Amalgamation of Cyclic Bit Operation in SD-EI Image Encryption Method: An Advanced Version of SD-EI Method: SD-EI Ver-2

In this paper, the author presents an advanced version of image encryption technique, which is itself an upgraded version of SD-EI image encryption method. In this new method, SD-EI Ver-2, there are more bit wise manipulations compared to original SD-EI method. The proposed method consist of three stages: 1) First, a number is generated from the password and each pixel of the image is converted to its equivalent eight binary number, and in that eight bit number, the number of bits, which are equal to the length of the number generated from the password, are rotated and reversed; 2) In second stage, extended hill cipher technique is applied by using involutory matrix, which is generated by same password used in second stage of encryption to make it more secure; 3) In last stage, we perform modified Cyclic Bit manipulation. First, the pixel values are again converted to their 8 bit binary format. Then 8 consecutive pixels are chosen and a 8X8 matrix is formed out of these 8 bit 8 pixels. After that, matrix cyclic operation is performed randomized number of times, which is again dependent on the password provided for encryption. After the generation of new 8 bit value of pixels, they are again converted to their decimal format and the new value is written in place of the old pixel value. SD-EI Ver-2 has been tested on different image files and the results were very satisfactory.