An elliptic curve-based approach for enhanced security of substitution-permutation networks

A well-designed substitution-permutation network (SPN) relies on several interspersed rounds of S-boxes and P-boxes, fulfilling the properties of Shannon’s confusion and diffusion. In any SPN, the role of the confusion constituent, S-box, is essentially decisive as one-bit change in the key leads to the change in several of the round keys. Consequentially, every round key spreads out over all the bits, changing the ciphertext in an absolutely complex manner. The unpredictable advancement of secured cryptographic systems escorts an indispensable demand to develop new S-box generators, offering optimized security features on a reduced computational cost. It has been established that the use of elliptic curves in cryptography offers elevated security with a reduced key size. In the proposed work, we deploy high resistance of elliptic curves’ point addition system against modern cryptanalysis, to evolve a substitution algorithm. Precisely, we use the complex algebraic structure of an elliptic curve group over a finite field. Our novel approach reduces the computational labor just by utilizing the nonlinear point-addition mechanism to design a substitution algorithm. The idea is supported through a step by step illustration of problem formulation. The outcomes of the proposed algorithm are judged through all the fundamental evaluation parameters and a comprehensive analysis including comparison with some recent techniques is also presented that proves the effectiveness of our model.