VLSI IMPLEMENTATION OF KEY DEPENDENT SUBSTITUTION BOX USING ERROR CONTROL ALGORITHM FOR SUBSTITUTION-PERMUTATION SUPPORTED CRYPTOGRAPHY
B. Senthilkumar, V. Rajamani · 2014
This paper describes about novel VLSI implementation of key based substitution box(S-box) for Substitution-Permutation supported private key cryptosystems. Our design uses the mathematical properties of the (8, 4) Extended Hamming Code and its error control logic to produce 256 unique elements in one Sbox over finite Galois Field (GF) (28). Row – Column Index based selection of four 8bit vectors and their modulo-2 addition is employed for both byte substitution and its inverse. Proposed substitution method provides optimal substitution output probability with 40320 S-boxes for a single message byte over GF (28). Proposed method removes the direct relationship between linear and algebraic expressions of S-box vectors and byte substitution technique of S-box for strengthening our structure against linear and differential attacks. High nonlinearity penetration of original input message bits is achieved by applying shift based key schedules for round transformations and bit permutation based S-box vectors in proposed byte substitution. Proposed design is simulated and synthesized using VHDL coding for Spartan3E FPGA (XC3S500E-PQG208) and the simulation results are shown. Various substitution output results are shown by proposed S-boxes simulation for its optimal application. This paper concludes that novel Key dependent Substitution Box using Error Control Algorithm is an alternative solution to the existing threats on cryptography algorithms.