LSB steganography with improved embedding efficiency and undetectability

In this paper, we propose a new method of non-adaptive LSB steganography in still images toimprove the embedding efficiency from 2 to 8/3 random bits per one embedding change even forthe embedding rate of 1 bit per pixel. The method takes 2-bits of the secret message at a timeand compares them to the LSBs of the two chosen pixel values for embedding, it always assumesa single mismatch between the two and uses the second LSB of the first pixel value to hold theindex of the mismatch. It is shown that the proposed method outperforms the security of LSBreplacement, LSB matching, and LSB matching revisited by reducing the probability ofdetection with their current targeted steganalysis methods. Other advantages of the proposedmethod are reducing the overall bit-level changes to the cover image for the same amount ofembedded data and avoiding complex calculations. Finally, the new method results in littleadditional distortion in the stego image, which could be tolerated.