TWI448133B - Method of cryptographic communications by using sand-texture images - Google Patents

Description

Sandy image communication encryption and decryption method

The invention belongs to a method for encrypting and decrypting using sand image communication. More specifically, the present invention selects a background image, and a two-grain image is associated with a shift table by a periodic table, so that a sand image is input into a plain image, that is, a ciphertext map can be formed. For example, and inputting the ciphertext image in another sand image, the plain image and the background image can be displayed.

The patent application filed by the applicant is referred to the previous invention application: "Multilayer diffusion stream encryption and decryption method and configuration", application No. 99112624 (hereinafter referred to as the reference case), submitted on April 22, 1999, the reference case A maximum number of cycles is formed by a plurality of diffusion functions A F( p ₁ , p ₂ , ... p _k ), and the corresponding plurality of positions are p ₁ , p ₂ , ... p _{k , respectively} .

The invention generates a periodic table and a shift table by using the diffusion function of the reference case, and generates a sand image by using the numerical distribution of the periodic table and the shift value of the shift table; in contrast, the early sand image is applied to the visual password, Emphasis on the use of visual effects, in a halftone way, the image is disassembled into two sand-grained pictures, which are guided by the visual effect technology, which is different from the present invention.

The invention is applied to the communication of sand image, which generates a periodic table of all values (excluding 0) of n bits in a maximum cycle period, and generates a shift table suitable for any periodic table, with the shift table At least one shift value, such that a background image can correspond to two sand image; when a plain image is input to a sand image, a ciphertext image can be formed, and another sand image is formed. Entering the ciphertext image, the plaintext image and the background image can be displayed, and the steps of encrypting and decrypting are as follows:

(A) Produce a sand image im 1 and im 2:

(a) selecting a background image im , a periodic table Tp , a shift table Ts ;

(b) taking at least a shift value Ts Ts (i _*), found in the corresponding Tp im im to im. 1 and 2;

(B) Obtain a ciphertext image ime :

(a) input a plain text, the plaintext is converted into an image imx ;

(b) Perform the encryption operation of the bit XOR, ime = imx ⊕ im 1;

(C) displaying the plaintext and the background image imd ;

(a) input the ciphertext ime ;

(b) Perform the decryption operation of the bit XOR, imd = ime ⊕ im 2.

The first figure shows a schematic flow diagram of the present invention, which includes the steps of: initiating communication between a transmitting end 10a and a receiving end 10b ; the transmitting end generates a sand image 20a , and the receiving end generates a paired sand image 20b The transmitting end inputs a plaintext image 30a , and the plaintext image and the sandographic image performing bit XOR generate a ciphertext image 40a ; the receiving end receives the ciphertext image 30b of the transmitting end, and the The ciphertext image and the paired shading image execution bit XOR display the plaintext image 40b .

Furthermore, from the background image of the plain text displayed in the first FIG. 40b , the corresponding value of the background image is found by selecting at least one shift value of the periodic table and the shift table, that is, the sand is decomposed into the transmitting end. The image password 20a is paired with the sand image of the receiving end with the password 20b ; therefore, the generation of the image passwords of both parties can be produced by the third party and then sent to both parties respectively, or the background image and periodic table are agreed by both parties. The shift values are generated separately.

Symbols and definitions: According to page 5 of the reference:

● A : a diffusion region, the A contains an initial value A ⁰ , and is an m- dimensional bit matrix of d ₁ × d ₂ ×...× d _m whose position is indicated by 1 to n , and its bit value is a ₁ to a _n .

● A F( p ₁ , p ₂ ,..., p _k ): This A performs a complex number of diffusion functions F( p ₁ , p ₂ ,..., p _k ) whose specified positions are respectively p ₁ , p ₂ ,..., p _k .

● : The A performs a diffusion mechanism , which is Abbreviation, which means that F( p ₁ , p ₂ ,..., p _k ) is repeatedly executed t ₁ times.

The case is added as follows:

● Tp : a period table, the Tp = [ A , A F ¹ , A F ² , A F ³ ,..., ].

● Tp (i): Tp value of the i th position, such as ^{Tp (3) = A F 2} .

● Tp _i : Tp moves the periodic table of i bits, such as Tp ₁ =[ , A , A F ¹ , A F ² ,..., ].

● Tp _{< k >} : Tp _{< k >} = Tp ⊕ Tp _k ; In the two periodic tables, the value of the same position performs the bit XOR.

● Ts : a shift table, which is Ts = [<1>, <2>, <3>, ..., <2 ⁿ -2>].

● Ts (i): Ts value of the i-th position as Ts (3) = <3> .

Periodic table production:

The periodic table of this case will contain all the values (excluding 0), that is, 2 ⁿ -1 values; assuming A is a 1x5-bit matrix, F(1,3,4,2,5) is executed, and when the A value is 15 (ie [01111]), and then on the fifth page of the reference case, the output value of A F ¹ is 4 (ie [00100]), and the calculation is as follows:

A ⁰ F( p )= A ⁰ ⊕ A ⁰ y _p ⊕ S ; ( assume S =0)

A ⁰ F(1)=[01111]⊕[00111]=[01000];

A ⁰ F(1,3)=[01000]⊕[10000]=[11000];

A ⁰ F(1,3,4)=[11000⊕[10000]=[01000];

A ⁰ F(1,3,4,2)=[01000]⊕[10100]=[11100];

A ⁰ F(1,3,2,4,5)=[11100]]⊕[11000]=[00100];

According to the above calculation, let the initial value of A be 1, and then the periodic table of F(1,3,4,2,5) mechanism, all the values are arranged as [1,3,15,4,25,5,26, 10,30,19,27,9,17,23,2,12,11,29,28,31,16,20,13,8,18,24,6,21,14,7,22]; same Ground, with the periodic table of F(5,3,2,4,1) mechanism, all the values are arranged as [1,5,22,2,9,3,12,21,14,28,13,16, 24,30,4,19,20,11,10,15,25,27,18,17,29,8,6,26,23,7,31]. Furthermore, with F(1,5,3,2,4), F(5,1,3,4,2), F(2,4,1,5,3), F(4,2,5 ,1,3),F(2,5,1,3,4), F(4,1,5,3,2), F(3,2,4,1,5),F(4,1 , 5, 3, 2), can get a periodic table of all values.

The process of making a periodic table Tp , as shown in the third figure, includes the following steps:

1. Select a diffusion region A , a diffusion mechanism ;

2. A A sets the initial value of ^0;

3. Set a variable t ₂ =1;

4. Execution Achieved A new value ;

5. Store the A value in order to the periodic table;

6. t ₂ = t ₂ +1, if t ₂ < 2 ⁿ , go back to step 4.

Shift table production:

The shift table of this case is applicable to any periodic table ( Tp ), which will correspond any value in the periodic table to two values, that is, the background image is decomposed into two sand images; in the production of the shift table, A periodic table can be selected. Assuming that A is a 1x5-bit matrix, the periodic table of F(1,3,4,2,5) is derived as follows:

Tp = [1,3,15,4,25,5,26,10,30,19,27,9,17,23,2,12,11,29,28,31,16,20,13,8 ,18,24,6,21,14,7,22]

Tp ₁ = [22,1,3,15,4,25,5,26,10,30,19,27,9,17,23,2,12,11,29,28,31,16,20, 13,8,18,24,6,21,14,7]

Tp _<1> = Tp ⊕ Tp ₁

=[23,2,12,11,29,28,31,16,20,13,8,18,24,6,21,14,7,22,1,3,15,4,25,5, 26,10,30,19,27,9,17]

From the above derivation results, it can be known that Tp _<1> = Tp ⊕ Tp ₁ = Tp ₁₈ , that is, the periodic table moves 18 positions, therefore, the shift table Ts (1)=<1>=18 is derived; Such a push,

Tp = [1,3,15,4,25,5,26,10,30,19,27,9,17,23,2,12,11,29,28,31,16,20,13,8 ,18,24,6,21,14,7,22]

Tp ₂ =[7,22,1,3,15,4,25,5,26,10,30,19,27,9,17,23,2,12,11,29,28,31,16, 20,13,8,18,24,6,21,14]

Tp _<1> = Tp ⊕ Tp ₁

=[6,21,14,7,22,1,3,15,4,25,5,26,10,30,19,27,9,17,23,2,12,11,29,28, 31,16,20,13,8,18,24]

The periodic table moves 5 positions, and it is found that Tp _<2> = Tp ⊕ Tp ₂ = Tp ₅ , Ts (2) = <2> = 5; finally, derive Ts = [18, 5, 29, 10, 2, 27,22,20,16,4,19,23,14,13,24,9,30,1,11,8,25,7,12,15,21,28,6,26,3,17] .

The flow of a shift table Ts , as shown in the fourth figure, includes the following steps:

1. Select a periodic table Tp ;

2. Set a variable k =1;

3. Find Tp _<k> = Tp ⊕ Tp _k and get the < k >value;

4. Store the < k > value in sequence to the shift table;

5. k = k +1, if k < 2 ⁿ -1, go back to step 3.

Sand grain image production:

Applying a background image ( im ), a periodic table ( Tp ), and a shift table ( Ts ), it can be easily decomposed into two sand images, where a sand image ( im 1 ) uses Ts ( i ) ), a paired sand image ( im 2) must use Ts (2 ⁿ -1- i ); assuming n = 5 bits processing, for example:

Im =[6,6,7,25,25,25,10,11]

Ts = [18,5,29,10,2,27,22,20,16,4,19,23,14,13,24,9,30,1,11,8,25,7,12,15 ,21,28,6,26,3,17]

Tp = [1,3,15,4,25,5,26,10,30,19,27,9,17,23,2,12,11,29,28,31,16,20,13,8 ,18,24,6,21,14,7,22]

Start to take im (1) = im (2) = 6, find Tp (27) = 6, remove 27, set im 1 with Ts (3) = 29, then im 2 must use Ts (28) = 26; in im Part of 1: (27+29) mod 31=25, Tp (25)=18, ie im 1(1)= im 1(2)=18, in the part of im 2: (27+26) mod 31= 22, Tp (22) = 20, that is, im 2 (1) = im 2 (2) = 20, where 31 represents 2 ⁿ -1.

In order, take im (3)=7, find Tp (30)=7, take out 30, in the part of im 1: (30+29) mod 31=28, Tp (28)=21, ie im 1( 3) = 21, in the part of im 2: (30 + 26) mod 31 = 25, Tp (25) = 18, ie im 2 (3) = 18, and finally, im 1 = [18, 18, 21, 15 , 15, 15, 5, 2], im 2 = [20, 20, 18, 22, 22, 22, 15, 9], complete the disassembly of the background image.

In terms of security considerations, the order of at least one Ts ( i _* ) is adopted, and i _{* is} from 3 to 10. Then, the im T 1 ( i _* ) is [29, 10, 2, 27). , 22, 20, 16, 4], and the im T 2 (2 ⁿ -1- i _* ) is [26,6,28,21,15,12,7,25], when the im ( 1) = 6, im 1 with Ts (3) = 29, im 2 with Ts (28) = 26, as above, im 1 (1) = 18, im 2 (1) = 20; when extracting im (2) =6, find Tp (27)=6, take 27, im 1 with Ts (4)=10, im 2 with Ts (27)=6, in im 1 part: (27+10) mod 31=6, Tp (6)=5, ie im 1(2)=5, in the part of im 2: (27+6) mod 31=2, Tp (2)=3, ie im 2(2)=3; Take im ( i ) and use Ts ( i ) in order to get im 1=[18,5,1,1,6,18,8,16], im 2=[20,3,6,24,31 , 11, 2, 27].

The flow of sand pattern production in this case, as shown in the second figure, includes the following steps:

1. Select a background image im , a periodic table Tp , a shift table Ts ;

2. Set at least one Ts ( i _* ), which is in the order of i ₁ , i ₂ ,..., i _k ;

3. Set a variable i =1;

4. Find Tp ( p _i )= im ( i ) and get the position p _i ;

5. A sand pattern image: im 1( i )= Tp ((( p _i + Ts ( i _* )) mod(2 ⁿ -1));

A paired sand image: im 2( i )= Tp ((( p _i + Ts (2 ⁿ -1- i _* )) mod(2 ⁿ -1));

6. i = i +1, go back to step 4 until you finish reading im .

Preferred Embodiment A:

In the image processing of a computer, whether it is a grayscale or a color format, a byte is used as a basic unit. Therefore, the preferred embodiment proposes an 8-bit processing unit. And, the specific values of the fifth to seventh charts are listed (from left to right, top to bottom, in order) to provide a reference for the skilled person as a practical application.

First, a periodic table Tp must be created. As shown in the third figure, F ¹ =F(7,8,6,5,4,3,2,1) 211 , A ⁰ =1 212 , and then cooperate with the flow chart. And refer to the example of the periodic table production to obtain the periodic table Tp (fifth figure); further, create a shift table Ts , as shown in the fourth figure, select a periodic table (set the fifth figure) 221 , The shift table Ts (sixth figure) can be obtained by cooperating with the flowchart and the example of the shift table creation .

According to the second figure, a periodic table Tp 210 is selected , and after a shift table Ts 220 , a sand grain image is started; a background image im 201 of 47×149 size is input, and im is displayed in the seventh figure A. 11 columns, the 8-bit value in column 1-128, next, set the i _* value of Ts ( i _* ) from 60 to 80, that is, Ts ( i _* ) is sequentially [47, 28, 18, ..., 7,197] 202 .

When reading the first position of the seventh A picture, it indicates that i = 1491 207 , im (11, 1) = 251, find Tp (195) = 251, p _i = 195 204 , in the im 1 (11, 1) part , It is inferred that Ts ( i _* ) has been recycled to the 21st position of the 71st time Ts (80) = 197, (195 + 197) mod 255 = 137, im 1 (11, 1) = Tp (137) = 179 205 , the result corresponds to the first position of the seventh B map; in the im 2 (11,1) part, Ts (255- i _* ) is sequentially [242, 222, 211, ..., 183, 117], taking the 21st position Ts ( 175)=117, (195+117) mod 255=57, im 2(11,1)= Tp (57)=72 206 , and the result corresponds to the first position of the seventh C-picture.

Finally, according to the first figure, the transmitting end generates a sand image im 1 20a , and the receiving end generates a paired sand image im 2 20b ; when encrypting, a plaintext image and an im 1 performing bit XOR are generated. a ciphertext image ime 40a , in the seventh D image shows the ime in the 11th column, the 8-bit value in the 1-128 column; when decrypted, im 2 and ime perform the bit XOR, the plaintext and the Background image 40b.

Preferred Embodiment B:

The invention can be extended to a plurality of transmitting ends, and a plurality of receiving ends communicate; according to the ninth figure, the preferred embodiment provides a simple description by two transmitting ends, and the two receiving ends provide a simple description; At the end of the message, the receiving end shares a sand image, and the transmission end uses different sand images for security reasons. Therefore, in this example, three sand images are generated.

From the above example, the sand image im 1 and im 2 have been generated. In this case, im 1 or im 2 can be regarded as a background image, and Tp and Ts ( i _* ) are set as in the above example, and the second image is executed. 205 , 206 , you can produce two combinations ( im 1, im 3, im 4) or ( im 2, im 3, im 4).

In this example, im 2 is used as a background image, and another periodic table Tp is selected. As shown in the eighth figure, F ¹ =F(3,4,5,6,7,8,2,1), and then Change the i _* value of Ts ( i _* ) from 40 to 50, and 2 ⁿ -1- i _{* to} 215 to 205, Ts ( i _* )=[226,178,...,218,251], Ts (2 ⁿ - _{1- i *) = [186,137,} ..., 169,201], which performs second 205, 206, broken down into the im 2 im 3 and im 4.

Finally, according to the ninth figure, S1 inputs a plaintext image, and XOR with im 1 bit, generates a ciphertext image ime 1, S2 inputs a plaintext image, and XOR with im 3 bits, generates one The ciphertext image ime 2; and in R1 and R2 , input ime 1, ime 2, and ime 1⊕ ime 2⊕ im 4, the result will display the original background image and the message sent by the two transmitting ends.

Although the present case is illustrated by several preferred embodiments, those skilled in the art can make various forms of changes without departing from the spirit and scope of the case. The above embodiments are only used to illustrate the present case and are not intended to limit the scope of the present invention. All kinds of modifications or changes that are not in violation of the spirit of the case are the scope of patent application in this case.

The first figure is a schematic flow chart of an encryption and decryption method using sand image communication according to the present invention;

The second figure is a schematic flow chart of the sand image generated by the present invention;

The third figure is a schematic diagram of the process of making the periodic table of the present invention;

The fourth figure is a schematic flow chart of the production of the shift table of the present invention;

The fifth figure is a diagram of all numerical distributions of the octet table of the present invention with F ¹ =F(7,8,6,5,4,3,2,1);

Figure 6 is a diagram showing the distribution of all shift values of the octet shift table of the present invention;

Figure 7A is a numerical diagram of a background image im (11, 1~128) of a preferred embodiment A of the present invention;

Figure 7B is a numerical diagram of the sand image im 1 (11, 1~128) of the preferred embodiment A of the present invention;

Figure 7 is a numerical diagram of a sand image im 2 (11, 1~128) of a preferred embodiment A of the present invention;

7D is a numerical diagram of a ciphertext image ime (11, 1~128) of a preferred embodiment A of the present invention;

The eighth figure is a diagram of all numerical distributions of the octet table of the present invention with F ¹ =F(3,4,5,6,7,8,,,1);

The ninth figure is a schematic diagram of a structure of a plurality of people using sand pattern communication according to a preferred embodiment of the present invention.

Claims (10)

An encryption and decryption method using sand image communication, the method uses n bits as an operation unit, and includes the following steps: (A) generating a sand image im 1 and im 2: (a) selecting a background image im, a Tp of the periodic table, a shift table Ts; (B) to take at least a shift value Ts Ts (i _*), to find the Tp corresponding to im im. 1 and im 2; (B) obtaining a ciphertext FIG. Like ime : (a) enter a plaintext, the plaintext is converted to an image imx ; (b) perform a bitwise XOR encryption operation, ime = imx ⊕ im 1; (C) display the plaintext and the background image imd :( a) input the ciphertext image ime ; (b) perform the decryption operation of the bit XOR, imd = ime ⊕ im 2. According to the method of claim 1, wherein, in communication, a transmitting end and a receiving end are selected; the transmitting end performs step (B), and the receiving end performs step (C). According to the method of claim 1, wherein the step (A) is performed by selecting at least one sand image as a background image in a continuous manner, and a plurality of sand patterns are generated in total; a plurality of sand-grain images - a number of transmission ends, at least one receiving end; from the configuration of the plurality of sand-grain images, each of the transmitting ends respectively obtains a sand image execution step (B), Each receiving end jointly obtains only one sand image execution step (C). According to the method of claim 1, wherein, in the communication, a third party is selected; and the third party performs step (A). The method according to claim 2, wherein the im 1 of the step (B) can be generated by the transmitting end, and the im 2 of the step (C) can be generated by the receiving end. According to the method of claim 3, wherein each time step (A) is performed, a periodic table may be selected. The method of claim 3, wherein each step (A) is performed, optionally at least one shift value. According to the method of claim 1, wherein the step (A) generates the periodic table Tp , which comprises the following steps: (a) selecting a diffusion region A , a diffusion mechanism ; Initial value A ⁰ (b) A set of; (c) setting a variable t ₂ = 1; (d) performing Achieved A new value (e) sequentially store the A value to the periodic table; (f) t ₂ = t ₂ +1, and if t ₂ < 2 ⁿ , return to step (d). According to the method of claim 1, wherein the step (A) generates the shift table Ts , which comprises the steps of: (a) selecting a periodic table Tp ; (b) setting a variable k =1; (c) find Tp _{< k >} = Tp ⊕ Tp _k , obtain the < k >value; (d) store the < k > value sequentially to the shift table; (e) k = k +1 if k < 2 ⁿ -1, return to step (c). The method of claim 1, wherein the step (A) generates the sand image im 1 and im 2, comprising the steps of: (a) the at least one Ts ( i _* ), i _* indicates that the position is i ₁ , i ₂ , ..., i _k ; (b) set a variable i =1; (c) find Tp ( p _i ) = im ( i ), obtain position p _i ; (d) Im 1( i )= Tp ((( p _i + Ts ( i _* )) mod(2 ⁿ -1)); im 2( i )= Tp ((( p _i + Ts (2 ⁿ -1- i _* )) mod(2 ⁿ -1)); (e) i = i +1, return to step (c) until im is finished.