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Two-Image Encryption by Random Grids. 1. Joy Jo-Yi Chang, Ming- Jheng Li, Yi-Chun Wang and Justie Su-Tzu Juan. National Chi Nan University. B. B. R 1. R 1. R 2. B. R 2. R 1. R 2. B. R 1. R 2. B. R 1. R 2. B. R 1. R 2. random(0,1). random(0,1). B. R 1. R 2. B. R 1.
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Two-Image Encryption by Random Grids 1 Joy Jo-Yi Chang, Ming-Jheng Li, Yi-Chun Wang and Justie Su-Tzu Juan National Chi Nan University
B B R1 R1 R2 B R2 R1 R2 B R1 R2
B R1 R2 B R1 R2 random(0,1) random(0,1) B R1 R2 B R1 R2
Definition 1: fRSP(.): Y ← fRSP(X), Y is the output of the function fRSP(.) with the inputs X, where fRSP(.) is that randomly select a pixel of X. • Definition 2: fRG (.)Y||Z ← fRG (X), Y and Z are the outputs of the function fRG(.) with the input X, where fRG(.) is one of the three random grids algorithm in [6] which inputs a pixel of the secret image, then outputs two cipher-pixels for two shares. X Y Z (i , j) (i , j) (i , j)
Definition 3: (.) :Z← (X,Y): Z , Z is the output of thefunction f’RG(.) with the inputs X and Y, where (.) isthe function according to fRG(.): (as in Definition 2) whichinputs a cipher-pixel of one share Y and a pixel of the secretimage X, then outputs the other cipher-pixel. X Y Z (i , j) (i , j) (i , j)
Chen et al. Step 1: SA(i, j) ← fRSP(SA). Step 2: G1(i, j)||G2(i, j) ← fRG(SA(i, j)). SA G1 G2 Step 3: G2(j,(m-1)-i) ←(SB(j, ,(m-1)-i), G1(i, j)). SB G1 G2
Step 4: G1(j,(m-1)-i) ← (SA(j, (m-1)-i), G2(j, (m-1)-i, ). SA G1 G2 Step 5: G2((m-1)-i, (m-1)-j) ←(SB(j, (m-1)-i), G1(j, (m-1)-i, ). G1 G2 SB
Step 6: G1((m-1)-i, (m-1)-j) ←(SA(m-1)-i, (m-1)-j),G2((m-1)-i, (m-1)-j) SA G1 G2 Step 7: G2((m-1)-j, i) ←(SB(m-1)-i, (m-1)-j),G1((m-1)-i, (m-1)-j), G1 G2 SB
Step 8: G1((m-1)-j, i) ←random(0,1) random(0,1)
This papper SA and SB with the size of 240 ╳240 • Step 1: SA(i, j) ← fRSP(SA). • Step 2: G1(i, j)||G2(i, j) ← fRG(SA(i, j)). (3,4) (3,4) (3,4) SA G1 G2 • Step 3: G2((i + m/4), j) ←(SB(i, j), G1(i, j)). (3,4) (3,4) (63,4) G1 G2 SB
Step 4: G1((i + m/4), j) ←(SA((i + m/4), j), G2((i + m/4),j)). (63,4) (63,4) (63,4) SA G1 G2 • Step 5: G2((i + m/2), j) ← (SB((i + m/4), j), G1((i + m/4),j)). (63,4) (63,4) (123,4) G1 SB G2
Step 6: G1((i + m/2), j) ← (SA((i + m/2), j), G2((i + m/2),j)). (123,4) (123,4) (123,4) SA G1 G2 • Step 7: G2((i + 3m/4), j) ← (SB((i + m/2), j), G1((i + m/2),j)). (123,4) (183,4) (123,4) SB G1 G2
Step 8: G1((i + 3m/4), j) ← (SA((i + 3m/4), j), G2((i +3m/4), j)). (183,4) (183,4) (183,4) SA G1 G2
Simulation 2: binary secrets, moving horizontally by 1/8 width. share G1 share G2 Simulation 1: binary secrets, moving horizontally by 1/4 width. share G1 share G2
Simulation 4: no constraint about the size. share G1 share G2 Simulation 3: binary secrets, moving horizontally by 1/30 width. share G1 share G2
THE COMPARISON OF THE SIZE. QUANTITY OF THE DISTORTION