Implementation of Stronger S-Box for Advanced Encryption Standard

---------------------------------------------------ABSTRACT------------------------------------------------------Advanced Encryption Standard (AES) block cipher system is widely used in cryptographic applications. The main core of AES block cipher is the substitution table or SBox. This S-box is used to provide confusion capability for AES. In addition, to strengthen the S-Box against algebraic attacks, the affine transformation is used. The requirements of information security within an organization have undergone several changes in the last few decades. With the fast evolution of digital data exchange, security of information becomes much important in data storage and transmission. The proposed paper presents a combinational logic based s-box implementation for subBbyte transformation in advanced encryption standard (AES) algorithm in verilog code language, this combinational logic based s-box is small area occupied and provide high throughput .this is a two staged pipelined combinational logic based s-box.the fact that pipelining can be applied to this S-Box implementation as compared to the typical ROM based lookup table implementation which access time is fixed and unbreakable. In this paper, the construction procedure for implementing a 2 stage pipeline combinational logic based S-Box is presented and illustrated in a step-by-step manner.. Finally, for the purpose of practicality, the depth of the mathematics involved has been reduced in order to allow the reader to better understand the internal operations within the S-Box. the simulation and synthesis is done in modelsim and Xilinx software ,output result has been included.