A novel encryption method combining software algorithm and spatial light modulator

Images can convey information and needs to be protected, which is usually done by encryption. Traditional image encryption methods usually use software or hardware encryption, which has improvement approach in terms of better safety and robustness. And the study arouses sympathy to researchers based on both software and hardware encryption. This paper proposes an encryption method that combines software algorithm encryption and hardware encryption using a spatial light modulation (SLM) and 4f optical system. Firstly, the image is chaotically encrypted using the chaos encryption algorithm. Secondly, the discrete cosine transform (DCT) is adopted for further encryption based on chaos encryption picture. Thirdly, the cipher text image is transformed into the 4f system using SLM, which performs a random amplitude on the image to achieve hardware encryption. Finally, the simulation and experiment are performed to verify that the scheme, which shows that the method can realize the encryption and unencryption under the combination of software and hardware encryption. The proposed method has application value to guarantee the higher security of information.