明文图像；解密图像
例句：
1. A known plaintexts attack is proposed by exhaustive parameter search.For a M×N plain image,the computing complexity is O(M+N).
对于大小为M×N的明文图像,该攻击方法的计算复杂性为O(M+N).
2. For the encryption algorithm in frequency domain,the cipher-image can be lossy compressed,and low-distortion plain image can be obtained after decrypting the compressed cipher-image.
频率域加密密文图像能根据传输率要求随时进行相应压缩比的有损压缩,并能解密得到较低失真率的解密图像.