说明：  基于DCT的jsteg图像隐写及分析算法，MATLAB实现。 JSteg的算法主要思想是将秘密消息嵌入在量化后的DCT系数的最低比特位上，但对原始值为O、1的DCT系数不进行嵌入。提取秘密消息时，只需将载密图像中不等于0、l的量化DcT系数的LSB取出即可。
(The main idea of the JSteg algorithm is to embed secret messages in the lowest bit of the quantized DCT coefficients, but the DCT coefficients of the original values are O and 1 are not embedded. When extracting secret messages, only the LSB of the quantized DCT coefficients not equal to 0 and l in the encrypted image can be taken out.)