Color image encryption scheme using coupled hyper chaotic system with multiple impulse injections

The paper proposes a color image encryption scheme based on coupled hyper chaotic Lorenz systems. The novelty is to randomly inject impulse signals into coupled Lorenz system during iterations to enhance the complexity of trajectory. Six state variables sequences are generated to encrypt the red, green and blue components by bitwise operations of exclusive or (XOR) and left or right cyclic shift. Six initial values and indeterminate multiple impulse signals can make the cryptosystem own larger variable key space to resist against exhaustive attack, even the attack from quantum computer. Simulation results show that the mean encryption speed is stable, which means the speed depends solely upon hardware equipment and algorithm. Statistical analysis demonstrates the high effectiveness of the proposed image encryption algorithm.