TPE-DF: Thumbnail Preserving Encryption via Dual-2DCS Fusion

Thumbnail preserving encryption (TPE) images protect privacy while still maintaining visual usability when stored in the cloud. However, existing thumbnail preserving encryption techniques are insufficient in defending against statistical attack. Drawing on the ideas of 2D compressed sensing (2DCS), this letter proposes thumbnail preserving encryption via dual-2DCS fusion, called TPE-DF, which can resist statistical attack. The original image is processed by 2DCS with deterministic binary block diagonal (DBBD) sampling matrix to generate the sampled image. Then, the residual matrix ($RM$) is then constructed by subtracting the predictive reconstructed values of the sampled image from the original image. The sampled image is processed by dual-2DCS fusion with arbitrary scaling sensing degradation (ASSD) matrix to obtain a carrier image. Then, the bitstream of $RM$ is embedded in the carrier image to finally generate the TPE image. Experimental results show that a reversible TPE scheme with resistance to statistical attack is achieved.

I. Introduction

With cloud services offering massive amounts of online storage space to anyone [1], [2], more and more people are storing all kinds of images that record a lot of personal privacy [3], [4], [5] in the cloud, such as iCloud, Google Drive, and Skydrive. Original images uploaded to the cloud face a variety of privacy issues [6], such as active leakage by insecure cloud operators and illegal third-party attacks succeed [7], [8]. Platforms are constantly improving their security measures, but the most cutting-edge platforms still face the challenge of data breaches [9], [10], [11].