Diffusion-substitution based gray image encryption scheme

In this paper image encryption and decryption using key sequence {K i } generated by sequence {K 1, i } of logistic map and sequence of states {K 2, i } of Linear Feedback Shift Register (LFSR) is proposed Initially one dimensional sequence is generated in the range of 0 to 1 using logistic map for the bifurcation parameter r and initial value X 0  The generated sequences are multiplied with 255 and bit by bit XOR operation employed on states of 8 bit LFSR to obtain final key sequence {K i } So obtained key sequence {K i } is XORed with 8-bit grayscale image pixels {P i } to obtain the encrypted image Performance of the proposed scheme is analyzed by computing Histogram, Entropy, Correlation and MSE (Mean Square Error) between the original and encrypted image This scheme has been tested for two different 8-bit grayscale images of size 256×256 pixels Proposed scheme is compared with encryption/decryption using sequence {K 1, i } generated using logistic map Result of histogram plot of encrypted image using proposed scheme is flat and uniformly distributed compared to encryption scheme using generated sequence of logistic map MSE measured between original and encrypted image found to be high Also correlation between adjacent pixels of encrypted image found to be low

Image encryption and decryption using chaotic key sequence generated by sequence of logistic map and sequence of states of Linear Feedback Shift Register

This paper proposes a chaos-based image encryption scheme where one 3D skew tent map with three control parameters is utilized to generate chaotic orbits applied to scramble the pixel positions while one coupled map lattice is employed to yield random gray value sequences to change the gray values so as to enhance the security. Experimental results have been carried out with detailed analysis to demonstrate that the proposed image encryption scheme possesses large key space to resist brute- force attack and possesses good statistical properties to frustrate statistical analysis attacks. Experiments are also performed to illustrate the robustness against malicious attacks like cropping, noising, JPEG compression. Index Terms—Chaotic system, Coupled map lattice, Ergodicity, 3D skew tent map, Image encryption scheme

/pdf/a-chaos-based-image-encryption-scheme-using-3d-skew-tent-map-23ku85vk6o.pdf

A Chaos-based Image Encryption Scheme Using 3D Skew Tent Map and Coupled Map Lattice

Linear congruential generator has been widely applied to generate pseudo-random numbers successfully. This paper proposes a novel chaos-based image encryption scheme using affine modular maps, which are extensions of linear congruential generators, acting on the unit interval. A permutation process utilizes two affine modular maps to get two index order sequences for the shuffling of image pixel positions, while a diffusion process employs another two affine modular maps to yield two pseudo-random gray value sequences for a two-way diffusion of gray values. Experimental results are carried out with detailed analysis to demonstrate that the proposed image encryption scheme possesses large key space to frustrate brute-force attack efficiently and can resist statistical attack, differential attack, known-plaintext attack as well as chosen-plaintext attack thanks to the yielded gray value sequences in the diffusion process not only being sensitive to the control parameters and initial conditions of the considered chaotic maps, but also strongly depending on the plain-image processed.

/pdf/an-efficient-chaos-based-image-encryption-scheme-using-4tl8x2naky.pdf

An Efficient Chaos-based Image Encryption Scheme Using Affine Modular Maps

In this paper, a generalized multi-sawtooth map based image encryption scheme with an efficient permutation-diffusion mechanism is proposed. In the permutation process, a generalized multi-sawtooth map is utilized to generate one chaotic orbit used to get one index order sequence for the permutation of image pixel positions, while in the diffusion process, two generalized multi-sawtooth maps are employed to yield two pseudo-random grey value sequences for a two-way diffusion of pixel grey values. The yielded grey value sequences are not only sensitive to the control parameters and initial conditions of the considered chaotic maps, but also strongly depend on the plain-image processed, therefore the proposed scheme can effectively resist statistical attack, differential attack, known-plaintext as well as chosen-plaintext attack. Experimental results show that the new image encryption scheme has satisfactory security thanks to its large key space and robust permutation-diffusion mechanism, which makes it a potential candidate for designing image encryption schemes.

A Novel Image Encryption Scheme Based on Generalized Multi-sawtooth Maps

A substitution-diffusion based image cipher using chaotic standard and logistic maps was proposed recently. However, the cipher can be broken with a simple method by using only one known plain and cipher image pair. The attacking process need not to be complex because of the two vital defects of the encryption algorithm. Suggestions for improving the security of the algorithm are also provided.

Qiang Qu

Papers

Cryptanalysis of a Substitution-Diffusion Based Image Cipher Using Chaotic Standard and Logistic Map