Fast and Secure Chaos-Based Cryptosystem for Images

Abstract

Nonlinear dynamic cryptosystems or chaos-based cryptosystems have been attracting a large amount of research since 1990. The critical aspect of cryptography is to face the growth of communication and to achieve the design of fast and secure cryptosystems. In this paper, we introduce three versions of a chaos-based cryptosystem based on a similar structure of the Zhang and Fridrich cryptosystems. Each version is composed of two layers: a confusion layer and a diffusion layer. The confusion layer is achieved by using a modified 2-D cat map to overcome the fixed-point problem and some other weaknesses, and also to increase the dynamic key space. The 32-bit logistic map is used as a diffusion layer for the first version, which is more robust than using it in 8-bit. In the other versions, the logistic map is replaced by a modified Finite Skew Tent Map (FSTM) for three reasons: to increase the nonlinearity properties of the diffusion layer, to overcome the fixed-point problem, and to increase the dynamic key space. Finally, all versions of the proposed cryptosystem are more resistant against known attacks and faster than Zhang cryptosystems. Moreover, the dynamic key space is much larger than the one used in Zhang cryptosystems. Performance and security analysis prove that the proposed cryptosystems are suitable for securing real-time applications.

Real-time selective video encryption based on the chaos system in scalable HEVC extension

“…The encryption scheme SE-SHVC-BL considerably decreases the objective quality of both layers since the inter-layer prediction used in the SHVC extension propagates 4 Optimized software refers in this paper to a code-source written in Single Instruction Multiple Data (SIMD) operations. 12 13 errors, introduced by encryption, from the encrypted BL to the clear (non-encrypted) EL. In fact, the EL decoder uses reconstructed samples of the BL picture as a reference for inter-layer prediction and also uses the encrypted BL MVs in the inter-layer merge mode 5 .…”

“…On the other hand, security and confidentiality of multimedia contents have become a challenging research topic. They have been widely investigated in the last 1 *Manuscript 2 decade by using standard cryptography [9][10][11], and chaos-based cryptography [12,13]. Indeed, a variety of chaosbased crypto-systems have been investigated and most of them are based on the structure of Fridrich, which is based on the traditional confusion-diffusion architecture proposed by Shannon.…”

Geração de Sequências Pseudo-Aleatórias Baseadas no Mapa de Arnold Discreto Sobre Zn

“…O mapa de Arnoldé utilizado frequentemente em aplicações de segurança de imagens, como por exemplo em cifragem [17] e em marca d'água [18], poisé conveniente aplicar mapas bidimensionais nos pixels que compõem uma imagem. Este mapaé apresentado originalmente com a sua ação sobre a imagem de um gato [15], mostrando que ele gera um comportamento de stretching e squeezing [19] sobre esta, similarmente ao comportamento do conhecido mapa da ferradura de Smale [20].…”

“…O período máximo das sequências {z n } geradas por Γ vé o triplo das sequências geradas por Γ d . Utilizando a condição inicial (x 0 , y 0 ) = (1, 2) e N = 3 3 , a sequência {z n } gerada pelo mapa Γ v de período 54é {2,12,16,22,18,23, 26,18,1,19,21,17,23,15,13,16,15,11,20,12, 25,13,18,5,17,18,10,10,21, 26,14,15,22,7,15,20,11,12,7,4,18,14,8,18,19,1,21,8,5,15,4, 25,15,2,2,12,…”

A Novel Quasigroup Substitution Scheme for Chaos Based Image Encryption

“…Hence the cryptosystems based on chaotic systems mainly suffer from key size requirements [Alvarez & Li, 2006, Kelber & Schwarz, 2007, Rhouma et al, 2010, Solak et al, 2010, Ozkaynak and Ozer, 2016. Despite above mentioned drawback of having a reduced key space, the chaotic systems have been a preferred choice [Patidar et al, 2011, Wang and Xu, 2015, Wu et al, 2016, Abd-El-Hafiz et al, 2016, Farajallah et al, 2016 for the image encryption systems due to their features: ergodicity, mixing property, sensitivity to initial conditions/system parameters, etc. having close resemblance with the ideal cryptographic properties: confusion, diffusion, balance, avalanche properties, etc.…”