Chaos-based color pathological image encryption scheme using one-time keys

This paper proposes an improved chaos-based color pathological image encryption algorithm, using SHA-2 to generate one-time keys. In order to send different ciphered images to different recipients, the hash value of the plain image and a random number are applied to generate one-time initial conditions for Chebyshev maps, to make the key stream change in every confusion process without changing the common initial values. The permuted image is divided into 256-bit long blocks, the avalanche effect is applied to diffuse the blocks, i.e., each block is XORed with the hash value of the prior block. Simulation results demonstrate that the proposed algorithm is robust against common attacks.