A multi-image encryption-then-compression scheme based on parallel compressed sensing

Compressing encrypted images by using compressed sensing (CS) has become a hot topic in recent years. However, the traditional CS-based schemes can only process single image, which do not support batch process. To address this concern, a multi-image encryption-then-compression (ETC) scheme based on parallel CS (PCS) for secure cloud storage is proposed in this paper. In the proposed scheme, multiple images are assembled into a big combined image firstly and then the combined image is encrypted by using the scrambling encryption operation. Secondly, PCS is utilized to compress the encrypted combined image. Lastly, a dual prior reconstruction (DPR) algorithm is proposed for image recovery. Experimental results show that the proposed method has two advantages. First, it supports batch processing, which can process multiple images simultaneously. Second, it can get better security performance and compression performance than the previous ETC methods.