Image encryption plays an essential role in the community of image security. Most existing approaches adopt a permutation–diffusion scheme to permute pixel positions and change values separately. One limitation this is that it has high risk being cracked. To solve problem, we propose approach jointly permutates diffuses (JPD) pixels color for encryption. First, 4D hyperchaotic system with two p...

In this paper, a kind of two-dimensional coupled chaotic transcendental map (TCCTM) was proposed. Firstly, by using the TCCTM chaotic sequences were generated,then the chaotic sequences were modified to generate chaotic key stream that is more suitable for image encryption. In the process of encryption, an original color image was decomposed into three images of red, green and blue components, ...

Image encryption is a crucial area for researchers in information security, which protects digital images from unauthorized access. This paper proposes novel image scheme based on the multi-chaotic system. about encrypting color 2D Henon map and 3D Lorenz map. We used equation to generate new S-Box, thus creating solid cipher that difficult break (for confusion operation). then keys shifting pr...

Visual cryptography (VC) technique encodes an image into two or more shares that appear random in human eyes. In the decryption section, pixels shared images are combined to obtain information contained original image. This study applies visual cryptographic techniques graysle and color for user authentication online transactions using VC2,2 scheme. The server computer CAPTCHA sent through diff...

In this paper, the quaternion discrete Cosine transform (QDCT) is applied to the color image encryption technology, and partial encryption technique of color image based on QDCT is proposed. Obtained the QDCT spectrum of color image by QDCT, the real and imaginary parts of QDCT coefficients are quantized and encoded with the color image quantization coefficient table and QDCT coefficients encod...

image retrieval is an important research field which has received great attention in the last decades. in this paper, we present an approach for the image retrieval based on the combination of text-based and content-based features. for text-based features, keywords and for content-based features, color and texture features have been used. query in this system contains some keywords and an input...