the Tibetans cannot be directly detected, the two watermarking technology generally includes two parts: the watermark Tibetan program and the watermarking sequence are hidden in the watermark, and the image must be required to have a watermark. With two. It can be detected as if there is no difference in human vision; in the case where the watermark is taken out, the image is protected and the image can be removed after being maliciously altered and destroyed. The visually identifiable trademark image or text is used as copyright. For the purpose of proof, this special I. life called strong secret (nDbust) 'it is--is an important indicator to evaluate the invisible watermarking technique. At present, the digital watermarking technology can mainly detect gray images and halftone images, and the images on the printed matter are all in halftone images. The invisible watermarking technique for protecting image copyright on printed matter is the main research subject of the present invention. t si 201126476 This = method of output is mainly used to close the image sharing technique = stack image rotation method at a certain angle, you can hide two confidential messages in the image size of & and & Will not shrink. In the process of technology, our method takes every second degree as an image. First, the two black and white shadow images corresponding to the remaining image can be converted to ====Toning: respectively, the two color machine values are converted into a black and white confidential image, and the two images are generated to generate the first shared image; A public old Dandan 7, you have two black and white secret messages and quotes information: two share the image 'after you get the hidden confidential image of the cable; you can get the first color and another 1 八~贝再料 - Zhang share image rotation a-angle, value information. Then: 叠 叠 ’ 即可 即可 即可 即可 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二 第二[Prior Art] "Visual Secrets and Sh_ first proposed visual secret sharing technology. The so-called secret image technique" uses the human visual system to conduct secret cryptography bribes *=卩_行行繁_Mathematical operations In order to achieve the secret sharing mechanism, the two = two methods and derived the ") (10) type of visual machine to attack the traditional concept of the door-to-door heart-shaped secret sharing mechanism; the spirit of the method of the heart. That is, one The secret shadow 201126476 can be broken down into a different image by the door-pinch visual secret sharing mechanism. Look at this "Zhang shared image, can not get the information of the knife to the shirt. However, the score on the heart ^ In the drought image, the receiver can reconstruct the original confidential image. Later, iwam〇to and Wang and other scholars proposed that there are multiple images rotated (10) degrees to achieve the method of hiding multiple confidential information at the same time, sharing is limited to the past learning _ _ Age-occupied miscellaneous materials - there are four variations of the two, which are 0 degrees, 90 degrees, 18 degrees, and 27 degrees, and = ^ degrees are taken. The image is limited in the change of the rotation angle. 】 Ben Lai Saki Cong Saki _. Li Guan shape has the characteristic of the state of the secret message Tibetan _ to the cent. In addition, ^ (four) angle contempt to separate the two secret information in different angles, in decoding At the same time, the content of the two confidential messages was obtained by the month b. :? = Ϊ four parts, the first part is the color image quantization code, the second part is the third part is the extraction of the index value information and The fourth _reconstruction, as shown in the figure, shows that the first part of the invention will be coded as two color secret images for each of the two color secret images. Reconstruction, shooting a color image decoding process based on the general disk. As for the second part of the present invention index S.1 7 201126476 value information ^ Tibetan and the third part of the index value is taken out of the present invention The main features are 。. For the Tibetans with index value information, the present invention has two algorithms: circular shared image Α calculus '= knives' i-cut algorithm, divided into two _ quotation _ 分 分 。 。 。 【 【 本 本 本 本 本 本 本 本 本 本 本 本After the two color confidential messages are first quantized and encoded by the color palette, the two sets of index values are converted into two sets of black and white confidential information, and finally the two sets of black and white confidential information are hidden in the circular shared image. The method consists of four stages: color image quantization and coding phase =, the domain "index value information extraction phase" and the color confidential image reconstruction stage and the % color image image registration stage and the color confidential image reconstruction stage can be referred to Disc-based color image encoding and decoding process. As for: = Tibetan's Tibetan stage and the pick-up section are the main contributions of this issue (10). The value of Beixun is hidden, and the invention applies the circular sharing image technology, respectively: - Method: Circular sharing A generation algorithm and coffee branch conversion (4) Generation algorithm show knife is generated to hide two sets of color confidential images The circular depreciation of the index value is as shown in the 'Processing of the present invention. The two color confidential message % and the two-knife phase palette quantization face each generate a corresponding sum 12. Then, the two sets of index value sets are each converted into a size black and white confidential image 〇丨 and 0 and then, '-' n m 丹 Ο, and 〇 2 are shared by the present invention.

S SJ 8 201126476 respectively ― Get the first if quoted 隼人二^' wrong by completely overlapping two shared images, can be (after the rotation of the shared shadows, the age of the image is rotated, the angle is fully superimposed at the beginning, ie It is possible to take a sentence like A, and share the value with the second one. The two chips can be reconstructed by decoding the two chips.

For the image generation, the machine is divided into two 2x2 expansion blocks, where the shared image is 2x2 = the block is composed of two white sub-pixels and two black sub-pixels. : 2x2 = block f consists of a white sub-pixel and a three-_ extension at the time of '2x2' in the image of the superimposed result, '...right 丨# one white sub-pixel and three black sub-pixels, then the X2 The extended block represents a white pixel in the confidential image; if there are four black pixels, the first expanded pixel represents a black pixel in the confidential image. Next, we will describe in detail the two sub-algorithms we have invented to produce circular shared images. ―, the algorithm of circular sharing image A first sighs the radius of the circular fractal image, and $ is the circular sharing image so that the radius difference of each adjacent two circles is coincident, which is shared by the image. A consists of a space between the circle of radius, ♦ (four) and the circle of half a circle (~). When (4), h is the outermost_circle with the radius η and the radius is (4) in the shared image A.

Q 201126476 The space between the outermost second circle; that is, ^ is composed of the shared image p-axis _ medium_space. Similarly, the Μ shared image A is controlled by (4) the outermost second circle and the radius of the outermost third circle. Let Puk = PkUPk+i. ' Cutting the call with a mother-degree (degree) as a unit, so that there will be 360 arc-shaped areas. Each arcuate area connected to two degrees is a block, that is, 1 = pixel is a block, and this_block represents the corresponding position of the original image. In the three o'clock direction, the representative represents the q degree of the image, and the singularity increases the (four) and the third degree represents the first M-shaped block. The second and third degrees represent the second / * , the main 3 / 士 - arc block 'below and so on. = (4) method towel according to the present invention, which is intended to be converted like A miscellaneous Χ = 1 " Γ 旱 影 _ _ _ _ _ _ _ _ _

The number of trees, because we are 2 degrees, the unit, that is, J

Si: The angle is 2 degrees; and the Χ must also be the common factor of _, so that the 勿 匕 玉 地 将 将 勿 勿 勿 勿 勿 勿 勿 勿 勿 勿 勿 勿 勿 勿 勿 勿For the angle X of rotation, the present invention proposes a non-overlapping region such that each region/divided puk into (four) degrees per fine arc block xf° in the first region (Either select any 2x2 arc block to represent the _exclusive machine from the middle of Figure 2). Each -2x2 arc block receives a 2x2 arc corresponding to the area (ie X degrees to (five)). The type of mosquito in the black and white solid area (ie the first area) within the shaped block; its secret domain, after the 钟90 direction, _90 degrees, in other words, we only need to mess 10 201126476 The way to determine the shape of the % arc block in the area, the other area is determined by rotating the 90 degree pattern. In this way, the sigh will be produced by 360 2χ2 curved blocks. Β ^A V fine image Α’, continue to > share images Jun go j can be the second second image. In the third confidential image, the first / _ ( (4) type -, enjoy the image A, _ the first / Μ arc 2 dry image ^, the 2X2 curved block and get, and share the impact! 2X2 A 2x2: There are mosquitoes, which are 'when the image is rotated and the image is actually rotated, there is a whole 2x2 arc area, corresponding to the black #子 block in the Γ2 arc block. The block must be rotated by 9〇庐% 逆 in the counterclockwise direction by the white pixels in the 2x2 arc block of the (2) 2x2 arcs of the shared image/57 sub-image. , white like /· X, and then the type of evil to define; and share the second 2x2 arc block in the image 必须, black pure pixels in the block, ,, H1 4 image _ _ (four) 2x2 arc area & 圯 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针 针Finance (4) w material is slightly like the β towel. _ : Assume first, the prime value is black, the paste is 'degree, and the fourth (4) solid in the heart, the curved block is fcl, then share the image inside No.2χ2 Curved®, and the (10)2χ2_ block in the shared image must be, so, = 201126476 The knife is ~ When the like is in the beginning, the U solid % arc block after the overlap is the representative The yth pixel value in the secret image is white, and then the shared image is rotated by x degrees 'rotation of the shared image as the shared image A, and then the eighth:: Zone Na, and overlap with the shared image B—the seventh 7x2 arc pure block after the second is _', which means that the pixel value in the second confidential image is black.

For each of the above-mentioned steps, the above-mentioned steps are repeated, and 36 〇 arc blocks are formed in each of the calls. In this way, the first shared image can be generated. Since the arc of the arc near the circle ~ is smaller, the distribution in the curved block is also densely distributed, and the _ is also divided into _, so It may be less clear that the two sub-iv images and the port % are closer to the confidential image displayed in the center of the circle. Therefore, we limit the half-time to a certain range, and then no longer produce (10), so use the method of the (4) method to share the hollow circle of the shadow. First, the algorithm generated by the circular drought image B first, like the algorithm of the algorithm generated by the circular sharing image A, sets the radius of the fractal image, and the circle of each adjacent two circles in the shared image + servitude difference. Sub-generating Q' is composed of the space between the circle with the radius of ((4)-(iv) and the circle with the radius (for example). When h, (10) the shared image radius is ~_卜_® and The radius 咏·_ is composed of the space between the second circle; that is, at this time, the C/ Μ shared image a is converted to the middle of the outermost two. In addition, Q is the most sub-transfer image β is (four)) The second circle of the periphery and the radius of the (^) are the third circle of the space. Today CUk=ckUCk+丨. In each degree, Xiang Xiang 04, so, you can make a curved block. Each arcuate area connected by two degrees is a block, that is, 2χ2 arcs; and a block is a block. The city-block represents the pixels of the original image_corresponding position. We represent the Q degree of the image at three o'clock, and the clockwise direction represents the increment of the angle. The fourth degree and the i-th degree of 04 represent the first one, such as an arc block, the first =

Degree and 3rd degree represent the second 2x2 arc job block, and so on. In the method of the present invention, the distribution of the 〇4 _ 2 χ 2 _ block is determined according to the split image A, the first-think image 〇ι, and the second-age image 02, and the corresponding side is as shown in the table- Show. In this way, a circle of 360 arc feathers; a block is created in Ci4. For example, when sharing the image A, a 2χ2 arc-shaped block temple (such as the 1st row in the third column of the table), and the corresponding position of the first confidential image is white' and the second confidential image The pixel corresponding to the position is white, and according to the definition, the 2χ2 arc corresponding to the towel is generated as ^ (as in the 10th row of the table). Repeat the above steps to produce 360 2 χ 2 round foxes in each one. Finally, you can create a second shared image. And, [Simplified description of the schema] Table 1: The 2x2 curved block implements the visual secret sharing mechanism of the present invention. Figure 1: Schematic diagram of the process of the present invention. Figure 2: 2x2 curved blocks of the four different combinations of the present invention. Figure 3: Hide the second secret in the first _ shared image rotation] 8 degrees in the experimental knot 201126476, (a) the first confidential image, (b) the second confidential image, (c) share the image A, (d) sharing image B, (e) sharing the result of image A and sharing image B, and (f) sharing the result of overlapping image A with image sharing B after 18 degrees.

Figure 4: Hide the results of the second secret in the first shared image rotated 40 degrees, (a) the first confidential image, (b) the second confidential image, (c) share the image A, (d) Share Image B, (e) Share Image A and Share Image B • The result of the overlay, (0 share the result of the image A after 40 degrees and overlap with the shared image B. Figure 5: Hide the second secret on the first Share the experimental results of the image rotation at 72 degrees, (a) the first confidential image, (b) the second confidential image, (c) share the image A, (d) share the image B, (e) share the image A and share As a result of superimposing the image B, (f) sharing the result of superimposing the image A after 72 degrees with the shared image B. • Figure 6: The number of divided regions is not the result of the 4 divisible experiment, (a) the first secret Image, (b) second confidential image, (c) share image A, (d) share image B, (e) share image A and share image B overlap result, (f) share image A to 7 2 degrees The result of superimposing with the shared image B shows that the information displayed in the first area of the second confidential image is wrong. [Main component symbol says Ming] si 1. Color secret image color image Mi 201126476 2. Color secret image color image M2 3. Quantization code 4. Quantization code 5. Index value of color secret image I I, 6. Index value of color secret image called 12 7 . Binary image 0 corresponding to index value I, 8. Binary image corresponding to index value 12 02

9. Share Image A

Share image B

Claims (1)

201126476 seven The scope of application for patents·· ^ ill is divided into parts of the plum; the generation of fine marks in ^ and the image of _ divided droughts (10) produce two major =% of the drought image A production method mainly includes the following steps: The confidential information is converted into a confidential image respectively; Step 2. Perform the generation of the circular shared image A to generate the first shared image. The method for generating the circular drought image B mainly includes the following steps: ^ Hide one. Load two confidential images and a circular shared image A; 0 one's stubborn round sharing image _ drum algorithm to obtain a second share According to the first item of the 5th patent scope of the application, the image is a poor one. Since the 4^- Λ 的 隐 隐 隐 Ϊ Ϊ Ϊ Ϊ Ϊ Ϊ Ϊ 分享 分享 分享 分享 分享 分享 分享 分享 分享 分享 分享 分享 分享 分享 分享Produce Ϊΐ F-sharing algorithm for generating imagesΑ] ^In: two confidential images (^ and 仏; output: circular shared image A; v consumption 1. generating /V absolute is by sharing image A with radius The circle and the radius are the space between the circles of (rrA:xs) and let PUk = PkUPk+i ' Step 2: Cut the household % in units of degree, so that the body contains 360 Curved area; Step 3: For each [S.1 201126476 2x2 curved block in the first area of the corpse (ie, degree to degree), select any 2x2 arc from Figure 4 in a random manner. The block is used to represent; Step 2: Each 2x2 arc in the second area of /3⁄4 (ie X degrees to (2W) degrees) is the phase of the previous area (ie the third area) The corresponding black and white pixels in the 2x2 arc block are defined by the inverse clockwise rotation of 9 degrees; the rest of the regions are deduced by analogy; Step 5: Repeat steps 2 to 4 for each corpse, at each An arc of 2 2x2 arc blocks is generated in /51⁄4; finally, the first shared image A is generated; [Circular shared image B Generated algorithm] ^ Order: two confidential images 〇, 〇 2 and circle share image A; output · circle share image B; Step 1: generate ubiquitous is shared by image b with radius as ab (4) » , the circle and the radius are the space between the circles of (〇jxs) and let CW CkLJCk+i ·, Step 2: Cut the CR in units of degrees, so that the CX4 contains 360 arcs Area; Step 3: According to the shared image A, the first confidential image 〇1 and the second confidential image 〇2, the distribution of each 2x2 arc block in Ci4 is determined together, and the corresponding manner is as shown in Table 1. According to the scope of the patent application No. 2 and Item 2, the present invention can hide two black and white confidential images in two circular shared images. In addition, with color palette and quantization coding technology, The present invention can also hide two color images from 201126476 in two circular shared images.