Research On Encryption And Decryption Technology Of Visual Images Based On Optical Transformation

Optical image encryption technology is an image encryption technology based on the optical principle.Optical image encryption technology has several advantages such as security,parallelism,and multiple degrees of freedom,and is widely used in many information security fields such as digital anti-counterfeiting,communication encryption,and security authentication.However,the current optical image encryption technology still has the defects of poor robustness and practical application,so this paper proposes the visual image encryption and decryption technology based on optical coherent logic operation and the image encryption technology based on multimode fiber chaotic transmission,and the main research work includes the following aspects.1.A visual image encryption and decryption technique based on optical coherent logic operations is proposed and designed.The visual cryptography algorithm is used to transform the plaintext image into two ciphertext images.In decryption,the two cryptographic carriers are placed in the decryption system,and the decryption result is based on the optical image coherent subtraction principle to achieve the optical "XOR" operation.Compared with the traditional visual cryptographic decryption method based on "OR" operation,which causes edge distortion and low signal-to-noise ratio,the optical decryption method based on "XOR" logic operation proposed in this paper can effectively improve the quality of decrypted images.2.In the encryption process,the key is generated according to the different states of the internal scrambling of the fiber scattering encryption system,and the original image and the transmission matrix data set are loaded and modulated by the SLM(spatial optical modulation demodulator)in the system to generate the corresponding scattering encrypted image and scattering matrix at the output of the multimode fiber.image and scatter matrix.When decrypting,the original image can be recovered in high resolution by simply correlating the scatter image with the scatter matrix of its corresponding key.