In this paper new method of asymmetric optical encryption is presented. It is based on the double encryption using spatially incoherent illumination: to obtain a ciphertext a plaintext is encoded twice, first time by sender, second time—by recipient. This way no exchange of encryption keys is required. Two variants of this method were analyzed: one in which both encryption procedures are implemented optically and another one in which the first operation is done optically and the second one—numerically. Both variants were numerically simulated and the latter one was implemented optically. Results of numerical and optical experiments demonstrate high quality of decrypted images (decoding error 0.19), thus confirming usability of proposed method.

中文翻译：

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空间非相干照明下的非对称图像光学加密

本文提出了一种新的非对称光加密方法。它基于使用空间不相干照明的双重加密：为了获得密文，将纯文本进行两次编码，第一次是由发送者，第二次是由接收者。这样，无需交换加密密钥。分析了此方法的两个变体：一个变体中的两个加密过程都以光学方式实施，另一个变体中的第一个操作以光学方式完成，第二个操作是数字方式。两种变体都经过了数值模拟，而后一种则以光学方式实现。数值和光学实验结果表明，解密后的图像质量很高（解码误差为0.19），从而证实了所提方法的可用性。