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At present, some image compression and encryption algorithms have been presented to protect digital images by combining chaos and compressed sensing (CS). However, some of them still suffer from security and efficiency shortcomings. To solve these issues, a multi-image compression and encryption based on 3D fractal cube, CS and chaos is introduced in this paper. Firstly, the multiple plain images are sparsified by the Haar Wavelet Transform (HWT), and measured by CS to obtain the measurement value matrices. Herein, a four-wing hyperchaotic system is adopted to generate the measurement matrix for CS. Subsequently, a 3D fractal cube (3D-FC) is defined and generated iteratively by constructing the initial 3D-FC. Based on it, the obtained measurement value matrices are shuffled to reduce the high correlation between the adjacent pixels. Next, the cipher images are obtained after the cipher-associated adaptive diffusion based on GF (28) is performed on the confused image. Moreover, we have conducted extensive experiments to verify the encryption efficiency, compression performance, and security. Both simulation results and performance analysis confirm that the present algorithm has satisfactory performance in these aspects. [ABSTRACT FROM AUTHOR]

Compressed sensing (CS) has been applied for image compression and encryption, for it may compress and encrypt images simultaneously. However, some CS-based image encryption algorithms still suffer from low security and compression performance. To solve these problems, a content-adaptive compression-encryption based on CS and RiboNucleic Acid (RNA) is proposed in this paper. Firstly, the 4D laser chaos system was used to construct a measurement matrix for image compression. Secondly, an Improved Fractal Sorting Matrix (IFSM) and its iterative approach are introduced based on the Fractal Sorting Matrix (FSM) for permutation. It has the same characteristics as FSM, but with a greater permutation effect and a broader range of applications. Finally, an adaptive RNA diffusion is designed based on the unique codon of RNA, which includes codon substitution and calculation operations. This adaptive operations make the algorithm more difficult to crack. Additionally, chaotic sequences driven by the hash value of plain image are utilized in the whole encryption, which enhances the correlation between the algorithm and plain image and improves the ability to resist known-plaintext and chosen-plaintext attacks. Experimental results and performance analyses demonstrate that the proposed scheme has excellent security and compression property. [ABSTRACT FROM AUTHOR]