Design a Compact Nonlinear SBox with MultipleAffine Transformations The present paper introduces a new method of SBox construction which work as a byteoriented substitution scheme. The SBox design considers the core part for the building most block cipher algorithms and play a major role in generating confusion property. Modern ciphers build with different types of SBox of halfbyte (nibble of 4bit) or fullbyte 8bit as lookup tables with distinct mathematical Boolean functions (BFs). The proposed method generates the Sbox based on multiplications of multiple different affine transforms with multiple distinct overlapped vectors of 8bit to achieve high nonlinearity. The construction of Sbox focused on use an irreducible polynomial of order eight over Galois Field GF (28). The proposed Sbox quit similar to the Sbox of Advance Encryption Standard (AES) but with more algebraic complexity and high nonlinearity factor.

An Efficient Cryptosystem based on the LogisticChebyshev Map We utilise the LogisticChebyshev map as a cascade discretetime chaotic system to design a new form of a cryptosystem. Based on the LogisticChebyshev map, we present a novel method for constructing substitution boxes or Sboxes. The performance of the proposed Sbox scheme is investigated. Our results shows that the constructed Sbox has significant qualities for viable applications in security related domains. Additionally, we utilise a new pseudorandom number generator (PRNG) scheme for the purpose of generating keystreams for further encryption. We utilise this technique to demonstrate how a PRNG based chaotic system can be utilsied for image encryption. Our simulation results and analysis show that the proposed scheme has efficient performance for cryptographic based image processing applications.