Controlled alternate quantum walk-based pseudo-random number generator and its application to quantum color image encryption

Pseudo-random number generator (PRNG) are a key component in the design of modern cryptographic mechanisms and are regarded as a backbone element of many modern cryptographic applications. However and in spite of their robustness, quantum computers could crack down PNGR-based systems. Quantum walks, a universal model of quantum computation, have nonlinear properties that make them a robust candidate to produce PRNG. In this paper, we utilize controlled alternate quantum walk (CAQW) to create PRNG. Moreover, we use the presented PRNG mechanism as a component of a new quantum color image encryption protocol. The quantum color image is encrypted via quantum C-Not (controlled-Not) gate which ruled by the key sequence generated from the PRNG mechanism. Simulation results and numerical analyses demonstrate that the suggested PRNG mechanism and its application to quantum color image encryption have high efficiency with high security. (C) 2019 Published by Elsevier B.V.