A high payload steganography scheme for color images based on BTC and hybrid strategy

Block Truncation Coding (BTC) is one of the popular compression techniques in the image data hiding because its low computation cost and easy to implement. For a color image, there exist three pairs of high mean and low mean with three bitmaps. Common bitmap is a good way for saving the size of compression code. Chang et al. presented a data hiding method to conceal secret data into color BTC compression code by rearranging high mean and low mean encoding sequences. The proposed method is attempting to embed more secret data into the color BTC compression code. In this paper, a novel method is proposed to encrypt the amount of the element '1'. If the amount is even number, then the data is implied to a secret bit '0', otherwise, will be implied to a secret bit '1'. Furthermore, the Less Significant Bit (LSB) of all high mean and low mean pairs can also be used to embed the secret data. Actually, in the proposed method, each block conceals at least 10 secret bits.