The algorithm makes uses of the invariant before and after JPEG compression, which the watermark is semi-fragilely embedded in DCT domain and the key is steadily bided in the carrier simultaneously.

• 利用JPEG压缩前后的不变量，把水印信息半脆弱地嵌入到图像的DCT域中，同时密钥也被稳健地隐藏在载体信息中。