证实了一种使用参考光波的光学联合相关变换加密系统对于选择明文攻击的脆弱性。在该加密系统中，通过选择一个透过率为零的特殊明文图像，记录其对应的联合功率谱，之后再通过遮挡输入面获取参考光波强度、遮挡参考光和明文获得加密密钥的傅里叶变换强度，根据获得的3幅图像，攻击者可以准确地获取加密所用的密钥,进而可以恢复出原始图像。理论分析和计算机模拟结果均证明所提攻击方法的有效性。

In this paper we demonstrate that the optical encryption scheme with a reference wave in joint transform correlator (JTC) is vulnerable to the chosen-plaintext attack (KPA) from the point of view of cryptanalysis. First of all, we selected a dark image as the plaintext and recorded its joint power spectrum, then we recorded the intensity of the reference wave by keeping the input plane out, thereafter we recorded the intensity of the Fourier transform of the encrypting key by sheltering the reference wave and the plaintext. With the obtained three images, the intruder could retrieve the encryption key with the help of several skillful steps. Consequently, the intruder could further access the plaintext with the retrieved key. The theoretical analysis and a set of numerical simulations were carried out to demonstrate how the secret key of the encryption system could be derived out with our proposed strategy.