Rhouma Rhouma

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In this paper, we propose to cryptanalyse an encryption algorithm which combines a DNA addition and a chaotic map to encrypt a gray scale image. Our contribution consists on, at first, demonstrating that the algorithm, as it is described, is non-invertible, which means that the receiver cannot decrypt the ciphered image even if he posses the secret key.(More)
The paper proposes breaks for the permutation methods adopted in the chaos-based image cryptosystems. By a careful examination on the most chaotic image cryptosystems we can find that the permutation process constitute the main step or, in some cases, the only step to create the confusion. It can be applied on the pixels or on the pixel bits. A recently(More)
In this paper, a novel steganographic scheme is proposed based on chaotic map in the DCT domain. The proposed method apply the DCT on the cover image, scan the AC coefficients in a zigzag form from the least significant to the most significant one, this scan will lead us eventually to precise the embedding positions through a chaotic function as well as the(More)
This paper presents a very simple and efficient encryption scheme based on controlled chaotic maps and ADPCM (Adaptive Differential Pulse Code Modulation) coding, in order to secure the real-time voice communication for operating at 16, 24, 32 or 40 kbps. This encryption algorithm adopts three main operations one to generate chaotic values using two chaotic(More)
We propose to incorporate encryption procedure into the lossy compression of voice data PCM(Pulse Code Modulation) based on the A-law approximation quantization. The proposed codec CPCM (Chaotic Pulse Code Modulaion) will join the encryption to the compression of the voice data. This scheme provides the same compression ratio given by the PCM codec, but(More)
In this paper, we propose to enhance a recently proposed image cryptosystem based on hyper-chaos. The updated version has been builded to resist against attacks made to break the original one and to make it faster. The modification touch on the two Boxes, P-Box and S-Box, which composed the original cryptosystem. Compared with classical encryption scheme,(More)
We report a break for a recently proposed class of cryptosystems. The cryp-tosystem uses constant points of a periodic secret orbit to encrypt the plain-text. In order to break the system, it suffices to sort the constant points and find the initial fixed point. We also report breaks for the modified versions of the cryptosystem. Besides, we discuss some(More)