Secure Image Encryption Based on Compressed Sensing and Scrambling for Internet-of-Multimedia Things

In this paper, we propose a secure image encryption system based on compressed sensing (CS) with a scrambling mechanism. For efficient encryption, we use a sparse measurement matrix, where the nonzero elements are generated by a linear feedback shift register (LFSR) based keystream generator. Then, several pairs of data scramblers, also based on LFSR, are attached behind the CS-encryption for diffusion. While guaranteeing theoretically reliable CS-decryption, numerical results indicate that the proposed cryptosystem has more reliable CS-decryption performance than other CS-based cryptosystems. Examining the histogram, entropy and correlation of the ciphertexts, experimental results demonstrate that the proposed cryptosystem has strong statistical security. Moreover, it turns out that the proposed cryptosystem has higher plaintext sensitivity than other CS-based cryptosystems, thanks to the bit-level diffusion from the scramblers.