Analysis and improvement of a chaos-based symmetric image encryption scheme using a bit-level permutation

Recently, a chaos-based symmetric image encryption scheme using a bit-level permutation was proposed. In this paper, we analyze the potential flaws in Zhu's algorithm in detail and develop a chosen-plaintext attack and chosen-ciphertext attack on Zhu's algorithm. The proposed attack indicates that the Arnold cat map applied directly in image encryptions is not suitable for cryptography. We also propose the corresponding improved scheme. The improved scheme preserves the merits of the original one.