A Novel Multi-Chaos Based Compressive Sensing Encryption Technique

Compressive sensing is a compression technique that can be effectively utilised in multimedia encryption. This paper proposes a new compressive sensing image encryption scheme using the Secure Hash Algorithm (SHA-512), Discrete Cosine Transform (DCT), orthogonal matrix and discrete Chirikov map-based random permutation. DCT is applied on a plaintext image and a block of DCT coefficients is multiplied with an orthogonal matrix. Inverse DCT and scaling are performed to restrict the values between 0 and 255. Furthermore, values are shuffled using Chirikov-based pseudo-random permutation. A strong trade-off exists between DCT block size and computational efficiency. The quality and Signal to Noise Ratio (SNR) of the decrypted image decreases when the size of the DCT matrix is reduced, increasing the speed of the encryption algorithm. An extensive security analyses of the proposed scheme are performed, which establishes the robustness, computational efficiency and security of the technique against cryptographic attacks.