其使用dct的方法实现图像水印，经检测，其鲁棒性较好，原图像不可见性也较好。包含了加密解密算法，可以实现不需要原图的解密。(The use of dct method to achieve image watermarking, after testing, its robustness is better, the original image invisibility is better. Contains the encryption and decryption algorithms,