Hossam Ahmed

Encryption quality analysis of the RC5 block cipher algorithm for digital images

We investigate the implementation and application of the RC5 block cipher algorithm for digital images and provide testing, verification, and encryption efficiency of the RC5 block cipher for digital images. We describe briefly the basic design parameters of the RC5 block cipher and its implementation for digital images. A complete specification for the method of application of the RC5 block cipher to digital images is given. Several test images are used for inspecting the validity of the encryption and decryption algorithms. Also, we provide and introduce a mathemati- cal measure for encryption efficiency, which we will call the encryption quality instead of visual inspection, and apply it to several images. The encryption quality of the RC5 block cipher algorithm is investigated along its several design parameters, such as word size, number of rounds, and secret key length, and the optimal choices for the best values of these design parameters are given.

Image Encryption Based on Development of Hénon Chaotic Maps using Fractional Fourier Transform

In this paper, the authors propose an image encryption scheme based on the development of a Henon chaotic map using fractional Fourier transform FRFT which is introduced to satisfy the necessity of high secure image. This proposed algorithm combines the main advantages of confusion and diffusion with FRFT, it use Arnold Cat map for confusion and Henon chaotic map or one of the proposed Henon chaotic maps for diffusion. The proposed algorithm is compared with some image encryption algorithms based on Arnold Cat map, Baker chaotic map, Henon chaotic map and RC6. The authors perform a comparison between them in several experimental tests as statistical analyses, processing time and security analysis. The authors find from these comparison tests that the proposed algorithm demonstrates good result even better than RC6 and other chaotic maps in some cases.

Orthogonal Frequency Division Multiplexing

Orthogonal frequency division multiplexing (OFDM) is a method of modulation of digital signal in which a signal is divided into many narrowband channels of different frequencies. This technology was first used in the 1960s for the research to minimize interference between channels which are near to each other with respect to frequency. In some points, OFDM and Frequency Division Multiplexing (FDM) are similar to each other. They differ from each other in modulation and demodulation technique of the signal. But in both the cases minimization of the interference, or crosstalk between the channels and symbols forming data stream is given priority and perfection of individual channels is given less importance.OFDM technology is used in European digital audio broadcast services. This technology is also used in digital television and is now being considered as a technique of receiving high-speed digital data over the same conventional telephone lines.