Fast color image encryption algorithm based on FCSM and pre-storage Arnold transform

Image encryption is an important multimedia security technology to protect the image content during network transmission. Chaotic systems are widely used in the field of image encryption due to their pseudo-randomness. To solve the problem of poor chaotic effect of traditional chaotic systems, this paper proposes a novel Fibonacci combined Cubic-Sine Map (FCSM) with large key space and chaotic characteristics, which passes each of NIST SP 800-22 tests. Besides, a fast color image encryption algorithm is designed using FCSM and pre-storage Arnold transform. Firstly, the SHA-256 is used to generate initial values; secondly, pseudo-random sequences are generated using FCSM, which scramble the image in combination with the row & column shift and circular rotation; finally, the pre-storage Arnold transform is designed to diffuse the pixel values. The experimental results and security analyses show that the proposed algorithm has ideal encryption effect with NPCR and UACI reaching to 99.6096% and 33.4657%, which are very close to the ideal values. The proposed algorithm is very efficient, which takes only about 0.6 second to encrypt a color image with the size of 512 × 512. Therefore, the proposed algorithm is secure and efficient, which can be a candidate for the real-time encryption system.