非线性光学图像加密

Nonlinear Optical Image Encryption

结合传统的双随机相位编码和非线性光学技术的优点,提出一种基于光折变晶体自相位调制原理的非线性光学图像加密技术,并分析了其稳健性和安全性。该技术通过两个统计独立的随机相位板和两次非线性传播把明文图像加密成平稳的复随机白噪声。解密是加密的逆过程,既可以用光学的方法实现,也可以用非线性数字全息的方法实现。数值模拟结果证明,该加密系统在受加性噪声和乘性噪声影响的情况下,具有良好的稳健性,与传统的线性加密技术相比,该技术可以有效抵御选择明文和已知明文攻击。

Taking the advantages of the traditional double random phase encoding and nonlinear optics techniques, a novel nonlinear optical image encryption technique based on self-phase modulation of photorefractive crystal is proposed, the robustness and security are analyzed. The plaintext image is encrypted into a stationary complex random white noise via two statistically independent random phase masks and two sequential nonlinear propagations. The decryption is the inverse process of the encryption, which can be implemented either optically or digitally using nonlinear digital holography. Numerical simulation results demonstrate that the proposed nonlinear optical image encryption technique is robust against additive and multiplicative noise, resists effectively against the chosen plaintext attack or known plaintext attack based on phase retrieval in comparison with the traditional linear encryption techniques.