关键词: LSB密写, 重加密, 检测方案

Abstract: An improved LSB image steganography scheme is analyzed，which can resist RS statistical method and Chi-square statistical method.The scheme has two critical defects：One is that each encryption reduces the mean of all pixels of the image with very great possibility，and other is，there is strong correlation between the times of encryption and the degree reduced of the mean.Taking advantage of these two points，several statistics vectors can be designed as statistics characteristic vectors.With those vectors，this paper trains the FLD classifier，detects images，and utilizes the FLD classifier trained，and can successfully classify between cover images and steganography images.Based on above，a detection algorithm，can attack the improved LSB image steganography scheme，is proposed successfully.

Key words: LSB steganography, re-encryption, detection scheme