Breaking and improving an image encryption scheme based on total shuffling scheme

This paper proposes breaks for the total shuffling scheme adopted in the skew tent-map-based image cryptosystem. By applying chosen plaintext combined with chosen ciphertext attack, we demonstrate that a hacker can determine the permutation vector and the whole random code sequence used respectively in permutation and diffusion procedure, which can be exploited to reveal the plain image. Then we proposed an improved algorithm based on the skew tent map. The theoretical analysis and experimental results indicate that the improved algorithm can overcome these flaws and has better cryptographic performances in resisting against chosen plaintext and chosen ciphertext attacks, randomness, and sensitivity.