To realize optical image encryption for long-distance transmission while considering its security performance, an optical image encryption scheme is proposed in this paper. In the scheme, the pixel information of the plaintext image is first encoded by orbital angular momentum (OAM) holograms; then, the information-coded OAM beam is transmitted through a 1 km multimode fiber to generate speckles as ciphertexts for encryption; and finally, a pre-trained deep learning model capable of learning the relationship between the output speckles and the input information-coded OAM modes is used for decryption. The proposed scheme is not only able to achieve high fidelity recovered image but also a remarkable level of security. The high security stems from the combined use of three keys: the order key, the model key, and the coder key, during optical encryption. The image can therefore only be decrypted by authorized users who simultaneously know the three keys. We have experimentally demonstrated the high fidelity and high security encryption/decryption capabilities. Our work can provide a promising avenue for further research into long-distance optical image transmission and encryption with ultra-high security.

中文翻译：

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通过多模光纤使用斑点进行超安全光学图像加密


为了实现远距离传输的光学图像加密，同时考虑其安全性，该文提出一种光学图像加密方案。在该方案中，纯文本图像的像素信息首先由轨道角动量 （OAM） 全息图编码;然后，将信息编码的 OAM 波束通过 1 km 多模光纤传输，生成斑点作为密文进行加密;最后，使用能够学习输出斑点和输入信息编码的 OAM 模式之间关系的预训练深度学习模型进行解密。所提出的方案不仅能够实现高保真恢复图像，而且具有卓越的安全性。高安全性源于在光学加密期间组合使用三个密钥：订单密钥、模型密钥和编码器密钥。因此，映像只能由同时知道这三个密钥的授权用户解密。我们已经实验证明了高保真和高安全性的加密/解密功能。我们的工作可以为进一步研究具有超高安全性的长距离光图像传输和加密提供一条有前途的途径。