Thumbnail-preserving encryption based on improved logistic system

Abstract

Plaintext images and images encrypted using traditional encryption schemes in cloud storage represent the extremes of usability and privacy. Recently, thumbnail-preserving encryption (TPE) has been proposed to balance the usability and privacy of images in the cloud. An ideal TPE scheme should achieve lossless decryption, the same thumbnail, low time complexity, and resistance to certain attacks, which are missing in existing TPE schemes. Motivated by this idea, we propose a new TPE scheme based on an improved logistic chaotic system, which takes advantage of the good dynamics of the chaotic system and withstands the experimental evaluations in terms of privacy and usability. In the encryption mechanism, we design the TPE scheme from the binary and rank-then-encrypt perspectives by randomly selecting pixels. Compared with the existing schemes, the proposed scheme can reach the ideal state with only one round of encryption. Meanwhile, the experimental results such as time cost, image visual quality and security analysis also show that the scheme has strong competitiveness.

Keywords

• Balance privacy and usability
• Cloud storage
• Image encryption
• Chaotic system